Electronic component

Abstract

Provided is an electronic component with which high reliability during application of voltage can be obtained. An electronic component 1 comprises a laminate 2 in which dielectric layers 11, each having a thickness of 0.8-4.1 μm, and inner electrode layers 12, each having a thickness of 0.5-1.2 μm, are alternately laminated, and each of the number of the dielectric layers 11 and the number of the inner electrode layers 12 is 200-650 inclusive. In the electronic component, solid-solution layers 20 in which a first metal component, which is the main component of the inner electrode layers 12, has a second metal component, which is different from and the first metal component, mixed therein to form a solid solution, and are provided at the interfaces between the inner electrode layers 12 and the dielectric layers 11. The solid-solution layers 20 include: center solid-solution layers 21 located at least 10 μm inward from widthwise ends and longitudinal ends, at facing portions 12a that are of the inner electrode layers 12 adjacent to each other and that face each other; and outer solid-solution layers 22 surrounding the center solid-solution layers 21. The proportion of the second metal component to the first metal component in the form of the solid solution is larger in the center solid-solution layers 21 than in the outer solid-solution layers 22.

Description

Technical Field

[0001] The present invention relates to electronic components.

Background Art

[0002] For example, an electronic component such as a multilayer ceramic capacitor includes a laminate in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated, and two external electrodes respectively disposed on two end faces provided on both sides in the length direction of the laminate (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0005] In order to solve the above problems, the present invention provides an electronic component including a laminate in which a dielectric layer having a thickness of 0.8 μm or more and 4.1 μm or less and an internal electrode layer having a thickness of 0.5 μm or more and 1.2 μm or less are alternately laminated with each other, and the number of sheets of each of the dielectric layer and the internal electrode layer is 200 or more and 650 or less. A solid solution layer in which a second metal component different from the first metal component is dissolved in the first metal component, which is the main component of the internal electrode layer, is provided at the interface between the internal electrode layer and the dielectric layer. The solid solution layer includes a central solid solution layer located 10 μm or more inward from the ends in the length direction and the width direction at the facing portion where the adjacent internal electrode layers face each other, and an outer solid solution layer surrounding the central solid solution layer. The central solid solution layer has a larger ratio of solid solution of the second metal component with respect to the first metal component than the outer solid solution layer. An electronic component is provided.

Advantages of the Invention

[0006] According to the present invention, it is possible to provide an electronic component having high reliability when a voltage is applied.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the 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 at 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 with each other.

[0010] In the following description, as terms representing the orientation of the multilayer ceramic capacitor 1, in the multilayer ceramic capacitor 1, the direction in which the pair of external electrodes 3 are provided is defined as the length direction L. The direction in which the dielectric layers 11 and the internal electrode layers 12 are laminated is defined as the lamination direction T. The direction intersecting both the length direction L and the lamination direction T is defined as the width direction W. In the embodiment, the width direction W is orthogonal to both the length direction L and the lamination direction T. Also, the lamination direction T is also referred to as the thickness direction.

[0011] The multilayer ceramic capacitor 1 has a withstand voltage of about 25V, for example. The multilayer ceramic capacitor 1 has a substantially rectangular parallelepiped shape, and the dimension in the length direction L is 0.6 mm or more and 3.2 mm or less, the dimension in the width direction W is 0.3 mm or more and 2.5 mm or less, and the dimension in the thickness direction (lamination direction T) is 0.3 mm or more and 2.5 mm or less. Further, the multilayer ceramic capacitor 1 preferably has a chip size from 1005 size to 2012 size, the dimension in the length direction L is 1.0 mm or more and 2.0 mm or less, and the dimensions in the width direction W and the thickness direction (lamination direction T) are 0.5 mm or more and 1.25 mm or less.

[0012] In the following description, among the six outer surfaces of the laminate 2, a pair of outer surfaces facing each other in the lamination direction T are defined as the first main surface Aa and the second main surface Ab, a pair of outer surfaces facing each other in the width direction W are defined as the first side surface Ba and the second side surface Bb, and a pair of outer surfaces facing each other in the length direction L are defined as the first end surface Ca and the second end surface Cb. When it is not necessary to particularly distinguish between the first main surface Aa and the second main surface Ab, they are collectively referred to as the main surface A. When it is not necessary to particularly distinguish between the first side surface Ba and the second side surface Bb, they are collectively referred to as the side surface B. When it is not necessary to particularly distinguish between the first end surface Ca and the second end surface Cb, they are collectively referred to as the end surface C for description.

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

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

[0015] (Dielectric layer 11) The dielectric layer 11 is, for example, a sintered ceramic green sheet obtained by forming a slurry, which is obtained by adding a binder, additives such as a plasticizer and a dispersant, and an organic solvent to a mixture obtained by adding and mixing ceramic powder which is BaTiO3, a glass component, and a sintering aid as necessary, into a sheet shape. The thickness of the dielectric layer 11 is, for example, 0.8 μm or more and 4.1 μm or less, preferably 0.8 μm or more and 2.0 μm or less. Also, the number of dielectric layers 11 is, for example, 200 or more and 650 or less.

[0016] (Internal electrode layer 12) The internal electrode layer 12 is a sintered product of a paste for internal electrode layer containing powder of a first metal component which is a main component, a binder, additives such as a plasticizer and a dispersant, an organic solvent, and the like. The first metal component which is the main component of the internal electrode layer 12 is Ni in the embodiment, and hereinafter, the first metal component will be described as 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 1.2 μm or less, preferably 0.5 μm or more and 0.85 μm or less. Also, the number of the internal electrode layers 12, including the first internal electrode layers 12A and the second internal electrode layers 12B, is, for example, 200 or more and 650 or less.

[0018] The first internal electrode layer 12A includes a first facing portion 12Aa facing the second internal electrode layer 12B and a first lead-out portion 12Ab drawn from the first facing portion 12Aa toward the first end face Ca side. The end of the first lead-out portion 12Ab is exposed on the first end face Ca and is electrically connected to the first external electrode 3A described later. The second internal electrode layer 12B includes a second facing portion 12Ba facing the first internal electrode layer 12A and a second lead-out portion 12Bb drawn from the second facing portion 12Ba toward the second end face Cb. The end of the second lead-out portion 12Bb is electrically connected to the second external electrode 3B described later. Then, charges are accumulated in the first facing portion 12Aa of the first internal electrode layer 12A and the second facing portion 12Ba of the second internal electrode layer 12B.

[0019] Hereinafter, when there is no need to particularly distinguish and explain the first facing portion 12Aa and the second facing portion 12Ba, they will be collectively described as the facing portion 12a, and when there is no need to particularly distinguish and explain the first lead-out portion 12Ab and the second lead-out portion 12Bb, they will be collectively described as the lead-out portion 12b.

[0020] (Solid solution layer 20) On both sides of the internal electrode layer 12 in the stacking direction T, at the interfaces with the dielectric layer 11 or the outer layer portion 13, a solid solution layer 20 in which a second metal component different from the first metal component is dissolved in Ni, which is the first metal component, is provided. The solid solution layer 20 includes a central solid solution layer 21 and an outer solid solution layer 22. The second metal component is preferably Sn, In, Ga, Zn, Bi, Pb, Fe, V, Y, or Cu. In the embodiment, the second metal component is Sn. Hereinafter, the second metal component will be described as Sn. The solid solution layer 20 is a layer in which Sn atoms randomly substitute for Ni atoms 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.

[0021] In the embodiment, the solid solution layer 20 is provided at the interfaces on both sides in the stacking direction T of the internal electrode layer 12. However, the present invention is not limited to this, and the solid solution layer 20 may be provided only at the interface on one side in the stacking direction T of the internal electrode layer 12. Further, in the embodiment, the solid solution layer 20 is provided for all the internal electrode layers 12. However, the present invention is not limited to this, and the solid solution layer 20 may be provided only for some of the internal electrode layers 12.

[0022] (Central solid solution layer 21) The central solid solution layer 21 is provided at the interface between the internal electrode layer 12 and the dielectric layer 11 or the outer layer portion 13 in the central region in the length direction L and the width direction W of the laminate 2. In the central solid solution layer 21, Sn is dissolved in Ni at a larger ratio than in the outer solid solution layer 22. Here, the interface not only indicates a boundary but also a region that may include a part of the internal electrode layer 12 and the dielectric layer 11 or the outer layer portion 13. The central solid solution layer 21 is a region inside from the distance D1 from the end in the length direction L of the opposing portion 12a and the end in the width direction W of the opposing portion 12a. The distance D1 is about 10 μm in the embodiment. In the central solid solution layer 21, Sn is dissolved in an amount of 0.008 or more and 0.025 or less, preferably about 0.02, that is, 2 mol% with respect to the total molar amount of Ni and Sn. The ratio of Sn to Ni is a value obtained by measuring 10 points at the interfaces in the central portion in the stacking direction T, the central portion in the width direction W, and the central portion in the length direction L by TEM analysis and averaging the values.

[0023] (Outer solid solution layer 22) The outer solid solution layer 22 is provided in a region surrounding the central solid solution layer 21 in the opposing portion 12a. That is, the outer solid solution layer 22 is a region up to a distance D1 from the end in the length direction L of the opposing portion 12a and the end in the width direction W of the opposing portion 12a. In the outer solid solution layer 22, Sn is dissolved in an amount of 0.001 or more and 0.005 or less, preferably about 0.005, that is, 0.5 mol% with respect to the molar amount of Ni and Sn combined.

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

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

[0026] (External electrode 3) The external electrode 3 is provided on both end faces C of the laminate 2. The external electrode 3 covers not only the end face C but also a part of the main face A and the side face B on the end face C side.

[0027] As described above, the end of the first lead-out portion 12Ab of the first internal electrode layer 12A is exposed on the first end face Ca and is electrically connected to the first external electrode 3A. Also, the end of the second lead-out portion 12Bb of the second internal electrode layer 12B is exposed on the second end face Cb and is electrically connected to the second external electrode 3B. Thereby, between the first external electrode 3A and the second external electrode 3B, a structure is formed in which a plurality of capacitor elements are electrically connected in parallel.

[0028] (Manufacturing process) FIG. 4 is a flowchart for explaining an example of a method for manufacturing the multilayer ceramic capacitor 1. Note that this manufacturing method is an example, and the present invention is not limited thereto. FIG. 5 is a diagram for explaining the steps up to the production of the multilayer sheet 103 in the method for manufacturing the multilayer ceramic capacitor 1. The steps up to the production of this multilayer sheet 103 are also an example, and the present invention is not limited thereto.

[0029] (Ceramic green sheet production step S1) First, a ceramic slurry containing ceramic powder, a binder, and a solvent is prepared. By printing this ceramic slurry in a sheet form on a carrier film using a die coater, a gravure coater, a microgravure coater, or the like, the inner layer ceramic green sheet 101 shown in FIG. 5(a) is produced.

[0030] (One-side solid solution layer paste printing step S2) The one-side solid solution layer paste printing step S2 includes a central solid solution layer paste printing step S21 and an outer solid solution layer paste printing step S22.

[0031] (Central solid solution layer paste printing step S21) First, as shown in FIG. 5(b), a central solid solution layer paste 21P is printed on the surface of the inner layer ceramic green sheet 101. The central solid solution layer paste 21P is printed in the central regions in the length direction L and the width direction W of each laminate 2 when the laminate 2 is manufactured. The central region is a region inside from the end faces C on both sides in the length direction L of the laminate 2 and the side faces B on both sides in the width direction W of the laminate 2 by a distance D1 of 10 μm in the embodiment. The central solid solution layer paste 21P has Sn solid-dissolved in an amount of 0.008 or more and 0.025 or less, preferably about 0.02, that is, 2 mol% with respect to the molar amount of Ni + Sn. Note that the ratio of Sn to Ni in the central solid solution layer paste is substantially the same before and after firing.

[0032] (Outer solid solution layer paste printing step S22) Subsequently, as shown in FIG. 5(c), the paste 22P for the outer solid solution layer is printed on the surface of the ceramic green sheet 101 for the inner layer portion. The paste 22P for the outer solid solution layer is printed on the outer peripheral region outside the position of the distance D1 from the end faces C on both sides in the length direction L of the laminate 2 and the side faces B on both sides in the width direction W of the laminate 2, surrounding the central region. The paste 22P for the outer solid solution layer contains Sn in a molar amount of 0.001 or more and 0.005 or less, preferably about 0.005, that is, 0.5 mol% with respect to the total molar amount of Ni and Sn. The ratio of Sn to Ni contained in the paste 22P for the outer solid solution layer is lower than the ratio of Sn to Ni contained in the paste 21P for the central solid solution layer.

[0033] (Paste printing process S3 for the internal electrode layer) Next, as shown in FIG. 5(d), the paste 102 for the internal electrode layer is printed on the internal electrode formation region P where the paste 20P for the solid solution layer containing the paste 21P for the central solid solution layer and the paste 22P for the outer solid solution layer is printed.

[0034] (Paste printing process S4 for the other side) The paste printing process S4 for the other side also includes a central solid solution layer paste printing process S41 and an outer solid solution layer paste printing process S42, similar to the one-side solid solution layer paste printing process S2.

[0035] (Central solid solution layer paste printing process S41) First, as shown in FIG. 5(e), the paste 21P for the central solid solution layer is printed on the central region of the surface of the paste 102 for the internal electrode layer.

[0036] (Outer solid solution layer paste printing process S42) Subsequently, as shown in FIG. 5(f), the paste 22P for the outer solid solution layer is printed on the outer peripheral region of the surface of the paste 102 for the internal electrode layer. Through the above processes, the laminated sheet 103 is produced.

[0037] (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 stacked such that the regions printed with the solid solution layer paste 20P and the internal electrode layer paste 102 are shifted by a half pitch between adjacent laminated sheets 103. Further, the outer layer ceramic green sheets 112 are stacked on both sides of the plurality of laminated sheets 103 stacked.

[0038] (Thermal Compression Bonding Step S6) Subsequently, the outer layer ceramic green sheet 112 and the plurality of stacked laminated sheets 103 are thermally compression bonded. Thereby, the mother block 110 is formed.

[0039] (Mother Block Cutting Step S7) Next, the mother block 110 is cut along the cutting line X shown in FIG. 6 corresponding to the dimensions of the laminate 2 and the cutting line intersecting the cutting line X. Thereby, a plurality of laminates 2 are manufactured.

[0040] (External Electrode Formation Step S8) Next, external electrodes 3 are formed at both ends of the laminate 2.

[0041] (Firing Step S9) Then, the laminate 2 with the external electrodes 3 formed thereon is heated in a nitrogen atmosphere at a set firing temperature for a predetermined time. Thereby, the multilayer ceramic capacitor 1 is manufactured. At this time, the inner layer ceramic green sheet 101 and the outer layer ceramic green sheet 112 are sintered into ceramics, and the dielectric layer 11 and the outer layer portion 13 are formed.

[0042] In the firing step S9, the internal electrode layer paste 102 becomes the internal electrode layer 12, but the central solid solution layer paste 21P printed on both sides in the stacking direction T of the internal electrode layer paste 102 is heated to become the central solid solution layer 21, and the outer solid solution layer paste 22P is heated to become the outer solid solution layer 22. In the central solid solution layer 21, Sn is dissolved in an amount of 0.008 or more and 0.025 or less, preferably about 0.02, that is, 2 mol% based on the molar amount of Ni and Sn added together. In the outer solid solution layer 22, Sn is dissolved in an amount of 0.001 or more and 0.005 or less, preferably about 0.005, that is, 0.5 mol% based on the molar amount of Ni and Sn added together.

[0043] As described above, according to this embodiment, by forming the solid solution layer 20 on both surfaces in the stacking direction T of the internal electrode layer 12, the strength of the internal electrode layer 12 is improved, and the withstand voltage (breakdown voltage resistance) of the multilayer ceramic capacitor 1 is improved.

[0044] Furthermore, when Sn is dissolved in Ni, the state (electrical barrier height) near the interface between the internal electrode layer 12 and the dielectric layer 11 changes, and the high-temperature load life can be improved. As described above, a multilayer ceramic capacitor 1 excellent in reliability when a voltage is applied can be obtained.

[0045] Also, in the central solid solution layer 21 of the solid solution layer 20, Sn is dissolved in an amount of 0.008 or more and 0.025 or less, preferably about 0.02, that is, 2 mol% based on the molar amount of Ni and Sn added together. In the outer solid solution layer 22, Sn is dissolved in an amount of 0.001 or more and 0.005 or less, preferably about 0.005, that is, 0.5 mol% based on the molar amount of Ni and Sn added together. That is, in the solid solution layer 20, the central solid solution layer 21, which is the middle region, has a higher Sn content than the outer solid solution layer 22. Therefore, the central region of the internal electrode layer 12 can be particularly strengthened.

Explanation of Reference Numerals

[0046] A Main surface B Side surface C End face D1 Distance P Internal electrode formation region 1 Multilayer ceramic capacitor 1 Electronic component 2 Stacked body 3 External electrode 10 Inner layer part 11 Dielectric layer 12 Internal electrode layer 12a Opposing part 12b Lead-out part 13 Outer layer part 20 Solid solution layer 21 Central solid solution layer 22 Outer solid solution layer

Claims

1. An electronic component comprising a laminate in which a dielectric layer having a thickness of 0.8 μm or more and 4.1 μm or less and an internal electrode layer having a thickness of 0.5 μm or more and 1.2 μm or less are alternately laminated with each other, and the number of sheets of each of the dielectric layer and the internal electrode layer is 200 or more and 650 or less, a solid solution layer in which a second metal component different from the first metal component is solid-solved in the first metal component which is the main component of the internal electrode layer is provided at the interface between the internal electrode layer and the dielectric layer, the solid solution layer is, a central solid solution layer located 10 μm or more inward from the ends in the length direction and the width direction in the facing portion where the adjacent internal electrode layers face each other, and an outer solid solution layer surrounding the central solid solution layer, the central solid solution layer has a larger ratio of solid solution of the second metal component to the first metal component than the outer solid solution layer, electronic component.

2. In the central solid solution layer, the second metal component is solid-solved in an amount of 0.008 or more and 0.025 or less with respect to the molar amount obtained by adding the second metal component and the first metal component, in the outer solid solution layer, the second metal component is solid-solved in an amount of 0.001 or more and 0.005 or less with respect to the molar amount obtained by adding the second metal component and the first metal component, The electronic component according to Claim 1.

3. The first metal component is Ni, The electronic component according to Claim 1.

4. The first metal component is Ni, The electronic component according to Claim 2.

5. 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.

6. The thicknesses of the central solid solution layer and the outer solid solution layer are 1 nm or more and 20 nm or less, The electronic component according to any one of Claims 1 to 4.

7. The dimension in the length direction is 0.6 mm or more and 3.2 mm or less, the dimension in the width direction is 0.3 mm or more and 2.5 mm or less, the dimension in the thickness direction 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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