Multilayer capacitor

Abstract

To provide a multilayer capacitor having a configuration in which occurrence of cracks in an element body is suppressed, desired electrical characteristics are also secured, and connection reliability between an external electrode terminal and an internal electrode layer is improved.SOLUTION: In an element body of a multilayer capacitor C1, a plurality of dielectric layers and a plurality of internal electrode layers extend in a first direction and a second direction that are orthogonal to each other, and the plurality of dielectric layers and the plurality of internal electrode layers are alternately laminated in a third direction intersecting the first direction and the second direction. The element body includes at least one end surface. At least one internal electrode layer among the plurality of internal electrode layers is exposed from the plurality of dielectric layers on at least one end surface. The external electrode terminal is provided on the at least one end surface and is connected to the at least one internal electrode layer. In the element body, a weight ratio of a metal containing Ni is from 20% to 25%, and a weight ratio of sulfur is from 3 ppm to 20 ppm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multilayer capacitor. [Background technology]

[0002] There is known a multilayer capacitor having an element body and an external electrode terminal provided on the element body (for example, Patent Document 1). In the element body of this multilayer capacitor, a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated. The plurality of internal electrode layers are exposed from the plurality of dielectric layers at end faces of the element body. The external electrode terminal is connected to at least one of the internal electrode layers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-218060 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the multilayer capacitor described above, the connection between the external electrode terminals and the internal electrode layers allows the multilayer capacitor to function and ensures the electrical characteristics of the multilayer capacitor. For this reason, there is a demand for improving the connection reliability between the external electrode terminals and the internal electrode layers. It is believed that the connection reliability between the external electrode terminals and the internal electrode layers can be improved if the multiple internal electrode layers are configured to protrude from the multiple dielectric layers at the end faces.

[0005] In addition, the above-mentioned multilayer capacitor is also required to suppress the occurrence of cracks in the element body. If cracks occur, moisture may penetrate into the inside of the element body, and internal electrodes may be disconnected or shorted. For this reason, for example, chip components in which cracks have occurred in the element body during manufacturing are rejected. If the occurrence of cracks can be suppressed during manufacturing, production throughput will improve.

[0006] An object of one aspect of the present invention is to provide a multilayer capacitor having a configuration in which the occurrence of cracks in the element body is suppressed, desired electrical characteristics are ensured, and connection reliability between external electrode terminals and internal electrode layers is improved. [Means for solving the problem]

[0007] A multilayer capacitor according to one aspect of the present invention includes an element body and an external electrode terminal. In the element body, a plurality of dielectric layers and a plurality of internal electrode layers extend in first and second directions perpendicular to each other, and the plurality of dielectric layers and the plurality of internal electrode layers are alternately laminated in a third direction intersecting the first and second directions. The element body includes at least one end face. In the at least one end face, at least one internal electrode of the plurality of internal electrode layers is exposed from the plurality of dielectric layers. The external electrode terminal is disposed on the at least one end face. The external electrode terminal is connected to the at least one internal electrode layer. In the element body, the weight ratio of the metal containing Ni is 20% to 25%, and the weight ratio of sulfur is 3 ppm to 20 ppm.

[0008] As a result of intensive research, the inventors of the present application have found that the occurrence of cracks in the element body, the connection reliability between the external electrode terminals and the internal electrode layers, and the desired electrical characteristics depend on the content ratio of the metal and sulfur in the element body. According to the research results of the inventors of the present application, if the element body contains too little sulfur, the multiple internal electrode layers may not protrude from the multiple dielectric layers at the end faces. If the element body contains too much sulfur, cracks may occur in the element body. If the metal is too much, cracks may also occur in the element body. If the metal is too little, it is difficult to ensure the electrostatic capacitance per volume. In contrast, according to further research by the inventors of the present application, if the content ratio of the metal and sulfur in the element body is within the above range, the occurrence of cracks in the element body is suppressed, the desired electrical characteristics are ensured, and the connection reliability between the external electrode terminals and the internal electrode layers is improved. Therefore, the manufacturing throughput can be improved.

[0009] In the above-mentioned one aspect, when the end face is viewed from a direction perpendicular to the end face, the ratio of the area occupied by the multiple internal electrode layers to the area of ​​the end face may be 5% to 12%. In this case, the sulfur content of the internal electrode layers is easily balanced. Therefore, the manufacturing throughput can be improved.

[0010] In the above-mentioned one aspect, in each of the plurality of internal electrode layers, when the end face is viewed in a plan view from a direction perpendicular to the end face, a value obtained by dividing the area of ​​the internal electrode layer exposed from the plurality of dielectric layers by the volume of the internal electrode layer may be 0.15 to 0.40. In this case, the sulfur content in the element body is easily balanced. Therefore, the manufacturing throughput can be improved.

[0011] In the above-mentioned one aspect, at least one end face may include a pair of end faces. In the pair of end faces, different internal electrode layers among the plurality of internal electrode layers are exposed. The plurality of internal electrode layers may include a pair of internal electrode layers. The pair of internal electrode layers are adjacent to each other. The pair of internal electrode layers are exposed in different end faces among the pair of end faces. Each of the pair of internal electrodes may include an overlapping portion that overlaps with each other and a drawn portion that is connected to the overlapping portion and is exposed in the end face. When the width of the drawn portion in the second direction is "W1" and the width of the overlapping portion in the second direction is "W2", 1-(W1 / W2) may be 0.35 to 0.55. In this case, the sulfur content in the element body is easily reduced, and the thickness of the external electrode terminal is easily ensured. Therefore, the manufacturing throughput can be improved and the infiltration of liquid into the internal electrode layer can be suppressed.

[0012] In the above-mentioned one embodiment, the plurality of dielectric layers may form a pair of outer layer portions located outside the plurality of internal electrode layers in the third direction and sandwiching the plurality of internal electrode layers. The thickness of one of the pair of outer layer portions may be 5% to 10% of the total thickness of the element body in the third direction. In this case, the sulfur content in the element body is likely to be reduced, and the thickness of the external electrode terminal is likely to be ensured. Therefore, the manufacturing throughput can be improved and the infiltration of liquid into the internal electrode layers can be suppressed. Effect of the Invention

[0013] One aspect of the present invention provides a multilayer capacitor having a configuration in which the occurrence of cracks in the element body is suppressed, desired electrical characteristics are ensured, and the connection reliability between the external electrode terminals and the internal electrode layers is improved. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view of a multilayer capacitor according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a partial cross-sectional view of the multilayer capacitor. [Diagram 3] FIG. 2 is an end view of an element body in the multilayer capacitor. [Figure 4] 4 is a cross-sectional view of the element body as seen from the pull-out direction of the pull-out portion. FIG. [Diagram 5] FIG. 4 is a cross-sectional view of the element body as viewed from the stacking direction. [Figure 6] 1 is a graph for explaining the set temperatures in baking. [Figure 7] FIG. 4 is an enlarged view of the element body in the drawer portion. [Figure 8] 1 is a graph showing the relationship between the sulfur content and the protrusion length. [Figure 9] FIG. 13 is a diagram for explaining measurement of a protrusion amount. [Figure 10] 1 is a graph showing the relationship between the sulfur content, the capacitance, and the element thermal cracking. [Figure 11] FIG. 1 is a diagram showing various examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0016] First, the configuration of the multilayer capacitor in this embodiment will be described with reference to Figures 1 to 7. The multilayer capacitor C1 is, for example, a multilayer ceramic capacitor. Figure 1 is a perspective view of the multilayer capacitor in this embodiment. Figure 2 is a partial cross-sectional view of the multilayer capacitor.

[0017] As shown in Fig. 1 and Fig. 2, the multilayer capacitor C1 includes a rectangular parallelepiped element body 3 and a plurality of external electrode terminals 5. In this embodiment, the multilayer capacitor C1 includes a pair of external electrode terminals 5. The pair of external electrode terminals 5 are disposed on the outer surface of the element body 3. The pair of external electrode terminals 5 are spaced apart from each other. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and ridges, and a rectangular parallelepiped shape with rounded corners and ridges.

[0018] The element body 3 has a pair of side surfaces 3a facing each other, a pair of side surfaces 3c facing each other, and a pair of end surfaces 3e facing each other. The pair of side surfaces 3a, the pair of side surfaces 3c, and the pair of end surfaces 3e have a rectangular shape. The direction in which the pair of side surfaces 3a face each other is a third direction D3. The direction in which the pair of side surfaces 3c face each other is a second direction D2. The direction in which the pair of end surfaces 3e face each other is a first direction D1. The first direction D1 and the second direction D2 are perpendicular to each other. The third direction D3 intersects with the first direction D1 and the second direction D2.

[0019] The multilayer capacitor C1 is solder-mounted on an electronic device. The electronic device includes, for example, a circuit board or a multilayer capacitor. In the multilayer capacitor C1, one side surface 3a faces the electronic device. The one side surface 3a is arranged so as to form a mounting surface. The one side surface 3a is the mounting surface. Of the pair of side surfaces 3c, one side surface 3c may be arranged so as to form a mounting surface. For example, when the side surface 3a forms a first side surface, the side surface 3c forms a second side surface.

[0020] The third direction D3 is a direction perpendicular to each side surface 3a and perpendicular to the second direction D2. The first direction D1 is a direction parallel to each side surface 3a and each side surface 3c and perpendicular to the second direction D2 and the third direction D3. The second direction D2 is a direction perpendicular to each side surface 3c, and the first direction D1 is a direction perpendicular to each end surface 3e. In this embodiment, the length of the element body 3 in the first direction D1 is greater than the length of the element body 3 in the second direction D2 and is greater than the length of the element body 3 in the third direction D3. The first direction D1 is the longitudinal direction of the element body 3. The length of the element body 3 in the second direction D2 and the length of the element body 3 in the third direction D3 may be equal to each other. The length of the element body 3 in the first direction D1 and the length of the element body 3 in the third direction D3 may be different from each other. In the example shown in this embodiment, the first direction D1 corresponds to the Y-axis direction, the second direction D2 corresponds to the X-axis direction, and the third direction D3 corresponds to the Z-axis direction.

[0021] The length of element body 3 in the third direction D3 is the height of element body 3. The length of element body 3 in the second direction D2 is the width of element body 3. The length of element body 3 in the first direction D1 is the length of element body 3. In this embodiment, the height T of element body 3 is 0.27 to 2.90 mm, the width W of element body 3 is 0.27 to 2.90 mm, and the length L of element body 3 is 0.57 to 3.60 mm. For example, the height T of element body 3 is 1.84 mm, the width W of element body 3 is 1.83 mm, and the length L of element body 3 is 3.35 mm.

[0022] The pair of side surfaces 3c extend in the third direction D3 to connect the pair of side surfaces 3a. The pair of side surfaces 3c also extend in the first direction D1. The pair of end surfaces 3e extend in the third direction D3 to connect the pair of side surfaces 3a. The pair of end surfaces 3e also extend in the second direction D2.

[0023] The element body 3 has four ridges 3g, four ridges 3i, and four ridges 3j. The ridges 3g are located between the end face 3e and the side face 3a. The ridges 3i are located between the end face 3e and the side face 3c. The ridges 3j are located between the side face 3a and the side face 3c. In this embodiment, the ridges 3g, 3i, and 3j are rounded so as to be curved. The element body 3 is subjected to a so-called R chamfering process. The end face 3e and the side face 3a are indirectly adjacent to each other via the ridges 3g. The end face 3e and the side face 3c are indirectly adjacent to each other via the ridges 3i. The side face 3a and the side face 3c are indirectly adjacent to each other via the ridges 3j.

[0024] The element body 3 has a plurality of dielectric layers 12, a plurality of internal electrode layers 13, and a plurality of internal electrode layers 15. In the element body 3, the plurality of dielectric layers 12, the plurality of internal electrode layers 13, and the plurality of internal electrode layers 15 are alternately stacked in a third direction D3. In other words, the stacking direction of the plurality of dielectric layers 12 and the stacking direction of the plurality of internal electrode layers 13, 15 coincide with the third direction D3. The plurality of dielectric layers 12, the plurality of internal electrode layers 13, and the plurality of internal electrode layers 15 extend in the first direction D1 and the second direction D2.

[0025] Each dielectric layer 12 contains an oxide ceramic. Each dielectric layer 12 is formed, for example, from a sintered body of a ceramic green sheet containing a dielectric material. The dielectric material includes, for example, a BaTiO3-based, Ba(Ti,Zr)O3-based, or (Ba,Ca)TiO3-based dielectric ceramic. In the actual element body 3, the dielectric layers are integrated to such an extent that the boundaries between the dielectric layers are not visible.

[0026] Each of the internal electrode layers 13, 15 is an internal conductor disposed within the element body 3. The multiple internal electrode layers 13, 15 face each other in the third direction D3. The multiple internal electrode layers 13 are located closer to one of the pair of end faces 3e than the multiple internal electrode layers 15. The multiple internal electrode layers 15 are located closer to the other of the pair of end faces 3e than the multiple internal electrode layers 13.

[0027] At least one end of the multiple internal electrode layers 13 is exposed from the corresponding end face 3e. At least one end of the multiple internal electrode layers 15 is exposed from the corresponding end face 3e. The multiple internal electrode layers 13, 15 have one end exposed from the corresponding end face 3e. The multiple internal electrode layers 13, 15 are connected to the corresponding external electrode terminals 5 at the portions exposed from the end face 3e. Figures 2 and 3 show, as an example, a state in which the multiple internal electrode layers 15 are exposed from the end face 3e. Figure 3 is an end view of the element body 3 of the multilayer capacitor C1.

[0028] When the end face 3e is viewed from a first direction D1 perpendicular to the end face 3e, the proportion of the area of ​​the end face 3e occupied by the multiple internal electrode layers 15 is 5% to 12%. Similarly, when the end face 3e is viewed from a first direction D1 perpendicular to the end face 3e, the proportion of the area of ​​the end face 3e occupied by the multiple internal electrode layers 13 is 5% to 12%.

[0029] The multiple internal electrode layers 13, 15 include a pair of internal electrode layers 13, 15 adjacent to each other and exposed at different end faces 3e of a pair of end faces 3e. As shown in Figures 3 to 5, each of the pair of internal electrode layers 13, 15 includes an extended portion 15b and an overlapping portion 15c. Figure 4 is a cross-sectional view of the element body 3 along the stacking direction as seen from the first direction D1. Figure 5 is a cross-sectional view of the element body 3 along the first direction D1 and the second direction D2 as seen from the stacking direction.

[0030] The overlapping portion 15c is a portion of the pair of internal electrode layers 13, 15 that overlaps with each other. The drawn-out portion 15b is a portion of each internal electrode layer 13, 15 that is connected to the overlapping portion 15c. The drawn-out portion 15b extends from the overlapping portion 15c in the first direction D1 and is exposed at the end surface 3e. When the width of the drawn-out portion 15b in the second direction D2 is "W1" and the width of the overlapping portion 15c in the second direction D2 is "W2", 1-(W1 / W2) is 0.35 to 0.55. 1-(W1 / W2) can be expressed as a percentage as the drawing rate. When the above condition is satisfied, the drawing rate is 35% to 55%.

[0031] In each of the multiple internal electrode layers 15, when the end face 3e is viewed in plan from a direction perpendicular to the end face 3e, the area of ​​the internal electrode layer 15 exposed from the multiple dielectric layers 12 divided by the volume of the internal electrode layer 15 is 0.15 to 0.4. Similarly, in each of the multiple internal electrode layers 13, when the end face 3e is viewed in plan from a direction perpendicular to the end face 3e, the area of ​​the internal electrode layer 13 exposed from the multiple dielectric layers 12 divided by the volume of the internal electrode layer 13 is 0.15 to 0.4.

[0032] The area of ​​the internal electrode layers 13, 15 exposed from the plurality of dielectric layers 12 is calculated, for example, by the product of the width W1 of the drawn-out portion 15b in the second direction D2 and the thickness of the drawn-out portion 15b in the third direction D3. The volume of the internal electrode layers 13, 15 is the sum of the volume of the drawn-out portion 15b and the volume of the overlapping portion 15c. The volume of the drawn-out portion 15b is calculated, for example, by the product of the width W1 of the drawn-out portion 15b in the second direction D2, the width of the drawn-out portion 15b in the first direction, and the thickness of the drawn-out portion 15b. The volume of the overlapping portion 15c is calculated, for example, by the product of the width W2 of the overlapping portion 15c in the second direction D2, the width of the overlapping portion 15c in the first direction D1, and the thickness of the overlapping portion 15c.

[0033] Each of the internal electrode layers 13, 15 is made of a conductive material that is usually used as an internal conductor of a multilayer electronic component. The conductive material includes, for example, a base metal. The conductive material includes, for example, Ni or Cu. The internal electrode layers 13, 15 are configured as a sintered body of a conductive paste that includes the above-mentioned conductive material. In this embodiment, the internal electrode layers 13, 15 are made of Ni. In the element body 3, the weight ratio of the metal containing Ni is 20% to 25%. In the element body 3, the weight ratio of sulfur is 3 ppm to 20 ppm.

[0034] For example, the sulfur content in the element body 3 varies depending on the temperature setting of the binder removal process carried out before the firing process of the element body 3. In the binder removal process, the organic binders and organic solvents contained in the dielectric layer 12 and the internal electrode layers 13 and 15 before firing are removed from the element body 3. In the binder removal process, the element body 3 placed on a setter is placed in a furnace and heated in the furnace for 1 to 20 hours while maintaining a constant binder removal temperature. The setter includes, for example, a vent hole that penetrates from the front side to the back side on which the element body 3 before firing is placed. In the binder removal process, the organic binders and organic solvents in the element body 3 are gasified by vaporizing or decomposing them. FIG. 6 shows an example of a temperature setting and time profile in the binder removal process. In this case, the binder removal process includes a range Rs in which the temperature setting is maintained at 1000 degrees.

[0035] The internal electrode layers 13 and the internal electrode layers 15 are arranged at different positions (layers) in the third direction D3. The internal electrode layers 13 and the internal electrode layers 15 are arranged alternately in the element body 3 so as to face each other with a gap in the third direction D3. The internal electrode layers 13 and the internal electrode layers 15 have polarities different from each other. One end of the internal electrode layers 13, 15 is exposed at the corresponding end face 3e. The internal electrode layers 13, 15 have one end exposed at the corresponding end face 3e.

[0036] The multiple internal electrode layers 13 and the multiple internal electrode layers 15 are alternately arranged in the third direction D3. Each internal electrode layer 13, 15 is located in a plane substantially parallel to the side surface 3a. Each internal electrode layer 13, 15 extends in the first direction D1 and the second direction D2. The internal electrode layers 13 and the internal electrode layers 15 face each other in the third direction D3. The third direction D3 in which the internal electrode layers 13 and the internal electrode layers 15 face each other is perpendicular to the first direction D1 and the second direction D2 parallel to the side surface 3a. The direction parallel to the side surface 3a corresponds to the first direction D1 and the second direction D2.

[0037] As shown in Figures 3 and 4, the multiple internal electrode layers 13 include one outermost internal electrode layer 13A located outermost in the third direction D3. The outermost internal electrode layer 13A faces one of the pair of side surfaces 3a in the third direction D3. The multiple internal electrode layers 15 include one outermost internal electrode layer 15A located outermost in the third direction D3. The outermost internal electrode layer 15A faces the other of the pair of side surfaces 3a in the third direction D3.

[0038] The dielectric layers 12 form a pair of outer layer portions 12A, 12B that are located outside the internal electrode layers 13, 15 in the third direction D3 and sandwich the internal electrode layers 13, 15. The pair of outer layer portions 12A, 12B are located outside the outermost internal electrode layers 13A, 15A in the third direction D3. The pair of outer layer portions 12A, 12B are located so as to sandwich the internal electrode layers 13, 15 including the outermost internal electrode layers 13A, 15A. The pair of outer layer portions 12A, 12B are located outside all the internal electrode layers 13, 15 in the third direction D3. The pair of outer layer portions 12A, 12B are located so as to sandwich all the internal electrode layers 13, 15 in the third direction D3. The thickness of one of the pair of outer layer portions 12A, 12B is 5% to 10% of the total thickness of the element body 3 in the third direction D3.

[0039] Fig. 7 is an enlarged view of the element body at the lead-out portion 15b. As shown in Fig. 7, the internal electrode layers 15 protrude from the dielectric layers 12. Similarly, the internal electrode layers 13 protrude from the dielectric layers 12. The lead-out portions 13b, 15b of the internal electrode layers 13, 15 protrude from the dielectric layers 12 at each end face 3e. The lead-out portions 13b, 15b of the internal electrode layers 13, 15 protrude from the pair of outer layer portions 12A, 12B in the first direction D1 at each end face 3e.

[0040] A protruding length P1 of the multiple internal electrode layers 13, 15 protruding from the pair of outer layer portions 12A, 12B correlates with the sulfur content in the element body 3. The protruding length P1 is the maximum length of the internal electrode layers 13, 15 protruding from the pair of outer layer portions 12A, 12B in the first direction D1. The protruding length P1 depends on the residual amount of sulfur in the element body 3. The greater the residual amount of sulfur in the element body 3, the greater the protruding length P1.

[0041] FIG. 8 is a graph showing the relationship between the sulfur content and the protruding length. In FIG. 8, data DA1 shows a plot of the measured values ​​of the protruding length P1 against the sulfur content. Data DA2 is an approximation line of all the data DA1. In measuring the protruding length P1, as shown in FIG. 9, a profile in a first direction D1 is obtained for the end face 3e of the sintered element body 3 by scanning in the direction of the arrow α. For example, a laser microscope is used to obtain the profile. For example, the maximum length by which the internal electrode layer 15 protrudes from the pair of outer layer portions 12A, 12B is measured by scanning in the direction of the arrow α, and the maximum length is recorded as the protruding length P1. The direction of the arrow α is, for example, the third direction D3.

[0042] The multilayer capacitor C1 includes a pair of external electrode terminals 5. The pair of external electrode terminals 5 are arranged on the outer surface of the element body 3. The pair of external electrode terminals 5 are spaced apart from each other. The external electrode terminals 5 may be indirectly arranged on the dielectric layer 12 via an electrical insulating film. The external electrode terminals 5 are arranged on the corresponding end face 3e side of the element body 3. In this embodiment, the external electrode terminals 5 are arranged on a pair of side faces 3a, a pair of side faces 3c, and one end face 3e.

[0043] The external electrode terminal 5 is formed so as to cover five faces, namely, the pair of side faces 3a, one end face 3e, and the pair of side faces 3c, as well as the ridges 3g, 3i, and 3j. The external electrode terminal 5 is electrically connected to the corresponding internal electrode layers 13 and 15. The external electrode terminal 5 includes, for example, a plurality of electrode layers. For example, the external electrode terminal 5 includes a first electrode layer and a second electrode layer covering the first electrode layer.

[0044] 2, the length B of the external electrode terminals 5 in the first direction D1 is 0.10 to 0.90 mm. The gap G between the pair of external electrode terminals 5 in the first direction D1 is 0.20 to 3.20 mm. For example, the length B of the external electrode terminals 5 in the first direction D1 is 0.70 mm. The gap G between the pair of external electrode terminals 5 in the first direction D1 is 1.95 mm.

[0045] In this embodiment, the first electrode layer includes a sintered metal layer. The sintered metal layer is formed by baking a conductive paste applied to the surface of the element body 3. The sintered metal layer is formed by sintering a metal component (metal powder) included in the conductive paste. In this embodiment, the sintered metal layer is made of Cu. The sintered metal layer may be made of Ni. The sintered metal layer includes a base metal. The conductive paste includes, for example, a powder made of Cu or Ni, a glass component, an organic binder, and an organic solvent.

[0046] The second electrode layer is formed on the first electrode layer by a plating method. In this embodiment, the second electrode layer includes a first plating layer and a second plating layer. In this embodiment, the first plating layer is formed on the conductive resin layer of the first electrode layer by Ni plating. The first plating layer is a Ni plating layer. The first plating layer may be a Sn plating layer, a Cu plating layer, or an Au plating layer. The first plating layer includes Ni, Sn, Cu, or Au. The first plating layer covers the baked metal layer.

[0047] The second plating layer is formed on the first plating layer by a plating method. The second plating layer is a solder plating layer. In the example shown in this embodiment, the second plating layer is formed on the first plating layer by Sn plating. The second plating layer is a Sn plating layer. The second plating layer may be a Sn-Ag alloy plating layer, a Sn-Bi alloy plating layer, or a Sn-Cu alloy plating layer. The second plating layer contains Sn, a Sn-Ag alloy, a Sn-Bi alloy, or a Sn-Cu alloy.

[0048] Next, the effects of the multilayer capacitor C1 described above will be described. In the element body 3 of the multilayer capacitor C1, the weight ratio of the metal containing Ni is 20% to 25%, and the weight ratio of sulfur is 3 ppm to 20 ppm. In this case, the occurrence of cracks in the element body 3 is suppressed, the desired electrical characteristics are ensured, and the connection reliability between the external electrode terminals 5 and the internal electrode layers 13, 15 is improved. Therefore, the manufacturing throughput can be improved.

[0049] Fig. 10 is a graph showing the relationship between the sulfur content, capacitance, and element thermal cracks. In Fig. 10, data DA3 shows a plot of capacitance CV value versus sulfur content. Data DA4 shows a plot of the incidence rate of element thermal cracks versus sulfur content. Data DA5 is an approximation line of data DA3. Data DA6 is an approximation line of data DA3.

[0050] Data DA3 is a CV value calculated from the capacitance measured 30 times for each of a number of lots with different sulfur contents. Data DA4 is a result of a thermal test. In the thermal test, the fired element 3 is immersed in a solder bath at 400°C for three seconds, and then removed and judged whether cracks have occurred. Data D4 is the crack occurrence rate after immersion in the solder bath and judgment of crack occurrence are repeated 60 times.

[0051] When the end face 3e is viewed from a direction perpendicular to the end face 3e, the ratio of the area of ​​the end face 3e occupied by the multiple internal electrode layers 13, 15 may be 5% to 12%. That is, the ratio of the exposed area of ​​the drawn-out portions 13b, 15b to the area of ​​the end face 3e may be 5% to 12%. In this case, the sulfur content of the internal electrode layers 13, 15 is easily balanced. Therefore, the manufacturing throughput can be improved. For example, it is considered that the larger the area of ​​the internal electrode layers 13, 15 exposed from the end face 3e, the easier it is for sulfur to be removed from the element body 3 in the binder removal process.

[0052] In each of the multiple internal electrode layers 13, 15, when the end face 3e is viewed in a plan view from a direction perpendicular to the end face 3e, the value obtained by dividing the area of ​​the internal electrode layer 13, 15 exposed from the multiple dielectric layers 12 by the volume of the internal electrode layer 13, 15 may be 0.15 to 0.40. That is, the ratio of the exposed area of ​​the drawn-out portion 13b, 15b to the volume of the internal electrode layer 13, 15 may be 0.15 to 0.40. In this case, the sulfur content in the element body 3 is easily balanced. Therefore, the manufacturing throughput can be improved. For example, it is considered that the larger the area of ​​the internal electrode layer 13, 15 exposed from the end face 3e is relative to the volume of the internal electrode layer 13, 15 containing sulfur, the more sulfur is removed from the element body 3 in the binder removal process, and the less likely sulfur is to remain in the element body 3.

[0053] When the width of the drawn-out portion 15b in the second direction D2 is "W1" and the width of the overlapping portion 15c in the second direction D2 is "W2", 1-(W1 / W2) may be 0.35 to 0.55. That is, the drawing rate may be 35% to 55%. In this case, the sulfur content in the element body 3 is likely to be reduced, and the thickness of the external electrode terminal 5 is likely to be ensured. Therefore, the manufacturing throughput can be improved and the infiltration of liquid into the internal electrode layers 13 and 15 can be suppressed. For example, when the external electrode terminal 5 is formed by dipping into a solder bath, if the width W1 of the drawn-out portion 15b in the second direction D2 is too large, it is difficult to ensure the thickness of the external electrode terminal 5.

[0054] When viewed from the first direction D1, if the distance WG1 from the overlapping portions 13c, 15c in the second direction D2 to the edge of the external electrode terminal 5 is too small, the risk of the internal electrode layers 13, 15 being exposed from the side surface 3c can be reduced. If the width W1 of the drawn-out portions 13b, 15b in the second direction D2 is too large, when viewed from the first direction D1, the distance WG2 from the drawn-out portions 13b, 15b to the edge of the external electrode terminal 5 in the second direction D2 becomes small, making it difficult to ensure the thickness of the external electrode terminal 5.

[0055] The thickness of one of the pair of outer layer portions 12A, 12B may be 5% to 10% of the overall thickness of the element body in the third direction D3. In this case, the sulfur content in the element body 3 is likely to be reduced, and the thickness of the external electrode terminal 5 is likely to be ensured. This can improve manufacturing throughput and suppress infiltration of liquid into the internal electrode layers 13, 15. For example, when the external electrode terminal 5 is formed by dipping in a solder bath, the smaller the thickness of one of the pair of outer layer portions 12A, the more the sulfur content is reduced, but it is more difficult to ensure the thickness of the external electrode terminal 5.

[0056] Next, Examples 1 to 12 and Comparative Examples 1 to 5 will be described with reference to Fig. 11. In the multilayer capacitors of Examples 1 to 12, the weight ratio of the metal containing Ni was 20% to 25%, and the weight ratio of sulfur was 3 ppm to 20 ppm. In these cases, it was confirmed that the thermal crack occurrence rate in the element body 3 was 0%, the capacitance CV value was 1.22% to 1.49%, and the protrusion length P1 was 3.6 µm or more.

[0057] In the multilayer capacitors of Examples 1 to 7 and Examples 9 to 12, the ratio of the exposed area of ​​the drawn-out portions 13b, 15b to the area of ​​the end face 3e was 5% to 12%. In these cases, it was confirmed that the metal content was 20.4% to 24.8%, and the sulfur content was 3.7 ppm to 17.2 ppm.

[0058] In the multilayer capacitors of Examples 1 to 8 and Examples 10 to 12, the ratio of the exposed area of ​​the lead-out portions 13b, 15b to the volume of the internal electrode layers 13, 15 was 0.15 to 0.40. In these cases, it was confirmed that the metal content was 20.4% to 24.8%, and the sulfur content was 3.7 ppm to 17.2 ppm.

[0059] In the multilayer capacitors of Examples 1 to 9 and Example 12, the drawing ratio was 35% to 55%. In these cases, it was confirmed that the metal content was 20.4% to 24.8%, and the sulfur content was 3.7 ppm to 17.2 ppm.

[0060] In the multilayer capacitors of Examples 1 to 10, the thickness of each of the outer layer portions 12A, 12B is 5% to 10% of the total thickness of the element body in the third direction D3. In this case, it was confirmed that the metal content was 20.4% to 24.8%, and the sulfur content was 3.7 ppm to 17.2 ppm. Furthermore, it was confirmed that the multilayer capacitors of Examples 1 to 7 also prevented the infiltration of plating liquid.

[0061] Although the embodiments and modifications of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0062] For example, the configuration of the element body 3 of the multilayer capacitor C1 may be other than those shown in Examples 1 to 12. The configuration in which the weight ratio of the metal containing Ni is 20% to 25% and the weight ratio of sulfur is 3 ppm to 20 ppm may be controlled by a process other than the binder removal process.

[0063] As will be understood from the description of the above embodiments, the present specification includes disclosure of the following aspects. (Appendix 1) an element body in which a plurality of dielectric layers and a plurality of internal electrode layers extending in first and second directions perpendicular to each other are alternately stacked in a third direction intersecting the first and second directions, and at least one of the plurality of internal electrode layers includes at least one end face exposed from the plurality of dielectric layers; an external electrode terminal disposed on the at least one end surface and connected to the at least one internal electrode layer, The multilayer capacitor, wherein in the element, the weight ratio of the metal containing Ni is 20% to 25%, and the weight ratio of sulfur is 3 ppm to 20 ppm. (Appendix 2) 2. The multilayer capacitor according to claim 1, wherein, when the end face is viewed from a direction perpendicular to the end face, a proportion of an area of ​​the end face occupied by the plurality of internal electrode layers is 5% to 12%. (Appendix 3) 3. The multilayer capacitor according to claim 1, wherein in each of the plurality of internal electrode layers, when the end face is viewed in a plan view from a direction perpendicular to the end face, a value obtained by dividing an area of ​​the internal electrode layer exposed from the plurality of dielectric layers by a volume of the internal electrode layer is 0.15 to 0.40. (Appendix 4) the at least one end surface includes a pair of end surfaces at which different internal electrode layers of the plurality of internal electrodes are exposed, the plurality of internal electrode layers include a first pair of internal electrode layers adjacent to each other and exposed at different end faces of the pair of end faces, each of the pair of internal electrode layers includes an overlapping portion overlapping with each other, and a lead portion connected to the overlapping portion, extending from the overlapping portion in the first direction, and exposed at the end surface; The multilayer capacitor according to any one of Appendix 1 to Appendix 3, wherein, when the width of the drawn-out portion in the second direction is "W1" and the width of the overlapped portion in the second direction is "W2", 1-(W1 / W2) is 0.35 to 0.55. (Appendix 5) the plurality of dielectric layers form a pair of outer layer portions located outside the plurality of internal electrode layers in the third direction and positioned so as to sandwich the plurality of internal electrode layers, 5. The multilayer capacitor according to claim 1, wherein a thickness of one of the pair of outer layer portions is 5% to 10% of an overall thickness of the element body in the third direction. [Explanation of symbols]

[0064] 3...element body, 3e...end surface, 5...external electrode terminal, 12...dielectric layer, 12A, 12B...outer layer portion, 13, 15...internal electrode layer, 13b, 15b...drawing portion, 15c...overlapping portion, C1...multilayer capacitor, D1...first direction, D2...second direction, D3...third direction, Rs...range, W1, W2...width.

Claims

1. an element body in which a plurality of dielectric layers and a plurality of internal electrode layers extending in first and second directions perpendicular to each other are alternately stacked in a third direction intersecting the first and second directions, and at least one of the plurality of internal electrode layers includes at least one end face exposed from the plurality of dielectric layers; an external electrode terminal disposed on the at least one end surface and connected to the at least one internal electrode layer, In the element body, the weight ratio of the metal containing Ni is 20% to 25%, and the weight ratio of sulfur is 3 ppm to 20 ppm.

2. 2. The multilayer capacitor according to claim 1, wherein, when the end face is viewed in a plan view from a direction perpendicular to the end face, a ratio of an area of ​​the end face occupied by the plurality of internal electrode layers to an area of ​​the end face is 5% to 12%.

3. 3. The multilayer capacitor according to claim 1, wherein, in each of the plurality of internal electrode layers, when the end face is viewed in a plan view from a direction perpendicular to the end face, a value obtained by dividing an area of ​​the internal electrode layer exposed from the plurality of dielectric layers by a volume of the internal electrode layer is 0.15 to 0.

40.

4. the at least one end surface includes a pair of end surfaces at which different internal electrode layers of the plurality of internal electrodes are exposed, the plurality of internal electrode layers include a first pair of internal electrode layers adjacent to each other and exposed at different end faces of the pair of end faces, each of the pair of internal electrode layers includes an overlapping portion overlapping with each other, and a lead portion connected to the overlapping portion, extending from the overlapping portion in the first direction, and exposed at the end surface; The width of the pull-out portion in the second direction is "W １ " and the width of the overlapping portion in the second direction is "W ２ ", then 1-(W １ / W ２ 3. The multilayer capacitor according to claim 1, wherein the ratio of the ratio ...

5. the plurality of dielectric layers form a pair of outer layer portions located outside the plurality of internal electrode layers in the third direction and positioned so as to sandwich the plurality of internal electrode layers, 3. The multilayer capacitor according to claim 1, wherein a thickness of one of said pair of outer layer portions is 5% to 10% of an overall thickness of said element body in said third direction.

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