Multilayer ceramic electronic components and their manufacturing methods

Abstract

To improve reliability at high voltages while simultaneously achieving higher capacity and miniaturization. [Solution] The multilayer ceramic electronic component has a laminate comprising a capacitance portion and a cover portion, and a base body comprising a side margin portion. The laminate comprises a plurality of ridge portions extending along a third direction perpendicular to the first and second directions, and the base body comprises a protrusion in at least one of the plurality of ridge portions. The protrusion is continuous with the side margin portion and, in a cross-section including the first and second directions, protrudes outward in the first direction from the center point in the second direction of the main surface, and extends toward the center point of the cover portion beyond the boundary line between the laminate and the side margin portion.

Description

[Technical Field]

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

[0002] Conventionally, multilayer ceramic electronic components such as multilayer ceramic capacitors having a capacitance portion in which internal electrodes and dielectric layers are alternately stacked are known. In recent years, with the progress of development of electronic devices such as smartphones, there are demands for higher capacitance and smaller size of multilayer ceramic capacitors. In response to these demands, proposals have been made to retro-fit side margin portions (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2012-209539 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] By the way, with the expansion of application uses of multilayer ceramic capacitors, an increasing number of usage scenarios involve application of high voltage. For this reason, multilayer ceramic capacitors are also required to have reliability against high voltage. Here, a multilayer ceramic capacitor is a piezoelectric body, and when the operating voltage increases, cracks may occur due to expansion and distortion of the stacked portion caused by the piezoelectric phenomenon. Therefore, in order to improve reliability against high voltage, it is conceivable to increase the thickness of the side margin portions to achieve a structure that avoids the occurrence of cracks. However, when the thickness of the side margin portions is increased, the volume of the capacitance portion becomes relatively small, which hinders the increase in capacitance and size reduction of the multilayer ceramic capacitor. That is, in conventional proposals, it has been difficult to achieve both improved reliability against high voltage, increased capacitance, and size reduction.

[0005] Therefore, the objective of the present invention is to achieve both improved reliability at high voltages and increased capacity and miniaturization. [Means for solving the problem]

[0006] As one embodiment for achieving the above objective, the multilayer ceramic electronic component comprises a laminate having a capacitance portion formed by alternately stacking a first internal electrode layer and a second internal electrode layer along a first direction with a dielectric layer in between, and a pair of cover portions covering the capacitance portion from both sides in the first direction, a base body having a side margin portion covering the laminate from a second direction perpendicular to the first direction, and a pair of main surfaces facing each other along the first direction, a first external electrode formed on the surface of the base body from which the first internal electrode layer is drawn out, and a second internal electrode formed on the surface of the base body so as to be spaced apart from the first external electrode. The laminate comprises a second external electrode from which an electrode layer has been drawn out, and the laminate has a plurality of ridges extending along a third direction perpendicular to the first and second directions, and the base body may be configured such that at least one of the plurality of ridges has a projection that is continuous with the side margin portion, extends along the third direction, and in a cross section including the first and second directions, protrudes outward in the first direction from the center point of the main surface in the second direction, and extends toward the center point side of the main surface beyond the boundary line between the laminate and the side margin portion.

[0007] In the multilayer ceramic electronic component according to the above embodiment, the protruding portion includes, in a plan view from which the main surface is observed, a central region in which at least a part overlaps with the capacitance portion, and end regions that extend to both sides of the central region along the third direction, and the dimension D1 along the second direction of the crossover portion that exceeds the boundary line in the end region can be smaller than the dimension D2 along the second direction of the crossover portion that exceeds the boundary line in the central region.

[0008] Further, in the multilayer ceramic electronic component according to the above aspect, the protrusion includes, in a plan view where the main surface is observed, a central region at least partially overlapping with the capacitance portion, and end regions respectively extending to both sides of the central region along the third direction, and a dimension M1 of the protrusion along the first direction in the end region can be smaller than a dimension M2 of the protrusion along the first direction in the central region.

[0009] Further, in the multilayer ceramic electronic component according to the above aspect, when a dimension of the multilayer ceramic electronic component along the second direction is defined as W, a dimension D1 along the second direction of a cross-border portion crossing the boundary line in the end region and a dimension D2 along the second direction of a cross-border portion crossing the boundary line in the central region can satisfy a relationship of 0 μm ≦ D1 and 0 μm < D2 ≦ W × 1 / 10.

[0010] Further, in the multilayer ceramic electronic component according to the above aspect, when a dimension of the multilayer ceramic electronic component along the first direction is defined as T, a dimension M1 of the protrusion along the first direction in the end region can satisfy a relationship of 0 μm ≦ M1 < T × 1 / 20, and a dimension M2 of the protrusion along the first direction in the central region can satisfy a relationship of 0 μm < M2 ≦ T × 1 / 10.

[0011] Further, in the multilayer ceramic electronic component according to the above aspect, the protrusion can be formed on one of the ridge portions opposing each other in the first direction in a cross-section including the first direction and the second direction.

[0012] Further, in the multilayer ceramic electronic component according to the above aspect, the protrusion can be formed on one of the ridge portions opposing each other in the second direction in a cross-section including the first direction and the second direction.

[0013] Furthermore, in the multilayer ceramic electronic component according to the above embodiment, the first external electrode and the second external electrode each cover a pair of opposing end faces in the base body along the third direction and extend at least to the main surface, the outermost positions of the first external electrode and the second external electrode in the first direction are located in the central portion of the base body in the second direction, and the dimension of the multilayer ceramic electronic component along the first direction is defined as the distance between the outermost positions of the first external electrode or the second external electrode in the first direction.

[0014] In the multilayer ceramic electronic component according to the above embodiment, the first internal electrode layer and the second internal electrode layer may be configured such that the positions of their ends in the second direction are aligned with each other within a range of 0.5 μm in the second direction.

[0015] As another embodiment for achieving the above objective, a method for manufacturing a multilayer ceramic electronic component includes the steps of: producing an unfired laminate having dielectric layers and internal electrodes alternately stacked along a first direction, a capacitance portion in which the internal electrodes are exposed from a side facing a second direction perpendicular to the first direction, and a pair of cover portions covering the capacitance portion from both sides in the first direction; pressing the side of the unfired laminate against a sheet member placed on a first elastic member to punch out the sheet member, thereby forming a side margin portion on the side; and the side margin The method may include the steps of: pressing the din portion against a rigid plate to form an extended portion in which the sheet member forming the side margin portion is spread to an area wider than the side surface region; pressing the side margin portion with the extended portion formed thereon against a second elastic member to cause the extended portion to wrap around each of a pair of opposing main surfaces in the laminate along the first direction, forming a protruding portion that protrudes outward in the first direction, and forming an unfired body; firing the body; and forming an external electrode on the fired body.

[0016] In the method for manufacturing a multilayer ceramic electronic component according to the above embodiment, the hardness of the second elastic member can be lower than that of the first elastic member.

[0017] Furthermore, in the method for manufacturing a multilayer ceramic electronic component according to the above embodiment, the rigid plate may be provided with an extension suppression portion that suppresses the extension of the sheet member forming the side margin portion toward a pair of opposing end faces in the laminate along a third direction perpendicular to the first and second directions. [Effects of the Invention]

[0018] According to the present invention, it is possible to achieve both improved reliability at high voltages and increased capacity and miniaturization. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1(A) is a perspective view of a multilayer ceramic capacitor according to one embodiment of the present invention, and Figure 1(B) is a plan view showing the main surface of the ceramic element of the multilayer ceramic capacitor. [Figure 2] Figure 2 is a plan view showing an enlarged view of the multilayer ceramic capacitor shown in Figure 1(B). [Figure 3] Figure 3(A) is a cross-sectional view of the multilayer ceramic capacitor in Figure 1(B) along the AA-AA line. Figure 3(B) is a cross-sectional view of the multilayer ceramic capacitor in Figure 1(B) along the BB line. [Figure 4] Figure 4(A) is a cross-sectional view of the ceramic element of the multilayer ceramic capacitor in Figure 1(B) along line AA. Figure 4(B) is a cross-sectional view of the multilayer ceramic capacitor in Figure 1(B) along line BB. [Figure 5] Figure 5(A) is an enlarged view of the X1 portion in Figure 4(A). Figure 5(B) is an enlarged view of the X2 portion in Figure 4(B). [Figure 6] Figure 6(A) is a cross-sectional view of the multilayer ceramic capacitor in Figure 1(B) along line AA. Figure 6(B) is a cross-sectional view of the multilayer ceramic capacitor in Figure 1(B) along line BB. Figure 6(C) is a cross-sectional view of a comparative example multilayer ceramic capacitor corresponding to Figure 6(A). [Figure 7]FIG. 7 is a flowchart showing an example of a method for manufacturing a multilayer ceramic capacitor according to an embodiment. [Figure 8] FIG. 8 is a perspective view showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 9] FIG. 9 is a perspective view showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 10] FIGS. 10(A) and 10(B) are schematic cross-sectional views showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 11] FIGS. 11(A) and 11(B) are schematic cross-sectional views showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 12] FIGS. 12(A) and 12(B) are schematic cross-sectional views showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 13] FIG. 13 is a perspective view showing a manufacturing process of the multilayer ceramic capacitor according to the embodiment. [Figure 14] FIGS. 14(A) and 14(B) are cross-sectional views each showing a multilayer ceramic capacitor according to a modified example. DESCRIPTION OF EMBODIMENTS

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, mutually orthogonal T direction, W direction, and L direction axes are shown as appropriate. The T direction, W direction, and L direction are common in all drawings. The T direction corresponds to a first direction, the W direction corresponds to a second direction, and the L direction corresponds to a third direction.

[0021] [Overall Configuration of Multilayer Ceramic Capacitor 10] Figures 1(A) to 6(B) show an example of a multilayer ceramic capacitor 10 according to an embodiment of the present invention. Figure 1(A) is a perspective view of the multilayer ceramic capacitor 10, and Figure 1(B) is a plan view observing the main surface 11c of the ceramic element 11 of the multilayer ceramic capacitor 10. Figure 2 is a plan view showing an enlarged view of the multilayer ceramic capacitor 10 shown in Figure 1(B). Figure 3(A) is a cross-sectional view of the multilayer ceramic capacitor 10 in Figure 1(B) along the line AA-AA. Figure 3(B) is a cross-sectional view of the multilayer ceramic capacitor 10 in Figure 1(B) along the line BB. Figure 4(A) is a cross-sectional view of the ceramic element 11 of the multilayer ceramic capacitor 10 in Figure 1(B) along the line AA. Figure 4(B) is a cross-sectional view of the multilayer ceramic capacitor 10 in Figure 1(B) along the line BB. Figure 5(A) is an enlarged view of portion X1 in Figure 4(A). Figure 5(B) is an enlarged view of portion X2 in Figure 4(B). Figure 6(A) is a cross-sectional view of the multilayer ceramic capacitor 10 in Figure 1(B) along line AA. Figure 6(B) is a cross-sectional view of the multilayer ceramic capacitor 10 in Figure 1(B) along line BB. Figure 6(C) is a cross-sectional view of a comparative example multilayer ceramic capacitor corresponding to Figure 6(A).

[0022] The multilayer ceramic capacitor 10 comprises a ceramic body 11 having a substantially rectangular parallelepiped shape. The ceramic body 11 comprises a pair of opposing end faces 11a along the L direction, a pair of opposing main faces 11c along the T direction, and a pair of opposing side faces 11b along the W direction. The end faces 11a, side faces 11b, and main faces 11c are, for example, substantially flat surfaces, but may also be rounded.

[0023] In the ceramic body 11, a first external electrode 14a and a second external electrode 14b are provided on its surface, spaced apart from each other. In the examples shown in Figures 1(A) to 3(A), the first external electrode 14a is provided on one of the opposing end faces 11a, and the second external electrode 14b is provided on the other. The first external electrode 14a and the second external electrode 14b extend to the side surface 11b and the main surface 11c adjacent to the end face 11a, respectively. However, the first external electrode 14a and the second external electrode 14b are spaced apart from each other.

[0024] The first external electrode 14a and the second external electrode 14b can be provided at any position on the surface of the ceramic body 11, as long as they are spaced apart from each other. For example, the first external electrode 14a and the second external electrode 14b may be provided spaced apart from each other on the same surface of the ceramic body 11, or they may be provided spaced apart from each other on two adjacent or opposing surfaces of the ceramic body 11.

[0025] The first external electrode 14a and the second external electrode 14b may extend from the surface on which they are provided to any surface, as long as they are spaced apart from each other. For example, they may extend to adjacent surfaces, and may extend further from those surfaces.

[0026] The multilayer ceramic component has a first direction, which is the lamination direction; a second direction perpendicular to the lamination direction where two opposing faces intersect; and a third direction perpendicular to both the first and second directions where two opposing faces intersect. The first, second, and third directions are mutually orthogonal. The lamination direction can be set in any of the length, width, or height directions of the ceramic body 11.

[0027] The ceramic body 11 has a structure in which dielectric layers 15 containing a ceramic material that functions as a dielectric and internal electrode layers are alternately stacked. The internal electrode layers comprise a plurality of first internal electrode layers 12 and a plurality of second internal electrode layers 13. The first internal electrode layers 12 and the second internal electrode layers 13 are alternately stacked. In the illustrated example, the edge of the first internal electrode layer 12 is drawn out to the end face 11a on which the first external electrode 14a of the ceramic body 11 is provided. The edge of the second internal electrode layer 13 is drawn out to the end face 11a on which the second external electrode 14b of the ceramic body 11 is provided.

[0028] As a result, the first internal electrode layer 12 is conductive to the first external electrode 14a, and the second internal electrode layer 13 is conductive to the second external electrode 14b. Consequently, the ceramic body 11 has a structure in which capacitor units are stacked, that is, it has a capacitance section 16.

[0029] The ceramic body 11 includes a protective portion 17 that forms the peripheral edge of the volume portion 16. The surface of the protective portion 17 constitutes the end face 11a, the side surface 11b, and the main surface 11c.

[0030] The protective section 17 includes a pair of cover sections 18 that cover the capacity section 16 from both sides in the T direction, side margin sections 19 that cover the capacity section 16 from both sides in the W direction, and an end margin section 20 located on the outside of the capacity section 16 in the L direction.

[0031] The cover portion 18 is located outside the capacitance portion 16 in the stacking direction, that is, outside the capacitance portion 16 in the T direction in the illustrated example. The side margin portion 19 is provided outside the capacitance portion 16 in a direction perpendicular to the stacking direction. The side margin portion 19 is provided as a region that does not include the respective edges of the first internal electrode layer 12 and the second internal electrode layer 13 that are drawn out onto the surface of the ceramic body 11 in a direction perpendicular to the stacking direction. That is, the side margin portion 19 is located outside the capacitance portion 16 in the W direction in the illustrated example. The end margin portion 20 is provided outside the capacitance portion 16 in a direction perpendicular to the stacking direction. The end margin portion 20 is provided as a region that includes the respective edges of the first internal electrode layer 12 and the second internal electrode layer 13 that are drawn out onto the surface of the ceramic body 11 in a direction perpendicular to the stacking direction. That is, the end margin portion 20 is located outside the capacitance portion 16 in the L direction in the illustrated example.

[0032] Here, the capacitance portion 16 and the pair of cover portions 18 covering the capacitance portion 16 constitute a laminate 30. Referring to Figure 3(B), the laminate 30 has four ridge portions 31a, 31b, 31c, and 31d. The four ridge portions 31a, 31b, 31c, and 31d are formed by the continuous arrangement of the corner portions 30a, 30b, 30c, and 30d observed in the cross-section shown in Figure 3(B) along the L direction. In the laminate 30, the positions of the ends of the first internal electrode 112 and the second internal electrode 113 are aligned with each other within a range of 0.5 μm in the W direction.

[0033] The ceramic body 11 is a ridge portion connecting each face of the laminate 30, and has four ridge portions 31a, 31b, 31c, and 31d extending in a third direction, and each of these ridge portions 31a, 31b, 31c, and 31d is covered by a protruding portion 40 of the side margin portion 19. Here, of the four ridge portions, ridge portion 31a will be described as representative. The ridge portion 31a is formed by the continuous corner portion 30a along the L direction. In the cross section shown in an enlarged view in Figure 5(A), that is, the cross section at a position that is 1 / 20th of the length L of the multilayer ceramic capacitor 10 in the direction indicated by arrow 1a from one end of the multilayer ceramic capacitor 10 in the L direction in Figure 1(B) (hereinafter referred to as the end-side WT cross section), the corner portion 30a is the intersection of the first virtual line Lt1 in the first direction and the first virtual line Lw1 in the second direction. Furthermore, the corner 30a of the cross section shown in an enlarged view in Figure 5(B), that is, the cross section at a position that is half the length L

[10] of the multilayer ceramic capacitor 10 in the L direction, in the direction indicated by arrow 1a from one end of the multilayer ceramic capacitor 10 in the L direction in Figure 1(B) (hereinafter referred to as the central WT cross section), is the intersection of the second virtual line Lt2 in the first direction and the second virtual line Lw2 in the second direction. Depending on how the coordinate axes are oriented, the two cross sections of the multilayer ceramic capacitor 10 can be defined as end WT cross sections, but either one of the cross sections may be used to represent the end WT cross section.

[0034] The first virtual line Lt1 in the first direction is an extension of the boundary line where the laminate 30 and the side margin portion 19 are joined in the cross-section shown in Figure 5(A), i.e., the end WT cross-section. The first virtual line Lt1 in the first direction can be defined by observing the boundary line where the laminate 30 and the side margin portion 19 are joined due to differences in material, sintering state, etc. If this joined boundary line is unclear or cannot be observed, the boundary line can be determined by a straight line connecting the ends of the first internal electrode 12 and the second internal electrode 13 along the T direction. However, the positions of the ends of the first internal electrode 12 and the second internal electrode 13 may be slightly offset in the W direction. In this case, for convenience, when a straight line extending in the T direction is moved from the outside in the W direction towards the inside of the ceramic body 11, the position where it first contacts either the first internal electrode 12 or the second internal electrode 13 is defined as the first virtual line Lt1 in the first direction.

[0035] On the other hand, the second direction first virtual line Lw1 is a straight line extending along the W direction from the main surface 11c of the ceramic body 11 in the cross-section shown in Figure 5(A), i.e., the end WT cross-section. However, the main surface 11c may have a shape in which the central part in the W direction protrudes in the T direction. In such cases, for convenience, the position where the straight line extending in the W direction first contacts the main surface 11c when it is moved from the outside in the T direction toward the inside of the ceramic body 11 is defined as the second direction first virtual line Lw1.

[0036] The second virtual line Lt2 in the first direction is an extension of the boundary line where the laminate 30 and the side margin portion 19 are joined in the cross-section shown in Figure 5(B), i.e., the central WT cross-section. The second virtual line Lt2 in the first direction can be defined by observing the boundary line where the laminate 30 and the side margin portion 19 are joined due to differences in material, sintering state, etc. If this joined boundary line is unclear or cannot be observed, a straight line connecting the ends of the first internal electrode 12 and the second internal electrode 13 along the T direction can be determined as the boundary line. However, the positions of the ends of the first internal electrode 12 and the second internal electrode 13 may be slightly offset in the W direction. In this case, for convenience, when a straight line extending in the T direction is moved from the outside in the W direction towards the inside of the ceramic body 11, the position where it first contacts either the first internal electrode 12 or the second internal electrode 13 is defined as the second virtual line Lt2 in the first direction.

[0037] On the other hand, the second virtual line Lw2 in the second direction is a straight line extending along the W direction from the main surface 11c of the ceramic body 11 in the cross-section shown in Figure 5(B), i.e., the central WT cross-section. However, the main surface 11c may be rounded and have a shape in which the central part in the W direction protrudes in the T direction. In such cases, for convenience, when a straight line extending in the W direction is moved from the outside in the T direction toward the inside of the ceramic body 11, the position where it first contacts the main surface 11c is defined as the second virtual line Lw2 in the second direction.

[0038] The other corners 30b to 30d can be defined similarly. The corners 30b to 30d are then continuous along the L direction to form the ridges 31b to 31d.

[0039] The protruding portion 40 is continuous with the side margin portion 19 and extends in a band shape along the L direction (see Figure 2). As shown in Figures 4(A) to 5(B), the protruding portion 40 protrudes outward in the T direction from the center points Wcp1 and Wcp2 in the W direction of the main surface 11c in a cross section that includes the T direction and the W direction, i.e., the end WT cross section or the central WT cross section. Furthermore, as shown in Figures 5(A) and 5(B), the protruding portion 40 extends toward the center points Wcp1 and Wcp2 of the main surface 11c beyond the first virtual line Lt1 and the second virtual line Lt2 in the first direction in a cross section that includes the T direction and the W direction, i.e., the end WT cross section or the central WT cross section. The center point Wcp1 is the point located at the center in the W direction in a cross section along the AA line, which is the cutting line on the end side in Figure 1(A). The center point Wcp2 is the point located at the center in the W direction in a cross section along the BB line, which is the cutting line on the central part in Figure 1(A). The protrusion 40 only needs to be formed on at least one of the four ridge sections 31a, 31b, 31c, and 31d. The protrusion 40 will be described in detail later.

[0040] The capacitance section 16 is located inside the protective section 17 and constitutes the functional section. The capacitance section 16 consists of a plurality of first internal electrodes 12 and a plurality of second internal electrodes 13, which are stacked in the T-axis direction via a dielectric layer 15 (see Figure 2). Both the internal electrodes 12 and 13 are sheet-like structures extending along the LW plane and are arranged alternately along the T-axis direction.

[0041] The first internal electrode layer 12 and the second internal electrode layer 13 are formed from a good electrical conductor and function as internal electrodes of the multilayer ceramic capacitor 10. The good electrical conductors forming the first internal electrode layer 12 and the second internal electrode layer 13 are mainly composed of base metals such as nickel (Ni), copper (Cu), and tin (Sn), or alloys containing these metals. Precious metals such as platinum (Pt), palladium (Pd), silver (Ag), and gold (Au), or alloys containing these metals, may also be used as the main components of the first internal electrode layer 12 and the second internal electrode layer 13. The main components of the first internal electrode layer 12 and the second internal electrode layer 13 may be the same or different.

[0042] The dielectric layer 15 is formed of dielectric ceramics. In the multilayer ceramic capacitor 10, high dielectric constant dielectric ceramics are used to increase the capacitance of each dielectric layer 15 between the first internal electrode 12 and the second internal electrode 13. Examples of high dielectric constant dielectric ceramics include perovskite materials containing barium (Ba) and titanium (Ti), such as barium titanate (BaTiO3).

[0043] Furthermore, the dielectric ceramics may also be of other types besides barium titanate, such as strontium titanate (SrTiO3), calcium titanate (CaTiO3), magnesium titanate (MgTiO3), calcium zirconate (CaZrO3), calcium zirconate titanate (Ca(Zr,Ti)O3), barium zirconate (BaZrO3), or titanium oxide (TiO2). The dielectric ceramics listed here will be the main components of the dielectric layer 15.

[0044] In addition to the main components mentioned above, the dielectric layer 15 may also contain the element Si (silicon).

[0045] The protective portion 17 is also formed from dielectric ceramics. Of the protective portion 17, the cover portion 18 and the end margin portion 20 preferably have the same main component composition as the dielectric layer 15, from the viewpoint of suppressing internal stress. Furthermore, using the same composition improves manufacturing efficiency.

[0046] Of the protective portion 17, the side margin portion 19 has the same main component as the dielectric layer 15. However, during the manufacturing of the multilayer ceramic capacitor 10, the material forming the side margin portion 19 is adjusted in composition compared to the material constituting the dielectric layer 15 and the cover portion 18, i.e., the material constituting the laminate 30, by increasing the plasticizer content or the amount of resin such as binder. This is to allow the side margin portion to be deformed at a lower temperature and pressure compared to the dielectric layer 15 and the cover portion 18 when forming it.

[0047] The side margin portion 19 created in this way may have inferior sinterability compared to the dielectric layer 15 and the cover portion 18, i.e., the laminate 30. To compensate for this, the amount of Si or other additives may be increased. The difference in sinterability between the laminate 30 and the side margin portion 19 is undesirable because it reduces the adhesion strength of the side margin portion 19, but on the other hand, it has the advantage of making it easier to distinguish the boundary between the laminate 30 and the side margin 19 for virtual lines such as Lt1 and Lt2.

[0048] The first external electrode 14a and the second external electrode 14b each have a base film 21 formed to cover the lead-out portion of the first internal electrode layer 12 and the second internal electrode 13 and a part of the surface of the ceramic body 11, 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 firing a conductive paste or a sputtered film. The plating film 22 is a film formed by electroplating. Each film of the external electrodes 14a and 14b is formed of a metal or alloy whose main components are, for example, nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), and Al (aluminum). Alternatively, the external electrodes 14a and 14b can also be formed by printing and drying a conductive paste containing a curable resin, such as resin Ag.

[0049] The dimensions of the multilayer ceramic capacitor 10 in each direction can be expressed as height T

[10] × width W

[10] × length L

[10] , as shown in Figure 1(A). Height T

[10] is the distance between the outermost points along the T direction of the multilayer ceramic capacitor 10. Width W

[10] is the distance between the outermost points along the W direction of the multilayer ceramic capacitor 10. Length L

[10] is the distance between the outermost points along the L direction of the multilayer ceramic capacitor 10.

[0050] The dimensions of the multilayer ceramic capacitor 10 are, for example, length L

[10] =0.25mm, width W

[10] =0.125mm, height T

[10] =0.125mm, or length L

[10] =0.4mm, width W

[10] =0.2mm, height T

[10] =0.2mm, or length L

[10] =0.6mm, width W

[10] =0.3mm, height T

[10] =0.3mm. The dimensions may be, for example, length L

[10] =1.0mm, width W

[10] =0.5mm, height T

[10] =0.5mm, or length L

[10] =3.2mm, width W

[10] =1.6mm, height T

[10] =1.6mm, or length L

[10] =4.5mm, width W

[10] =3.2mm, height T

[10] =2.5mm, but are not limited to these sizes. The dimensions of the multilayer ceramic capacitor 10 may be, for example, length L

[10] >width W

[10] ≧height T

[10] , width W

[10] >length L

[10] ≧height T

[10] , height T

[10] >length L

[10] ≧width W

[10] , or height T

[10] >width W

[10] ≧length L

[10] .

[0051] [Detailed configuration of the protruding portion 40] The protrusion 40 reinforces the capacitance portion 16 and suppresses expansion and distortion that occur in the capacitance portion 16 due to the piezoelectric effect. In other words, the protrusion 40 improves the reliability of the multilayer ceramic capacitor 10 at high voltages. Referring to Figures 4(A) to 5(B), the protrusion 40 is continuous with the side margin portion 19. Referring to Figure 2, the protrusion 40 extends in a band shape along the L direction. The protrusion 40 comprises a central region Arc and end regions Ars located on both sides of the central region Arc along the L direction.

[0052] In Figure 1(B), line AA crosses one end region Ars. In Figure 1(B), line BB crosses the central region Arc. The position where line AA is drawn is at a distance of 1 / 20th of the L-direction dimension L

[10] of the multilayer ceramic capacitor 10, in the direction indicated by arrow 1a, from one end of the multilayer ceramic capacitor 10 in the L-direction. The position where line BB is drawn is at a distance of 1 / 2th of the L-direction dimension L

[10] of the multilayer ceramic capacitor 10, in the direction indicated by arrow 1a, from one end of the multilayer ceramic capacitor 10 in the L-direction.

[0053] The central region Arc is located in the plan view shown in Figures 1(B) and 2, where it overlaps with the capacitance section 16. Each end region Ars is included in the region where the first external electrode 14a or the second external electrode 14b is formed. In this embodiment, the central region Arc overlaps with the entire capacitance section 16 in the L direction, but it is sufficient for it to overlap with at least a part of the capacitance section 16. This is because the capacitance section 16 is reinforced.

[0054] Referring to Figure 5(A), the protrusion 40 extends beyond the first imaginary line Lt1 in the first direction toward the center point Wcp1 of the main surface 11c. Here, the first imaginary line Lt1 in the first direction is an imaginary line segment that extends toward the T direction along the W-oriented surface of the laminate 30, and corresponds to the boundary line between the laminate 30 and the side margin portion 19. The dimension of the cross-boundary portion 40a that extends beyond the first imaginary line Lt1 in the first direction toward the W direction is D1. The dimension of the protrusion 40 toward the T direction is M1. Here, dimension M1 is the dimension of the portion that protrudes outward in the T direction from the center point Wcp1 of the main surface 11c in the cross section shown in Figure 5(A). More specifically, dimension M1 is the distance between the first imaginary line Lw1 in the second direction, drawn along the W direction from the center point Wcp1 of the main surface 11c, and the top of the protrusion 40.

[0055] Referring to Figure 5(B), the protrusion 40 extends beyond the second virtual line Lt2 in the first direction toward the center point Wcp2 of the main surface 11c. Here, the second virtual line Lt2 in the first direction is a virtual line segment that extends toward the T direction along the W-oriented surface of the laminate 30, and corresponds to the boundary line between the laminate 30 and the side margin portion 19. The dimension of the crossover portion 40b that extends beyond the second virtual line Lt2 in the first direction along the W direction is D2. The dimension of the protrusion 40 along the T direction is M2. Here, dimension M2 is the dimension of the portion that protrudes outward in the T direction from the center point Wcp2 of the main surface 11c in the cross section shown in Figure 5(B). More specifically, dimension M2 is the distance between the second virtual line Lw2 in the second direction, drawn along the W direction from the center point Wcp2 of the main surface 11c, and the top of the protrusion 40. Note that in Figure 2, the crossover portion 40b is shown with a mesh. As shown in Figure 2, in a plan view observing the main surface 11c of the multilayer ceramic capacitor 10, the line segment Lb extending along the L direction becomes the boundary line, and the portion beyond this boundary line becomes the cross-boundary portion 40b.

[0056] Dimensions D1, D2, M1, and M2 can be measured by observing their respective cross-sections with a measuring microscope (optical microscope) or scanning electron microscope (SEM) at 500 to 5000x magnification. Specifically, for dimensions D1 and M1, first, the multilayer ceramic capacitor 10 is embedded in resin and polished to a position that is 1 / 20th of L

[10] in the direction indicated by arrow 1a in Figure 1(B). Then, dimensions D1 and M2 are measured in the observation image using an SEM or similar. Measurements can be taken multiple times, for example, 5 times, and the average value can be adopted as each dimension. For dimensions D2 and M2, the multilayer ceramic capacitor 10 is embedded in resin and polished to a position that is 1 / 2th of L

[10] in the direction indicated by arrow 1a in Figure 1(B). Then, dimensions D1 and M2 are measured in the observation image using an SEM or similar. Measurements can be taken multiple times, for example, 5 times, and the average value can be adopted as each dimension.

[0057] In this embodiment, the dimension D1 and the dimension M1 are measured in a cross-section along the line A-A, however, the dimension D1 and the dimension M1 may also be measured in other cross-sections included in the end region Ars. Further, in this embodiment, the dimension D2 and the dimension M2 are measured in a cross-section along the line B-B, however, the dimension D1 and the dimension M1 may also be measured in other cross-sections included in the central region Arc.

[0058] When comparing the dimension D1 of such a cross-border portion 40a and the dimension D2 of the cross-border portion 40b, the relationship D1 < D2 holds. This is because setting a large dimension D2 for the portion overlapping the capacitance portion 16 reinforces the capacitance portion 16, and can suppress expansion and strain generated in the capacitance portion 16 due to the piezoelectric effect. Further, reducing the dimension D1 can minimize the influence on the dimensions of the first external electrode 14a and the second external electrode 14b.

[0059] The dimension D1 can satisfy 0 μm ≦ D1. That is, the dimension D1 has the relationship D1 < D2 with the dimension D2. Therefore, the dimension of the protruding portion 40 in the W direction can be configured to gradually decrease from the central portion in the L direction of the multilayer ceramic capacitor 10 toward both end portions. At this time, the dimension D1 may become 0 μm before reaching the end portion of the ceramic body 11 in the L direction.

[0060] Furthermore, the dimension D2 has the following relationship with the width W

[10] of the multilayer ceramic capacitor 10. That is, the dimension D2 satisfies the relationship 0 μm < D2 ≦ W

[10] × 1 / 10. The relationship 0 μm < D2 means that the dimension D2 is larger than 0 μm, the cross-border portion 40b is necessarily present, and a portion overlapping the capacitance portion 16 is provided. This allows the protruding portion 40 to function as a reinforcement for the capacitance portion 16.

[0061] It should be noted that, as described above, the dimension of the protruding portion 40 in the W direction can be configured to gradually decrease from the central portion in the L direction of the multilayer ceramic capacitor 10 toward both end portions. Therefore, the dimension D2 may become 0 μm before reaching the end region Ars, and the protruding portion 40 may not be observed in cross-sections other than the cross-section along the line B-B. In other words, the condition 0 μm < D2 only needs to be satisfied in a certain cross-section included in the central region Arc, and D2 may be 0 μm in other cross-sections.

[0062] The relationship D2≦W

[10] ×1 / 10, that is, the relationship that the dimension D2 is one tenth of the width W

[10] of the multilayer ceramic capacitor 10, is defined as a condition for ensuring the moisture resistance of the multilayer ceramic capacitor 10. The method for manufacturing the multilayer ceramic capacitor 10 of the present embodiment will be described in detail later. The protruding portion 40 is formed by wrapping around an extended portion obtained by spreading a sheet member that forms the side margin portion 19. Therefore, there is a correlation between the dimension D2 of the protruding portion 40 and particularly the thickness t19c of the side margin portion 19 in the central region Arc (see FIG. 5(B)). That is, as the dimension D2 of the protruding portion 40 increases, the thickness t19c of the side margin portion 19 decreases correspondingly. If the thickness t19c of the side margin portion 19 becomes too thin, the moisture resistance of the multilayer ceramic capacitor 10 may be degraded. Therefore, in the present embodiment, the moisture resistance of the multilayer ceramic capacitor 10 is ensured by maintaining the relationship D2≦W

[10] ×1 / 10. It should be noted that the thickness t19b of the side margin portion 19 in the end region Ars shown in FIG. 5(A) tends to be larger than the thickness t19c of the side margin portion 19 in the central region Arc. For this reason, in the present embodiment, an upper limit is set for the dimension D2, which has a high correlation with the thickness t19c of the side margin portion 19 that is subject to stricter conditions.

[0063] Next, when comparing the dimension M1 of the protruding portion 40 in the end region Ars and the dimension M2 of the protruding portion 40 in the central region Arc, the relationship M1 < M2 holds. This is because setting a large dimension M2 for the portion overlapping the capacitor portion 16 reinforces the capacitor portion 16 and can suppress expansion and strain generated in the capacitor portion 16 due to the piezoelectric phenomenon. Furthermore, reducing the dimension M1 minimizes the influence on the dimensions of the first external electrode 14a and the second external electrode 14b.

[0064] The dimension M1 has the following relationship with the height T

[10] of the multilayer ceramic capacitor 10. That is, the dimension M1 satisfies the relationship 0 μm ≦ M1 < T

[10] × 1 / 20. Satisfying this relationship mitigates the influence of swelling caused by the surface tension of the external electrode material when the first external electrode 14a and the second external electrode 14b are formed.

[0065] Here, the dimension T

[10] of the multilayer ceramic capacitor 10 shown in FIG. 6(A) will be described in comparison with the dimension T

[0100] of the multilayer ceramic capacitor 100 of the comparative example shown in FIG. 6(C). Unlike the multilayer ceramic capacitor 10 of the embodiment, the multilayer ceramic capacitor 100 of the comparative example does not include the protruding portion 40.

[0066] It is known that when an external electrode is formed, the electrode thickness tends to increase at the central portion in the T direction and the central portion in the W direction due to the influence of the surface tension of the material forming the external electrode. For this reason, the dimension T

[0100] of the multilayer ceramic capacitor 100 of the comparative example is the distance between the outermost positions in the T direction of the first external electrode 114a. Note that the dimension T

[0100] of the multilayer ceramic capacitor 100 of the comparative example may also be the distance between the outermost positions in the T direction of the second external electrode (not shown).

[0067] On the other hand, the dimension T

[10] of the multilayer ceramic capacitor 10 according to the embodiment is also the distance between the outermost positions in the T direction of the first external electrode 14a or the second external electrode 14b. Here, the outermost position in the T direction of the first external electrode 14a or the second external electrode 14b is generally located at the central portion in the W direction of the multilayer ceramic capacitor 10.

[0068] However, if the dimension D1 becomes excessively large, it is assumed that the portion covering the protrusion 40 of the external electrode will protrude beyond the outermost position in the T direction of the external electrode at the central portion in the W direction of the multilayer ceramic capacitor 10. In this case, the portion covering the protrusion 40 of the external electrode becomes the outermost position in the T direction of the entire external electrode. This results in an increase in size of the multilayer ceramic capacitor 10.

[0069] By satisfying the relationship of M1<T

[10] ×1 / 20, the height T

[10] of the multilayer ceramic capacitor 10 is not affected. That is, it is possible to prevent the portion covering the protrusion 40 of the external electrode from becoming the outermost position in the T direction in the entire external electrode, and suppress the size increase of the multilayer ceramic capacitor 10.

[0070] Further, since 0 μm≦M1, the dimension in the T direction of the protrusion 40 in the end region Ars may be 0 μm. The dimension M1 has a relationship of M1<M2 with the dimension M2. Therefore, the dimension in the T direction can be configured to gradually decrease from the central portion in the L direction of the multilayer ceramic capacitor 10 toward both end portions. At this time, the dimension M1 may become M1=0 μm before reaching the end portion in the L direction of the ceramic body 11.

[0071] Referring to FIG. 6(A), the multilayer ceramic capacitor 10 according to the embodiment includes the protrusion 40, so that the portion covering the protrusion 40 of the first external electrode 14a is raised, and a stepped portion 14a1 having a height G

[10] is formed between the portion and the central portion in the W direction. Such a stepped portion is similarly formed also on the second external electrode 14b.

[0072] In contrast, in the multilayer ceramic capacitor 100 of the comparative example shown in FIG. 6(C), such a stepped portion is not formed, and the surface shape of the first external electrode 114a has a curved portion that continues from the portion covering the main surface 110c to the portion covering the side surface 110b. Since the comparative example does not include a stepped portion as described above, for convenience, the distance between the main surface 110c and the outermost position in the T direction of the first external electrode 114a is defined as height G

[0100] .

[0073] When comparing the height G

[10] of the stepped portion 14a1 in the embodiment with the height G

[0100] in the comparative example, the relationship G

[10] <G

[0100] holds. Accordingly, the multilayer ceramic capacitor 10 of the embodiment is less likely to roll than the multilayer ceramic capacitor 100 of the comparative example. Further, in contrast to the comparative example having a curved portion continuous from the portion covering the main surface 110c to the portion covering the side surface 110b, each surface shape of the portion continuous via the stepped portion 14a1 is also nearly smooth. It can be said from such a shape that the multilayer ceramic capacitor 10 of the embodiment is less likely to roll. Since the multilayer ceramic capacitor 10 is less likely to roll, it can be mounted in a stable state.

[0074] Next, the dimension M2 will be described. The dimension M2 has the following relationship with the dimension T

[10] . That is, it satisfies the relationship of M2≦T

[10] ×1 / 10. If the dimension M2 also becomes excessively large, it is assumed that the external electrode will protrude beyond the outermost position in the T direction. Therefore, by maintaining the relationship of M2≦T

[10] ×1 / 10, the height T

[10] of the multilayer ceramic capacitor 10 can be defined as the distance between the outermost positions in the T direction of the first external electrode 14a or the second external electrode 14b. Accordingly, an increase in size of the multilayer ceramic capacitor 10 can be suppressed.

[0075] [Method for Manufacturing Multilayer Ceramic Capacitor 10] Next, an example of a manufacturing method for the multilayer ceramic capacitor 10 will be described. Figure 7 is a flowchart showing the manufacturing method for the multilayer ceramic capacitor 10. Figures 8 to 13 are schematic diagrams showing the manufacturing process of the multilayer ceramic capacitor 10. The manufacturing method for the multilayer ceramic capacitor 10 will be described below, following Figure 9 and referring to Figures 8 to 13 as appropriate.

[0076] (Step S01: Fabrication of laminate C) In step S01, an unfired ceramic laminate (laminated body) C is produced by stacking ceramic sheets 101 and 102 for forming the volume section 16 and ceramic sheet 103 for forming the cover section 18, and then cutting the stack.

[0077] The ceramic sheets 101, 102, and 103 shown in Figure 8 are composed of unfired dielectric green sheets containing a ceramic material made of dielectric ceramics, an organic binder, and other additives. An unfired first internal electrode layer 112 corresponding to the first internal electrode layer 12 is formed on ceramic sheet 101. An unfired second internal electrode layer 113 corresponding to the second internal electrode layer 13 is formed on ceramic sheet 102. No internal electrode layer is formed on ceramic sheet 103.

[0078] Each unfired internal electrode layer 112, 113 has multiple strip-shaped electrode patterns that cross a cutting line Lx parallel to the L direction and extend along a cutting line Ly parallel to the W direction. These unfired internal electrode layers 112, 113 are formed by applying a conductive paste to ceramic sheets 101, 102 by printing or the like.

[0079] As shown in Figure 8, ceramic sheets 101 and 102 are stacked alternately in the T direction. The stack of ceramic sheets 101 and 102 corresponds to the volume section 16 and the end margin section 20. Ceramic sheet 103 is stacked on the upper and lower surfaces of the stack of ceramic sheets 101 and 102 in the T direction. The stack of ceramic sheets 103 corresponds to the cover section 18. The number of stacked ceramic sheets 101, 102, and 103 can be adjusted as appropriate.

[0080] Next, the laminate of ceramic sheets 101, 102, and 103 is pressed together from the T direction and cut along the cutting lines Lx and Ly. This produces the laminate C shown in Figure 9.

[0081] The laminate C has an unfired capacitance portion 116 on which unfired internal electrode layers 112 and 113 are formed, an unfired cover portion 118, and an unfired end margin portion 120. The laminate C has a side surface Cb which is a cut surface corresponding to the cutting line Lx, and an end surface Ca which is a cut surface corresponding to the cutting line Ly. The ends of the unfired internal electrode layers 112 and 113 are exposed from the side surface Cb.

[0082] (Step S02: Formation of side margin portion 119 and protrusion portion 140) In step S02, a side margin portion 119 is formed on the side surface Cb of the laminate C, and a protrusion portion 140 is also formed. An example of the formation method is shown below.

[0083] First, a ceramic sheet 104 for the side margin portion 119 is prepared. The ceramic sheet 104 is composed of an unfired dielectric green sheet containing a ceramic material made of dielectric ceramics, an organic binder, and other additives. Compared to ceramic sheets 101 to 103, the ceramic sheet 104 has an increased plasticizer content to make it easier to deform at lower temperatures and pressures. In addition, the composition of the ceramic sheet 104 is adjusted by increasing the amount of resin such as the binder, either by increasing the plasticizer content or by increasing the amount of resin such as the binder.

[0084] The ratio can be set as follows, for example. That is, the amount of plasticizer in the laminate C is 0 wt% to 1 wt% relative to the dielectric material, while the amount of plasticizer in the side margin portion 119 is 2 wt% to 4 wt% relative to the dielectric material. Similarly, the amount of binder in the laminate C is 2 wt% to 11 wt% relative to the dielectric material, while the amount of binder in the side margin portion 119 can be 12 wt% to 20 wt% relative to the dielectric material. This makes the unfired side margin portion 119 easier to deform.

[0085] To form the side margin portion 119 with the ceramic sheet 104, first, as shown in Figure 10(A), the ceramic sheet 104 is placed on the flat first elastic member E1. Then, the other side Cb of the laminate C, which has one side Cb held by the tape TP, is brought to face the ceramic sheet 104. The first elastic member E1 is formed of an elastic material such as rubber.

[0086] Next, as shown in Figure 10(B), the ceramic sheet 104 is attached to the side Cb of the laminate C by punching it out. Specifically, the laminate C is strongly pressed against the ceramic sheet 104 in the W direction. As a result, the laminate C sinks locally and deeply into the first elastic member E1 together with the ceramic sheet 104. At this time, a shear force acts on the ceramic sheet 104 along the outer edge of the side Cb, and when this shear force exceeds the shear strength of the ceramic sheet 104, the ceramic sheet 104 is punched out. Then, a part of the ceramic sheet 104 that sank together with the laminate C is separated. As a result, a side margin portion 119 is formed on the side Cb.

[0087] Next, the process for creating the extended portion 119a will be described with reference to Figures 11(A) and 11(B). The extended portion 119a is the portion that will become the unfired protrusion 140. The extended portion 119a is created by pressing the side margin portion 119, which is formed by the ceramic sheet 104, a sheet member, on the side surface Cb of the laminate C, against the rigid plate RP. As a result, the side margin portion 119 extends in the T direction as indicated by arrow 1b. The portion of the side margin portion 119 that extends to an area wider than the area of ​​the laminate C becomes the extended portion 119a. Here, the rigid plate RP is provided with an extension suppression portion RP1 that suppresses the extension of the ceramic sheet 104 forming the side margin portion 119 toward a pair of opposing end faces Ca in the L direction of the laminate C. The extension suppression portion RP1 is a groove-shaped portion having a width corresponding to the dimension of the laminate C in the L direction. The end face Ca is the area where the first external electrode 14a and the second external electrode 14b will be formed later. Therefore, it is necessary to avoid the ceramic sheet 104 wrapping around the end face Ca. By providing a groove-shaped spreading suppression section RP1, it is possible to suppress the spreading of the ceramic sheet 104 that could potentially wrap around the end face Ca.

[0088] Next, with reference to Figures 12(A) and 12(B), the process of forming an unfired protrusion 40 that protrudes outward in the T direction of the laminate C will be described. Specifically, as shown in Figure 12(A), the side margin portion 119 on which the extended portion 119a is formed is pressed against a flat second elastic member E2. The second elastic member E2 is placed on a high-rigidity support plate SP. Here, the second elastic member E2 is formed of an elastic material such as rubber, but its hardness is lower than that of the first elastic member E1. As a result, as shown in Figure 12(B), the side margin portion 119 can slide inward into the second elastic member E2. As a result, the extended portion 119a wraps around to the main surface Cc side of the laminate C, and the protrusion is formed.

[0089] Similarly, a side margin portion 119 and a protrusion portion 140 are formed on the other side Cb. This results in the production of the unfired ceramic body 111 shown in Figure 13.

[0090] (Step S03: Firing) In step S03, the unfired ceramic body 111 obtained in step S02 is fired to produce the ceramic body 11 of the multilayer ceramic capacitor 10 shown in Figure 1. The firing temperature in step S03 can be determined based on the sintering temperature of the ceramic body 111. Furthermore, firing can be carried out, for example, under a reducing atmosphere or a low oxygen partial pressure atmosphere.

[0091] (Step S04: Formation of the undercoat) In step S04, a conductive undercoat 21 is formed on the end face 11a, side face 11b, and main face 11c as shown in Figures 3(A) and 4(B), etc.

[0092] The base film 21 is prepared by applying unfired electrode material to the end face 11a, side face 11b, and main face 11c. The application method is, for example, the dipping method, but other conventionally known methods such as printing or sputtering, or a combination thereof, may also be used. Subsequently, the unfired electrode material is fired. The firing can be performed, for example, under a reducing atmosphere or under a low oxygen partial pressure atmosphere.

[0093] (Step S05: Plating film formation) In step S05, the multilayer ceramic capacitor 10, on which the base film 21 has been formed, is immersed in a plating solution that forms the plating film 22, and electroplating is performed. This forms the plating film 22.

[0094] Based on the above, the multilayer ceramic capacitor 10 shown in Figures 1-3 is manufactured.

[0095] [Differentiation] Next, modified examples will be described with reference to Figures 14(A) and 14(B). In the multilayer ceramic capacitor 10 of the above-described embodiment, protrusions 40 are provided on four ridges of the ceramic body 11. Therefore, as shown in Figures 4(A) to 4(B), four protrusions 40 appear in a cross-section including the T direction and the W direction. In contrast, in the modified multilayer ceramic capacitor 50, as shown in Figure 14(A), the protrusions are formed on one of the ridges opposite to the T direction in a cross-section including the T direction and the W direction. Furthermore, in another modified multilayer ceramic capacitor 51, as shown in Figure 14(B), the protrusions are formed on one of the ridges opposite to the W direction in a cross-section including the T direction and the W direction. In these modified examples, protrusions are provided on two of the four ridges. The protrusions may be provided on a pair of ridges located diagonally opposite each other in a cross-section including the T direction and the W direction. Furthermore, the protruding portion can also be provided on a single ridge line in a cross-section that includes both the T-direction and the W-direction.

[0096] Although various embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. [Examples]

[0097] [Humidity resistance evaluation and dielectric strength evaluation] First, the results of the humidity resistance evaluation and voltage withstand test for the example will be explained along with the comparative example. The example corresponds to the multilayer ceramic capacitor 10 of the embodiment and has the dimensions shown below. The example and the comparative example differ in dimension D2. Dimension D2 was measured in Figure 1(B) at a position indicated by arrow 1a, from one end of the multilayer ceramic capacitor 10 in the L direction, at a point that is half the length L

[10] of the multilayer ceramic capacitor 10 in the L direction. Dimension D2 was measured in a cross-sectional image taken with an SEM (Scanning Electron Microscope). The width W

[10] of the multilayer ceramic capacitor 10 was measured using a length measuring microscope, at the maximum dimension along the W direction of the multilayer ceramic capacitor 10. The number of measurements n was set to n=20. The average value was then taken as the width W

[10] of the multilayer ceramic capacitor 10 being measured.

[0098] The conditions for the moisture resistance evaluation test are shown below. Test conditions: The ambient temperature is 40°C and the ambient humidity is 95%. Rated voltage: 500 hours. Dimensions of the item under test: 1005 (Length x Width x Height = 1.0mm x 0.5mm x 0.5mm) Number of items tested: Each example and comparative example should consist of 1000 units.

[0099] For the withstand voltage, the voltage applied to the multilayer ceramic capacitor 10 was continuously increased, and the withstand voltage value was defined as the voltage at which the current exceeded 50mA.

[0100] [Table 1]

[0101] (Example 1) In Example 1, dimension D2 is given by dimension D2 = width W

[10] × 1 / 30. In other words, dimension D2 is 1 / 30th of width W

[10] . The moisture resistance failure rate (hereinafter referred to as the moisture resistance NG rate) in Example 1 was 0%. The withstand voltage was 122V. It was determined that the multilayer ceramic capacitor 10 was moisture-resistant if its insulation resistance value, measured at the rated voltage, was less than 1MΩ.

[0102] (Example 2) In Example 2, dimension D2 is given by D2 = width W

[10] × 1 / 20. In other words, dimension D2 is 1 / 20 of width W

[10] . The moisture resistance NG rate for Example 2 was 0%. The withstand voltage was 125V.

[0103] (Example 3) In Example 3, dimension D2 is given by D2 = width W

[10] × 1 / 10. In other words, dimension D2 is one-tenth of the width W

[10] . The humidity resistance NG rate in Example 2 was 0%. The withstand voltage was 135V.

[0104] (Comparative Example 1) In Comparative Example 1, dimension D2 is 0. In other words, Comparative Example 1 does not have a protrusion 40. The moisture resistance NG rate of Comparative Example 1 was 0%. The withstand voltage was 120V.

[0105] (Comparative Example 2) In Comparative Example 2, dimension D2 is given by D2 = width W

[10] × 1 / 9. In other words, dimension D2 is 1 / 9 of width W

[10] . The moisture resistance NG rate of Comparative Example 2 was 0.1%. The withstand voltage was 135V.

[0106] (Comparative Example 3) In Comparative Example 3, dimension D2 is given by dimension D2 = width W

[10] × 1 / 5. In other words, dimension D2 is one-fifth of width W

[10] . The moisture resistance NG rate of Comparative Example 2 was 1%. The withstand voltage was 137V.

[0107] In Table 1, the dimension D2 increases as going toward the right side. Further, the withstand voltage increases as going toward the right side. That is, the withstand voltage increases as the dimension D2 increases. This is considered to be because, as the dimension D2 increases, the area where the protruding portion 40 overlaps the capacitance portion 16 becomes larger.

[0108] However, in Comparative Example 2 and the comparative example, cases may occur where it is determined to be a moisture resistance failure in the moisture resistance evaluation. This is considered to be because, when the dimension D2 increases, the thickness t19c of the side margin portion 19 decreases as a trade-off.

[0109] Considering these factors, it can be said that the appropriate range of the dimension D2 is 0 μm < D2 ≤ W

[10] × 1 / 10. Within this range, the reliability against high voltage is improved, and the increase in capacitance and size reduction of the multilayer ceramic capacitor 10 can be achieved without increasing the thickness of the side margin portion 19.

[0110] [Variation Rate of Height T

[10] ] Next, the variation rate of the height T

[10] will be considered in relation to the dimension M1. The height T

[10] is set in the following procedure. First, it is assumed that the outermost position in the T direction exists at the center portion in the W direction of the first external electrode 14a or the second external electrode 14b, and the height T

[10] is defined as the distance between the outermost positions. That is, the dimension in the T direction at the center portion in the W direction of the first external electrode 14a or the second external electrode 14b is defined as the height T

[10] . For such height T

[10] , a length-measuring microscope was used to measure the maximum dimension along the T direction of the multilayer ceramic capacitor 10. The number of measurements n was set to n=20. The average value thereof was taken as the height T

[10] of the measured multilayer ceramic capacitor 10. However, as a method for setting the height T

[10] , the distance between the outermost positions may be measured for both the first external electrode 14a and the second external electrode 14b, and the longer distance may be adopted. Further, the variation rate of the height T

[10] may be evaluated for each of the first external electrode 14a and the second external electrode 14b.

[0111] The height T

[10] variation rate evaluates the extent to which the measured value exceeds the height T

[10] when the dimension in the T direction is measured at locations other than where the height T

[10] was measured. Therefore, when the dimension in the T direction at locations other than where the height T

[10] was measured is smaller than the height T

[10] , the height T

[10] variation rate is evaluated as 0%.

[0112] The example corresponds to the multilayer ceramic capacitor 10 of the embodiment and has the dimensions shown below. The example and comparative example differ in dimension M1. Dimension M1 was measured in Figure 1(B) at a position indicated by arrow 1a, from one end of the multilayer ceramic capacitor 10 in the L direction, at a point that is 1 / 20th of the length L

[10] of the multilayer ceramic capacitor 10 in the L direction. Dimension M1 was measured in a cross-sectional image taken by SEM.

[0113] Dimensions of the item under test: 1005 (Length x Width x Height = 1.0mm x 0.5mm x 0.5mm)

[0114] [Table 2]

[0115] (Example 4) In Example 4, dimension M1 is given by dimension M1 = height T

[10] × 1 / 30. In other words, dimension M1 is 1 / 30 of height T

[10] . The variation rate of height T in Example 4 (hereinafter referred to as the T dimension variation rate) was 0%.

[0116] (Example 5) In Example 5, dimension M1 is given by dimension M1 = height T

[10] × 1 / 20. In other words, dimension M1 is 1 / 20 of height T

[10] . The T dimension variation rate in Example 5 was 0%.

[0117] (Comparative Example 4) In Comparative Example 4, dimension M1 is equal to 0. In other words, Comparative Example 4 does not have a protrusion 40. The T dimension variation rate of Comparative Example 4 was 0%.

[0118] (Comparative Example 5) The dimension M1 in Comparative Example 5 satisfies the relation: dimension M1 = height T

[10] × 1 / 10. That is, the dimension M1 is one tenth of the height T

[10] . The T-dimension variation rate of Example 5 was 5%.

[0119] (Comparative Example 6) The dimension M1 in Comparative Example 6 satisfies the relation: dimension M1 = height T

[10] × 1 / 9. That is, the dimension M1 is one ninth of the height T

[10] . The T-dimension variation rate of Example 6 was 6%.

[0120] In Table 2, the dimension M1 increases as moving toward the right side of the table. When the dimension M1 increases and satisfies dimension M1 ≧ height T

[10] × 1 / 10, the T-dimension variation rate becomes larger than 0. This is because as the dimension M1 of the protruding portion 40 increases, the outermost position of the multilayer ceramic capacitor 10 in the T-direction shifts outward in the W-direction from the center portion in the W-direction of the first external electrode 14a and the second external electrode 14b. For this reason, in Comparative Example 5 and Comparative Example 6, the multilayer ceramic capacitor 10 is increased in size.

[0121] Considering these circumstances, it can be concluded that the appropriate range for the dimension M1 is 0 μm ≦ M1 < T

[10] / 20. Within this range, reliability against high voltage is improved, and higher capacity and size reduction of the multilayer ceramic capacitor 10 can be achieved without increasing the thickness of the side margin portion 19.

[0122] Next, the variation rate of the height T

[10] is examined in relation to the dimension M2. Since the height T

[10] is set in the same manner as described above, detailed description thereof is omitted herein.

[0123] The example corresponds to the multilayer ceramic capacitor 10 of the embodiment and has the dimensions shown below. The example and comparative example differ in dimension M2. Dimension M2 was measured in Figure 1(B) at a position indicated by arrow 1a, from one end of the multilayer ceramic capacitor 10 in the L direction, at a point that is half the length L

[10] of the multilayer ceramic capacitor 10 in the L direction. Dimension M1 was measured in a cross-sectional image taken by SEM.

[0124] Dimensions of the item under test: 1005 (Length x Width x Height = 1.0mm x 0.5mm x 0.5mm)

[0125] [Table 3]

[0126] (Example 6) In Example 6, dimension M2 is given by dimension M2 = height T

[10] × 1 / 30. In other words, dimension M2 is 1 / 30 of height T

[10] . The T dimension variation rate in Example 6 was 0%.

[0127] (Example 7) In Example 7, dimension M2 is given by dimension M2 = height T

[10] × 1 / 20. In other words, dimension M2 is 1 / 20 of height T

[10] . The variation rate of dimension T in Example 7 was 0%.

[0128] (Example 8) In Example 8, dimension M2 is given by dimension M2 = height T

[10] × 1 / 10. In other words, dimension M2 is one-tenth of height T

[10] . The T dimension variation rate in Example 8 was 0%.

[0129] (Comparative Example 7) In Comparative Example 7, dimension M2 is equal to 0. In other words, Comparative Example 7 does not have a protruding portion 40. The T dimension variation rate of Comparative Example 7 was 0%. (Comparative Example 8) In Comparative Example 8, dimension M2 is given by dimension M2 = height T

[10] × 1 / 9. In other words, dimension M2 is 1 / 9 of height T

[10] . The variation rate of dimension T in Comparative Example 8 was 1%.

[0130] (Comparative Example 9) In Comparative Example 9, dimension M2 is given by M2 = height T

[10] × 1 / 5. In other words, dimension M2 is one-fifth of height T

[10] . The variation rate of dimension T in Comparative Example 9 was 20%.

[0131] Table 2 shows that the dimension M2 increases as you move to the right. Furthermore, as the dimension M2 increases, and the dimension M2 ≥ height T

[10] × 1 / 9, the T dimension variation rate becomes greater than 0. This is because the dimension M2 at the protruding portion 40 increases, and the outermost position of the multilayer ceramic capacitor 10 in the T direction shifts from the center in the W direction of the first external electrode 14a and the second external electrode 14b to the center in the L direction. For this reason, the multilayer ceramic capacitor 10 becomes larger in Comparative Examples 8 and 9.

[0132] Considering these factors, it can be said that the appropriate range for dimension M1 is M2 ≤ T

[10] × 1 / 10. Within this range, reliability against high voltage can be improved, and the capacitance and size of the multilayer ceramic capacitor 10 can be increased without increasing the thickness of the side margin portion 19.

[0133] In the above embodiment, a multilayer ceramic capacitor 10 was described as an example of a multilayer ceramic electronic component, but the present invention is applicable to all multilayer ceramic electronic components in which a dielectric layer and internal electrodes are stacked. Examples of such multilayer ceramic electronic components include chip varistors, chip thermistors, and multilayer inductors. [Explanation of Symbols]

[0134] 10, 50, 51… Multilayer ceramic capacitor, 11… Ceramic base body (base body), 11a… End face, 11b… Side surface, 11c… Main surface, 12… First internal electrode, 13… Second internal electrode, 14a… First external electrode, 14b… Second external electrode, 15… Dielectric layer, 16… Capacitance part, 17… Protection part, 18… Cover part, 19… Side margin part, 20… End margin part, 30… Laminate, 30a~30b… Corner part, 40… Protruding part, 40a, 40 b...Boundary portion, 101, 102, 103, 104...Ceramic sheet, C...Laminate, 119...Unfired side margin portion, 119a...Extended portion, TP...Tape, E1...First elastic member, E2...Second elastic member, RP...Rigid plate, RP1...Groove portion, SP...Support plate, Arc...Center region, Ars...End region, Lt1...First virtual line in the first direction, Lt2...Second virtual line in the first direction, Lw1...First virtual line in the second direction, Lw2...Second virtual line in the second direction

Claims

1. A laminate comprising a capacitance portion formed by alternately stacking a first internal electrode layer and a second internal electrode layer along a first direction with a dielectric layer in between, and a pair of cover portions covering the capacitance portion from both sides in the first direction, and a base body having a side margin portion covering the laminate from a second direction perpendicular to the first direction, and a pair of main surfaces facing each other along the first direction, The body comprises a first external electrode formed on the surface of the body, from which the first internal electrode layer is drawn out, and a second external electrode formed on the surface of the body so as to be spaced apart from the first external electrode, from which the second internal electrode layer is drawn out. The laminate comprises a plurality of ridges extending along a third direction perpendicular to the first and second directions, The base body has, in at least one of the plurality of ridge portions, a projection that is continuous with the side margin portion, extends along the third direction, and in a cross-section including the first direction and the second direction, protrudes outward in the first direction from the center point of the main surface in the second direction, and extends toward the center point side of the main surface beyond the boundary line between the laminate and the side margin portion. Multilayer ceramic electronic components.

2. The protruding portion includes, in a plan view from which the main surface is observed, a central region in which at least a part overlaps with the volume portion, and end regions that extend to both sides of the central region along the third direction. In the end region, the dimension D1 along the second direction of the crossover portion that exceeds the boundary line is smaller than the dimension D2 along the second direction of the crossover portion that exceeds the boundary line in the central region. The multilayer ceramic electronic component according to claim 1.

3. The protruding portion includes, in a plan view from which the main surface is observed, a central region in which at least a part overlaps with the volume portion, and end regions that extend to both sides of the central region along the third direction. The dimension M1 along the first direction in the end region of the protrusion is smaller than the dimension M2 along the first direction in the central region of the protrusion. The multilayer ceramic electronic component according to claim 1.

4. When the dimension of the multilayer ceramic electronic component along the second direction is denoted as W, The dimension D1 along the second direction of the portion that crosses the boundary line in the end region and the dimension D2 along the second direction of the portion that crosses the boundary line in the central region are The relationships 0 μm ≤ D1 and 0 μm < D2 ≤ W × 1 / 10 are satisfied. The multilayer ceramic electronic component according to claim 2.

5. When the dimension of the multilayer ceramic electronic component along the first direction is T, The dimension M1 along the first direction in the end region of the protruding portion satisfies the relationship 0 μm ≤ M1 < T × 1 / 20. The dimension M2 along the first direction in the central region of the protruding portion is The relationship 0 μm < M² ≤ T × 1 / 10 is satisfied. The multilayer ceramic electronic component according to claim 3.

6. The protruding portion is formed on one of the ridge portions that are opposite to the first direction in a cross-section including the first direction and the second direction. The multilayer ceramic electronic component according to claim 1.

7. The aforementioned protrusion is formed on one of the ridges of the ridges that are opposite to the second direction in a cross-section including the first direction and the second direction. The multilayer ceramic electronic component according to claim 1.

8. The first external electrode and the second external electrode each cover a pair of opposing end faces in the substrate along the third direction and extend at least to the main surface. The outermost positions of the first external electrode and the second external electrode in the first direction are located in the central portion of the body in the second direction. The dimension of the multilayer ceramic electronic component along the first direction is defined as the distance between the outermost positions of the first external electrode or the second external electrode in the first direction. The multilayer ceramic electronic component according to claim 1.

9. The first internal electrode layer and the second internal electrode layer are aligned with each other within a range of 0.5 μm in the second direction at the positions of their ends in the second direction. The multilayer ceramic electronic component according to claim 1.

10. A step of manufacturing an unfired laminate comprising a capacitance portion in which dielectric layers and internal electrodes are alternately stacked along a first direction, the internal electrodes being exposed from a side facing a second direction perpendicular to the first direction, and a pair of cover portions covering the capacitance portion from both sides in the first direction, A step of pressing the side surface of the unfired laminate against the sheet member placed on the first elastic member to punch out the sheet member and form a side margin portion on the side surface, The process involves pressing the side margin portion against a rigid plate to form an extended portion in which the sheet member forming the side margin portion is spread out to an area wider than the side surface area, The steps include pressing the side margin portion on which the extended portion is formed against the second elastic member, causing the extended portion to wrap around each of the pair of opposing main surfaces in the laminate along the first direction, forming a protruding portion that projects outward in the first direction, and forming an unfired body, The process of firing the aforementioned body, A step of forming an external electrode on the fired body, A method for manufacturing multilayer ceramic electronic components.

11. The hardness of the second elastic member is lower than the hardness of the first elastic member. A method for manufacturing a multilayer ceramic electronic component according to claim 10.

12. The rigid plate is provided with an extension suppression portion that prevents the sheet member forming the side margin portion from extending toward a pair of opposing end faces in the laminate along a third direction perpendicular to the first and second directions. A method for manufacturing a multilayer ceramic electronic component according to claim 10.

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