Electronic Components

Abstract

Provided is an electronic component with which high reliability can be obtained when a voltage is applied. This electronic component 1 is configured so that in an end region on an end-surface side of a position 5%–20% or 10 μm–50 μm distant in a length direction from an end surface of a lead section 12b of an inner electrode layer 12 of the electronic component: at an interface with a dielectric layer 11, a first solid solution layer 21 is provided in which a second metal constituent is put in solid solution in a first metal constituent that is a principal constituent of the inner electrode layer 12, the second metal constituent differing from the first metal constituent; and, in a central region, in the length direction and a width direction, of a facing section 12a, at an interface with the dielectric layer 11, a second solid solution layer 22 is provided in which the second metal constituent is put in solid solution in the first metal constituent at a higher concentration than in the first solid solution layer 21.

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 stacked, and two external electrodes are respectively arranged on two end faces provided on both sides in a longitudinal direction of the laminate, the internal electrode layers being a first internal electrode layer having an opposing portion facing another internal electrode layer adjacent in the stacking 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 internal electrode layers and the first metal layer are alternately arranged, and in an end region of the lead-out portion toward the end face from a position that is 5% to 20% or 10 μm to 50 μm in the longitudinal direction from the end face, a first solid-solution layer is provided at the interface with the dielectric layer, in which a first metal component that is a main component of the internal electrode layers is solid-solved with a second metal component different from the first metal component, and in a central region in the longitudinal and width directions of the opposing portion, a second solid-solution layer is provided at the interface with the dielectric layer, in which the second metal component is solid-solved with the first metal component at a higher concentration than in the first solid-solution layer. 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 16 V. It has a substantially rectangular parallelepiped shape with a length L dimension of 0.09 mm to 1.1 mm, a width W dimension of 0.004 mm to 0.6 mm, and a thickness direction (stacking direction T) dimension of 0.004 mm to 0.6 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, to which a binder, additives such as a plasticizer and a dispersant, and an organic solvent are added. The thickness of the dielectric layer 11 is, for example, 0.3 μm or more and 0.8 μm or less. The number of the dielectric layers 11 is 50 or more and 1000 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, 0.3 μm or more and 0.8 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 50 or more and 1000 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 from a position of a distance D1 from the end face C. The distance D1 is a position that is 5% to 20% of the lengthwise distance from the end face C, or 10 μm to 50 μm. The curved portion 121 is curved toward the center portion in the stacking direction T from the opposing portion 12a side toward the end face C.

[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 the largest. In other words, the degree of curvature of the curved portion 121 furthest from the center in the stacking direction T is the largest. 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 face C side end of the curved portion 121 and the position in the stacking direction T of the opposing portion 12a is 5 μm or more and 50 μm or less.

[0022] (solid solution layer 20) Furthermore, at the interface between the dielectric layer 11 or the outer layer 13 on both sides of the stacking direction T of the internal electrode layer 12, a solid solution layer 20 is provided in which a second metal component different from the first metal component is dissolved in Ni, which is a first metal component. The solid solution layer 20 includes a first solid solution layer 21 and a second solid solution layer 22. 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 the second metal component will be described below as Sn. The solid solution layer 20 is a layer in which Sn atoms randomly replace Ni in the atomic arrangement structure of Ni while maintaining the atomic arrangement structure of Ni. The thickness of the solid solution layer 20 is 1 nm to 40 nm, and preferably 1 nm to 20 nm.

[0023] In the embodiment, the solid solution layer 20 is provided at the interface on both sides of the internal electrode layer 12 in the stacking direction T, but the present invention is not limited thereto, and the solid solution layer 20 may be provided only at the interface on one side of the internal electrode layer 12 in the stacking direction T. In addition, in the embodiment, the solid solution layer 20 is provided in all the internal electrode layers 12, but the present invention is not limited thereto, and the solid solution layer 20 may be provided only in some of the internal electrode layers 12.

[0024] (1st solid solution layer 21) The first solid solution layer 21 is provided at the interface with the dielectric layer 11 or the outer layer portion 13 in the curved portion 121. Although the present invention is not limited thereto, the first solid solution layer 21 has 0.2 mol to 0.8 mol of Sn dissolved in 100 mol of Ni. Ten points of the interface at the center of the stacking direction and the center of the width direction are measured by TEM analysis, and the average value is used. Here, the interface does not only refer to a boundary, but also refers to a region that may include a part of the internal electrode layer 12 and the dielectric layer 11 or the outer layer portion 13.

[0025] In the embodiment, the first solid solution layer 21 is provided only in the curved portion 121 of the internal electrode layer 12, but this is not limited thereto, and the first solid solution layer 21 may extend to the non-curved portion of the lead-out portion 12b or to the outer peripheral region of the opposing portion 12a.

[0026] (Second solid solution layer 22) The second solid solution layer 22 is provided at the interface with the dielectric layer 11 or the outer layer portion 13 in the central region of the facing portion 12a in the length direction L and width direction W. The central region is a region that is more central than a position that is 10 μm to 100 μm from the outer periphery of the facing portion 12a. Note that the central region of the facing portion 12a in the length direction L and width direction W is also the central region of the laminate 2 in the length direction L and width direction W.

[0027] The concentration of Sn relative to Ni in the second solid solution layer 22 is higher than that in the first solid solution layer 21. Although the present invention is not limited thereto, the second solid solution layer 22 is solid-dissolved with 1.5 mol to 2.5 mol of Sn relative to 100 mol of Ni. Ten points of the interface in the center of the stacking direction, the center of the width direction, and the center of the length direction are measured by TEM analysis, and the average value is used. Here, the interface does not only refer to a boundary, but also refers to a region that may include a part of the internal electrode layer 12 and the dielectric layer 11 or the outer layer portion 13.

[0028] (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.

[0029] (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.

[0030] (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.

[0031] 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.

[0032] (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.

[0033] (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).

[0034] (Paste printing process S2 for solid solution layer on one side) The one-surface-side solid solution layer paste printing step S2 includes a first solid solution layer paste printing step S21 and a second solid solution layer paste printing step S22.

[0035] (First solid solution layer paste printing process S21) 5(b), a paste 21P for a first solid solution layer is printed on the surface of the ceramic green sheet 101 for an inner layer portion. The paste 21P for a first solid solution layer is printed on an end region of the lead portion forming region Pb which will eventually become the lead portion 12b. In the embodiment, the paste 21P for a first solid solution layer contains 2.5 mol of Sn per 100 mol of Ni.

[0036] (Second solid solution layer paste printing process S22) 5(c), the second solid-solution layer paste 22P is printed on the surface of the inner layer ceramic green sheet 101. The second solid-solution layer paste 22P is printed in the center of the facing portion forming region Pa that will eventually become the facing portion 12a. The number of moles of Sn contained in the second solid-solution layer paste 22P per 100 moles of Ni is higher than the number of moles of Sn per 100 moles of Ni contained in the first solid-solution layer paste 21P. In the embodiment, the second solid-solution layer paste 22P contains 5 moles of Sn per 100 moles of Ni.

[0037] (Internal electrode layer paste printing process S3) Next, as shown in FIG. 5(d), the internal electrode layer paste 102, which will become the internal electrode layer 12, is printed in the internal electrode formation region P, which is the sum of the draw-out portion formation region Pb and the opposing portion formation region Pa, where the first solid solution layer paste 21P and the second solid solution layer paste 22P have been printed.

[0038] (Other side paste printing process S4) The other-surface paste printing step S4 also includes a first solid-solution layer paste printing step S41 and a second solid-solution layer paste printing step S42, similar to the one-surface solid-solution layer paste printing step S2.

[0039] (First solid solution layer paste printing process S41) First, as shown in FIG. 5(e), the first solid solution layer paste 21P is printed on the surface of the internal electrode layer paste 102.

[0040] (Second solid solution layer paste printing process S42) Subsequently, as shown in FIG. 5(f), the second solid solution layer paste 22P is printed on the surface of the internal electrode layer paste 102. Through the above steps, the laminated sheet 103 is produced.

[0041] (Lamination process S5) Next, in the lamination step S5, a plurality of laminate sheets 103 are laminated. Fig. 6 is a diagram for explaining the lamination step. As shown in the figure, a plurality of laminate sheets 103 are laminated so that the internal electrode formation regions P on which the internal electrode layer paste 102 is printed are shifted by half a pitch between adjacent laminate sheets 103. Furthermore, ceramic green sheets 112 for outer layers are laminated on both sides of the laminate sheets 103 that have been laminated.

[0042] (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.

[0043] (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.

[0044] (Formation of curved portion 121) In this laminate 2, in a region a certain distance in the longitudinal direction L from the portion that has been cut along the cutting line X to become the end face C of the laminate 2, portions of the laminate sheet 103 on which the internal electrode layer paste 102 is printed and portions on which it is not printed are alternately laminated, and the internal electrode layer paste 102 in this portion becomes the pull-out portion 12b. On the other hand, in an area spaced a certain distance or more from the end face C, only the portion of the laminate sheet 103 where the internal electrode layer paste 102 is printed is laminated, forming the facing portion 12a. That is, the region that becomes the drawn portion 12b has half the number of sheets of the internal electrode layer paste 102 compared to the region that becomes the facing portion 12a, and therefore has a thinner thickness in the stacking direction T. For this reason, a curved portion 121 that curves more toward the end face C side is formed in the end region on the end face C side of the drawn portion 12b.

[0045] (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.

[0046] (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, thereby producing the multilayer ceramic capacitor 1. At this time, the inner layer ceramic green sheets 101 and the outer layer ceramic green sheets 112 are sintered to become ceramics, and the dielectric layers 11 and the outer layer portions 13 are formed.

[0047] In this firing step S9, the internal electrode layer paste 102 becomes the internal electrode layer 12. Then, the first solid solution layer paste 21P and the second solid solution layer paste 22P printed on both sides of the internal electrode layer paste 102 in the lamination direction T are heated to become the first solid solution layer 21 and the second solid solution layer 22, respectively. The first solid solution layer 21 is formed at the interface with the dielectric layer 11 or the outer layer 13 in the end region of the pull-out portion 12b, and the second solid solution layer 22 is formed at the interface with the dielectric layer 11 or the outer layer 13 in the central region in the longitudinal direction L and width direction W of the opposing portion 12a.

[0048] 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 first solid solution layer 21 is formed at the interface on both sides of the curved portion 121 in the stacking direction T. This improves the strength of the curved portion 121, and improves the pressure resistance (voltage resistance) of the multilayer ceramic capacitor 1.

[0049] Furthermore, a second solid solution layer 22 is formed at the interface with the dielectric layer 11 or the outer layer portion 13 in the central region of the facing portion 12a in the length direction L and width direction W. This makes it possible to obtain high reliability when a voltage is applied.

[0050] 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]

[0051] 1. Multilayer ceramic capacitors 2. Laminate 3 External electrode 10 Inner Layer 11 Dielectric layer 12 Internal electrode layer 12A 1st internal electrode layer 12Aa 1st opposing part 12Ab 1st drawer 12B 2nd internal electrode layer 12Ba 2nd opposing part 12Bb 2nd drawer 12a Opposite part 12b Drawer part 13 Outer layer 20 Solid solution layer 21 1st solid solution layer 22 2nd solid solution layer 121 Curved section

Claims

1. A laminate in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately stacked, and two external electrodes are respectively arranged on two end faces of the laminate provided on both sides in a longitudinal direction, The internal electrode layer is a first internal electrode layer having an opposing portion opposing another internal electrode layer adjacent in the stacking direction, and a lead portion extending from the opposing portion to one of the end faces and connecting to the external electrode disposed on the one of the end faces; the facing portions and second internal electrode layers each having a lead portion extending from the facing portion to the other end face and connected to the external electrode disposed on the other end face are alternately arranged; a first solid-solution layer is provided at an interface with the dielectric layer in an end region of the lead portion on the side of the end surface, the first solid-solution layer being a first metal component that is a main component of the internal electrode layer and a second metal component different from the first metal component being in solid solution, the first solid-solution layer being provided in an end region of the lead portion on the side of the end surface, the first solid-solution layer being a first metal component that is a main component of the internal electrode layer, the second solid-solution layer being a second metal component different from the first metal component; a second solid-solution layer is provided at an interface between the dielectric layer and the facing portion in a central region in the length direction and the width direction of the facing portion, the second solid-solution layer being formed by dissolving the first metal component in the second metal component at a higher concentration than that of the first solid-solution layer; Electronic components.

2. the end region of the pull-out portion is a curved portion that is curved from the opposing portion toward the end surface toward a center portion in the stacking direction, The internal electrode layer furthest from the central portion in the stacking direction is a distance between a position of an end of the pull-out portion on the end face side in the stacking direction and a position of the opposing portion in the stacking direction is 5 μm or more and 50 μm or less; The electronic component according to claim 1 .

3. The first solid solution layer has a second metal component in a solid solution state of 0.2 mol to 0.8 mol per 100 mol of the first metal component. The electronic component according to claim 1 .

4. The first solid solution layer has a second metal component in a solid solution state of 0.2 mol to 0.8 mol per 100 mol of the first metal component. The electronic component according to claim 2 .

5. The second solid solution layer has the second metal component dissolved therein in an amount of 1.5 mol to 2.5 mol per 100 mol of the first metal component. The electronic component according to any one of claims 1 to 4.

6. The thickness of the internal electrode layer is 0.3 μm or more and 0.8 μm or less. The electronic component according to any one of claims 1 to 4.

7. The thickness of the dielectric layer is 0.3 μm or more and 0.8 μm or less. The electronic component according to any one of claims 1 to 4.

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

9. 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.

10. The thickness of the first solid solution layer and the second 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.

11. The length direction dimension is 0.09 mm or more and 1.1 mm or less, The width direction dimension is 0.004 mm or more and 0.6 mm or less, The thickness direction dimension is 0.004 mm or more and 0.6 mm or less. The electronic component according to any one of claims 1 to 4.

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