JP2019179820A - Multilayer ceramic capacitor - Google Patents

Abstract

To provide a multilayer ceramic capacitor with high moisture resistance reliability.SOLUTION: A multilayer ceramic capacitor 10 includes: a lamination body 12 containing a plurality of dielectric layers 14 laminated and a plurality of inner electrodes 16 laminated; and an outer electrode 24 connected to each inner electrode 16, and arranged on end surfaces 12e and 12f of the lamination body 12. The outer electrode 24 includes a thermosetting resin and a conductive resin layer 28 having a metal. A boundary surface between a side of both ends of a width direction y of each inner electrode 16 and each dielectric layer 14 has gap parts 22a and 22b having an opening part in the end surfaces 12e and 12f of the lamination body 12. In the gap parts 22a and 22b, there is a resin 23 in which the hardness of a type D durometer defined in ISO868 is 70 or less, and the hardness of a type A durometer defined in JIS K6253 is 65 or more.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a multilayer ceramic capacitor, and more particularly to, for example, a multilayer ceramic capacitor including a multilayer body in which dielectric layers and internal electrodes are alternately stacked.

In recent years, a ceramic electronic component represented by a multilayer ceramic capacitor has been used in a harsher environment than before.
For example, electronic components used in mobile devices such as mobile phones and portable music players are required to withstand impacts when dropped. Specifically, it is necessary to prevent the electronic component from falling off the mounting substrate or cracking the electronic component even when subjected to a drop impact.
In addition, electronic components used in in-vehicle devices such as ECUs are required to withstand thermal cycle impacts. Specifically, it is necessary to prevent the electronic component and the solder for mounting from cracking even if the mounting substrate receives a flexural stress generated by thermal expansion and contraction of the mounting substrate.

  In response, ceramic electronic components having external electrodes using thermosetting resins or the like as external electrodes have been proposed. For example, Patent Document 1 discloses a resin formed by using a thermosetting conductive paste on a chip-shaped element (laminated body) after forming an external electrode formed of a baked conductive paste as usual. A ceramic electronic component (multilayer ceramic capacitor) including an external electrode provided with an electrode layer and a plating film formed thereon is described. As described above, by disposing the resin electrode layer between the external electrode formed of the fired conductive paste and the plating film, the external stress can be absorbed by the resin electrode layer.

  Further, for example, in Patent Document 2, a ceramic body (laminated layer) is provided without providing an external electrode formed of a conventional fired conductive paste formed on a ceramic body (laminated body) as in Patent Document 1. A first conductive layer formed on the body using a thermosetting conductive paste containing metal powder and resin, and a second conductive layer made of a plating film formed on the first conductive layer. A ceramic electronic component (multilayer ceramic capacitor) having an external electrode is described.

JP-A-10-284343 International Publication No. 2004/053901

However, in general, the resin electrode layer has low denseness and cannot secure sealing performance, so that moisture resistance reliability is low. Therefore, in either of the structures of Patent Document 1 and Patent Document 2, moisture or the like enters the ceramic electronic component (multilayer ceramic capacitor), which causes a problem that the reliability of the ceramic electronic component (multilayer ceramic capacitor) is lowered. was there.
In particular, the structure of Patent Document 2 has a significant problem because the base electrode layer (sintered metal film formed of a baked conductive paste) is not formed. Even in the structure of Patent Document 1, since the height dimension of the product is limited, it is necessary to reduce the thickness of the external electrode, and it is necessary to reduce the thickness of the base electrode layer. Similarly, the moisture resistance is low.
Furthermore, the ceramic green sheet and the internal electrode differ in the amount of shrinkage during firing, and the internal electrode shrinks more greatly. Therefore, generally between the end face of the laminate and the end of the internal electrode, the dielectric layer May cause gaps. As a result, in the resin external electrode product that has a weak adhesion to the laminate, the gaps as described above are generated, which makes it easier for moisture to enter the ceramic electronic component (multilayer ceramic capacitor). The reliability of electronic components (multilayer ceramic capacitors) may be significantly reduced.

  Therefore, an object of the present invention is to provide a multilayer ceramic capacitor having high moisture resistance reliability.

  A first main surface and a second main surface that are opposite to each other in the stacking direction, and that are opposite to each other in the width direction perpendicular to the stacking direction, including a plurality of stacked dielectric layers and a plurality of stacked internal electrodes. And a second end surface, a first end surface and a second end surface opposite to each other in a length direction perpendicular to the stacking direction and the width direction, and a stack on at least the first end surface of the stack And a second external electrode disposed on at least a second end surface of the laminate, and the internal electrode is disposed on the dielectric layer and is disposed on the first end surface. A first internal electrode drawn out and a second internal electrode arranged on the dielectric layer and drawn out to the second end face, wherein the first external electrode is a conductive material including a thermosetting resin and a metal. The second external electrode includes a conductive resin layer including a thermosetting resin and a metal. The first inner electrode has a first gap portion having an opening at the first end face at the interface between the both sides in the width direction of the first inner electrode and the dielectric layer, and the width of the second inner electrode. There is a second gap portion having an opening on the second end face at the interface between the both ends in the direction and the dielectric layer, and the first and second gap portions are defined in ISO868. A multilayer ceramic capacitor in which a type D durometer has a hardness of 70 or less and a resin having a type A durometer specified in JIS K6253 has a hardness of 65 or more.

  According to the multilayer ceramic capacitor in accordance with the present invention, the first end face disposed at the first end face or the second end face at the interface between the both sides in the width direction of the internal electrode and the dielectric layer has the first opening. Resin having a specific hardness exists in the gap portion and the second gap portion. Therefore, since the gap can be sealed with resin, it is possible to suppress the intrusion of moisture into the multilayer ceramic capacitor.

  According to the present invention, a multilayer ceramic capacitor having high moisture resistance reliability can be provided.

  The above-described object, other objects, features, and advantages of the present invention will become more apparent from the following description of embodiments for carrying out the invention with reference to the drawings.

1 is an external perspective view showing an example of a multilayer ceramic capacitor according to the present invention. It is sectional drawing in the II-II line | wire of FIG. 1 which shows the multilayer ceramic capacitor concerning this invention. It is sectional drawing in the III-III line of FIG. 1 which shows the multilayer ceramic capacitor concerning this invention. FIG. 4A is a cross-sectional view taken along line IVA-IVA shown in FIG. 4B is a cross-sectional view taken along line IVB-IVB shown in FIG. 1 is a partial cross-sectional view of a multilayer ceramic capacitor according to the present invention. It is LT sectional drawing which concerns on another embodiment of the multilayer ceramic capacitor concerning this invention.

1. Multilayer Ceramic Capacitor The multilayer ceramic capacitor according to the present invention will be described. FIG. 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to the present invention. 2 is a cross-sectional view taken along the line II-II of FIG. 1 showing the multilayer ceramic capacitor according to the present invention. 3 is a cross-sectional view taken along the line III-III of FIG. 1 showing the multilayer ceramic capacitor according to the present invention. FIG. 4A is a cross-sectional view taken along line IVA-IVA shown in FIG. 4B is a cross-sectional view taken along line IVB-IVB shown in FIG.

  As shown in FIGS. 1 to 4, the multilayer ceramic capacitor 10 includes a multilayer body 12 having a substantially rectangular parallelepiped shape.

(Laminated body 12)
The stacked body 12 includes a plurality of stacked dielectric layers 14 and a plurality of internal electrodes 16, and is orthogonal to the first and second main surfaces 12 a and 12 b facing the stacking direction x. A first side surface 12c and a second side surface 12d that are opposed to the width direction y, a first end surface 12e and a second end surface 12f that are opposed to the length direction z orthogonal to the stacking direction x and the width direction y, including. Moreover, it is preferable that the laminated body 12 is rounded in the corner | angular part or the ridgeline part. In addition, a corner | angular part is a part where 3 adjacent surfaces of the laminated body 12 cross, and a ridgeline part is a part where 2 adjacent surfaces of the laminated body 12 intersect. Further, unevenness or the like is formed on part or all of the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, and the first end surface 12e and the second end surface 12f. May be.

(Dielectric layer 14)
The dielectric layer 14 of the stacked body 12 includes an outer layer portion 14a and an inner layer portion 14b. The outer layer portion 14a is located on the first main surface 12a side and the second main surface 12b side of the laminate 12, and is between the first main surface 12a and the inner electrode 16 closest to the first main surface 12a. And a dielectric layer located between the second main surface 12b and the internal electrode 16 closest to the second main surface 12b. The region sandwiched between both outer layer portions 14a is the inner layer portion 14b.

As the ceramic material of the dielectric layer 14 of the multilayer body 12, for example, a dielectric ceramic made of a main component such as BaTiO ₃ , CaTiO ₃ , SrTiO ₃ , or CaZrO ₃ can be used. Moreover, you may use what added subcomponents with less content than main components, such as a Mn compound, Fe compound, Cr compound, Co compound, Ni compound, to these main components.

  The thickness of the dielectric layer 14 after firing is preferably 0.5 μm or more and 10 μm or less.

As shown in FIG. 4A, a first gap portion having an opening in the first end face 12e at the interface between the both ends in the width direction y of the first internal electrode 16a and the dielectric layer 14 22a.
As shown in FIG. 4B, a second gap portion having an opening in the second end face 12f is formed at the interface between the both ends in the width direction y of the second internal electrode 16b and the dielectric layer 14. 22b.

  Resin 23 is present in the first gap portion 22a and the second gap portion 22b of the laminate 12, and the hardness of the resin 23 is 70 or less in the hardness of the type D durometer defined in ISO868. And the hardness of the type A durometer prescribed in JIS K6253 is 65 or more. Thus, in the present invention, since the resin 23 having a specific hardness exists in the first gap portion 22a and the second gap portion 22b, the first gap portion 22a and the second gap portion 22b are replaced with each other. It can be sealed with the resin 23, and moisture can be prevented from entering the multilayer ceramic capacitor 10. Therefore, it is possible to provide the multilayer ceramic capacitor 10 having high moisture resistance reliability.

  As shown in FIGS. 3 and 4, a first gap 22a and a second gap 22b are formed between the dielectric layer 14 and the internal electrode 16, and the resin 23 is partially or continuously formed. Is filled.

  The resin 23 is preferably a compound composed of an organic substance and silicon. The compound is preferably a dehydration condensation type organopolysiloxane. By using the dehydration-condensation type organopolysiloxane, the laminate 12 is familiar and wets well. In addition, since the adhesiveness with the oxide is good, sealing can be performed without a gap.

(Internal electrode 16)
Inside the laminate 12, a first internal electrode 16a drawn to the first end face 12e and a second internal electrode 16b drawn to the second end face 12f are arranged. The plurality of first internal electrodes 16 a and second internal electrodes 16 b are stacked so as to be alternately arranged at equal intervals along the stacking direction x of the stacked body 12 with the dielectric layer 14 interposed therebetween.

The first internal electrode 16a includes a first counter electrode portion 18a facing each other, and a first extraction electrode portion 20a extending from the first counter electrode portion 18a to the first end face 12e of the multilayer body 12. Yes.
The second internal electrode 16b includes a second counter electrode portion 18b facing each other, and a second extraction electrode portion 20b extending from the second counter electrode portion 18b to the second end face 12f of the multilayer body 12. Yes.

  The first internal electrode 16a and the second internal electrode 16b are appropriately made of, for example, a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy containing at least one of these metals such as an Ag—Pd alloy. The conductive material can be used.

  In the present embodiment, the counter electrodes 18a and 18b of the internal electrode 16 are opposed to each other with the dielectric layer 14 therebetween, whereby a capacitance is formed and the characteristics of the capacitor are expressed.

  The thickness of each of the first internal electrode 16a and the second internal electrode 16b is preferably 0.2 μm or more and 2.0 μm or less, for example.

(External electrode 24)
On at least the first end surface 12e of the laminate 12, a first external electrode 24a including a conductive resin layer 28 including a resin and a metal, and a second external including a conductive resin layer 28 including a resin and a metal. And electrode 24b.

  The first external electrode 24 a and the second external electrode 24 b in this embodiment are disposed on the base electrode layer 26, the conductive resin layer 28 disposed on the base electrode layer 26, and the conductive resin layer 28. The plating layer 30 is preferably provided.

  In the present embodiment, the first external electrode 24 a and the second external electrode 24 b are provided on the base electrode layer 26, the conductive resin layer 28 disposed on the base electrode layer 26, and the conductive resin layer 28. However, as shown in FIG. 6, the base electrode layer 26 may not be formed and only the conductive resin layer 28 and the plating layer 30 may be formed. . Specifically, a structure in which the conductive resin layer 28 is disposed directly on the surface of the laminate 12 and the plating layer 30 is disposed on the conductive resin layer 28 may be employed. When the base electrode layer 26 is not formed in the first external electrode 24a and the second external electrode 24b, the problem of the present application appears more remarkably. Therefore, the problem can be effectively prevented by applying the feature of the present application.

(Base electrode layer 26)
The base electrode layer 26 includes a first base electrode layer 26a and a second base electrode layer 26b.

The first base electrode layer 26a covers the first end surface 12e of the multilayer body 12, and reaches the first main surface 12a and the second main surface 12b, and the first side surface 12c and the second side surface 12d. Is provided. However, the first base electrode layer 26a may be disposed only on the first end face 12e.
The second base electrode layer 26b covers the second end surface 12f of the multilayer body 12 and reaches the first main surface 12a and the second main surface 12b, and the first side surface 12c and the second side surface 12d. Is provided. However, the second base electrode layer 26b may be disposed only on the second end face 12f.

  The first base electrode layer 26a and the second base electrode layer 26b are formed, for example, by applying and baking a conductive paste containing a conductive metal and glass.

  For example, Cu, Ni, Ag, Pd, an Ag—Pd alloy, Au, or the like can be used as the conductive metal of the first base electrode layer 26a and the second base electrode layer 26b.

  As the glass of the first base electrode layer 26a and the second base electrode layer 26b, for example, glass containing B, Si, Ba, Mg, Al, Li, or the like can be used. Moreover, you may use the same kind of ceramic material as the dielectric material layer 14 instead of glass.

  The first base electrode layer 26a and the second base electrode layer 26b may be fired simultaneously with the internal electrode 16, or may be fired by applying a conductive paste. In the case of simultaneous firing with the internal electrode 16, it is preferable to use a ceramic material of the same type as the dielectric layer 14 instead of glass.

  The thickness (thickest portion) of the first base electrode layer 26a and the second base electrode layer 26b is preferably 10 μm or more and 50 μm or less.

(Conductive resin layer 28)
The conductive resin layer 28 includes a first conductive resin layer 28a and a second conductive resin layer 28b.

  The first conductive resin layer 28a is disposed so as to cover the first base electrode layer 26a. Specifically, the first conductive resin layer 28a is disposed on the first end surface 12e on the first base electrode layer 26a, and the first main surface 12a and the first main surface 12a on the first base electrode layer 26a. The second main surface 12b is preferably provided so as to reach the first side surface 12c and the second side surface 12d. But the 1st conductive resin layer 28a may be distribute | arranged only on the 1st end surface 12e on the 1st base electrode layer 26a. Further, the first conductive resin layer 28a may not be provided so as to completely cover the first base electrode layer 26a. In other words, the first conductive resin layer 28a may be provided with a shorter length than the first base electrode layer 26a.

  The second conductive resin layer 28b is disposed so as to cover the second base electrode layer 26b. Specifically, the second conductive resin layer 28b is disposed on the second end surface 12f on the second base electrode layer 26b, and the first main surface 12a and the second main surface 12a on the second base electrode layer 26b. The second main surface 12b is preferably provided so as to reach the first side surface 12c and the second side surface 12d. However, the second conductive resin layer 28b may be disposed only on the second end face 12f on the second base electrode layer 26b. Further, the second conductive resin layer 28b may not be provided so as to completely cover the second base electrode layer 26b. In other words, the second conductive resin layer 28b may be provided with a shorter length than the second base electrode layer 26b.

  The thickness of the first conductive resin layer 28a and the second conductive resin layer 28b is preferably 10 μm or more and 150 μm or less, for example.

  The first conductive resin layer 28a and the second conductive resin layer 28b include a thermosetting resin and a metal component.

  As specific examples of the thermosetting resin, various known thermosetting resins such as an epoxy resin, a phenol resin, a urethane resin, a silicone resin, and a polyimide resin can be used. Among them, an epoxy resin excellent in heat resistance, moisture resistance, adhesion and the like is one of the most appropriate resins.

  Since the first conductive resin layer 28a and the second conductive resin layer 28b include a thermosetting resin, for example, the first conductive resin layer 28a and the second conductive resin layer 28b are more flexible than the base electrode layer 26 made of a fired product of a plating film or a conductive paste. It is out. For this reason, even when a physical impact or an impact due to a thermal cycle is applied to the multilayer ceramic capacitor 10, the conductive resin layer 28 functions as a buffer layer and prevents cracks in the multilayer ceramic capacitor 10. be able to.

  The first external electrode layer 24a and the second external electrode layer 24b preferably contain a curing agent together with the thermosetting resin. As the curing agent, when an epoxy resin is used as the base resin, various known compounds such as phenol, amine, acid anhydride, and imidazole can be used as the curing agent for the epoxy resin.

  As the metal component, one type of metal powder may be used, or a plurality of types, for example, a metal powder consisting of a first metal component and a second metal component may be used. In particular, when the base electrode layer 26 is provided and the conductive resin layer 28 is formed, it is preferable to use one type of metal powder, and the conductive resin layer 28 is formed without providing the base electrode layer 26. In this case, it is preferable to use metal powder composed of the first metal component and the second metal component. When the base electrode layer 26 is provided and the conductive resin layer 28 is formed, by using a first metal component described later, the metal of the internal electrode 16 and the first metal component in the conductive resin layer 28 However, it becomes possible to alloy and increase the bonding strength.

  The shape of the metal component is not particularly limited. The conductive filler may be spherical, flat or the like. Moreover, the average particle diameter of a metal component is not specifically limited. The average particle diameter of the first and second metal components may be, for example, 0.3 μm or more and 10 μm or less.

  In the case where the metal component in the conductive resin layer 28 is composed of one type of metal component, Ag or metal powder coated with Ag on the surface of the base metal powder can be used as the metal component. Among these, it is preferable to use Ag. The reason why Ag is used for the conductive metal powder is that Ag is suitable for an electrode material because it has the lowest specific resistance among metals, and Ag is a noble metal, so it is not oxidized and has high weather resistance. The reason why the metal coated with Ag is used is that the metal of the base material can be made inexpensive while maintaining the above Ag characteristics.

  When the metal component in the conductive resin layer 28 is composed of the first metal component and the second metal component, the first metal component and the second metal component have a melting point of the first metal component. It is relatively low and the melting point of the second metal component is relatively high. The melting point of the first metal component is preferably, for example, 550 ° C. or lower, and more preferably 180 ° C. or higher and 340 ° C. or lower. The melting point of the second metal component is preferably 850 ° C. or higher and 1050 ° C. or lower, for example.

  The first metal component is preferably made of, for example, Sn, In, Bi, or an alloy containing at least one of these metals. Among these, the first metal component is more preferably made of Sn or an alloy containing Sn. Specific examples of the alloy containing Sn include, for example, Sn—Ag, Sn—Bi, Sn—Ag—Cu, and the like.

  During the heat treatment, the first metal component softens and flows at a relatively low temperature, and forms a compound with the metal constituting the internal electrode 16.

  The content of the first metal component with respect to the total weight of the first metal component, the second metal component, and the thermosetting resin in the first external electrode 24a and the second external electrode 24b after curing is 20% by weight. It is preferably 40% by weight or less and more preferably 22.0% by weight or more and 37.2% by weight or less. If the content of the first metal component is too small, the bonding strength between the laminate 12 and the conductive resin layer 28 may not be sufficiently ensured. Moreover, when there is too much content of a 1st metal component, the 2nd metal component and unreacted 1st metal component which remain | survive in the conductive resin layer 28 will increase, for example by the heat | fever etc. which are added at the time of reflow The conductive resin layer 28 may be deformed.

  The second metal component is preferably made of a metal such as Cu, Ag, Pd, Pt, Au, or an alloy containing at least one of these metals. Among these, the second metal component is preferably Cu or Ag.

  The content of the second metal component with respect to the total weight of the first metal component, the second metal component, and the thermosetting resin in the first external electrode 24a and the second external electrode 24b after curing is 30% by weight. It is preferably 70% by weight or less and more preferably 41.2% by weight or more and 64.0% by weight or less. If the content of the second metal component is too small, the conductivity of the first external electrode 24a and the second external electrode 24b may decrease, and the equivalent series resistance (ESR) of the multilayer ceramic capacitor may increase. Further, if the content of the second metal component is too large, the content of the thermosetting resin in the first external electrode 24a and the second external electrode 24b becomes too small, and the first external electrode 24a and the second external electrode 24b The stress relaxation effect of the external electrode 24b may become too low.

  The second metal component is mainly responsible for the conductivity of the first conductive resin layer 28a and the second conductive resin layer 28b. Specifically, when the second metal components are in contact with each other, or the first metal component and the second metal component are in contact with each other, the first external electrode 24a and the second external electrode 24b are placed inside. An energization path is formed.

  The content of the conductive resin with respect to the total weight of the first metal component, the second metal component, and the thermosetting resin in the first external electrode 24a and the second external electrode 24b after curing is 5% by weight or more and 40%. It is preferably no greater than wt%, more preferably no less than 9.8 wt% and no greater than 31.5 wt%. If the resin content is too small, the stress relaxation effect of the first external electrode 24a and the second external electrode 24b becomes too low, and the first external electrode 24a and the second external electrode 24 when stress is applied from the outside. In some cases, the impact is not sufficiently absorbed by the electrode 24b. In addition, if the content of the thermosetting resin is too large, the conductivity of the first external electrode 24a and the second external electrode 24b may be reduced, and the equivalent series resistance (ESR) of the multilayer ceramic capacitor may be increased. .

(Plating layer 30)
The plating layer 30 includes a first plating layer 30a and a second plating layer 30b.

  A first plating layer 30a is formed on the first conductive resin layer 28a. Specifically, the first plating layer 30a is disposed on the first end surface 12e on the first conductive resin layer 28a, and the first main surface 12a and the first main surface 12a on the first conductive resin layer 28a. The second main surface 12b is preferably provided so as to reach the first side surface 12c and the second side surface 12d. However, the first plating layer 30a may be disposed only on the first end face 12e on the first conductive resin layer 28a.

  A second plating layer 30b is formed on the second conductive resin layer 28b. Specifically, the second plating layer 30b is disposed on the second end surface 12f on the second conductive resin layer 28b, and the first main surface 12a and the second main surface 12a on the second conductive resin layer 28b. The second main surface 12b is preferably provided so as to reach the first side surface 12c and the second side surface 12f. However, the second plating layer 30b may be disposed only on the second end face 12f on the second conductive resin layer 28b.

  Furthermore, a first upper plating layer may be provided on the first plating layer 30a. The first upper plating layer is formed so as to cover the first plating layer 30a.

  Furthermore, a second upper plating layer may be provided on the second plating layer 30b. The second upper plating layer is formed so as to cover the second plating layer 30b.

  The first plating layer 30a and the second plating layer 30b are, for example, plated with one metal selected from the group consisting of Cu, Ni, Ag, Pd, Ag-Pd alloy, Au, or an alloy containing the metal. Preferably it consists of.

  It is preferable that the thickness of the 1st plating layer 30a and the 2nd plating layer 30b is 1 micrometer or more and 10 micrometers or less.

  The first upper plating layer and the second upper plating layer are, for example, one kind of metal selected from the group consisting of Cu, Ni, Sn, Pb, Au, Ag, Pd, Bi, and Zn, or an alloy containing the metal It is preferable to consist of plating.

  The thicknesses of the first upper plating layer and the second upper plating layer are preferably 1 μm or more and 10 μm or less.

  In the present embodiment, the first plating layer 30a and the second plating layer 30b are formed by Ni plating. By providing the Ni plating layer, it has solder barrier performance. In addition, the first upper plating layer and the second upper plating layer are formed by Sn plating. By providing the Sn plating layer, the solder wettability can be improved and the mounting can be facilitated.

2. Next, a method for manufacturing the multilayer ceramic capacitor 10 according to the present invention will be described.

(1) First, the laminate 12 having the first internal electrode 16a and the second internal electrode 16b is prepared. Specifically, first, a ceramic paste containing a ceramic powder is applied in a sheet form by, for example, a screen printing method and dried to produce a ceramic green sheet.

(2) Next, on the ceramic green sheet, a conductive paste for forming an internal electrode is applied in a predetermined pattern by, for example, a screen printing method, and the ceramic green sheet on which the conductive pattern for forming an internal electrode is formed; A ceramic green sheet on which no internal electrode forming conductive pattern is formed is prepared. The ceramic paste and the conductive paste for forming the internal electrode may contain, for example, a known binder or solvent.

(3) Next, a predetermined number of ceramic green sheets on which the internal electrode forming conductive pattern is not formed are stacked, and a ceramic green sheet on which the internal electrode forming conductive pattern is formed is sequentially stacked, A mother laminate is produced by laminating a predetermined number of ceramic green sheets on which no internal electrode forming conductive pattern is formed.

(4) If necessary, the mother laminate may be pressed in the stacking direction by means such as isostatic pressing.

(5) The mother laminate is cut into a predetermined shape and a plurality of raw laminates are produced. At this time, the raw laminated body may be subjected to barrel polishing or the like to round the ridge line portion or the corner portion.

(6) By firing the raw laminate, the first internal electrode 16a and the second internal electrode 16b are arranged inside, and the end portions of the first internal electrode 16a and the second internal electrode 16b However, the laminated body 12 drawn out to the first end face 12e or the second end face 12f is completed. Note that the firing temperature of the raw laminate can be appropriately set according to the ceramic material or conductive material used. The firing temperature of the raw laminate can be, for example, 900 ° C. or higher and 1300 ° C. or lower.

(7) The impregnation method of the resin 23 into the first gap portion 22a and the second gap portion 22b is performed by vacuum impregnation. After the laminate 12 is immersed in the precursor solution of the resin 23, vacuuming is performed to impregnate the first gap portion 22a and the second gap portion 22b with the precursor solution. Thereafter, the resin 23 is taken out from the precursor solution and cured by heating to fix the resin 23 to the first gap portion 22a and the second gap portion 22b. The impregnation method of the resin 23 is not limited to the above method, and any of an immersion method and a spray method can be used, and any of atmospheric pressure impregnation, vacuum impregnation, and vacuum pressure impregnation can be used. Moreover, in the impregnation method of the resin 23 of this invention, the removal process of the resin 23 of the excess part may be included. For the removal step, wiping, washing, cutting, or the like can be used. In the present invention, after immersion in the precursor solution, washing with an organic solvent is performed before heat curing.
The hardness of the resin 23 used in the present invention can be controlled by the crosslink density and the functional group introduced into the side chain. In the present invention, the hardness is controlled by adjusting the crosslinking density (R / Si ratio).

(8) A conductive paste is applied and baked on both end faces 12e and 12f of the fired laminate 12 to form a base electrode layer 26 of the external electrode 24. The baking temperature is preferably 700 ° C. or higher and 900 ° C. or lower.

(9) A conductive resin paste containing a conductive filler and a resin is applied so as to cover the base electrode layer 26, and heat treatment is performed at a temperature of 250 ° C. or higher and 550 ° C. or lower to thermally cure the resin.
The atmosphere during the heat treatment is preferably an N ₂ atmosphere. Further, in order to prevent the resin from scattering and to prevent oxidation of various metal components, the oxygen concentration is preferably suppressed to 100 ppm or less. Thereby, a conductive resin layer 28 is formed so as to cover the base electrode layer 26, and an intermediate metal layer is formed between the base electrode layer 26 and the conductive resin layer 28. The thickness of the intermediate metal layer can be controlled by the heat treatment temperature.

(10) A Ni plating layer is formed on the conductive resin layer 28. Electroplating is used as a method for forming the Ni plating layer.

(11) If necessary, an Sn plating layer is formed on the Ni plating layer.

  As described above, the multilayer ceramic capacitor 10 according to the present embodiment is manufactured.

  The filling rate viewed from the WT surface is evaluated using the following method.

The filling rate as viewed from the WT surface is observed using the FE-SEM at 10 locations for each of the first gap 22a and the second gap 22b. When there is even one in which the filling rate between the resin 23 and the first gap portion 22a and the second gap portion 22b is less than the following criteria, it is determined as x. In addition, when there is no resin 23 in an observation location, it will be observed additionally.
(A) The end face of the multilayer ceramic capacitor is polished along the width direction y, the external electrode 24 is removed, and the extraction electrode portions 20a and 20b of the internal electrode 16 are exposed. Next, the first gap portion 22a and the second gap portion 22b are enlarged and observed 30000 times with an FE-SEM to observe the sealed portion.
(A) The area ratio of the resin 23 at the observation location is measured, and the case of less than 90% is determined as x.

  The resin hardness is evaluated using the following method.

The evaluation method of resin hardness is hardness measurement according to JIS K6253. Use them as follows.
When the hardness is less than 20 with a type D durometer, a type A durometer is used.
If the type A durometer shows a hardness exceeding 90, use a type D durometer.
In addition, this standard is a measurement method for rubber-shaped resins, but the hardness that cannot be measured by rubber hardness (for example, what is generally called an elastomer or resin) is specified as a hardness of 70 or more with a type D durometer. To do.

  The reliability test is evaluated using the following method.

  In the reliability test, a rated voltage of 6.3 V was applied to each condition (n = 72 pcs), the temperature was 40 ° C., the relative humidity was 95%, and the deterioration rate of the insulation resistance value after 1000 hours (IR deterioration rate). evaluate. An insulation resistance value that is 30% lower than the initial value is determined as NG.

3. Experimental Example Next, a multilayer ceramic capacitor was manufactured by the method described above, and a reliability test was performed. Examples 1 to 4 were prepared by changing the hardness of the resin. The hardness of the resin was controlled by adjusting the crosslink density (R / Si ratio).
As Comparative Example 1, a multilayer ceramic capacitor prepared without providing resin in the first gap portion 22a and the second gap portion 22b was prepared. The structure was the same as in the example except that no resin was provided. Furthermore, as Comparative Example 2 and Comparative Example 3, those whose resin hardness deviated from the scope of the present invention were prepared.

(1) Chip Specifications of Examples The following chips were used for the multilayer ceramic capacitor 10 of the present invention.
(A) Chip size (target value): L × W × T = 1.0 mm × 0.5 mm × 0.5 mm
(B) Ceramic material: BaTiO ₃
(C) Internal electrode: Ni
(D) Capacity: 10 μF
(E) Rated voltage: 6.3V
(F) Structure of external electrode (i) Material of base electrode layer: Cu
(Ii) Conductive resin layer: metal component Ag (only one type of metal component)
Resin Component Epoxy Resin (iii) Plating Layer: Ni Plating Layer + Sn Plating Layer Two-Layer Structure (g) Type of Resin Intervened in Gap: Organopolysiloxane (h) Hardness of Resin Intervened in Gap: Listed in Table 1

  About these obtained samples, the filling rate was evaluated and a reliability test was performed.

(2) Evaluation method of filling rate seen from WT surface The filling rate seen from the WT surface is obtained by observing the first gap portion 22a and the second gap portion 22b using FE-SEM at 10 locations in each condition. It was. When the filling rate of the resin 23 and the first gap portion 22a and the second gap portion 22b was less than the following criteria, it was determined as x. In addition, when there was no resin 23 in an observation location, it added and observed.
(A) The end face of the multilayer ceramic capacitor 10 is polished along the width direction y, the external electrode 24 is removed, and the extraction electrode portions 20a and 20b of the internal electrode 16 are exposed. Next, the void part in the internal electrode 16 was enlarged and observed 30000 times by FE-SEM, and the sealing part was observed.
(A) The area ratio of the resin 23 with respect to the first gap portion 22a and the second gap portion 22b at the observation location was measured, and the case of less than 90% was determined as x.

(3) Evaluation method of resin hardness The evaluation method of resin hardness measured hardness according to JISK6253. We used properly as follows.
When the hardness was less than 20 with a type D durometer, a type A durometer was used.
When the type A durometer showed a hardness exceeding 90, a type D durometer was used.
This standard is a measurement method for rubber-shaped resins, but hardness (for example, what is generally called an elastomer or resin) that cannot be measured with a rubber hardness meter is 70 or more with a type D durometer. did.

(4) About reliability test In the reliability test, a rated voltage of 6.3 V was applied to each condition (n = 72 pcs), the temperature was 40 ° C., the relative humidity was 95%, and the insulation resistance value deteriorated after 1000 hours. The rate (IR deterioration rate) was evaluated. The insulation resistance value that was 30% lower than the initial value was judged as NG.

  The values in Table 1 show the results of reliability tests when the hardness of the resin in the first gap portion 22a and the second gap portion 22b is changed.

  From the above results, in the multilayer ceramic capacitor according to the present invention, the resin 23 having a specific hardness is interposed in the gaps 22a and 22b between the end of the internal electrode 16 and the end surfaces 12e and 12f of the multilayer body 12. Thus, the gaps 22a and 22b can be sealed with the resin 23, so that moisture can be prevented from entering the multilayer ceramic capacitor 10. Therefore, it is possible to provide the multilayer ceramic capacitor 10 having high moisture resistance reliability.

  In addition, this invention is not limited to the said embodiment, In the range of the summary, it changes variously.

DESCRIPTION OF SYMBOLS 10 Multilayer ceramic capacitor 12 Laminated body 12a 1st main surface 12b 2nd main surface 12c 1st side surface 12d 2nd side surface 12e 1st end surface 12f 2nd end surface 14 Dielectric layer 14a Outer layer part 14b Inner layer part 16 Internal electrode 16a First internal electrode 16b Second internal electrode 18a First counter electrode part 18b Second counter electrode part 20a First extraction electrode part 20b Second extraction electrode part 22a First gap part 22b First 2 gap 23 resin 24 external electrode 24a first external electrode 24b second external electrode 26 base electrode layer 26a first base electrode layer 26b second base electrode layer 28 conductive resin layer 28a first conductive Resin layer 28b Second conductive resin layer 30 Plating layer 30a First plating layer 30b Second plating layer x Stacking direction y Width direction z Length direction L Length direction Length T length in the stacking direction W length in the width direction

Claims (3)

A first main surface and a second main surface that are opposite to each other in the stacking direction, and that are opposite to each other in the width direction perpendicular to the stacking direction. A laminate including the side surface and the second side surface, and a first end surface and a second end surface facing the length direction perpendicular to the stacking direction and the width direction;
A first external electrode disposed on at least the first end face of the laminate;
A second external electrode disposed on at least the second end face of the laminate;
Have
The internal electrode includes a first internal electrode disposed on the dielectric layer and drawn out to the first end surface, and a second internal electrode disposed on the dielectric layer and drawn out to the second end surface. Have
The first external electrode includes a conductive resin layer containing a thermosetting resin and a metal,
The second external electrode includes a conductive resin layer including a thermosetting resin and a metal,
The interface between the both sides in the width direction of the first internal electrode and the dielectric layer has a first gap portion having an opening at the first end surface;
The second inner electrode has a second gap portion having an opening in the second end face at the interface between the both sides in the width direction of the second internal electrode and the dielectric layer;
In the first and second gap portions, a resin having a type D durometer specified in ISO868 of 70 or less and a type A durometer specified in JIS K6253 having a hardness of 65 or more is used. An existing multilayer ceramic capacitor.   The multilayer ceramic capacitor according to claim 1, wherein the resin is a compound composed of an organic substance and silicon.   The multilayer ceramic capacitor according to claim 2, wherein the compound is a dehydration condensation type organopolysiloxane.

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