Multilayer ceramic capacitor and multilayer ceramic capacitor production method

Abstract

Provided is a multilayer ceramic electronic component with which it is possible to suppress a decrease in reliability. A multilayer ceramic capacitor 10 comprises: a laminate body 12 including a plurality of ceramic layers 14 and a plurality of internal electrode layers 16; and an external electrode 30 connected to the plurality of internal electrode layers 16 at a portion of the laminate body 12 where the plurality of internal electrode layers 16 are exposed. The external electrode 30 includes a base electrode layer 32 in contact with the laminate body 12. The base electrode layer 32 includes a conductive metal and glass 40 containing Si and Ba. The surface of the glass 40 exposed from the base electrode layer 32 includes an insoluble film 42 that contains a compound in which Ba and P are bonded, and a compound in which Ba and S are bonded.

Description

Multilayer Ceramic Capacitor and Method for Manufacturing the Same

[0001] The present invention relates to a multilayer ceramic capacitor and a method for manufacturing the same.

[0002] A large demand is expected for multilayer ceramic capacitors (MLCC: MultiLayer Ceramic Capacitor) as electronic components mounted in automobiles, electronic components of mobile phones, and the like. A multilayer ceramic capacitor includes a laminate having internal electrode layers and ceramic layers, and external electrodes.

[0003] Such a general multilayer ceramic capacitor includes a laminate in which a plurality of ceramic layers and a plurality of internal electrode layers are laminated, and external electrodes are formed on the outer surface of the laminate. The internal electrode layers are drawn out to the end faces and side faces of the laminate and are connected to the external electrodes. The external electrodes are composed of, for example, a base electrode layer formed by applying a conductive paste to the laminate and firing it, and a plating layer formed on the outer surface of the base electrode layer. The plating layer may be composed of a plurality of layers as necessary.

[0004] For example, Patent Document 1 discloses a conductive paste for a base electrode that can prevent the intrusion of a plating solution and can form an external electrode (including a base electrode layer) having excellent connectivity with the internal electrode layer. The conductive paste for the base electrode of Patent Document 1 contains metal powder, and the particle size of this metal powder is adjusted. Thereby, the packing density of the metal powder is improved to form a dense sintered body. Therefore, the intrusion of the plating solution can be suppressed, and the reliability of the multilayer ceramic capacitor is improved. Also, by limiting the amount of glass powder in the conductive paste to a predetermined range, the intrusion of the plating solution is suppressed and the reliability of the multilayer ceramic capacitor is improved.

[0005] JP-A-2007-294633

[0006] As described above, Patent Document 1 improves the reliability of multilayer ceramic capacitors by adjusting the particle size of metal powder and the amount of glass powder in the conductive paste. However, there is also a need to improve the reliability of multilayer ceramic capacitors with a configuration different from that of Patent Document 1. Herein, the present inventors have newly discovered a configuration that suppresses the penetration of plating solution and improves the reliability of multilayer ceramic capacitors with a configuration different from that of Patent Document 1.

[0007] Therefore, the primary objective of this invention is to provide a multilayer ceramic capacitor and a method for manufacturing a multilayer ceramic capacitor that can improve reliability.

[0008] The multilayer ceramic capacitor according to this invention comprises a laminate including a plurality of ceramic layers and a plurality of internal electrode layers, and an external electrode connected to the plurality of internal electrode layers in the portion where the plurality of internal electrode layers are exposed in the laminate, wherein the external electrode includes a base electrode layer in contact with the laminate, the base electrode layer includes a conductive metal and glass having Si and Ba, and the surface of the glass exposed from the base electrode layer includes an insolubilization film having a compound to which Ba and P are bonded and a compound to which Ba and S are bonded.

[0009] According to the multilayer ceramic capacitor of this invention, an insolubilizing film having a compound in which Ba and P are bonded and a compound in which Ba and S are bonded on the surface of the glass exposed from the underlying electrode layer suppresses the dissolution of the glass in the plating solution. Therefore, the insolubilizing film functions as a barrier film against the plating solution. As a result, the glass is prevented from being eroded by the plating solution and the plating solution is prevented from penetrating into the interior of the multilayer ceramic capacitor. Thus, the reliability of the multilayer ceramic capacitor can be improved.

[0010] A method for manufacturing a multilayer ceramic capacitor according to this invention comprises the steps of: preparing a laminate including a plurality of ceramic layers and a plurality of internal electrode layers; forming a Cu plating layer on the laminate using a pyrophosphate-based Cu plating solution; and forming an external electrode in which the Cu plating layer, the base electrode layer and the plating layer are laminated by forming a base electrode layer and a plating layer on the Cu plating layer, wherein the pyrophosphate-based Cu plating solution contains a complex of sulfate ions, Cu ions and pyrophosphate ions, and in the step of forming the Cu plating layer on the laminate, an insolubilization film is formed on the surface of the glass.

[0011] In a multilayer ceramic capacitor formed by the manufacturing method according to this invention, an insolubilizing film is formed on the surface of the glass exposed from the underlying electrode layer, having a compound to which Ba and P are bonded, and a compound to which Ba and S are bonded, thereby suppressing the dissolution of the glass in the plating solution. Therefore, the insolubilizing film functions as a barrier film against the plating solution. As a result, the glass is prevented from being eroded by the plating solution, and the penetration of the plating solution into the interior of the multilayer ceramic capacitor is suppressed. Thus, the reliability of the multilayer ceramic capacitor can be improved.

[0012] This invention provides a multilayer ceramic capacitor and a method for manufacturing a multilayer ceramic capacitor that can improve reliability.

[0013] The above-mentioned objectives, other objectives, features, and advantages of this invention will become even clearer from the following description of embodiments for carrying out the invention, with reference to the drawings.

[0014] This is an external perspective view showing an example of a multilayer ceramic capacitor according to the first embodiment of this invention. This is a cross-sectional view along line II-II in Figure 1. This is a cross-sectional view along line III-III in Figure 1. This is an enlarged cross-sectional view of part A of the first external electrode in the cross-sectional view shown in Figure 2. This is an external perspective view showing an example of a multilayer ceramic capacitor according to the second embodiment of this invention. This is a cross-sectional view along line II-II in Figure 5. This is an enlarged cross-sectional view of part B of the first external electrode in the cross-sectional view shown in Figure 6.

[0015] <First Embodiment> As an example of a multilayer ceramic electronic component according to an embodiment of this invention, a multilayer ceramic capacitor will be described. In this embodiment, the multilayer ceramic capacitor is a two-terminal type multilayer ceramic capacitor.

[0016] Figure 1 is an external perspective view showing an example of a multilayer ceramic capacitor according to the first embodiment of the present invention. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. Figure 3 is a cross-sectional view taken along line III-III in Figure 1. Figure 4 is an enlarged cross-sectional view of part A of the first external electrode in the cross-sectional view shown in Figure 2.

[0017] As shown in Figures 1 to 3, the multilayer ceramic capacitor 10 includes a rectangular parallelepiped laminate 12 and external electrodes 30 arranged at both ends of the laminate 12.

[0018] The laminate 12 has a first main surface 12a and a second main surface 12b facing each other in the height direction x (lamination direction), a first side surface 12c and a second side surface 12d facing each other in the width direction y perpendicular to the height direction x, and a first end surface 12e and a second end surface 12f facing each other in the length direction z perpendicular to the height direction x and the width direction y. The laminate 12 of this embodiment has rounded corners and edges. A corner is the part where three adjacent surfaces of the laminate 12 intersect, and an edge is the part where two adjacent surfaces of the laminate 12 intersect. In addition, some or all of the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, and the first end surface 12e and the second end surface 12f may have irregularities or other features formed on them.

[0019] The laminate 12 includes an outer layer 14a composed of multiple ceramic layers 14, and an inner layer 14b composed of one or more ceramic layers 14 and multiple internal electrode layers 16 arranged on them. The outer layer 14a is located on the side of the first main surface 12a and the side of the second main surface 12b of the laminate 12. The outer layer 14a is an aggregate of multiple ceramic layers 14 (first outer layer) located between the first main surface 12a and the internal electrode layer 16 closest to the first main surface 12a, and multiple ceramic layers 14 (second outer layer) located between the second main surface 12b and the internal electrode layer 16 closest to the second main surface 12b. The region sandwiched between the two outer layer sections 14a is the inner layer section 14b. In the inner layer section 14b, the ceramic layers 14 and internal electrode layers 16 are stacked alternately in the height direction x.

[0020] The portion of the laminate 12 sandwiched between the first outer layer and the second outer layer, where the first internal electrode layer 16a and the second internal electrode layer 16b (described later) face each other, is called the opposing portion (effective layer portion). The portion between the opposing portion and the first side surface 12c, and the portion between the opposing portion and the second side surface 12d, are also called the W gap or side gap. The portion between the opposing portion and the first end surface 12e, and the portion between the opposing portion and the second end surface 12f, which includes the lead-out electrode portion of either the first internal electrode layer 16a or the second internal electrode layer 16b, is also called the L gap or end gap.

[0021] The dimensions of the laminate 12 are not particularly limited, but it is preferable that the length z dimension is 0.39 mm or more and 3.30 mm or less, the height x dimension is 0.21 mm or more and 2.70 mm or less, and the width y dimension is 0.21 mm or more and 2.70 mm or less.

[0022] As the dielectric material for forming the ceramic layer 14, for example, a dielectric ceramic containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3 can be used. When the above dielectric material is included as the main component, depending on the desired properties of the laminate 12, a material with a lower content of minor components than the main component, such as Mn compounds, Fe compounds, Cr compounds, Co compounds, or Ni compounds, may be used.

[0023] The thickness of the ceramic layer 14 after firing is preferably 0.2 μm or more and 2 μm or less. The number of laminated ceramic layers 14 is preferably 15 or more and 1000 or less. More preferably, the thickness is preferably 0.2 μm or more and 0.55 μm or less. This makes it possible to increase the number of laminated layers, which can contribute to higher capacity. The number of ceramic layers 14 is the total number of ceramic layers 14 in the inner layer portion 14b and the number of ceramic layers 14 in the outer layer portion 14a on the first main surface 12a side and the outer layer portion 14a on the second main surface 12b side.

[0024] The laminate 12 has a plurality of internal electrode layers 16, consisting of a plurality of first internal electrode layers 16a drawn out from the first end face 12e and a plurality of second internal electrode layers 16b drawn out from the second end face 12f. The plurality of first internal electrode layers 16a and the plurality of second internal electrode layers 16b are embedded in the inner layer portion 14b so as to be alternately arranged at equal intervals along the height direction x of the laminate 12, with the ceramic layer 14 in between. The surfaces of the plurality of first internal electrode layers 16a and the plurality of second internal electrode layers 16b are generally parallel to the first main surface 12a and the second main surface 12b, and are, for example, roughly rectangular in plan view.

[0025] The first internal electrode layer 16a is arranged on a plurality of ceramic layers 14 and is located inside the laminate 12. The first internal electrode layer 16a has a first opposing electrode portion 26a facing the second internal electrode layer 16b, and a first drawn-out electrode portion 28a located on one end side of the first internal electrode layer 16a, extending from the first opposing electrode portion 26a to the first end face 12e of the laminate 12. The end of the first drawn-out electrode portion 28a is drawn out to the surface of the first end face 12e and exposed from the laminate 12. In other words, the first drawn-out electrode portion 28a is not exposed on the first main surface 12a, the second main surface 12b, the first side surface 12c, the second side surface 12d, and the second end face 12f. The end of the first opposing electrode portion 26a is positioned recessed in the width direction from the surface of the second end face 12f.

[0026] The shape of the first opposing electrode portion 26a of the first internal electrode layer 16a is not particularly limited, but is preferably rectangular in plan view. However, the corners may be rounded in plan view, or the corners may be formed at an angle in plan view (tapered). It may also be tapered in plan view with a slope towards one side.

[0027] The shape of the first lead-out electrode portion 28a of the first internal electrode layer 16a is not particularly limited, but is preferably rectangular in plan view. However, the corners may be rounded in plan view, or the corners may be formed at an angle in plan view (tapered). It may also be tapered in plan view with a slope towards one side.

[0028] The width of the first opposing electrode portion 26a of the first internal electrode layer 16a and the width of the first leading electrode portion 28a of the first internal electrode layer 16a may be the same, or one of them may be narrower.

[0029] The second internal electrode layer 16b is arranged on a plurality of ceramic layers 14 and is located inside the laminate 12. The second internal electrode layer 16b has a second opposing electrode portion 26b facing the first internal electrode layer 16a, and a second drawn-out electrode portion 28b located on one end side of the second internal electrode layer 16b, extending from the second opposing electrode portion 26b to the second end face 12f of the laminate 12. The end of the second drawn-out electrode portion 28b is drawn out to the surface of the second end face 12f and exposed from the laminate 12. In other words, the second drawn-out electrode portion 28b is not exposed on the first main surface 12a, the second main surface 12b, the first side surface 12c, the second side surface 12d, and the first end face 12e. The end of the second opposing electrode portion 26b is positioned recessed in the width direction from the surface of the first end face 12e.

[0030] The shape of the second opposing electrode portion 26b of the second internal electrode layer 16b is not particularly limited, but is preferably rectangular in plan view. However, the corners may be rounded in plan view, or the corners may be formed at an angle in plan view (tapered). It may also be tapered in plan view with a slope towards one side.

[0031] The shape of the second lead-out electrode portion 28b of the second internal electrode layer 16b is not particularly limited, but is preferably rectangular in plan view. However, the corners may be rounded in plan view, or the corners may be formed at an angle in plan view (tapered). It may also be tapered in plan view with a slope towards one side.

[0032] The width of the second opposing electrode portion 26b of the second internal electrode layer 16b and the width of the second leading electrode portion 28b of the second internal electrode layer 16b may be the same width, or one of them may be narrower.

[0033] The first internal electrode layer 16a and the second internal electrode layer 16b can be made of a suitable conductive material such as metals like Ni, Cu, Ag, Pd, and Au, or alloys containing at least one of these metals, such as Ag-Pd alloys. Furthermore, when the laminate 12 including the internal electrode layers 16 and the integrated object including the external electrodes 30 on the surface of the laminate 12 are fired simultaneously, the metal constituting the internal electrode layer 16 will form a compound with the metal contained in the external electrodes 30.

[0034] The thickness of each of the internal electrode layers 16, namely the first internal electrode layer 16a and the second internal electrode layer 16b, is preferably 0.2 μm or more and 2.0 μm or less. More preferably, it is 0.2 μm or more and 0.5 μm or less. In addition, the total number of the first internal electrode layer 16a and the second internal electrode layer 16b is preferably 15 or more and 1000 or less.

[0035] External electrodes 30 are arranged on the first end face 12e and the second end face 12f of the laminate 12, as shown in Figures 1 to 3.

[0036] The external electrode 30 has a first external electrode 30a and a second external electrode 30b.

[0037] The first external electrode 30a is connected to the first internal electrode layer 16a and is positioned on at least the surface of the first end face 12e. In this case, the first external electrode 30a is electrically connected to the first lead-out electrode portion 28a of the first internal electrode layer 16a. In this embodiment, the first external electrode 30a extends from the first end face 12e and is also positioned on a part of the first main surface 12a and a part of the second main surface 12b, as well as a part of the first side surface 12c and a part of the second side surface 12d.

[0038] The second external electrode 30b is connected to the second internal electrode layer 16b and is positioned on at least the surface of the second end face 12f. In this case, the second external electrode 30b is electrically connected to the second lead-out electrode portion 28b of the second internal electrode layer 16b. In this embodiment, the second external electrode 30b extends from the second end face 12f and is also positioned on a portion of the first main surface 12a and a portion of the second main surface 12b, as well as a portion of the first side surface 12c and a portion of the second side surface 12d.

[0039] Within the laminate 12, capacitance is formed when the first opposing electrode portion 26a of the first internal electrode layer 16a and the second opposing electrode portion 26b of the second internal electrode layer 16b face each other via the ceramic layer 14. As a result, capacitance can be obtained between the first external electrode 30a to which the first internal electrode layer 16a is connected and the second external electrode 30b to which the second internal electrode layer 16b is connected, and the characteristics of a capacitor are exhibited.

[0040] The external electrode 30 is preferably composed of a base electrode layer 32 and a plating layer 34. In this embodiment, the external electrode 30 includes a base electrode layer 32 and a plating layer 34 disposed on the base electrode layer 32. The plating layer 34 includes a first plating layer 34a and a second plating layer 34b. The first external electrode 30a has a first base electrode layer 32a, a first lower plating layer 34a1 disposed on the first base electrode layer 32a, and a first upper plating layer 34a2 disposed on the first lower plating layer 34a1. The second external electrode 30b has a second base electrode layer 32b, a second lower plating layer 34b1 disposed on the second base electrode layer 32b, and a second upper plating layer 34b2 disposed on the second lower plating layer 34b1.

[0041] The first base electrode layer 32a is connected to the first internal electrode layer 16a and is positioned on the surface of the first end face 12e. In this case, the first base electrode layer 32a is electrically connected to the first lead-out electrode portion 28a of the first internal electrode layer 16a. In this embodiment, the first base electrode layer 32a extends from the first end face 12e and is also positioned on a part of the first main surface 12a and a part of the second main surface 12b, as well as a part of the first side surface 12c and a part of the second side surface 12d.

[0042] The second base electrode layer 32b is connected to the second internal electrode layer 16b and is positioned on the surface of the second end face 12f. In this case, the second base electrode layer 32b is electrically connected to the second lead electrode portion 28b of the second internal electrode layer 16b. In this embodiment, the second base electrode layer 32b extends from the second end face 12f and is also positioned on a part of the first main surface 12a and a part of the second main surface 12b, as well as a part of the first side surface 12c and a part of the second side surface 12d.

[0043] The base electrode layer 32 contains a conductive metal and glass 40. As the conductive metal of the base electrode layer 32, for example, it contains at least one selected from Cu, Ni, Ag, Pb, an Ag-Pb alloy, Au, or the like. The conductive metal in the present embodiment is mainly Cu. Further, as the glass 40 of the base electrode layer 32, it mainly contains Si and Ba. Furthermore, as the glass 40 of the base electrode layer 32, preferably, it can contain at least one selected from Al, B, Pd, Mg, Li, or the like. The glass 40 in the present embodiment mainly contains the components of Si, Ba, and Al. Also, in the present embodiment, the glass 40 is configured such that the elution of the glass 40 is suppressed in the plating process for the base electrode layer 32. Specifically, as described later, the glass 40 contains an insolubilized film 42. And the insolubilized film 42 contains a compound in which Ba and P insoluble in the plating solution in the plating process are bonded, and a compound in which Ba and S are bonded. Therefore, in the present embodiment, the insolubilized film 42 contains Si, Ba, Al, and P as each component.

[0044] The base electrode layer 32 may be a plurality of layers. The base electrode layer 32 is formed by applying a conductive paste containing metal powder and glass powder to the laminate 12 and baking it, and it may be fired simultaneously with the ceramic layer 14 and the internal electrode layer 16, or it may be baked after firing the ceramic layer 14 and the internal electrode layer like, it can contain at least one selected from Al, B, Pd, Mg, Li, or the like. The glass 40 in the present embodiment mainly contains the components of Si, Ba, and Al. Also, in the present embodiment, the glass 40 is configured such that the elution of the glass 40 is suppressed in the plating process for the base electrode layer 32. Specifically, as described later, the glass 40 contains an insolubilized film 42. And the insolubilized film 42 contains a compound in which Ba and P insoluble in the plating solution in the plating process are bonded, and a compound in which Ba and S are bonded. Therefore, in the present embodiment, the insolubilized film 42 contains Si, Ba, Al, and P as each component.

[0045] The thicknesses of the first and second baked layers at the central portion in the height direction x of the first and second base electrode layers 32a and 32b located on the first end face and the second end face 12f are preferably, for example, about 3 μm or more and 20 μm or less. Further, when the base electrode layer 32 is provided on the first main face 12a and the second main face 12b, the first side face 12c and the second side face 12d, the thicknesses of the first and second baked layers at the central portion in the length direction z of the first and second base electrode layers 32a and at the first main face 12a and the second main face 12b, the first side face 12c and the second side face 12d are preferably, for example, about 1 μm or more and 20 μm or less.

[0046] Next, we will further explain the glass 40 contained in the base electrode layer 32. As shown in Figure 4, a portion of the glass 40 is exposed on the surface of the base electrode layer 32. On the other hand, there is also glass located on the laminate 12 side of the surface of the base electrode layer 32 and is not exposed on the surface of the base electrode layer 32.

[0047] In this embodiment, the glass 40 contains Si, Ba, and Al as components, as well as P. An insolubilization film 42 is arranged on the glass 40 so as to cover the portion exposed from the underlying electrode layer 32. That is, the insolubilization film 42 is located on the surface of the glass 40 that is exposed from the surface of the underlying electrode layer 32. The insolubilization film 42 contains compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded. The compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded, contained in the insolubilization film 42 suppress the dissolution of the glass 40 in the plating solution. In other words, when a plating layer 34 is formed on the underlying electrode layer 32 using a plating solution, the insolubilization film 42 exposed on the underlying electrode layer 32 of the glass 40 contains compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded, which are difficult to dissolve in the plating solution. Therefore, the insolubilization film 42 functions as a barrier film against the plating solution. This suppresses the erosion of the glass 40 by the plating solution.

[0048] When the glass 40 is dissolved by the plating solution, for example, the following problems occur. For example, as problems, when the base electrode layer 32 is eroded by the plating solution and the flatness of the surface of the base electrode layer 32 decreases, when the base electrode layer 32 is eroded by the plating solution and is disconnected, and when the plating solution penetrates into the laminated ceramic capacitor 10 through the eroded portion, etc. can be cited. However, in the laminated ceramic capacitor 10 having the above configuration, since the glass 40 is contained in the base electrode layer 32, the above-described problems can be suppressed. That is, since the glass 40 is suppressed from being eroded by the plating solution, it is possible to suppress a decrease in the flatness of the surface of the base electrode layer 32 due to erosion by the plating solution, suppress disconnection of the base electrode layer 32 due to erosion by the plating solution, and suppress penetration of the plating solution into the laminated ceramic capacitor 10.

[0049] Thereby, when the plating treatment is performed on the base electrode layer 32, it is possible to achieve an improvement in reliability such as suppression of poor plating adhesion to the base electrode layer 32, suppression of a decrease in the conductivity of the base electrode layer 32, and suppression of a decrease in the moisture resistance reliability of the laminated ceramic capacitor 10.

[0050] In the present embodiment, the compound in which Ba and P contained in the insolubilized film 42 are combined is barium pyrophosphate dihydrate. Barium pyrophosphate dihydrate is a substance insoluble in water, and can suppress the elution of the glass 40 into the plating solution. Further, the compound in which Ba and S contained in the insolubilized film 42 are combined is barium sulfate.

[0051] Furthermore, the laminate 12 side of the surface of the base electrode layer 32 contains glass. In other words, this glass is not exposed on the surface of the base electrode layer 32, but is located inside the base electrode layer 32. Unlike glass 40, the glass located inside the base electrode layer 32 does not contain compounds to which Ba and P are bonded. Since the glass located inside the base electrode layer 32 is not exposed on the surface of the base electrode layer 32, it is not exposed to the plating solution when forming the plating layer on the base electrode layer 32. Therefore, there is no need to form a layer to suppress erosion of the glass located inside the base electrode layer 32 by the plating solution, and no treatment for that purpose is necessary. Such glass, due to the presence of Si, Ba, and Al, can contribute to improving the adhesion between the internal electrode layer 16 and the base electrode layer 32 compared to glass 40.

[0052] Next, the first plating layer 34a and the second plating layer 34b, which are plating layers 34 placed on the base electrode layer 32, will be described with reference to Figures 1 to 3.

[0053] The first plating layer 34a is arranged to cover the first base electrode layer 32a on the first end face 12e side. Furthermore, the first plating layer 34a may be arranged to cover the first base electrode layer 32a on the first main surface 12a, the second main surface 12b, the first side surface 12c, and the second side surface 12d. However, the first plating layer 34a may be arranged only on the first base electrode layer 32a on the first end face 12e side.

[0054] The second plating layer 34b is arranged to cover the second base electrode layer 32b on the second end face 12f side. Furthermore, the second plating layer 34b may be arranged to cover the second base electrode layer 32b on the first main surface 12a, the second main surface 12b, the first side surface 12c, and the second side surface 12d side. However, the second plating layer 34b may be arranged only on the second base electrode layer 32b on the second end face 12f side.

[0055] The first plating layer 34a and the second plating layer 34b include, for example, at least one selected from Cu, Ni, Sn, Ag, Pd, Ag-Pd alloy, Au, etc.

[0056] The plating layer 34 may be formed from multiple layers. For example, the first plating layer 34a has a two-layer structure consisting of a first lower plating layer 34a1 and a first upper plating layer 34a2 covering the first lower plating layer 34a1, and the second plating layer 34b has a two-layer structure consisting of a second lower plating layer 34b1 and a second upper plating layer 34b2 covering the second lower plating layer 34b1. Preferably, the first lower plating layer 34a1 and the second lower plating layer 34b1 are Ni plating layers, and the first upper plating layer 34a2 and the second upper plating layer 34b2 are Sn plating layers.

[0057] The first and second lower plating layers 34a1 and 34b1, made of Ni plating, are used to prevent the underlying electrode layer 32 from being corroded by the solder when mounting the multilayer ceramic capacitor 10. The first and second upper plating layers 34a2 and 34b2, made of Sn plating, are used to improve the wettability of the solder when mounting the multilayer ceramic capacitor 10, thereby facilitating easier mounting.

[0058] The first and second lower plating layers 34a1 and 34b1, which are Ni plating layers, are preferably 1 μm or more and 15 μm or less in thickness. The first and second upper plating layers 34a2 and 34b2, which are Sn plating layers, are preferably 1 μm or more and 15 μm or less in thickness.

[0059] The first and second upper plating layers 34a2 and 34b2 may be omitted. Furthermore, the plating layer 34 may consist of the first and second upper plating layers 34a2 and 34b2 as the outermost layers, or other plating electrodes may be formed on the surfaces of the first and second upper plating layers 34a2 and 34b2.

[0060] The dimensions of the multilayer ceramic capacitor 10, including the laminate 12, the first external electrode 30a, and the second external electrode 30b, are defined as L in the length direction z, T in the height direction x, and W in the width direction y. The dimensions of the multilayer ceramic capacitor 10, including the laminate 12, the first external electrode 30a, and the second external electrode 30b, are defined as L, T in the height direction x, and W in the width direction y.

[0061] In the multilayer ceramic capacitor 10 shown in Figure 1, an insolubilizing film 42 is formed on the surface of the glass 40 exposed from the base electrode layer 32, having a compound to which Ba and P are bonded, and a compound to which Ba and S are bonded. This suppresses the dissolution of the glass 40 in the plating solution. Therefore, the insolubilizing film 42 functions as a barrier film against the plating solution. As a result, the glass 40 is not eroded by the plating solution, and the penetration of the plating solution into the interior of the multilayer ceramic capacitor 10 is suppressed. Thus, the reliability of the multilayer ceramic capacitor 10 can be improved.

[0062] Next, a method for manufacturing a multilayer ceramic capacitor according to the first embodiment will be described.

[0063] (Step 1) First, a dielectric sheet for the ceramic layer and a conductive paste for the internal electrode layer are prepared. The dielectric sheet and the conductive paste for the internal electrode layer contain a binder and a solvent. The binder and solvent may be known.

[0064] (Step 2) Then, a conductive paste for the internal electrode layer is printed on the dielectric sheet in a predetermined pattern, for example, by screen printing or gravure printing. This prepares a dielectric sheet with the pattern of the first internal electrode layer formed on it, and a dielectric sheet with the pattern of the second internal electrode layer formed on it.

[0065] Furthermore, regarding dielectric sheets, dielectric sheets for the outer layer that do not have the pattern of the internal electrode layer printed on them are also prepared.

[0066] A predetermined number of dielectric sheets for the outer layer, which do not have the pattern of the internal electrode layer printed on them, are stacked. On top of these, dielectric sheets with the pattern of the first internal electrode layer printed on them, and dielectric sheets with the pattern of the second internal electrode layer printed on them are sequentially stacked to form the inner layer portion 14b. On top of this inner layer portion 14b, a predetermined number of dielectric sheets for the outer layer, which do not have the pattern of the internal electrode layer printed on them, are stacked. This forms a laminated sheet having the inner layer portion 14b and the outer layer portion.

[0067] (Step 4) Next, the laminated sheets are pressed in the lamination direction by means of hydrostatic pressing or other means to produce a laminated block.

[0068] (Step 5) The laminated block is then cut to a predetermined size, thereby cutting out the laminated chips. At this time, the corners and edges of the laminated chips may be rounded by barrel polishing or the like.

[0069] (Step 6) Next, the laminated chips are fired to produce the laminated body 12. The firing temperature depends on the materials of the dielectric ceramic layer and the internal electrode layer, but it is preferably between 900°C and 1400°C. Steps 1 to 6 constitute the laminated body formation process.

[0070] (Step 7) Next, the first external electrode 30a and the second external electrode 30b are formed on the first end face 12e and the second end face 12f of the laminate 12. That is, first, a paste for the base electrode layer is applied to the first end face 12e and the second end face 12f of the laminate 12 and baked, forming the first base electrode layer 32a of the first external electrode 30a and the second base electrode layer 32b of the second external electrode 30b. The baking temperature is preferably 700°C or higher and 900°C or lower. The paste for the base electrode layer contains metal powder, which is Cu as the main component, and glass powder, which contains Si, Ba and Al as components. The metal powder and glass powder in the paste for the base electrode layer are incorporated as conductive metal and glass 40 in the base electrode layer 32 by the aforementioned baking.

[0071] (Step 8) Next, the glass 40 exposed on the surface of the base electrode layer 32 is plated with a pyrophosphate-based Cu plating solution. As a result, an insolubilized film 42 is formed on the exposed portion of the glass 40 in the base electrode layer 32. This will be explained in detail below.

[0072] A pretreatment is performed by immersing the laminate 12, on which the base electrode layer 32 is formed, in an aqueous sodium sulfate solution or an aqueous sulfuric acid solution under predetermined conditions. After this pretreatment, the laminate is immersed in a pyrophosphate-based Cu plating solution to which sulfuric acid has been added while an electric current is applied. The pyrophosphate-based Cu plating solution to which sulfuric acid has been added contains sulfate ions and a complex of Cu and pyrophosphate. The ratio of pyrophosphate ions to sulfate ions in the pyrophosphate-based Cu plating solution to which sulfuric acid has been added, namely pyrophosphate ions:sulfate ions, is preferably 1:0.1 to 1:2, and more preferably 1:0.5 to 1.5. The pyrophosphate ion content is preferably 20 g / L to 300 g / L. The Cu ion concentration is preferably 1 g / L to 40 g / L. In this way, by pre-treatment, a compound to which Ba and P are bonded, and an insolubilized film 42 containing the compound to which Ba and P are bonded, are formed on the surface of the glass 40. Subsequently, by immersing it in a Cu plating solution to which sulfuric acid is added, the formation of the insolubilized film 42 containing the compound to which Ba and P are bonded, and the compound to which Ba and P are bonded, can be maintained.

[0073] Furthermore, the pyrophosphate-based Cu plating solution may be composed of copper pyrophosphate, potassium pyrophosphate, sulfates, and additives. Alternatively, the pyrophosphate-based Cu plating solution may be composed of potassium pyrophosphate, copper sulfate, sulfates, and additives. That is, as a starting material to achieve the predetermined Cu ion concentration, pyrophosphate ion concentration, and sulfate ion concentration, copper sulfate may be used as the source of Cu, and sodium sulfate or potassium sulfate may be used as the source of sulfates.

[0074] (Step 9) Next, a plating layer 34 is formed. In this embodiment, the plating layer 34 is formed on the surface 33 of the base electrode layer 32. More specifically, a Ni plating layer and a Sn plating layer are formed on the base electrode layer 32. When performing the plating process, either electrolytic plating or electroless plating may be used, but electroless plating has the disadvantage of requiring pretreatment with a catalyst or the like to improve the plating deposition rate, which complicates the process. Therefore, it is generally preferable to use electrolytic plating. As for the plating method, it is preferable to use barrel plating.

[0075] As described above, the multilayer ceramic capacitor 10 shown in Figure 1 is manufactured.

[0076] <Second Embodiment> An example of a multilayer ceramic capacitor 110 according to the second embodiment of the present invention will be described.

[0077] Figure 5 is an external perspective view showing an example of a multilayer ceramic capacitor according to a second embodiment of the present invention. Figure 6 is a cross-sectional view taken along line II-II in Figure 5. Figure 7 is an enlarged cross-sectional view of part B of the first external electrode in the cross-sectional view shown in Figure 6. Components that are the same as or corresponding to those in Figures 1 to 4 are denoted by the same reference numerals, and detailed descriptions are omitted.

[0078] The multilayer ceramic capacitor 110 comprises a laminate 12 and a plurality of external electrodes 130.

[0079] (Laminated structure) In the multilayer ceramic capacitor 110 according to the second embodiment, the laminated structure 12 has the same configuration as the laminated structure 12 of the first embodiment of this invention shown in Figure 1.

[0080] Furthermore, the laminate 12 further includes glass 40. The glass 40 of the laminate 12 mainly contains Si and Ba. Furthermore, the glass of the laminate 12 preferably includes at least one selected from Al, B, Pd, Mg, or Li. The glass in this embodiment mainly contains Si, Ba, and Al components. In this embodiment, the glass 40 is configured such that the dissolution of the glass 40 is suppressed during the plating process of the laminate 12. Specifically, as described later, the glass 40 contains an insolubilization film 42. The insolubilization film 42 contains compounds in which Ba and P are bonded insoluble in the plating solution during the plating process, as well as compounds in which Ba and S are bonded. Therefore, in this embodiment, the insolubilization film 42 contains Si, Ba, and Al as components, as well as P.

[0081] Next, we will further explain the glass 40 contained in the laminate 12. As shown in Figure 7, a portion of the glass 40 is exposed on the surface of the laminate 12. On the other hand, there is also glass located on the side of the laminate 12 that is not exposed on the surface of the laminate 12.

[0082] In this embodiment, the glass 40 contains Si, Ba, and Al as components, as well as P. An insolubilization film 42 is arranged on the glass 40 so as to cover the portion exposed from the laminate 12. That is, the insolubilization film 42 is located on the surface of the glass 40 that is exposed from the surface of the laminate 12. The insolubilization film 42 contains compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded. The compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded, contained in the insolubilization film 42 suppress the dissolution of the glass 40 in the plating solution. In other words, when a plating layer 34 is formed on the laminate 12 using a plating solution, the insolubilization film 42 of the glass 40 that is exposed from the laminate 12 contains compounds to which Ba and P are bonded, and compounds to which Ba and P are bonded, which are difficult to dissolve in the plating solution. Therefore, the insolubilization film 42 functions as a barrier film against the plating solution. This suppresses the erosion of the glass 40 by the plating solution.

[0083] If the glass 40 is dissolved by the plating solution, the following problems may occur. For example, problems may include the lamination 12 being eroded by the plating solution, resulting in a decrease in the flatness of the surface of the lamination 12; the lamination 12 being eroded by the plating solution and breaking; and the plating solution penetrating into the multilayer ceramic capacitor 110 through the eroded portion. However, in the multilayer ceramic capacitor 110 with the above configuration, since the glass 40 is included in the lamination 12, the aforementioned problems can be suppressed. In other words, since the erosion of the glass 40 by the plating solution is suppressed, it is possible to suppress the decrease in the flatness of the surface of the lamination 12 due to erosion by the plating solution, suppress the breakage of the lamination 12 due to erosion by the plating solution, and suppress the penetration of the plating solution into the multilayer ceramic capacitor 110.

[0084] The first internal electrode layer 16a is arranged on a plurality of ceramic layers 14 and is located inside the laminate 12. The first internal electrode layer 16a has a first opposing electrode portion 26a facing the second internal electrode layer 16b, and a first drawn-out electrode portion 28a located on one end side of the first internal electrode layer 16a, extending from the first opposing electrode portion 26a to the first end face 12e of the laminate 12. The end of the first drawn-out electrode portion 28a is drawn out to the surface of the first end face 12e and is exposed from the laminate 12.

[0085] The second internal electrode layer 16b is arranged on a plurality of ceramic layers 14 and is located inside the laminate 12. The second internal electrode layer 16b has a second opposing electrode portion 26b facing the first internal electrode layer 16a, and a second drawn-out electrode portion 28b located on one end side of the second internal electrode layer 16b, extending from the second opposing electrode portion 26b to the second end face 12f of the laminate 12. The end of the second drawn-out electrode portion 28b is drawn out to the surface of the second end face 12f and is exposed from the laminate 12.

[0086] The external electrode 130 is preferably composed of a Cu plating layer 131, a base electrode layer 132, and a plating layer 134. In this embodiment, the external electrode 130 includes a Cu plating layer 131, a base electrode layer 132 disposed on the Cu plating layer 131, and a plating layer 134 disposed on the base electrode layer 132. The plating layer 134 includes a first plating layer 134a and a second plating layer 134b. The first external electrode 130a has a first Cu plating layer 131a, a first base electrode layer 132a disposed on the first Cu plating layer 131a, a first lower plating layer 134a1 disposed on the first base electrode layer 132a, and a first upper plating layer 134a2 disposed on the first lower plating layer 134a1. The second external electrode 130b includes a second Cu plating layer 131b, a second base electrode layer 132b disposed on the second Cu plating layer 131b, a second lower plating layer 134b1 disposed on the second base electrode layer 132b, and a second upper plating layer 134b2 disposed on the second lower plating layer 134b1.

[0087] The first Cu plating layer 131a is connected to the first internal electrode layer 16a and is positioned on the surface of the first end face 12e. In this case, the first Cu plating layer 131a is electrically connected to the first extraction electrode portion 28a of the first internal electrode layer 16a.

[0088] The second Cu plating layer 131b is connected to the second internal electrode layer 16b and is positioned on the surface of the second end face 12f. In this case, the second Cu plating layer 131b is electrically connected to the second extraction electrode portion 28b of the second internal electrode layer 16b.

[0089] The multilayer ceramic capacitor 110 shown in Figure 5 provides the same effects as the multilayer ceramic capacitor 10 described above.

[0090] Next, a method for manufacturing a multilayer ceramic capacitor according to the second embodiment will be described. Steps 1 to 6, which are the laminate formation steps, are the same as those for the multilayer ceramic capacitor according to the first embodiment, so their explanation will be omitted.

[0091] (Step 7A) Next, a Cu plating layer 131 is formed on the laminate 12 so as to cover the internal electrode layer 16 that is exposed on the surface. The Cu plating layer 131 is formed by electroplating with a pyrophosphate-based Cu plating solution. At this time, the laminate 12 is heat-treated after plating to remove any remaining moisture in the plating film and at the interface between the laminate 12 and the Cu plating layer 131. In addition, the glass 40 is plated with a pyrophosphate-based Cu plating solution. As a result, an insolubilized film 42 is formed on the exposed portion of the glass 40 in the laminate 12. This will be explained in detail below.

[0092] A pretreatment is performed by immersing the laminate 12 in an aqueous sodium sulfate solution or an aqueous sulfuric acid solution under predetermined conditions. After this pretreatment, it is immersed in a pyrophosphate-based Cu plating solution with added sulfuric acid while an electric current is applied. The pyrophosphate-based Cu plating solution with added sulfuric acid contains sulfate ions and a complex of Cu and pyrophosphate. The ratio of pyrophosphate ions to sulfate ions in the pyrophosphate-based Cu plating solution with added sulfuric acid, namely pyrophosphate ions:sulfate ions, is preferably 1:0.1 to 1:2, and more preferably 1:0.5 to 1.5. The pyrophosphate ion content is preferably 20 g / L to 300 g / L. The Cu ion concentration is preferably 1 g / L to 40 g / L. In this way, by pre-treatment, a compound to which Ba and P are bonded, and an insolubilized film 42 containing the compound to which Ba and P are bonded, are formed on the surface of the glass 40. Subsequently, by immersing it in a Cu plating solution to which sulfuric acid is added, the formation of the insolubilized film 42 containing the compound to which Ba and P are bonded, and the compound to which Ba and P are bonded, can be maintained.

[0093] Furthermore, the pyrophosphate-based Cu plating solution may be composed of copper pyrophosphate, potassium pyrophosphate, sulfates, and additives. Alternatively, the pyrophosphate-based Cu plating solution may be composed of potassium pyrophosphate, copper sulfate, sulfates, and additives. That is, as a starting material to achieve the predetermined Cu ion concentration, pyrophosphate ion concentration, and sulfate ion concentration, copper sulfate may be used as the source of Cu, and sodium sulfate or potassium sulfate may be used as the source of sulfates.

[0094] (Step 8A) Next, a paste for the base electrode layer is applied and baked to cover the Cu plating layer 131 which is arranged on both end faces of the laminate 12, thereby forming the base electrode layer 132. The baking temperature is preferably 700°C or higher and 900°C or lower. The paste for the base electrode layer contains metal powder, which is Cu as the main component, and glass powder, which contains Si, Ba and Al as components. The metal powder and glass powder in the paste for the base electrode layer are incorporated as conductive metal and glass 40 in the base electrode layer 132 by the aforementioned baking.

[0095] (Step 9A) Next, a plating layer 134 is formed. In this embodiment, the plating layer 134 is formed on the surface of the base electrode layer 132. More specifically, a Ni plating layer and a Sn plating layer are formed on the base electrode layer 132. When performing the plating process, either electrolytic plating or electroless plating may be used, but electroless plating has the disadvantage of requiring pretreatment with a catalyst or the like to improve the plating deposition rate, which complicates the process. Therefore, it is generally preferable to use electrolytic plating. As for the plating method, it is preferable to use barrel plating.

[0096] As described above, the multilayer ceramic capacitor 110 shown in Figure 5 is manufactured.

[0097] <Experimental Example> An experiment was conducted to confirm the effect of the multilayer ceramic capacitor according to the present invention.

[0098] (1) Evaluation of treatment with Cu plating solution A model evaluation was performed using glass glaze fired on an alumina substrate. A glass glaze with a thickness of 5 μm, a length of 1 cm, and a width of 1.2 cm was prepared. Sample 1-1 was prepared by immersing this glass glaze in a pyrophosphate-based Cu plating solution with added sulfuric acid at 55°C for 60 minutes while energized, and Sample 1-2 was prepared by immersing it in a pyrophosphate-based Cu plating solution without added sulfuric acid at 55°C for 60 minutes while energized.

[0099] Sample 1-1, a pyrophosphate-based Cu plating solution with added sulfuric acid, contains 185 g / L of sodium sulfate, 30 g / L of copper pyrophosphate, and 170 g / L of potassium pyrophosphate, with a sulfate ion concentration of 125 g / L, a Cu ion concentration of 10.3 g / L, and a pyrophosphate ion concentration of 90 g / L. Sample 1-2, a pyrophosphate-based Cu plating solution without added sulfuric acid, contains 30 g / L of copper pyrophosphate and 170 g / L of potassium pyrophosphate, with a Cu ion concentration of 10.3 g / L and a pyrophosphate ion concentration of 90 g / L.

[0100] Next, the amount of glass eluted in each immersion solution was measured, and the cross-section of the glass glaze was observed. For the observation, the cross-section of the glass glaze was mapped using SEM-EDX to observe the composition of the insolubilized film 42 located on the surface of the glass 40. From the ICP (emission spectroscopy) results, it became clear that the amount of glass eluted decreased because it contained sulfate ions in the pyrophosphate-based Cu plating solution with added sulfuric acid, which was sample 1-1. It was also confirmed that the amount of glass eluted decreased as the sulfate ion concentration in the pyrophosphate-based Cu plating solution with added sulfuric acid increased. Furthermore, from the SEM-EDX results, it was confirmed that a film containing sulfur was formed on the surface of the glass glaze immersed in the pyrophosphate-based Cu plating solution with added sulfuric acid. This film containing sulfur is presumed to be barium sulfate, and since barium sulfate is insoluble in water, it is presumed that the amount of glass eluted decreased. On the other hand, the presence of a film containing sulfur was not confirmed on the surface of the glass glaze immersed in the pyrophosphate-based Cu plating solution without added sulfuric acid, which was sample 1-2.

[0101] (2) Evaluation of treatment with Cu plating solution including pretreatment A model evaluation was performed using glass glaze fired on an alumina substrate. A glass glaze with a thickness of 5 μm, a length of 1 cm, and a width of 1.2 cm was prepared. Sample 2-1 was prepared by pretreating this glass glaze with a 2.5 wt% sodium sulfate aqueous solution at 55°C for 60 minutes, and Sample 2-2 was prepared by pretreating it with a 4 wt% sulfuric acid aqueous solution at 25°C for 3 minutes. At this time, it was confirmed that barium sulfate was formed in each glass glaze.

[0102] Then, the amount of glass eluted in each immersion solution was measured, and the cross-section of the glass glaze was observed. For the observation, the cross-section of the glass glaze was mapped using SEM-EDX to observe the composition of the insolubilized film 42 located on the surface of the glass 40. Samples were prepared in which the above-mentioned sample 2-1 or sample 2-2 was treated with a Cu plating solution to which sulfuric acid was added (sample 2-3), and samples were prepared in which the above-mentioned sample 2-1 or sample 2-2 was treated with a Cu plating solution to which sulfuric acid was not added (sample 2-4). The pyrophosphate-based Cu plating solution to which sulfuric acid was added was the same as that used for sample 1-1, and the pyrophosphate-based Cu plating solution to which sulfuric acid was not added was the same as that used for sample 1-2.

[0103] SEM-EDX results showed that in samples 2-3, even after the above-described pretreatment and subsequent immersion in a Cu plating solution with added sulfuric acid for 60 minutes under current, barium sulfate formed on the surface of the glass glaze was still observed. ICP (emission spectroscopy) results revealed that the amount of glass eluted in this glass glaze was significantly reduced. This is thought to be because an insoluble barium sulfate film 42 was formed on the surface of the glass 40 during the pretreatment stage, and this insoluble film 42 was maintained by immersion in the Cu plating solution with added sulfuric acid.

[0104] On the other hand, in sample 2-4, even after performing the above-described pretreatment and forming a barium sulfate film, it became clear that barium sulfate leached out when immersed in a pyrophosphate-based Cu plating solution without added sulfuric acid. Therefore, it is thought that glass will leach out even when combined with pretreatment in a pyrophosphate-based Cu plating solution without added sulfuric acid.

[0105] (3) Multilayer ceramic capacitors to be used as evaluation samples for the laminate were ground into powder. 0.5 g of this powder was used to prepare three samples: Sample 3-1, which was immersed in 20 g of pyrophosphate-based Cu plating solution with added sulfuric acid; Sample 3-2, which was immersed in 20 g of pyrophosphate-based Cu plating solution without added sulfuric acid; and Sample 3-3, which was immersed in 20 g of pyrophosphate-based Cu plating solution without added sulfuric acid, which had a lower pyrophosphate ion concentration than the pyrophosphate-based Cu plating solution used in Sample 3-2.

[0106] The sulfuric acid-added pyrophosphate-based Cu plating solution used in Sample 3-1 was the same as that used in Sample 1-1. The sulfuric acid-free pyrophosphate-based Cu plating solution used in Sample 3-2 contained 90 g / L of copper pyrophosphate and 350 g / L of potassium pyrophosphate, with a Cu ion concentration of 30.5 g / L and a pyrophosphate ion concentration of 184 g / L. The sulfuric acid-free pyrophosphate-based Cu plating solution used in Sample 3-3 was the same as that used in Sample 1-2.

[0107] Sample 3-1 suggested that adding sulfuric acid to the pyrophosphate-based Cu plating solution formed an insolubilizing film 42 on the glass 40 contained in the laminate, thereby reducing the amount of glass eluted from the laminate. In other words, it was suggested that adding sulfuric acid to the Cu plating solution is also advantageous in terms of the erosive properties of the laminate against glass. On the other hand, in both Sample 3-2 and Sample 3-3, since sulfuric acid was not added to the pyrophosphate-based Cu plating solution, it was confirmed that the reduction in the amount of glass eluted from the laminate could not be prevented.

[0108] <Modification> In the above embodiment, a two-terminal multilayer ceramic capacitor having two terminals, a first external electrode 30a and a second external electrode 30b, was described as a multilayer ceramic electronic component. However, the present invention is not limited to a two-terminal multilayer ceramic capacitor and is applicable to multilayer ceramic electronic components having external electrodes. For example, the present invention may be applied to a three-terminal multilayer ceramic capacitor. The three-terminal multilayer ceramic capacitor has a laminate 12 similar to that in the above embodiment and first to fourth external electrodes. The internal electrode layer 16 has a first internal electrode layer drawn out to the first end face 12e and the second end face 12f, and a second internal electrode layer drawn out to the first side surface 12c and the second side surface 12d. The first external electrode is arranged on the first end face 12e of the laminate 12. The first external electrode is electrically connected to the first internal electrode layer exposed on the first end face 12e of the laminate 12. The second external electrode is arranged on the second end face 12f of the laminate 12. The second external electrode is electrically connected to the first internal electrode layer exposed on the second end face 12f of the laminate 12. A third external electrode is positioned on the first side surface 12c of the laminate 12. The third external electrode is electrically connected to the second internal electrode layer exposed on the first side surface 12c of the laminate 12. A fourth external electrode is positioned on the second side surface 12d of the laminate 12. The fourth external electrode is electrically connected to the second internal electrode layer exposed on the second side surface 12d of the laminate 12.

[0109] Each of the first to fourth external electrodes is formed by sequentially laminating a base electrode layer, a resin electrode layer, and a plating layer, similar to the embodiment described above. The resin electrode layer includes a conductive filler and a resin.

[0110] As described above, embodiments of the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, without departing from the scope of the technical idea and objectives of the present invention, various modifications can be made to the embodiments described above in terms of mechanism, shape, material, quantity, position or arrangement, etc., and these are included in the present invention.

[0111] 10: Multilayer ceramic capacitor 12: Laminate 12a: First main surface 12b: Second main surface 12c: First side surface 12d: Second side surface 12e: First end surface 12f: Second end surface 14: Ceramic layer 14a, 14b: Outer layer, inner layer 16: Internal electrode layer 16a, 16b: First, second internal electrode layer 26a, 26b: First, second opposing electrode portion 28a, 28b: First, second lead electrode portion 30, 130: External electrode 30a, 30b, 130a, 130b: First, second external electrode 131: Cu plating layer 131a, 131b: First, second Cu plating layer 32, 132 : Underlay electrode layer 32a, 32b, 132a, 132b: First and second underlay electrode layers 34, 134: Plating layer 34a, 34b, 134a, 134b: First and second plating layers 34a1, 34b1, 134a1, 134b1: First and second lower plating layers 34a2, 34b2, 134a2, 134b2: First and second upper plating layers 40: Glass 42: Insolubilized film x: Height direction y: Width direction z: Length direction

Claims

1. A method for manufacturing a multilayer ceramic capacitor, comprising the steps of: preparing a laminate including a plurality of ceramic layers and a plurality of internal electrode layers; forming a base electrode layer including a conductive metal and glass on the laminate; performing a plating treatment on the base electrode layer with a pyrophosphate-based Cu plating solution to form an insolubilization film on the surface of the glass; and forming a plating layer on the base electrode layer to form an external electrode in which the base electrode layer and the plating layer are laminated, wherein the pyrophosphate-based Cu plating solution contains a complex of sulfate ions, Cu ions and pyrophosphate ions.

2. The method for manufacturing a multilayer ceramic capacitor according to claim 1, wherein the content ratio of sulfate ions and pyrophosphate ions contained in the pyrophosphate-based Cu plating solution is 1:0.1 to 1:

2.

3. The method for manufacturing a multilayer ceramic capacitor according to claim 1 or claim 2, wherein the pyrophosphate ion content in the pyrophosphate-based Cu plating solution is 20 g / L or more and 300 g / L or less.

4. A multilayer ceramic capacitor comprising: a laminate including a plurality of ceramic layers and a plurality of internal electrode layers; and an external electrode connected to the plurality of internal electrode layers in the portion where the plurality of internal electrode layers are exposed in the laminate, wherein the external electrode includes a base electrode layer in contact with the laminate; the base electrode layer includes a conductive metal and glass having Si and Ba; and the surface of the glass exposed from the base electrode layer includes an insolubilized film having a compound to which Ba and P are bonded and a compound to which Ba and S are bonded.

5. A method for manufacturing a multilayer ceramic capacitor, comprising the steps of: preparing a laminate including a plurality of ceramic layers, a plurality of internal electrode layers, and glass; forming a Cu plating layer on the laminate using a pyrophosphate-based Cu plating solution; and forming an external electrode in which the Cu plating layer, the base electrode layer, and the plating layer are laminated by forming a base electrode layer and a plating layer on the Cu plating layer, wherein the pyrophosphate-based Cu plating solution contains a complex of sulfate ions, Cu ions, and pyrophosphate ions, and in the step of forming the Cu plating layer on the laminate, an insolubilization film is formed on the surface of the glass.

6. The method for manufacturing a multilayer ceramic capacitor according to claim 5, wherein the content ratio of sulfate ions and pyrophosphate ions contained in the pyrophosphate-based Cu plating solution is 1:0.1 to 1:

2.

7. The method for manufacturing a multilayer ceramic capacitor according to claim 5 or claim 6, wherein the pyrophosphate ion content in the pyrophosphate-based Cu plating solution is 20 g / L or more and 300 g / L or less.

8. A multilayer ceramic capacitor comprising: a laminate including a plurality of ceramic layers, a plurality of internal electrode layers, and glass; and an external electrode connected to the plurality of internal electrode layers in the portion of the plurality of internal electrode layers that is exposed in the laminate, wherein the external electrode includes a Cu plating layer in contact with the laminate, and the surface of the glass exposed from the laminate includes an insolubilized film having a compound to which Ba and P are bonded and a compound to which Ba and S are bonded.

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