Three-terminal multilayer ceramic capacitor

Abstract

Provided is a three-terminal multilayer ceramic capacitor with which improved moisture resistance reliability can be achieved. In a three-terminal multilayer ceramic capacitor 10, each of third and fourth external electrodes 30c, 30d has: a central part 40 having a thickness of 3 μm or more, and first and second convex parts 41a, 41b having a thickness greater than that of the central part 40 and located closer to first and second end surfaces 12e, 12f than the central part 40; and first and second limit points 45a, 45b towards the first and second end surfaces 12e, 12f where, starting from first and second external electrode end parts on the side of the first and second end surfaces 12e, 12f, the thickness first becomes 3 μm or more. Between the first and second limit points 45a, 45b, first and second lead-out end parts 29a, 29b respectively of third and fourth lead-out electrode parts 28b1, 28b2 are positioned.

Description

3-terminal multilayer ceramic capacitor

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

[0002] Patent Document 1 discloses a multilayer feedthrough ceramic capacitor having a typical structure, i.e., a three-terminal multilayer ceramic capacitor. This three-terminal multilayer ceramic capacitor includes a laminate having a pair of main surfaces, a pair of side surfaces, and a pair of end surfaces, and external electrodes disposed on the outer surfaces of the laminate. The laminate is formed by stacking ceramic layers and internal electrode layers. The external electrodes include a pair of end electrodes disposed on the pair of end surfaces of the laminate, a portion of the pair of main surfaces, and a portion of the pair of side surfaces, and a pair of side electrodes disposed on the pair of side surfaces and a portion of the pair of main surfaces of the laminate. Each of the pair of side electrodes in Patent Document 1 has a recessed portion in which the center of the side surface is recessed toward the laminate. The recessed portion reduces the height of swelling when solder is applied. This reduces the size of the solder fillet and the restraining force exerted on the pair of side electrodes via the solder fillet. This reduces stress generated in the laminate, thereby suppressing the occurrence of cracks in the laminate.

[0003] Japanese Patent Application Laid-Open No. 2018-46228

[0004] However, Patent Document 1 does not disclose anything about the positional relationship between the side electrodes and the internal electrode layers. If the internal electrode layers are misaligned with respect to the side electrodes, for example, a part of the internal electrode layer may be positioned outside the side electrodes. In this case, moisture or the like may penetrate the laminate through the part of the internal electrode layer that is not covered by the side electrodes, reducing the moisture resistance reliability of the three-terminal multilayer ceramic capacitor.

[0005] SUMMARY OF THE INVENTION Therefore, a primary object of the present invention is to provide a three-terminal multilayer ceramic capacitor that can improve the moisture resistance reliability, in view of the above-mentioned problems.

[0006] A three-terminal multilayer ceramic capacitor according to the present invention includes a laminate formed by laminating a plurality of ceramic layers and a plurality of internal electrode layers, the laminate having first and second main surfaces opposing each other in a height direction, first end faces and second end faces opposing each other in a length direction perpendicular to the height direction, and first and second side faces opposing each other in a width direction perpendicular to the height direction and the length direction, and external electrodes. The internal electrode layers include a plurality of first internal electrode layers extended to the first end face and the second end face, and a plurality of second internal electrode layers extended to the first side face and the second side face. The external electrodes include a first external electrode disposed on the first end face and connected to the first internal electrode layer, a second external electrode disposed on the second end face and connected to the first internal electrode layer, a third external electrode disposed on the first side face and connected to the second internal electrode layer, and a fourth external electrode disposed on the second side face and connected to the second internal electrode layer. The first internal electrode layer has a first opposing electrode portion opposing the second internal electrode layer, a first lead electrode portion extending from the first opposing electrode portion to the first end face, and a second lead electrode portion extending from the first opposing electrode portion to the second end face. The second internal electrode layer has a second opposing electrode portion opposing the first opposing electrode portion, a third lead electrode portion extending from the second opposing electrode portion to the first side face, and a fourth lead electrode portion extending from the second opposing electrode portion to the second side face.Each of the third external electrode and the fourth external electrode has, in a cross-sectional view along the first main surface and the second main surface, a central portion that is 3 μm or more thick in the width direction relative to each of the first side surface and the second side surface and is located in the center in the length direction, a first protrusion that is larger in thickness in the width direction relative to each of the first side surface and the second side surface than the central portion and is located closer to the first end face than the central portion, and a second protrusion that is larger in thickness in the width direction relative to each of the first side surface and the second side surface than the central portion and is located closer to the second end face than the central portion; The electrode has a first limit point on the first end face side where the widthwise thickness for each of the first side surface and the second side surface becomes 3 μm or more from the end of the first external electrode on the first end face side, and a second limit point on the second end face side where the widthwise thickness for each of the first side surface and the second side surface becomes 3 μm or more from the end of the second external electrode on the second end face side, and the first lead-out end portion on the first end face side and the second lead-out end portion on the second end face side of each of the third lead-out electrode portion and the fourth lead-out electrode portion are located between the first limit point and the second limit point.

[0007] According to the above configuration, the third and fourth external electrodes having the first and second protrusions have a thickness of 3 μm or more in a large range, and therefore the tolerance for misalignment of the second internal electrode layer with respect to the third and fourth external electrodes is large, thereby improving the moisture resistance reliability.

[0008] According to the present invention, it is possible to provide a three-terminal multilayer ceramic capacitor capable of improving the moisture resistance reliability.

[0009] The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention, which proceeds with reference to the accompanying drawings.

[0010] 1 is an external perspective view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention; FIG. 2 is a top view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention; FIG. 3 is a front view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention; FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1; FIG. 5 is a cross-sectional view taken along line V-V in FIG. 1; FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4; FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 4; FIG. 8 is an enlarged photograph of portion α in FIG. 7; FIG. 9 is an enlarged schematic view of portion α in FIG. 7, showing the state of a convex portion and the dimensions of each portion; FIG. 10 is an enlarged schematic view of portion α in FIG. 7, showing the bonding state between a third external electrode and a third lead electrode portion; FIG. 11 is a process diagram showing a first application step of applying a first paste layer to a laminate body, and FIG. 12 is a process diagram showing a second application step of applying a second paste layer to the laminate body; and FIG. 13 is a schematic view for explaining the difference in configuration between a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention and an existing three-terminal multilayer ceramic capacitor.

[0011] 1. Three-Terminal Multilayer Ceramic Capacitor A three-terminal multilayer ceramic capacitor according to an embodiment of the present invention will now be described.

[0012] FIG. 1 is an external perspective view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a top view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 3 is a front view showing an example of a three-terminal multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 1. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 4. FIG. 8 is an enlarged photograph of portion α in FIG. 7. FIG. 9 is an enlarged schematic view of portion α in FIG. 7, showing the state of the protrusions and the dimensions of each portion. FIG. 10 is an enlarged schematic view of portion α in FIG. 7, showing the bonding state between the third external electrode and the third lead electrode portion.

[0013] As shown in FIG. 1, a three-terminal multilayer ceramic capacitor 10 includes, for example, a laminate 12 having a substantially rectangular parallelepiped shape and external electrodes 30 .

[0014] (1) Laminate The laminate 12 has a plurality of laminated ceramic layers 14 and a plurality of internal electrode layers 16 laminated on the ceramic layers 14. The ceramic layers 14 and the internal electrode layers 16 are laminated in the height direction x.

[0015] The laminate 12 has a first main surface 12a and a second main surface 12b that face each other in the height direction x, a first side surface 12c and a second side surface 12d that face each other in the width direction y that is perpendicular to the height direction x, and a first end surface 12e and a second end surface 12f that face each other in the length direction z that is perpendicular to the height direction x and the width direction y. The laminate 12 has rounded corners and ridges. Note that a corner refers to a portion where three adjacent surfaces of the laminate intersect, and a ridge refers to a portion where two adjacent surfaces of the laminate intersect. Furthermore, unevenness may be formed on some or all of the first main surface 12a and the second main surface 12b, the first side surface 12c and the second side surface 12d, and the first end surface 12e and the second end surface 12f. Note that the dimension L of the laminate 12 in the length direction z is not necessarily longer than the dimension W in the width direction y.

[0016] The laminate 12 has an inner layer portion 18, and a first outer layer portion 20a and a second outer layer portion 20b arranged to sandwich the inner layer portion 18 in the stacking direction.

[0017] The inner layer portion 18 includes a plurality of ceramic layers 14 and a plurality of internal electrode layers 16. The inner layer portion 18 includes the internal electrode layer 16 located closest to the first main surface 12a in the stacking direction to the internal electrode layer 16 located closest to the second main surface 12b. The internal electrode layers 16 have first internal electrode layers 16a extending to the first end face 12e and the second end face 12f and second internal electrode layers 16b extending to the first side face 12c and the second side face 12d, and in the inner layer portion 18, the plurality of first internal electrode layers 16a and second internal electrode layers 16b face each other with the ceramic layers 14 interposed therebetween. The inner layer portion 18 generates electrostatic capacitance and essentially functions as a capacitor.

[0018] The first main surface side outer layer portion 20a is located on the first main surface 12a side and is formed from a plurality of ceramic layers 14 located between the first main surface 12a and the outermost surface of the inner layer portion 18 on the first main surface 12a side and a straight line on that outermost surface (an extension line from the outermost surface to the first side surface 12c, the second side surface 12d, the first end face 12e, and the second end face 12f). In other words, the first main surface side outer layer portion 20a is an assembly of a plurality of ceramic layers 14 located between the first main surface 12a and the internal electrode layer 16 closest to the first main surface 12a. The ceramic layers 14 used in the first main surface side outer layer portion 20a may be the same as the ceramic layers 14 used in the inner layer portion 18. Similarly, the second main surface side outer layer portion 20b is located on the second main surface 12b side and is formed from a plurality of ceramic layers 14 located between the second main surface 12b and the outermost surface of the inner layer portion 18 on the second main surface 12b side and a straight line on that outermost surface (an extension line from the outermost surface to the first side surface 12c, the second side surface 12d, the first end face 12e, and the second end face 12f). In other words, the second main surface side outer layer portion 20b is an assembly of a plurality of ceramic layers 14 located between the second main surface 12b and the internal electrode layer 16 closest to the second main surface 12b. The ceramic layers 14 used in the second main surface side outer layer portion 20b may be the same as the ceramic layers 14 used in the inner layer portion 18.

[0019] The laminate 12 also has a first side surface side outer layer portion 22a located on the first side surface 12c side and formed from a plurality of ceramic layers 14 located between the first side surface 12c and the outermost surface of the inner layer portion 18 on the first side surface 12c side. Similarly, the laminate 12 has a second side surface side outer layer portion 22b located on the second side surface 12d side and formed from a plurality of ceramic layers 14 located between the second side surface 12d and the outermost surface of the inner layer portion 18 on the second side surface 12d side. The first side surface side outer layer portion 22a and the second side surface side outer layer portion 22b are also referred to as W gaps or side gaps.

[0020] Furthermore, the laminate 12 has a first end face side outer layer portion 24a located on the first end face 12e side and formed from a plurality of ceramic layers 14 located between the first end face 12e and the outermost surface of the inner layer portion 18 on the first end face 12e side. Similarly, the laminate 12 has a second end face side outer layer portion 24b located on the second end face 12f side and formed from a plurality of ceramic layers 14 located between the second end face 12f and the outermost surface of the inner layer portion 18 on the second end face 12f side. The first end face side outer layer portion 24a and the second end face side outer layer portion 24b are also referred to as L gaps or end gaps.

[0021] The dimensions of the laminate 12 are not particularly limited.

[0022] The ceramic layer 14 can be formed, for example, from a dielectric material as the ceramic material. Examples of such dielectric materials include dielectric ceramics containing components such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3. When the dielectric material is a primary component, it may contain a secondary component, such as a manganese compound, an iron compound, a chromium compound, a cobalt compound, or a nickel compound, in a smaller amount than the primary component, depending on the desired characteristics of the laminate 12.

[0023] The thickness of the ceramic layer 14 after firing is preferably 0.3 μm or more and 5.0 μm or less. The number of laminated ceramic layers 14 is preferably 5 to 2000. Note that this number of ceramic layers 14 is the total number of ceramic layers 14 in the inner layer portion 18 and the first and second outer layer portions 20 a and 20 b.

[0024] The laminate 12 has a plurality of first internal electrode layers 16a and a plurality of second internal electrode layers 16b as the plurality of internal electrode layers 16. The plurality of first internal electrode layers 16a are arranged on the plurality of ceramic layers 14 and extend to the first end face 12e and the second end face 12f. The plurality of second internal electrode layers 16b are arranged on the plurality of ceramic layers 14 and extend to the first side face 12c and the second side face 12d. The plurality of first internal electrode layers 16a and the plurality of second internal electrode layers 16b may be alternately stacked with the ceramic layers 14 interposed therebetween, or a plurality of ceramic layers 14 each having the first internal electrode layer 16a arranged thereon may be stacked, followed by a ceramic layer 14 each having the second internal electrode layer 16b arranged thereon. In this way, the stacking pattern can be changed depending on the capacitance value to be achieved.

[0025] 6 , the first internal electrode layer 16a includes a first opposing electrode portion 26a facing the second internal electrode layer 16b, a first extraction electrode portion 28a extending from the first opposing electrode portion 26a to the surface of the first end face 12e of the laminate 12, and a second extraction electrode portion 28a extending from the first opposing electrode portion 26a to the surface of the second end face 12f of the laminate 12. Specifically, the first extraction electrode portion 28a is exposed on the surface of the first end face 12e of the laminate 12, and the second extraction electrode portion 28a is exposed on the surface of the second end face 12f of the laminate 12. Therefore, the first internal electrode layer 16a is not exposed on the surfaces of the first side face 12c and the second side face 12d of the laminate 12. The first lead-out electrode portion 28a1 is connected to the first external electrode 30a, and the second lead-out electrode portion 28a2 is connected to the second external electrode 30b.

[0026] The shapes of the first opposing electrode portion 26a and the first and second lead electrode portions 28a1 and 28a2 are not particularly limited, but are preferably rectangular, although the corners may be rounded.

[0027] The length in the width direction y of the first extracted electrode portion 28a1 and the second extracted electrode portion 28a2 may be the same as the length in the width direction y of the first opposing electrode portion 26a, or may be shorter. The shape of the first extracted electrode portion 28a1 and the second extracted electrode portion 28a2 may be tapered.

[0028] 7 , the second internal electrode layer 16b is generally cross-shaped and includes a second opposing electrode portion 26b opposing the first opposing electrode portion 26a, a third leading electrode portion 28b extending from the second opposing electrode portion 26b to the surface of the first side surface 12c of the laminate 12, and a fourth leading electrode portion 28b extending from the second opposing electrode portion 26b to the surface of the second side surface 12d of the laminate 12. Specifically, the third leading electrode portion 28b is exposed on the surface of the first side surface 12c of the laminate 12, and the fourth leading electrode portion 28b is exposed on the surface of the second side surface 12d of the laminate 12. Therefore, the second internal electrode layer 16b is not exposed on the surface of the first end surface 12e or the surface of the second end surface 12f of the laminate 12. The third lead electrode portion 28b1 is connected to the third external electrode 30c, and the fourth lead electrode portion 28b2 is connected to the fourth external electrode 30d.

[0029] The second opposing electrode portion 26b and the third and fourth lead electrode portions 28b1 and 28b2 are preferably rectangular in shape, although the corners may be rounded.

[0030] It is preferable that the relationship between the dimension A in the longitudinal direction z connecting the side of the second opposing electrode portion 26b on the first end face 12e side and the side on the second end face 12f side and the dimension B in the longitudinal direction z connecting the side of the third extraction electrode portion 28b1 and the fourth extraction electrode portion 28b2 on the first end face 12e side and the side on the second end face 12f side satisfies A≧B.

[0031] The third extraction electrode portion 28b1 may have a tapered shape in which the width narrows toward the first side surface 12c, and the fourth extraction electrode portion 28b2 may have a tapered shape in which the width narrows toward the second side surface 12d.

[0032] The laminate 12 has a counter electrode region 27. The counter electrode region 27 is a portion where the first counter electrode portion 26a of the first internal electrode layer 16a and the second counter electrode portion 26b of the second internal electrode layer 16b face each other. The counter electrode region 27 is configured as a part of the inner layer portion 18. The counter electrode region 27 is also called a capacitor effective portion.

[0033] The first internal electrode layer 16a and the second internal electrode layer 16b can be made of an appropriate conductive material, such as a metal containing Ni as the main component, Cu, Ag, Pd, Au, or an alloy containing at least one of these metals, such as an Ag-Pd alloy.

[0034] The number of the first internal electrode layers 16a and the second internal electrode layers 16b is not particularly limited, but is preferably, for example, about 10 to 2000 in total.

[0035] The thickness of the first internal electrode layer 16a is not particularly limited, but is preferably, for example, about 0.30 μm or more and 1.0 μm or less. The thickness of the second internal electrode layer 16b is not particularly limited, but is preferably, for example, about 0.30 μm or more and 1.0 μm or less.

[0036] (2) External Electrodes External electrodes 30 are arranged on the first end face 12e side and the second end face 12f side, the first side face 12c side and the second side face 12d side, and the first main face 12a side and the second main face 12b side of the laminate 12.

[0037] The external electrodes 30 include a first external electrode 30a, a second external electrode 30b, a third external electrode 30c, and a fourth external electrode 30d.

[0038] The first external electrode 30a is connected to the first internal electrode layer 16a and is arranged on the surface of the first end face 12e. In this embodiment, the first external electrode 30a extends from the first end face 12e of the laminate 12 and is arranged on part of the first main surface 12a, part of the second main surface 12b, and part of the first side surface 12c, part of the second side surface 12d. In this case, the first external electrode 30a is electrically connected to the first extraction electrode portion 28a1 of the first internal electrode layer 16a. The first external electrode 30a may be arranged only on the surface of the first end face 12e.

[0039] The second external electrode 30b is connected to the first internal electrode layer 16a and is disposed on the surface of the second end face 12f. In this embodiment, the second external electrode 30b extends from the second end face 12f of the laminate 12 and is disposed on part of the first main surface 12a and part of the second main surface 12b, as well as part of the first side surface 12c and part of the second side surface 12d. In this case, the second external electrode 30b is electrically connected to the second extraction electrode portion 28a2 of the first internal electrode layer 16a. The second external electrode 30b may be disposed only on the surface of the second end face 12f.

[0040] The third external electrode 30c is connected to the second internal electrode layer 16b and disposed on the surface of the first side surface 12c. The third external electrode 30c is electrically connected to the third lead electrode portion 28b1 of the second internal electrode layer 16b. The third external electrode 30c may extend from the first side surface 12c of the laminate 12 and be disposed on a part of the first main surface 12a and a part of the second main surface 12b. The third external electrode 30c of this embodiment has a first outer convex portion (an example of a first convex portion) 42a and a second outer convex portion (an example of a second convex portion) 42b that follow the shape of the third underlying electrode layer 32c because the third underlying electrode layer 32c has a first convex portion (an example of a first convex portion) 41a and a second convex portion (an example of a second convex portion) 41b, as described below.

[0041] The fourth external electrode 30d is connected to the second internal electrode layer 16b and is disposed on the surface of the second side surface 12d. The fourth external electrode 30d is electrically connected to the fourth lead electrode portion 28b2 of the second internal electrode layer 16b. The fourth external electrode 30d may extend from the second side surface 12d of the laminate 12 and be disposed on a part of the first main surface 12a and a part of the second main surface 12b. The fourth external electrode 30d of this embodiment has a first outer convex portion (an example of a first convex portion) 42a and a second outer convex portion (an example of a second convex portion) 42b that follow the shape of the fourth underlying electrode layer 32d because the fourth underlying electrode layer 32d has a first convex portion (an example of a first convex portion) 41a and a second convex portion (an example of a second convex portion) 41b, as described below.

[0042] In the laminate 12, capacitance is formed by the first opposing electrode portion 26a of the first internal electrode layer 16a and the second opposing electrode portion 26b of the second internal electrode layer 16b facing each other via the ceramic layer 14. Therefore, capacitance can be obtained between the first external electrode 30a and the second external electrode 30b to which the first internal electrode layer 16a is connected, and the third external electrode 30c and the fourth external electrode 30d to which the second internal electrode layer 16b is connected, and the characteristics of a capacitor are exhibited.

[0043] The external electrode 30 includes a base electrode layer 32 containing a metal component and a glass component, and a plating layer 34 disposed on the surface of the base electrode layer 32 .

[0044] The base electrode layer 32 includes a first base electrode layer 32a, a second base electrode layer 32b, a third base electrode layer 32c, and a fourth base electrode layer 32d.

[0045] The first base electrode layer 32a is connected to the first internal electrode layer 16a and is disposed on the surface of the first end face 12e. The first base electrode layer 32a also extends from the first end face 12e and is disposed on a portion of the first principal surface 12a, a portion of the second principal surface 12b, and a portion of the first side face 12c and a portion of the second side face 12d. The first base electrode layer 32a may be disposed only on the surface of the first end face 12e. The second base electrode layer 32b is connected to the first internal electrode layer 16a and is disposed on the surface of the second end face 12f. The second base electrode layer 32b also extends from the second end face 12f and is disposed on a portion of the first principal surface 12a, a portion of the second principal surface 12b, and a portion of the first side face 12c and a portion of the second side face 12d. The second base electrode layer 32b may be disposed only on the surface of the second end face 12f.

[0046] The third base electrode layer 32c is connected to the second internal electrode layer 16b and is disposed on the surface of the first side surface 12c. The third base electrode layer 32c may also extend from the first side surface 12c and be disposed on part of the first main surface 12a and part of the second main surface 12b. The fourth base electrode layer 32d is connected to the second internal electrode layer 16b and is disposed on the surface of the second side surface 12d. The fourth base electrode layer 32d may also extend from the second side surface 12d and be disposed on part of the first main surface 12a and part of the second main surface 12b.

[0047] Each of the third and fourth base electrode layers 32c and 32d in this embodiment has a convex portion 41 including a first convex portion 41a and a second convex portion 41b, as shown in Figures 6 to 10. The characteristic shapes of the third and fourth base electrode layers 32c and 32d in this embodiment will be described in detail later.

[0048] The base electrode layer 32 includes at least one selected from a baked layer, a conductive resin layer, etc. In the experimental examples described below, the base electrode layer 32 is a baked layer. Hereinafter, each configuration when the base electrode layer 32 is the baked layer or the conductive resin layer will be described.

[0049] (When the base electrode layer is a baking layer) The baking layer contains a glass component and a metal component. The glass component of the baking layer contains at least one selected from B, Si, Ba, Mg, Al, Li, etc. The metal component of the baking layer is, for example, Cu as the main component and at least one selected from Ni, Ag, Pd, an Ag-Pd alloy, Au, etc. The baking layer is formed by applying a conductive paste containing a glass component and a metal component to the laminate 12 and baking it. The baking layer may be formed by simultaneously baking a laminated chip having an internal electrode layer 16 and a ceramic layer 14 with a conductive paste applied to the laminated chip, or by baking a laminated chip having an internal electrode layer 16 and a ceramic layer 14 to obtain the laminate 12 and then baking the conductive paste onto the laminate 12. When the baked layer is formed by simultaneously baking the laminated chip having the internal electrode layers 16 and the ceramic layers 14 and the conductive paste applied to the laminated chip, it is preferable that the baked layer be formed by baking a material to which a dielectric material is added instead of a glass component. The baked layer may be a multi-layered layer.

[0050] When the base electrode layer 32 contains a dielectric material instead of a glass component, it is possible to improve the adhesion between the laminate 12 and the base electrode layer 32. The base electrode layer 32 may contain both a glass component and a dielectric component.

[0051] The dielectric material contained in the base electrode layer 32 may be the same as or different from that of the ceramic layer 14. The dielectric component includes at least one selected from the group consisting of BaTiO, CaTiO, (Ba, Ca)TiO, SrTiO, and CaZrO.

[0052] (When the base electrode layer is a conductive resin layer) When a conductive resin layer is provided as the base electrode layer 32, the conductive resin layer may be disposed on the baked layer so as to cover the baked layer, or may be disposed directly on the laminate 12 without providing a baked layer. The conductive resin layer contains a metal such as conductive particles and a thermosetting resin. The conductive resin layer may completely cover the base electrode layer, or may cover a portion of the base electrode layer.

[0053] Since the conductive resin layer contains a thermosetting resin, it is more flexible than a conductive layer made of, for example, a plating film or a fired conductive paste. Therefore, even if the three-terminal multilayer ceramic capacitor 10 is subjected to a physical shock or a shock due to a thermal cycle, the conductive resin layer functions as a buffer layer and can prevent cracks in the three-terminal multilayer ceramic capacitor 10.

[0054] The metal contained in the conductive resin layer may be Cu-based, Ag, Ni, Sn, Bi, or an alloy containing these. Metal powders whose surfaces are coated with Ag can also be used. When using metal powders whose surfaces are coated with Ag, it is preferable to use Cu, Ni, Sn, Bi, or an alloy powder thereof as the metal powder. The reason for using Ag conductive metal powder as the conductive metal is that Ag has the lowest resistivity of all metals, making it suitable as an electrode material, and Ag is a noble metal that does not oxidize and has high weather resistance. Furthermore, it is possible to use a cheaper base metal while maintaining the above-mentioned properties of Ag.

[0055] Furthermore, the metal contained in the conductive resin layer may be Cu or Ni that has been subjected to an anti-oxidation treatment. The metal contained in the conductive resin layer may be a metal powder whose surface is coated with Sn, Ni, or Cu. When using a metal powder whose surface is coated with Sn, Ni, or Cu, it is preferable to use Ag, Cu, Ni, Sn, Bi, or an alloy powder thereof as the metal powder.

[0056] The metal contained in the conductive resin layer is mainly responsible for the electrical conductivity of the conductive resin layer. Specifically, when the conductive fillers come into contact with each other, a conductive path is formed inside the conductive resin layer.

[0057] The metal contained in the conductive resin layer may be spherical or flat, but it is preferable to use a mixture of spherical metal powder and flat metal powder.

[0058] The resin for the conductive resin layer may be any of various known thermosetting resins, such as epoxy resin, phenoxy resin, phenol resin, urethane resin, silicone resin, polyimide resin, etc. Among these, epoxy resin is one of the most suitable resins, as it has excellent heat resistance, moisture resistance, adhesion, etc.

[0059] The conductive resin layer preferably contains a curing agent together with the thermosetting resin. When an epoxy resin is used as the base resin, various known compounds such as phenol-based, amine-based, acid anhydride-based, imidazole-based, active ester-based, and amide-imide-based compounds can be used as the curing agent for the epoxy resin.

[0060] The conductive resin layer may be a multi-layered layer.

[0061] The plating layer 34 includes a first plating layer 34a, a second plating layer 34b, a third plating layer 34c, and a fourth plating layer 34d. The first plating layer 34a, the second plating layer 34b, the third plating layer 34c, and the fourth plating layer 34d, which are plating layers 34 that can be disposed on the base electrode layer 32, will be described with reference to Figures 4 and 5. The first plating layer 34a, the second plating layer 34b, the third plating layer 34c, and the fourth plating layer 34d each include, for example, at least one selected from Cu, Ni, Sn, Ag, Pd, an Ag-Pd alloy, Au, and the like.

[0062] The first plating layer 34a is disposed so as to cover the first base electrode layer 32a. The second plating layer 34b is disposed so as to cover the second base electrode layer 32b. The third plating layer 34c is disposed so as to cover the third base electrode layer 32c. The fourth plating layer 34d is disposed so as to cover the fourth base electrode layer 32d.

[0063] 6 and 7 , the third and fourth plating layers 34c, 34d each have outer convex portions 42 corresponding to the convex portions 41 of the third and fourth base electrode layers 32c, 32d. That is, the third and fourth plating layers 34c, 34d each have first outer convex portions 42a and second outer convex portions 42b along the shapes of the first convex portions 41a and second convex portions 41b of the third and fourth base electrode layers 32c. Because the third and fourth plating layers 34c, 34d form the outer surfaces of the third and fourth external electrodes 30c, 30d, the first and second outer convex portions 42a, 42b of the third and fourth plating layers 34c, 34d become the first and second outer convex portions 42a, 42b of the third and fourth external electrodes 30c, 30d.

[0064] The first plating layer 34 a, the second plating layer 34 b, the third plating layer 34 c, and the fourth plating layer 34 d may each be formed of a plurality of layers. In this case, the plating layer 34 preferably has a two-layer structure including a lower plating layer formed on the base electrode layer 32 by Ni plating and an upper plating layer formed on the lower plating layer by Sn plating.

[0065] That is, the first plating layer 34a has a first lower plating layer and a first upper plating layer located on the surface of the first lower plating layer. The second plating layer 34b has a second lower plating layer and a second upper plating layer located on the surface of the second lower plating layer. Similarly, the third plating layer 34c has a third lower plating layer and a third upper plating layer located on the surface of the third lower plating layer. The fourth plating layer 34d has a fourth lower plating layer and a fourth upper plating layer located on the surface of the fourth lower plating layer.

[0066] The lower plating layer made of Ni is used to prevent the base electrode layer 32 from being eroded by solder when mounting the three-terminal multilayer ceramic capacitor 10, and the upper plating layer made of Sn is used to improve the wettability of the solder when mounting the three-terminal multilayer ceramic capacitor 10, thereby facilitating mounting. The thickness of each plating layer is preferably 2.0 μm or more and 15.0 μm or less.

[0067] Next, the shapes of the third and fourth base electrode layers 32c, 32d will be further described. Because the third and fourth base electrode layers 32c, 32d have substantially the same shape, only the third base electrode layer 32c will be described, and a description of the fourth base electrode layer 32d will be omitted or simplified. Figures 8 to 10 show the cross-sectional shapes of the laminate 12 and the third base electrode layer 32c in a cross-sectional view taken along the first and second principal surfaces 12a, 12b. Figures 8 to 10 show, for example, an LW cross section (a cross section including the length direction z and the width direction y) at ½T, where T is the dimension of the three-terminal multilayer ceramic capacitor 10 in the height direction x.

[0068] 8 to 10 , a third base electrode layer 32c is formed on the first side surface 12c of the laminate 12 in the LW cross section. The third base electrode layer 32c has a central portion 40 and a protruding portion 41. The central portion 40 is the third base electrode layer 32c in a portion located at point M, which is the center in the longitudinal direction z of the third base electrode layer 32c, and has a thickness of 3 μm or more in the width direction y relative to the first side surface 12c. The protruding portion 41 includes a first protruding portion 41a and a second protruding portion 41b.

[0069] The first convex portion 41a is a portion of the third base electrode layer 32c whose thickness in the width direction y relative to the first side surface 12c is greater than that of the central portion 40, and is located at point Q1, which is closer to the first end face 12e than the central portion 40.

[0070] The second convex portion 41b is a portion whose thickness in the width direction y relative to the first side surface 12c is greater than that of the central portion 40, and is the third underlying electrode layer 32c located at point Q2, which is closer to the second end face 12f than the central portion 40.

[0071] At least one of the first and second protrusions 41a and 41b has the greatest thickness in the third base electrode layer 32c.

[0072] The third base electrode layer 32c has a limit point 45 where the thickness becomes 3 μm or more from the base electrode end 35, which is the end of the third base electrode layer 32c. In FIG. 9 , the portion of the third base electrode layer 32c where the thickness in the width direction y relative to the first side surface 12c is 3 μm is indicated as h (= 3 μm). The base electrode end 35 includes a first base electrode end 35a on the first end face 12e side of the third base electrode layer 32c and a second base electrode end 35b on the second end face 12f side. The first base electrode end (corresponding to the first external electrode end) 35a is the end of the third base electrode layer 32c on the first end face 12e side. The second base electrode end (corresponding to the second external electrode end) 35b is the end of the third base electrode layer 32c on the second end face 12f side. The limit points 45 include a first limit point 45a and a second limit point 45b.

[0073] The first limit point 45a is a portion of the third base electrode layer 32c located at point P1 on the first end face 12e side. At point P1, the first limit point 45a is the point where the thickness in the width direction y relative to the first side face 12c becomes 3 μm or more for the first time from the first base electrode end 35a (point R1).

[0074] The second limit point 45b is a portion of the third base electrode layer 32c located at point P2 on the second end face 12f side. At point P2, the second limit point 45b is the point where the thickness in the width direction y relative to the first side face 12c becomes 3 μm or more for the first time from the second base electrode end 35b (point R2).

[0075] The third extraction electrode portion 28b is located between the first limit point 45a and the second limit point 45b in the laminate 12. Specifically, the extraction ends 29 (the first extraction end 29a on the first end face 12e side and the second extraction end 29b on the second end face 12f side) of the third extraction electrode portion 28b are located between the first limit point 45a and the second limit point 45b in the laminate 12.

[0076] The third underlying electrode layer 32c can be said to have a central region 50c, a first end face side region 50a, and a second end face side region 50b. The central region 50c includes the central portion 40 and is located between the first convex portion 41a and the second convex portion 41b. The first end face side region 50a is located on the first end face 12e side of the central region 50c. The second end face side region 50b is located on the second end face 12f side of the central region 50c. The first convex portion 41a is located at the boundary between the central region 50c and the first end face side region 50a. The second convex portion 41b is located at the boundary between the central region 50c and the second end face side region 50b. The first limit point 45a is located within the first end face side region 50a. The second limit point 45b is located within the second end face side region 50b. The first and second protrusions 41a and 41b are thicker than the central portion 40 and are the thickest in the third base electrode layer 32c. The thickness of the third base electrode layer 32c decreases from the first protrusion 41a to the first base electrode end 35a, but because the first protrusion 41a is thicker, the first limit point 45a can be located closer to the first end face 12e than the first protrusion 41a. The thickness of the third base electrode layer 32c decreases from the second protrusion 41b to the second base electrode end 35b, but because the second protrusion 41b is thicker, the second limit point 45b can be located closer to the second end face 12f than the second protrusion 41b.

[0077] As shown in Figure 9, if the distance from the first base electrode end 35a (point R1) to the first limit point 45a (point P1) and the distance from the second base electrode end 35b (point R2) to the second limit point 45b (point P2) are f, and the width in the longitudinal direction z of the third base electrode layer 32c is e (the distance from point R1 to point R2), it is preferable that 0.01≦f / e≦0.09.

[0078] Furthermore, when the distance a1 from the first base electrode end 35a (point R1) to the first convex portion 41a (point Q1) and the distance a2 from the second base electrode end 35b (point R2) to the second convex portion 41b (point Q2) are a, it is preferable that 0.10≦a / e≦0.30.

[0079] Furthermore, if the thickness d1 of the first convex portion 41a in the width direction y relative to the first side surface 12c and the thickness d2 of the second convex portion 41b in the width direction y relative to the first side surface 12c are d, and the thickness of the central portion 40 in the width direction y relative to the first side surface 12c is c, it is preferable that 0.65≦c / d≦0.97.

[0080] The thickness c of the central portion 40 is preferably 8.0 μm≦c≦18.0 μm.

[0081] The thickness d of the first and second convex portions 41a and 41b is preferably in the range of 10.0 μm≦d≦21.0 μm.

[0082] The width e of the third underlying electrode layer 32c is preferably 200 μm≦e≦600 μm, and more preferably 230 μm≦e≦390 μm.

[0083] Next, the alloy layer 62 and glass ratio formed between the third base electrode layer 32c and the third lead electrode portion 28b1 will be described. As shown in FIG. 10 , the third base electrode layer 32c and the third lead electrode portion 28b1 are in contact with and bonded to each other at a contact interface 60a on the first side surface 12c. At the contact interface 60a, Ni in the third lead electrode portion 28b1 and Cu in the third base electrode layer 32c interdiffuse to form an alloy layer 62. This alloy layer 62 is denser than the third lead electrode portion 28b1 and the third base electrode layer 32c themselves, improving the bonding strength between the third lead electrode portion 28b1 and the third base electrode layer 32c.

[0084] The third base electrode layer 32c has a contact region 60 and a non-contact region 61. The contact region 60 includes a contact interface 60a and an out-of-interface region 60b. The contact interface 60a is the interface where the third base electrode layer 32c is in contact with the third lead electrode portion 28b1. An alloy layer 62 is formed at the contact interface 60a. The contact region 60 is a portion of the third base electrode layer 32c extending from the contact interface 60a to the outside in the width direction y. The out-of-interface region 60b is a region of the contact region 60 excluding the contact interface 60a. In other words, the out-of-interface region 60b is a region of the contact region 60 excluding the region where the alloy layer 62 is formed. The non-contact region 61 is a portion of the third base electrode layer 32c other than the contact region 60, and is a region where the third base electrode layer 32c is not in contact with the third lead electrode portion 28b1. The non-contact region 61 has a first non-contact region 61a located closer to the first end face 12e than the contact region 60, and a second non-contact region 61b located closer to the second end face 12f than the contact region 60.

[0085] 10, the contact region 60 is located between the first protrusion 41a and the second protrusion 41b. However, as described above, the third extraction electrode portion 28b1 only needs to be positioned between the first limit point 45a and the second limit point 45b, and therefore the contact region 60 only needs to be formed between the first limit point 45a and the second limit point 45b. It is preferable that the central portion 40 is included in the contact region 60.

[0086] Here, the out-of-interface region glass ratio, which is the ratio of the glass component to the components constituting the third base electrode layer 32c in the out-of-interface region 60b, is defined as g1. Furthermore, the non-contact region glass ratio, which is the ratio of the glass component to the components constituting the third base electrode layer 32c in the non-contact region 61, is defined as g2. In this case, the out-of-interface region glass ratio g1 > the non-contact region glass ratio g2. More specifically, if the first non-contact region glass ratio, which is the ratio of the glass component to the components constituting the third base electrode layer 32c in the first non-contact region 61a, is defined as g2a, and the second non-contact region glass ratio, which is the ratio of the glass component to the components constituting the third base electrode layer 32c in the second non-contact region 61b, is defined as g2b, then the out-of-interface region glass ratio g1 > the first non-contact region glass ratio g2a and the second non-contact region glass ratio g2b. The out-of-interface region glass ratio g1 is preferably 1.4 to 1.7 times the non-contact region glass ratio g2 (average of the first non-contact region glass ratio g2a and the second non-contact region glass ratio g2b).

[0087] Next, the fourth base electrode layer 32d has a similar configuration to the third base electrode layer 32c and will be briefly described below. The fourth base electrode layer 32d has a central portion 40 whose thickness relative to the second side surface 12d is 3 μm or more, and a convex portion 41 including a first convex portion 41a and a second convex portion 41b. The fourth base electrode layer 32d also has a first limit point 45a where the thickness relative to the second side surface 12d becomes 3 μm or more from the first base electrode end portion 35a of the fourth base electrode layer 32d, and a second limit point 45b where the thickness relative to the second side surface 12d becomes 3 μm or more from the second base electrode end portion 35b of the fourth base electrode layer 32d. In the laminate 12, a fourth extraction electrode portion 28b2 is located between the first limit point 45a and the second limit point 45b. Specifically, in the laminate 12, the first extraction end 29a on the first end face 12e side and the second extraction end 29b on the second end face 12f side of the fourth extraction electrode portion 28b2 are located between the first limit point 45a and the second limit point 45b.

[0088] In the fourth base electrode layer 32d, the distance f from the first and second base electrode ends 35a, 35b (points R1, R2) to the first and second limit points 45a, 45b (points P1, P2), the width e (distance from point R1 to point R2) in the longitudinal direction z of the fourth base electrode layer 32d, the distance a from the first and second base electrode ends 35a, 35b (points R1, R2) to the first and second convex portions 41a, 41b (points Q1, Q2), the thickness d in the width direction y of the first and second convex portions 41a, 41b with respect to the second side surface 12d, the thickness c in the width direction y of the central portion 40 with respect to the second side surface 12d, and the out-of-interface region glass ratio g1 and the non-contact region glass ratio g2 in the fourth base electrode layer 32d are the same as those described above for the third base electrode layer 32c.

[0089] (3) Dimensions of the Three-Terminal Multilayer Ceramic Capacitor The dimension of the three-terminal multilayer ceramic capacitor 10 including the laminate 12 and the first external electrodes 30a to fourth external electrodes 30d in the length direction z is defined as dimension L, the dimension in the height direction x is defined as dimension T, and the dimension in the width direction y is defined as dimension W. The dimensions of the three-terminal multilayer ceramic capacitor 10 are not particularly limited, but are preferably such that the dimension L in the length direction z is 1.05 mm to 1.35 mm, the dimension T in the height direction x is 0.45 mm to 0.90 mm, and the dimension W in the width direction y is 0.60 mm to 0.95 mm. The dimensions of the three-terminal multilayer ceramic capacitor 10 can be measured using a microscope.

[0090] 2. Method for Manufacturing a Three-Terminal Multilayer Ceramic Capacitor Next, a method for manufacturing a three-terminal multilayer ceramic capacitor will be described.

[0091] First, a dielectric sheet for the ceramic layer and a conductive paste for the internal electrode layer are prepared. The dielectric sheet and the conductive paste for the internal electrode layer contain a binder and a solvent. The binder and the solvent may be known.

[0092] Then, a conductive paste for the internal electrode layers is printed in a predetermined pattern on the dielectric sheet by, for example, gravure printing, screen printing, etc. In this way, a dielectric sheet on which the pattern of the first internal electrode layer is formed, and a dielectric sheet on which the pattern of the second internal electrode layer is formed are prepared.

[0093] Next, a predetermined number of dielectric sheets for outer layers, on which the pattern of the internal electrode layer is not printed, are laminated to form a portion that will become the second main surface side outer layer portion on the second main surface side. Then, a dielectric sheet on which the pattern of the first internal electrode layer is printed and a dielectric sheet on which the pattern of the second internal electrode layer is printed are sequentially laminated on the portion that will become the second main surface side outer layer portion so as to form the structure of the present invention, to form a portion that will become the internal layer portion. A predetermined number of dielectric sheets for outer layers, on which the pattern of the internal electrode layer is not printed, are laminated on this portion that will become the internal layer portion, to form a portion that will become the first main surface side outer layer portion on the first main surface side. In this way, a laminated sheet is produced.

[0094] Next, the laminated sheets are pressed in the lamination direction by means of a hydrostatic press or the like to produce a laminated block.

[0095] The laminated block is then cut to a predetermined size to obtain laminated chips, which may have rounded corners and ridges by barrel polishing or the like.

[0096] The cut-out laminated chips are then fired to produce a laminate. The firing temperature is preferably 900° C. or higher and 1400° C. or lower, although this depends on the materials of the ceramic layers and internal electrode layers.

[0097] Next, a third base electrode layer 32c of the third external electrode 30c is formed on the first side surface 12c of the laminate 12 obtained by firing, and a fourth base electrode layer 32d of the fourth external electrode 30d is formed on the second side surface 12d of the laminate 12.

[0098] The third and fourth base electrode layers 32c, 32d having the first convex portions 41a and the second convex portions 41b can be formed by applying the external electrode paste 70 twice using, for example, a roller transfer method. In Fig. 11, (a) is a process diagram showing a first application step of applying a first paste layer to the laminate, and (b) is a process diagram showing a second application step of applying a second paste layer to the laminate.

[0099] As shown in FIG. 11( a), the first coating step is performed by a first coating mechanism 90. The first coating mechanism 90 includes a first supply roller 91 having a plurality of first recesses 92, a first coating roller 93, a first paste tank 94 in which the external electrode paste 70 is stored, and a first carrier tape 95 that transports the laminate 12. As the first supply roller 91 rotates, a portion of the roller is immersed in the external electrode paste 70 in the first paste tank 94, and the external electrode paste 70 is sequentially applied to the plurality of first recesses 92. The first recess 92 has a shape that allows a first first paste layer 71 to be formed on the first side surface 12c or the second side surface 12d of the laminate 12. In the example of FIG. 11( a), the first recess 92 is formed from a single recess having a flat bottom, and the first recess 92 forms the first paste layer 71 as a continuous layer. The external electrode paste 70 in the first recess 92 of the first supply roller 91 is transferred as a first paste layer 71 onto the outer peripheral surface of the rotating first application roller 93. Then, the first paste layer 71 is applied evenly onto the first side surface 12 c or the second side surface 12 d of each of the plurality of laminates 12 that are sequentially transported along the first carrier tape 95.

[0100] 11(b), a second coating step is performed by a second coating mechanism 90a. The second coating mechanism 90a includes a second supply roller 91a having a plurality of second recesses 92a, a second coating roller 93a, a second paste tank 94a in which the external electrode paste 70 is stored, and a second carrier tape 95a that transports the laminate 12 on which the first paste layer 71 has been coated. As the second supply roller 91a rotates, a portion of the roller is immersed in the external electrode paste 70 in the second paste tank 94a, and the external electrode paste 70 is sequentially applied to the plurality of second recesses 92a. The second recesses 92a have a shape that allows a second second paste layer 72 to be formed on the first paste layer 71 of the laminate 12. In the example of FIG. 11( b), the second recesses 92a are formed by dividing one recess into two along the rotational direction, and the second recesses 92a form the second paste layer 72 as two layers divided along the rotational direction. The external electrode paste 70 in the second recesses 92a of the second supply roller 91a is transferred as the second paste layer 72 to the outer peripheral surface of the rotating second application roller 93a. The second paste layer 72 is then applied onto the first paste layer 71 of the multiple laminates 12 being sequentially transported along the second carrier tape 95a. As a result, the second paste layer 72 divided into two is applied to both ends of the first paste layer 71. The paste layer is thick where the first paste layer 71 and the second paste layer 72 are stacked, and is thin where only the first paste layer 71 is present between the second paste layer 72 and the second paste layer 72. When the paste having such a shape is fired, the base electrode layer 32 is formed having first protrusions 41a and second protrusions 41b that are thicker at both ends than at the center.

[0101] Alternatively, the external electrode paste 70 can be applied to the laminate 12 by extruding it through slits of a desired shape.

[0102] The external electrode paste 70 may be any paste capable of forming the third and fourth base electrode layers 32c, 32d having the shapes described above. Furthermore, the external electrode paste 70 is preferably one that can suppress swelling of the central portion compared to the edge portions when the base electrode layer 32 is formed using the external electrode paste 70. For example, the external electrode paste 70 contains a resin, a metal filler, and a solvent. This suppresses swelling of the central portion 40 of the third and fourth base electrode layers 32c, 32d, suppresses an increase in the dimensions of the three-terminal multilayer ceramic capacitor 10, thereby enabling a thinner and more compact design, and also makes it easier to form the first and second protrusions 41a, 41b.

[0103] The type of resin is not particularly limited as long as the desired effect is not impaired. Various resins that have conventionally been blended into external electrode paste 70 can be used as the resin without any particular limitation. Examples of preferred resins include cellulose-based resins, acrylic-based resins, and butyral-based resins. It is particularly preferred that the resin contains a cellulose-based resin, as this makes it easier to obtain an external electrode paste 70 with a viscosity suitable for forming external electrodes. It is also preferred that the resin contains a copolymer resin having blocks derived from a cellulose-based resin. Such a copolymer resin may be a block copolymer or a graft copolymer.

[0104] The cellulose-based resin is, for example, at least one of ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, trityl cellulose, acetyl cellulose, carboxymethyl cellulose, and nitrocellulose.

[0105] The acrylic resin is, for example, a homopolymer or copolymer of one or more monomers selected from isobutyl methacrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate.

[0106] The metal filler is made of the metal that constitutes the external electrode. The type of metal that constitutes the metal filler is appropriately selected depending on the type of metal that constitutes the external electrode. Because of their excellent conductivity and the ease of obtaining metal fillers with the desired particle size, the metal is preferably copper (Cu), silver (Ag), nickel (Ni), or an alloy containing these metals. The alloy containing these metals preferably contains one or more selected from the group consisting of copper (Cu), silver (Ag), and nickel (Ni). It is also preferable that the alloy containing these metals contains tin (Sn).

[0107] The solvent is added as a component that dissolves the resin, disperses the metal filler, and imparts fluidity to the external electrode paste 70 .

[0108] The solvent includes one or more first solvents and one or more second solvents. The mass ratio of the first solvent and the mass ratio of the second solvent to the mass of the solvent are each 40 mass% or more. The lowest boiling point T of the one or more second solvents under atmospheric pressure is Hl is the highest boiling point T among the boiling points of one or more first solvents under atmospheric pressure. Lh The highest boiling point T of the one or more second solvents at atmospheric pressure is 10°C or more higher. Hh But, T Hl The lowest boiling point T of the first solvent at atmospheric pressure is +10°C or less. Ll But, T Lh The solvent may contain a sub-solvent in addition to the first and second solvents. The boiling point of the sub-solvent under atmospheric pressure is (T Ll -10) ° C or less, (T Lh +10)℃ (T Hl -10) ° C or less, or (T Hh +10) °C.

[0109] Specific examples of suitable solvents include Texanol, propylene glycol monophenyl ether, butyl carbitol, terpene solvents, diethylene glycol, carbitol acetate, butyl carbitol acetate, benzyl alcohol, methyl propylene diglycol, diphenyl ether, and ethylene glycol.

[0110] The external electrode paste 70 contains a resin containing at least a partially copolymerized ethyl cellulose resin and an acrylic resin, a Cu filler, and a solvent. The interfacial tension between the resin and the solvent is preferably 15 mN / m or more. The resin and solvent are as described above.

[0111] Next, a manufacturing method will be described when the base electrode layer 32 is a baked layer or a conductive resin layer. (When the base electrode layer is a baked layer) When forming baked layers as the third base electrode layer 32c and the fourth base electrode layer 32d, a conductive paste (external electrode paste 70) containing a glass component and a metal component is applied. The conductive paste can be applied, for example, by the first and second application steps described above. A baking process is then performed to form the base electrode layer. The baking temperature at this time is preferably 700°C or higher and 900°C or lower. In the experimental examples described below, the base electrode layer 32 was formed as a baked layer.

[0112] In the case of the roller transfer method, when the base electrode layer 32 is formed not only on the first side surface 12 c and the second side surface 12 d but also on a part of the first main surface 12 a and a part of the second main surface 12 b, it is possible to form the base electrode layer 32 on a part of the first main surface 12 a and a part of the second main surface 12 b by increasing the pressing pressure when the external electrode paste 70 is roller transferred. Also, in the case of a method in which the external electrode paste 70 is applied by extruding it through a slit, it is possible to form the base electrode layer 32 not only on the first side surface 12 c and the second side surface 12 d but also on a part of the first main surface 12 a and a part of the second main surface 12 b by increasing the amount of the external electrode paste 70 extruded.

[0113] (When the Base Electrode Layer is a Conductive Resin Layer) When the third base electrode layer 32c and the fourth base electrode layer 32d are formed of a conductive resin layer, the conductive resin layer can be formed by the following method. The conductive resin layer may be formed on the surface of a baked layer, or the conductive resin layer may be formed alone directly on the laminate 12 without forming a baked layer.

[0114] The conductive resin layer is formed by applying a conductive resin paste (external electrode paste 70) containing a thermosetting resin and a metal component onto the baking layer or the laminate 12. The conductive resin paste can be applied, for example, by the first and second application steps described above. Then, a heat treatment is performed at a temperature of 250°C to 550°C to thermally cure the resin and form a conductive resin layer. The heat treatment is preferably performed in an N2 atmosphere. Furthermore, to prevent the resin from scattering and the various metal components from oxidizing, it is preferable to keep the oxygen concentration below 100 ppm.

[0115] The conductive resin paste can be applied using a method similar to the method of forming the base electrode layer 32 as a baked layer, for example, a method of applying the conductive resin paste by extruding it through a slit or a roller transfer method.

[0116] Next, the first base electrode layer 32a of the first external electrode 30a is formed on the first end face 12e of the fired laminate, and the second base electrode layer 32b of the second external electrode 30b is formed on the second end face 12f. As with the third and fourth base electrode layers 32c and 32d, when forming baked layers as the first and second base electrode layers 32a and 32b, a conductive paste containing a glass component and a metal component is applied, followed by a baking process to form the base electrode layers. The baking temperature is preferably 700°C or higher and 900°C or lower. The conductive paste can be applied to both end faces of the laminate by, for example, a dipping method or a screen printing method. In the experimental examples described below, the first and second base electrode layers 32a and 32b were formed using a dipping method so as to extend not only to the first end face 12e and the second end face 12f, but also to a portion of the first main surface 12a, a portion of the second main surface 12b, a portion of the first side surface 12c, and a portion of the second side surface 12d.

[0117] In the baking process, the third base electrode layer 32c, the fourth base electrode layer 32d, the first base electrode layer 32a, and the second base electrode layer 32b may be baked simultaneously, or they may be baked separately on both side surfaces 12c and 12d and both end surfaces 12e and 12f.

[0118] When the base electrode layer is formed as a baking layer, the baking layer may contain a dielectric component. In this case, the dielectric component may be contained instead of the glass component, or both may be contained.

[0119] The dielectric component is preferably, for example, the same dielectric material as the laminate. When the baked layer contains the dielectric component, it is preferable to apply a conductive paste to the pre-fired laminated chip, and then simultaneously bake (fire) the pre-fired laminated chip and the conductive paste applied to the pre-fired laminated chip to form a laminate with a baked layer. The baking temperature (baking temperature) at this time is preferably 900°C or higher and 1400°C or lower.

[0120] Next, a plating layer 34 is formed. The plating layer 34 may be formed on the surface of the base electrode layer 32 or directly on the laminate 12. In the experimental examples described below, the plating layer 34 was formed on the surface of the base electrode layer 32. More specifically, a Ni plating layer is formed on the base electrode layer 32 as the lower plating layer, and a Sn plating layer is formed as the upper plating layer. The Ni plating layer and the Sn plating layer are formed sequentially, for example, by barrel plating. Either electrolytic plating or electroless plating may be used for the plating process. However, electroless plating has the disadvantage of requiring pretreatment using a catalyst or the like to improve the plating deposition rate, which complicates the process. Therefore, electrolytic plating is usually preferred.

[0121] In the manner described above, the three-terminal multilayer ceramic capacitor 10 according to this embodiment is manufactured.

[0122] 3. Effects and Advantages The effects and advantages of the three-terminal multilayer ceramic capacitor 10 will now be described.

[0123] (1) Effects of Having the First and Second Protrusions According to the above configuration, the third and fourth base electrode layers 32c, 32d having the first and second protrusions 41a, 41b have a large range of thicknesses of 3 μm or more. Therefore, the tolerance for misalignment of the second internal electrode layer 16b with respect to the third and fourth base electrode layers 32c, 32d is large, and moisture resistance reliability can be improved. This will be explained in detail below.

[0124] According to the above configuration, the third and fourth base electrode layers 32c, 32d have a first protrusion 41a on the first end face 12e side and a second protrusion 41b on the second end face 12f side, which are thicker than the central portion 40 having a thickness of 3 μm or more. Therefore, the third and fourth base electrode layers 32c, 32d having the first and second protrusions 41a, 41b have a greater thickness on the first and second end faces 12e, 12f side than the third and fourth base electrode layers 32c, 32d not having the first and second protrusions 41a, 41b, which are, for example, thickest at the central portion 40 and gradually decrease in thickness toward the first and second end faces 12e, 12f. This point will be further explained using FIG. 12 .

[0125] 12 is a schematic diagram illustrating the difference in configuration between the three-terminal multilayer ceramic capacitor according to the embodiment of the present invention and an existing three-terminal multilayer ceramic capacitor. In FIG. 12, the third base electrode layer 32c according to the embodiment is indicated by a solid line, and the third base electrode layer of the existing three-terminal multilayer ceramic capacitor (hereinafter referred to as the existing base electrode layer) is indicated by a dashed line. The third base electrode layer 32c according to the embodiment has a central portion 40 at point M and first and second convex portions 41a, 41b at points Q1 and Q2, and the first and second convex portions 41a, 41b have a thickness d. The thickness d of the first and second convex portions 41a, 41b is the largest within the third base electrode layer 32c. The third base electrode layer 32c according to the present embodiment has a first limit point 45a at point P1 between the first convex portion 41a and the end 35a of the first base electrode at point R1, and a second limit point 45b at point P2 between the second convex portion 41b and the end 35b of the second base electrode at point R2. As described above, the thickness h of the first and second limit points 45a, 45b is 3 μm.

[0126] On the other hand, the existing base electrode layer has one apex 80 at point M. The thickness at apex 80 is d, which is the same as that of the first and second protrusions 41a, 41b. The existing base electrode layer also has first and second base electrode ends at points R1 and R2. According to FIG. 12 , in the existing base electrode layer, the points S1 and S2 of the reference limit point 81 (first reference limit point 81a, second reference limit point 81b) are the points where the thickness of the existing base electrode layer first becomes 3 μm or more from the first and second base electrode ends (points R1, R2).

[0127] The range from the first limit point 45a to the second limit point 45b of the third base electrode layer 32c according to this embodiment is from point P1 to point P2, whereas the range from the first reference limit point 81a to the second reference limit point 81b of the existing base electrode layer is from point S1 to point S2. The range from point P1 to point P2 is greater than the range from point S1 to point S2. This is because the third base electrode layer 32c according to this embodiment has first and second convex portions 41a and 41b, and therefore the gradient at which the thickness increases from the first and second base electrode ends 35a and 35b is greater than that of the existing base electrode layer. The same can be said for the fourth base electrode layer 32d.

[0128] As described above, in the third and fourth base electrode layers 32c, 32d according to this embodiment, the first limit point 45a, where the thickness becomes 3 μm or more from the first base electrode end 35a, is located closer to the first end face 12e, and the second limit point 45b, where the thickness becomes 3 μm or more from the second base electrode end 35b, is located closer to the second end face 12f. Because the range from the first limit point 45a to the second limit point 45b, where the thickness is 3 μm or more, is thus large, it is easy to position the first and second lead ends 29a, 29b within the range between the first limit point 45a and the second limit point 45b. In other words, the tolerance for misalignment of the second internal electrode layer 16b with respect to the third and fourth base electrode layers 32c, 32d can be increased. Therefore, it is possible to prevent at least a portion of the third and fourth extraction electrode portions 28b1, 28b2 from being positioned out of position, such as being positioned outside the third and fourth base electrode layers 32c, 32d, and as a result, it is possible to prevent moisture from penetrating into the laminate 12 through the third and fourth extraction electrode portions 28b1, 28b2, thereby improving moisture resistance reliability.

[0129] (2) Effects of 0.01≦f / e≦0.09 It is preferable that the distance f from the first and second base electrode ends 35a, 35b to the first and second limit points 45a, 45b be small, in the range of 0.01 to 0.09, relative to the width e of the third and fourth base electrode layers 32c, 32d. This is thought to be because the third and fourth base electrode layers 32c, 32d are formed by rising with a large slope from the first and second base electrode ends 35a, 35b to a thickness of 3 μm or more so as to have the first and second protrusions 41a, 41b. Therefore, since the range from the first limit point 45a to the second limit point 45b, where the thickness is 3 μm or more, is large, the tolerance for misalignment of the second internal electrode layer 16b with respect to the third and fourth base electrode layers 32c, 32d is large. Therefore, it is possible to further prevent the third and fourth lead electrode portions 28b1, 28b2 from being misaligned with respect to the third and fourth base electrode layers 32c, 32d, and it is possible to further improve the moisture resistance reliability.

[0130] (3) Effects of 0.10≦a / e≦0.30 It is preferable that the distance a from the first and second base electrode ends 35a, 35b to the first and second protrusions 41a, 41b be small, at 0.10 or more and 0.30 or less, relative to the width e of the third and fourth base electrode layers 32c, 32d. This makes it possible to make the distance f from the first and second base electrode ends 35a, 35b to the first and second limit points 45a, 45b at which the thickness becomes 3 μm or more small relative to the width e of the third and fourth base electrode layers 32c, 32d. Therefore, since the range from the first limit point 45a to the second limit point 45b is large, it is possible to further prevent the third and fourth extraction electrodes 28b1, 28b2 from being misaligned with the third and fourth base electrode layers 32c, 32d, and further improve moisture resistance reliability.

[0131] (4) Effects of 0.65≦c / d≦0.97 It is preferable that c / d is in the above range. Therefore, the third and fourth base electrode layers 32c, 32d can have the first convex portion 41a and the second convex portion 41b in positions close to the first and second end faces 12e, 12f, respectively. This allows the range from the first limit point 45a to the second limit point 45b, where the thickness is 3 μm or more, to be widened. This further prevents the third and fourth extraction electrode portions 28b1, 28b2 from being misaligned with respect to the third and fourth base electrode layers 32c, 32d, thereby further improving moisture resistance reliability.

[0132] (5) Effects of 8.0 μm≦c≦18.0 μm It is preferable that the thickness c of the central portion 40 be within the above range. Therefore, the thickness c can be set to 3 μm or more to ensure moisture-resistant reliability, while preventing the thickness c from becoming too large. This makes it possible to suppress an increase in the dimensions of the three-terminal multilayer ceramic capacitor 10, thereby achieving a thinner and more compact design, while ensuring moisture-resistant reliability.

[0133] (6) Effects of 10.0 μm≦d≦21.0 μm It is preferable that the thickness d of the first and second protrusions 41 a, 41 b be within the above range. The thickness d is set to 3 μm or more to ensure moisture-resistant reliability, and the range from the first limit point 45 a to the second limit point 45 b can be widened while preventing the thickness d from becoming too large. This makes it possible to suppress an increase in the dimensions of the three-terminal multilayer ceramic capacitor 10 and achieve a thinner and more compact design while ensuring moisture-resistant reliability.

[0134] (7) Effects of Out-of-Interface Region Glass Ratio g1 > Non-Contact Region Glass Ratio g2 At the contact interface 60a between the third and fourth base electrode layers 32c, 32d and the third and fourth lead electrodes 28b, 28b, during firing, the metal components of the third and fourth base electrode layers 32c, 32d react with the metal components of the third and fourth lead electrodes 28b, 28b, forming an alloy layer 62. The formation of the alloy layer 62 improves the bonding strength between the third and fourth base electrode layers 32c, 32d and the third and fourth lead electrodes 28b, 28b. At this time, the glass components of the third and fourth base electrode layers 32c, 32d are concentrated in the out-of-interface region 60b, which is a portion of the third and fourth base electrode layers 32c, 32d that is spaced apart from the contact interface 60a in the width direction y, to form a dense glass layer. Therefore, the out-of-interface region glass ratio g1 is higher than the non-contact region glass ratio g2. Because the out-of-interface region glass ratio g1 is relatively large, the presence of glass in the out-of-interface region 60b tends to facilitate sintering during firing. Therefore, the protrusion in the contact region 60 is suppressed, thereby suppressing an increase in the dimensions of the three-terminal multilayer ceramic capacitor 10. Furthermore, suppressing the protrusion in the contact region 60 makes it easier to form the first and second protrusions 41a, 41b.

[0135] (8) Effects of Including the Central Portion in the Contact Region The third and fourth extraction electrode portions 28b1, 28b2 are in contact with the third and fourth base electrode layers 32c, 32d in the contact region 60, which includes the central portion 40. In the contact region 60, the glass components of the third and fourth base electrode layers 32c, 32d are concentrated in the third and fourth base electrode layers 32c, 32d in the out-of-interface region 60b, which is separated from the contact interface 60a in the width direction y, to form a dense glass layer. The presence of glass components tends to facilitate sintering during firing, so the contact region 60, which includes the central portion 40, is likely to have a more recessed shape than the first and second protrusions 41a, 41b in a cross-sectional view along the first and second main surfaces 12a, 12b. On the other hand, in the first and second non-contact regions 61 a, 61 b, the non-contact region glass ratio g2 is low, so the first and second protrusions 41 a, 41 b are less likely to be concave, and the thickness of the first and second protrusions 41 a, 41 b can be ensured. Thus, while the thickness of the third and fourth base electrode layers 32 c, 32 d is reduced in the contact region 60 including the central portion 40, the thickness can be ensured in the first and second non-contact regions 61 a, 61 b ​​to ensure moisture-resistant reliability. Therefore, it is possible to prevent the third and fourth extraction electrodes 28 b 1, 28 b 2 from being misaligned with the third and fourth base electrode layers 32 c, 32 d, and to form the third and fourth base electrode layers 32 c, 32 d in shapes that can improve moisture-resistant reliability.

[0136] 4. Experimental Example Next, a three-terminal multilayer ceramic capacitor was manufactured as an experimental sample by the above manufacturing method, and a humidity resistance reliability test was carried out.

[0137] A. Preparation of Samples Three-terminal multilayer ceramic capacitors according to Examples 1 to 12 were fabricated according to the method for manufacturing a multilayer ceramic capacitor described above.

[0138] Here, with regard to the dimensions of each part of the third and fourth base electrode layers, the thickness in the width direction y of the first convex part is d1, the thickness in the width direction y of the second convex part is d2, the thickness in the width direction y of the central part is c, the width in the length direction z of the third (fourth) base electrode layer is e, the distance from the first convex part to the end of the first base electrode is a1, the distance from the second convex part to the end of the second base electrode is a2, the distance from the end of the base electrode which is the shorter of distance a1 and distance a2 to the first (second) limit point is f, and the distance from the convex part which is the shorter of distance a1 and distance a2 to the first (second) limit point is i.

[0139] Table 1 shows d1 (μm), c / d1, d2 (μm), c / d2, |d1-d2| (μm), c (μm), and d1(d2)-c (μm), which is the larger of d1 and d2 minus c, for Examples 1 to 12.

[0140]

[0141] Table 2 shows e (μm), a1 (μm), a1 / e, a2 (μm), a2 / e, f (μm), f / e, and i (μm) for Examples 1 to 12.

[0142]

[0143] The configuration of the three-terminal multilayer ceramic capacitor, other than the dimensions of each part of the third and fourth base electrode layers shown in Tables 1 and 2, is as follows, and is common to Examples 1 to 12. ◎ Structure of three-terminal multilayer ceramic capacitor: 3 terminals (see Figure 1) ◎ Dimensions of three-terminal multilayer ceramic capacitor L x W x T (including design values): 1.23 mm x 0.93 mm x 0.48 mm ◎ Ceramic layer material: BaTiO3 ◎ Capacitance: 22 μF ◎ Rated voltage: 4 V

[0144] First internal electrode layer Material: Ni Shape: See Figures 4 and 6 Number of layers: 220 Thickness of first internal electrode layer: 0.42 μm

[0145] Second internal electrode layer Material: Ni Shape: See Figures 5 and 7 Number of layers: 220 Thickness of second internal electrode layer: 0.42 μm

[0146] ◎ Structure of external electrodes First external electrode and second external electrode Base electrode layer: Baked layer containing conductive metal (Cu) and glass component Thickness at center of end face: 16 μm Plating layer: Two-layer structure of Ni plating layer and Sn plating layer Thickness of Ni plating layer: 5 μm Thickness of Sn plating layer: 5 μm

[0147] Third external electrode and fourth external electrode Base electrode layer: Baked layer containing conductive metal (Cu) and glass component Plated layer: Two-layer structure of Ni plated layer and Sn plated layer Thickness of Ni plated layer: 4 μm Thickness of Sn plated layer: 5 μm

[0148] B. Sample Evaluation A moisture-resistance reliability test was conducted on Examples 1 to 12. (Moisture-resistance reliability test) A moisture-resistance reliability test was conducted on each of the samples of Examples 1 to 12 based on the PCBT test method. More specifically, each sample was first mounted on a mounting board using solder. Subsequently, the insulation resistance value IR of each sample was measured (insulation resistance value 1 hour after the start of the moisture-resistance reliability test). Next, the mounting board was placed in a high-temperature, high-humidity chamber, and a DC current of 4 V was applied between the first and second external electrodes of each sample and between the third and fourth external electrodes of each sample in an environment of 125°C and 95% RH for 72 hours (moisture-resistance reliability test time). Then, after the moisture-resistance reliability test, the insulation resistance value IR of each sample was measured (insulation resistance value after the moisture-resistance reliability test). For each sample, if the log IR after the humidity resistance reliability test was reduced by 0.5 or more compared to the log IR before the humidity resistance reliability test, it was judged to have IR degradation. Those without IR degradation were rated as good, and those with IR degradation were rated as bad, and x.

[0149] The results of the moisture resistance reliability test are shown in Table 1.

[0150] Furthermore, the glass ratio was measured for Examples 7 to 9. (Measurement of Glass Ratio) The glass ratio in the third and fourth base electrode layers can be measured by taking an electron microscope photograph of a section taken along the LW plane including the third and fourth base electrode layers and performing elemental analysis of that region using an EDX (fluorescent X-ray analyzer). In the elemental analysis, it is sufficient to focus on the elements contained only in glass among the components constituting the third and fourth base electrode layers and perform the measurement.

[0151] Table 3 shows the out-of-interface region glass ratio g1, the first non-contact region glass ratio g2a, the second non-contact region glass ratio g2b, the non-contact region glass ratio g2 (average of g2a and g2b), g1 / g2a, g1 / g2b, and g1 / g2.

[0152]

[0153] C. Experimental Results In Examples 1 to 12 shown in Tables 1 to 3, the moisture resistance reliability test was evaluated as ◯, and moisture resistance reliability was ensured. Referring to the minimum and maximum values ​​of f / e in Table 2, it was found that 0.01≦f / e≦0.09 is preferable. More preferably, 0.02≦f / e≦0.08 is preferable. Referring to the minimum and maximum values ​​of a1 / e and a2 / e in Table 2, it was found that 0.10≦a / e≦0.30 is preferable. More preferably, 0.17≦a / e≦0.25 is preferable. Referring to the minimum and maximum values ​​of c / d1 and c / d2 in Table 1, it was found that 0.65≦c / d≦0.97 is preferable. More preferably, 0.67≦c / d≦0.95 is preferable. Referring to the minimum and maximum values ​​of c in Table 1, it was found that 8.0 μm≦c≦18.0 μm is preferable. More preferably, 9.0 μm≦c≦17.7 μm. Referring to the minimum and maximum values ​​of d1 and d2 in Table 1, it was found that 10.0 μm≦d≦21.0 μm is preferable. More preferably, 10.9 μm≦d≦20.0 μm. Referring to the minimum and maximum values ​​of e in Table 2, it was found that 200 μm≦e≦600 μm is preferable. More preferably, 230 μm≦e≦390 μm.

[0154] It is clear from Table 3 that the outer-interface region glass ratio g1 > the non-contact region glass ratio g2 is preferable. More preferably, 1.4≦g1 / g2≦1.7.

[0155] As described above, although the embodiments of the present invention have been disclosed in the above description, the present invention is not limited thereto. In other words, the present invention allows various modifications to be made to the above-described embodiments in terms of the configuration, shape, material, quantity, position, arrangement, etc., without departing from the scope of the technical idea and purpose of the present invention, and such modifications are included in the present invention.

[0156] <Modifications> (1) In the above embodiment, the third and fourth base electrode layers 32c and 32d each have two first and second protrusions 41a and 41b, and have a first limit point 45a on the first end face 12e side that is the first limit point 45a that is 3 μm or more from the first base electrode end 35a, and a second limit point 45b on the second end face 12f side that is the first limit point 45a that is 3 μm or more from the second base electrode end 35b. The third and fourth extraction electrode portions 28b1 and 28b2 are arranged to fall between the first limit point 45a and the second limit point 45b.

[0157] Alternatively, the third and fourth extraction electrode portions 28b1, 28b2 may be arranged to be contained between the first outer limit point and the second outer limit point where the overall thickness of the third and fourth external electrodes 30c, 30d is 3 μm or more.

[0158] Specifically, the third and fourth external electrodes 30c, 30d each have an outer central portion, a first outer convex portion 42a, and a second outer convex portion 42b in a state including the third and fourth plating layers 34c, 34d in addition to the third and fourth base electrode layers 32c, 32d. The outer central portion, the first outer convex portion 42a, and the second outer convex portion 42b correspond to the central portion 40, the first convex portion 41a, and the second convex portion 41b of the third and fourth base electrode layers 32c, 32d in the above embodiment.

[0159] In other words, the outer central portion is the portion of the third and fourth external electrodes 30c, 30d located at point M, which is the center in the longitudinal direction z of the third and fourth external electrodes 30c, 30d, and has a thickness in the width direction y relative to the first and second side surfaces 12c, 12d of 3 μm or more.

[0160] The first outer convex portion 42a is a portion of the third and fourth external electrodes 30c, 30d whose widthwise thickness y relative to the first and second side surfaces 12c, 12d is greater than that of the outer central portion, and which is located at point Q1, which is closer to the first end face 12e than the outer central portion.

[0161] The second outer convex portion 42b is a portion of the third and fourth external electrodes 30c, 30d whose widthwise thickness y relative to the first and second side surfaces 12c, 12d is greater than that of the outer central portion, and which is located at point Q2, which is closer to the second end face 12f than the outer central portion.

[0162] The third and fourth external electrodes 30c and 30d each have a first outer limit point and a second outer limit point, which are limit points on the third and fourth plating layers 34c and 34d, respectively, and correspond to the first and second limit points 45a and 45b of the third and fourth base electrode layers 32c and 32d in the above embodiment.

[0163] The first outer limit is the portion of the third and fourth external electrodes 30c, 30d located at point P1 on the first end face 12e side. At point P1, the first outer limit is the point where the thickness in the width direction y relative to the first and second side faces 12c, 12d becomes 3 μm or more for the first time from the end of the first external electrode on the first end face 12e side. The end of the first external electrode is the end of the third and fourth external electrodes 30c, 30d on the first end face 12e side.

[0164] The second outer limit is the portion of the third and fourth external electrodes 30c, 30d located at point P2 on the second end face 12f side. At point P2, the second outer limit is the point where the thickness in the width direction y relative to the first and second side faces 12c, 12d becomes 3 μm or more for the first time from the end of the second external electrode on the second end face 12f side. The end of the second external electrode is the end of the third and fourth external electrodes 30c, 30d on the second end face 12f side.

[0165] The third and fourth extraction electrode portions 28b and 28b are located between the first and second outer limit points, i.e., the first and second extraction ends 29a and 29b of the third and fourth extraction electrode portions 28b and 28b are located between the first and second outer limit points.

[0166] The thickness, distance, glass ratio, etc. of each portion of the third and fourth base electrode layers 32c, 32d in the above embodiment correspond to the thickness, distance, glass ratio, etc. of each portion of the third and fourth external electrodes 30c, 30d. Specifically, in the third and fourth base electrode layers 32c, 32d, the distance f from the first and second base electrode ends 35a, 35b to the first and second limit points 45a, 45b, the width e in the length direction z of the third and fourth base electrode layers 32c, 32d, the distance a from the first and second base electrode ends 35a, 35b to the first and second convex portions 41a, 41b, the thickness d in the width direction y of the first and second convex portions 41a, 41b relative to the first and second side surfaces 12c, 12d, the thickness c in the width direction y of the central portion 40 relative to the first and second side surfaces 12c, 12d, the out-of-interface region glass ratio g1, the non- The contact region glass ratio g2, etc. correspond to the distance from the first and second external electrode ends to the first and second outer limit points of the third and fourth external electrodes 30c, 30d, the width in the longitudinal direction z of the third and fourth external electrodes 30c, 30d, the distance from the first and second external electrode ends to the first and second outer convex portions 42a, 42b, the thickness in the width direction y of the first and second outer convex portions 42a, 42b relative to the first and second side surfaces 12c, 12d, the thickness in the width direction y of the central portion 40 relative to the first and second side surfaces 12c, 12d, the out-of-interface region glass ratio, the non-contact region glass ratio, etc.

[0167] In addition, the outer central portion, the first and second outer convex portions, and the first and second outer limit points in this modified example correspond to the central portion, the first and second convex portions, and the first and second limit points in the claims.

[0168] (2) In the above embodiment, the third and fourth base electrode layers 32c, 32d have two convex portions. However, the third and fourth base electrode layers 32c, 32d may have three or more convex portions as long as a large thickness range from the first limit point to the second limit point, where the thickness is 3 μm or more, can be secured.

[0169] <1> A laminate formed by laminating a plurality of ceramic layers and a plurality of internal electrode layers, the laminate having a first main surface and a second main surface opposing each other in a height direction, a first end surface and a second end surface opposing each other in a length direction perpendicular to the height direction, and a first side surface and a second side surface opposing each other in a width direction perpendicular to the height direction and the length direction; and external electrodes, wherein the internal electrode layers have: a plurality of first internal electrode layers extended to the first end surface and the second end surface; and a plurality of second internal electrode layers extended to the first side surface and the second side surface, and the external electrodes have: a first external electrode arranged on the first end surface and connected to the first internal electrode layer, a second external electrode arranged on the second end surface and connected to the first internal electrode layer, a third external electrode arranged on the first side surface and connected to the second internal electrode layer, and a fourth external electrode arranged on the second side surface and connected to the second internal electrode layer, the first internal electrode layer has a first opposing electrode portion opposing the second internal electrode layer, a first extraction electrode portion extending from the first opposing electrode portion to the first end face, and a second extraction electrode portion extending from the first opposing electrode portion to the second end face; the second internal electrode layer has a second opposing electrode portion opposing the first opposing electrode portion, a third extraction electrode portion extending from the second opposing electrode portion to the first side face, and a fourth extraction electrode portion extending from the second opposing electrode portion to the second side face;each of the third external electrode and the fourth external electrode has, in a cross-sectional view along the first main surface and the second main surface, a central portion located in the center in the length direction and having a thickness in the width direction relative to each of the first side surface and the second side surface of 3 μm or more; a first convex portion having a thickness in the width direction relative to each of the first side surface and the second side surface that is larger than that of the central portion and located closer to the first end face than the central portion; and a second convex portion having a thickness in the width direction relative to each of the first side surface and the second side surface that is larger than that of the central portion and located closer to the second end face than the central portion; and the third external electrode and the fourth external electrode each have a first limit point on the first end face side where the thickness in the width direction relative to each of the first side surface and the second side surface becomes 3 μm or more from the end of the second external electrode on the second end face side. a first lead end portion on the first end face side and a second lead end portion on the second end face side of the third lead electrode portion and the fourth lead electrode portion, respectively, being located between the first limit point and the second limit point.

[0170] <2> The three-terminal multilayer ceramic capacitor according to <1>, wherein, in a cross-sectional view along the first main surface and the second main surface, when a distance from an end of the first external electrode to the first limit point and a distance from an end of the second external electrode to the second limit point are defined as f, and when a width in the length direction of each of the third external electrode and the fourth external electrode is defined as e, 0.01≦f / e≦0.09 is satisfied.

[0171] <3> The three-terminal multilayer ceramic capacitor according to <1> or <2>, wherein, in a cross-sectional view along the first main surface and the second main surface, a distance from an end of the first external electrode to the first protrusion and a distance from an end of the second external electrode to the second protrusion are defined as a, and e is a width in the length direction of each of the third external electrode and the fourth external electrode.

[0172] <4> The three-terminal multilayer ceramic capacitor according to any one of <1> to <3>, wherein, in a cross-sectional view along the first main surface and the second main surface, when the thickness of each of the first protrusions and the second protrusions in the width direction relative to the first side surface and the second side surface is d and the thickness of the central portion in the width direction relative to the first side surface and the second side surface is c, the relationship c / d satisfies 0.65≦c / d≦0.97.

[0173] <5> The three-terminal multilayer ceramic capacitor according to any one of <1> to <4>, wherein, in a cross-sectional view along the first main surface and the second main surface, when the thickness of the central portion in the width direction relative to each of the first side surface and the second side surface is c, 8.0 μm≦c≦18.0 μm.

[0174] <6> The three-terminal multilayer ceramic capacitor according to any one of <1> to <5>, wherein, in a cross-sectional view along the first main surface and the second main surface, when the thickness in the width direction of each of the first protrusions and the second protrusions relative to the first side surface and the second side surface is d, 10.0 μm≦d≦21.0 μm.

[0175] <7> The three-terminal multilayer ceramic capacitor according to any one of <1> to <6>, wherein each of the third external electrode and the fourth external electrode includes a base electrode layer and a plating layer covering the base electrode layer, and the base electrode layers of the third external electrode and the fourth external electrode each have the central portion, the first convex portion, and the second convex portion, and also have the first limit point and the second limit point.

[0176] <8> The three-terminal multilayer ceramic capacitor according to any one of <1> to <7>, wherein the external electrodes contain a metal component and a glass component, and in a cross-sectional view along the first main surface and the second main surface, the third external electrode and the fourth external electrode include: a contact region including a contact interface in contact with the third lead electrode portion and the fourth lead electrode portion, respectively; and a first non-contact region that is not in contact with the third lead electrode portion and the fourth lead electrode portion, respectively, and is closer to the first end face than the contact region; and a second non-contact region that is closer to the second end face than the contact region, and an out-of-interface region glass ratio that is the ratio of the glass component to the component constituting the third external electrode and the fourth external electrode in an out-of-interface region excluding the contact interface in the contact region is greater than a non-contact region glass ratio that is the ratio of the glass component to the component constituting the third external electrode and the fourth external electrode in the first non-contact region and the second non-contact region, respectively.

[0177] <9> The three-terminal multilayer ceramic capacitor according to <8>, wherein the glass ratio in the out-of-interface region is 1.4 times or more and 1.7 times or less the glass ratio in the non-contact region.

[0178] <10> The three-terminal multilayer ceramic capacitor according to <8> or <9>, wherein the contact region includes the central portion.

[0179] <11> An external electrode paste for forming the external electrodes, comprising a resin, a metal filler, and a solvent, wherein the solvent comprises one or more first solvents and one or more second solvents, the mass ratio of the first solvent and the mass ratio of the second solvent to the mass of the solvent are each 40 mass% or more, and the lowest boiling point T of the one or more second solvents under atmospheric pressure is 40 mass% or more. Hl is the highest boiling point T among the boiling points of one or more of the first solvents under atmospheric pressure. Lh the highest boiling point T of the one or more second solvents under atmospheric pressure, which is 10° C. or more higher than Hh But, T Hl +10°C or lower, the lowest boiling point T of the first solvent under atmospheric pressureLl But, T Lh The solvent may contain a sub-solvent in addition to the first solvent and the second solvent, and the boiling point of the sub-solvent under atmospheric pressure is (T Ll -10) ° C or less, (T Lh +10)℃ (T Hl -10) ° C or less, or (T Hh <10>. The three-terminal multilayer ceramic capacitor according to any one of <1> to <10>, wherein the temperature is higher than +10°C, or the metal filler is a Cu filler, and the resin contains an ethyl cellulose-based resin and an acrylic-based resin, at least a portion of which are copolymerized, and an interfacial tension generated between the resin and the solvent is 15 mN / m or more.

[0180] REFERENCE SIGNS LIST 10: Three-terminal multilayer ceramic capacitor 12: Laminate 12a, 12b: First and second main surfaces 12c, 12d: First and second side surfaces 12e, 12f: First and second end surfaces 14: Ceramic layers 16: Internal electrode layers 16a, 16b: First and second internal electrode layers 18: Internal layer portions 20a, 20b: First and second main surface side outer layer portions 22a, 22b: First and second side surface side outer layer portions 24a, 24b: First and second end surface side outer layer portions 26a, 26b: First and second opposing electrode portions 27: Counter electrode portion regions 28a1, 28a2: First and second lead-out electrode portions 28b1, 28b2 : third and fourth lead-out electrode portions 29 : lead-out end portions 29a, 29b : first and second lead-out end portions 30 : external electrodes 30a, 30b : first and second external electrodes 30c, 30d : third and fourth external electrodes 32 : base electrode layers 32a, 32b : first and second base electrode layers 32c, 32d : third and fourth base electrode layers 34 : plating layers 34a, 34b : first and second plating layers 34c, 34d : third and fourth plating layers 35 : base electrode ends 35a, 35b : first and second base electrode ends 40 : central portion 41 : convex portions 41a, 41b : first and second convex portions 42 : outer convex portions 42a, 42b: First and second outer convex portions 45: Limit point 45a, 45b: First and second limit points 50a: First end face side region 50b: Second end face side region 50c: Central region 60: Contact region 60a: Contact interface 60b: Outer interface region 61: Non-contact region 61a, 61b: First and second non-contact regions 62: Alloy layer 70: External electrode paste 71, 72: First and second paste layers 80: Top 81: Reference limit point 81a, 81b: First and second reference limit points90, 90a: First and second application mechanisms 91, 91a: First and second supply rollers 92, 92a: First and second recesses 93, 93a: First and second application rollers 94, 94a: First and second paste tanks 95, 95a: First and second carrier tapes x: Height direction y: Width direction z: Length direction

Claims

1. a laminate formed by laminating a plurality of ceramic layers and a plurality of internal electrode layers, the laminate having a first main surface and a second main surface opposing each other in a height direction, a first end surface and a second end surface opposing each other in a length direction perpendicular to the height direction, and a first side surface and a second side surface opposing each other in a width direction perpendicular to the height direction and the length direction; an external electrode; The internal electrode layer is a plurality of first internal electrode layers extending to the first end surface and the second end surface; a plurality of second internal electrode layers extending to the first side surface and the second side surface, The external electrode is a first external electrode disposed on the first end face and connected to the first internal electrode layer; a second external electrode disposed on the second end face and connected to the first internal electrode layer; a third external electrode disposed on the first side surface and connected to the second internal electrode layer; a fourth external electrode disposed on the second side surface and connected to the second internal electrode layer; the first internal electrode layer has a first opposing electrode portion opposing the second internal electrode layer, a first extraction electrode portion extending from the first opposing electrode portion to the first end face, and a second extraction electrode portion extending from the first opposing electrode portion to the second end face, the second internal electrode layer has a second opposing electrode portion opposing the first opposing electrode portion, a third extraction electrode portion extending from the second opposing electrode portion to the first side surface, and a fourth extraction electrode portion extending from the second opposing electrode portion to the second side surface, each of the third external electrode and the fourth external electrode has, in a cross-sectional view along the first main surface and the second main surface, a central portion located in the center in the length direction and having a thickness in the width direction relative to each of the first side surface and the second side surface of 3 μm or more; a first convex portion having a thickness in the width direction relative to each of the first side surface and the second side surface that is larger than that of the central portion and located closer to the first end face than the central portion; and a second convex portion having a thickness in the width direction relative to each of the first side surface and the second side surface that is larger than that of the central portion and located closer to the second end face than the central portion; and the third external electrode and the fourth external electrode each have a first limit point on the first end face side where the thickness in the width direction relative to each of the first side surface and the second side surface becomes 3 μm or more from the end of the second external electrode on the second end face side. a first lead end portion on the first end face side and a second lead end portion on the second end face side of the third lead electrode portion and the fourth lead electrode portion, respectively, being located between the first limit point and the second limit point.

2. In a cross-sectional view along the first main surface and the second main surface, when the distance from the end of the first external electrode to the first limit point and the distance from the end of the second external electrode to the second limit point are denoted by f, and the width of each of the third external electrode and the fourth external electrode in the longitudinal direction is denoted by e, 2. The three-terminal multilayer ceramic capacitor according to claim 1, wherein 0.01≦f / e≦0.

09.

3. In a cross-sectional view along the first main surface and the second main surface, when the distance from the end of the first external electrode to the first convex portion and the distance from the end of the second external electrode to the second convex portion are denoted by a and the width of each of the third external electrode and the fourth external electrode in the longitudinal direction is denoted by e, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein 0.10≦a / e≦0.

30.

4. In a cross-sectional view along the first main surface and the second main surface, when the thickness of each of the first convex portion and the second convex portion in the width direction relative to the first side surface and the second side surface is denoted by d, and the thickness of the central portion in the width direction relative to the first side surface and the second side surface is denoted by c, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein 0.65≦c / d≦0.

97.

5. In a cross-sectional view along the first main surface and the second main surface, when the thickness of the central portion in the width direction relative to each of the first side surface and the second side surface is denoted by c, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein c satisfies 8.0 μm≦c≦18.0 μm.

6. In a cross-sectional view along the first main surface and the second main surface, when the thickness of each of the first convex portion and the second convex portion in the width direction relative to the first side surface and the second side surface is d, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein d satisfies 10.0 μm≦d≦21.0 μm.

7. each of the third external electrode and the fourth external electrode includes a base electrode layer and a plating layer covering the base electrode layer; 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein each of the base electrode layers of the third external electrode and the fourth external electrode has the central portion, the first convex portion, and the second convex portion, and also has the first limit point and the second limit point.

8. the external electrodes include a metal component and a glass component; In a cross-sectional view along the first main surface and the second main surface, the third external electrode and the fourth external electrode include a contact region including a contact interface in contact with the third lead electrode portion and the fourth lead electrode portion, respectively, and a first non-contact region that is not in contact with the third lead electrode portion and the fourth lead electrode portion, respectively, and is closer to the first end face than the contact region, and a second non-contact region that is closer to the second end face than the contact region, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein an out-of-interface region glass ratio, which is the ratio of the glass component to the components constituting the third external electrode and the fourth external electrode in an out-of-interface region excluding the contact interface in the contact region, is greater than a non-contact region glass ratio, which is the ratio of the glass component to the components constituting the third external electrode and the fourth external electrode in the first non-contact region and the second non-contact region, respectively.

9. 9. The three-terminal multilayer ceramic capacitor according to claim 8, wherein the glass ratio of the out-of-interface region is 1.4 times or more and 1.7 times or less the glass ratio of the non-contact region.

10. 9. The three-terminal multilayer ceramic capacitor according to claim 8, wherein the contact region includes the central portion.

11. Resin and A metal filler, a solvent; and an external electrode paste for forming the external electrodes, the solvent comprises one or more first solvents and one or more second solvents; a ratio of the mass of the first solvent to the mass of the solvent and a ratio of the mass of the second solvent to the mass of the solvent are each 40 mass% or more; The lowest boiling point T among the boiling points of one or more of the second solvents under atmospheric pressure Hl is the highest boiling point T among the boiling points of one or more of the first solvents under atmospheric pressure. Lh more than 10°C higher than The highest boiling point T among the boiling points of one or more of the second solvents under atmospheric pressure Hh But, T Hl +10°C or less, The lowest boiling point T among the boiling points of one or more of the first solvents under atmospheric pressure Ll But, T Lh -10°C or higher, The solvent may contain a sub-solvent in addition to the first solvent and the second solvent, The boiling point of the auxiliary solvent under atmospheric pressure is (T Ll -10) ° C or less, (T Lh +10)℃ (T Hl -10) ° C or less, or (T Hh +10) ° C. or more, or, the metal filler is a Cu filler, 3. The three-terminal multilayer ceramic capacitor according to claim 1, wherein the resin contains an ethyl cellulose-based resin and an acrylic-based resin, at least a portion of which is copolymerized, and an interfacial tension generated between the resin and the solvent is 15 mN / m or more.