Multilayer ceramic electronic component and manufacturing method for the same

Abstract

To provide a multilayer ceramic electronic component and a manufacturing method for the same with which it is possible to prevent defects and heighten reliability.SOLUTION: A multilayer ceramic electronic component comprises: a ceramic element that includes a protective part having an end surface facing in a first direction, a plurality of peripheral surfaces concatenated to the end surface and extending along the first direction, and a ridge part having a recess extending along the first direction and connecting between the plurality of peripheral surfaces, and a function part which is located inward of the protective part; and an external electrode that includes an underlying film that covers the end surface, and a plating film which is formed on the underlying film. The function part includes a plurality of internal electrodes which is laminated in a second direction orthogonal to the first direction, and the ridge part is located outward of the edges of the plurality of internal electrodes in a third direction orthogonal to the first and second directions, when seen from the second direction.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Multilayer ceramic electronic components such as multilayer ceramic capacitors include a ceramic body in which internal electrodes are laminated and external electrodes that cover each end face of the ceramic body. The external electrodes typically continuously cover from the end face to a part of a plurality of peripheral faces connected to the end face.

[0003] On the other hand, since the electrode material and the ceramic material constituting the external electrode have different linear expansion coefficients, stress accumulates in the external electrode due to heat treatment or heat generation after mounting, and defects such as cracks in the ceramic body or the external electrode may occur.

[0004] Patent Document 1 discloses a ceramic electronic component having a fired electrode layer having first to fifth portions that are at least partially separated from each other from the viewpoint of preventing crack generation.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the configuration described in Patent Document 1, it is difficult to control the separation width of the first to fifth portions of the fired electrode layer, and it is easy for the Cu plating film covering it to be separated. When the Cu plating film is separated, insulation failure or the like may occur in the multilayer ceramic capacitor after the plating process, and it becomes difficult to ensure reliability.

[0007] In view of the above circumstances, an object of the present invention is to provide a multilayer ceramic electronic component capable of preventing defects and enhancing reliability, and a method for manufacturing the same.

Means for Solving the Problems

[0008] To achieve the above object, a multilayer ceramic electronic component according to one embodiment of the present invention includes a ceramic body and external electrodes. The ceramic body has a protection part and a functional part. The protection part includes an end face facing in a first direction, a plurality of peripheral surfaces connected to the end face and extending in the first direction, and a ridge part having a concave part extending along the first direction and connecting between the plurality of peripheral surfaces. The functional part is disposed inside the protection part. The base film includes a first coating part formed on the end face, a plurality of second coating parts respectively formed on the plurality of peripheral surfaces, and a third coating part formed on the concave part and spaced apart from at least one of the plurality of second coating parts at the edge part. The plating film continuously covers the first coating part, the plurality of second coating parts, and the third coating part.

[0009] Since the base film containing the electrode material and the ceramic body have different linear expansion coefficients, stresses are applied in different directions at each second coating part by heating and cooling. In the base film of the external electrode having the above configuration, the second coating parts on the plurality of peripheral surfaces and the third coating part on the concave part are separated from each other. Therefore, the influence of stress is cut off in the discontinuous region of the base film, and it becomes difficult for stress to accumulate in the external electrode and the ceramic body. Thereby, damage to the ceramic body due to the stress is prevented. Further, since the ceramic body has a concave part adjacent to the edge part, it becomes easier for the electrode material of the base film to remain in the concave part, and the discontinuous region of the base film can be minimized. As a result, the plating film is continuously formed also on the discontinuous region of the base film, and breakage of the entire external electrode can be prevented.

[0010] The functional part has a plurality of internal electrodes laminated in a second direction orthogonal to the first direction. The positions of the ends of the plurality of internal electrodes in a third direction orthogonal to the first direction and the second direction may be aligned with each other within a range of 0.5 μm in the third direction. Thereby, a sufficient proportion of the functional parts in the ceramic element can be ensured. Therefore, a high-performance multilayer ceramic electronic component can be obtained without increasing the size.

[0011] In a method for manufacturing a multilayer ceramic electronic component according to another embodiment of the present invention, a ceramic element having a protective part including an end face facing in a first direction, a plurality of peripheral faces connected to the end face and extending in the first direction, and a ridge part having a recess extending along the first direction and connecting between the plurality of peripheral faces, and a functional part disposed inside the protective part is produced. A conductive base film including a first coating part formed on the end face, a plurality of second coating parts respectively formed on the plurality of peripheral faces, and a third coating part formed on the recess and separated from at least one of the plurality of second coating parts at the edge part is formed. A plating film that continuously covers the first coating part, the plurality of second coating parts, and the third coating part is formed.

[0012] In the step of producing the ceramic element, a ceramic laminated chip in which a plurality of internal electrodes are laminated in a second direction orthogonal to the first direction and the plurality of internal electrodes are exposed from a side face facing in a third direction orthogonal to the first direction and the second direction is produced, a first side margin part laminated on the side face and a second side margin part laminated on the first side margin part and having a higher thermal shrinkage rate than the first side margin part are formed, the ceramic laminated chip, the first side margin part, and the second side margin part may be fired. In this configuration, by being fired, the second side margin portion shrinks more than the first side margin portion. As a result, the outer edge of the second side margin portion is formed inward of the outer edge of the first side margin portion, and recesses are formed in these outer edges. Therefore, the ceramic green body having the above configuration can be easily manufactured.

[0013] The first side margin portion is formed by attaching a first ceramic sheet onto the side surface. The second side margin portion may be formed by attaching a second ceramic sheet having a higher thermal shrinkage rate than the first ceramic sheet onto the first ceramic sheet. Thereby, the first side margin portion and the second side margin portion can be easily formed.

Advantages of the Invention

[0014] As described above, according to the present invention, it is possible to provide a multilayer ceramic electronic component capable of preventing defects and enhancing reliability, and a method for manufacturing the same.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

[0016] 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.

[0017] [Overall Configuration of Multilayer Ceramic Capacitor 10] Figs. 1 to 4 are views showing a multilayer ceramic capacitor 10 according to a first embodiment of the present invention. Fig. 1 is a perspective view of the multilayer ceramic capacitor 10. Fig. 2 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line A-A' of Fig. 1. Fig. 3 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line B-B' of Fig. 1. Fig. 4 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line C-C' of Fig. 1.

[0018] The multilayer ceramic capacitor 10 includes a ceramic body 11 and two external electrodes 14. The two external electrodes 14 are respectively formed on the surfaces of the ceramic body 11.

[0019] The ceramic body 11 has a capacitance forming portion 16 and a protective portion 17. The protective portion 17 constitutes the peripheral portion of the ceramic body 11 and has two end faces 11a facing the X-axis direction, two side faces 11b facing the Y-axis direction, two main faces 11c facing the Z-axis direction, and ridge portions 11e connecting between the main face 11c and the side face 11b. The side face 11b and the main face 11c constitute a plurality of peripheral surfaces in the present embodiment. The end faces 11a, the side faces 11b, and the main faces 11c are, for example, composed of substantially flat surfaces, but may be rounded.

[0020] Specifically, the protective portion 17 has a cover portion 18 located outside the capacitance forming portion 16 in the Z-axis direction, a side margin portion 19 located outside the capacitance forming portion 16 in the Y-axis direction, and an end margin portion 20 located outside the capacitance forming portion 16 in the X-axis direction.

[0021] The capacitance forming portion 16 is disposed inside the protective portion 17 and constitutes the functional portion in the present embodiment. In the capacitance forming portion 16, a plurality of first internal electrodes 12 and a plurality of second internal electrodes 13 are laminated in the Z-axis direction via a ceramic layer 15 (see FIG. 2). Both the internal electrodes 12 and 13 are in the form of sheets extending along the X-Y plane and are alternately arranged in the Z-axis direction.

[0022] The internal electrodes 12 and 13 are each formed of a good electrical conductor and function as the internal electrodes of the multilayer ceramic capacitor 10. As the good electrical conductor for forming the internal electrodes 12 and 13, for example, metals and alloys mainly composed of nickel (Ni), copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), etc. are used.

[0023] As shown in FIG. 2, the internal electrodes 12 and 13 are connected to an external electrode 14 covering the end face 11a. The first internal electrode 12 is drawn out to one of the end faces 11a of the ceramic body 11 and is connected to one external electrode 14. The second internal electrode 13 is drawn out to the other end face 11a and is connected to the other external electrode 14.

[0024] The ceramic layer 15 is formed of a dielectric ceramic. In the multilayer ceramic capacitor 10, a dielectric ceramic with a high dielectric constant is used to increase the capacitance of each ceramic layer 15 between the internal electrodes 12 and 13. Examples of the dielectric ceramic with a high dielectric constant include materials having a perovskite structure containing barium (Ba) and titanium (Ti), typified by barium titanate (BaTiO3).

[0025] In addition to the barium titanate-based dielectric ceramics, the dielectric ceramics may also be strontium titanate (SrTiO3)-based, calcium titanate (CaTiO3)-based, magnesium titanate (MgTiO3)-based, calcium zirconate (CaZrO3)-based, calcium zirconate titanate (Ca(Zr,Ti)O3)-based, barium zirconate (BaZrO3)-based, titanium dioxide (TiO2)-based, etc.

[0026] The protective part 17 is also formed of a dielectric ceramic. The material for forming the protective part 17 may be an insulating ceramic, but using a material with the same composition system as the ceramic layer 15 improves the manufacturing efficiency and suppresses the internal stress in the ceramic body 11.

[0027] The external electrode 14 includes a base film 21 formed to cover the end face 11a, and a plating film 22 formed on the base film 21. The base film 21 is composed of, for example, a baked film obtained by baking a conductive paste, a sputtered film, or the like. The plating film 22 is a film formed by electrolytic plating. Each film of the external electrode 14 is formed of a metal or alloy mainly composed of, for example, nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), or the like.

[0028] The base film 21 of the external electrode 14 includes an end face covering portion 25 formed on the end face 11a, a main face covering portion 26c formed on the main face 11c, a side face covering portion 26b formed on the side face 11b, and a recess covering portion 27 formed on a recess 23 to be described later. In the present embodiment, the end face covering portion 25 constitutes the first covering portion, the main face covering portion 26c and the side face covering portion 26b constitute a plurality of second covering portions, and the recess covering portion 27 constitutes the third covering portion, respectively.

[0029] In the present embodiment, the side face covering portion 26b and the main face covering portion 26c of the base film 21 are separated from the recess covering portion 27 at the ridge portion 11e, respectively, and the interrupted portions are also covered with the plating film 22. Hereinafter, the configuration near the ridge portion 11e will be described in detail.

[0030] [Detailed Configuration of the Multilayer Ceramic Capacitor 10] FIG. 5 is an enlarged view of FIG. 4 and shows the ridge portion 11e and the surrounding configuration. Although FIG. 5 shows one ridge portion 11e and the surrounding configuration, the same applies to the other ridge portions 11e and the surrounding configuration.

[0031] The ridge portion 11e has a recess 23 extending along the X-axis direction. At the outer edge of the recess 23, an edge portion 24 that forms a boundary between the main face 11c or the side face 11b and the recess 23 and protrudes outward is formed. A pair of edge portions 24 are formed with one recess 23 interposed therebetween.

[0032] The recess 23 is a portion that indents inward of the ceramic element 11 from a straight line Le connecting between the two edge portions 24 in a cross section cut in the Z-axis direction. Small steps or irregularities that do not protrude from the straight line Le may be formed in the recess 23.

[0033] As described above, the main surface covering portion 26c of the base film 21 is formed on the main surface 11c, and the side surface covering portion 26b of the base film 21 is formed on the side surface 11b. The recess covering portion 27 of the base film 21 is formed on the recess 23. The recess covering portion 27 is separated from at least one of the main surface covering portion 26c and the side surface covering portion 26b at the edge portion 24. In the present embodiment, the recess covering portion 27 is separated from both the main surface covering portion 26c and the side surface covering portion 26b.

[0034] In the present embodiment, the plating film 22 has a plurality of layer structures. The plating film 22 includes an intermediate film 28 formed on the base film 21 and a surface layer film 29 formed on the intermediate film 28. The intermediate film 28 and the surface layer film 29 continuously cover the entire end surface covering portion 25, main surface covering portion 26c, side surface covering portion 26b, and recess covering portion 27 of the base film 21. The metal materials constituting the intermediate film 28 and the surface layer film 29 may be the same or different. The metal material may be selected from, for example, copper, nickel, tin, or alloys thereof.

[0035] Since the base film 21 has the main surface covering portion 26c, the side surface covering portion 26b, and the recess covering portion 27 that are separated from each other, defects such as cracks in the ceramic element 11 caused by temperature changes can be prevented.

[0036] The electrode material constituting the base film 21 and the ceramic material constituting the ceramic element 11 have different linear expansion coefficients. As a result, when the base film 21 cools after baking or after heat generation during mounting, the base film 21 shrinks more than the ceramic element 11, and tensile stress is generated in the base film 21. On the other hand, compressive stress caused by the tensile stress is generated in the ceramic element 11.

[0037] For example, tensile stress directed inward in the Y-axis direction is generated in the main surface covering portion 26c of the base film 21. For example, tensile stress directed inward in the Z-axis direction is generated in the side surface covering portion 26b of the base film 21. As a result, tensile stress in different directions is generated in the base film 21 near the ridge portion 11e.

[0038] In this embodiment, the main surface covering portion 26c and the side surface covering portion 26b are separated. As a result, even when the above-mentioned tensile stress occurs, stress is not accumulated in the base film 21. Therefore, it is possible to prevent a large compressive stress from occurring in the ceramic element 11 and defects such as cracks from occurring in the ceramic element 11.

[0039] Furthermore, in this embodiment, a recess covering portion 27 is formed on the recess 23. The recess covering portion 27 can prevent the electrode material of the base film 21 from staying in the recess 23 and can minimize the separation width between the base films 21.

[0040] FIG. 6 is a cross-sectional view showing the configuration of the multilayer ceramic capacitor 10A according to the comparative example, and is an enlarged view showing the same part as in FIG. 5. The multilayer ceramic capacitor 10A is not provided with a recess in the protective portion 17A, and the side surface 11Ab and the main surface 11Ac of the ceramic element 11A are connected at the ridge portion 11Ae. The ridge portion 11Ae is formed of a convex curved surface on the outside of the ceramic element 11A.

[0041] When trying to separate the base film 21A of this ceramic element 11A at the ridge portion 11Ae, the main surface covering portion 26Ac and the side surface covering portion 26Ab that are adjacent to each other are separated. Since the ridge portion 11Ae is sharply curved at an angle close to a right angle, it is difficult to control these separation widths. As a result, the separation widths of the main surface covering portion 26Ac and the side surface covering portion 26Ab become large, and the ridge portion 11Ae is likely to protrude from between them.

[0042] When the plating film 22A is formed on this base film 21A, the plating film 22A cannot cover the ridge portion 11Ae and becomes discontinuous on the ridge portion 11Ae. Therefore, a gap is formed between the ridge portion 11Ae of the ceramic element 11A and the external electrode 14A. When moisture in the air enters from this gap, the multilayer ceramic capacitor 10A generates insulation failure, and it becomes difficult to ensure reliability.

[0043] On the other hand, in the present embodiment shown in FIG. 5, the concave portion covering portion 27 is formed by the electrode material remaining in the concave portion 23. As a result, the separation width between the main surface covering portion 26c or the side surface covering portion 26b of the base film 21 and the concave portion covering portion 27 is regulated, and the plating film 22 can continuously cover the entire base film 21. Thereby, the generation of a gap between the external electrode 14 and the ceramic element body 11 can be prevented, and insulation failure can be prevented. Therefore, the reliability of the multilayer ceramic capacitor 10 can be improved.

[0044] In addition, in the ceramic element body 11A according to the comparative example, as a method of reliably covering the ridge portion 11Ae with the external electrode 14A, there is a method of rounding the corners of the ridge portion 11Ae by barrel polishing or the like. However, when forming the side margin portion by attaching a ceramic sheet as described later, the ceramic sheet may be peeled off by performing barrel polishing, and defects are likely to occur in the side margin portion.

[0045] In the present embodiment, as will be described in the following manufacturing method, the shape of the ridge portion 11e can be optimized without performing barrel polishing, and defects such as peeling of the side margin portion 19 can be prevented. Thereby, the reliability of the multilayer ceramic capacitor 10 can be further improved.

[0046] [Manufacturing Method of Multilayer Ceramic Capacitor 10] FIG. 7 is a flowchart showing a manufacturing method of the multilayer ceramic capacitor 10. FIGS. 8 to 14 are diagrams schematically 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. 8 to 14 as appropriate along FIG. 7.

[0047] (Step S01: Fabrication of Ceramic Multilayer Chip C) In step S01, an unfired ceramic multilayer chip (multilayer chip) C is fabricated by laminating and cutting a ceramic sheet 101 and a ceramic sheet 102 for forming the capacitance forming portion 16 and a ceramic sheet 103 for forming the cover portion 18.

[0048] The ceramic sheets 101, 102, and 103 shown in FIG. 8 are configured as unfired dielectric green sheets containing a ceramic material made of dielectric ceramics, an organic binder, and other additives. An unfired first internal electrode 112 corresponding to the first internal electrode 12 is formed on the ceramic sheet 101. An unfired second internal electrode 113 corresponding to the second internal electrode 13 is formed on the ceramic sheet 102. No internal electrode is formed on the ceramic sheet 103.

[0049] Each of the internal electrodes 112 and 113 has a plurality of strip-shaped electrode patterns that cross a cutting line Lx parallel to the X-axis direction and extend along a cutting line Ly parallel to the Y-axis direction. These internal electrodes 112 and 113 are formed by applying a conductive paste to the ceramic sheets 101 and 102 by a printing method or the like.

[0050] As shown in FIG. 8, the ceramic sheets 101 and 102 are alternately laminated in the Z-axis direction. The laminate of the ceramic sheets 101 and 102 corresponds to the capacitance forming portion 16 and the end margin portion 20. The ceramic sheet 103 is laminated on the upper and lower surfaces in the Z-axis direction of the laminate of the ceramic sheets 101 and 102. The laminate of the ceramic sheet 103 corresponds to the cover portion 18. Note that the number of laminated ceramic sheets 101, 102, and 103 can be adjusted as appropriate.

[0051] Subsequently, the laminate of the ceramic sheets 101, 102, and 103 is pressure-bonded from the Z-axis direction and cut along the cutting lines Lx and Ly. Thereby, a laminated chip C shown in FIG. 9 is produced.

[0052] The laminated chip C has an unfired capacitance forming portion 116 in which unfired internal electrodes 112 and 113 are formed, an unfired cover portion 118, and an unfired end margin portion 120. A side surface Cb that is a cut surface corresponding to the cutting line Lx and an end surface Ca that is a cut surface corresponding to the cutting line Ly are formed on the laminated chip C. The ends of the unfired internal electrodes 112 and 113 are exposed from the side surface Cb.

[0053] (Step 02: Forming the side margin portion 119) In step S02, a side margin portion 119 is formed on the side surface Cb of the stacked chip C. Hereinafter, an example of the forming method will be shown.

[0054] First, as shown in FIG. 10, a stacked sheet S, which is a laminate of ceramic sheets, is disposed on a flat plate-shaped elastic member E, and the other side surface Cb of the stacked chip C held by a tape T on one side surface Cb is opposed to the stacked sheet S.

[0055] In this embodiment, the stacked sheet S has a stacked structure of a first ceramic sheet 104, a second ceramic sheet 105, and a third ceramic sheet 106 for forming a side margin. Each of the ceramic sheets 104, 105, 106 includes a ceramic material, an organic binder, and other additives, similar to the ceramic sheets 101, 102, 103.

[0056] The second ceramic sheet 105 has a higher thermal shrinkage rate than the first ceramic sheet 104. Further, the third ceramic sheet 106 has a higher thermal shrinkage rate than the second ceramic sheet 105. The thermal shrinkage rate can be adjusted by adjusting the amounts of the organic binder and additives.

[0057] Next, as shown in FIG. 11, the stacked sheet S is punched out at the side surface Cb of the stacked chip C, so that the stacked sheet S is attached to the side surface Cb. Specifically, the stacked chip C is strongly pressed against the stacked sheet S in the Y-axis direction. Thereby, the stacked chip C sinks deeply locally into the elastic member E together with the stacked sheet S. At this time, a shearing force acts on the stacked sheet S along the outer edge of the side surface Cb, and when this shearing force becomes equal to or greater than the shearing strength of the stacked sheet S, the stacked sheet S is punched out.

[0058] Then, as shown in FIG. 12, a part of the laminated sheet S that has sunk together with the laminated chip C is separated. As a result, a first side margin portion 119a laminated on the side surface Cb and a second side margin portion 119b laminated on the first side margin portion 119a are formed. Further, in the present embodiment, a third side margin portion 119c laminated on the second side margin portion 119b is formed. Thereby, an unfired side margin portion 119 including the first side margin portion 119a, the second side margin portion 119b, and the third side margin portion 119c is formed on the side surface Cb of the laminated chip C.

[0059] And similarly, a side margin portion 119 is formed on the other side surface Cb. Thereby, the unfired ceramic green body 111 shown in FIG. 13 is produced. At this stage, the concave portion 23 is not formed at the ridge portion 111e between the main surface 111c and the side surface 111b.

[0060] (Step S03: Firing) In step S03, the ceramic green body 111 obtained in step S02 is fired to produce the ceramic green body 11 of the multilayer ceramic capacitor 10 shown in FIGS. 14 and 1-3. The firing temperature in step S04 can be determined based on the sintering temperature of the ceramic green body 111. Further, the firing can be performed, for example, in a reducing atmosphere or in a low oxygen partial pressure atmosphere.

[0061] By firing, each of the side margin portions 119a, 119b, and 119c shrinks at different rates. Specifically, the second side margin portion 119b shrinks with a larger shrinkage amount than the first side margin portion 119a. The third side margin portion 119c shrinks with a larger shrinkage amount than the second side margin portion 119b.

[0062] As a result, as shown in FIG. 14, a gentle step or slope is formed on the ridge portion 11e of the ceramic green body 11. The outer edges of the respective side margin portions 119a, 119b, 119c contract inward in the Z-axis direction in this order to form the recess 23. The outer edge of the side surface Cb of the stacked chip C forms the edge portion 24 on the main surface 11c side. The outer edge of the third side margin portion 119c forms the edge portion 24 on the side surface 11b side.

[0063] In FIG. 14, the regions corresponding to the respective side margin portions 119a, 119b, 119c in the side margin portion 19 are indicated by a dashed-dotted line, but after firing, the boundary becomes almost invisible.

[0064] (Step S04: Formation of the base film) In step S04, a conductive base film 21 is formed, which includes an end surface coating portion 26a formed on the end surface 11a, a side surface coating portion 26b formed on the side surface 11b, a main surface coating portion 26c formed on the main surface 11c, and a recess coating portion 27 formed on the recess 23 and spaced apart from the side surface coating portion 26b and the main surface coating portion 26c, respectively.

[0065] Specifically, first, an unfired electrode material is applied to the end surface 11a, and an unfired electrode material is also applied to a part of the side surface 11b, the main surface 11c, and the ridge portion 11e connected to the end surface 11a. The application method is, for example, the dip method. In the dip method, the end surface 11a side of the ceramic green body 11 is immersed in a dip tank containing an electrode material such as a conductive paste. Thereby, an unfired electrode material can be applied to the side surface 11b, the main surface 11c, and the recess 23 almost simultaneously with the end surface 11a.

[0066] The unfired electrode material is thinly applied so that the recess coating portion 27 after baking, the side surface coating portion 26b, and the main surface coating portion 26c are spaced apart from each other. However, they do not have to be spaced apart at the time of application. The application thickness of the electrode material can be adjusted by the immersion time, the pulling-up speed, the viscosity of the electrode material, etc.

[0067] Note that the method for forming the base film is not limited to the dip method, and for example, a printing method, a sputtering method, or a combination of these methods may be used.

[0068] Subsequently, the unfired electrode material is baked. The baking can be performed, for example, in a reducing atmosphere or in an atmosphere of low oxygen partial pressure. During baking, the electrode material formed on each surface shrinks due to heat. The shrinkage rate of the electrode material is larger than the shrinkage rate of the ceramic body 11. For this reason, the electrode material applied to each surface generates a tensile stress in the direction away from the ridge portion 11e. As a result, the recess covering portion 27, the side surface covering portion 26b, and the main surface covering portion 26c are formed so as to be separated from each other.

[0069] (Step S05: Plating film formation) In step S05, a plating film 22 is formed to continuously cover the end surface covering portion 26a, the side surface covering portion 26b, the main surface covering portion 26c, and the recess covering portion 27. Specifically, the multilayer ceramic capacitor 10 on which the base film 21 is formed is immersed in a plating solution corresponding to each of the intermediate film 28 and the surface layer film 29 to perform electrolytic plating. Thereby, a plating film 22 having a plurality of layers of the intermediate film 28 and the surface layer film 29 is formed.

[0070] As described above, the multilayer ceramic capacitor 10 shown in FIGS. 1 to 3 is manufactured. In the present embodiment, by attaching the side margin portion 119 to the multilayer chip C, the positions of the ends of the internal electrodes 112 and 113 are aligned with each other within a range of 0.5 μm in the Y-axis direction. Thereby, the ratio of the volume occupied by the capacitance forming portion 16 in the ceramic body 11 can be increased, and the capacitance can be increased without increasing the size of the multilayer ceramic capacitor 10.

[0071] [Other embodiments] Although each embodiment of the present invention has been described above, the present invention is not limited only to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0072] The number of ceramic sheets forming each side margin portion 19 is not limited to three. For example, by setting the number of ceramic sheets forming the side margin portion 19 to be two or more and four or less, a concave portion 23 with a desired shape can be formed, and problems such as peeling of the side margin portion 19 after pasting can be prevented.

[0073] For example, in the above embodiment, it was described that the unfired side margin portion 119 is formed by pasting a laminated sheet S in which different ceramic sheets are laminated, but a plurality of ceramic sheets may be pasted one by one.

[0074] Also, the method of pasting the ceramic sheet is not limited to sheet punching, and a ceramic sheet previously cut to a predetermined size may be pasted on the side surface Cb.

[0075] Alternatively, the side margin portion 19 may be formed by applying ceramic materials having different thermal shrinkage rates in layers on the side surface Cb of the laminated chip C. Also by this, a laminated structure of a plurality of side margin portions having different thermal shrinkage rates can be formed.

[0076] Further, by forming the cover portion 18 with a plurality of ceramic sheets having different thermal shrinkage rates, a concave portion can also be formed. In this case, a plurality of ceramic sheets in which side margin portions are formed around the internal electrodes are laminated, and a plurality of ceramic sheets are laminated such that the thermal shrinkage rate gradually increases in the up and down directions of the Z axis. Thereby, a ridge portion including a concave portion is formed at the outer edge portion of the ceramic sheet for forming the cover portion.

[0077] Furthermore, it is not limited to the method of forming the concave portion by thermal shrinkage of the ceramic material, and the concave portion may be formed by grinding the ridge portion of the ceramic green body formed in a rectangular parallelepiped shape.

[0078] In the above embodiment, the multilayer ceramic capacitor 10 has been described as an example of the multilayer ceramic electronic component. However, the present invention is applicable to all multilayer ceramic electronic components in which a ceramic layer and internal electrodes are laminated. Examples of such multilayer ceramic electronic components include chip varistors, chip thermistors, multilayer inductors, and the like.

Explanation of Reference Numerals

[0079] 10... Multilayer ceramic capacitor 11... Ceramic body 11a... End face 11b... Side face 11c... Main face 11e... Ridge portion 12, 13... Internal electrodes 14... External electrodes 21... Underlayer film 22... Plating film 23... Concave portion 24... Edge portion 25... First covering portion (end face covering portion) 26b, 26c... Second covering portions (side face covering portion, main face covering portion) 27... Third covering portion (concave portion covering portion)

Claims

1. A ceramic element having a protective part including an end face facing in a first direction, a plurality of peripheral faces connected to the end face and extending in the first direction, and a ridge part having a recess extending along the first direction and connecting between the plurality of peripheral faces; and a functional part disposed inside the protective part. An external electrode having an underlayer film formed on the end face and a plating film formed on the underlayer film. Comprising: The functional part has a plurality of internal electrodes laminated in a second direction orthogonal to the first direction. The ridge part is located outside the ends of the plurality of internal electrodes in a third direction orthogonal to the first direction and the second direction when viewed from the second direction. The recess is recessed such that, in a cross section including the second direction and the third direction, it slopes outward in the second direction from the peripheral face along the second direction more than the third direction, and slopes outward in the third direction from the peripheral face along the third direction more than the second direction. The underlayer film includes a plurality of second covering parts respectively formed on the plurality of peripheral faces, and a third covering part formed on the recess and spaced apart from at least one of the plurality of second covering parts. The plating film continuously covers the plurality of second covering parts and the third covering part, a multilayer ceramic electronic component.

2. A ceramic element having a protective part including an end face facing in a first direction, a plurality of peripheral faces connected to the end face and extending in the first direction, and a ridge part having a recess extending along the first direction and connecting between the plurality of peripheral faces; and a functional part disposed inside the protective part is produced. An underlayer film is formed on the end face. A plating film is formed on the underlayer film. The functional part has a plurality of internal electrodes laminated in a second direction orthogonal to the first direction. The ridge part is located outside the ends of the plurality of internal electrodes in a third direction orthogonal to the first direction and the second direction when viewed from the second direction. The recess is recessed such that, in a cross section including the second direction and the third direction, it slopes outward in the second direction from the peripheral face along the second direction more than the third direction, and slopes outward in the third direction from the peripheral face along the third direction more than the second direction. The underlayer film includes a plurality of second covering parts respectively formed on the plurality of peripheral faces, and a third covering part formed on the recess and spaced apart from at least one of the plurality of second covering parts. The plating film continuously covers the plurality of second covering portions and the third covering portion, and is a method for manufacturing a multilayer ceramic electronic component.

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