Multilayer ceramic component

Abstract

The present invention provides a multilayer ceramic component in which an external electrode has a thickness that does not inhibit ease of mounting even in cases in which a housing in which the multilayer ceramic component is mounted is reduced in size. This multilayer ceramic component 1 comprises: a multilayer body 2; and external electrodes 20 which are provided on a first end surface and a second end surface, and are connected to internal electrode layers 10. The external electrodes 20 each comprise: a base film 21 that extends to a first main surface and a second main surface and is in contact with the internal electrode layers 10; an inner plating film 24 that is in contact with the base film 21; and an outer plating film 25 that is in contact with the inner plating film 24. The film thickness of the base film 21 is greater than that of the inner plating film 24 and that of the outer plating film 25. The film thickness of the base film 21 is 1.4 to 3.0 times the film thickness of the inner plating film 24. The film thickness of the base film 21 is 1.4 to 3.0 times the film thickness of the outer plating film 25. The film thickness of the base film 21 is 0.4 to 0.6 times the total film thickness of the base film 21, the inner plating film 24 and the outer plating film 25. The film thickness of the inner plating film 24 is 0.2 to 0.3 times the total film thickness of the base film 21, the inner plating film 24, and the outer plating film 25, and the film thickness of the outer plating film 25 is 0.2 to 0.3 times the total film thickness of the base film 21, the inner plating film 24, and the outer plating film 25.

Description

Multilayer ceramic parts

[0001] The present invention relates to a multilayer ceramic component, and in particular to a multilayer ceramic capacitor.

[0002] In the multilayer ceramic capacitor, the external electrodes have a base electrode and a plating film, and the plating film consists of a Ni plating film covering the base electrode and a Sn plating film covering the Ni plating film. The base electrode, the Ni plating film, and the Sn plating film have a constant thickness.

[0003] Japanese Patent Application Laid-Open No. 2020-174110

[0004] The base electrode layer in Patent Document 1 is designed to be thick enough to ensure connection reliability with the internal electrode layer provided inside the laminate, the Ni plating film covering the base electrode layer is designed to be thick enough to prevent solder erosion during mounting, and the Sn plating film covering the Ni plating film is designed to be thick enough to ensure solder wettability.

[0005] However, in recent years, the housings in which multilayer ceramic capacitors are mounted have become smaller, and the smaller housings have reduced the area in which the multilayer ceramic capacitor can be mounted. To accommodate the mounting area of ​​the smaller housings, the size of the multilayer ceramic capacitors has been reduced. However, reducing the size of the inner layer makes it difficult to ensure the desired capacitance. Therefore, the thicknesses of the base electrode layer, Ni plating film, and Sn plating film, which do not contribute to capacitance formation, have become an issue in terms of mountability in the smaller housings.

[0006] Therefore, an object of the present invention is to provide a multilayer ceramic capacitor that ensures connection reliability and has external electrodes thick enough not to impair mountability, even when the housing in which the multilayer ceramic capacitor is mounted is made smaller.

[0007] The multilayer ceramic component of the present invention is a multilayer ceramic component having a laminate including a plurality of laminated dielectric layers and a plurality of internal electrode layers, the laminate having a first main surface and a second main surface opposing each other in the lamination direction, a first side surface and a second side surface opposing each other in a width direction perpendicular to the lamination direction, and a first end surface and a second end surface opposing each other in a length direction perpendicular to the lamination direction and the width direction, and external electrodes provided on the first end surface and the second end surface and connected to the internal electrode layers, the external electrodes extending to the first main surface and the second main surface, and including an undercoat film in contact with the internal electrode layers, an inner plating film in contact with the undercoat film, and an inner plating and an outer plating film in contact with the film, the thickness of the base film being greater than that of the inner plating film and the outer plating film, the thickness of the base film being 1.4 to 3.0 times the thickness of the inner plating film, the thickness of the base film being 1.4 to 3.0 times the thickness of the outer plating film, the thickness of the base film being 0.4 to 0.6 times the total thickness of the base film, the inner plating film, and the outer plating film, the thickness of the inner plating film being 0.2 to 0.3 times the total thickness of the base film, the inner plating film, and the outer plating film, and the thickness of the outer plating film being 0.2 to 0.3 times the total thickness of the base film, the inner plating film, and the outer plating film.

[0008] According to the present invention, it is possible to provide a multilayer ceramic component that ensures connection reliability and has an external electrode thickness that does not impair mountability, even when the housing in which the multilayer ceramic component is mounted is made smaller.

[0009] 1 is a perspective view of a multilayer ceramic part according to an embodiment of the present invention, a cross-sectional view taken along line II in FIG. 1, a cross-sectional view taken along line IIA-IIA in FIG. 1, and a cross-sectional view taken along line IIB-IIB in FIG.

[0010] First Embodiment Hereinafter, an example of a multilayer ceramic component 1 according to the present invention will be described with reference to the accompanying drawings. In the following description, the multilayer ceramic component 1 will be described as a multilayer ceramic capacitor.

[0011] (External Shape of Multilayer Ceramic Component) The external appearance of the multilayer ceramic component 1 will be outlined with reference to Fig. 1. Fig. 1 is a perspective view showing the multilayer ceramic component 1 of this embodiment. The multilayer ceramic component 1 includes a laminate 2 and external electrodes 20. The external electrodes 20 include a first external electrode 20a and a second external electrode 20b.

[0012] (Definition of Directions) The drawings show an L direction, a W direction, and a T direction. The L direction is the length direction L of the multilayer ceramic component 1. The W direction is the width direction W of the multilayer ceramic component 1. The T direction is the stacking direction T of the multilayer ceramic component 1. Therefore, the cross section shown in FIG. 2 is called an LT cross section, and the cross sections shown in FIGS. 3A and 3B are called WT cross sections. The length direction L, the width direction W, and the stacking direction T do not necessarily have to be perpendicular to each other. The length direction L, the width direction W, and the stacking direction T may intersect each other.

[0013] (External Shape of Laminate) The laminate 2 has a substantially rectangular parallelepiped shape. The laminate 2 has two main surfaces 3, two side surfaces 4, and two end surfaces 5. The main surfaces 3 are surfaces facing the stacking direction T. The side surfaces 4 are surfaces facing the width direction W. The end surfaces 5 are surfaces facing the length direction L. One of the two main surfaces 3 is a first main surface 3a, and the other is a second main surface 3b. One of the two side surfaces 4 is a first side surface 4a, and the other is a second side surface 4b. One of the two end surfaces 5 is a first end surface 5a, and the other is a second end surface 5b.

[0014] It is preferable that the ridges and corners of the laminate 2 are rounded. A ridge is a portion where two surfaces of the laminate 2 intersect. A corner is a portion where three surfaces of the laminate 2 intersect. The size of the laminate 2 is not particularly limited.

[0015] (Structure of the Laminate) The laminate 2 includes a plurality of dielectric layers 7 and a plurality of internal electrode layers 10. The internal structure of the laminate 2 will be described below with reference to a cross-sectional view of the laminate 2.

[0016] (Internal Structure of Laminate (LT Cross Section)) The internal structure of the laminate 2 will be described with reference to Fig. 2. Fig. 2 is a cross section taken along line I-I in Fig. 1. Fig. 2 shows the LT cross section of the multilayer ceramic component 1. In the laminate 2, the plurality of dielectric layers 7 and the plurality of internal electrode layers 10 are stacked on top of each other in the stacking direction T.

[0017] (Dielectric Layers) The dielectric layers 7 can be classified into outer dielectric layers 7a and inner dielectric layers 7b. The inner dielectric layers 7b are dielectric layers 7 located between the internal electrode layers 10. The outer dielectric layers 7a are dielectric layers 7 located between the first main surface 3a and the internal electrode layer 10 closest to the first main surface 3a, and between the second main surface 3b and the internal electrode layer 10 closest to the second main surface 3b.

[0018] (Number of Dielectric Layers) The number of dielectric layers 7 stacked in the laminate 2 can be, for example, 5 to 2000. This number of dielectric layers 7 includes the number of outer dielectric layers 7 a and the number of inner dielectric layers 7 b.

[0019] (Material of Dielectric Layer) The material of the dielectric layer 7 is, for example, BaTiO ３ , CaTiO ３ , SrTiO ３ , CaZrO ３ It is possible to use a dielectric ceramic made of the above-mentioned main components. It is also possible to use a material in which a subcomponent such as a Mn compound, an Fe compound, a Cr compound, a Co compound, or a Ni compound is added to these main components.

[0020] (Thickness of Dielectric Layer) The thickness of the dielectric layer 7 can be, for example, 0.3 μm or more and 100 μm or less. The outer dielectric layer 7a may be a single layer or a plurality of layers.

[0021] (Internal electrode layers) The internal electrode layers 10 can be classified into first internal electrode layers 10a and second internal electrode layers 10b. The first internal electrode layer 10a is an internal electrode layer 10 connected to the first external electrode 20a. The second internal electrode layer 10b is an internal electrode layer 10 connected to the second external electrode 20b. The first internal electrode layer 10a extends from the first end face 5a toward the second end face 5b. The second internal electrode layer 10b extends from the second end face 5b toward the first end face 5a.

[0022] (Facing portion and lead-out portion) The first internal electrode layer 10a and the second internal electrode layer 10b each have a facing electrode portion 11 and a lead-out electrode portion 12. The facing electrode portion 11 is a portion of the internal electrode layer 10 where the first internal electrode layer 10a and the second internal electrode layer 10b face each other in the stacking direction T. The lead-out electrode portion 12 is a portion of the internal electrode layer 10 that is led out from the facing electrode portion 11 to the first end face 5a or the second end face 5b of the laminate 2.

[0023] The opposing electrode portion 11 of the first internal electrode layer 10a is referred to as the first opposing electrode portion 11a. The lead electrode portion 12 of the first internal electrode layer 10a is referred to as the first lead electrode portion 12a. The first lead electrode portion 12a is a portion that is led out from the first opposing electrode portion 11a to the first end face 5a of the laminate 2.

[0024] Similarly, the opposing electrode portion 11 of the second internal electrode layer 10b is referred to as the second opposing electrode portion 11b. The lead electrode portion 12 of the second internal electrode layer 10b is referred to as the second lead electrode portion 12b. The second lead electrode portion 12b is a portion that is led out from the second opposing electrode portion 11b to the second end face 5b of the laminate 2.

[0025] (Number of Internal Electrode Layers) The number of the internal electrode layers 10 can be, for example, from 10 to 2000. This number of the internal electrode layers 10 includes the number of the first internal electrode layers 10a and the number of the second internal electrode layers 10b.

[0026] (Thickness of Internal Electrode Layer) The thickness of the internal electrode layer 10 can be, for example, 0.1 μm or more and 5.0 μm or less, preferably 0.2 μm or more and 2.0 μm or less. When the thickness of the internal electrode layer 10 is 0.5 μm or more, a plating film is likely to grow when the metal layer of the external electrode 20 is formed by plating.

[0027] (Material of the internal electrode layer) The material of the internal electrode layer 10 can be, for example, metals such as Ni, Cu, Ag, Pd, and Au, alloys of Ni and Cu, alloys of Ag and Pd, etc. In addition, the material of the internal electrode layer 10 may contain dielectric particles of the same composition as the ceramic contained in the dielectric layer 7.

[0028] (External Electrodes) The external electrodes 20 include a first external electrode 20a and a second external electrode 20b. The first external electrode 20a is an external electrode 20 arranged on the first end surface 5a of the laminate 2. The first external electrode 20a is electrically connected to the first internal electrode layer 10a. The second external electrode 20b is an external electrode 20 arranged on the second end surface 5b of the laminate 2. The second external electrode 20b is electrically connected to the second internal electrode layer 10b.

[0029] (External electrodes on each surface) The external electrode 20 extends from one end surface 5 to parts of the two main surfaces 3 and parts of the two side surfaces 4. The part of the external electrode 20 that is arranged on the end surface 5 is referred to as an end surface external electrode 27. The part of the external electrode 20 that is arranged on parts of the main surfaces 3 is referred to as a main surface external electrode 28. The part of the external electrode 20 that is arranged on parts of the side surfaces 4 is referred to as a side surface external electrode 29.

[0030] (End Face External Electrode) More specifically, the portion of the first external electrode 20a that is arranged on the first end face 5a is referred to as the first end face external electrode 27a, and the portion of the second external electrode 20b that is arranged on the second end face 5b is referred to as the second end face external electrode 27b.

[0031] (Principal Surface External Electrodes) Of the first external electrode 20a and the second external electrode 20b, the portion arranged on a part of the first principal surface 3a is referred to as a first principal surface external electrode 28a. Also, of the first external electrode 20a and the second external electrode 20b, the portion arranged on a part of the second principal surface 3b is referred to as a second principal surface external electrode 28b.

[0032] (Side surface external electrode) The side surface external electrode 29 is similar to the main surface external electrode 28. Of the first external electrode 20a and the second external electrode 20b, the portion arranged on a part of the first side surface 4a is referred to as the first side surface external electrode 29a. Also, of the first external electrode 20a and the second external electrode 20b, the portion arranged on a part of the second side surface 4b is referred to as the second side surface external electrode 29b.

[0033] (Layer Structure of External Electrodes) The layer structure of the external electrode 20 will be described with reference to FIGS. 2, 3A, and 3B. FIG. 3A is a cross-sectional view taken along line IIA-IIA in FIG. 1, and FIG. 3B is a cross-sectional view taken along line IIB-IIB in FIG. 1. The external electrode 20 includes an undercoat film 21 and a plating film. The plating film includes an inner plating film 24 and an outer plating film 25. These layers are arranged in this order from the end surface 5 of the laminate 2: undercoat film 21, inner plating film 24, outer plating film 25. More specifically, the first external electrode 20a includes a first undercoat film 21a, a first inner plating film 24a, and a first outer plating film 25a. Similarly, the second external electrode 20b includes a second undercoat film 21b, a second inner plating film 24b, and a second outer plating film 25b.

[0034] (Undercoat film) The first undercoat film 21a is composed of a first main surface undercoat film 31 arranged on the first main surface 3a and the second main surface 3b of the laminate 2, a first end surface undercoat film 51 arranged on the first end surface 5a of the laminate 2, and a first side surface undercoat film 71 arranged on the first side surface 4a and the second side surface 4b of the laminate 2.

[0035] Similarly, the second undercoat film 21b is composed of a second main surface undercoat film 41 arranged on the first main surface 3a and the second main surface 3b of the laminate 2, a second end surface undercoat film 61 arranged on the second end surface 5b of the laminate 2, and a second side surface undercoat film 81 arranged on the first side surface 4a and the second side surface 4b of the laminate 2.

[0036] (Baked Layer) The first undercoat film 21a and the second undercoat film 21b are configured as baked layers. The baked layers contain a glass component and a metal. The glass component includes at least one selected from B, Si, Ba, Mg, Al, Li, etc. The metal includes at least one selected from Cu, Ni, Ag, Pd, Ag-Pd alloy, Au, etc. The baked layer may be a multi-layered layer. The baked layer is formed by applying a conductive paste containing a glass component and a metal to the laminate 2 and then baking it. This baking, i.e., firing, may be performed simultaneously with the firing of the internal electrode layers 10, or may be fired separately after the firing of the internal electrode layers 10.

[0037] (Plating Film) The plating film on the base film 21 will now be described. As described above, in this embodiment, the plating film includes the inner plating film 24 and the outer plating film 25. That is, the plating film includes two layers. However, the plating film may be a single layer or a multi-layer structure of three or more layers.

[0038] When the plating film is two layers, it is preferable that the layers are Ni and Sn plated from the bottom up. In this case, the Ni plated film is the inner plating film 24 and the Sn plated film is the outer plating film 25.

[0039] (Internal plating film) The first internal plating film 24a is composed of a first internal main surface plating film 34 arranged on the first main surface base film 31, a first internal end surface plating film 54 arranged on the first internal end surface base film 51, and a first internal side surface plating film 74 arranged on the first internal side surface base film 71.

[0040] Similarly, the second inner plating film 24b is composed of a second inner main surface plating film 44 arranged on the second main surface base film 41, a second inner end surface plating film 64 arranged on the second inner end surface base film 61, and a second inner side surface plating film 84 arranged on the second inner side surface base film 81.

[0041] (External plating film) The first external plating film 25a is composed of a first external main surface plating film 35 arranged on the first internal main surface plating film 34, a first external end surface plating film 55 arranged on the first internal end surface plating film 54, and a first external side surface plating film 75 arranged on the first internal side surface plating film 74.

[0042] The second outer plating film 25b is composed of a second outer main surface plating film 45 arranged on the second inner main surface plating film 44, a second outer end surface plating film 65 arranged on the second inner end surface plating film 64, and a second outer side surface plating film 85 arranged on the second inner side surface plating film 84.

[0043] The plating films, such as the inner plating film 24 and the outer plating film 25, preferably contain at least one selected from metals such as Cu, Ni, Ag, Pd, Au, and Sn, and alloys such as Ag-Pd alloys. As mentioned above, the inner plating film 24 is preferably a Ni plating film, and the outer plating film 25 is preferably a Sn plating film. However, the inner plating film 24 and the outer plating film 25 are not limited to Ni plating film and Sn plating film.

[0044] The Ni plating film can prevent the undercoat film 21 from being eroded by solder when mounting the multilayer ceramic component 1. On the other hand, the Sn plating film can improve the wettability of the solder when mounting the multilayer ceramic component 1, making mounting easier. Therefore, by using an Sn plating film for the outer plating film 25, the wettability of the solder to the external electrodes 20 can be improved.

[0045] 3A and 3B , the WT cross section of the laminate 2 will be described. In the WT cross section of the laminate 2 at the portion where the external electrodes 20 are provided, the four surfaces of the laminate 2 are covered with the external electrodes 20. Specifically, a first main surface external electrode 28a is provided on the first main surface 3a of the laminate 2, and similarly, a second main surface external electrode 28b is provided on the second main surface 3b, a first side surface external electrode 29a is provided on the first side surface 4a, and a second side surface external electrode 29b is provided on the second side surface 4b. The first main surface external electrode 28a, the second main surface external electrode 28b, the first side surface external electrode 29a, and the second side surface external electrode 29b are continuous.

[0046] (Thickness of External Electrodes) (Claim 1) The multilayer ceramic component 1 of the present invention is characterized by the thickness of the external electrodes 20. As shown in Figure 4, the thickness of the base film 21 is greater than that of the inner plating film 24 and the outer plating film 25. Specific dimensions will be described later. The dimensional ratios of each part differ from the actual dimensional ratios.

[0047] (Thickness of Each Layer) As described above, the external electrode 20 includes multiple layers. Specifically, the external electrode 20 includes the base film 21, the inner plating film 24, and the outer plating film 25. Therefore, the thickness of the external electrode 20 is the sum of the thicknesses of the individual layers. In this embodiment, as an example of a method for adjusting the thicknesses of the base film 21, the inner plating film 24, and the outer plating film 25, a method will be described.

[0048] The base film 21 on the first main surface external electrode 28a is referred to as a first main surface base film 31. The inner plating film 24 on the first main surface external electrode 28a is referred to as a first main surface inner plating film 34. The outer plating film 25 on the first main surface external electrode 28a is referred to as a first main surface outer plating film 35.

[0049] Similarly, for the second main surface external electrode 28b, the base film 21 in the second main surface external electrode 28b is referred to as a second main surface base film 41. The inner plating film 24 in the second main surface external electrode 28b is referred to as a second main surface inner plating film 44. The outer plating film 25 in the second main surface external electrode 28b is referred to as a second main surface outer plating film 45.

[0050] The thickness of the first main surface external electrode 28a is the sum of the thickness of the first main surface undercoat film 31, the thickness of the first main surface inner plating film 34, and the thickness of the first main surface outer plating film 35. Similarly, the thickness of the second main surface external electrode 28b is the sum of the thickness of the second main surface undercoat film 41, the thickness of the second main surface inner plating film 44, and the thickness of the second main surface outer plating film 45. The thickness of the external electrode 20 in the length direction on the first end face and the second end face and the thickness of the external electrode 20 in the width direction on the first side face and the second side face are also the sum of the same thicknesses, although not shown by reference numerals.

[0051] (Effect) The thickness of the external electrode 20 in the stacking direction on the first principal surface and the second principal surface, the thickness of the external electrode 20 in the longitudinal direction on the first end face and the second end face, and the thickness of the external electrode 20 in the width direction on the first side face and the second side face are small, so that a multilayer ceramic capacitor that is compatible with a miniaturized housing can be realized.

[0052] (Specific example of thickness) The thickness of the base film 21 is preferably 1.4 times or more and 3.0 times or less than that of the inner plating film 24. This allows both conductivity with the internal electrode layer 10 and mountability in a miniaturized housing to be achieved.

[0053] If the thickness of the base film 21 in the stacking direction is 1.4 times or less than that of the inner plating film 24, the conductive performance with the internal electrode layer 10 cannot be sufficiently ensured, and if it is 3.0 times or more, the overall thickness of the external electrode 20 becomes too large, hindering its mountability in a miniaturized housing.

[0054] The thickness of the base film 21 is preferably 1.4 to 3.0 times that of the outer plating film 25. By making the thickness 1.4 to 3.0 times, both conductivity with the internal electrode layer 10 and mountability in a miniaturized housing can be achieved.

[0055] If the thickness of the base film 21 is 1.4 times or less than that of the outer plating film 25, the conductive performance with the internal electrode layer 10 cannot be sufficiently ensured, and if it is 3.0 times or more, the overall thickness of the external electrode 20 becomes too large, hindering its mountability in a miniaturized housing.

[0056] The thickness of the base film 21 is preferably 0.4 to 0.6 times the total thickness of the inner plating film 24 and the outer plating film 25 .

[0057] By setting the ratio to 0.4 times or more and 0.6 times or less, it is possible to achieve both electrical conductivity with the internal electrode layer 10 and mountability in a miniaturized housing.

[0058] If it is less than 0.4 times, the electrical conductivity with the internal electrode layer 10 cannot be sufficiently ensured, and if it is more than 0.6 times, the thickness of the entire external electrode 20 becomes too large, hindering mountability in a miniaturized housing.

[0059] The thickness of the inner plating film 24 is preferably 0.2 to 0.3 times the total thickness of the base film 21 , the inner plating film 24 and the outer plating film 25 .

[0060] By setting the ratio to 0.2 times or more and 0.3 times or less, it is possible to achieve both solder erosion resistance and mountability in a miniaturized housing.

[0061] If it is less than 0.2 times, it is not possible to sufficiently prevent the solder from eroding the base film 21, and if it is more than 0.3 times, the thickness of the entire external electrode 20 becomes too large, hindering its mountability in a miniaturized housing.

[0062] The thickness of the outer plating film 25 is preferably 0.2 to 0.3 times the total thickness of the base film 21, the inner plating film 24 and the outer plating film 25.

[0063] By setting the ratio to 0.2 times or more and 0.3 times or less, it is possible to achieve both solder wettability with the inner plating film 24 and mountability in a miniaturized housing.

[0064] If it is less than 0.2 times, the solder will not wet up sufficiently onto the inner plating film 24, and if it is more than 0.3 times, the overall thickness of the external electrode 20 will become too large, hindering its mountability in a miniaturized housing.

[0065] (Claim 2) The thickness of the base film 21 is preferably 1.0 μm or more and 6.0 μm or less. By setting the thickness to 1.0 μm or more and 6.0 μm or less, it is possible to achieve both conductivity with the internal electrode layer 10 and mountability in a miniaturized housing.

[0066] If the thickness of the base film 21 is 1.0 μm or less, the conductive performance with the internal electrode layer 10 cannot be sufficiently ensured, and if it is 6.0 μm or more, the overall thickness of the external electrode 20 becomes too large, which hinders the mountability in a miniaturized housing.

[0067] The thickness of the inner plating film 24 is preferably 0.7 μm or more and 2.0 μm or less. By setting the thickness to 0.7 μm or more and 2.0 μm or less, it is possible to achieve both solder erosion resistance and mountability in a miniaturized housing.

[0068] If the thickness of the inner plating film 24 is 0.7 μm or less, it is not possible to sufficiently prevent solder erosion of the base film 21, and if it is 6.0% or more, the overall thickness of the external electrode 20 becomes too large, hindering its mountability in a miniaturized housing.

[0069] The thickness of the outer plating film 25 is preferably 0.7 μm or more and 2.0 μm or less. By setting the thickness to 0.7 μm or more and 2.0 μm or less, it is possible to achieve both solder wettability to the inner plating film 24 and mountability in a miniaturized housing.

[0070] If the thickness of the outer plating film 25 is 0.7 μm or less, the solder wettability to the inner plating film 24 cannot be sufficiently ensured, and if it is 6.0% or more, the overall thickness of the external electrode 20 becomes too large, which hinders the mountability in a miniaturized housing.

[0071] The total thickness of the base film 21, the inner plating film 24 and the outer plating film 25 is preferably 2.4 μm or more and 10 μm or less.

[0072] By making the thickness 2.4 μm or more and 10 μm or less, it is possible to achieve conductivity to the base film 21 and the internal electrode layer 10, solder wettability to the inner plating film 24, and prevention of solder erosion, while also achieving mountability in a miniaturized housing.

[0073] If the thickness is less than 2.4 μm, it is not possible to ensure conductivity between the base film 21 and the internal electrode layer 10, and it is not possible to prevent solder wettability and solder erosion of the inner plating film 24. If the thickness is more than 10 μm, it hinders mountability in a miniaturized housing.

[0074] In the multilayer ceramic component 1 of the present invention, the thickness of the external electrodes 20 in the stacking direction on the first and second main surfaces, the thickness of the external electrodes 20 in the longitudinal direction on the first end faces and second end faces, and the thickness of the external electrodes 20 in the width direction on the first and second side faces are small, making it possible to realize a multilayer ceramic capacitor that is compatible with a miniaturized housing.

[0075] (Size of Multilayer Ceramic Component) The size of the multilayer ceramic component 1 is not particularly limited. The size of the multilayer ceramic component 1 can be, for example, as follows. The dimension in the length direction L of the multilayer ceramic component 1 including the multilayer body 2 and the external electrodes 20 is defined as the L dimension. The L dimension is preferably 0.25 mm or more and 1.0 mm or less. The dimension in the stacking direction T of the multilayer ceramic component 1 including the multilayer body 2 and the external electrodes 20 is defined as the T dimension. The T dimension is preferably 0.125 mm or more and 0.5 mm or less. The dimension in the width direction W of the multilayer ceramic component 1 including the multilayer body 2 and the external electrodes 20 is defined as the W dimension. The W dimension is preferably 0.125 mm or more and 0.5 mm or less. The lengths of each portion of the multilayer body 2 and the external electrodes 20 can be measured using a micrometer or an optical microscope.

[0076] In addition, in the present embodiment, the multilayer ceramic component 1 has been described as a two-terminal multilayer ceramic capacitor by way of example, but the multilayer ceramic component 1 is not limited to being a two-terminal multilayer ceramic capacitor and may also be a multi-terminal multilayer ceramic capacitor having three or more terminals.

[0077] (Method of Measuring Thickness) The method of measuring thickness will be described. The measurement positions are as follows. The thickness of the first external electrode 20a and each layer included in the first external electrode 20a on the first principal surface 3a is the thickness of the thickest part on the first principal surface 3a. Similarly, the thickness of the second external electrode 20b and each layer included in the second external electrode 20b on the second principal surface 3b is the thickness of the thickest part on the second principal surface 3b.

[0078] The thickness of the external electrode 20 on the side surface 4 is the thickness of the thickest part on the side surface 4. Similarly, the thickness of the external electrode 20 on the end surface 5 is the thickness of the thickest part on the end surface 5.

[0079] These thicknesses are measured on the LT cross section at the center in the width direction W. The thickness can be measured using a scanning electron microscope (hereinafter referred to as SEM) after exposing the measurement target area by polishing the cross section.

[0080] (Method for Manufacturing Multilayer Ceramic Component) Next, a method for manufacturing a multilayer ceramic component will be described using the multilayer ceramic component 1 as an example.

[0081] (Fabrication of Laminated Block) A ceramic sheet and a conductive paste for the internal electrode layers are prepared. The ceramic sheet and the conductive paste for the internal electrode layers contain a binder and a solvent. Known organic binders and organic solvents can be used as the binder and solvent. The conductive paste for the internal electrode layers is printed in a predetermined pattern on the ceramic sheet by, for example, screen printing or gravure printing, to form the pattern of the internal electrode layer 10. A predetermined number of ceramic sheets for the outer layer portion on which the pattern of the internal electrode layer 10 is not printed are stacked, and then ceramic sheets on which the pattern of the internal electrode layer 10 is printed are stacked in sequence on top of these, and then a predetermined number of ceramic sheets for the other outer layer portion are stacked on top of these to fabricate a laminated sheet. The laminated sheets are pressed in the stacking direction using means such as a hydrostatic press to fabricate a laminated block.

[0082] (Production of laminated chip) The laminated block is cut to a predetermined size to cut out laminated chips. At this time, corners and ridges of the laminated chips may be rounded by barrel polishing or the like. The laminated chips are fired to become the laminate 2.

[0083] (Firing) Next, the laminated chip is fired to produce the laminate 2. The firing temperature depends on the materials of the dielectric layers 7 and the internal electrode layers 10, but is preferably 900°C or higher and 1400°C or lower.

[0084] (External Electrode) Next, the formation of the external electrode 20 will be described. (Base Film) A conductive paste that will become the base film 21 is applied to the two end faces 5 of the laminate 2 to form the base film 21. To form a baked layer, a conductive paste containing a glass component and a metal is applied by a method such as dipping, and then a baking process is performed to form the base film 21. The baking temperature at this time is preferably 500°C or higher and 900°C or lower. The baking time at this time is preferably 30 minutes or higher and 2 hours or lower. The baking atmosphere at this time is, for example, H ２ O and H ２ Preferably, the atmosphere is a reducing atmosphere containing

[0085] Next, a plating film is formed on the surface of the base film 21. In this embodiment, a Ni plating film is formed on the baked layer. This Ni plating film becomes the inner plating film 24. Next, a Sn plating film is formed on the Ni plating film. This Sn plating film becomes the outer plating film 25. The Ni plating film and the Sn plating film are formed sequentially by, for example, barrel plating. In this manner, the multilayer ceramic component 1 is obtained.

[0086] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various changes and modifications are possible.

[0087] REFERENCE SIGNS LIST 1 Multilayer ceramic component 2 Laminate 3 Main surface 4 Side surface 5 End surface 7 Dielectric layer 10 Internal electrode layer 11 Counter electrode portion 12 Lead electrode portion 20 External electrode 21 Undercoat film 24 Internal plating film (Ni plating film, plating film covering undercoat film) 25 External plating film (Sn plating film) 27 End surface external electrode 28 Main surface external electrode 29 Side surface external electrode 31 First main surface undercoat film 34 First main surface internal plating film 35 First main surface external plating film 41 Second main surface undercoat film 44 Second main surface internal plating film 45 Second main surface external plating film 51 First end surface undercoat film 54 First end surface internal plating film 55 First end surface external plating film 61 Second end surface undercoat film 64 Second end surface internal plating film 65 Second end surface external plating film 71 First side surface undercoat film 74 First side surface inner plating film 75 First side surface outer plating film 81 Second side surface undercoat film 84 Second side surface inner plating film 85 Second side surface outer plating film 90 Substrate 92 Sealing material T Stacking direction L Length direction W Width direction

Claims

1. A laminate including a plurality of laminated dielectric layers and a plurality of internal electrode layers, the laminate having a first main surface and a second main surface opposed to each other in the lamination direction, a first side surface and a second side surface opposed to each other in a width direction perpendicular to the lamination direction, and a first end surface and a second end surface opposed to each other in a length direction perpendicular to the lamination direction and the width direction; and external electrodes provided on the first end surface and the second end surface and connected to the internal electrode layers, the external electrodes extending to the first main surface and the second main surface, the external electrodes having an undercoat film in contact with the internal electrode layers, an inner plating film in contact with the undercoat film, and an outer plating film in contact with the inner plating film, the thickness of the undercoat film being greater than that of the inner plating film and the outer plating film, the thickness of the undercoat film being 1.4 to 3.0 times the thickness of the inner plating film, and the thickness of the undercoat film being 1.4 to 3.0 times the thickness of the outer plating film, A laminated ceramic component, wherein the thickness of the base film is 0.4 to 0.6 times the total thickness of the base film, the inner plating film, and the outer plating film, the thickness of the inner plating film is 0.2 to 0.3 times the total thickness of the base film, the inner plating film, and the outer plating film, and the thickness of the outer plating film is 0.2 to 0.3 times the total thickness of the base film, the inner plating film, and the outer plating film.

2. A multilayer ceramic component as described in claim 1, wherein the thickness of the base film is 1 μm or more and 6 μm or less, the thickness of the inner plating film is 0.7 μm or more and 2 μm or less, the thickness of the outer plating film is 0.7 μm or more and 2 μm or less, and the total thickness of the base film, the inner plating film, and the outer plating film is 2.4 μm or more and 10 μm or less.