Multilayer ceramic capacitor

Abstract

Provided is a laminated ceramic capacitor whereby cracking or the like is less likely to occur in a ceramic body. Provided is a laminated ceramic capacitor comprising: a ceramic body, in which a plurality of ceramic layers, a plurality of first internal electrodes, and a plurality of second internal electrodes are laminated in the height direction, and which has a first principal surface and a second principal surface that face one another in the height direction, a first end surface and a second end surface that face one another in the length direction orthogonal to the height direction, and a first side surface and a second side surface that face one another in the width direction orthogonal to the height direction and to the length direction; and a first external electrode and a second external electrode that are formed on an outer surface of the ceramic body. The first internal electrodes are drawn out to the first end surface and electrically connected with the first external electrode; and the second internal electrodes are drawn out to the second end surface and electrically connected with the second external electrode. When a cross-section parallel to the first side surface and the second side surface is viewed, the first external electrode is formed in an L-shape on the first end surface and the first principal surface, and the second external electrode is formed in an L-shape on the second end surface and the first principal surface; and an R-dimension of a ridge line where the first principal surface and the first end surface, the first side surface, the second end surface, and the second side surface are in contact is greater than an R-dimension of a ridge line where the second principal surface and the first end surface, the first side surface, the second end surface, and the second side surface are in contact.

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic capacitor.

Background Art

[0002] Multilayer ceramic capacitors are widely used in various devices including electronic devices and electrical devices (hereinafter referred to as "electronic devices, etc."). For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-100647) discloses a multilayer ceramic capacitor having a typical structure.

[0003] Recently, miniaturization and high functionality of electronic devices, etc. have been rapidly progressing. Due to the miniaturization of electronic devices, etc., the internal volume (space volume) of electronic devices, etc. that houses electronic circuits composed of electronic components has become extremely small. In addition, due to the high functionality of electronic devices, etc., the number of electronic components required to form an electronic circuit has been rapidly increasing.

[0004] Therefore, along with the miniaturization and high functionality of electronic devices, etc., miniaturization is also required for the electronic components that make up the electronic circuit. For example, in the case of multilayer ceramic capacitors, products with an extremely thin ceramic body having a thickness of several tens of μm have been put into practical use.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, along with the miniaturization and high functionality of electronic devices, etc., miniaturization, particularly thinning, of electronic components is required. However, in the case of multilayer ceramic capacitors, with thinning, a decrease in mechanical strength against external forces has become a problem.

[0007] On the other hand, multilayer ceramic capacitors are often mounted on substrates or materials equivalent to substrates (hereinafter, both will be collectively referred to as "substrates") by, for example, the reflow soldering process shown below.

[0008] First, a circuit board is prepared for mounting. Electrodes are formed on the main surface of the circuit board, and solder paste is pre-applied to the surface of the electrodes. Next, a mounting device equipped with a nozzle is prepared. The nozzle is used to adsorb the top surface (second main surface) of the multilayer ceramic capacitor, and then the nozzle is moved to place the bottom surface (first main surface) of the multilayer ceramic capacitor onto the pair of electrodes on the circuit board that have solder paste applied to them. Next, the circuit board on which the multilayer ceramic capacitor is placed is heated to melt the solder paste, and then the entire circuit board is cooled to solidify the solder paste again, thereby mounting the multilayer ceramic capacitor onto the electrodes on the circuit board.

[0009] In this reflow soldering process, when a multilayer ceramic capacitor is placed on the electrodes of the substrate using a nozzle, the ridge, which is the outer edge of the bottom surface (first main surface) of the ceramic element, collides with the substrate or the electrodes formed on the substrate, causing cracks or other damage (hereinafter, "cracks, fractures, chips, etc." are collectively referred to as "cracks, etc.") to occur in the ceramic element. In particular, in multilayer ceramic capacitors that have been made thinner and have reduced mechanical strength against external forces, cracks in the ceramic element that occur during mounting are an extremely serious problem.

[0010] Therefore, the present invention aims to provide a multilayer ceramic capacitor in which cracks are less likely to occur in the ceramic body even if the ridge line, which is the outer edge of the bottom surface (first main surface) of the ceramic body, collides with a substrate or electrodes formed on the substrate, for example, during mounting. [Means for solving the problem]

[0011] To solve the conventional problems described above, a multilayer ceramic capacitor according to one embodiment of the present invention comprises a ceramic body having a plurality of ceramic layers, a plurality of first internal electrodes, and a plurality of second internal electrodes stacked in the height direction, having a first main surface and a second main surface facing each other in the height direction, a first end surface and a second end surface facing each other in the length direction perpendicular to the height direction, and a first side surface and a second side surface facing each other in the width direction perpendicular to the height direction and the length direction, and a first external electrode and a second external electrode formed on the outer surface of the ceramic body, wherein the first internal electrode is drawn to the first end surface A multilayer ceramic capacitor in which a first external electrode is brought out and electrically connected to a first external electrode, and a second internal electrode is brought out to a second end face and electrically connected to a second external electrode, wherein when viewed in a cross section parallel to the first side surface and the second side surface, the first external electrode is formed in an L-shape on the first end face and the first main surface, the second external electrode is formed in an L-shape on the second end face and the first main surface, and the radius R of the ridge where the first main surface is in contact with the first end face, first side surface, second end face, and second side surface is greater than the radius R of the ridge where the second main surface is in contact with the first end face, first side surface, second end face, and second side surface. [Effects of the Invention]

[0012] In one embodiment of the present invention, the multilayer ceramic capacitor has a large radius (R) at the edges where the first main surface (bottom surface; mounting surface) and the first end surface, first side surface, second end surface, and second side surface meet. Therefore, even if these edges collide with the substrate or electrodes formed on the substrate during mounting, cracks are less likely to occur in the ceramic body. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of a multilayer ceramic capacitor 100 according to the first embodiment, showing the multilayer ceramic capacitor 100 from the first main surface 1A side. [Figure 2] This is a perspective view of the multilayer ceramic capacitor 100, showing the multilayer ceramic capacitor 100 from the second main surface 1B side. [Figure 3]This is a cross-sectional view of the multilayer ceramic capacitor 100, showing the cross-section of the XX portion indicated by the dashed-dotted arrow in Figure 1(A). [Figure 4] This is a cross-sectional view of the main part of the multilayer ceramic capacitor 100. [Figure 5] Figures 5(A) to 5(D) are explanatory diagrams showing the steps in an example of a manufacturing method for a multilayer ceramic capacitor 100. [Figure 6] Figures 6(E) to 6(J) are a continuation of Figure 5(D) and are explanatory diagrams showing the steps in an example of a manufacturing method for a multilayer ceramic capacitor 100. [Figure 7] This is a cross-sectional view of a multilayer ceramic capacitor 200 according to a second embodiment. [Figure 8] Figures 8(A) to 8(D) are explanatory diagrams showing the steps in an example of a manufacturing method for a multilayer ceramic capacitor 200. [Figure 9] Figures 9(E) to 9(J) are a continuation of Figure 8(D) and are explanatory diagrams showing the steps in an example of a manufacturing method for a multilayer ceramic capacitor 200. [Modes for carrying out the invention]

[0014] The embodiments for carrying out the present invention will be described below with reference to the drawings.

[0015] Each embodiment is illustrative of an embodiment of the present invention, and the present invention is not limited to the contents of the embodiments. It is also possible to combine the contents described in different embodiments, and the contents of such implementations are also included in the present invention. Furthermore, the drawings are for the purpose of aiding the understanding of the specification and may be schematically drawn, and the proportions of the dimensions of the drawn components or the dimensions between components may not match the proportions of those dimensions described in the specification. In addition, components described in the specification may be omitted in the drawings, or their quantities may be omitted.

[0016] [First Embodiment] FIG. 1, FIG. 2, FIG. 3, and FIG. 4 each show a multilayer ceramic capacitor 100 according to the first embodiment. However, FIG. 1 is a perspective view of the multilayer ceramic capacitor 100, showing the multilayer ceramic capacitor 100 from the side of the first main surface 1A. FIG. 2 is also a perspective view of the multilayer ceramic capacitor 100, showing the multilayer ceramic capacitor 100 from the side of the second main surface 1B. FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor 100, showing the cross-section of the portion X-X indicated by the dashed-dotted arrow in FIG. 1(A). FIG. 4 is a cross-sectional view of the main part of the multilayer ceramic capacitor 100.

[0017] Note that the drawings show the height direction T, the length direction L, and the width direction W of the multilayer ceramic capacitor 100, and in the following description, reference may be made to these directions. In the present embodiment, the stacking direction of the ceramic layer 1a described later is the height direction T of the multilayer ceramic capacitor 100.

[0018] The multilayer ceramic capacitor 100 includes a ceramic body 1. The ceramic body 1 is in the shape of a rectangular parallelepiped and has a first main surface 1A and a second main surface 1B facing each other in the height direction T, a first end surface 1C and a second end surface 1D facing each other in the length direction L, and a first side surface 1E and a second side surface 1F facing each other in the width direction W.

[0019] The dimensions of the ceramic body 1 are arbitrary. For example, it is also preferable that one of the dimensions in the length direction L and the dimensions in the width direction W is 1.0 mm or less and the other is 0.5 mm or less. Also, it is preferable that the dimension in the height direction T is 0.1 mm or less. When the present invention is implemented, in the thus miniaturized and thinned multilayer ceramic capacitor 100, as will be described later, since the R dimension of the ridge line where the first main surface 1A, which is the mounting surface, contacts the first end surface 1C, the first side surface 1E, the second end surface 1D, and the second side surface 1F is large, when mounting, even if these ridge lines cause the first main surface of the ceramic body to collide with a substrate or an electrode formed on the substrate, the occurrence of cracks or the like in the ceramic body 1 is suppressed.

[0020] The ceramic body 1 consists of a ceramic layer 1a, a first internal electrode 2, a second internal electrode 3, and a dummy internal electrode 4, all of which are stacked. The ceramic layer 1a, the first internal electrode 2, the second internal electrode 3, and the dummy internal electrode 4 are stacked in the height direction T of the ceramic body 1.

[0021] Furthermore, as will be described later, the dummy internal electrode 4 is an electrode provided not primarily for forming capacitance, but as a base external electrode for the first external electrode 5 and the second external electrode 6.

[0022] The material of the ceramic element 1 (ceramic layer 1a) is arbitrary, but for example, a dielectric ceramic mainly composed of BaTiO3 can be used. However, instead of BaTiO3, dielectric ceramics mainly composed of other materials such as CaTiO3, SrTiO3, or CaZrO3 may be used.

[0023] The thickness of the ceramic layer 1a is arbitrary, but for example, in the effective region for capacitance formation where the first internal electrode 2 and the second internal electrode 3 are formed, it can be approximately 0.3 μm to 2.0 μm.

[0024] The number of ceramic layers 1a is arbitrary, but for example, in the effective region for capacitance formation where the first internal electrode 2 and the second internal electrode 3 are formed, it can be approximately 1 to 6000 layers.

[0025] On both the upper and lower sides of the ceramic body 1, a protective layer (outer layer) is provided, consisting only of a ceramic layer 1a, without the first internal electrode 2 and the second internal electrode 3 being formed. However, in this embodiment, a dummy internal electrode 4 is formed on the protective layer. The thickness of the protective layer is arbitrary, but can be, for example, about 5 μm to 150 μm. The thickness of the ceramic layer 1a of the protective layer may be greater than the thickness of the ceramic layer 1a in the effective region of capacitance formation where the first internal electrode 2 and the second internal electrode 3 are formed. Furthermore, the material of the ceramic layer 1a of the protective layer may be different from the material of the ceramic layer 1a in the effective region.

[0026] As can be seen in Figure 3, the first internal electrode 2 extends in the longitudinal direction L of the ceramic body 1, with one end drawn out to the first end face 1C of the ceramic body 1. The second internal electrode 3 extends in the longitudinal direction L of the ceramic body 1, with one end drawn out to the second end face 1D of the ceramic body 1. In principle, it is preferable that the first internal electrode 2 and the second internal electrode 3 are stacked alternately.

[0027] The dummy internal electrode 4, provided as a base external electrode for the first external electrode 5 and the second external electrode 6, has a smaller length L dimension than the first internal electrode 2 and the second internal electrode 3. One end of the dummy internal electrode 4 is drawn out to either the first end face 1C or the second end face 1D of the ceramic body 1. Furthermore, the dummy internal electrode 4 positioned closest to the first main surface 1A of the ceramic body 1 is exposed to the first main surface 1A of the ceramic body 1.

[0028] Furthermore, the dummy internal electrode 4 is positioned at least one layer on the first main surface 1A side of the ceramic body 1, in the case of the first external electrode 5 and the second external electrode 6, and exposed on the first main surface of the ceramic body 1.

[0029] The main component (metal component) of the first internal electrode 2, the second internal electrode 3, and the dummy internal electrode 4 can be any material, but in this embodiment, Ni was used. However, other metals such as Cu, Ag, Pd, and Au may be used instead of Ni. Also, Ni, Cu, Ag, Pd, and Au may be alloys with other metals. The first internal electrode 2, the second internal electrode 3, and the dummy internal electrode 4 may contain other components such as ceramics in addition to the metal component.

[0030] The thicknesses of the first internal electrode 2, the second internal electrode 3, and the dummy internal electrode 4 are arbitrary, but can be, for example, about 0.3 μm to 1.5 μm.

[0031] A first external electrode 5 and a second external electrode 6 are formed on the outer surface of the ceramic body 1. When viewed in a cross-section parallel to the first side surface 1E and the second side surface 1F, the first external electrode 5 is formed in an L-shape on the first end surface 1C and the first main surface 1A, and the second external electrode 6 is formed in an L-shape on the second end surface 1D and the first main surface 1A. The first external electrode 5 is electrically connected to the first internal electrode 2 at the first end surface 1C. The second external electrode 6 is electrically connected to the second internal electrode 3 at the second end surface 1D.

[0032] The first external electrode 5 and the second external electrode 6 have the same multilayer structure. In this embodiment, the first external electrode 5 and the second external electrode 6 are comprised, from bottom to top, a base external electrode, a Cu-plated external electrode layer 7 formed on the outside of the base external electrode, a Ni-plated external electrode layer 8 formed on the outside of the Cu-plated external electrode layer 7, and an Au-plated external electrode layer 9 formed on the outside of the Ni-plated external electrode layer 8. However, the structure and materials of the first external electrode 5 and the second external electrode 6 are arbitrary and not limited to these structures and materials. Also, the dimensions such as the thickness, width, and length of the first external electrode 5 and the second external electrode 6 are arbitrary and can be freely set. In particular, various variations can be adopted regarding the number of layers, material, and dimensions of the plated external electrode layers.

[0033] Next, we will explain the base external electrodes for the first external electrode 5 and the second external electrode 6. A base external electrode is an electrode that serves as the base when forming the plated external electrode layer on its outside.

[0034] The base external electrode of the first external electrode 5 is composed of the ends of the first internal electrode 2 and dummy internal electrode 4 that are drawn out to the first end face 1C, and the main surface of the dummy internal electrode 4 that is exposed to the first main surface 1A. Figure 3 illustrates a structure in which the first external electrode 5 has four layers of dummy internal electrodes 4 as the base external electrode, with the upper main surface of the dummy internal electrode 4 located closest to the first main surface 1A being exposed to the first main surface 1A, and the ends of the remaining three layers of dummy internal electrodes 4 being drawn out to the first end face 1C. However, the number of layers of the dummy internal electrode 4 of the first external electrode 5 is arbitrary, and it is sufficient to have at least one layer located closest to the first main surface 1A of the ceramic body 1, with its upper main surface exposed to the outside from the first main surface 1A of the ceramic body 1.

[0035] Similarly, the base external electrode of the second external electrode 6 is composed of the ends of the second internal electrode 3 and dummy internal electrode 4 that are drawn out to the second end face 1D, and the main surface of the dummy internal electrode 4 that is exposed to the first main surface 1A. Figures 3 and 4 illustrate a structure in which the second external electrode 6 has four layers of dummy internal electrodes 4 as the base external electrode, with the upper main surface of the dummy internal electrode 4 located closest to the first main surface 1A being exposed to the first main surface 1A, and the ends of the remaining three layers of dummy internal electrodes 4 being drawn out to the second end face 1D. However, the number of layers of the dummy internal electrode 4 of the second external electrode 6 is arbitrary, and it is sufficient to have at least one layer located closest to the first main surface 1A of the ceramic body 1, with its upper main surface exposed to the outside from the first main surface 1A of the ceramic body 1.

[0036] As described above, the ends of the first internal electrode 2 drawn out to the first end face 1C of the ceramic body 1, and the ends of the second internal electrode 3 drawn out to the second end face 1D of the ceramic body 1, are also part of the base external electrodes of the first external electrode 5 and the second external electrode 6. In Figures 3 and 4, to avoid making the drawings too complex, the ends of the first internal electrode 2 and the ends of the second internal electrode 3 are not shown as parts of the first external electrode 5 and the second external electrode 6 (the leader lines from the reference numeral "5" indicating the first external electrode 5 and the reference numeral "6" indicating the second external electrode 6 in the figures have been omitted).

[0037] The base external electrodes of the first external electrode 5 and the second external electrode 6 function as a base for forming the Cu plated external electrode layer 7 on their outside. As described above, in this embodiment, the ends of the first internal electrode 2 and the dummy internal electrode 4 drawn out to the first end face 1C, the ends of the second internal electrode 3 and the dummy internal electrode 4 drawn out to the second end face 1D are also part of the base external electrodes of the first external electrode 5 and the second external electrode 6. On the first end face 1C, the ends of multiple linear first internal electrodes 2 and the ends of the dummy internal electrode 4, which extend in the width direction W, are exposed at intervals (with the ends of linear ceramic layers 1a, which extend in the width direction W, in between). On the second end face 1D, the ends of multiple linear second internal electrodes 3 and the ends of the dummy internal electrode 4, which extend in the width direction W, are exposed at intervals. However, even though the ends of the first internal electrodes 2, the second internal electrodes 3, and the dummy internal electrode 4 are spaced apart, they function as a base layer when forming the plated external electrode layer.

[0038] The first external electrode 5 and the second external electrode 6 are provided with a Cu-plated external electrode layer 7 on the outside of the underlying external electrode. The Cu-plated external electrode layer 7 primarily serves to improve moisture resistance. It is also preferable that the Cu-plated external electrode layer 7 contains Ni. In this case, dissolution of the external electrode layer into the solder can be suppressed.

[0039] The first external electrode 5 and the second external electrode 6 are provided with a Ni-plated external electrode layer 8 on the outside of the Cu-plated external electrode layer 7. The Ni-plated external electrode layer 8 primarily serves to improve solder heat resistance and bonding properties. It is also preferable that the Ni-plated external electrode layer 8 contains phosphorus (P). In this case, the mechanical strength of the external electrode layer can be improved.

[0040] The first external electrode 5 and the second external electrode 6 are provided with an Au-plated external electrode layer 9 on the outside of the Ni-plated external electrode layer 8. The Au-plated external electrode layer 9 primarily serves to improve the wettability of the external electrode layer to solder.

[0041] As can be seen from Figures 1 and 2, in the multilayer ceramic capacitor 100 of this embodiment, the radius R of each of the following ridges is larger than the radius R of each of the following ridges: E11 where the first main surface 1A and the first end surface 1C meet, E12 where the first main surface 1A and the first side surface 1E meet, E13 where the first main surface 1A and the second end surface 1D meet, and E14 where the first main surface 1A and the second side surface 1F meet.

[0042] In this embodiment, the manufacturing process includes a separate step to increase the R dimension for the ridge line E11 where the first main surface 1A and the first end surface 1C meet, the ridge line E12 where the first main surface 1A and the first side surface 1E meet, the ridge line E13 where the first main surface 1A and the second end surface 1D meet, and the ridge line E14 where the first main surface 1A and the second side surface 1F meet. On the other hand, the manufacturing process does not include a step to increase the R dimension for the ridge line E21 where the second main surface 1B and the first end surface 1C meet, the ridge line E22 where the second main surface 1B and the first side surface 1E meet, the ridge line E23 where the second main surface 1B and the second end surface 1D meet, and the ridge line E24 where the second main surface 1B and the second side surface 1F meet.

[0043] In the multilayer ceramic capacitor 100, the first main surface 1A of the ceramic body 1, which is equipped with a first external electrode 5 and a second external electrode 6, is the mounting surface for the substrate (as mentioned above, "substrate" includes "something equivalent to a substrate"). The multilayer ceramic capacitor 100 has large radius (large curvature) edges where the first main surface 1A and the first end surface 1C meet, the first main surface 1A and the first side surface 1E meet, the first main surface 1A and the second end surface 1D meet, and the first main surface 1A and the second side surface 1F meet. Therefore, when the multilayer ceramic capacitor 100 is placed on a substrate for mounting, even if these edges collide with the substrate or electrodes formed on the substrate, the impact is mitigated, thus suppressing the occurrence of cracks in the ceramic body 1.

[0044] Furthermore, the radius (R) dimensions of the ridges E11 where the first main surface 1A and the first end surface 1C meet, E12 where the first main surface 1A and the first side surface 1E meet, E13 where the first main surface 1A and the second end surface 1D meet, and E14 where the first main surface 1A and the second side surface 1F meet are preferably, for example, between 1 μm and 10 μm. This is because if the radius is less than 1 μm, the effect of suppressing the occurrence of cracks in the ceramic body 1 is small. Also, if it exceeds 10 μm, the process of increasing the radius of each of these ridges takes time, which reduces the productivity of multilayer ceramic capacitors. On the other hand, the radius (R) dimensions of the ridges E21 where the second main surface 1B and the first end surface 1C meet, E22 where the second main surface 1B and the first side surface 1E meet, E23 where the second main surface 1B and the second end surface 1D meet, and E24 where the second main surface 1B and the second side surface 1F meet are preferably less than 1 μm. This is because, in this case, there is no need to provide a separate process for increasing the radius of each of these ridges.

[0045] Furthermore, as can be seen from Figures 1 and 2, the multilayer ceramic capacitor 100 of this embodiment has the following corners: corner C11 where the first main surface 1A, the first end surface 1C, and the first side surface 1E meet; corner C12 where the first main surface 1A, the first side surface 1E, and the second end surface 1D meet; corner C13 where the first main surface 1A, the second end surface 1D, and the second side surface 1F meet; and the first main surface 1A, the second side surface 1F, and the first end surface The radius (R) of corner C14, where 1C is in contact, is greater than the radius (R) of corner C21, where the second main surface 1B, the first end surface 1C, and the first side surface 1E are in contact; corner C22, where the second main surface 1B, the first side surface 1E, and the second end surface 1D are in contact; corner C23, where the second main surface 1B, the second end surface 1D, and the second side surface 1F are in contact; and corner C24, where the second main surface 1B, the second side surface 1F, and the first end surface 1C are in contact. This is because the radius radius (R) of the edges E11 where the first main surface 1A and the first end surface 1C meet, the edge E12 where the first main surface 1A and the first side surface 1E meet, the edge E13 where the first main surface 1A and the second end surface 1D meet, and the edge E14 where the first main surface 1A and the second side surface 1F meet is larger than the radius radius (R) of the edges E21 where the second main surface 1B and the first end surface 1C meet, the edge E22 where the second main surface 1B and the first side surface 1E meet, the edge E23 where the second main surface 1B and the second end surface 1D meet, and the edge E24 where the second main surface 1B and the second side surface 1F meet. In other words, the angle at which two edges with large radius radius (R) intersect will have a larger radius (R) than the angle at which two edges with small radius radius (R) intersect.

[0046] Because the multilayer ceramic capacitor 100 has large radius (R) dimensions at the corners C11 where the first main surface 1A, the first end surface 1C, and the first side surface 1E meet, the corner C12 where the first main surface 1A, the first side surface 1E, and the second end surface 1D meet, the corner C13 where the first main surface 1A, the second end surface 1D, and the second side surface 1F meet, and the corner C14 where the first main surface 1A, the second side surface 1F, and the first end surface 1C meet, when the multilayer ceramic capacitor 100 is placed on a substrate or the like for mounting, even if these corners collide with the substrate or electrodes formed on the substrate, the impact is mitigated, thus suppressing the occurrence of cracks in the ceramic body 1.

[0047] In this embodiment, the multilayer ceramic capacitor 100 has a plurality of embossed holes 10 formed on the second main surface 1B of the ceramic body 1. In this embodiment, a plurality of embossed holes 10 of the same shape and dimensions are formed on the second main surface 1B of the ceramic body 1, aligned in the length direction L and the width direction W.

[0048] In this application, an embossed hole refers to a concave, bottomed hole. The concave surface may be hemispherical or non-hemispherical. The dimensions, number, arrangement, spacing, and area of ​​the embossed holes 10 are arbitrary and can be set as appropriate. The method of forming the embossed holes 10 is also arbitrary. Whether or not embossed holes 10 are formed on the second main surface 1B can be easily confirmed by comparing it with other surfaces of the ceramic body 1 (for example, the first main surface 1A).

[0049] In the multilayer ceramic capacitor 100, the second main surface 1B of the ceramic body 1 is the surface that is attracted by, for example, the nozzle of a mounting device during mounting, and is therefore susceptible to impact from the nozzle. In this embodiment, the multilayer ceramic capacitor 100 has multiple embossed holes 10 formed on the second main surface 1B of the ceramic body 1, so that even if an impact is applied by a nozzle or the like, it is resistant to impact and the occurrence of cracks in the ceramic body 1 is suppressed. The embossed holes 10 are fine, with a depth that fits within one to several tens of layers of ceramic layers 1a, and this can effectively improve the impact resistance of the ceramic body 1. However, if the depth of the embossed holes 10 becomes too large, it may conversely reduce the overall strength of the ceramic body 1, so it is necessary not to make the depth of the embossed holes 10 too large.

[0050] The multilayer ceramic capacitor 100 of this embodiment can be manufactured, for example, by the method shown in Figures 5(A) to 6(J).

[0051] First, a ceramic green sheet 11a is prepared for fabricating the ceramic layer 1a of the ceramic substrate 1, as shown in Figure 5(A). The ceramic green sheet 11a is prepared as a mother ceramic green sheet 50, in which numerous ceramic green sheets 11a are arranged in a matrix, in order to manufacture a large number of multilayer ceramic capacitors 100 at once.

[0052] Although not shown in the diagram, first, dielectric ceramic powder, binder resin, solvent, etc. are prepared, and these are wet-mixed to create a ceramic slurry.

[0053] Next, the ceramic slurry is applied to the carrier film in a sheet-like manner using a die coater, gravure coater, microgravure coater, etc., and dried to produce a mother ceramic green sheet 50.

[0054] Next, as also shown in Figure 5(A), conductive paste 12 for forming the first internal electrode 2, conductive paste 13 for forming the second internal electrode 3, and conductive paste 14 for forming the dummy internal electrode 4, which have been prepared in advance, are applied (e.g., printed) in a desired pattern shape to the main surface of a predetermined ceramic green sheet 11a in the mother ceramic green sheet 50. For the conductive paste, for example, a mixture of solvent, binder resin, metal powder (e.g., Ni powder) can be used.

[0055] Next, as shown in Figure 5(B), the mother ceramic green sheets 50 are stacked in a predetermined order and pressed together to produce a mother unfired ceramic body 60 in which a large number of unfired ceramic bodies 11 are arranged in a matrix.

[0056] Next, as shown in Figure 5(C), a jig 70 is prepared, having multiple protrusions 70a formed on its upper main surface. Subsequently, the lower main surface of the mother unfired ceramic body 60 is pressed against the protrusions 70a of the jig 70. As a result, as shown in Figure 4(D), multiple embossed holes 10 are formed on the second main surface 1B of each unfired ceramic body 11 of the mother unfired ceramic body 60.

[0057] Next, as shown in Figure 6(E), the mother unfired ceramic body 60 is cut into individual unfired ceramic bodies 11.

[0058] Next, the unfired ceramic body 11 is fired according to a predetermined profile to produce the ceramic body 1 shown in Figure 6(F). At this time, conductive paste 12 is fired simultaneously inside the ceramic body 1 to form the first internal electrode 2, conductive paste 13 is fired simultaneously to form the second internal electrode 3, and conductive paste 14 is fired simultaneously to form the dummy internal electrode 4.

[0059] Next, a jig 80 is prepared as shown in Figure 6(G). The second main surface 1B of the ceramic body 1 is then fixed to the upper main surface of the jig 80. Subsequently, for example, sandblasting is performed to remove the first main surface 1A of the ceramic body 1, exposing the upper main surface of the dummy internal electrode 4, which is located closest to the first main surface 1A of the ceramic body 1, to the first main surface 1A of the ceramic body 1.

[0060] At the same time, the edges E11 where the first main surface 1A and the first end surface 1C meet, the edges E12 where the first main surface 1A and the first side surface 1E meet, the edges E13 where the first main surface 1A and the second end surface 1D meet, and the edges E14 where the first main surface 1A and the second side surface 1F meet are each cut away, and the edges E11 where the first main surface 1A and the first end surface 1C meet, the edges E12 where the first main surface 1A and the first side surface 1E meet, and the first main surface The radius (R) of the ridge line E13 where 1A and the second end face 1D meet, and the radius (R) of the ridge line E14 where the first main face 1A and the second side face 1F meet, are larger (more rounded) than the radius (R) of the ridge line E21 where the second main face 1B and the first end face 1C meet, the ridge line E22 where the second main face 1B and the first side face 1E meet, the ridge line E23 where the second main face 1B and the second end face 1D meet, and the ridge line E24 where the second main face 1B and the second side face 1F meet.

[0061] Next, as shown in Figure 6(H), the ends of the first internal electrode 2, the second internal electrode 3, and the dummy internal electrode 4, which are drawn out to the first end face 1C and the second end face 1D, and the upper main surface of the dummy internal electrode 4 exposed on the first main surface 1A are used as the base external electrodes. After applying a predetermined catalyst to the surface of these base external electrodes as needed, electroless plating is performed to form a Cu plated external electrode layer 7.

[0062] Next, as shown in Figure 6(I), a predetermined catalyst is applied to the outside of the Cu-plated outer electrode layer 7 as needed, and then electroless plating is performed to form the Ni-plated outer electrode layer 8.

[0063] Next, as shown in Figure 6(J), an electroless plating process is performed on the outside of the Ni-plated external electrode layer 8, after applying a predetermined catalyst as needed, to form the Au-plated external electrode layer 9. As a result, the first external electrode 5 is formed in an L-shape on the first end face 1C and the first main surface 1A of the ceramic body 1, and the second external electrode 6 is formed in an L-shape on the second end face 1D and the first main surface 1A of the ceramic body 1, completing the multilayer ceramic capacitor 100 according to the first embodiment.

[0064] [Second Embodiment] Figure 7 shows a multilayer ceramic capacitor 200 according to the second embodiment. However, Figure 7 is a cross-sectional view of the multilayer ceramic capacitor 200.

[0065] The multilayer ceramic capacitor 200 according to the second embodiment has some modifications to the configuration of the multilayer ceramic capacitor 100 according to the first embodiment described above.

[0066] Specifically, in the multilayer ceramic capacitor 100, a dummy internal electrode 4 was used as part of the base external electrode for the first external electrode 5 and the second external electrode 6. The multilayer ceramic capacitor 200 changed this and omitted the dummy internal electrode 4. Instead, the multilayer ceramic capacitor 200 formed a NiCr thin film layer 27 by sputtering as the base external electrode for the first external electrode 25 and the second external electrode 26. The NiCr thin film layer 27 has high adhesion to the ceramic body 1 and makes an excellent base external electrode for the first external electrode 25 and the second external electrode 26.

[0067] Furthermore, in the multilayer ceramic capacitor 100, the first external electrode 5 and the second external electrode 6 were plated external electrode layers consisting of a Cu plated external electrode layer 7, a Ni plated external electrode layer 8, and an Au plated external electrode layer 9 in that order on the outside of the underlying external electrode. The multilayer ceramic capacitor 200 modified this by forming a Ni plated external electrode layer 28 and an Au plated external electrode layer 29 in that order on the outside of the underlying external electrode, which is the NiCr thin film layer 27, as the plated external electrode layers for the first external electrode 25 and the second external electrode 26.

[0068] The other configurations of the multilayer ceramic capacitor 200 were the same as those of the multilayer ceramic capacitor 100.

[0069] Similar to the multilayer ceramic capacitor 100, the radius R of the ridge line E11 where the first main surface 1A and the first end surface 1C meet, the radius R12 where the first main surface 1A and the first side surface 1E meet, the radius R13 where the first main surface 1A and the second end surface 1D meet, and the radius R14 where the first main surface 1A and the second side surface 1F meet is larger than the radius R of the ridge line E21 where the second main surface 1B and the first end surface 1C meet, the radius R22 where the second main surface 1B and the first side surface 1E meet, the radius R23 where the second main surface 1B and the second end surface 1D meet, and the radius R24 where the second main surface 1B and the second side surface 1F meet. Therefore, when the multilayer ceramic capacitor 200 is placed on a substrate or the like for mounting, even if these edges collide with the substrate or electrodes formed on the substrate, the impact is mitigated, thus suppressing the occurrence of cracks or other damage in the ceramic body 1.

[0070] The multilayer ceramic capacitor 200 of this embodiment can be manufactured, for example, by the method shown in Figures 8(A) to 9(J).

[0071] First, a ceramic green sheet 11a is prepared for fabricating the ceramic layer 1a of the ceramic substrate 1, as shown in Figure 8(A). The ceramic green sheet 11a is prepared as a mother ceramic green sheet 50 for the batch manufacturing of a large number of multilayer ceramic capacitors 100.

[0072] Next, as shown in Figure 8(A), the conductive paste 12 for forming the first internal electrode 2 and the conductive paste 13 for forming the second internal electrode 3, which have been prepared in advance, are applied to the main surface of a predetermined ceramic green sheet 11a in the mother ceramic green sheet 50 in the desired pattern shape. Note that since the multilayer ceramic capacitor 200 does not have dummy internal electrodes, conductive paste for forming dummy internal electrodes is not applied.

[0073] Next, as shown in Figure 8(B), the mother ceramic green sheets 50 are stacked in a predetermined order and pressed together to produce the mother unfired ceramic body 60.

[0074] Next, as shown in Figure 8(C), the lower main surface of the unfired ceramic mother body 60 is pressed against a jig 70 having multiple protrusions 70a formed on its upper main surface, and as shown in Figure 8(D), multiple embossed holes 10 are formed on the second main surface 1B of each unfired ceramic body 11.

[0075] Next, as shown in Figure 9(E), the mother unfired ceramic body 60 is cut into individual unfired ceramic bodies 11.

[0076] Next, the unfired ceramic body 11 is fired according to a predetermined profile to produce the ceramic body 1 shown in Figure 9(F).

[0077] Next, a jig 80 is prepared as shown in Figure 9(G). The second main surface 1B of the ceramic body 1 is then fixed to the upper main surface of the jig 80. Subsequently, for example, sandblasting is performed to remove the edges E11 where the first main surface 1A and the first end surface 1C meet, the edges E12 where the first main surface 1A and the first side surface 1E meet, the edges E13 where the first main surface 1A and the second end surface 1D meet, and the edges E14 where the first main surface 1A and the second side surface 1F meet, thereby increasing the radius (R) of these edges.

[0078] Next, as shown in Figure 9(H), a NiCr thin film layer 27 is formed by sputtering as the base external electrode for the first external electrode 25 and the second external electrode 26.

[0079] Next, as shown in Figure 9(I), a predetermined catalyst is applied to the outside of the NiCr thin film layer 27, which is the base external electrode for the first external electrode 25 and the second external electrode 26, as needed, and then electroless plating is performed to form a Ni plated external electrode layer 28.

[0080] Next, as shown in Figure 9(J), an electroless plating process is performed on the outside of the Ni-plated external electrode layer 28, after applying a predetermined catalyst as needed, to form the Au-plated external electrode layer 29. As a result, the first external electrode 25 is formed in an L-shape on the first end face 1C and the first main surface 1A of the ceramic body 1, and the second external electrode 26 is formed in an L-shape on the second end face 1D and the first main surface 1A of the ceramic body 1, completing the multilayer ceramic capacitor 200 according to the second embodiment.

[0081] The multilayer ceramic capacitors 100 and 200 according to the embodiments have been described above. However, the present invention is not limited to the above-described content, and various modifications can be made in accordance with the spirit of the invention.

[0082] For example, the above embodiment includes a step of increasing the R dimension of the ridge line E11 where the first main surface 1A and the first end surface 1C meet, the ridge line E12 where the first main surface 1A and the first side surface 1E meet, the ridge line E13 where the first main surface 1A and the second end surface 1D meet, and the ridge line E14 where the first main surface 1A and the second side surface 1F meet, but does not include a step of increasing the R dimension of the ridge line E21 where the second main surface 1B and the first end surface 1C meet, the ridge line E22 where the second main surface 1B and the first side surface 1E meet, the ridge line E23 where the second main surface 1B and the second end surface 1D meet, and the ridge line E24 where the second main surface 1B and the second side surface 1F meet. However, by modifying this and adding a step to increase the radius (R) of each of the following ridges: E21 where the second main surface 1B and the first end surface 1C meet, E22 where the second main surface 1B and the first side surface 1E meet, E23 where the second main surface 1B and the second end surface 1D meet, and E24 where the second main surface 1B and the second side surface 1F meet, and by varying the degree to which the radius is increased in the two steps, the radius of the ridge E11 where the first main surface 1A and the first end surface 1C meet, and the first main The radius (R) of the ridge line E12 where surface 1A and the first side surface 1E meet, the ridge line E13 where the first main surface 1A and the second end surface 1D meet, and the ridge line E14 where the first main surface 1A and the second side surface 1F meet may be made larger than the radius (R) of the ridge line E21 where the second main surface 1B and the first end surface 1C meet, the ridge line E22 where the second main surface 1B and the first side surface 1E meet, the ridge line E23 where the second main surface 1B and the second end surface 1D meet, and the ridge line E24 where the second main surface 1B and the second side surface 1F meet.

[0083] Furthermore, in the above embodiment, embossed holes 10 were formed on the second main surface 1B of the ceramic body 1, but in the multilayer ceramic capacitor of the present invention, the embossed holes 10 are not an essential component and can be omitted.

[0084] A multilayer ceramic capacitor according to one embodiment of the present invention is as described in the "Means for Solving the Problem" section.

[0085] In this multilayer ceramic capacitor, it is also preferable that the radius (R) of the edges where the first main surface and the first end face, second end face, first side surface, and second side surface meet is between 1 μm and 10 μm. If it is less than 1 μm, the effect of suppressing the occurrence of cracks in the ceramic body when these edges collide with a substrate or the like is small. If it exceeds 10 μm, the process of increasing the radius of each of these edges takes time, which reduces the productivity of the multilayer ceramic capacitor.

[0086] Furthermore, it is preferable that the radius (R) of the angles where the first main surface, the first end surface, and the first side surface meet, the angles where the first main surface, the first side surface, and the second end surface meet, the angles where the first main surface, the second end surface, and the second side surface meet, and the angles where the first main surface, the second side surface, and the first end surface meet is larger than the radius (R) of the angles where the second main surface, the first end surface, and the first side surface meet, the angles where the second main surface, the first side surface, and the second end surface meet, and the angles where the second main surface, the second side surface, and the first end surface meet. In this case, the radius radius (R) of the corners where the first main surface, first end surface, and first side surface meet on the mounting side, the corners where the first main surface, first side surface, and second end surface meet, the corners where the first main surface, second end surface, and second side surface meet, and the corners where the first main surface, second side surface, and first end surface meet is large. Therefore, when the multilayer ceramic capacitor is placed on a substrate for mounting, even if these corners collide with the substrate or electrodes formed on the substrate, the impact is mitigated, thus suppressing the occurrence of cracks in the ceramic body.

[0087] Furthermore, it is preferable that multiple embossed holes are formed on the second main surface of the ceramic body. In this case, for example, when the second main surface is adsorbed by the nozzle of the mounting device, even if an impact is applied by the nozzle, the ceramic body is resistant to impact, and the occurrence of cracks or other damage is suppressed.

[0088] It is also preferable that the first external electrode and the second external electrode each include a base external electrode and at least one plated external electrode layer formed on the outside of the base external electrode. In this case, the base external electrode can be used as a base, and the plated external electrode layer can be easily formed on the outside thereon, for example, by electroless plating.

[0089] Furthermore, it is preferable that the underlying external electrode has a smaller length dimension than the first and second internal electrodes and includes a dummy internal electrode exposed on the first main surface of the ceramic body. In this case, the first and second external electrodes, which have a relatively large area on the first main surface of the ceramic body, can be easily formed.

[0090] It is also preferable that the dummy internal electrode, the first internal electrode, and the second external electrode are formed from the same material. In this case, there is no need to prepare separate materials to form the dummy internal electrode, which is the base external electrode, thus improving the productivity of multilayer ceramic capacitors.

[0091] It is also preferable that the dummy internal electrode is mainly composed of Ni. In this case, the ceramic body, the first internal electrode, the second external electrode, and the dummy internal electrode can be easily manufactured by so-called co-firing.

[0092] It is also preferable that the underlying external electrode be a thin film. In this case, the underlying external electrode can be easily formed, for example, by sputtering.

[0093] In this case, it is also preferable for the thin film to have NiCr as its main component. In this case, it has high adhesion to the ceramic substrate and becomes an excellent base external electrode for the first external electrode and the second external electrode.

[0094] It is also preferable that the plated external electrode layer includes at least one selected from a Cu plated external electrode layer, a Ni plated external electrode layer, and an Au plated external electrode layer. In this case, various functions can be exhibited in each plated external electrode layer, and excellent first and second external electrodes can be formed.

[0095] It is also preferable that the plated external electrode layer includes a Ni plated external electrode layer formed on the outside of the underlying external electrode and an Au plated external electrode layer formed on the outside of the Ni plated external electrode layer. In this case, the Ni plated external electrode layer can mainly perform the function of improving solder heat resistance and bonding performance, and the Au plated external electrode layer 9 can mainly perform the function of improving the solder wettability of the external electrode layer.

[0096] It is also preferable that the plated external electrode layer includes a Cu plated external electrode layer formed on the outside of the underlying external electrode, a Ni plated external electrode layer formed on the outside of the Cu plated external electrode layer, and an Au plated external electrode layer formed on the outside of the Ni plated external electrode layer. In this case, the Cu plated external electrode layer 7 can mainly perform the function of improving moisture resistance, the Ni plated external electrode layer can mainly perform the function of improving solder heat resistance and bonding performance, and the Au plated external electrode layer 9 can perform the function of improving the solder wettability of the external electrode layer.

[0097] It is also preferable that the Ni-plated external electrode layer contains phosphorus (P). In this case, the mechanical strength of the external electrode layer is improved.

[0098] It is also preferable that the Cu-plated external electrode layer contains Ni. In this case, the dissolution of the external electrode layer into the solder can be suppressed.

[0099] It is also preferable that one of the dimensions in the length direction and the width direction is 1.0 mm or less, and the other is 0.5 mm or less. Furthermore, it is also preferable that the dimension in the height direction is 0.1 mm or less. In this way, even when the present invention is applied to a miniaturized and thin-layer multilayer ceramic capacitor, the radius (R) of the edges where the first main surface, which is the mounting surface, and the first end face, first side surface, second end face, and second side surface meet is large. Therefore, even if these edges collide with the substrate or electrodes formed on the substrate during mounting, the occurrence of cracks in the ceramic body is suppressed. [Explanation of Symbols]

[0100] 1. Ceramic base 1a. Ceramic layer 1A...First main surface 1B...Second main surface 1C...1st end surface 1D...Second end surface 1E...1st side 1F...2nd side 2...1st internal electrode 3...Second internal electrode 4. Dummy internal electrodes 5...1st external electrode 6...Second external electrode 7. Cu plated external electrode layer 8, 28...Ni plated external electrode layer 9, 29...Au plated external electrode layer 27...NiCr thin film layer (base external electrode) 10 embossed holes

Claims

1. A ceramic body comprising multiple ceramic layers, multiple first internal electrodes, and multiple second internal electrodes stacked in the height direction, having a first main surface and a second main surface facing each other in the height direction, a first end surface and a second end surface facing each other in the length direction perpendicular to the height direction, and a first side surface and a second side surface facing each other in the width direction perpendicular to the height direction and the length direction, The ceramic body comprises a first external electrode and a second external electrode formed on its outer surface, The first internal electrode is drawn out to the first end face and electrically connected to the first external electrode. The multilayer ceramic capacitor is characterized in that the second internal electrode is drawn out to the second end face and electrically connected to the second external electrode, When viewing a cross-section parallel to the first and second sides, The first external electrode is formed in an L-shape on the first end face and the first main face, The second external electrode is formed in an L-shape on the second end face and the first main face, The radius (R) of the first ridge where the first main surface and the first end surface, first side surface, second end surface, and second side surface meet is The radius (R) of the second ridge where the second main surface and the first end surface, the first side surface, the second end surface, and the second side surface meet is greater than the radius (R) of the second ridge. The ceramic of the first ridge portion covered by the first external electrode and the second external electrode has the same composition. The first external electrode and the second external electrode are, Substrate exterior electrode and The aforementioned base external electrode is provided with at least one plated external electrode layer formed on the outside, The aforementioned underlayment external electrode is covered with the aforementioned plated external electrode layer. The height dimension of the ceramic body is 0.1 mm or less. Multilayer ceramic capacitor.

2. The radius (R) of the ridge where the first main surface and the first end surface, first side surface, second end surface, and second side surface meet is, It is between 1 μm and 10 μm. A multilayer ceramic capacitor as described in claim 1.

3. The radius R of the angle where the first main surface, the first end surface, and the first side surface meet, the angle where the first main surface, the first side surface, and the second end surface meet, the angle where the first main surface, the second end surface, and the second side surface meet, and the angle where the first main surface, the second side surface, and the first end surface meet is The radius R of the angle where the second main surface, the first end surface, and the first side surface meet, the angle where the second main surface, the first side surface, and the second end surface meet, the angle where the second main surface, the second end surface, and the second side surface meet, and the angle where the second main surface, the second side surface, and the first end surface meet is greater than the radius R of the angle where the second main surface, the first end surface, and the first side surface meet. A multilayer ceramic capacitor according to claim 1 or 2.

4. Multiple embossed holes are formed on the second main surface. A multilayer ceramic capacitor according to claim 1 or 2.

5. The first external electrode and the second external electrode are, Substrate exterior electrode and Including at least one plated external electrode layer formed on the outside of the aforementioned underlayment external electrode, A multilayer ceramic capacitor according to claim 1 or 2.

6. The aforementioned external electrode for the substrate, A dummy internal electrode having a smaller length dimension than the first internal electrode and the second internal electrode, and exposed on the first main surface of the ceramic body, A multilayer ceramic capacitor as described in claim 5.

7. The dummy internal electrode, the first internal electrode, and the second internal electrode are formed of the same material. A multilayer ceramic capacitor as described in claim 6.

8. The dummy internal electrode is composed mainly of Ni, A multilayer ceramic capacitor as described in claim 6.

9. The aforementioned external electrode of the substrate is a thin film. A multilayer ceramic capacitor as described in claim 5.

10. The thin film is mainly composed of NiCr, A multilayer ceramic capacitor as described in claim 9.

11. The aforementioned plated external electrode layer It includes at least one selected from a Cu-plated external electrode layer, a Ni-plated external electrode layer, and an Au-plated external electrode layer. A multilayer ceramic capacitor as described in claim 5.

12. The aforementioned plated external electrode layer A Ni-plated external electrode layer formed on the outside of the aforementioned base external electrode, Including an Au-plated external electrode layer formed on the outside of the Ni-plated external electrode layer, A multilayer ceramic capacitor as described in claim 11.

13. The aforementioned plated external electrode layer The Cu plated outer electrode layer formed on the outside of the aforementioned base outer electrode, A Ni-plated external electrode layer formed on the outside of the Cu-plated external electrode layer, Including an Au-plated external electrode layer formed on the outside of the Ni-plated external electrode layer, A multilayer ceramic capacitor as described in claim 11.

14. The Ni-plated external electrode layer contains P, A multilayer ceramic capacitor as described in claim 11.

15. The Cu-plated external electrode layer contains Ni, A multilayer ceramic capacitor as described in claim 11.

16. The lengthwise dimension and the widthwise dimension are 1.0 mm or less, and the other is 0.5 mm or less. A multilayer ceramic capacitor according to claim 1 or 2.

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