Multilayer ceramic electronic component and circuit board

Abstract

To provide a laminated ceramic electronic component in which voids are less likely to occur in solder during mounting.SOLUTION: A multilayer ceramic electronic component includes a ceramic body and an end external electrode. The ceramic body includes a main surface, an end surface, and a side surface respectively perpendicular to a first axis, a second axis, and a third axis that are orthogonal to each other, and a top portion connecting the main surface, the end surface, and the side surface, and a plurality of internal electrodes stacked in the first axial direction. The end external electrode includes a corner portion positioned on the top portion, a base portion covering the end surface and extending from the end surface to the main surface and the side surface, and a projecting portion projecting from the base portion in a thickness direction. The projecting portion includes an L-shaped main surface projecting portion located on the main surface and extending from the corner portion in the second axial direction and the third axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic electronic component and a circuit board having external electrodes.

Background Art

[0002] When mounting a multilayer ceramic capacitor using solder, voids may occur due to air mixing into the solder. As a result, heat dissipation of the multilayer ceramic capacitor tends to be hindered, and cracks starting from the voids are likely to occur. Therefore, a technique for preventing voids from occurring in the solder is required.

[0003] Patent Document 1 discloses a multilayer ceramic capacitor configured such that air mixed into the solder during mounting easily escapes to the outside. Specifically, in this multilayer ceramic capacitor, rotation is generated by the surface tension acting on the external electrode from the molten solder, thereby promoting the release of air from the molten solder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to prevent voids from occurring in the solder, it is also effective to release the air mixed into the solder in the molten state as described above, but it is considered that it is more effective to prevent air from mixing into the solder in the first place. That is, a technique capable of suppressing air mixing into the solder when mounting a multilayer ceramic capacitor is required.

[0006] In view of the above circumstances, an object of the present invention is to provide a multilayer ceramic electronic component and a circuit board in which voids are less likely to occur in the solder during mounting.

Means for Solving the Problem

[0007] In order to achieve the above object, a multilayer ceramic electronic component according to one embodiment of the present invention includes a ceramic body and end external electrodes. The ceramic body has main surfaces, end surfaces, and side surfaces perpendicular to a first axis, a second axis, and a third axis orthogonal to each other, a top portion connecting the main surfaces, the end surfaces, and the side surfaces, and a plurality of internal electrodes stacked in the first axis direction. The end external electrodes have a corner portion located on the top portion, a base portion covering the end surface and extending from the end surface to the main surface and the side surfaces, and a protruding portion protruding from the base portion. The protruding portion includes an L-shaped main surface protruding portion located on the main surface and extending from the corner portion in the second axis direction and the third axis direction. and a side surface protrusion extending in the first axial direction from the main surface protrusion along the side surface including. The protruding amount of the main surface protruding portion from the base portion is preferably 3 μm or more and 50 μm or less. The protruding amount of the main surface protruding portion from the base portion is preferably 5 μm or more and 30 μm or less. The protruding portion may further include an end surface protruding portion extending in the first axis direction from the main surface protruding portion along the end surface. The protruding amount of the end surface protruding portion from the base portion is preferably 3 μm or more and 50 μm or less. 。 On The protruding amount of the side surface protruding portion from the base portion is preferably 3 μm or more and 50 μm or less.

[0008] In this configuration, by providing a protruding portion at the corner portion of the end external electrode, the solder sequentially wets and spreads around the corner portion during mounting. In this way, by prescribing in advance the flow of the solder when it wets and spreads on the end external electrode, the mixing of air into the solder during the process of wetting and spreading on the end external electrode is effectively suppressed, so that voids are less likely to occur in the solder. In particular, by providing an L-shaped main surface protruding portion on the end portion external electrode, in a region of the end portion external electrode facing the connection electrode of the mounting substrate, solder can be spread while wetting with a flow in which air is less likely to be mixed. As a result, the connection by solder between the end portion external electrode and the connection electrode of the mounting substrate is less likely to be inhibited by voids.

[0009] The above multilayer ceramic electronic component may further include a central external electrode provided along the main surface and the side surface at the central portion in the second axial direction of the ceramic element body, wherein the thickness on the main surface is larger than that of the base portion and smaller than that of the main surface protruding portion. In this multilayer ceramic electronic component, in a three-terminal type configuration, while effectively obtaining the above effects, a good connection via solder of the central external electrode to the connection electrode of the mounting substrate can be obtained.

[0010] To achieve the above object, a circuit board according to one embodiment of the present invention includes a multilayer ceramic electronic component and a mounting substrate having connection electrodes. The above multilayer ceramic electronic component includes a ceramic element body and end portion external electrodes. The above ceramic element body has a main surface, an end surface, and a side surface perpendicular to a first axis, a second axis, and a third axis orthogonal to each other, a top portion connecting the main surface, the end surface, and the side surface, and a plurality of internal electrodes laminated in the first axis direction. The above end portion external electrode has a corner portion located on the top portion, a base portion covering the end surface and extending from the end surface to the main surface and the side surface, and a protruding portion protruding from the base portion, and is connected to the connection electrode of the mounting substrate via solder. The above protruding portion is an L-shaped main surface protruding portion located on the main surface and extending in the second axis direction and the third axis direction from the corner portion and a side surface protrusion extending in the first axial direction from the main surface protrusion along the side surface and includes.

Advantages of the Invention

[0011] An object of the present invention is to provide a multilayer ceramic electronic component and a circuit board in which voids are less likely to occur in solder during mounting.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 5C

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 8C

Figure 8D

Figure 8E

Figure 8F

Figure 9A

Figure 9B

Figure 9C

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are appropriately shown. The X-axis, Y-axis, and Z-axis are common throughout the figures.

[0014] [Basic Configuration of Multilayer Ceramic Capacitor 10] FIGS. 1 to 3 are views showing a multilayer ceramic capacitor 10 according to an embodiment of the present invention. FIG. 1 is a perspective view of the multilayer ceramic capacitor 10. FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1 of the multilayer ceramic capacitor 10. FIG. 3 is a cross-sectional view taken along line B-B' of FIG. 1 of the multilayer ceramic capacitor 10.

[0015] The multilayer ceramic capacitor 10 includes a ceramic body 11, a first end external electrode 13a, and a second end external electrode 13b. The outer surface of the ceramic body 11 has first and second end faces E1, E2 perpendicular to the X-axis, first and second side faces S1, S2 perpendicular to the Y-axis, and first and second main faces M1, M2 perpendicular to the Z-axis.

[0016] The ceramic body 11 is substantially rectangular parallelepiped-shaped and has eight tops 11a (see FIG. 7 etc.). That is, the tops 11a of the ceramic body 11 connect the end faces E1, E2, the side faces S1, S2, and the main faces M1, M2. The ceramic body 11 is chamfered, and it is preferable that each top 11a is composed of a rounded curved surface.

[0017] In the multilayer ceramic capacitor 10, the first end external electrode 13a covers the first end face E1 of the ceramic element body 11, and the second end external electrode 13b covers the second end face E2 of the ceramic element body 11. The end external electrodes 13a and 13b face each other in the X-axis direction with the ceramic element body 11 interposed therebetween and function as terminals of the multilayer ceramic capacitor 10.

[0018] The end external electrodes 13a and 13b respectively extend inward in the X-axis direction along the main surfaces M1 and M2 and the side surfaces S1 and S2 from the end faces E1 and E2 of the ceramic element body 11. As a result, in the end external electrodes 13a and 13b, both the cross section parallel to the X-Z plane shown in FIG. 2 and the cross section parallel to the X-Y plane are U-shaped.

[0019] The first end external electrode 13a covers the four top portions 11a on the first end face E1 side of the ceramic element body 11, and the second end external electrode 13b covers the four top portions 11a on the second end face E2 side of the ceramic element body 11. That is, the end external electrodes 13a and 13b each include four corner portions K located on the top portion 11a of the ceramic element body 11.

[0020] The end external electrodes 13a and 13b are formed of a material having high conductivity. Specifically, the end external electrodes 13a and 13b can be formed of a metal or an alloy mainly composed of at least one element such as Ni (nickel), Cu (copper), Pd (palladium), Ag (silver), and Sn (tin).

[0021] The end external electrodes 13a and 13b can be composed of, for example, an underlayer formed by baking a conductive metal paste and a plating layer formed by a wet plating method on the underlayer. As an example, the underlayer can be mainly composed of any one of Ni, Cu, Pd, and Ag. Further, the plating layer can be formed in a single-layer or multi-layer structure mainly composed of any one of Ni, Cu, Sn, Pd, and Ag.

[0022] The ceramic body 11 is formed of a dielectric ceramic. The ceramic body 11 has a plurality of first internal electrodes 12a and a plurality of second internal electrodes 12b covered with the dielectric ceramic. The plurality of internal electrodes 12a and 12b are both in the form of sheets extending along the X-Y plane and are alternately arranged along the Z-axis direction.

[0023] In the ceramic body 11, an opposing region is formed where the internal electrodes 12a and 12b face each other in the Z-axis direction with a ceramic layer interposed therebetween. The first internal electrode 12a is drawn out from the opposing region to the first end face E1 and is connected to the first end external electrode 13a. The second internal electrode 12b is drawn out from the opposing region to the second end face E2 and is connected to the second end external electrode 13b.

[0024] With such a configuration, in the multilayer ceramic capacitor 10, when a voltage is applied between the first end external electrode 13a and the second end external electrode 13b, a voltage is applied to the plurality of ceramic layers in the opposing region of the internal electrodes 12a and 12b. As a result, in the multilayer ceramic capacitor 10, charges corresponding to the voltage between the end external electrodes 13a and 13b are stored.

[0025] In the ceramic body 11, a high-permittivity dielectric ceramic is used to increase the capacitance of each ceramic layer between the internal electrodes 12a and 12b. The dielectric ceramic can be mainly composed of, for example, a ceramic material having a perovskite structure represented by the general formula ABO3. Note that the perovskite structure may contain ABO 3-α deviating from the stoichiometric composition. Examples of the ceramic material having a perovskite structure include materials containing barium (Ba) and titanium (Ti), typified by barium titanate (BaTiO3). Specifically, for example, Ba 1-x-y Ca x Sr y Ti 1-z Zr z O3 (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1) can be mentioned.

[0026] The dielectric ceramics may have a composition system such as strontium titanate (SrTiO3), calcium titanate (CaTiO3), magnesium titanate (MgTiO3), calcium zirconate (CaZrO3), calcium zirconium titanate (Ca(Zr,Ti)O3), barium zirconate (BaZrO3), titanium oxide (TiO2), etc.

[0027] [Detailed Configuration of End External Electrodes 13a and 13b] In the multilayer ceramic capacitor 10, the end external electrodes 13a and 13b each have a base portion 131 and a protruding portion 132. The base portion 131 is formed substantially flat along the surface of the ceramic element body 11. The protruding portion 132 is formed thicker than the base portion 131 and protrudes in the thickness direction from the base portion 131.

[0028] More specifically, the base portion 131 of each end external electrode 13a and 13b covers the end faces E1 and E2 of the ceramic element body 11 and extends from the end faces E1 and E2 to the main faces M1, M2 and the side faces S1, S2 respectively. Also, the protruding portion 132 of each end external electrode 13a and 13b constitutes a corner portion K located on each top portion 11a of the ceramic element body 11.

[0029] In each end external electrode 13a and 13b, the protruding portion 132 is provided in two locations, one on the side of the first side face S1 and the other on the side of the second side face S2. That is, the four protruding portions 132 provided on the end external electrodes 13a and 13b collectively cover two top portions 11a arranged in the Z-axis direction in the ceramic element body 11 and the ridge portion connecting them in the Z-axis direction.

[0030] The protruding portion 132 includes a main face protruding portion 132m located on the main faces M1 and M2, a side face protruding portion 132s located on the side faces S1 and S2, and an end face protruding portion 132e located on the end faces E1 and E2. The main face protruding portion 132m protrudes in the Z-axis direction, the side face protruding portion 132s protrudes in the Y-axis direction, and the end face protruding portion 132e protrudes in the X-axis direction.

[0031] Each main surface protruding portion 132m extends along the X-axis direction and the Y-axis direction respectively from the corner K, and has an L-shaped planar shape along the X-Y plane. Note that the planar shape of each main surface protruding portion 132m is considered to be L-shaped as long as it follows the L-shaped contour of the corner including the top 11a on the main surfaces M1 and M2, even if its appearance is different from the strict "L" font.

[0032] The side surface protruding portions 132s and the end surface protruding portions 132e extend along the Z-axis direction along the side surfaces S1, S2 and the end surfaces E1, E2 respectively, and constitute four ridge portions extending in the Z-axis direction of the end portion external electrodes 13a, 13b. The side surface protruding portions 132s and the end surface protruding portions 132e connect a pair of main surface protruding portions 132m facing each other in the Z-axis direction along the side surfaces S1, S2 and the end surfaces E1, E2 respectively.

[0033] That is, each side surface protruding portion 132s is provided continuously from the corresponding main surface protruding portion 132m, and the dimension in the X-axis direction is substantially equal to that of the corresponding main surface protruding portion 132m. Similarly, each end surface protruding portion 132e is provided continuously from the corresponding main surface protruding portion 132m, and the dimension in the Y-axis direction is substantially equal to that of the corresponding main surface protruding portion 132m.

[0034] FIG. 4A is a side view showing the manufacturing process of the circuit board 100 using the multilayer ceramic capacitor 10. The circuit board 100 has a mounting board 110 on which the multilayer ceramic capacitor 10 is mounted via the solder H. The mounting board 110 has a base material 111 extending along the X-Y plane and a connection electrode 112 provided on the base material 111.

[0035] In the mounting board 110, two connection electrodes 112 corresponding to the end portion external electrodes 13a, 13b of the multilayer ceramic capacitor 10 are provided, and solder H is disposed on each connection electrode 112 respectively. The multilayer ceramic capacitor 10 is placed on the mounting board 110 with the second main surface M2 of the ceramic element 11 facing the mounting board 110 and the positions of the end portion external electrodes 13a, 13b aligned with the positions on the connection electrodes 112.

[0036] By heating the mounting substrate 110 on which the multilayer ceramic capacitor 10 is placed in a reflow furnace or the like, the solder H on the connection electrode 112 is melted. As a result, the molten solder H spreads along the surfaces of the connection electrode 112 of the mounting substrate 110 and the end external electrodes 13a and 13b of the multilayer ceramic capacitor 10.

[0037] Specifically, the solder H spreads between the connection electrode 112 and the end external electrodes 13a and 13b, and further spreads upward in the Z-axis direction on the end external electrodes 13a and 13b. Then, by returning the solder H to room temperature and solidifying it, as shown in FIG. 4B, a circuit board 100 in which the multilayer ceramic capacitor 10 is connected to the mounting substrate 110 via the solder H is obtained.

[0038] In the circuit board 100, if voids exist in the solder H, the connection strength between the multilayer ceramic capacitor 10 and the mounting substrate 110 decreases and the connection resistance increases. Also, in the solder H with voids, cracks are likely to occur starting from the voids, and connection failures between the multilayer ceramic capacitor 10 and the mounting substrate 110 are likely to occur.

[0039] Furthermore, in the solder H, the thermal resistance increases due to the presence of voids. For this reason, in the multilayer ceramic capacitor 10, if voids exist in the solder H, the heat dissipation becomes insufficient, and the temperature may rise excessively during use. As a result, in the multilayer ceramic capacitor 10, problems such as function degradation and damage are likely to occur.

[0040] On the other hand, in the multilayer ceramic capacitor 10, due to the action of the protruding portions 132 of the end external electrodes 13a and 13b, air is less likely to be mixed in during the process in which the molten solder H spreads on the end external electrodes 13a and 13b. As a result, in the circuit board 100 using the multilayer ceramic capacitor 10, voids are less likely to occur in the solder H.

[0041] Figs. 5A to 5C schematically show the flow when the molten solder H spreads over the end external electrodes 13a and 13b using arrows. In the end external electrodes 13a and 13b, the solder H spreads starting from the main surface protruding portion 132m that protrudes downward in the Z-axis direction toward the connection electrode 112 on the second main surface M2 that constitutes the bottom surface of the multilayer ceramic capacitor 10.

[0042] By providing the main surface protruding portion 132m as a starting point for the spread of the solder H, a predetermined flow can be formed in the solder H that spreads over the end external electrodes 13a and 13b. Thereby, it is possible to prevent the entrainment of air that is likely to occur when the solder H spreads simultaneously from various unspecified positions on the end external electrodes 13a and 13b.

[0043] Fig. 5A shows the multilayer ceramic capacitor 10 from the side of the second main surface M2 that constitutes the bottom surface facing the mounting substrate 110. In the regions on the main surface M2 of each end external electrode 13a and 13b, the solder H spreads from the main surface protruding portions 132m on both sides in the Y-axis direction toward the inside in the X-axis and Y-axis directions on the base portion 131.

[0044] At this time, in the regions on the second main surface M2 of the end external electrodes 13a and 13b, L-shaped main surface protruding portions 132m are arranged at intervals at the four corners in the X-axis and Y-axis directions, respectively. Each main surface protruding portion 132m formed of a dense metal is easy to heat up and is easy to store heat by sufficiently contacting the solder H, so it quickly melts the solder H and becomes a starting point for spreading. For this reason, in the regions on the second main surface M2 of the end external electrodes 13a and 13b, a flow of the solder H toward the outside in the X-axis and Y-axis directions is less likely to occur. For this reason, the solder H spreads smoothly on the end external electrodes 13a and 13b without taking in air.

[0045] In this way, in the circuit board 100, voids are less likely to occur in the portion sandwiched between the end external electrodes 13a and 13b and the connection electrode 112, which most greatly affects the connection state between the multilayer ceramic capacitor 10 and the mounting substrate 110 in the solder H. Thereby, it is possible to effectively prevent a decrease in connection reliability and heat dissipation due to the generation of voids in the solder H.

[0046] In the end external electrodes 13a and 13b, by making the length of the portion extending in the X-axis direction in the L-shaped main surface protruding portion 132m larger than the length of the portion along the Y-axis, it becomes easier to control the spread of the solder H in the Y-axis direction. Further, by making the length of the portion extending in the Y-axis direction in the L-shaped main surface protruding portion 132m larger than the length of the portion along the X-axis, it becomes easier to control the spread of the solder H in the X-axis direction.

[0047] FIG. 5B shows the multilayer ceramic capacitor 10 from the second side surface S2 side. In the regions on the side surfaces S1 and S2 of each end external electrode 13a and 13b, the solder H wets upward in the Z-axis direction along the side surface protruding portion 132s from the main surface protruding portions 132m on both sides in the Y-axis direction and wets the inner base portion 131 in the X-axis direction.

[0048] FIG. 5C shows the multilayer ceramic capacitor 10 from the first end surface E1 side. In the regions on the end surfaces E1 and E2 of each end external electrode 13a and 13b, the solder H wets upward in the Z-axis direction along the end surface protruding portion 132e from the main surface protruding portions 132m on both sides in the Y-axis direction and wets the inner base portion 131 in the Y-axis direction.

[0049] In this way, in any region on the side surfaces S1 and S2 and the end surfaces E1 and E2 of the end external electrodes 13a and 13b, a predetermined flow can be formed in the solder H. As a result, voids are less likely to be formed in the solder H that has wet around the end external electrodes 13a and 13b, so that a decrease in connection reliability and heat dissipation performance can be more effectively prevented.

[0050] Note that the shape of the end external electrodes 13a and 13b can be appropriately determined so as to form an appropriate flow of the solder H.

[0051] For example, regarding the portions on the main surfaces M1 and M2 of the end external electrodes 13a and 13b, the thickness of the base portion 131 is preferably 10 μm or more and 110 μm or less, and can be 50 μm as an example. Also, the thickness of the main surface protruding portion 132m is preferably 13 μm or more and 160 μm or less, and can be 80 μm as an example. Further, the protruding amount of the main surface protruding portion 132m from the base portion 131 is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less.

[0052] Also, regarding the portions on the side surfaces S1 and S2 of the end external electrodes 13a and 13b, the thickness of the base portion 131 is preferably 10 μm or more and 110 μm or less, and can be 50 μm as an example. Also, the thickness of the side surface protruding portion 132s is preferably 13 μm or more and 160 μm or less, and can be 80 μm as an example. Further, the protruding amount of the side surface protruding portion 132s from the base portion 131 is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less.

[0053] Furthermore, regarding the portions on the end surfaces E1 and E2 of the end external electrodes 13a and 13b, the thickness of the base portion 131 is preferably 15 μm or more and 125 μm or less, and can be 60 μm as an example. Also, the thickness of the end surface protruding portion 132e is preferably 18 μm or more and 175 μm or less, and can be 90 μm as an example. Further, the protruding amount of the end surface protruding portion 132e from the base portion 131 is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less.

[0054] Note that the thickness of each portion on each surface (main surfaces M1 and M2, side surfaces S1 and S2, and end surfaces E1 and E2) of the end external electrodes 13a and 13b can be measured at the position that is the center of gravity of the two-dimensional region occupied by each portion when viewed from a direction perpendicular to each surface.

[0055] In addition, in the main surface protrusion 132m of the multilayer ceramic capacitor 10 with a dimension in the X-axis direction of 1370 μm and a dimension in the Y-axis direction of 800 μm, the dimension in the X-axis direction is preferably 100 μm or more and 250 μm or less, and the dimension in the Y-axis direction is preferably 50 μm or more and 250 μm or less.

[0056] [Manufacturing Method of Multilayer Ceramic Capacitor 10] FIG. 6 is a flowchart showing an example of the manufacturing method of the multilayer ceramic capacitor 10 according to the present embodiment. FIGS. 7 to 9C are diagrams showing the manufacturing process of the multilayer ceramic capacitor 10. Hereinafter, the manufacturing method of the multilayer ceramic capacitor 10 will be described with reference to FIGS. 6 to 9C as appropriate along FIG. 6.

[0057] (Step S01: Fabrication of Ceramic Body) In step S01, an unfired ceramic body 11 is fabricated. The unfired ceramic body 11 is obtained by laminating and thermocompression bonding a plurality of ceramic sheets in the Z-axis direction. By previously printing a conductive metal paste with a predetermined pattern on the ceramic sheet, the internal electrodes 12a and 12b can be arranged.

[0058] The ceramic sheet is an unfired dielectric green sheet formed by shaping a ceramic slurry into a sheet shape. The ceramic sheet is formed into a sheet shape using, for example, a roll coater or a doctor blade. The components of the ceramic slurry are adjusted so as to obtain a ceramic body 11 having a predetermined composition.

[0059] (Step S02: Firing) In step S02, the unfired ceramic body 11 obtained in step S01 is fired. As a result, the ceramic body 11 is sintered, and the ceramic body 11 shown in FIG. 7 is obtained. The firing of the ceramic body 11 can be performed, for example, in a reducing atmosphere or in an atmosphere with a low oxygen partial pressure. The firing conditions of the ceramic body 11 can be determined as appropriate.

[0060] (Step S03: Formation of End External Electrodes) In step S03, end external electrodes 13a and 13b are formed on the ceramic element 11 obtained in step 02. Thereby, the multilayer ceramic capacitor 10 shown in FIGS. 1 to 3 is completed. Step S03 includes four steps: step S31, step S32, step S33, and step S34.

[0061] (Step S31: Formation of First Underlayer) In step S31, a first underlayer L1 that constitutes the underlayer of the end external electrodes 13a and 13b is formed on the ceramic element 11. The first underlayer L1 is provided at a position corresponding to the protruding portions 132 of the end external electrodes 13a and 13b. For the formation of the first underlayer L1 in step S31, a conductive metal paste P is used.

[0062] FIGS. 8A to 8F show the process of forming the first underlayer L1 on the ceramic element 11 in step S31. First, as shown in FIG. 8A, the second side surface S2 of the ceramic element 11 is immersed in the conductive metal paste P arranged at two locations with a gap therebetween. As a result, the conductive metal paste P adheres to the second side surface S2 of the ceramic element 11, and an intermediate film L1a as a part of the first underlayer L1 is formed as shown in FIG. 8B.

[0063] Then, similarly, as shown in FIG. 8C, by immersing the first side surface S1 of the ceramic element 11 in the conductive metal paste P, an intermediate film L1a as a part of the first underlayer L1 is also formed on the first side surface S1 of the ceramic element 11. As a result, intermediate films L1a are formed at four locations on the surface of the ceramic element 11.

[0064] Next, as shown in FIG. 8D, the first end surface E1 of the ceramic element 11 is immersed in the conductive metal paste P arranged at two locations with a gap therebetween. As a result, the conductive metal paste P adheres to the first end surface E1 of the ceramic element 11, and together with the conductive metal paste P constituting the intermediate film L1a, an L-shaped first underlayer L1 is formed as shown in FIG. 8E.

[0065] Then, similarly, as shown in FIG. 8F, by immersing the second end face E2 of the ceramic body 11 in the conductive metal paste P, an L-shaped first underlayer L1 is also formed on the second end face E2 side. As a result, the first underlayer L1 is formed at four locations on the surface of the ceramic body 11.

[0066] Note that the conditions of step S31 can be determined as appropriate. For example, the viscosity of the conductive metal paste P can be 320 PS. The immersion time of the ceramic body 11 in the conductive metal paste P can be 1.5 seconds. Further, the first underlayer L1 after immersion can be dried under predetermined conditions.

[0067] (Step S32: Formation of second underlayer) In step S32, a second underlayer L2 that constitutes the underlayer of the end portion external electrodes 13a and 13b together with the first underlayer L1 is formed on the ceramic body 11 on which the first underlayer L1 is formed. The second underlayer L2 is provided over the entire end portion external electrodes 13a and 13b. The conductive metal paste P is also used for forming the second underlayer L2 in step S32.

[0068] FIGS. 9A to 9C show the process of forming the second underlayer L2 on the ceramic body 11 in step S32. First, as shown in FIG. 9A, the ceramic body 11 is immersed in the conductive metal paste P from the first end face E1 side to a position where the first underlayer L1 sinks, and the conductive metal paste P is adhered onto the ceramic body 11 and the first underlayer L1.

[0069] Thereby, as shown in FIG. 9B, a second underlayer L2 that covers the first end face E1 side of the ceramic body 11 from above the first underlayer L1 is formed. In the underlayers L1 and L2 formed on the ceramic body 11, only the portion of the second underlayer L2 corresponds to the base portion 131, and the portion where the underlayers L1 and L2 overlap corresponds to the protruding portion 132.

[0070] Then, similarly, as shown in FIG. 9C, by immersing the ceramic body 11 in the conductive metal paste P from the second end face E2 side to the position where the first base layer L1 sinks, a second base layer L2 is also formed on the second end face E2 side in the same manner as on the first end face E1 side. As a result, the outer shapes of the base portions 131 and the protruding portions 132 of the end external electrodes 13a and 13b are obtained.

[0071] Note that the conditions of step S32 can be determined as appropriate. For example, the viscosity of the conductive metal paste P can be 320 PS. The immersion time of the ceramic body 11 in the conductive metal paste P can be 1.5 seconds. Also, the second base layer L2 after immersion can be dried under predetermined conditions.

[0072] (Step S33: Baking) In step S33, the base layers L1 and L2 formed on the ceramic body 11 are baked by heat treatment. Note that by performing steps S31 and S32 before step S02, the firing of the ceramic body 11 in step S02 and the baking of the base layers L1 and L2 in step S33 can also be performed in a single heat treatment.

[0073] (Step S34: Plating layer formation) In step S34, a plating layer is formed on the base layers L1 and L2 baked on the ceramic body 11 by wet plating. As a result, the end external electrodes 13a and 13b are completed. Since a plating layer of uniform thickness is formed by wet plating, the shapes of the base layers L1 and L2 as described above are maintained for the end external electrodes 13a and 13b.

[0074] (Modification) The manufacturing method described above can be variously modified as long as the configuration of the multilayer ceramic capacitor 10 of the present embodiment is obtained. For example, the method of forming the end external electrodes 13a and 13b is not limited to the method of forming the first and second base layers L1 and L2 as described above as long as the base portions 131 and the protruding portions 132 can be formed.

[0075] [Other Embodiments] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited only to the above-described embodiments, and it goes without saying that various modifications can be made.

[0076] For example, the protruding portions 132 of the end external electrodes 13a and 13b only need to include at least the main surface protruding portions 132m, and may not include at least one of the side surface protruding portions 132s and the end surface protruding portions 132e. Also in this case, it is possible to suppress a decrease in connection reliability and heat dissipation due to the generation of voids in the solder H. Further, the protruding portions 132 are preferably provided at all four corners in the X-axis and Y-axis directions, but may be provided at at least one corner.

[0077] Further, the multilayer ceramic capacitor according to the present embodiment is not limited to the two-terminal type, and can also be configured as a three-terminal type. FIGS. 10 and 11 show a three-terminal multilayer ceramic capacitor 10a. The multilayer ceramic capacitor 10a is provided with a central external electrode 14 provided at the central portion in the X-axis direction of the ceramic element 11.

[0078] The central external electrode 14 is provided over the entire circumference along the main surfaces M1 and M2 and the side surfaces S1 and S2 of the ceramic element 11. In the multilayer ceramic capacitor 10a, all of the first internal electrodes 12a are connected to the end external electrodes 13a and 13b, and all of the second internal electrodes 12b are connected to the central external electrode 14.

[0079] In the multilayer ceramic capacitor 10a, it is preferable that the thickness of the central external electrode 14 on the main surfaces M1 and M2 is smaller than the thickness of the main surface protruding portions 132m on the main surfaces M1 and M2. Thereby, the formation of the flow of the solder H starting from the main surface protruding portions 132m as described above during mounting is less likely to be hindered by the presence of the central external electrode 14.

[0080] In addition, in the multilayer ceramic capacitor 10a, it is preferable that the thickness on the main surfaces M1 and M2 of the central external electrode 14 is greater than the thickness on the main surfaces M1 and M2 of the base portion 131. Thereby, in the multilayer ceramic capacitor 10a, the central external electrode 14 can be more reliably brought into contact with the solder H on the connection electrode 112 of the mounting substrate 110 during mounting.

[0081] Note that the three-terminal type multilayer ceramic capacitor 10a is not limited to a configuration in which the central external electrode 14 is provided over the entire circumference along the main surfaces M1 and M2 and the side surfaces S1 and S2 of the ceramic element 11. For example, in the multilayer ceramic capacitor 10a, the central external electrodes 14 may be spaced apart in the Y-axis direction on the main surfaces M1 and M2 of the ceramic element 11.

[0082] Furthermore, the present invention is applicable not only to multilayer ceramic capacitors but also to all multilayer ceramic electronic components having end external electrodes. Examples of the multilayer ceramic electronic components to which the present invention is applicable include, in addition to multilayer ceramic capacitors, chip varistors, chip thermistors, multilayer inductors, and the like.

Explanation of Reference Numerals

[0083] 10... Multilayer ceramic capacitor 11... Ceramic element 11a... Top 12a, 12b... Internal electrodes 13a, 13b... End external electrodes 131... Base portion 132... Protrusion 132m... Main surface protrusion 132s... Side surface protrusion 132e... End face protrusion M1, M2... Main surfaces S1, S2... Side surfaces E1, E2... End faces K... Corner

Claims

1. A ceramic element having a main surface, an end surface, and a side surface perpendicular to a first axis, a second axis, and a third axis that are orthogonal to each other, a top portion connecting the main surface, the end surface, and the side surface, and a plurality of internal electrodes laminated in the first axis direction; An end external electrode having a corner portion located on the top portion, a base portion covering the end surface and extending from the end surface to the main surface and the side surface, and a protruding portion protruding in the thickness direction from the base portion; Comprising: The protruding portion includes an L-shaped main surface protruding portion located on the main surface and extending from the corner portion in the second axis direction and the third axis direction, and a side surface protruding portion extending from the main surface protruding portion in the first axis direction along the side surface. A multilayer ceramic electronic component.

2. The multilayer ceramic electronic component according to Claim 1, wherein The amount of protrusion of the main surface protruding portion from the base portion is 3 μm or more and 50 μm or less. A multilayer ceramic electronic component.

3. The multilayer ceramic electronic component according to Claim 1 or 2, wherein The amount of protrusion of the main surface protruding portion from the base portion is 5 μm or more and 30 μm or less. A multilayer ceramic electronic component.

4. The multilayer ceramic electronic component according to any one of Claims 1 to 3, wherein The protruding portion further includes an end surface protruding portion extending from the main surface protruding portion in the first axis direction along the end surface. A multilayer ceramic electronic component.

5. The multilayer ceramic electronic component according to Claim 4, wherein The amount of protrusion of the end surface protruding portion from the base portion is 3 μm or more and 50 μm or less. A multilayer ceramic electronic component.

6. The multilayer ceramic electronic component according to any one of Claims 1 to 5, wherein The amount of protrusion of the side surface protruding portion from the base portion is 3 μm or more and 50 μm or less. A multilayer ceramic electronic component.

7. The multilayer ceramic electronic component according to any one of Claims 1 to 6, wherein A central external electrode is further provided along the main surface and the side surface at a central portion of the ceramic element in the second axis direction, and the thickness on the main surface is larger than that of the base portion and smaller than that of the main surface protruding portion. A multilayer ceramic electronic component.

8. Comprising a multilayer ceramic electronic component and a mounting substrate having connection electrodes, The multilayer ceramic electronic component is A ceramic element having main surfaces, end surfaces, and side surfaces perpendicular to a first axis, a second axis, and a third axis that are mutually orthogonal, respectively, a top portion connecting the main surfaces, the end surfaces, and the side surfaces, and a plurality of internal electrodes laminated in the first axis direction. An end portion external electrode having a corner portion located on the top portion, a base portion covering the end surface and extending from the end surface to the main surface and the side surface, and a protruding portion protruding in the thickness direction from the base portion, and being connected to the connection electrode of the mounting substrate via solder. Including The protruding portion includes an L-shaped main surface protruding portion located on the main surface and extending in the second axis direction and the third axis direction from the corner portion, and a side surface protruding portion extending in the first axis direction from the main surface protruding portion along the side surface. Circuit board.

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