Electronic Components

Abstract

Provided is an electronic component from which high reliability can be obtained when a voltage is applied thereto. In an internal electrode layer 12 of an electronic component 1, a first internal electrode layer 12A and a second internal electrode layer 12B are alternately disposed. The first internal electrode layer 12A includes an opposite portion 12a opposite an adjacent, another internal electrode layer 12, and a lead-out portion 12b for connection from the opposite portion 12a to an outer electrode 3 disposed on one end surface. The second internal electrode layer 12B includes an opposite portion 12a and a lead-out portion 12b for connection from the opposite portion 12a to an outer electrode 3 disposed on another end surface. The lead-out portion 12b includes a curving portion 121 that curves toward the center in a stacking direction moving from the opposite portion 12a toward the end surface. A solid-solution layer 20 is provided at an interface between the curving portion 121 and the dielectric layer 11. In the solid-solution layer 20, a second metal component different from a first metal component that is a principal component of the internal electrode layer 12 is solid-dissolved. In the solid-solution layer 20, the second metal component is solid-dissolved at a molar ratio of more than or equal to 0.001 with respect to a molar amount of the sum of the first metal component and the second metal component.

Description

[Technical field]

[0001] The present invention relates to electronic components. [Background technology]

[0002] For example, an electronic component such as a multilayer ceramic capacitor includes a laminate in which multiple dielectric layers and multiple internal electrode layers are alternately stacked, and two external electrodes arranged on two end faces of the laminate on both sides in the longitudinal direction (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-09222 A Summary of the Invention [Problem to be solved by the invention]

[0004] Such electronic components are required to have high reliability when a voltage is applied thereto. An object of the present invention is to provide an electronic component that can obtain high reliability when a voltage is applied thereto. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a laminate in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated with each other, and two external electrodes arranged on two end faces provided on both sides in a longitudinal direction of the laminate, the internal electrode layer comprising a first internal electrode layer having an opposing portion facing another internal electrode layer adjacent in the lamination direction, and a lead portion extending from the opposing portion to one of the end faces and connecting to the external electrode arranged on the one of the end faces, and a lead portion extending from the opposing portion to the other of the end faces and connecting to the external electrode arranged on the other of the end faces. and second internal electrode layers having lead portions connected to electrodes are arranged alternately with each other, the lead portions having curved portions that curve toward the center of the stacking direction as they move from the opposing portion side toward the end face, and a solid-solution layer is provided at the interface between the curved portion and the dielectric layer in which a first metal component that is a main component of the internal electrode layers is dissolved with a second metal component different from the first metal component, and in the solid-solution layer the second metal component is dissolved at a molar ratio of 0.001 or more and 0.1 or less with respect to the sum of the molar amount of the first metal component and the second metal component. Effect of the Invention

[0006] According to the present invention, it is possible to provide an electronic component that has high reliability when a voltage is applied. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic perspective view of a multilayer ceramic capacitor 1 according to an embodiment. [Diagram 2] 2 is a cross-sectional view taken along line II-II of the multilayer ceramic capacitor 1 in FIG. [Diagram 3] 3 is a cross-sectional view taken along line III-III of the multilayer ceramic capacitor 1 in FIG. [Figure 4] 3 is a flowchart illustrating an example of a method for manufacturing the multilayer ceramic capacitor 1. [Diagram 5] 1A to 1C are diagrams illustrating steps up to the production of a laminated sheet 103 in a manufacturing method of the laminated ceramic capacitor 1. [Figure 6] 2A to 2C are diagrams illustrating a lamination step in the method for manufacturing the multilayer ceramic capacitor 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a multilayer ceramic capacitor 1 according to an embodiment of the present invention will be described. Fig. 1 is a schematic perspective view of the multilayer ceramic capacitor 1 of the embodiment. Fig. 2 is a cross-sectional view taken along line II-II of the multilayer ceramic capacitor 1 in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III of the multilayer ceramic capacitor 1 in Fig. 1.

[0009] The multilayer ceramic capacitor 1 includes a laminate 2 and a pair of external electrodes 3 provided on both ends of the laminate 2. The laminate 2 includes an inner layer portion 10 in which dielectric layers 11 and internal electrode layers 12 are alternately laminated.

[0010] In the following description, the terminology used to indicate the orientation of the multilayer ceramic capacitor 1 is the length direction L, which is the direction in which the pair of external electrodes 3 are provided in the multilayer ceramic capacitor 1. The direction in which the dielectric layers 11 and the internal electrode layers 12 are stacked is the stacking direction T. The direction intersecting both the length direction L and the stacking direction T is the width direction W. In the embodiment, the width direction W is perpendicular to both the length direction L and the stacking direction T. The stacking direction T is also referred to as the thickness direction.

[0011] The multilayer ceramic capacitor 1 has, for example, a withstand voltage of about 25 V. It has a substantially rectangular parallelepiped shape with a length direction L dimension of 0.6 mm to 3.2 mm, a width direction W dimension of 0.3 mm to 2.5 mm, and a thickness direction (stacking direction T) dimension of 0.3 mm to 2.5 mm, and preferably is a multilayer ceramic capacitor 1 of size 1005 to size 2012 with a length direction L dimension of 1.0 mm to 2.0 mm, and a width direction W dimension and a thickness direction (stacking direction T) dimension of 0.5 mm to 1.25 mm.

[0012] In the following description, among the six outer surfaces of the laminate 2, a pair of outer surfaces facing in the stacking direction T will be referred to as the first main surface Aa and the second main surface Ab, a pair of outer surfaces facing in the width direction W will be referred to as the first side surface Ba and the second side surface Bb, and a pair of outer surfaces facing in the length direction L will be referred to as the first end surface Ca and the second end surface Cb. Note that when it is not necessary to distinguish between the first main surface Aa and the second main surface Ab and to describe them separately, they will be collectively referred to as the main surface A, when it is not necessary to distinguish between the first side surface Ba and the second side surface Bb and when it is not necessary to distinguish between the first end surface Ca and the second end surface Cb and to describe them separately, they will be collectively referred to as the end surface C.

[0013] (Laminate 2) The laminate 2 comprises an inner layer portion 10, outer layer portions 13 arranged on both sides of the inner layer portion 10 in the stacking direction T, and side gap portions 30 provided on both sides of the inner layer portion 10 and the outer layer portion 13 in the width direction W.

[0014] (Inner layer 10) In the inner layer portion 10, dielectric layers 11 and internal electrode layers 12 are laminated alternately one by one.

[0015] (Dielectric layer 11) The dielectric layer 11 is formed by sintering a ceramic green sheet obtained by forming a slurry into a sheet shape from a mixture of ceramic powder, for example BaTiO3, a glass component, and optionally a sintering aid, which is then mixed with a binder, additives such as a plasticizer and a dispersant, and an organic solvent. The thickness of the dielectric layer 11 is, for example, 0.8 μm or more and 4.1 μm or less. The number of the dielectric layers 11 is 200 or more and 650 or less.

[0016] (Internal electrode layer 12) The internal electrode layer 12 is formed by sintering an internal electrode layer paste containing a powder of a first metal component as a main component, a binder, additives such as a plasticizer and a dispersant, an organic solvent, etc. The first metal component as a main component of the internal electrode layer 12 is Ni in the embodiment, and the following description will be given assuming that the first metal component is Ni.

[0017] The internal electrode layer 12 includes a plurality of first internal electrode layers 12A and a plurality of second internal electrode layers 12B. The first internal electrode layers 12A and the second internal electrode layers 12B are alternately arranged. The thickness of the internal electrode layer 12 is, for example, 0.5 μm or more and 1.1 μm or less. The number of the internal electrode layers 12, including the first internal electrode layers 12A and the second internal electrode layers 12B, is 200 or more and 650 or less.

[0018] The first internal electrode layer 12A includes a first opposing portion 12Aa opposing the second internal electrode layer 12B, and a first lead portion 12Ab led from the first opposing portion 12Aa toward the first end face Ca. An end of the first lead portion 12Ab is exposed at the first end face Ca and is electrically connected to a first external electrode 3A described below. The second internal electrode layer 12B includes a second opposing portion 12Ba opposing the first internal electrode layer 12A, and a second lead portion 12Bb led from the second opposing portion 12Ba to a second end face Cb. An end of the second lead portion 12Bb is electrically connected to a second external electrode 3B described later. Then, electric charges are stored in the first opposing portion 12Aa of the first internal electrode layer 12A and the second opposing portion 12Ba of the second internal electrode layer 12B.

[0019] In the following, unless it is necessary to distinguish between the first opposing portion 12Aa and the second opposing portion 12Ba, they will be collectively referred to as opposing portion 12a, and unless it is necessary to distinguish between the first drawn-out portion 12Ab and the second drawn-out portion 12Bb, they will be collectively referred to as drawn-out portion 12b.

[0020] (curved portion 121) A curved portion 121 is provided in the lead-out portion 12b of the internal electrode layer 12. FIG. 2 is a cross section passing through a center portion in a width direction W intersecting with the stacking direction T and the length direction L, and extending in the stacking direction T and the length direction L. As shown in FIG. 2, the curved portion 121 is provided in an end region on the end face C side, away from a position of a distance D1 from the end face C. The curved portion 121 curves toward the center portion in the stacking direction T from the opposing portion 12a side toward the end face C. Note that the curved portion may have two or more inflection points, or may have only one inflection point, and the size of the inflection does not matter.

[0021] The degree of curvature of the curved portion 121 is smallest in the internal electrode layer 12 at the center in the stacking direction T, and in the embodiment, the curved portion 121 of the internal electrode layer 12 at the center in the stacking direction T is approximately straight. The degree of curvature of the curved portion 121 increases toward the main surface A side. That is, the degree of curvature of the curved portion 121 of the internal electrode layer 12 closest to the main surface A is greatest. In other words, the degree of curvature of the curved portion 121 furthest from the center in the stacking direction T is greatest. In the internal electrode layer 12 located closest to the main surface A, the distance D2 in the stacking direction T between the position in the stacking direction T of the end portion on the end face C side of the curved portion 121 and the position in the stacking direction T of the opposing portion 12a is 3 μm or more and 100 μm or less.

[0022] (solid solution layer 20) On both sides of the curved portion 121 in the stacking direction T, at the interface with the dielectric layer 11 or the outer layer portion 13, there is provided a solid solution layer 20 in which a first metal component, which is Ni, the main component of the internal electrode layer 12, is dissolved in a second metal component different from the first metal component at a molar ratio of 0.001 or more and 0.1 or less with respect to the sum of the molar amount of the first metal component and the second metal component. The second metal component is preferably Sn, In, Ga, Zn, Bi, Pb, Fe, V, Y or Cu, and in the embodiment, the second metal component is Sn, and hereinafter, the second metal component will be described as Sn. The solid solution layer 20 is a layer in which Sn atoms randomly replace Ni within the atomic arrangement structure of Ni while maintaining the atomic arrangement structure of Ni. The thickness of the solid solution layer 20 is preferably 1 nm or more and 20 nm or less. The solid solution layer 20 can be measured by measuring 10 points in a region including the interface between the dielectric layer 11 and the internal electrode 12 by TEM analysis. The number of moles is the average value of the 10 points.

[0023] The solid solution layer 20 is provided in the curved portion 121 of the internal electrode layer 12. In the embodiment, the solid solution layer 20 further extends to the entire lead portion 12Ab and the lead portion 12Bb including the curved portion 121, and to a region within at least 10 μm from the lead portion 12Ab and the lead portion 12Bb side of the facing portion 12Aa and the facing portion 12Ba. The solid solution layer 20 may be provided only in the curved portion 121 of the internal electrode layer 12. In addition, a solid solution layer 20 is provided at the interface with the dielectric layer 11 or the outer layer portion 13 on both sides of the curved portion 121 in the stacking direction T, but this is not limited to the above, and the solid solution layer 20 may be provided on only one surface of the internal electrode layer 12 in the stacking direction T. Furthermore, in the embodiment, the solid solution layer 20 is provided at the interface with the dielectric layer 11 or the outer layer portion 13 on both sides of the stacking direction T of all of the internal electrode layers 12, but this is not limited thereto, and the solid solution layer 20 may be provided only in some of the internal electrode layers 12.

[0024] (Outer layer part 13) The outer layer portions 13 are provided on both sides of the inner layer portion 10 in the stacking direction T, and are made of the same dielectric ceramic material as the dielectric layers 11.

[0025] (Side gap section 30) The side gap portions 30 are provided on both sides of the inner layer portion 10 and the outer layer portion 13 in the width direction W, and are made of the same dielectric ceramic material as the dielectric layers 11.

[0026] (External electrode 3) The external electrodes 3 are provided on both end faces C of the laminate 2. The external electrodes 3 cover not only the end faces C but also parts of the main face A and the side faces B on the end face C side.

[0027] As described above, the end of the first lead portion 12Ab of the first internal electrode layer 12A is exposed to the first end face Ca and is electrically connected to the first external electrode 3A. Moreover, the end of the second lead portion 12Bb of the second internal electrode layer 12B is exposed to the second end face Cb and is electrically connected to the second external electrode 3B. This results in a structure in which multiple capacitor elements are electrically connected in parallel between the first external electrode 3A and the second external electrode 3B.

[0028] (manufacturing process) Fig. 4 is a flow chart for explaining an example of a method for manufacturing the multilayer ceramic capacitor 1. Note that this manufacturing method is merely an example, and the present invention is not limited thereto. Fig. 5 is a diagram for explaining steps up to the production of a laminated sheet 103, which will be described later, in the manufacturing method for the multilayer ceramic capacitor 1. The steps up to the production of the laminated sheet 103 are also merely an example, and the present invention is not limited thereto.

[0029] (Ceramic green sheet production process S1) First, a ceramic slurry containing ceramic powder, a binder, and a solvent is prepared. The ceramic slurry is printed in a sheet form on a carrier film using a die coater, a gravure coater, a microgravure coater, or the like, to produce an inner layer ceramic green sheet 101 shown in FIG. 5(a).

[0030] (Paste printing process S2 for solid solution layer on one side) As shown in FIG. 5(b), a paste 20P for a solid solution layer is printed on the surface of the ceramic green sheet 101 for an inner layer portion in an area where the curved portion 121 is to be formed.

[0031] (Internal electrode layer paste printing process S3) Next, as shown in FIG. 5(c), the internal electrode layer paste 102, which becomes the internal electrode layer 12, is printed in the internal electrode formation region P including the region where the curved portion 121 on which the solid solution layer paste 20P is printed is to be formed.

[0032] (Other side solid solution layer paste printing process S4) Furthermore, the solid solution layer paste 20P is printed on the surface of the internal electrode layer paste 102 at the same position as the position where the internal electrode layer paste 102 was printed in the one-surface-side solid solution layer paste printing step S2. Through the above steps, the laminated sheet 103 is produced.

[0033] (Lamination process S5) Next, in the lamination step S5, a plurality of laminated sheets 103 are laminated. Fig. 6 is a diagram for explaining the lamination step. As shown in the figure, a plurality of laminated sheets 103 are laminated so that the internal electrode forming regions P, on which the solid solution layer paste 20P and the internal electrode layer paste 102 are printed, are shifted by half a pitch between adjacent laminated sheets 103. Furthermore, outer layer ceramic green sheets 112 are laminated on both sides of the laminated laminated sheets 103.

[0034] (Thermocompression bonding process S6) Next, the outer layer ceramic green sheets 112 and the stacked laminate sheets 103 are thermocompression bonded to each other, thereby forming the mother block 110.

[0035] (Mother block cutting process S7) Next, the mother block 110 is cut along cutting lines X and cutting lines intersecting with the cutting lines X shown in Fig. 6, which correspond to the dimensions of the laminate 2. In this way, a plurality of laminates 2 are manufactured.

[0036] (Formation of curved portion 121) In this laminate 2, an end region at a certain distance in the longitudinal direction L from the portion cut along the cutting line X to become the end face C of the laminate 2 is an area in which the pull-out portion 12b is formed, and in the laminate sheet 103, portions on which the internal electrode layer paste 102 is printed and portions on which it is not printed are alternately laminated. On the other hand, in the inner region at a certain distance or more from the end face C, the facing portion 12a is formed, and only the portion of the laminate sheet 103 where the internal electrode layer paste 102 is printed is laminated. That is, the region where the drawn-out portion 12b is arranged has half the number of sheets of the internal electrode layer paste 102 compared to the region where the facing portion 12a is arranged, so the thickness in the stacking direction T becomes thinner compared to the inner region toward the end face C. Therefore, the drawn-out portion 12b forms a curved portion 121 that curves more toward the end face C.

[0037] (External electrode formation step S8) Next, an external electrode 3 is formed on the thinner portion of the laminate 2 on the end face C side.

[0038] (Firing process S9) Then, the laminate 2 on which the external electrodes 3 are formed is heated in a nitrogen atmosphere at a set firing temperature for a predetermined time. In this way, the multilayer ceramic capacitor 1 is manufactured. At this time, the ceramic green sheets 101 for the internal layer portions and the ceramic green sheets 112 for the external layer portions are sintered to become ceramics, and the dielectric layers 11 and the external layer portions 13 are formed. In this firing step S9, the internal electrode layer paste 102 becomes the internal electrode layers 12, but the solid-solution layer paste 20P printed on both sides of the internal electrode layer paste 102 in the lamination direction T is heated to become the solid-solution layer 20.

[0039] As described above, this embodiment has the following advantages. The curved portion 121 is formed by deformation of the pull-out portion 12b caused by stacking and pressing a plurality of laminated sheets 103 during the lamination step S5 and the thermocompression bonding step S6. The strength of the portion of the pull-out portion 12b where the curved portion 121 is formed may be reduced due to this deformation. However, in the embodiment, the solid solution layer 20 is formed on both surfaces of the curved portion 121 in the stacking direction T, thereby improving the strength of the curved portion 121 and improving the pressure resistance (voltage resistance) of the multilayer ceramic capacitor 1.

[0040] Furthermore, the presence of Sn in Ni changes the state (electrical barrier height) in the vicinity of the interface with dielectric layer 11 at curved portion 121, improving the high temperature load life. As a result, a multilayer ceramic capacitor 1 with excellent reliability when voltage is applied can be obtained. [Explanation of symbols]

[0041] 1. Multilayer ceramic capacitors 2. Laminate 3 External electrode 10 Inner Layer 11 Dielectric layer 12 Internal electrode layer 12A 1st internal electrode layer 12Ab 1st drawer 12B 2nd internal electrode layer 12Bb 2nd drawer 12a Opposite part 12b Drawer part 13 Outer layer 20 Solid solution layer 20P Paste for solid solution layer 30 Side gap section 121 Curved section

Claims

1. a laminate in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately stacked; two external electrodes disposed on two end surfaces of the laminate provided on both sides in the longitudinal direction, The internal electrode layer is a first internal electrode layer having an opposing portion opposing another internal electrode layer adjacent in the lamination direction and a lead portion extending from the opposing portion to one of the end faces and connecting with the external electrode arranged on the one of the end faces, and a second internal electrode layer having the opposing portion and a lead portion extending from the opposing portion to the other of the end faces and connecting with the external electrode arranged on the other of the end faces, the first internal electrode layer and the second internal electrode layer having the opposing portion and a lead portion extending from the opposing portion to the other of the end faces and connecting with the external electrode arranged on the other of the end faces are alternately arranged with each other, the pull-out portion has a curved portion that curves toward a center in the stacking direction from the opposing portion toward the end surface, a solid solution layer is provided at an interface between the curved portion and the dielectric layer, in which a second metal component different from a first metal component that is a main component of the internal electrode layer is solid-solved in the first metal component, and the second metal component is solid-solved in the first metal component, an electronic component, wherein the second metal component is dissolved in the solid solution layer at a molar ratio of 0.001 or more and 0.1 or less with respect to a total molar amount of the first metal component and the second metal component.

2. the solid solution layer extends to a region within at least 10 μm from the drawn-out portion including the curved portion and the drawn-out portion side of the opposing portion; 2. The electronic component according to claim 1.

3. a distance between a position of the end of the curved portion on the end face side in the stacking direction and a position of the opposing portion in the stacking direction is 3 μm or more and 100 μm or less; The electronic component according to claim 1 .

4. a distance between a position of the end of the curved portion on the end face side in the stacking direction and a position of the opposing portion in the stacking direction is 3 μm or more and 100 μm or less; The electronic component according to claim 2 .

5. The thickness of the internal electrode layer is 0.5 μm or more and 1.1 μm or less. The electronic component according to any one of claims 1 to 4.

6. The first metal component is Ni; The electronic component according to any one of claims 1 to 4.

7. The second metal component is Sn, In, Ga, Zn, Bi, Pb, Fe, V, Y or Cu; The electronic component according to any one of claims 1 to 4.

8. The thickness of the solid solution layer is 1 nm or more and 20 nm or less. The electronic component according to any one of claims 1 to 4.

9. The length direction dimension is 0.6 mm or more and 3.2 mm or less, The width direction dimension is 0.3 mm or more and 2.5 mm or less, The thickness direction dimension is 0.3 mm or more and 2.5 mm or less. The electronic component according to any one of claims 1 to 4.

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