Multilayer ceramic electronic component, method of manufacturing the same, and circuit board

Abstract

The present application provides a multilayer ceramic electronic component capable of being mounted at high density without problems, a circuit board on which the multilayer ceramic electronic component is mounted at high density, and a manufacturing method of the multilayer ceramic electronic component. A multilayer ceramic electronic component according to one embodiment of the present application includes a ceramic main body and an external electrode. The ceramic main body has an end surface facing a first direction and an internal electrode exposed from the end surface and stacked in a second direction orthogonal to the first direction. The external electrode is provided on the end surface and has two protrusions formed on two peripheral portions of the end surface in a third direction orthogonal to the first direction and the second direction, respectively, and protruding in the first direction.

Description

Technical Field

[0001] The present invention relates to a laminated ceramic electronic component, a circuit board on which the laminated ceramic electronic component is mounted, and a method for manufacturing the laminated ceramic electronic component. Background Technology

[0002] Multilayer ceramic electronic components, such as multilayer ceramic capacitors, are electrically connected to electrode pads on a printed circuit board via solder, as shown in Patent Document 1. The solder bonds the surface of the external electrodes of the multilayer ceramic electronic component to the electrode pads.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-197572 (paragraphs

[0101]

[0102] ) Figure 4 and Figure 5 ) Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In recent years, multilayer ceramic electronic components have sometimes been mounted on substrates at high densities. When the mounting density is high, there is a possibility that the solder formed on the external electrodes of adjacent multilayer ceramic electronic components may fuse together, causing short circuits and other problems.

[0008] In view of the above, the object of the present invention is to provide a stacked ceramic electronic component that can be mounted at high density without problems, a circuit board on which the stacked ceramic electronic component is mounted at high density, and a method for manufacturing the stacked ceramic electronic component.

[0009] Technical solutions for solving technical problems

[0010] To achieve the above objectives, one embodiment of the present invention relates to a stacked ceramic electronic component comprising a ceramic body and external electrodes.

[0011] The ceramic body has an end face facing a first direction and internal electrodes exposed from the end face and stacked in a second direction orthogonal to the first direction.

[0012] The external electrode is disposed on the end face and has two protrusions. The two protrusions are formed on two peripheral portions of the end face in a third direction orthogonal to the first direction and the second direction and protrude toward the first direction.

[0013] Multilayer ceramic electronic components are mounted to a substrate by soldering external electrodes to the substrate. In the above structure, the external electrodes have protrusions at their two peripheral portions along the third direction, thus resulting in a larger surface area compared to a structure with a convex central portion. Solder wets the surface of the external electrodes, and because the solder wets the surfaces of the two protrusions, the solder thickness can be thinner compared to a structure with a convex central portion. Therefore, even when soldering multiple multilayer ceramic electronic components with their external electrodes close together in the first direction, the solder thickness on both external electrodes can be limited, preventing the solder from fusing together. This allows for high-density mounting without problems.

[0014] For example, the dimensions of each of the two protrusions in the third direction may be 15 μm or more and 60 μm or less.

[0015] For example, the dimensions of each of the two protrusions in the first direction may be 10 μm or more and 20 μm or less.

[0016] For example, the two convex portions could also be the tops that protrude most towards the first direction in the cross-section viewed from the second direction.

[0017] The distance between the tops of the two protrusions in the third direction is 250 μm or more and 285 μm or less.

[0018] Another aspect of the present invention relates to a circuit board comprising a mounting substrate having a mounting surface, two stacked ceramic electronic components, and solder.

[0019] The two stacked ceramic electronic components are arranged in the first direction and each has a ceramic body and an external electrode. The ceramic body has an end face facing the first direction and an internal electrode that is exposed from the end face and stacked in a second direction orthogonal to the first direction. The external electrode is connected to the mounting surface and disposed on the end face.

[0020] The aforementioned solder bonds the surface of the external electrode to the mounting surface.

[0021] The external electrode has a protrusion that is formed along the periphery of the end face and protrudes in the first direction.

[0022] The distance between the external electrodes of the two stacked ceramic electronic components in the first direction is less than 100 μm.

[0023] In the above structure, the external electrode has a protrusion along its periphery, thus providing a larger surface area compared to a structure with a convex central portion. Solder wets the surface of the external electrode, thus wetting the surface of the protrusion, allowing for a thinner solder layer compared to a structure with a convex central portion. Therefore, when the external electrodes of two stacked ceramic electronic components are soldered at a distance of 100 μm or less in the first direction, the solder thickness on both external electrodes can be limited, preventing solder from bonding together. This enables high-density mounting.

[0024] For example, the external electrode may have two protrusions, which are formed on two peripheral portions of the end face in a third direction orthogonal to the first and second directions and protrude toward the first direction.

[0025] Another aspect of the present invention relates to a method for manufacturing a stacked ceramic electronic component, which includes a step of fabricating a ceramic body having an end face facing a first direction and internal electrodes exposed from the end face and stacked in a second direction orthogonal to the first direction.

[0026] An external electrode with two protrusions is formed on the end face. The two protrusions are formed on two peripheral portions of the end face in a third direction orthogonal to the first direction and the second direction and protrude toward the first direction.

[0027] Alternatively, a recess and two protrusions can be formed on the end face, wherein the recess is formed at the center in the third direction, and the two protrusions are respectively located outside the recess in the third direction and protrude in the first direction.

[0028] The two protrusions of the external electrode are respectively formed on the two protrusions of the end face.

[0029] Invention Effects

[0030] As described above, according to the present invention, it is possible to provide a stacked ceramic electronic component that can be mounted at high density without problems, a circuit board on which the stacked ceramic electronic component is mounted at high density, and a method for manufacturing the stacked ceramic electronic component. Attached Figure Description

[0031] Figure 1 This is a perspective view of a multilayer ceramic capacitor according to one embodiment of the present invention.

[0032] Figure 2 It is along the above-mentioned multilayer ceramic capacitor Figure 1 A cross-sectional view of line A-A'.

[0033] Figure 3 It is along the above-mentioned multilayer ceramic capacitorFigure 1 A cross-sectional view of line B-B'.

[0034] Figure 4 This is a top view of the aforementioned multilayer ceramic capacitor.

[0035] Figure 5 This is a cross-sectional view of a circuit board equipped with the aforementioned multilayer ceramic capacitors.

[0036] Figure 6 This is a top view of the aforementioned circuit board.

[0037] Figure 7 This is a top view of the circuit board involved in the comparative example of the above-described embodiments.

[0038] Figure 8 This is a flowchart illustrating the manufacturing method of the aforementioned multilayer ceramic capacitor.

[0039] Figure 9 This is a three-dimensional diagram illustrating the manufacturing process of the aforementioned multilayer ceramic capacitor.

[0040] Figure 10 This is a top view showing the manufacturing process of the aforementioned multilayer ceramic capacitor.

[0041] Figure 11 This is a top view showing the manufacturing process of the aforementioned multilayer ceramic capacitor.

[0042] Figure 12 This is a three-dimensional diagram illustrating the manufacturing process of the aforementioned multilayer ceramic capacitor.

[0043] Figure 13 This is a perspective view of a multilayer ceramic capacitor according to other embodiments of the present invention.

[0044] Explanation of reference numerals in the attached figures

[0045] 10, 20... Multilayer ceramic capacitors (multilayer ceramic electronic components)

[0046] 11... Ceramic body

[0047] 11a……End face

[0048] 14, 24... External electrodes

[0049] 18, 28...convex part

[0050] 50……Mounting substrate

[0051] 51……Mounting surface

[0052] 60... Solder. Detailed Implementation

[0053] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0054] In the graph, the X, Y, and Z axes are appropriately represented as mutually orthogonal. The X, Y, and Z axes are the same in all graphs.

[0055] 1. Structure of the multilayer ceramic capacitor 10

[0056] Figures 1-3 This is a diagram illustrating a multilayer ceramic capacitor 10 according to one embodiment of the present invention. Figure 1 This is a three-dimensional view of the multilayer ceramic capacitor 10. Figure 2 It is the edge of the multilayer ceramic capacitor 10 Figure 1 A cross-sectional view of line A-A'. Figure 3 It is the edge of the multilayer ceramic capacitor 10 Figure 1 A cross-sectional view of line B-B'.

[0057] The multilayer ceramic capacitor 10 includes a ceramic body 11 and an external electrode 14.

[0058] The ceramic body 11 has two end faces 11a facing the X-axis, two side faces 11b facing the Y-axis, and two main faces 11c facing the Z-axis. An external electrode 14 is provided on the end faces 11a. The edges connecting the faces of the ceramic body 11 may also be chamfered. The faces of the ceramic body 11 are not limited to flat surfaces; they may also be curved or have irregularities. For example, the end faces 11a may, as described later, have a shape where the periphery in the Y-axis direction protrudes towards the X-axis.

[0059] The ceramic body 11 has a capacitor forming portion 16 and a protective portion 17. The capacitor forming portion 16 has a plurality of first internal electrodes 12 and a plurality of second internal electrodes 13, which have a structure in which multiple ceramic layers 15 are alternately stacked in the Z-axis direction. The protective portion 17 covers the surface of the capacitor forming portion 16 facing the main surface 11c in the Z-axis direction and the side surface 11b in the Y-axis direction, respectively.

[0060] The first internal electrode 12 is led out to one end face 11a, spaced apart from the other end face 11a. The second internal electrode 13 is spaced apart from the end face 11a to which the first internal electrode 12 is led out, and is led out to the other end face 11a.

[0061] The internal electrodes 12 and 13 are typically composed primarily of nickel (Ni) and function as internal electrodes of the multilayer ceramic capacitor 10. In addition to nickel, the internal electrodes 12 and 13 can also be composed primarily of copper (Cu), silver (Ag), palladium (Pd), etc.

[0062] The ceramic layer 15 is formed of dielectric ceramic. In order to increase the capacitance of the capacitor forming part 16, the ceramic layer 15 is formed of dielectric ceramic with a high dielectric constant.

[0063] As the dielectric ceramic with the aforementioned high dielectric constant, a polycrystalline material of barium titanate (BaTiO3) is used, that is, a polycrystalline material with a perovskite structure containing barium (Ba) and titanium (Ti). Thus, a multilayer ceramic capacitor 10 with a large capacitance can be obtained.

[0064] Alternatively, the ceramic layer 15 can also be formed from strontium titanate (SrTiO3), calcium titanate (CaTiO3), magnesium titanate (MgTiO3), calcium zirconate (CaZrO3), calcium zirconate titanate (Ca(Zr,Ti)O3), barium zirconate (BaZrO3), titanium oxide (TiO2), etc.

[0065] The protective section 17 is also formed of dielectric ceramic. The material forming the protective section 17 can be any insulating ceramic, but by using the same dielectric ceramic as the ceramic layer 15, the internal stress in the ceramic body 11 can be suppressed.

[0066] The protective portion 17 covers the surface of the capacitor forming portion 16 other than the end face 11a. The protective portion 17 mainly protects the area around the capacitor forming portion 16 and has the function of ensuring the insulation of the internal electrodes 12 and 13. Hereinafter, the area on the main surface 11c side of the protective portion 17 will be referred to as the covered area, and the area on the side surface 11b side will be referred to as the side edge area.

[0067] An external electrode 14 is disposed on an end face 11a and extends to the main face 11c and the side face 11b. One external electrode 14 is connected to the first internal electrode 12 on one end face 11a, and the other external electrode 14 is connected to the second internal electrode 13 on the other end face 11a.

[0068] The detailed structure of the external electrode 14 will be described below.

[0069] 2. Detailed structure of external electrode 14

[0070] Figure 4 This is a top view of the stacked ceramic capacitor 10 as seen from the Z-axis direction.

[0071] like Figure 1 and 4 As shown, the external electrode 14 has a first surface 14a facing the X-axis, a second surface 14b facing the Y-axis, and a third surface 14c facing the Z-axis. The first surface 14a is formed on the end surface 11a. In this embodiment, the second surface 14b is formed on the side surface 11b. In this embodiment, the third surface 14c is formed on the main surface 11c.

[0072] like Figure 1and 4 As shown, the external electrode 14 has two protrusions 18, each formed on one of the two peripheral portions of its end face 11a along the Y-axis direction and protruding in the X-axis direction. The peripheral portion of the end face 11a in the Y-axis direction is located at the periphery of the end face 11a in the Y-axis direction and extends along the outer edge of the end face 11a in the Z-axis direction. The two protrusions 18 are also configured to extend along the Z-axis direction on the first surface 14a.

[0073] Each protrusion 18 includes a top 18a that protrudes most prominently in the X-axis direction in a cross-section viewed from the Z-axis direction. Each top 18a is also configured to extend in the Z-axis direction. The shape of the top 18a is not particularly limited; for example, the top 18a can be a convex curved surface or a sharply protruding surface. Furthermore, the position of the top 18a is not limited to the center of the protrusion 18 in the Y-axis direction, but can be offset towards the Y-axis direction.

[0074] In this embodiment, the external electrode 14 also has a central portion 19 on the first surface 14a, which is located between two protrusions 18 spaced apart in the Y-axis direction. The central portion 19 has a generally flat structure in this embodiment, but it may also have minute irregularities with a protrusion of less than 1 μm in the X-axis direction.

[0075] Since the external electrode 14 has two protrusions 18 spaced apart from each other in the Y-axis direction, the surface area of ​​the external electrode 14 can be increased. As a result, as will be described later, the thickness of the solder covering the surface of the external electrode 14 can be reduced when it is mounted to the mounting substrate.

[0076] The width dimension D1 of each protrusion 18 in the Y-axis direction can be, for example, 15 μm or more. This ensures that the width dimension D1 of each protrusion 18 is sufficiently large, and thus ensures a sufficiently large surface area for each protrusion 18. The width dimension D1 of each protrusion 18 is the dimension of the largest portion in the Y-axis direction of each protrusion 18.

[0077] The ratio of the width dimension D1 to the width dimension W of the multilayer ceramic capacitor 10, D1 / W, can be, for example, 0.02 or higher. The width dimension W of the multilayer ceramic capacitor 10 is the dimension of the largest portion in the Y-axis direction of the multilayer ceramic capacitor 10.

[0078] Furthermore, the width dimension D1 can be, for example, 60 μm or less, and the ratio of the width dimension D1 to the width dimension W of the multilayer ceramic capacitor 10, D1 / W, can be, for example, 0.20 or less.

[0079] Furthermore, the distance D2 in the Y-axis direction between the tops 18a of the two protrusions 18 can be, for example, 250 μm or more. This ensures that the tops 18a of the protrusions 18 are sufficiently spaced in the Y-axis direction, suppressing localized solder concentration. The distance D2 is the distance between the tops 18a of the two protrusions 18 at their largest distance in the Y-axis direction.

[0080] The ratio of distance D2 to the width dimension W of the multilayer ceramic capacitor 10, D2 / W, can be, for example, 0.30 or more. Furthermore, distance D2 can be, for example, 285 μm or less, and the ratio of distance D2 to the width dimension W of the multilayer ceramic capacitor 10, D2 / W, can be, for example, 0.95 or less.

[0081] The height dimension D3 of the top 18a in the X-axis direction can be, for example, 10 μm or more. This allows the protrusion 18 to protrude sufficiently, ensuring adequate surface area of ​​the protrusion 18. The height dimension D3 of the top 18a is the height dimension in the X-axis direction from the thinnest part of the central portion 19 to the top 18a.

[0082] The ratio of the height dimension D3 to the thickness dimension D4 of the central portion 19, D3 / D4, can be, for example, 0.25 or higher. (See reference...) Figure 2 The thickness dimension D4 of the central part 19 is the thickness dimension of the thinnest part in the X-axis direction of the central part 19.

[0083] Furthermore, the height dimension D3 can be, for example, 20 μm or less, and the ratio of the height dimension D3 to the thickness dimension D4 of the central portion 19, D3 / D4, can be, for example, 0.50 or less.

[0084] By connecting the external electrode 14 of the above structure to the mounting substrate with solder, a circuit board having a multilayer ceramic capacitor 10 can be constructed.

[0085] 3. Structure of circuit board 100

[0086] Figure 5 and 6 This is a diagram showing the circuit board 100 involved in this embodiment. Figure 5 Is with Figure 2 A cross-sectional view of the circuit board 100 at the corresponding location. Figure 6 This is a top view of the circuit board 100 as seen from the Z-axis direction.

[0087] The circuit board 100 includes a mounting substrate 50 with a mounting surface 51, at least two stacked ceramic capacitors 10, and solder 60. Additionally, Figure 5 This is a cross-sectional view of the portion of the circuit board 100 in which a multilayer ceramic capacitor 10 is mounted. Figure 6This indicates the case where two stacked ceramic capacitors 10 are arranged side by side, but the circuit board 100 may also have three or more stacked ceramic capacitors 10.

[0088] Mounting surface 51 includes solder pads 52 that connect to external electrodes 14. Solder pads 52 are pad-shaped metal terminals disposed on mounting surface 51, for example, in a rectangular configuration. For example, one solder pad 52 is provided for each of the external electrodes 14. The portion of mounting surface 51 other than the solder pads 52, although not shown, is covered, for example, by an insulating solder resist layer.

[0089] The multilayer ceramic capacitor 10 is disposed on the mounting surface 51, for example, with one of its main surfaces 11c facing the mounting surface 51. Figure 6 As shown, two stacked ceramic capacitors 10 are arranged side by side in the X-axis direction. The distance D5 between the external electrodes 14 of the two stacked ceramic capacitors 10 in the X-axis direction is, for example, 100 μm or less, more preferably 80 μm or less. Furthermore, the distance D5 is the distance of the narrowest part in the X-axis direction between the external electrodes 14 of the two adjacent stacked ceramic capacitors 10.

[0090] Solder 60 bonds the surface of the external electrode 14 to the mounting surface 51. Solder 60 is disposed between the pad 52 and the third surface 14c of the external electrode 14, and is formed in such a way that it extends to the second surface 14b of the external electrode 14 and the first surface 14a having a protrusion 18.

[0091] The circuit board 100 is manufactured, for example, as follows: First, solder paste is applied to the pads 52 of the mounting substrate 50, and a multilayer ceramic capacitor 10 is disposed on the solder paste. In this state, the solder paste is heated in a reflow oven and melted. As the solder paste melts, the multilayer ceramic capacitor 10 sinks towards the pads 52. Thus, the solder paste wets from the third surface 14c of the external electrode 14 to the first surface 14a and the second surface 14b. Afterward, the solder paste cools and solidifies, thereby forming solder 60 connecting the external electrode 14 and the mounting substrate 50, thus manufacturing the circuit board. Figure 5 and Figure 6 The circuit board 100 shown.

[0092] Here, upon reaching the first surface 14a, the molten solder paste flows from the less undulating portion in the X-axis direction to the convex portion. That is, the solder paste flows from the central portion 19 to the two protrusions 18, covering each protrusion 18. Therefore, by employing a multilayer ceramic capacitor 10, localized concentration of the solder paste can be suppressed. Furthermore, the surface area on the external electrode 14 can be increased by utilizing the two protrusions 18. Thus, the thickness of the solder 60 on the first surface 14a can be suppressed.

[0093] Figure 7This is a diagram showing the circuit board 300 involved in the comparative example of this embodiment, and is a top view of the circuit board 300 viewed from the Z-axis direction. Furthermore, in the circuit board 300, the same reference numerals are used to label the same structures as those in the circuit board 100 described above, and descriptions are omitted.

[0094] The circuit board 300 includes a mounting substrate 50 having a mounting surface 51, at least two multilayer ceramic capacitors 30, and solder 70. The circuit board 300 has the same mounting substrate 50 as the circuit board 100, but the structure of the multilayer ceramic capacitors 30 is different from that of the circuit board 100.

[0095] The multilayer ceramic capacitor 30 includes a ceramic body 31 and two external electrodes 34. The external electrodes 34 have a first surface 34a facing the X-axis, a second surface 34b facing the Y-axis, and a third surface 34c facing the Z-axis. The central portion of the first surface 34a in the Y-axis direction is convex in the X-axis direction.

[0096] In circuit board 300, the pads 52 of mounting surface 51 are configured the same as in circuit board 100, so the distance D6 between adjacent external electrodes 34 in the X-axis direction is approximately the same as the distance D5 on circuit board 100. Furthermore, the amount of solder paste applied to form solder 70 is approximately the same as the amount of solder paste applied to form solder 60.

[0097] When manufacturing circuit board 300, when the molten solder paste reaches the first surface 34a, the solder paste flows from the peripheral portion in the Y-axis direction of the first surface 34a towards the convex central portion in the Y-axis direction. As a result, the solder paste easily concentrates in the central portion in the Y-axis direction, and the solidified solder 70 forms a thick, raised shape in the central portion in the Y-axis direction. In cases where the distance D6 is small, such as... Figure 7 As shown, the solder 70 formed on adjacent multilayer ceramic capacitors 30 tends to fuse at the center in the Y-axis direction. When the solder 70 of different multilayer ceramic capacitors 30 fuses, not only are there cosmetic problems, but electrical problems such as short circuits may also occur.

[0098] On the other hand, in this embodiment, the molten solder paste flows in a manner that covers the surfaces of the two protrusions 18. Therefore, when the amount of solder paste used is approximately the same as that of solder 70, the amount of solder 60 protruding from each protrusion 18 is small. That is, in this embodiment, the surface area of ​​the first surface 14a can be increased, and the local concentration of solder 60 can be prevented, thus suppressing the thickness of solder 60. As a result, even when the multilayer ceramic capacitors 10 are mounted at high density with a distance of D5 of 100 μm or less, problems such as the fusion of adjacent solder 60 can be prevented.

[0099] Therefore, in this embodiment, the problem of solder 60 fusion formed in adjacent stacked ceramic capacitors 10 can be suppressed, and electrical problems such as appearance and short circuits can be suppressed.

[0100] Such a multilayer ceramic capacitor 10 can be manufactured, for example, as follows.

[0101] 4. Manufacturing method of multilayer ceramic capacitor 10

[0102] Figure 8 This is a flowchart illustrating the manufacturing method of the multilayer ceramic capacitor 10. Figures 9-12 This is a diagram illustrating the manufacturing process of the multilayer ceramic capacitor 10. The following is in accordance with... Figure 8 and refer to appropriately Figures 9-12 The manufacturing method of the multilayer ceramic capacitor 10 is described.

[0103] 4.1 Step S01: Ceramic sheet stacking

[0104] In step S01, by means of Figure 9 The first ceramic sheet 101, the second ceramic sheet 102, and the third ceramic sheet 103 are stacked as shown to form a laminated sheet 104.

[0105] Ceramic sheets 101, 102, and 103 are constructed as unfired dielectric green sheets with dielectric ceramic as the main component. An unfired first internal electrode 112 is formed on the first ceramic sheet 101. An unfired second internal electrode 113 is formed on the second ceramic sheet 102. No internal electrode is formed on the third ceramic sheet 103.

[0106] Figure 10 This is a top view of ceramic sheets 101 and 102. At this stage, ceramic sheets 101 and 102 are constructed as large, un-monolithified sheets. Figure 10 The numbers Lx, Ly1, and Ly2 represent the cutting lines when each of the stacked ceramic capacitors 10 is monolithically processed. Cutting line Lx is parallel to the X-axis, and cutting lines Ly1 and Ly2 are parallel to the Y-axis.

[0107] The internal electrodes 112 and 113 can be formed by coating the ceramic sheets 101 and 102 with any conductive paste. The coating method of the conductive paste can be selected from any known technology. For example, screen printing or gravure printing can be used in the coating of the conductive paste.

[0108] The internal electrodes 112 and 113 on the ceramic sheets 101 and 102 are configured as approximately rectangular shapes extending in the X-axis direction across a cutting line Ly1 or Ly2. The internal electrodes 112 and 113 are cut along cutting lines Ly1, Ly2, and Lx to form the internal electrodes 12 and 13 of each multilayer ceramic capacitor 10. Cutting lines Ly1 and Ly2 correspond to the end face 11a of each multilayer ceramic capacitor 10. Cutting line Lx corresponds to the side face 11b of each multilayer ceramic capacitor 10.

[0109] In the first ceramic sheet 101, the first and second columns are arranged alternately in the Y-axis direction. The first column consists of internal electrodes 112 extending across dicing line Ly1 arranged in the X-axis direction, and the second column consists of internal electrodes 112 extending across dicing line Ly2 arranged in the X-axis direction. In the first column, adjacent internal electrodes 112 in the X-axis direction are positioned opposite each other across dicing line Ly2. In the second column, adjacent internal electrodes 112 in the X-axis direction are positioned opposite each other across dicing line Ly1. That is, in the adjacent first and second columns in the Y-axis direction, the internal electrodes 112 are staggered in the X-axis direction by an amount equal to one chip.

[0110] The internal electrode 113 on the second ceramic sheet 102 is also constructed in the same manner as the internal electrode 112. However, on the second ceramic sheet 102, the internal electrode 113 in the column corresponding to the first column of the first ceramic sheet 101 extends across the cutting line Ly2, and the internal electrode 113 in the column corresponding to the second column of the first ceramic sheet 101 extends across the cutting line Ly1. That is, the internal electrode 113 and the internal electrode 112 are formed staggered by one chip in the X-axis direction or Y-axis direction.

[0111] like Figure 9 As shown, the first ceramic sheet 101 and the second ceramic sheet 102 are alternately stacked in the Z-axis direction. The stack of ceramic sheets 101 and 102 corresponds to the unfired capacitor forming portion 16. A third ceramic sheet 103 is stacked on the upper and lower surfaces of the stack of ceramic sheets 101 and 102 in the Z-axis direction. The stack of the third ceramic sheet 103 corresponds to the covered area of ​​the unfired protective portion 17.

[0112] The stacked ceramic sheets 101, 102, and 103 are pressed together to form a single unit. This allows for the fabrication of large-sized stacked sheets 104.

[0113] 4.2 Step S02: Formation of through hole H

[0114] In step S02, through holes H are formed on the cutting lines Ly1 and Ly2 of the laminate 104, extending through the Z-axis direction.

[0115] Figure 11 This is a top view of the laminate 104 viewed along the Z-axis. (Example) Figure 11As shown, the through-hole H extends along the cut lines Ly1 and Ly2 of the laminate 104 without crossing the cut line Lx. That is, the through-hole H is formed in the center of the region of the laminate 104 corresponding to the end face 11a of each laminated ceramic capacitor 10 in the Y-axis direction.

[0116] The through hole H is formed, for example, by cutting with a drill bit or the like. Alternatively, the through hole H can also be formed by laser processing. Furthermore, the shape of the through hole H is not limited to the oblong shape shown in the figure, but can be appropriately adjusted according to the shape of the protrusion 111d of the end face 111a, which will be described later.

[0117] 4.3 Step S03: Cutting

[0118] In step S03, an unfired ceramic body 111 is made by cutting the laminated sheet 104 obtained in step S02 along the cutting lines Lx, Ly1, and Ly2.

[0119] Figure 12 This is a three-dimensional view of the ceramic body 111 obtained in step S03.

[0120] As shown in the figure, the unfired ceramic body 111 has two end faces 111a facing the X-axis, two side faces 111b facing the Y-axis, and two main faces 111c facing the Z-axis. Furthermore, the unfired ceramic body 111 has: an unfired capacitor-forming portion 116 formed by alternating layers of unfired internal electrodes 112 and 113 in the Z-axis direction; and an unfired protective portion 117 surrounding the capacitor-forming portion 116.

[0121] In this embodiment, end face 111a has: a recess 111e formed in the central portion in the Y-axis direction; and two protrusions 111d, which are respectively located outside the recess 111e in the Y-axis direction and protrude in the X-axis direction. In this embodiment, the recess 111e is a concave portion formed by the through hole H. In this embodiment, the protrusions 111d are portions that protrude from the recess 111e in the X-axis direction, corresponding to the areas on the cutting lines Ly1 and Ly2 where the through hole H is not formed.

[0122] The most prominent top of the protrusion 111d is not limited to, for example Figure 12 The structure, which is generally flat as shown, can also be a convex curved surface, or it can be a sharp protrusion. Furthermore, the dimensions of the protrusion 111d can be appropriately set according to the dimensions of the protrusion 18 of the external electrode 14.

[0123] 4.4 Step S04: Firing

[0124] In step S04, the unfired ceramic body 111 obtained in step S03 is sintered to produce... Figures 1-4The ceramic body 11 shown can be fired, for example, in a reducing atmosphere or a low oxygen partial pressure atmosphere. Furthermore, the fired ceramic body 11 can be chamfered by tumbling or similar methods. Thus, the protrusion of the fired end face 11a also becomes a rounded shape.

[0125] 4.5 Step S05: Formation of external electrode 14

[0126] In step S05, an external electrode 14 is formed using the ceramic body 11 obtained in step S04 to fabricate... Figures 1-4 The stacked ceramic capacitor 10 shown.

[0127] In step S05, firstly, a conductive paste is applied to cover one end face 11a of the ceramic body 11, and then another conductive paste is applied to cover the other end face 11a of the ceramic body 11. The conductive paste applied to the ceramic body 11 is then sintered, for example, under a reducing atmosphere or a low oxygen partial pressure atmosphere, to form a base film on the ceramic body 11. Then, a plating process such as electroplating is performed on the base film sintered onto the ceramic body 11 to form a coating, thus completing the external electrode 14.

[0128] The conductive paste used to form the external electrode 14 is applied in a shape mimicking the end face 11a, including the protrusions. Consequently, the base film to which the conductive paste is bonded also has a shape with two protrusions formed at its periphery along the Y-axis direction of the end face 11a. Furthermore, the coating on the base film also mimics the shape of the base film, having protrusions. That is, two protrusions 18 of the external electrode 14 are formed on the two protrusions of the end face 11a.

[0129] Alternatively, some of the processing described in step S05 can be performed before step S04. For example, unfired electrode material can be applied to both end faces 111a of the unfired ceramic body 111 before step S04. In step S04, the unfired electrode material is sintered to form the base layer of the external electrode 14 while the unfired ceramic body 111 is being fired. Furthermore, unfired electrode material can be applied to the ceramic body 111 after the binder removal treatment, and firing can be performed simultaneously.

[0130] 5. Other implementation methods

[0131] For example, the external electrode 14 is not limited to a shape having two protrusions 18.

[0132] Figure 13 This is a perspective view showing a multilayer ceramic capacitor 20 according to another embodiment of the present invention. Furthermore, regarding the multilayer ceramic capacitor 20, the same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted.

[0133] The multilayer ceramic capacitor 20 includes a ceramic body 11 and an external electrode 24. The structure of the external electrode 24 is different from that of the external electrode 14 in the above embodiment.

[0134] The external electrode 24 has a protrusion 28 formed along the periphery of the end face 11a and protruding in the X-axis direction. Specifically, the protrusion 28 includes: a first protrusion 28a formed along two periphery portions in the Y-axis direction of the end face 11a; and a second protrusion 28b formed along two periphery portions in the Z-axis direction of the end face 11a. These first protrusions 28a and second protrusions 28b are connected to form a ring.

[0135] Such external electrodes 24 and Figure 7 Compared to the external electrode 34 of the multilayer ceramic capacitor 30 shown, the surface area is also larger due to the annular protrusion 28. Therefore, during mounting to the mounting substrate, the area for solder paste wetting is increased, and solder thickness can be suppressed. Thus, even when the multilayer ceramic capacitor 20 is mounted at high density on the mounting substrate, problems such as fusion of adjacent solder pieces can be prevented.

[0136] The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.

[0137] For example, the manufacturing method of the multilayer ceramic capacitor 10 is not limited to the method described above. For example, after forming a ceramic body 11 with a generally cuboid shape without protrusions 111d, conductive paste is applied only to the peripheral portion in the Y-axis direction of the end face 11a, and then conductive paste is applied to the entire end face 11a, thereby also forming a multilayer ceramic capacitor 10. Figures 1-4 The external electrode 14 is shown. Alternatively, after forming a generally cuboid ceramic body 11 without protrusions 111d, conductive paste is applied to the entire end face 11a, and then conductive paste is applied only to the peripheral portion of the end face 11a in the Y-axis direction, thereby also forming... Figures 1-4 The external electrode 14 is shown.

[0138] Furthermore, while the multilayer ceramic capacitors 10 and 20 have been described as examples of multilayer ceramic electronic components in the above embodiments, the present invention is applicable to all multilayer ceramic electronic components having a pair of external electrodes. Examples of such multilayer ceramic electronic components include surface mount varistors, surface mount thermistors, and multilayer inductors.

Claims

1. A laminated ceramic electronic component, characterized in that, include: A ceramic body having an end face facing a first direction and internal electrodes exposed from the end face and stacked in a second direction orthogonal to the first direction; as well as The external electrode disposed on the end face has two protrusions, which are formed on two peripheral portions of the end face in a third direction orthogonal to the first and second directions and protrude toward the first direction. The dimensions of each of the two protrusions in the third direction are between 15 μm and 60 μm.

2. The laminated ceramic electronic component as described in claim 1, characterized in that: The dimensions of each of the two protrusions in the first direction are between 10 μm and 20 μm.

3. The laminated ceramic electronic component as described in claim 1 or 2, characterized in that: The two convex portions are respectively the tops that protrude most prominently in the cross-section viewed from the second direction toward the first direction. The distance between the tops of the two protrusions in the third direction is more than 250 μm and less than 285 μm.

4. A circuit board, characterized in that, include: A mounting base plate with a mounting surface; Two stacked ceramic electronic components are arranged side-by-side in a first direction, each having a ceramic body and an external electrode. The ceramic body has an end face facing the first direction and an internal electrode exposed from the end face and stacked in a second direction orthogonal to the first direction. The external electrode is connected to the mounting surface and disposed on the end face. Solder that bonds the surface of the external electrode to the mounting surface. The external electrode has two protrusions, which are formed on two peripheral portions of the end face in a third direction orthogonal to the first and second directions, and protrude toward the first direction. The distance between the external electrodes of the two stacked ceramic electronic components in the first direction is less than 100 μm. The dimensions of each of the two protrusions in the third direction are between 15 μm and 60 μm.

5. A method for manufacturing a laminated ceramic electronic component, characterized in that: A ceramic body is fabricated, the ceramic body having an end face facing a first direction and internal electrodes exposed from the end face and stacked in a second direction orthogonal to the first direction. An external electrode with two protrusions is formed on the end face, wherein the two protrusions are formed on two peripheral portions of the end face in a third direction orthogonal to the first direction and the second direction, and protrude toward the first direction. The dimensions of each of the two protrusions in the third direction are between 15 μm and 60 μm.

6. The method for manufacturing a laminated ceramic electronic component as described in claim 5, characterized in that: A recess and two protrusions are formed on the end face, wherein the recess is formed at the center in the third direction, and the two protrusions are respectively located outside the recess in the third direction and protrude towards the first direction. The two protrusions of the external electrode are respectively formed on the two protrusions of the end face.

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