Method of manufacturing multilayer ceramic capacitor

A method of manufacturing a multilayer ceramic capacitor includes alternately laminating dielectric layers and internal electrode layers to manufacture a multilayer body, forming an external electrode connected with the internal electrode layers on each of two end surfaces of the multilayer body to manufacture a capacitor main body, connecting two interposers via an insulator, holding the two interposers connected via the insulator on a holding portion, placing the capacitor main body on the two interposers on the holding portion such that the external electrode is connected to each of the two interposers, and removing the holding portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2020-169697, filed on Oct. 7, 2020, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing a multilayer ceramic capacitor.

2. Description of the Related Art

Recently, a large capacitance, small multilayer ceramic capacitor has been demanded. Such a multilayer ceramic capacitor has an inner layer portion in which the dielectric layers including a ferroelectric material of relatively high dielectric constant, and the inner electrodes are alternately laminated.

Furthermore, dielectric layers serving as outer layer portions are formed on the upper and lower portions of the inner layer portion, thereby providing a rectangular parallelepiped multilayer body, and external electrodes are provided on both end surfaces in the length direction of the multilayer body, thereby forming a capacitor main body.

Furthermore, in order to suppress or prevent the generation of “acoustic noise”, a multilayer ceramic capacitor has been known which includes an interposer provided on the side of the capacitor main body mounted on a board (refer to PCT International Publication No. WO2015/098990).

However, it is difficult to position an interposer relative to a capacitor main body with good precision when mounting the interposer to a portion of an external electrode of the capacitor main body.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide methods of manufacturing multilayer ceramic capacitors that are each able to facilitate positioning of an interposer relative to a capacitor main body.

A preferred embodiment of the present invention provides a method of manufacturing a multilayer ceramic capacitor that includes alternately laminating dielectric layers and internal electrode layers to manufacture a multilayer body, forming an external electrode connected with the internal electrode layers on each of two end surfaces of the multilayer body to manufacture a capacitor main body, connecting two interposers via an insulator, holding the two interposers connected via the insulator on a holding portion, placing the capacitor main body on the two interposers on the holding portion such that the external electrode is connected to each of the two interposers, and removing the holding portion.

According to preferred embodiments of the present invention, it is possible to provide methods of manufacturing multilayer ceramic capacitors that are each able to facilitate positioning of an interposer relative to a capacitor main body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described below with reference to the drawings.FIG.1is a schematic perspective view of a multilayer ceramic capacitor1according to a preferred embodiment of the present invention.FIG.2is a partial cross-sectional view taken along the line II-II inFIG.1of the multilayer ceramic capacitor1.FIG.3is a cross-sectional view taken along the line III-III inFIG.1of the multilayer ceramic capacitor1. The line II-II passes through the middle in the width direction W described later of the multilayer ceramic capacitor1, and the line III-III passes through the middle in the length direction L described later.

The multilayer ceramic capacitor1has a rectangular or substantially rectangular parallelepiped shape, and includes a capacitor main body1A including a multilayer body2and a pair of external electrodes3provided at both ends of the multilayer body2, and an interposer4attached to the capacitor main body1A. Furthermore, the multilayer body2includes an inner layer portion including a plurality of sets of dielectric layers14and internal electrode layers15.

In the following description, as terms representing the orientation of the multilayer ceramic capacitor1, the direction in which the pair of external electrodes3are provided is referred to as a length direction L. The direction in which the dielectric layers14and the internal electrode layers15are laminated (stacked) is referred to as a lamination direction T. The direction intersecting both the length direction L and the lamination direction T is referred to as a width direction W. In the present preferred embodiment, the width direction W is perpendicular or substantially perpendicular to both the length direction L and the lamination direction T.

Outer Surface of Multilayer Body2

Among the six outer surfaces of the multilayer body2, a pair of outer surfaces opposing each other in the lamination direction T are referred to as a multilayer body first main surface AS1and a multilayer body second main surface AS2, respectively, a pair of outer surfaces opposing each other in the width direction W are referred to as a multilayer body first side surface BS1and a multilayer body second side surface BS2, respectively, and a pair of outer surfaces opposing each other in the length direction L are referred to as a multilayer body first end surface CS1and a multilayer body second end surface CS2.

When it is not necessary to particularly distinguish between the multilayer body first main surface AS1and the multilayer body second main surface AS2, they are collectively referred to as a multilayer body main surface AS, when it is not necessary to particularly distinguish between the multilayer body first side surface BS1and the multilayer body second side surface BS2, they are collectively referred to as a multilayer body main surface BS, and when it is not necessary to particularly distinguish between the multilayer body first end surface CS1and the multilayer body second end surface CS2, they are collectively referred to as a multilayer body end surface CS.

Outer Surface of Capacitor Main Body1A

Among the six outer surfaces of the capacitor main body1A, a pair of outer surfaces opposing each other in the lamination direction T is referred to as a capacitor first main surface AC1and a capacitor second main surface AC2, respectively, a pair of outer surfaces opposing each other in the width direction W is referred to as a capacitor first side surface BC1and a capacitor second side surface BC2, respectively, and a pair of outer surfaces opposing each other in the length direction L is referred to as a capacitor first end surface CC1and a capacitor second end surface CC2, respectively.

When it is not necessary to particularly distinguish between the capacitor first main surface AC1and the capacitor second main surface AC2, they are collectively referred to as a capacitor main surface AC, when it is not necessary to particularly distinguish between the capacitor first side surface BC1and the capacitor second side surface BC2, they are collectively referred to as a capacitor main surface BC, and when it is not necessary to particularly distinguish between the capacitor first end surface CC1and the capacitor second end surface CC2, they are collectively referred to as a capacitor end surface CC.

Outer Surface of Interposer4

Furthermore, the interposer4includes a first interposer4A and a second interposer4B. Among the six outer surfaces of the first interposer4A and the second interposer4B, an outer surface close to the capacitor main body1A of a pair of outer surfaces opposed to each other in the lamination direction T are referred to as an interposer first main surface AI1, and an outer surface opposed thereto is referred to as an interposer second main surface AI2.

Of pairs of outer surfaces of the respective interposers4opposing each other in the length direction L, outer surfaces facing each other of the interposers4are referred to as interposer first end surfaces CI1, and outer surfaces opposed thereto are referred to as interposer second end surfaces CI2.

Of pairs of outer surfaces opposing each other in the width direction W in the respective interposers4, as shown inFIG.5described later, when viewed from the interposer first end surface CI1with the interposer second main surface AI2above, the surface on the right side is referred to as an interposer first side surface BI1, and the surface on the left side is referred to as an interposer second side surface BI2.

The interposer first main surfaces AI1are close to the capacitor second main surface AC2, and the interposer first end surfaces CI1of the first interposer4A and the second interposer4B are opposed to each other.

When it is not necessary to particularly distinguish the interposer first main surface AI1and the interposer second main surface AI2from each other, they are collectively referred to as an interposer main surface AI, when it is not necessary to particularly distinguish the interposer first side surface BI1and the interposer second side surface BI2from each other, they are collectively referred to as an interposer side surface BI, and when it is not necessary to particularly distinguish the interposer first end surface CI1and the interposer second end surface CI2from each other, they are collectively referred to as an interposer end surface CI.

The multilayer body2preferably includes rounded corner portions R1and rounded ridge portions R2. The corner portions R1are each a portion at which the multilayer body main surface AS, the multilayer body side surface BS, and the multilayer body end surface CS intersect. The ridge portions R2are each a portion at which two surfaces of the multilayer body2intersect, i.e., the multilayer body main surface AS and the multilayer body side surface BS intersect, the multilayer body main surface AS and the multilayer body end surface CS intersect, or the multilayer body side surface BS and the multilayer body end surface CS intersect.

The multilayer body2includes the inner layer portion11, outer layer portions12respectively provided close to the main surfaces of the inner layer portion11, and side gap portions30.

Inner Layer Portion11

The inner layer portion11includes the plurality of sets of dielectric layers14and the internal electrode layers15which are alternately laminated along the lamination direction T.

The dielectric layers14are each made of a ceramic material. As the ceramic material, for example, a dielectric ceramic including BaTiO3as a main component is used. Furthermore, as the ceramic material, a material may be used which is obtained by adding at least one sub components such as a Mn compound, an Fe compound, a Cr compound, a Co compound, a nickel compound, etc. to these main components.

The internal electrode layers15are preferably made of, for example, a metallic material such as nickel, Cu, Ag, Pd, a Ag—Pd alloy, Au, or the like.

Furthermore, the internal electrode layers15each include a plurality of first internal electrode layer15aand a plurality of second internal electrode layer15b. The first internal electrode layer15aand the second internal electrode layer15bare alternately provided.

When it is not necessary to distinguish between the first internal electrode layers15aand the second internal electrode layers15b, they are collectively referred to as an internal electrode layer15.

The internal electrode layers15each include an opposing portion152at which the first internal electrode layer15afaces the second internal electrode layer15b, and a lead-out portion151which extends from the opposing portion152toward one of the multilayer body end surfaces CS. An end of the lead-out portion151is exposed at the multilayer body end surface CS, and is electrically connected to the external electrode3.

The direction in which the lead-out portion151extends differs between the first internal electrode layer15aand the second internal electrode layer15b, and alternately extends to the multilayer body first end surface CS1and the multilayer body second end surface CS2.

Furthermore, charges are accumulated between the opposing portions152of the first internal electrode layer15aand the second internal electrode layer15badjacent to each other in the lamination direction T, such that the characteristics of the capacitor are provided.

The outer layer portions12are each made of the same material as the dielectric layers14of the inner layer portion11.

Side Gap Portion30

The side gap portions30are provided on both sides of the region of the multilayer body where the internal electrode layers15are provided, and close to the multilayer body side surfaces BS. The side gap portions30are integrally manufactured with the same material as the dielectric layers14.

The external electrodes3are provided on the multilayer body end surfaces CS on both sides of the multilayer body2. The external electrodes3cover not only the multilayer body end surface CS, but also portions close to the multilayer body end surface CS, of the multilayer body main surface AS and the multilayer body side surface BS. As described above, the end portions of the lead-out portions151of the internal electrode layers15are each exposed to the multilayer body end surface CS, and electrically connected to the external electrode3.

Structure of External Electrode3

As shown inFIG.2, the external electrodes3each include, for example, a copper electrode layer31, a conductive resin layer32provided on the outside of the copper electrode layer31, a nickel-plated layer33provided on the outside of the conductive resin layer32, and a tin-plated layer34on the outside of the nickel-plated layer33.

The copper electrode layer31is provided, for example, by applying and firing a conductive paste including a conductive metal and glass. As shown inFIG.2, the copper electrode layer31covers not only the multilayer body end surface CS on both sides of the multilayer body2, but also extends to the multilayer body main surface AS, and covers a portion of the multilayer body main surface AS close to the multilayer body end surface CS.

The conductive resin layer32is provided on the outside of the copper electrode layer31to cover the copper electrode layer31. The conductive resin layer32may include any configuration including a thermosetting resin and a metal component, for example. As specific examples of the thermosetting resin, various known thermosetting resins such as epoxy resin, phenolic resin, urethane resin, silicone resin, polyimide resin, and the like can be used. As the metal component, for example, Ag can be used, or a metal powder coated with Ag on the surface of the base metal powder can be used.

Since the conductive resin layer32includes a thermosetting resin, it is more flexible than the copper electrode layer31made of, for example, a plating film or a fired product of a conductive paste. Therefore, even when an impact caused by physical shock or thermal cycling of the multilayer ceramic capacitor1is applied, the conductive resin layer32defines and functions as a buffer layer. Therefore, the conductive resin layer32reduces or prevents cracks in the multilayer ceramic capacitor1from occurring, easily absorbs piezoelectric vibration, and thus reduces or prevents “acoustic noise”.

A gap35is provided between the copper electrode layer31and the conductive resin layer32. In the gap35, a distance d in the length direction L between the copper electrode layer31and the conductive resin layer32is longest in the middle portion in the width direction W and the lamination direction T at the multilayer body end surface CS on which the copper electrode layer is provided. Furthermore, the distance between the copper electrode layer31and the conductive resin layer32becomes shorter approaching the end portion of the multilayer body end surface CS, i.e., approaching the multilayer body main surface AS or the multilayer body side surface BS. Moreover, the gap35is eliminated or substantially eliminated at the corner portion R1and the ridge portion R2, such that the copper electrode layer31and the conductive resin layer32are in contact with each other.

Thus, since the distance d in the length direction L of the gap35is longest in the middle portion in the width direction W and the lamination direction T at the multilayer body end surface CS, the external electrode3has a shape that bulges in the length direction L.

Similarly to the copper electrode layer31, the conductive resin layer32extends not only to the multilayer body end surface CS on both sides of the multilayer body2, but also to the multilayer body main surface AS, and also covers a portion of the multilayer body main surface AS close to the multilayer body end surface CS.

However, the conductive resin layer32terminates at a location closer to the multilayer body end surface CS on the multilayer body main surface AS in the length direction L than the copper electrode layer31is. That is, the length of the conductive resin layer32extending to the multilayer body main surface AS is equal to or less than the length of the copper electrode layer31extending to the multilayer body main surface AS.

The nickel-plated layer33is provided on the outside of the conductive resin layer32to cover the conductive resin layer32. The nickel-plated layer33is made of plating of nickel or an alloy including nickel, for example.

Similarly to the copper electrode layer31, the nickel-plated layer33extends not only to the multilayer body end surface CS on both sides of the multilayer body2, but also to the multilayer body main surface AS, and also covers a portion of the multilayer body main surface AS close to the multilayer body end surface CS. The nickel-plated layer33extends beyond the conductive resin layer32and to the same or substantially the same position as the copper electrode layer31on the multilayer body main surface AS.

Here, similarly to the copper electrode layer31, the conductive resin layer32extends not only to the multilayer body end surface CS on both sides of the multilayer body2, but also to the multilayer body main surface AS, and covers a portion of the multilayer body main surface AS close to the multilayer body end surface CS. However, the conductive resin layer32does not extend to the multilayer body main surface AS much as the copper electrode layer31extends to the multilayer body main surface AS.

Therefore, the external electrodes3each include a bulge portion36provided therein. The bulge portion36is provided such that a portion at which the conductive resin layer is provided bulges in the lamination direction T on the multilayer body main surface AS when viewed from the outside of the nickel-plated layer33.

A tin-plated layer34is provided on the outside of the nickel-plated layer33. The tin-plated layer34is made of plating of an alloy including tin or tin, for example. As described later, in a state in which the interposer4is attached to the nickel-plated layer33, the tin-plated layer34covers the outside including a protrusion40to be described later of the interposer4, except for a non-plated region45thereof.

It should be noted that the plated layer of tin or an alloy including tin in the present preferred embodiment includes a single layer of the tin-plated layer34. However, the present invention is not limited thereto, and may include a structure including two tin-plated layers including another tin-plated layer which covers the nickel-plated layer33without covering the interposer4between the nickel-plated layer33and the tin-plated layer34.

Size of Capacitor Main Body1A

The capacitor main body1A in the present preferred embodiment has the three sizes of type A, type B, and type C.FIG.4is a table showing favorable ranges for each of the types of the capacitor main body1A.

Type A

The ranges for a Type-A of the capacitor main body1A are as follows, as shown in the table.

Dimension in length direction L: about 0.95 mm to about 1.15 mm

Dimension in width direction W: about 0.62 mm to about 0.68 mm

Dimension in lamination direction T: about 0.62 mm to about 0.68 mm

Dimension in the lamination direction T of the dielectric layer14: about 0.98 mm to about 1.09 μm

Dimension in the lamination direction T of the internal electrode layer15: about 0.62 mm to about 0.68 μm

Number of layers of each of the dielectric layers14and the internal electrode layers15: 350 to 380

Dimension in the lamination direction T of the outer layer portion12: about 17 μm to about 23 μm

Deviation amount in the length direction L of the internal electrode layers15: about 45 μm to about 48 μm

Dimension in the width direction W of the side gap portion30: about 32 μm to about 42 μm

The deviation amount in the length direction L of the internal electrode layers15corresponds to the lengths of the respective lead-out portions151of the first internal electrode layer15aand the second internal electrode layer15bwhich are alternately provided.

Type B

The ranges for a type-B of the capacitor main body1A are as follows, as shown in the table.

Dimension in length direction L: about 1.62 mm to about 1.72 mm

Dimension in width direction W: about 0.88 mm to about 0.96 mm

Dimension in lamination direction T: about 0.89 mm to about 0.97 mm

Dimension in the lamination direction T of the dielectric layer14: about 1.35 μm to about 1.45 μm

Dimension in the lamination direction T of the internal electrode layer15: about 0.67 μm to about 0.77 μm

Number of layers of each of the dielectric layers14and the internal electrode layers15: 386 to 426

Dimension in the lamination direction T of the outer layer portion12: about 35 μm to about 45 μm

Deviation amount in the length direction L of the internal electrode layer15: about 72 μm to about 78 μm

Dimension in the width direction W of the side gap portion30: about 52 μm to about 62 μm

Type C

The ranges for the type C of the capacitor main body1A are as follows, as shown in the table.

Dimension in the length direction L: about 1.81 mm to about 2.01 mm

Dimension in width direction W: about 1.29 mm to about 1.49 mm

Dimension in lamination direction T: about 1.32 mm to about 1.42 mm

Dimension in the lamination direction T of the dielectric layer14: about 1.88 μm to about 1.96 μm

Dimension in the lamination direction T of the internal electrode layer15: about 0.73 μm to about 0.86 μm

Number of layers of each of the dielectric layer14and the internal electrode layer15: 440 to 490

Dimension in the lamination direction T of the outer layer portion12: about 52 μm to about 63 μm

Deviation amount in the length direction L of the internal electrode layer15: about 72 μm to about 85 μm

Dimension in the width direction W of the side gap portion30: about 63 μm to about 75 μm

FIG.5is a view of the multilayer ceramic capacitor1viewed from the side on which an interposer4is provided.FIG.6is a perspective view of the interposer4. The interposer4includes a pair of the first interposer4A and the second interposer4B. Hereinafter, when it is not necessary to distinguish between the first interposer4A and the second interposer4B, they are referred to as an interposer.

On the capacitor second main surface AC2of the capacitor main body1A, the first interposer4A is provided adjacent to the capacitor first end surface CC1in the length direction L, and the second interposer4B is provided adjacent to the other capacitor second end surface CC2in the length direction L. The first interposer4A and the second interposer4B have the same or substantially the same shape, are opposed to each other, and are spaced apart from each other by a predetermined distance.

The first interposer4A is spaced apart from the second interposer4B. However, they are connected by an insulation member50, such as a resin member, for example.

Shape of Interposer4

The interposer4is made of a material including copper or a copper alloy, for example, and has a shape in which a plurality of recess portions are provided in a rectangular or substantially rectangular parallelepiped block portion.

A third recess portion43is provided on the interposer first end surface CI1of the interposer4, such that the protrusion40is provided. Therefore, the interposer first end surface CI1includes a flat tip surface40aof a tip of the protrusion40, and a curved surface of the third recess portion43.

A first recess portion41and second recess portions42are provided on the interposer second end surface CI2of the interposer4. The interposer second end surface CI2includes the two curved surfaces of the first recess portion41and the second recess portions42.

The third recess portion43has a shape in which the ridge portion between the interposer first end surface CI1and the interposer second main surface AI2is cut by a curved surface.

By providing the third recess portion43, the protrusion40protruding in the length direction L is provided over the entire or substantially the entire length in the width direction W on the interposer first end surface CI1close to the capacitor second main surface AC2. The protrusion40extends from one interposer4toward the other interposer4.

The length LI shown inFIGS.5and6in which the protrusion40extends in the length direction L from the interposer second main surface AI2is about 50 μm or more and about 100 μm or less.

Advantageous Effects of Protrusion40

There is a gap between the multilayer ceramic capacitor1including the interposer4and the board due to the interposer4. Therefore, when the board is distorted, the multilayer ceramic capacitor1may be bent at the portion not in contact with the interposer4.

However, in the multilayer ceramic capacitor1of the present preferred embodiment, the protrusion40is provided in the interposer4, and the upper side of the protrusion40is a flat surface that continues flush from the interposer first main surface AI1.

Therefore, the contact area between the capacitor second main surface AC2of the capacitor main body1A, and the interposer first main surface AI1of the interposer4is increased by the protrusion40. Therefore, in the multilayer ceramic capacitor1, the bending strength is improved, and the possibility of being bent is reduced.

First Recess Portion41

As shown inFIGS.5and6, the interposer4includes the first recess portion41on the interposer second end surface CI2in a certain area around the middle portion in the width direction W.

The first recess portion41further includes an upper first recess portion41aadjacent to the interposer first main surface AI1, and a lower first recess portion41badjacent to the interposer second main surface AI2. The upper first recess portion41aand the lower first recess portion41bare continuous in the lamination direction T.

When viewed inFIG.5, the inner surfaces of the upper first recess portion41aand the lower first recess portion41beach have, for example, an elliptical or substantially elliptical arc shape or an arcuate or substantially arcuate shape, and when viewed from the cross section inFIG.2, each include an elliptical or substantially elliptical arc shape or an arcuate or substantially arcuate shape, i.e., include a first curved surface. Thus, since the inner surfaces of the upper first recess portion41aand the lower first recess portion41beach include a curved surface, it is possible to reduce or prevent solder from rising more efficiently.

Advantageous Effects of First Recess Portion41

Such a configuration of the first recess portion41provides the following advantageous effects.

A solder is used when mounting the multilayer ceramic capacitor1including the interposer4on a mounting board. At this time, if a surplus solder is present, there is a possibility that the solder protrudes on the outside of the interposer4. However, when the first recess portion41is provided as in the present preferred embodiment, since the surplus solder is accommodated in the first recess portion41, the possibility of the solder protruding on the outside of the interposer4is reduced.

Furthermore, since the first recess portion41includes a two-stage structure, first, the surplus solder fills the lower first recess portion41b, and if surplus solder is still present, the surplus solder goes beyond the boundary between the lower first recess portion41band the upper first recess portion41a, and reaches the first recess portion41a.

In other words, the solder connecting the mounting board and the interposer4hardly rises up to the upper side. Therefore, since the mounting board and the capacitor main body1A are connected by the solder, the possibility of generating acoustic noise is reduced.

Furthermore, as shown inFIG.2and as described above, when the capacitor main surface AC is viewed from the outside of the nickel-plated layer33, the external electrodes3each include the bulge portion36in which a portion at which the conductive resin layer32is provided bulges in the lamination direction T.

The bulge portion36has a dimension to fit in the first recess portion41in a cross section passing through the middle in the width direction W of the multilayer ceramic capacitor1shown inFIG.2.

Advantageous Effects Derived from Bulge Portion36Being Fit in First Recess Portion41

For example, if the bulge portion36is not provided when a force is applied to a mounting board and a distortion is caused, the ridge portion between the interposer first end surface CI1and the interposer first main surface AI1in the interposer4presses the capacitor second main surface AC2, such that the stress is concentrated on the pressed portion in the capacitor main body1A.

However, when the bulge portion36is provided, in the capacitor main body1A, the stress is easily applied to the side end portion of the bulge portion36close to the interposer second end surface CI2. Therefore, portions at which the stress is concentrated in the capacitor main body1A are dispersed, such that the bending strength of the capacitor main body1A is improved.

As shown inFIG.6, the interposer4includes the second recess portions42on both sides of the first recess portion41in the width direction W on the interposer second end surface CI2. The second recess portions42are each about ±10% of a half of the thickness of the interposer4in the lamination direction T. When viewed from the interposer side surface BI, the inner surfaces of the second recess portions42each have an elliptical or substantially elliptical arc shape or an arcuate or substantially arcuate shape, i.e., a second curved surface. Thus, since the inner surfaces of the second recess portions42each have a curved surface, it is possible to reduce or prevent the solder from rising more efficiently.

Advantageous Effects of Second Recess Portion42

Such a configuration of the second recess portions42causes the solder connecting the mounting board and the interposer4to hardly rise up immediately to the upper side. Therefore, since the mounting board and the capacitor main body1A are connected by the solder, the possibility of generating acoustic noise is reduced.

As shown inFIG.2, the nickel-plated layer44is provided on the outer periphery of the interposer4. The nickel-plated layer44does not cover a portion at which the insulation member50connecting the first interposer4A and the second interposer4B is present, i.e., a portion of the upper side of the tip face40aof the protrusion40adjacent to the interposer first main surface AI1and adjacent to the capacitor main body1A. This portion corresponds to the non-plated region45. The tip surface40aof the protrusion40includes the non-plated region45on the upper side, and a plated region46on the lower side.

Joining Between Interposer4and Capacitor Main Body1A

Furthermore, the interposer first main surface AI1, which is an upper surface of the interposer4and to which the nickel-plated layer44is applied, is joined with the capacitor second main surface AC2, which is a lower surface of the capacitor main body1A, by the nickel-plated layer33of the external electrode3and a solder H.

Tin Plating of Interposer4and External Electrode3

The tin-plated layer34is further provided on the outer periphery of the external electrode3of the capacitor main body1A and the interposer4. The tin-plated layer34does not cover a portion at which the insulation member50connecting the first interposer4A and the second interposer4B is present, i.e., the non-plated region45at which the nickel-plated layer44of the protrusion40is not provided.

In other words, similarly to the nickel-plated layer44, the tin-plated layer34does not cover a portion of the upper side of the tip surface40aof the protrusion40close to the interposer first main surface AI1, i.e., the non-plated region45close to the capacitor main body1A.

Advantageous Effects Derived from Tin-Plated Layer34not being Provided in Non-Plated Region45

In the portion at which the insulation member50connecting the first interposer4A and the second interposer4B is not present, it is not possible for the solder to rise. Therefore, the possibility of generating acoustic noise due to the solder connecting the mounting board and the capacitor main body1A is reduced.

Plating on Surface of Recess Portion

The surface of each of the recess portions of the interposer4is covered with the nickel-plated layer44and the tin-plated layer34.

Placement Position of Interposer

As described above, the interposer first main surface AI1, which is an upper surface of the interposer4, is joined with the capacitor second main surface AC2, which is a lower surface of the capacitor main body1A, by the external electrode3and the solder H.

As shown inFIG.5, the dimension in the width direction W of the interposer is smaller than the dimension in the width direction W of the capacitor main body1A. Here, when assuming that, the distance in the width direction W between the interposer first side surface BI1and the capacitor first side surface BC1of the first interposer4A is defined as X1as shown in the lower right side in the drawings, the distance in the width direction W between the interposer second side surface BI2and the capacitor first side surface BC1of the second interposer4B is defined as X2as shown in the lower left side in the drawings; the distance in the width direction W between the interposer first side surface BI1and the capacitor second side surface BC2of the second interposer4B is defined as X3as shown in the upper left side in the drawings, and the distance in the width direction W between the interposer second side surface BI2and the capacitor second side surface BC2of the first interposer4A is defined as X4as shown in the upper right side inFIG.5, X2>X3and X1>X4are satisfied.

In other words, in the multilayer ceramic capacitor1, as viewed from the lower surface, i.e., in a plan view as viewed from the capacitor second main surface AC2, the interposer4with respect to the capacitor main body1A satisfies the relationships of X2>X3and X1>X4. Therefore, the interposer4is positioned to be biased in the width direction W with respect to the capacitor main body1A.

However, the slope of the center line passing through the center in the width direction W of each of the first interposer4A and the second interposer4B and extending in the length direction L with respect to the center line passing through the middle in the width direction W of the capacitor main body1A and extending in the length direction L is X1/X4*0.9<X2/X3<X1/X4*1.1. Therefore, the slope angle is small, and thus, both the center lines are substantially parallel to each other.

However, the present invention is not limited thereto, and may satisfy X2=X3and X1=X4.

Alternatively, the present invention may satisfy X2=X3=X1=X4.

It should be noted that any one of X1, X2, X3, and X4is, for example, about 20 μm or less.

Advantageous Effects Derived from X2>X3and X1>X4

Thus, since the multilayer ceramic capacitor1of the present preferred embodiment satisfies X2>X3and X1>X4, it is possible to provide the multilayer ceramic capacitor1in which the mounting orientation of the multilayer ceramic capacitor1to the board is identifiable when mounted on the board. Therefore, when a specific mounting orientation relative to the board is required to be identified, it is possible to easily identify the orientation.

Method of Manufacturing Multilayer Ceramic Capacitor1

Next, a non-limiting example of a method of manufacturing the multilayer ceramic capacitor1according to the present preferred embodiment will be described.FIG.7is a flowchart explaining a method of manufacturing the multilayer ceramic capacitor1.

The manufacturing process of the multilayer ceramic capacitor1includes a multilayer body manufacturing step S1, an external electrode forming step S2, and an interposer mounting step S3.

Multilayer Body Manufacturing Step S1

First, a material sheet is provided in which a pattern of the internal electrode layers15is printed with a conductive paste onto a lamination ceramic green sheet molded in a sheet shape with a ceramic slurry.

Then, a plurality of material sheets are stacked such that the internal electrode patterns become shifted (offset) by about a half pitch in the length direction between adjacent material sheets.

Furthermore, ceramic green sheets for the outer layer portion defining and functioning as the outer layer portions are stacked on both sides of the stacked material sheets, such that a mother block member is formed by, for example, thermocompression bonding.

The mother block member is divided along the cutting line corresponding to the dimension of the multilayer body, such that a plurality of multilayer bodies2are manufactured.

External Electrode Forming Step S2

Next, the copper electrode layer31, the conductive resin layer32, and the nickel-plated layer33are sequentially formed at both end portions of the multilayer body2, such that the external electrodes3are formed.

The copper electrode layer31is formed, for example, by applying and firing a conductive paste containing a conductive metal and glass. As shown inFIG.2, the copper electrode layer31extends not only to the multilayer body end surface CS on both sides of the multilayer body2, but also to the multilayer body main surface AS, and covers a portion of the multilayer body main surface AS close to the multilayer body end surface CS.

The conductive resin layer32is formed on the outside of the copper electrode layer31to cover the copper electrode layer31. At this time, the length of the conductive resin layer32extending to the multilayer body main surface AS is, for example, equal to or less than the length of the copper electrode layer31extending to the multilayer body main surface AS.

Thus, since the conductive resin layer32does not extend to the multilayer body main surface AS as much as the copper electrode layer31extends to the multilayer body main surface AS, when viewed from the outside of the nickel-plated layer33, the external electrode3includes the bulge portion36provided therein. The bulge portion36is provided such that a portion at which the conductive resin layer32is provided bulges in the lamination direction T on the multilayer body main surface AS.

Furthermore, the gap35is provided between the copper electrode layer31and the conductive resin layer32. The gap35is provided such that the distance d in the length direction L becomes longest in the middle portion in the width direction W and the lamination direction T at the multilayer body end surface CS, such that the external electrode3bulges in the length direction L.

The nickel-plated layer33is formed on the outside of the conductive resin layer32to cover the conductive resin layer32.

The length of the nickel-plated layer33extending to the multilayer body main surface AS exceeds the length of the conductive resin layer32, and is the same or substantially the same as the length of the copper electrode layer31extending to the multilayer body main surface AS.

Then, heating is performed at a set firing temperature in a nitrogen atmosphere. Thus, the external electrodes3are fired to the multilayer body2, such that the capacitor main body1A is manufactured.

FIGS.8A to8Hprovide diagrams illustrating an interposer mounting step S3. InFIGS.8A to8H, the views shown on the upper side are top views, and the views shown on the lower side are side views. The interposer mounting step S3includes an interposer manufacturing step S31, an interposer connecting step S32, a nickel plating step S33, a holding step S34, a connecting material providing step S35, a capacitor placing step S36, a holding portion removing step S37, and a tin plating step S38to be described below.

As shown inFIG.8Aand described above, a pair of the first interposer4A and the second interposer4B are manufactured, for example, by cutting rectangular or substantially rectangular parallelepiped blocking members made of copper, and forming the protrusions40, the first recess portions41, and the second recess portions42and the third recess portions43.

As shown inFIG.8B, a pair of the first interposer4A and the second interposer4B are connected via the insulation member50. The insulation member50is, for example, a plate-shaped glass epoxy. However, the present invention is not limited thereto, and the insulation member50may be manufactured by other insulation members.

The insulation member50is attached to the portion of the upper side of the tip of the protrusion40on the interposer first end surface CI1of each of the pair of the first interposer4A and the second interposer4B. The portion of the upper side of the tip of the protrusion40is adjacent to the interposer first main surface AI1.

The length of the insulation member50corresponds to the distance between the two external electrodes3provided on both sides of the multilayer body2. As shown inFIG.1, the distance between the two external electrodes3is a distance L2between the end portion of one of the external electrodes3extending to the multilayer body side surface BS and the end portion of the other of the external electrodes3extending to the multilayer body side surface BS.

Nickel Plating Step S33

As shown inFIG.8C, the first interposer4A and the second interposer4B are subjected to a nickel plating process to form the nickel-plated layer44. At this time, the nickel-plated layer44is not formed on the insulation member50.

Holding Step S34

As shown inFIG.8D, the first interposer4A and the second interposer4B on which the nickel-plated layer44is formed, and the insulation member50connecting them are provided on a holding portion51, and fixed. The holding portion51includes a flat surface such as, for example, a sheet member or a plate-shaped plate member.

When joining the first interposer4A and the second interposer4B to the capacitor main body1A subsequently, the holding portion51defines and functions as a pedestal to hold the first interposer4A and the second interposer4B in place at a predetermined position.

Although not included in the present preferred embodiment, an insulation member removing step may be provided between the holding step S34and the subsequent connecting member providing step S35. In the insulation member removing step, the insulation member50is removed by separating the insulation member50from the first interposer4A and the second interposer4B. Then, the portion at which the insulation member50is cut, at the tip of the protrusion40of the interposer4, becomes the non-plated region45of nickel plating.

Connecting Material Providing Step S35

As shown inFIG.8E, for example, a cream solder H as an example of a connecting material for the connection between the interposer4and the external electrode is provided on the interposer4by, for example, screen printing or the like.

Capacitor Placing Step S36

As shown inFIG.8F, the capacitor main body1A is placed on the first interposer4A and the second interposer4B which are fixed on the holding portion51.

Advantageous Effects Derived from Being Held by Insulation Member50

Here, the distance between the first interposer4A and the second interposer4B on the holding portion51is the length of the insulation member50connecting them.

Therefore, when the capacitor main body1A is placed on the first interposer4A and the second interposer4B, the first interposer4A is placed below one of the external electrodes3, and the second interposer4B is placed below the other external electrode3.

Therefore, it is possible to easily perform the positioning of the first interposer4A and the second interposer4B with respect to the external electrodes3.

Holding Portion Removing Step S37

As shown inFIG.8G, the holding portion51is removed from the article molded by the interposer4and the external electrodes3of the capacitor main body1A being connected by the solder H.

Tin Plating Step S38

As shown inFIG.8H, the tin-plated layer34is formed on the article in which the capacitor main body1A is connected on the interposer4and the holding portion51is removed.

Here, since the insulation member50is present at the portion on the upper side of the tip of the protrusion40on the interposer first end surface CI1adjacent to the interposer first main surface AI1, such a portion corresponds to the non-plated region45which is not covered with the nickel-plated layer44, and the tin-plated layer34is not formed.

Thus, the multilayer ceramic capacitor1shown inFIG.1is manufactured, followed by being mounted on the mounting board.

FIG.9is a partial cross-sectional view of the multilayer ceramic capacitor1corresponding toFIG.2in a case in which the insulation member removing step is provided between the holding step S34and the connecting material providing step S35, such that the insulation member50is removed. Even if the insulation member50is removed, since the removed portion does not include the nickel-plated layer44provided thereon, the tin-plated layer34is not formed in the tin plating step S38. Therefore, the non-plated region45is present at the portion on the upper side of the tip face40aof the protrusion40adjacent to the interposer first main surface AI1, i.e., adjacent to the capacitor main body1A.

During the mounting, since the two interposers4are connected by the insulation member50, the solder does not rise up to the capacitor main body1A beyond the insulation member50. Therefore, the capacitor main body1A is in no way connected to the board by the solder, such that the possibility of generating “acoustic noise” is reduced or prevented.

Furthermore, since neither of the nickel-plated layer44and the tin-plated layer34is formed in the non-plated region45in which the insulation member50is present, it is possible to reduce ESR (transmission series resistance) as the multilayer ceramic capacitor1.

Furthermore, in the multilayer ceramic capacitor1according to the present preferred embodiment, as viewed from the lower surface, i.e., in a plan view as viewed from the capacitor second main surface AC2, the interposer4with respect to the capacitor main body1A satisfies the relationships of X2>X3and X1>X4.

Therefore, the interposer4is biased in the width direction W with respect to the capacitor main body1A.

Therefore, when viewed from the lower surface, it is possible to identify the direction in the width direction W of the multilayer ceramic capacitor1. Therefore, it is possible to choose the direction in the width direction W at the time of mounting on the board.

Modified Example

While preferred embodiments of the present invention have been described above, the present invention is not limited thereto.

In the above-described preferred embodiments, the interposer4is mounted parallel or substantially parallel to the capacitor main body1A. That is, the respective interposer main surfaces AI of the first interposer4A and the second interposer4B are parallel or substantially parallel to each other, and located on the same or substantially the same horizontal plane. Then, the respective interposer main surfaces AI of the first interposer4A and the second interposer4B are parallel or substantially parallel to the capacitor main surface AC and the multilayer body main surface AS.

However, the present invention is not limited to this, and the respective interposer main surfaces AI of the first interposer4A and the second interposer4B may not be parallel or substantially parallel to each other. Furthermore, the respective interposer main surfaces AI of the first interposer4A and the second interposer4B may not be parallel or substantially parallel to the capacitor main surface AC or the multilayer body main surface AS.

FIGS.10and11are diagrams for explaining modified examples, and show a mode in which the interposer main surface AI of the first interposer4A and the interposer main surface AI of the second interposer4B are not parallel or substantially parallel to each other, and the interposer main surfaces AI of the first interposer4A and the second interposer4B are sloped with respect to the capacitor main surface AC and the multilayer body main surface AS, respectively.

First Modified Example

FIG.10is a diagram showing a first modified example of a preferred embodiment of the present invention.

As shown inFIG.10, in the first modified example, the first interposer4A and the second interposer4B include the interposer first main surface AI1and the interposer second main surface AI2opposite thereto, respectively, and the interposer first main surface AI1and the interposer second main surface AI2are parallel or substantially parallel to each other. Then, the interposer first main surface AI1is sloped at a predetermined angle so as to approach the capacitor second main surface AC2toward the opposed interposer on the other side. In other words, it has an inverted “V” shape. The predetermined angle is preferably about 10 degrees or less, for example.

Such a multilayer ceramic capacitor1can be manufactured by providing the solder H to be biased adjacent to the interposer second end surface CI2on the interposer main surface AI when joining the interposer4and the capacitor main body1A in the state ofFIGS.8A to8Hdescribed above, for example.

Advantageous Effects

The interposer second main surface AI2of the first interposer4A, and the interposer second main surface AI2of the second interposer4B correspond to a mounting surface to the board of the multilayer ceramic capacitor1.

Here, if this mounting surface is flat, when mounted on the board, there is a possibility that the multilayer ceramic capacitor1will slide laterally with respect to the board, such that positioning in the horizontal direction is difficult. This may lead to a case in which the mounting posture becomes unstable.

However, according to the present modified example, the interposer second main surface AI2of the first interposer4A and the interposer second main surface AI2of the second interposer4B defining and functioning as the mounting surfaces are sloped in opposite directions to each other so as to have an inverted “V” shape. Therefore, the multilayer ceramic capacitor1is difficult to move to the left and right, such that the mounting posture is stabilized by the self-alignment effect.

Second Modified Example

FIG.11is a diagram showing a second modified example of a preferred embodiment of the present invention.

As shown inFIG.11, in the second modified example, the first interposer4A and the second interposer4B include the interposer first main surface AI1and the interposer second main surface AI2opposite thereto, respectively, and the interposer first main surface AI1and the interposer second main surface AI2are parallel or substantially parallel to each other. Then, the interposer first main surface AI1is sloped at a predetermined angle so as to be spaced away from the capacitor second main surface AC2toward the opposed interposer on the other side. In other words, it has a “V” shape. The predetermined angle is preferably about 10 degrees or less, for example.

Such a multilayer ceramic capacitor1can be manufactured by providing the solder H to be biased adjacent to the interposer first end surface CI1on the interposer main surface AI when joining the interposer4and the capacitor main body1A in the state ofFIGS.8A to8Hdescribed above, for example.

Advantageous Effects

The interposer second main surface AI2of the first interposer4A, and the interposer second main surface AI2of the second interposer4B correspond to a mounting surface to the board of the multilayer ceramic capacitor1.

Here, if the mounting surface is flat, when mounted on the board, there is a possibility that the multilayer ceramic capacitor1slides laterally with respect to the board, such that positioning in the horizontal direction is difficult. This may lead to a case in which the mounting posture becomes unstable.

However, according to the present modified example, the interposer second main surface AI2of the first interposer4A and the interposer second main surface AI2of the second interposer4B defining and functioning as the mounting surfaces are sloped in opposite directions to each other so as to have a “V” shape. Therefore, the multilayer ceramic capacitor1is difficult to move to the left and right, such that the mounting posture is stabilized by the self-alignment effect.