JP2017191880A - Multilayer ceramic electronic component and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer ceramic electronic component which suppresses explosion and non-wetting of solder that can occur on mounting caused by containing a thermosetting resin in an external electrode.SOLUTION: A multilayer ceramic capacitor 10 includes a laminate 20 formed into a rectangular parallelepiped by laminating a plurality of ceramic layers 30, a plurality of first internal electrode layers 40a and a plurality of second internal electrode layers 40b, a first external electrode 50 formed on the surface of the laminate 20 and a second external electrode 50b, where the first external electrode 50a and the second external electrode 50b includes a first conductive resin layer 54a and a second conductive resin layer 54b containing a thermosetting resin and a metal component, and a first plating layer 60a and a second plating layer 60b arranged on the surface of the first conductive resin layer 54a and the second conductive resin layer 54b, and a concentration of the metal component exposed to the surface of the conductive resin layer 54a and the second conductive resin layer 54b is 7% or more.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a multilayer ceramic electronic component and a method for manufacturing the same, and more particularly, to a multilayer ceramic electronic component including an external electrode containing a thermosetting resin and a method for manufacturing the same.

  In recent years, multilayer ceramic electronic components (for example, multilayer ceramic capacitors) have come to be used even in harsher environments than before. Therefore, it is required to withstand such use. For example, multilayer ceramic capacitors used in mobile devices such as mobile phones and portable music players are required not to crack and fall off the mounting board even when subjected to impacts due to dropping. In addition, a multilayer ceramic capacitor used in an in-vehicle device such as an EUC (Electronic Control Unit) has a mounting solder even if the mounting substrate receives a bending stress caused by thermal expansion and contraction due to a thermal cycle. In addition, no cracks are required. In response to such a demand, it has been proposed to form an external electrode using a thermosetting conductive paste instead of the conventional fired conductive paste. For example, Patent Document 1 discloses such a multilayer ceramic electronic component.

  The multilayer ceramic electronic component of Patent Document 1 is formed of a high melting point conductive particle, a thermosetting conductive paste containing a metal powder having a melting point of 300 ° C. or less and a resin, and if necessary, Ni plating is performed by electroplating, Thereafter, an external electrode on which solder plating or Sn plating is applied by electroplating is further provided.

International Publication No. 2004/053901

  As described above, the multilayer ceramic electronic component of Patent Literature 1 includes an external electrode including a thermosetting resin. A plating layer is preferably formed on such an external electrode in consideration of solderability. However, since the external electrode containing a thermosetting resin generally has a low concentration of metal components exposed on the surface, it is not possible to sufficiently secure the metal components that are the starting points for plating growth. For this reason, it becomes difficult to conduct | electrically_connect at the time of plating layer formation, and it may become difficult to form the plating layer of smooth and sufficient thickness. Thereby, solder non-wetting occurs at the time of mounting, and the mountability can be lowered. Further, since the Ni plating layer cannot sufficiently perform the function of preventing moisture intrusion with respect to the plating solution or the like, there has been a problem that the solder and the electrode material are scattered at the time of mounting, so-called solder explosion.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multilayer ceramic electronic component in which the explosion and non-wetting of solder that may occur during mounting due to the thermosetting resin being included in the external electrode is suppressed.
Another object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component in which the explosion and non-wetting of solder that may occur during mounting due to the inclusion of a thermosetting resin in the external electrode is suppressed. .

The multilayer ceramic electronic component according to the present invention is formed in a rectangular parallelepiped shape by alternately laminating a plurality of ceramic layers and a plurality of internal electrode layers, and a pair of main surfaces opposed in the laminating direction and in the laminating direction A laminated body including a pair of side faces opposed in the orthogonal width direction and a pair of end faces opposed in the lamination direction and the length direction orthogonal to the width direction, and a plurality of internal electrodes formed on the surface of the laminated body A multilayer ceramic electronic component comprising a pair of external electrodes electrically connected to a layer, each of the pair of external electrodes comprising a conductive resin layer containing a thermosetting resin and a metal component, and a conductive resin layer And a metal component concentration exposed on the surface of the conductive resin layer is 7% or more.
Preferably, each of the pair of external electrodes further includes a base electrode layer that is disposed between the laminate and the conductive resin layer and includes metal and glass.
A manufacturing method of a multilayer ceramic electronic component according to the present invention is formed in a rectangular parallelepiped shape by alternately laminating a plurality of ceramic layers and a plurality of internal electrode layers, and a pair of main surfaces opposed in the laminating direction; By forming on the surface of the laminate, a laminate including a pair of side surfaces opposed in the width direction perpendicular to the lamination direction, and a pair of end faces opposed in the lamination direction and the length direction perpendicular to the width direction. A method for manufacturing a multilayer ceramic electronic component comprising a pair of external electrodes electrically connected to a plurality of internal electrode layers, wherein the plurality of ceramic layers and the plurality of internal electrode layers are alternately stacked. Preparing a conductive resin layer by applying a paste containing a thermosetting resin and a metal component to the surface of the laminate and curing the paste, and the conductive resin layer. And a step of performing an oxygen plasma treatment, in the step of performing an oxygen plasma treatment to remove the resin on the surface of the conductive resin layer, and wherein the exposing the metal components on the surface of the conductive resin layer.

According to the present invention, it is possible to provide a multilayer ceramic electronic component in which the explosion and non-wetting of solder that may occur during mounting due to the thermosetting resin being included in the external electrode is suppressed.
In addition, according to the present invention, it is possible to manufacture a multilayer ceramic electronic component in which the explosion and non-wetting of solder that may occur during mounting due to the thermosetting resin contained in the external electrode is suppressed.

  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 a multilayer ceramic capacitor according to an embodiment of the present invention. It is II-II sectional drawing of FIG. 1 which shows the laminated ceramic capacitor which concerns on one embodiment of this invention. It is a schematic diagram just before performing the oxygen plasma process at the time of manufacturing the multilayer ceramic capacitor which concerns on one embodiment of this invention. It is a schematic diagram immediately after the oxygen plasma process at the time of manufacturing the multilayer ceramic capacitor which concerns on one embodiment of this invention is performed.

1. Multilayer Ceramic Capacitor Hereinafter, a multilayer ceramic capacitor which is a multilayer ceramic electronic component according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an external perspective view showing a multilayer ceramic capacitor according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II of FIG. 1 showing a multilayer ceramic capacitor according to an embodiment of the present invention. The multilayer ceramic capacitor 10 according to this embodiment includes a multilayer body 20, and a first external electrode 50a and a second external electrode 50b (a pair of external electrodes) disposed on the surface of the multilayer body 20.

(Laminated body 20)
The multilayer body 20 is formed in a rectangular parallelepiped shape by alternately laminating a plurality of ceramic layers 30, a plurality of first internal electrode layers 40a, and a plurality of second internal electrode layers 40b. That is, the stacked body 20 includes a first main surface 22a and a second main surface 22b (a pair of main surfaces) opposed in the stacking direction (hereinafter referred to as “T direction”) and a width direction (hereinafter referred to as “T direction”). The first side surface 24a and the second side surface 24b (a pair of side surfaces) facing each other in the “W direction”) and the first side surface facing the length direction (hereinafter referred to as the “L direction”) orthogonal to the T direction and the W direction. 1 end surface 26a and 2nd end surface 26b (a pair of end surface). Here, the rectangular parallelepiped shape of the stacked body 20 includes the first main surface 22a and the second main surface 22b, the first side surface 24a and the second side surface 24b, the first end surface 26a and the second end surface. 26b and the overall shape. For example, the corners and ridges of the laminate 20 are preferably rounded. Further, the first main surface 22a and the second main surface 22b, the first side surface 24a and the second side surface 24b, and the first end surface 26a and the second end surface 26b are partially or entirely uneven. It may be formed.

The ceramic layer 30 is sandwiched between the first internal electrode layer 40a and the second internal electrode layer 40b and laminated in the T direction. As the ceramic material of the ceramic layer 30, for example, a dielectric ceramic made of a main component such as BaTiO ₃ , CaTiO ₃ , SrTiO ₃ , CaZrO ₃ can be used. In addition, subcomponents such as a Mn compound, Fe compound, Cr compound, Co compound, and Ni compound may be added to these main components. In addition, it is preferable that the thickness of the ceramic layer 30 is 0.5 micrometer or more and 10 micrometers or less.

  The first internal electrode layer 40 a extends in a flat plate shape at the interface of the ceramic layer 30, and an end portion thereof is exposed at the first end surface 26 a of the multilayer body 20. On the other hand, the second internal electrode layer 40b extends in a flat plate shape at the interface of the ceramic layer 30 so as to face the first internal electrode layer 40a with the ceramic layer 30 interposed therebetween, and the end thereof is the second of the laminate 20. It is exposed at the end face 26b. Therefore, the first internal electrode layer 40 a has a facing portion that faces the second internal electrode layer 40 b through the ceramic layer 30, and a lead portion that is drawn to the first end surface 26 a of the multilayer body 20. Similarly, the second internal electrode layer 40b includes a facing portion that faces the first internal electrode layer 40a with the ceramic layer 30 interposed therebetween, and a lead portion that is drawn to the second end face 26b of the stacked body 20. . The opposing portion of the first internal electrode layer 40a and the opposing portion of the second internal electrode layer 40b are opposed to each other with the ceramic layer 30 therebetween, thereby generating electrostatic capacity. The first internal electrode layer 40a and the second internal electrode layer 40b are made of, for example, a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy containing at least one of these metals, for example, Ag- It is made of an appropriate conductive material such as a Pd alloy. The thickness of each of the first internal electrode layer 40a and the second internal electrode layer 40b is preferably about 0.2 μm or more and 2.0 μm or less, for example.

(First external electrode 50a and second external electrode 50b)
The first external electrode 50a is disposed on the first end surface 26a of the stacked body 20 so as to be electrically connected to the first internal electrode layer 40a, and is extended therefrom so as to extend from the first main surface 22a. The second main surface 22b, the first side surface 24a, and the second side surface 24b are arranged to reach a part of each. Note that the first external electrode 50 a may be disposed only on the first end surface 26 a of the multilayer body 20. On the other hand, the second external electrode 50b is electrically connected to the second internal electrode layer 40b by being disposed on the second end face 26b of the multilayer body 20, and is extended therefrom to be connected to the first main electrode 50b. The surface 22a, the second main surface 22b, the first side surface 24a, and the second side surface 24b are disposed so as to reach a part thereof. The second external electrode 50b may be disposed only on the second end surface 26b of the stacked body 20.

  The first external electrode 50a includes a first base electrode layer 52a disposed on the surface so as to cover the stacked body 20, and a first base electrode layer 52a disposed on the surface so as to cover the first base electrode layer 52a. 1 conductive resin layer 54a, and a first plating layer 60a disposed on the surface so as to cover the first conductive resin layer 54a. Similarly, the second external electrode 50b is disposed on the surface so as to cover the second base electrode layer 52b disposed on the surface so as to cover the stacked body 20, and the second base electrode layer 52b. A second conductive resin layer 54b, and a second plating layer 60b disposed on the surface of the second conductive resin layer 54b so as to cover the second conductive resin layer 54b.

(First base electrode layer 52a and second base electrode layer 52b)
The first base electrode layer 52a is disposed on the surface so as to cover the first end surface 26a of the stacked body 20, and is extended from there to the first main surface 22a, the second main surface 22b, the first The first side surface 24a and the second side surface 24b are disposed so as to reach a part of each. The first base electrode layer 52a may be disposed only on the first end surface 26a of the stacked body 20. On the other hand, the second base electrode layer 52b is disposed on the surface so as to cover the second end surface 26b of the multilayer body 20, and is extended from there to the first main surface 22a and the second main surface 22b. The first side surface 24a and the second side surface 24b are partly arranged. The second base electrode layer 52b may be disposed only on the second end surface 26b of the stacked body 20. The thickness of the thickest portion of each of the first base electrode layer 52a and the second base electrode layer 52b is preferably 10 μm or more and 150 μm or less.

  Note that each of the first base electrode layer 52a and the second base electrode layer 52b may have a plurality of layers. Each of the first base electrode layer 52a and the second base electrode layer 52b is disposed by applying and baking a conductive paste containing metal and glass on the surface of the laminate 20, The internal electrode layer 40a and the second internal electrode layer 40b may be fired at the same time, or the first internal electrode layer 40a and the second internal electrode layer 40b may be fired and then applied and baked. May be arranged.

  Each of the first base electrode layer 52a and the second base electrode layer 52b includes metal and glass. The metal includes, for example, at least one selected from Cu, Ni, Ag, Pd, an Ag—Pd alloy, Au, and the like. Moreover, the said glass contains at least 1 sort (s) chosen from Si, Zn, Pd, Li, Na, K etc., for example.

(First conductive resin layer 54a and second conductive resin layer 54b)
The first conductive resin layer 54a is disposed on the surface so as to cover the first base electrode layer 52a disposed on the first end surface 26a of the stacked body 20, and is extended from there to the first The main surface 22a, the second main surface 22b, the first side surface 24a and the second side surface 24b are provided on the surface so as to cover up to the first base electrode layer 52a. Note that the first conductive resin layer 54a may be disposed on the surface of the first conductive electrode layer 54a so as to cover the first base electrode layer 52a disposed only on the first end surface 26a of the stacked body 20. On the other hand, the second conductive resin layer 54b is disposed on the surface so as to cover the second base electrode layer 52b disposed on the second end surface 26b of the stacked body 20, and is extended therefrom. The first main surface 22a, the second main surface 22b, the first side surface 24a, and the second side electrode 24b are disposed on the surface so as to cover the second base electrode layer 52b disposed on each. The second conductive resin layer 54b may be disposed on the surface so as to cover the second base electrode layer 52b disposed only on the second end surface 26b of the stacked body 20. The thickness of each of the first conductive resin layer 54a and the second conductive resin layer 54b is preferably about 20 μm to 150 μm.

  Each of the first conductive resin layer 54a and the second conductive resin layer 54b includes a thermosetting resin and a metal component.

  The thermosetting resin contained in each of the first conductive resin layer 54a and the second conductive resin layer 54b is preferably an epoxy resin excellent in heat resistance, moisture resistance, adhesion, and the like. In addition, various well-known things, such as a phenol resin, a urethane resin, a silicone resin, a polyimide resin, can be used for a thermosetting resin. Each of the first conductive resin layer 54a and the second conductive resin layer 54b preferably includes a curing agent together with the thermosetting resin. As the curing agent, when the base thermosetting resin is an epoxy resin, various known compounds such as phenol, amine, acid anhydride, and imidazole can be used.

  Each of the first conductive resin layer 54a and the second conductive resin layer 54b includes a thermosetting resin, so that, for example, the first conductive resin layer 54a and the second conductive resin layer 54b are more flexible than a base electrode layer made of a fired product of a plating film or a conductive paste. Rich. Therefore, each of the first conductive resin layer 54a and the second conductive resin layer 54b functions as a buffer layer when a physical impact or an impact caused by a thermal cycle is applied to the multilayer ceramic capacitor 10, and a crack is generated. Can be prevented.

  The metal component contained in each of the first conductive resin layer 54a and the second conductive resin layer 54b may be spherical or flat metal powder (conductive filler), but the shape is not particularly limited. . The average particle diameter of the metal component may be, for example, about 0.3 μm or more and 10 μm or less.

  The metal component contained in each of the first conductive resin layer 54a and the second conductive resin layer 54b may be a metal powder composed of only one type of metal component, or a metal composed of a plurality of types of metal components. Powder may be used. In particular, when the first base electrode layer 52a and the second base electrode layer 52b are disposed on the surface of the laminate 20 as in this embodiment, use metal powder made of only one type of metal component. Is preferred. On the other hand, when the first base electrode layer 52a and the second base electrode layer 52b are not disposed on the surface of the stacked body 20, that is, the first conductive resin layer 54a and the second conductive resin layer 54b are respectively When directly disposed on the surface of the laminate 20, it is preferable to use a metal powder composed of a first metal component and a second metal component (that is, two types of metal components).

  When metal powder composed of only one type of metal component is used in each of the first conductive resin layer 54a and the second conductive resin layer 54b, the metal component may be a base metal coated with Cu, Ag, or Ag. Powder can be used. Among these, it is preferable to use Ag. This is because Ag is suitable for an electrode material because it has the lowest specific resistance among metals, and is a noble metal and therefore has high resistance without being oxidized. On the other hand, by using the base metal powder coated with Ag, it is possible to make the metal powder of the base material inexpensive while maintaining the characteristics of Ag.

  In each of the first conductive resin layer 54a and the second conductive resin layer 54b, metal powder composed of a first metal component and a second metal component (that is, two types of metal components) is used (particularly, When the first base electrode layer 52a and the second base electrode layer 52b are not disposed on the surface of the stacked body 20, that is, the first conductive resin layer 54a and the second conductive resin layer 54b are respectively stacked. For example, the following first metal component and second metal component can be used.

  The first metal component is preferably made of, for example, Sn, In, Bi, or an alloy containing at least one of these metals. Especially, it is preferable that a 1st metal component consists of an alloy containing Sn or Sn. Specific examples of the alloy containing Sn include, for example, Sn—Ag, Sn—Bi, Sn—Ag—Cu, and the like. The first metal component may be spherical or flat metal powder (conductive filler), but the shape is not particularly limited. The first metal component softens and flows at a relatively low temperature during the heat treatment, and forms a compound with the metal constituting the first internal electrode layer 40a and the second internal electrode layer 40b.

  The content of the first metal component relative to the total weight of the first metal component, the second metal component, and the thermosetting resin in each of the first external electrode 50a and the second external electrode 50b after curing is 20%. % To 40% by weight, more preferably 22.0% to 37.2% by weight. When the content of the first metal component is too small, there is a possibility that the bonding strength between the laminate 20 and each of the first conductive resin layer 54a and the second conductive resin layer 54b cannot be sufficiently ensured. . On the other hand, when the content of the first metal component is too large, the first metal component remaining in each of the first conductive resin layer 54a and the second conductive resin layer 54b, that is, the second metal component and The unreacted first metal component can be increased. Thereby, for example, the first conductive resin layer 54a and the second conductive resin layer 54b may be deformed by heat applied during reflow.

  The second metal component is preferably made of a metal such as Cu, Ag, Pd, Pt, or Au, or an alloy containing at least one of these metals. Especially, it is preferable that a 2nd metal component is Cu or Ag. The second metal component may be spherical or flat metal powder (conductive filler), but its shape is not particularly limited. The second metal component mainly has electrical conductivity in each of the first conductive resin layer 54a and the second conductive resin layer 54b. Specifically, a current path is formed in each of the first external electrode 50a and the second external electrode 50b by the contact between the second metal components or the contact between the first metal component and the second metal component. .

  The content of the second metal component relative to the total weight of the first metal component, the second metal component, and the thermosetting resin in each of the first external electrode 50a and the second external electrode 50b after curing is 30%. % To 70% by weight, more preferably 41.2% to 64% by weight. If the content of the second metal component is too small, the conductivity of the first external electrode 50a and the second external electrode 50b may be reduced, and the equivalent series resistance (ESR) of the multilayer ceramic capacitor 10 may be increased. . On the other hand, when the content of the second metal component is too large, the content of the thermosetting resin is decreased, so that the stress relaxation effect of the first external electrode 50a and the second external electrode 50b becomes too low. There is a fear.

  Comparing the melting points of the first metal component and the second metal component, the first metal component is relatively lower than the second metal component. Specifically, the melting point of the first metal component is preferably 550 ° C. or lower, and more preferably 180 ° C. or higher and 340 ° C. or lower. On the other hand, the melting point of the second metal component is preferably 850 ° C. or higher and 1050 ° C. or lower.

  The thermosetting resin has a content after curing with respect to the total weight of the first metal component, the second metal component, and the thermosetting resin in each of the first external electrode 50a and the second external electrode 50b. It is preferably from 40% by weight to 40% by weight, and more preferably from 9.8% by weight to 31.5% by weight. If the content of the thermosetting resin is too small, the stress relaxation effect of the first external electrode 50a and the second external electrode 50b is too low, and there is a possibility that the external impact cannot be absorbed sufficiently. On the other hand, when the content of the thermosetting resin is too large, the electrical conductivity of the first external electrode 50a and the second external electrode 50b may decrease, and the equivalent series resistance of the multilayer ceramic capacitor 10 may increase.

  The concentration of the metal component exposed on the surface of each of the first conductive resin layer 54a and the second conductive resin layer 54b is preferably 7% or more. Here, the concentration of the metal component exposed on the surface is the ratio of the number of atoms of the metal component exposed from the surface to the total number of atoms of the conductive resin layer when viewed in cross section. In addition, the said metal component density | concentration was measured as follows. First, the surface of the center part of the end surface of each of the first conductive resin layer 54a and the second conductive resin layer 54b was irradiated with monochromatic AlKα rays having a spot diameter of 100 μm, and a photoelectron spectrum was obtained. Next, the peak surface of each photoelectron peak of the element contained in the conductive resin layer was determined from the obtained photoelectron spectrum. Lastly, sensitivity correction was performed by multiplying the peak area of each element by the relative sensitivity coefficient, and (metal component peak area) / (total peak area) × 100 [atom%] was calculated to obtain the metal component concentration. The metal component concentration and the surface roughness Ra exposed on the surface of each of the first conductive resin layer 54a and the second conductive resin layer 54b are the first conductive resin layer 54a and the second conductive resin layer 54b. This can be realized by performing an oxygen plasma treatment after disposing. By performing the oxygen plasma treatment, only the resin portions on the surfaces of the first conductive resin layer 54a and the second conductive resin layer 54b can be chemically removed. Thereby, it is possible to increase the concentration of the metal component exposed on the surface of each of the first conductive resin layer 54a and the second conductive resin layer 54b. The oxygen plasma treatment will be described in detail in a method for manufacturing a multilayer ceramic capacitor described later. The metal component concentration can be adjusted by appropriately changing the oscillation frequency, the applied voltage between the electrodes, the processing time, the degree of vacuum, and the like during the oxygen plasma processing.

(First plating layer 60a and second plating layer 60b)
The first plating layer 60a is disposed on the surface so as to cover the first conductive resin layer 54a disposed on the first end surface 26a of the stacked body 20, and is extended from there to form the first plating layer 60a. The main surface 22a, the second main surface 22b, the first side surface 24a, and the second side surface 24b are disposed on the surfaces so as to cover up to the first conductive resin layer 54a disposed on each. The first plating layer 60a may be disposed on the surface so as to cover the first conductive resin layer 54a disposed only on the first end surface 26a of the stacked body 20. On the other hand, the second plating layer 60b is disposed on the surface so as to cover the second conductive resin layer 54b disposed on the second end surface 26b of the stacked body 20, and is extended from there. The first main surface 22a, the second main surface 22b, the first side surface 24a, and the second side surface 24b are disposed on the surface so as to cover up to the second conductive resin layer 54b. . The second plating layer 60b may be disposed on the surface of the second plating layer 60b so as to cover the second conductive resin layer 54b disposed only on the second end surface 26b of the stacked body 20.

  Each of the first plating layer 60a and the second plating layer 60b includes, for example, at least one selected from Cu, Ni, Sn, Ag, Pd, an Ag—Pd alloy, Au, and the like. Each of the first plating layer 60a and the second plating layer 60b may have a single-layer structure or a multi-layer structure, but a two-layer structure including the Ni plating layer 62 and the Sn plating layer 64 It is preferable that

  The Ni plating layer 62 of the first plating layer 60a is disposed on the surface so as to cover the first conductive resin layer 54a. On the other hand, the Ni plating layer 62 of the second plating layer 60b is disposed on the surface so as to cover the second conductive resin layer 54b. The thickness of the Ni plating layer 62 is preferably 1 μm or more and 15 μm or less. By disposing the Ni plating layer 62 as described above, when the multilayer ceramic capacitor 10 is mounted, the first base electrode layer 52a, the second base electrode layer 52b, the first conductive resin layer 54a, and the second It is possible to prevent the second conductive resin layer 54b from being eroded by the mounting solder.

  The Sn plating layer 64 of the first plating layer 60a is disposed on the surface so as to cover the Ni plating layer 62 of the first plating layer 60a. On the other hand, the Sn plating layer 64 of the second plating layer 60b is disposed on the surface so as to cover the Ni plating layer 62 of the second plating layer 60b. The thickness of the Sn plating layer 64 is preferably 1 μm or more and 15 μm or less. By disposing the Sn plating layer 64 as described above, since the wettability of the mounting solder is improved when the multilayer ceramic capacitor 10 is mounted, the mounting can be easily performed.

(effect)
In the multilayer ceramic capacitor 10 according to this embodiment, the concentration of the metal component exposed on the surface of each of the first conductive resin layer 54a and the second conductive resin layer 54b is increased by oxygen plasma treatment, and is 7% or more. It is. Therefore, it is possible to sufficiently ensure the metal component that is the starting point of the plating growth, and the solder wet-up is good during mounting. Moreover, since it becomes easy to conduct | electrically_connect at the time of plating layer formation, mountability improves. Thereby, non-wetting of the solder that may occur at the time of mounting is suppressed, so that the first plating layer 60a and the second plating layer 60b having a smooth and sufficient thickness can be provided. And since the 1st plating layer 60a and the 2nd plating layer 60b are smooth and have sufficient thickness, a sealing performance improves and a moisture penetration prevention function is fully acquired. As a result, in the multilayer ceramic capacitor 10 according to this embodiment, the solder explosion and non-wetting that may occur during mounting due to the thermosetting resin contained in the first external electrode 50a and the second external electrode 50b. Can be suppressed.

  The multilayer ceramic capacitor 10 according to this embodiment includes the first base electrode layer 52a and the second base electrode layer 52b, thereby forming the first conductive resin layer 54a and the second conductive resin layer 54b. Since the first metal component contained and the metal contained in the first internal electrode layer 40a and the second internal electrode layer 40b are alloyed, the bonding strength can be increased.

2. Manufacturing Method for Multilayer Ceramic Capacitor A manufacturing method for a multilayer ceramic electronic component according to the present invention will be described by taking the multilayer ceramic capacitor 10 according to the above-described embodiment as an example.

(Production of laminate)
First, a laminate having a structure in which a first internal electrode layer, a second internal electrode layer, and a ceramic layer are laminated is prepared. Specifically, it is as follows.

  First, a ceramic paste containing ceramic powder is applied in a sheet form by, for example, a screen printing method and dried to produce a ceramic green sheet.

  Next, a conductive paste for forming an internal electrode layer is applied to the surface of the ceramic green sheet in a predetermined pattern by, for example, a screen printing method to produce a ceramic green sheet on which a conductive pattern for forming the internal electrode layer is formed. Is done. In addition, a ceramic green sheet in which a conductive pattern for forming the internal electrode layer is not formed is produced. The ceramic paste and the conductive paste for forming the internal electrode layer may include, for example, a known binder or solvent.

  Then, after a predetermined number of ceramic green sheets not formed with internal electrode layer forming conductive patterns are laminated, ceramic green sheets with internal electrode layer forming conductive patterns formed thereon are sequentially laminated. A predetermined number of ceramic green sheets on which no conductive pattern for forming an internal electrode layer is formed are laminated on the surface. In this way, a mother laminate is produced.

  Furthermore, the mother laminate may be pressed in the T direction by means such as an isostatic press as required.

  Next, a plurality of raw laminates are produced by cutting the mother laminate into a predetermined shape and dimensions. The corners and ridges of the raw laminate may be rounded by applying barrel polishing or the like.

  And a raw laminated body is baked. The firing temperature of the raw laminate can be appropriately set according to the ceramic material or the conductive material, and can be, for example, about 900 ° C. to 1300 ° C.

  According to the above procedure, the opposing portions of the first internal electrode layer and the second internal electrode layer extend inside, and the extraction portions of the first internal electrode layer and the second internal electrode layer are drawn out to the end surfaces. A laminated body is produced. Thus, the process of preparing a laminated body is implemented.

(Formation of a pair of external electrodes)
Furthermore, a conductive paste is applied and baked on each of both end faces of the fired laminate to form a base electrode layer for each of the first external electrode and the second external electrode. The baking temperature at this time is preferably 700 ° C. or higher and 900 ° C. or lower.

Next, a conductive resin paste containing a thermosetting resin and a metal component (conductive filler) is applied so as to cover the base electrode layer, and heat treatment is performed at a temperature of 100 ° C. to 500 ° C. to thermally cure the resin. Thus, a conductive resin layer is formed. In this way, the step of forming the conductive resin layer is performed. Note that the atmosphere during the heat treatment is preferably an N ₂ atmosphere. The oxygen concentration is preferably suppressed to 100 ppm or less in order to prevent scattering of the resin and oxidation of the metal component.

  Then, after the step of forming the conductive resin layer is performed, oxygen plasma treatment is performed on the conductive resin layer.

  Details of the oxygen plasma treatment performed when the multilayer ceramic capacitor is manufactured will be described with reference to FIGS. FIG. 3 is a schematic diagram immediately before the oxygen plasma treatment is performed in manufacturing the multilayer ceramic capacitor according to the embodiment of the present invention. FIG. 4 is a schematic view immediately after the oxygen plasma treatment is performed when manufacturing the multilayer ceramic capacitor according to the embodiment of the present invention. 3 and 4, the surface of the portion exposed on the surface of the conductive resin layer of the metal component is clearly indicated by a thick line. Further, in FIG. 4, a portion that has already been removed and does not exist on the surface of the conductive resin layer is indicated by a broken line.

In the step of performing the oxygen plasma treatment, the resin on the surface of the conductive resin layer is removed, and the metal component contained in the conductive resin layer is exposed on the surface. The oxygen plasma treatment is performed by a plasma etching method with electrodes arranged above and below the object to be treated. The object to be processed is uniformly arranged on a mesh-like flat plate jig. At this time, the objects to be processed are preferably arranged so as not to overlap each other. In addition, the mesh-shaped flat plate jig can be uniformly processed on the front and back surfaces by providing a gap between the mesh plate and the lower electrode. Then, an active oxygen radical is generated by applying a high-frequency electromagnetic field between the upper and lower electrodes while maintaining a vacuum state while flowing oxygen gas. Active oxygen radicals are attached to the surface of the conductive resin layer. Then, volatile products (CO ₂ ) are generated by the active oxygen radicals and the resin portion of the conductive resin layer, and only the resin portion on the surface of the conductive resin layer is chemically removed. In this way, the concentration of the metal component exposed on the surface of the conductive resin layer can be increased. In this way, the step of performing the oxygen plasma treatment is performed.

  In the oxygen plasma treatment, the concentration of the metal component exposed on the surface of the conductive resin layer can be adjusted by appropriately changing the oscillation frequency, the applied voltage between the electrodes, the treatment time, and the degree of vacuum during the plasma treatment. The predetermined metal component concentration (7% or more) is a microwave having an oscillation frequency of 13.56 MHz or 2.45 GHz, an interelectrode applied voltage of 100 W to 3000 W, a processing time of 30 seconds to 120 seconds, and a vacuum degree of 10 Pa to 100 Pa. This can be achieved by appropriately changing within the following range. The atmospheric pressure is preferably 40 Pa or less. Further, nitrogen gas may be mixed in order to increase the plasma density.

  Finally, a Ni plating layer is formed on the surface of the conductive resin layer. As a method for forming the Ni plating layer, an electrolytic plating method can be used. If necessary, an upper plating layer such as a Sn plating layer can be formed on the surface of the Ni plating layer.

  As described above, the multilayer ceramic capacitor 10 according to one embodiment of the present invention can be manufactured.

(effect)
The manufacturing method of the multilayer ceramic capacitor according to this embodiment includes a metal component that chemically removes only the resin portion on the surface of the conductive resin layer and exposes it on the surface of the conductive resin layer by the step of performing oxygen plasma treatment. The concentration can be increased. As a result, a sufficient metal component can be secured on the surface of the conductive resin layer as a starting point for plating growth, and it becomes easy to conduct during the formation of the plating layer, so that a plating layer having a smooth and sufficient thickness can be easily formed. It becomes possible. In addition, the solder wet-up is good during mounting, and solder non-wetting can be suppressed, so that mountability is improved. And since a plating layer is smooth and has sufficient thickness, a sealing performance improves and a moisture penetration prevention function is fully acquired. Furthermore, the surface roughness of the conductive resin layer can be suppressed within a predetermined range by the step of performing the oxygen plasma treatment. As a result, the interface area between the conductive resin layer and the plating layer is increased, and the bonding strength between the multilayer ceramic capacitor and the mounting substrate can be improved. Since it is as above-mentioned, by using the manufacturing method which concerns on this invention, the explosion and the non-wetting of the solder which can occur at the time of mounting resulting from the thermosetting resin being contained in the external electrode are suppressed. Can be manufactured.
3. Experimental Example Hereinafter, an experimental example performed by the inventors to confirm the effect of the present invention will be described. In the experimental example, the samples (multilayer ceramic capacitors) of Examples 1 to 11 and Comparative Examples 1 and 2 having different concentrations of metal components exposed on the surface of the conductive resin layer were produced, respectively, and solder explosion occurred during mounting. The number of samples and the number of non-wetting samples were evaluated.

(Examples 1-11 and Comparative Examples 1 and 2)
According to the manufacturing method described above, about 1000 samples of each of Examples 1 to 11 and Comparative Examples 1 and 2 (multilayer ceramic capacitors) were manufactured. The specifications common to each sample are as follows.
-Overall dimensions including a pair of external electrodes (L dimension x W dimension x T dimension): 1.6 mm x 0.8 mm x 0.8 mm
・ Ceramic material: BaTiO ₃
・ Capacitance: 0.1μF
・ Rated voltage: 50V
Structure of external electrode Underlying electrode layer Electrode containing conductive metal (Cu) and glass Thickness: center part 40 μm, edge part 5 μm
Conductive resin layer Metal component: Ag
Thermosetting resin: Epoxy system Thermosetting temperature: 230 ° C
Thickness: 45 μm at the center and 3 μm at the edge
Plating layer Ni-plating layer (see Table 1 for thickness) and Sn-plating layer (thickness 4 μm) 2 layer structure (thickness is designed value)

  The metal component concentrations exposed on the surfaces of the conductive resin layers of Examples 1 to 11 and Comparative Examples 1 and 2 and the measured values of the Ni plating layer are as shown in Table 1 described later.

(Measuring method of metal component concentration exposed on the surface of the conductive resin layer)
The concentration of the metal component exposed on the surface of the conductive resin layer was measured using X-ray photoelectron spectroscopy. Specifically, first, the surface of the central portion of the end face of the conductive resin layer was irradiated with monochromatic AlKα rays having a spot diameter of 100 μm, and a photoelectron spectrum was obtained. Next, the peak surface of each photoelectron peak of the element contained in the conductive resin layer was determined from the obtained photoelectron spectrum. Lastly, sensitivity correction was performed by multiplying the peak area of each element by the relative sensitivity coefficient, and (metal component peak area) / (total peak area) × 100 [atom%] was calculated to obtain the metal component concentration.

(Ni plating layer thickness measurement method)
The method for measuring the thickness of the Ni plating layer is as follows. First, each sample (multilayer ceramic capacitor) was immersed in Enstrip TL105 (made by Meltex) for 45 seconds or more and 60 seconds or less. Next, the Sn plating layer disposed on the upper layer of the Ni plating layer was peeled off. Furthermore, it measured using the fluorescent X-ray micro part film thickness meter (SFT-9400, product made from SII nanotechnology) about the center part of the end surface of Ni plating layer. Finally, it was calculated by a calibration curve method. In addition, the result of the thickness measurement of the Ni plating layer shown in Table 1 is an average value of values measured at a plurality of locations on one end face side of the multilayer ceramic capacitor.

(Measurement method of solder explosion)
The method for measuring the solder explosion is as follows. First, about 1000 samples (multilayer ceramic capacitors) were each mounted on a mounting board printed with lead-free solder, and reflow mounted at a temperature of 280 ° C. or higher. And the board | substrate which carried out the reflow mounting was observed using the stereomicroscope (50 times visual field), and the sample in which the solder ball which scattered radially was confirmed was counted as a defect.

(Experimental result)
The results of the experimental example are shown in Table 1.

  As shown in Table 1, the number of samples in which solder explosion occurred and the number of samples in which solder non-wetting had occurred during the mounting of Examples 1 to 11 (metal component concentration of 7% or more) were Comparative Examples 1 and 2 (metal In comparison with those having a component concentration of less than 7%, both were less. In particular, the number of non-wetting samples of the solders of Examples 1 to 11 was zero. From this experimental result, by setting the concentration of the metal component exposed on the surface of the conductive resin layer to 7% or more, solder explosion and non-wetting that may occur during mounting due to the inclusion of the thermosetting resin in the external electrode Was able to be confirmed.

  In the above-described embodiments and experimental examples, the case where the first external electrode 50a includes the first base electrode layer 52a and the second external electrode 50b includes the second base electrode layer 52b has been described. However, it is not limited to this. That is, the first external electrode 50a may not include the first base electrode layer 52a, and the second external electrode 50b may not include the second base electrode layer 52b. In this case, each of the first conductive resin layer 54 a and the second conductive resin layer 54 b may be directly disposed on the surface of the stacked body 20. That is, the first conductive resin layer 54a is disposed on the surface so as to cover the first end surface 26a of the laminate 20, and is extended from there to the first main surface 22a and the second main surface. 22b, the first side surface 24a, and the second side surface 24b may be disposed so as to reach a part thereof. Note that the first conductive resin layer 54 a may be disposed only on the first end surface 26 a of the stacked body 20. On the other hand, the second conductive resin layer 54b is disposed on the surface so as to cover the second end surface 26b of the stacked body 20, and is extended from there to the first main surface 22a and the second main surface. 22b, the first side surface 24a, and the second side surface 24b may be disposed so as to reach a part thereof. Note that the second conductive resin 54 b may be disposed only on the second end surface 26 b of the stacked body 20.

  In the above-described embodiments and experimental examples, the multilayer ceramic capacitor has been described as an example of the multilayer ceramic electronic component according to the present invention, but the present invention is not limited to this. That is, the multilayer ceramic electronic component according to the present invention may be a piezoelectric component, a thermistor, or an inductor. When the multilayer ceramic electronic component is a piezoelectric component, a piezoelectric ceramic can be used as the ceramic material. Specific examples of the piezoelectric ceramic include, for example, PZT (lead zirconate titanate) ceramic. When the multilayer ceramic electronic component is a thermistor, a semiconductor ceramic can be used as the ceramic material. Specific examples of semiconductor ceramics include spinel ceramics. Furthermore, when the multilayer ceramic electronic component is an inductor, a magnetic ceramic can be used as the ceramic material. Specific examples of the magnetic ceramic include a ferrite ceramic.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is carried out within the range of the summary.

DESCRIPTION OF SYMBOLS 10 Multilayer ceramic capacitor 20 Laminated body 22a 1st main surface 22b 2nd main surface 24a 1st side surface 24b 2nd side surface 26a 1st end surface 26b 2nd end surface 30 Ceramic layer 40a 1st internal electrode layer 40b Second internal electrode layer 50a First external electrode 50b Second external electrode 52a First base electrode layer 52b Second base electrode layer 54a First conductive resin layer 54b Second conductive resin layer 56 Metal Component 60a First plating layer 60b Second plating layer 62 Ni plating layer 64 Sn plating layer

Claims (3)

A plurality of ceramic layers and a plurality of internal electrode layers are alternately stacked to form a rectangular parallelepiped shape, a pair of main surfaces facing each other in the stacking direction and a pair of facing each other in the width direction orthogonal to the stacking direction A laminate including a side surface and a pair of end faces facing each other in a length direction orthogonal to the lamination direction and the width direction;
A multilayer ceramic electronic component comprising a pair of external electrodes electrically connected to the plurality of internal electrode layers by being formed on a surface of the multilayer body,
Each of the pair of external electrodes includes a conductive resin layer containing a thermosetting resin and a metal component, and a plating layer disposed on the surface of the conductive resin layer,
The multilayer ceramic electronic component, wherein the concentration of the metal component exposed on the surface of the conductive resin layer is 7% or more.   2. The multilayer ceramic electronic component according to claim 1, wherein each of the pair of external electrodes further includes a base electrode layer that is disposed between the multilayer body and the conductive resin layer and includes a metal and glass. A plurality of ceramic layers and a plurality of internal electrode layers are alternately stacked to form a rectangular parallelepiped shape, a pair of main surfaces facing each other in the stacking direction and a pair of facing each other in the width direction orthogonal to the stacking direction A laminate including a side surface and a pair of end surfaces facing each other in the length direction orthogonal to the stacking direction and the width direction, and electrically formed on the plurality of internal electrode layers by being formed on a surface of the stack. A method for producing a multilayer ceramic electronic component comprising a pair of external electrodes to be connected,
Preparing a laminate in which the plurality of ceramic layers and the plurality of internal electrode layers are alternately laminated;
Forming a conductive resin layer by applying and curing a paste containing the thermosetting resin and the metal component on the surface of the laminate; and
And a step of performing oxygen plasma treatment on the conductive resin layer,
In the step of performing the oxygen plasma treatment, a resin on the surface of the conductive resin layer is removed, and the metal component is exposed on the surface of the conductive resin layer.