Multilayer electronic component

Abstract

This multilayer electronic component has a laminate, a cover, and an external electrode. The laminate has dielectrics and internal electrodes that alternately overlap each other in the lamination direction. The cover overlaps the laminate in the lamination direction. The external electrode overlaps a surface of the cover on the opposite side from the laminate. The cover has an insulator and a base electrode. The base electrode overlaps the insulator on the side opposite from the laminate in the lamination direction, and has a surface that is located on the side opposite from the insulator in the lamination direction and is in contact with the external electrode. The base electrode has one or more oxidation regions. The one or more oxidation regions include at least one contact oxidation region that is in contact with the insulator.

Description

Multilayer electronic components

[0001] This disclosure relates to multilayer electronic components such as multilayer ceramic capacitors.

[0002] Multilayer ceramic capacitors are known that have a laminate in which internal electrodes and dielectrics are alternately stacked (for example, Patent Document 1 below). The multilayer ceramic capacitor of Patent Document 1 has, in addition to the above laminate, a protective part that overlaps the upper and lower surfaces of the laminate, and an external electrode connected to the internal electrode. The external electrode covers the surface of the protective part opposite to the laminate, as well as the sides of the laminate and the protective part. The external electrode also has a base electrode layer and a plating layer that covers the base electrode layer.

[0003] To avoid confusion, it should be noted that in the description of the embodiments relating to this disclosure, which will be discussed later, the base electrode is not considered a component included in the external electrode, but rather a component included in the cover that overlaps the laminate.

[0004] Japanese Patent Publication No. 2024-108392

[0005] A multilayer electronic component according to one aspect of the present disclosure comprises a laminate, a cover, and an external electrode. The laminate has dielectrics and internal electrodes that alternately overlap in the stacking direction. The cover overlaps the laminate in the stacking direction. The external electrode overlaps the side of the cover opposite to the laminate. The cover comprises an insulator and a base electrode that overlaps the insulator on the side opposite to the laminate in the stacking direction, and whose side opposite to the insulator in the stacking direction is in contact with the external electrode. The base electrode has one or more oxidation regions. The one or more oxidation regions include at least one contact oxidation region in contact with the insulator.

[0006] A perspective view showing a capacitor according to the first embodiment. A schematic exploded perspective view of the main body of the capacitor in Figure 1. A cross-sectional view along line III-III in Figure 1. A cross-sectional view showing an example of the area of ​​the oxidation region. A cross-sectional view showing a capacitor according to the second embodiment. An enlarged view of a part of Figure 5. A cross-sectional view showing a capacitor according to the third embodiment. A perspective view showing a capacitor according to the fourth embodiment.

[0007] The embodiments relating to this disclosure will be described below with reference to the drawings. The figures used in the following description are schematic. Therefore, for example, the dimensional ratios on the drawings do not necessarily match those of reality. Also, the dimensional ratios may not match between drawings. Certain shapes and / or dimensions may be exaggerated, or details may be omitted. However, the above does not negate the fact that the actual shape and / or dimensions may be as shown in the drawings, or that the characteristics of the shape and / or dimensions may be extracted from the drawings.

[0008] Regarding aspects described relatively later, only the differences from aspects described relatively earlier will be mentioned. Unless otherwise specified, matters may be treated the same as those described earlier, or inferred from those aspects. Multiple aspects may be combined as appropriate. From another perspective, regardless of the order of explanation, an explanation of one aspect may be applied to other aspects, provided that no contradictions arise. For convenience, the same symbols may be used for corresponding components in different aspects, even if there are differences.

[0009] In the following explanation, when we refer to a "rectangle" (or "rectangular"), "square" (or "square-shaped"), and "rectangle" (or "rectangular"), the corners may be chamfered by curved surfaces, etc. Naturally, when viewed microscopically, the corners may be rounded due to manufacturing precision (errors). The same applies to other polygons, etc.

[0010] When referring to the thickness of various layers, unless otherwise specified, it refers to the thickness of the portion where the thickness is constant. For example, as will be described later, the base electrode is basically a layer of constant thickness, but it may be a configuration in which the thickness can be considered to change at the edges. However, when referring to the base electrode being thicker than the internal electrode, unless otherwise specified, such changes in thickness at the edges are not taken into consideration.

[0011] (Outline of Embodiments) Figure 1 is a perspective view showing a capacitor 1 (an example of a multilayer electronic component) according to the first embodiment. For convenience, Figure 1 and other figures described later are shown with a Cartesian coordinate system D1, D2, and D3. The capacitor 1 may be used with either the top or bottom facing upwards. However, for convenience in describing the embodiments, the +D3 side may be considered upwards, and terms such as top surface and bottom surface may be used.

[0012] Capacitor 1 is, for example, a multilayer ceramic capacitor. Capacitor 1 has a roughly rectangular parallelepiped body 3 and four external electrodes 5 located at the four corners of the body 3 in a plan view (viewed in the D3 direction). The external electrodes 5 contribute to the electrical connection between capacitor 1 and other electronic components (for example, a circuit board not shown).

[0013] Figure 3 is a cross-sectional view taken along the line III-III in Figure 1. Note that Figure 3 shows the D1D3 cross-section where the external electrode 5 on the +D2 side is cut. However, the D1D3 cross-section where the external electrode 5 on the -D2 side is cut, the D2D3 cross-section where the external electrode 5 on the -D1 side is cut, and the D2D3 cross-section where the external electrode 5 on the +D1 side is cut are basically the same. In describing the embodiments, for convenience, the terms D1, D2, and D3 may be used to describe the positional relationships between components, etc., assuming the cross-section shown in Figure 3, without further explanation.

[0014] The main body 3 includes, for example, a laminate 7 and two covers 9 that overlap the upper and lower surfaces of the laminate 7, respectively. The laminate 7 has a plurality of dielectrics 11 and a plurality of internal electrodes 13 that are alternately stacked. The internal electrodes 13 are electrically connected to the external electrodes 5. The laminate 7 directly performs the function of a capacitor. The covers 9 contribute, for example, to the electrical and / or structural protection of the laminate 7.

[0015] Each cover 9 has an insulator 15 that overlaps the laminate 7, and a base electrode 17 that overlaps the insulator 15 on the opposite side from the laminate 7 in the D3 direction. In other words, the base electrode 17 overlaps a portion of the insulator 15 (the four corner portions in a plan view) on the opposite side from the laminate 7. Also, the surface of the base electrode 17 opposite to the insulator 15 in the D3 direction is in contact with (covered by) the external electrode. In other words, the surface of the base electrode 17 opposite to the aforementioned portion of the insulator 15 is in contact with (covered by) the external electrode. The base electrode 17 contributes, for example, to depositing the metal that will become the external electrode 5 by a plating method, and / or to improving the adhesion force of the external electrode 5 to the main body 3.

[0016] Let us focus on each base electrode 17. Note that the explanation focusing on each base electrode 17 does not necessarily have to hold true for all base electrodes 17. Each base electrode 17 has one or more (one in the example in Figure 3) oxidation regions 23. The part of the base electrode 17 other than the oxidation region 23 (to put it simply, the non-oxidation region) will be referred to as the main region 21.

[0017] In each base electrode 17, one or more oxidation regions 23 include a contact oxidation region 23A that is in contact with the insulator 15. As will be described later, in the capacitor 1 according to this embodiment, oxidation regions 23 that are not in contact with the insulator 15 do not exist, or their number is small compared to the contact oxidation regions 23A (or their volume and / or cross-sectional area is small). Reflecting this, oxidation regions 23 other than the contact oxidation regions 23A are not shown in Figure 3.

[0018] The presence of the contact oxidation region 23A may provide appropriate effects.

[0019] For example, consider a configuration in which the insulator 15 is made of an inorganic material such as ceramics. Generally, inorganic materials have a lower coefficient of thermal expansion than metals. Also, generally, when metals are oxidized, the interatomic bonds become stronger, and the coefficient of thermal expansion decreases. Therefore, compared to the case where the insulator 15 and the non-oxidized metal (main region 21) of the base electrode 17 are in contact, the presence of a contact oxidation region 23A between them reduces the probability of a rapid change in the coefficient of thermal expansion from the insulator 15 to the interior side (main region 21) of the base electrode 17. As a result, the probability of the base electrode 17 delaminating from the insulator 15 due to the difference in thermal expansion is reduced. Consequently, the probability of the external electrode 5 delaminating together with the base electrode 17 is reduced.

[0020] Furthermore, for example, metals generally become less conductive when oxidized. This can be seen as an improvement in insulating properties. On the other hand, the insulator 15 is a component that contributes to the insulation of the internal electrode 13. The contact oxidation region 23A being in contact with the insulator 15 reinforces the insulating function of the insulator 15 compared to when a non-oxidized metal is in contact with the insulator 15. In the illustrated example, the base electrode 17 is not interposed between the internal electrode 13 and the external electrode 5. Therefore, even if the base electrode 17 has an oxidation region 23, the probability of the equivalent series resistance of the capacitor 1 becoming large is low.

[0021] It should be noted that the effects exemplified above do not necessarily have to be achieved. Furthermore, different technical ideas from the above-mentioned perspective may be extracted from this disclosure. In this case, the contact oxidation region 23A is not a mandatory requirement, nor is the base electrode 17 a mandatory requirement.

[0022] The above is an overview of the embodiments. A detailed explanation will be given in the following order: 1. First Embodiment (Figures 1 to 3) 1.1. Overall Configuration 1.2. Laminate 1.3. Cover (excluding the oxidation region) 1.4. External Electrode 1.5. Oxidation Region 1.5.1. Components and Measurement of the Oxidation Region 1.5.2. Geometric Configuration of the Oxidation Region 1.5.3. Comparison with the Oxidation Region of the Internal Electrode (Figure 4) 2. Second Embodiment (Figures 5 and 6) 3. Third Embodiment (Figure 7) 4. Fourth Embodiment (Figure 8) 5. Other Embodiments 6. Capacitor Manufacturing Method 7. Summary of Embodiments

[0023] (1. First Embodiment) (1.1. Overall Configuration) The capacitor 1 shown in Figure 1 is configured as, for example, a surface-mounted chip component. Specifically, for example, the capacitor 1 is positioned with its -D3 side or +D3 side facing a circuit board (not shown). The capacitor is then mounted on the circuit board by joining the four pads of the circuit board and the four external electrodes 5 with a conductive bonding material (for example, solder) (not shown).

[0024] The structure (internal structure and external shape) of capacitor 1 is, for example, generally symmetrical with respect to a plane of symmetry (not shown) that is parallel to the D1D2 plane and passes through the center of capacitor 1 in the thickness direction (D3 direction). Furthermore, the structure of capacitor 1 is, for example, 180° rotationally symmetrical when viewed in the D3 direction. Of course, capacitor 1 does not necessarily have to have such symmetries.

[0025] The shape of the main body 3 is, for example, generally a thin rectangular parallelepiped. This rectangular parallelepiped may be a square (as shown in the illustration) or a rectangle (excluding squares; the same applies hereinafter) when viewed from above. In the description of the embodiment, for convenience, the description may assume a square shape without further explanation.

[0026] The specific dimensions of the main body 3 (or capacitor 1) are arbitrary. For example, when the capacitor 1 is relatively small, the lengths in the D1 and D2 directions of the main body 3 (or capacitor 1) may be between 0.3 mm and 2.0 mm. When the length in the D1 direction is L and the length in the D2 direction is W, the ratio L / W may be between 0.5 and 2.0. The thickness in the D3 direction may be between 0.030 mm and 1.0 mm. If the surface of the main body 3 is not planar, for example, the maximum values ​​of the various dimensions may satisfy the above ranges (the same applies to the various dimensions of other components, unless contradictions arise).

[0027] Note that the example dimensions of each component described later are for the case where capacitor 1 is relatively small, unless otherwise specified. Therefore, larger (or smaller) dimensions than those exemplified may be used.

[0028] Multiple components of the same type (e.g., 5, 9, 11, 13, 15, or 17) may, unless otherwise specified and unless contradictions arise, be provided with the same (or corresponding) shape, size, material, and position as other components (except for relatively small differences; the same applies hereinafter). Therefore, unless otherwise specified and unless contradictions arise, the description of one component may be considered common to multiple components of the same type.

[0029] A single layered (film-like) component (for example, 5, 11, 13, 15, or 17) may be composed entirely of one type of material. However, it may also be composed of layers made of different materials stacked on top of each other. Furthermore, a component composed entirely of one type of material may, when considering the manufacturing process, be made from a single layer, or it may be composed of multiple layers made of the same type of material stacked on top of each other.

[0030] (1.2. Laminate) The shape of the laminate 7 shown in Figure 3 is, for example, generally a thin rectangular parallelepiped. Its planar shape is basically the same as the planar shape of the main body 3. The specific thickness of the laminate 7 is arbitrary. For example, the thickness of the laminate 7 may be 30% or more, 40% or more, or 50% or more of the thickness of the main body 3, and may also be 90% or less, 80% or less, or 70% or less. The above lower and upper limits may be combined in any way.

[0031] The dielectric 11 is basically a layered structure with a generally constant thickness (at least between the internal electrodes 13). The thickness of the dielectric 11 may be set appropriately according to the characteristics required of the capacitor 1. As an example of a relatively thin thickness, the thickness between adjacent internal electrodes 13 may be 0.1 μm or more or 0.5 μm or more, and may also be 3.0 μm or less, 2.0 μm or less, or 1.0 μm or less. The above lower and upper limits may be combined in any way. The shape and dimensions of the dielectric 11 in plan view are basically the same as the shape and dimensions of the laminate 7 in plan view. The material of the dielectric 11 is, for example, ceramics, and the specific type is also arbitrary. The number of layers of the dielectric 11 (internal electrodes 13) is arbitrary. For example, it may be 10 to 30 layers.

[0032] The internal electrodes 13 are layered and have a generally constant thickness. The thickness of the internal electrodes 13 is arbitrary; for example, it may be thinner than, the same as, or thicker than the thickness of the region between the internal electrodes 13 in the dielectric 11. As an example of a relatively thin thickness, the thickness of the internal electrodes 13 may be 0.3 μm or more or 0.5 μm or more, or it may be 3.0 μm or less, 2.0 μm or less, or 1.0 μm or less. The above lower and upper limits may be combined in any way. The material of the internal electrodes 13, either entirely or as a main component (for example, 60% by mass or more of the component; the same applies hereinafter), is, for example, a metal. The specific type of metal is arbitrary; for example, its entirety or main component is composed of one or more base metals (for example, Ni and / or Cu). The material of the internal electrodes 13 may also contain ceramics (common material).

[0033] Figure 2 is an exploded perspective view of the main body 3. Figure 2 is a schematic representation for understanding the planar shape and relative position of the internal electrodes 13, etc. Therefore, Figure 2 does not reflect the relative thicknesses of the various layers shown in Figure 3. Also, of the multiple dielectrics 11 and internal electrodes 13, only some of the dielectrics 11 and internal electrodes 13 are shown.

[0034] The internal electrode 13, for example, in a plan view, has a rectangular (square in the illustrated example) electrode body 13a and a pair of leading electrodes 13b extending from a pair of opposing corners of the electrode body 13a. The electrode body 13a is located inside the outer edge of the dielectric 11 and is not exposed from the side surface of the laminate 7. The pair of leading electrodes 13b reach the outer edge of the dielectric 11 and are connected to a pair of external electrodes 5 located at a pair of opposing corners of the main body 3. In the D3 direction, adjacent internal electrodes 13 are connected to different pairs of external electrodes 5. The dimensions of each part are arbitrary.

[0035] (1.3. Cover (excluding oxidation region)) The cover 9 shown in Figure 3 is, for example, a layered structure with a planar shape that overlaps with the laminate 7 without excess or deficiency. In the illustrated example, the thickness of the cover 9 is approximately constant. The ratio of the thickness of the cover 9 to the thickness of the main body 3 may be approximately the inverse of the ratio of the thickness of the laminate 7 to the thickness of the main body 3 (as described above). For example, in an embodiment in which covers 9 are provided on both sides in the D3 direction, the thickness of one cover 9 may be, for example, 5% or more, 10% or more, or 15% or more of the thickness of the main body 3, or 35% or less, 30% or less, or 25% or less. The above lower and upper limits may be combined in any way.

[0036] The insulator 15 is, for example, generally in a layered form having a planar shape that overlaps the laminate 7 without excess or deficiency. In the illustrated example, the thickness of the insulator 15 is generally constant in each of the arrangement region and the non-arrangement region of the base electrode 17. The thickness in the arrangement region of the base electrode 17 is thinner than the thickness in the non-arrangement region. The difference is generally equivalent to the thickness of the base electrode 17. The material of the insulator 15 is arbitrary. For example, the material of the insulator 15 may be the same as or different from the material of the dielectric 11. Also, the material of the insulator 15 may be an inorganic material, an organic material, or a combination of both. The inorganic material may be, for example, ceramics or not ceramics. The specific type of ceramics is also arbitrary.

[0037] The thickness of the insulator 15 is arbitrary. For example, the thickness of the insulator 15 may be thicker (in the illustrated example), equivalent, or thinner than the thickness of the dielectric 11 (both being the thickness between conductor layers or the thickness of a region not overlapping the conductor layer. In this paragraph, the same applies hereinafter). For example, the thickness of the insulator 15 may be set to be 2 times or more, 3 times or more, or 5 times or more the thickness of the dielectric 11, and may also be set to be 20 times or less, 10 times or less, or 5 times or less. The above lower limit and upper limit may be combined with any arbitrary ones. Also, for example, the thickness of the insulator 15 may be set to be 1.0 μm or more or 2.0 μm or more, and may also be set to be 10.0 μm or 5.0 μm or less. The above lower limit and upper limit may be combined with any arbitrary ones. Note that the insulating layer overlapping the uppermost internal electrode 13 may be regarded as the insulator 15 instead of the dielectric 11 regardless of its material and thickness. The same applies to the insulating layer overlapping the lowermost internal electrode 13.

[0038] The base electrode 17 is, for example, layered with a roughly constant thickness. However, the shape of its ends is arbitrary. As shown in Figure 2, the base electrode 17 is, for example, rectangular (more specifically, square) in shape in a plan view, located at the corner of the rectangular (more specifically, square) main body 3. Also, as shown in Figure 3, the base electrode 17 is, for example, completely embedded in the insulator 15 in a cross section parallel to the lamination direction (D3 direction) of the laminate 7. Therefore, the base electrode 17 has two sides exposed to the outside from the cover 9 (insulator 15): the side opposite to the laminate 7 and the two sides corresponding to the two sides forming the corner of the main body 3. The exposed surface of the base electrode 17 is, for example, the surface that is entirely in contact with the external electrode 5. The other surface of the base electrode 17 is, for example, entirely in contact with the insulator 15.

[0039] Unlike the illustrated example, the base electrode 17 may be partially embedded in the insulator 15, or its entire thickness may not be embedded in the insulator 15. From another viewpoint, the side surface of the base electrode 17 that does not correspond to the side surface of the main body 3 may or may not contact the insulator 15 or the external electrode 5, and the area of ​​contact (or length in plan view or cross-sectional view) is arbitrary. Furthermore, the planar shape of the base electrode 17 is not limited to a rectangular shape. For example, if the corners of the main body 3 are significantly chamfered by a curved surface in plan view, the side surface of the base electrode 17 corresponding to the side surface of the main body 3 (the side surface that contacts the external electrode 5) may also be curved. Also, for example, the side surface of the base electrode 17 that does not correspond to the side surface of the main body 3 (the side surface that contacts the insulator 15 in the configuration in which the base electrode 17 is embedded in the insulator 15) may be a single straight line or a single curved line in plan view.

[0040] The cross-sectional shape of the end portion (side surface from another perspective) of the base electrode 17 is arbitrary. Consequently, the mode of contact (adhesion) (interface mode) between the base electrode 17 and the insulator 15 or the external electrode 5 in the direction (e.g., D1 direction) intersecting (e.g., orthogonal) in the D3 direction is also arbitrary. Examples are shown below. Note that the following description assumes the mode illustrated in FIG. 3 (the mode in which the entire thickness of the base electrode 17 is buried in the insulator 15). However, it may be applied to other modes as long as there is no contradiction. Also, in the following description, for convenience, without particular notice, the orthogonal coordinate system D1D2D3 may be referred to with focus on the base electrode 17 on the +D1 side and +D3 side of FIG. 3.

[0041] In the illustrated example, the end portion (+D1 side end portion) corresponding to the side surface of the main body portion 3 of the base electrode 17 (+D1 side and +D3 side) has a side surface facing the outside of the main body portion 3. This side surface has a shape in which a plane substantially parallel to the D3 direction is chamfered relatively largely by a curved surface on a part on the opposite side (+D3 side) to the laminate 7. Also, the end portion E1 of the base electrode 17 on the inner side (-D1 side) of the main body portion 3 has a side surface in a planar shape substantially parallel to the D3 direction.

[0042] Different from the illustrated example, the side surface (+D1 side side surface) of the end portion corresponding to the side surface of the main body portion 3 of the base electrode 17 (+D1 side and +D3 side) may be an inclined surface that is positioned more toward the inner side (-D1 side) of the main body portion 3 on the opposite side (+D3 side) to the laminate 7 as a whole. Also, the end portion (+D1 side end portion) corresponding to the side surface of the main body portion 3 of the base electrode 17 (+D1 side and +D3 side) may have a tapered shape that gradually becomes thinner toward the side (-D3 side) of the laminate 7 on the side (+D1 side) of the side surface of the main body portion 3. From another perspective, the above end portion may have a shape that is difficult to regard as having a side surface. The inclined surface or tapered surface may be planar or curved. <0000Furthermore, for example, the side surface of the inner (-D1 side) end E1 of the main body portion 3 of the base electrode 17 (+D1 side and +D3 side) may be an inclined surface located further inward (-D1 side) or further outward (+D1 side) of the main body portion 3 towards the opposite side (+D3 side) from the laminate 7. Also, the side surface of end E1 may have a shape in which two or more inclined surfaces are combined in the D1D3 cross section. In addition, end E1 may have a tapered shape that gradually thins from the laminate 7 side (-D3 side) and / or from the opposite side (+D3 side) towards the inner (-D1 side) of the main body portion 3. The inclined surface or tapered surface may be planar or curved.

[0044] Regardless of the type of surface (a surface parallel to the D3 direction, a chamfered surface, an inclined surface, a tapered surface, or other surface) the end portion (the end portion on the +D1 side) of the base electrode 17 (on the +D1 side and the +D3 side) corresponding to the side surface of the main body 3, that surface may (or may not) exhibit a relatively smooth flat or curved surface by polishing (for example, barrel polishing) as described later. Also, regardless of the type of surface (a surface parallel to the D3 direction, one or more inclined surfaces, a tapered surface, or other surface) the end portion E1 has, it may or may not have irregularities (for example, irregularities in the D1D3 cross section).

[0045] The dimensions of the base electrode 17 are arbitrary. For example, in a plan view (viewed in the D3 direction), the length of one side of the base electrode 17 may be less than 1 / 3 of the length of one side of the main body 3, or it may be 1 / 3 or more. The thickness of the base electrode 17 may be thicker than the thickness of the internal electrode 13 (as shown in the illustration), the same as, or thinner than. For example, the thickness of the base electrode 17 may be 2 times or more, 3 times or more, or 5 times or more the thickness of the internal electrode 13, or it may be 20 times or less, 10 times or less, or 5 times or less. The above lower and upper limits may be combined in any way so as not to cause contradictions. Also, for example, the thickness of the base electrode 17 may be 2.0 μm or more, 3.0 μm or more, or 5.0 μm or more, or it may be 20.0 μm or less, 10.0 μm or less, or 5.0 μm or less. The above lower and upper limits may be combined in any way so as not to cause contradictions. Furthermore, the thickness of the base electrode 17 may be thinner, equal to, or thicker than the thickness of the portion of the insulator 15 sandwiched between the base electrode 17 and the internal electrode 13 (or the dummy electrode described later) (see illustrated example).

[0046] The material of the base electrode 17 is arbitrary. The previously described explanation regarding the material of the internal electrode 13 may be applied to the base electrode 17. Furthermore, when such application is made, the material of the base electrode 17 may be the same as or different from the material of the internal electrode 13. Examples of the latter include cases where the type of main metal component is the same, but the component ratio is different, and / or the type of minor component is different. Note that whether or not there is a difference in the oxidation region between the internal electrode 13 and the base electrode 17 (for example, a difference in the area ratio of the oxidation region) is ignored in determining whether or not the materials of the two electrodes are the same.

[0047] (1.4. External Electrodes) The external electrodes 5 are, for example, layered and have a basically constant thickness. As shown in Figure 1, the external electrodes 5 cover the four surfaces (top, bottom, and two sides) of the main body 3, for example, at the corners in a plan view of the main body 3. This allows one external electrode 5 to be connected to one lead electrode 13b on two sides of the main body 3, and also allows surface mounting on either the top or bottom surface of the capacitor 1. The shape and dimensions of the portions of the external electrodes 5 on each surface are arbitrary. The planar shape of the portion of the external electrode 5 located on the top or bottom surface of the main body 3 is, for example, rectangular (square in the illustrated example). The planar shape and dimensions of the portion of the external electrode 5 located on the side surface of the main body 3 are, for example, rectangular with the same lateral length as the portion located on the top or bottom surface.

[0048] The thickness of the external electrode 5 is arbitrary. For example, the thickness of the external electrode 5 may be greater than the thickness of the internal electrode 13 and the base electrode 17. For example, the thickness of the external electrode 5 may be 1.2 times or more, 2 times or more, or 3 times or more the thickness of the base electrode 17, or it may be 10 times or less, 5 times or less, or 3 times or less. The above lower and upper limits may be combined in any way. Also, for example, the thickness of the external electrode 5 may be 3 μm or more, 5 μm or more, or 10 μm or more, or it may be 30 μm or less, 20 μm or less, or 10 μm or less. The above lower and upper limits may be combined in any way so as not to cause any contradictions.

[0049] The material of the external electrode 5 is, for example, a metal. The specific type of metal is arbitrary; for example, all or the main component may be a base metal (e.g., Ni and / or Cu). The external electrode 5 may also be constructed by laminating different materials as needed. For example, the external electrode 5 may be constructed by laminating Cu, Ni, and Sn from the side of the base electrode 17. All or the main component of the material of the external electrode 5 may be the same as or different from the main component of the material of the internal electrode 13 and / or the main component of the material of the base electrode 17.

[0050] In the example shown in Figure 3, the external electrode 5 is constructed by laminating the first layer 5a to the fourth layer 5d from the side of the base electrode 17. The first layer 5a is a Cu layer formed by electroless plating. The second layer 5b is a Cu layer formed by electroplating. The third layer 5c is a Ni layer formed by electroplating. The fourth layer 5d is a Sn layer formed by electroplating. Note that the first layer 5a and the second layer 5b may be considered as a single Cu layer. The absolute value (μm) of the thickness of each layer and their relative sizes are arbitrary.

[0051] (1.5. Oxidation Region) (1.5.1. Composition and Measurement of the Oxidation Region) In the oxidation region 23 shown in Figure 3, the metals that constitute the main components of the main region 21 and / or the base electrode 17 (hereinafter, for convenience, only one of the terms may be used, but the two may be substituted unless contradictions arise) are composed of oxides that have been oxidized. For example, when all or part of the main components of the main region 21 is Ni, the oxidation region 23 contains nickel oxide. Nickel oxide is, for example, NiO, Ni ２ O ３ and / or NiO ２ Furthermore, when all or part of the main component of the main region 21 is Cu, the oxidized region 23 contains copper oxide. Copper oxide is, for example, Cu ２ O, CuO and / or CuO ２ That is the case.

[0052] The oxidation region 23 can be observed, for example, by SEM (Scanning Electron Microscope) and EDS (Energy Dispersive X-ray Spectroscopy). Specifically, when the oxidation region 23 is observed with SEM at an appropriate magnification, it is observed as a region exhibiting a different hue from the region other than the oxidation region 23 (main region 21) (hereinafter referred to as the heterochromatic region). Furthermore, if the presence of the main component elements of the base electrode 17 and oxygen elements is confirmed by EDS at the spot where the heterochromatic region identified by SEM is located, then that heterochromatic region can be said to be the oxidation region 23 where the base electrode 17 has been oxidized. By identifying the range of the heterochromatic region with SEM, the range of the oxidation region 23 and the dimensions of that range can be measured.

[0053] Methods for confirming the presence of oxygen using EDS include, for example, point analysis or mapping analysis. For example, point analysis can be used to confirm the presence of oxygen in the heterochromatic region by examining the spectrum of oxygen from the spot where the heterochromatic region is located. Alternatively, mapping analysis can be used to confirm the presence of oxygen in the heterochromatic region by confirming that the oxygen concentration at the spot where the heterochromatic region is located is greater than the oxygen concentration in the region of the base electrode 17 other than the heterochromatic region. This is because it is unreasonable to consider the oxidation region 23 as known based on the unavoidable and trace amount of oxygen present in known technology.

[0054] As a method for confirming the presence of the main component element of the base electrode 17, the point analysis or mapping analysis described above can be used. In this paragraph, Ni will be used as an example of the main component element of the base electrode 17. For example, by point analysis, the presence of Ni in the different colored phase region can be confirmed by checking the spectrum of Ni from the spot where the different colored phase region is located. Alternatively, by mapping analysis, for example, the presence of Ni in the different colored phase region can be confirmed by confirming that the concentration of Ni at the spot where the different colored phase region is located is greater than the concentration of Ni in the insulator 15.

[0055] In the mapping analysis described above, the area used to calculate the oxygen concentration can be set as appropriate. For example, the oxygen concentration can be calculated for each predetermined unit area in a cross section parallel to the D3 direction (e.g., a D1D3 cross section) as shown in Figure 3. The unit area can be set to an appropriate size. For example, the unit area could be 0.01 μm. ２ (Or an even smaller area may be used.) Depending on the situation, the unit area may be larger than the above (i.e., the precision may be lower). The shape of each unit area may be, for example, a square (e.g., a square of 0.1 μm × 0.1 μm).

[0056] For observing the oxidation region 23, for example, the JEOL JSM-6010LV can be used as an SEM-EDS analyzer.

[0057] (1.5.2. Geometric configuration of the oxidation region) The base electrode 17 may have only one oxidation region 23 in a predetermined cross section parallel to the D3 direction as shown in Figure 3, or in the entire three-dimensional structure of the base electrode 17 (hereinafter the same applies in this paragraph) (as shown in the example), or it may have multiple oxidation regions 23. Furthermore, the base electrode 17 may have only one contact oxidation region 23A (as shown in the example), or it may have multiple contact oxidation regions 23A (see Figure 5 described later).

[0058] In a predetermined cross-section parallel to the D3 direction as shown in Figure 3, or in the entire three-dimensional structure of the base electrode 17 (hereinafter the same applies in this paragraph), one or more oxidation regions 23 may or may not have oxidation regions 23 other than the contact oxidation region 23A (not shown as previously described) (illustrated example). Examples of oxidation regions 23 other than the contact oxidation region 23A include oxidation regions 23 that are in contact with the external electrode 5 but not with the insulator 15, and oxidation regions 23 that are not in contact with either the insulator 15 or the external electrode 5. Furthermore, one or more oxidation regions 23 may or may not have oxidation regions 23 that are in contact with the external electrode 5 (including those that are in contact with both the insulator 15 and the external electrode 5) (illustrated example).

[0059] In a predetermined cross-section parallel to the D3 direction as shown in Figure 3, the ratio of the total area of ​​the oxidation region 23 to the area of ​​the base electrode 17 is arbitrary. For example, this ratio may be 0.1% or more, 0.5% or more, or 1% or more, and may also be 50% or less, 20% or less, 10% or less, or 5% or less. The above lower and upper limits may be combined in any way so as not to cause any contradiction. The above examples of the range of ratios may also be applied to the ratio of the total area of ​​the contact oxidation region 23A to the area of ​​the base electrode 17.

[0060] Furthermore, the ratio of the total volume of the oxidation region 23 to the total volume of the base electrode 17 in the three-dimensional whole of the base electrode 17 is also arbitrary. For example, this ratio may be within the range obtained by squaring the above area ratio (0.0001% or more, 0.0025% or more, or 0.01% or more, and / or 25% or less, 4% or less, 1% or less, or 0.25% or less). An example of the above ratio range may also be applied to the ratio of the total volume of the contact oxidation region 23A to the volume of the base electrode 17.

[0061] In a predetermined cross-section parallel to the D3 direction as shown in Figure 3, the ratio of the total area of ​​the contact oxidation region 23A to the total area of ​​the oxidation region 23 is arbitrary. For example, this ratio may be less than 50%, 50% or more, 60% or more, 80% or more, 90% or more, or 100%.

[0062] In the three-dimensional whole of the base electrode 17, the ratio of the total volume of the contact oxidation region 23A to the total volume of the oxidation region 23 is also arbitrary. For example, this ratio may be within a range obtained by roughly squaring the above area ratio (less than 25%, 25% or more, 35% or more, 65% or more, 80% or more, or 100%).

[0063] In a predetermined cross-section parallel to the D3 direction as shown in Figure 3, the total length Lc of the oxidation region 23 (contact oxidation region 23A) in contact with the insulator 15 may be shorter, equal to, or longer than the total length (indicated) of the oxidation region 23 (which may include the contact oxidation region 23A) in contact with the external electrode 5. The ratio or difference between the two when the former is longer than the latter is also arbitrary. For example, the total length Lc may be 1.2 times or more, 2 times or more, 5 times or more, or 10 times or more than the total length of the oxidation region 23 in contact with the external electrode 5.

[0064] Furthermore, when considering the depth direction (D2 direction) of a predetermined cross section (D1D3 cross section) parallel to the D3 direction as shown in Figure 3, the total area in contact with the insulator 15 of the oxidation region 23 may be smaller, equal to, or larger than the total area in contact with the external electrode 5 of the oxidation region 23. The ratio or difference between the two when the former is larger than the latter is also arbitrary. For example, the total area in contact with the insulator 15 of the oxidation region 23 may be approximately the square of the ratio of the lengths mentioned above (1.4 times or more, 4 times or more, 25 times or more, or 100 times or more) of the total area in contact with the external electrode 5 of the oxidation region 23.

[0065] For clarification, it should be noted that if the total length Lc is longer than the total length of the oxidation region 23 in contact with the external electrode 5, or greater than a predetermined multiplier, then the latter total length is also included. The same applies to other comparison targets (area, volume, oxidation regions of other electrodes, etc.).

[0066] In a predetermined cross-section parallel to the D3 direction as shown in Figure 3, one or more oxidation regions 23 may be unevenly distributed within the base electrode 17. For example, the base electrode 17 is divided into three equal parts in the D3 direction. Then, the total area of ​​the oxidation regions 23 (or the ratio of the total area to the area of ​​each section; the same applies hereinafter) is compared among the three divided sections. In this case, the section closest to the laminate 7 may have the largest total area of ​​oxidation regions 23, and / or the section in contact with the external electrode 5 may have the smallest total area of ​​oxidation regions 23. In the above description, the division into three equal parts may be two, four, or five equal parts, etc. Furthermore, the description in this paragraph may be applied to the total three-dimensional volume of the base electrode 17.

[0067] The explanation in the previous paragraph may also be applied to a direction (D1 direction) perpendicular to the D3 direction within a predetermined cross-section (D1D3 cross-section). That is, the direction in which the base electrode 17 is equally divided is defined as the D1 direction. The total area of ​​the oxidation region 23 may be largest in the section including the end E1 embedded in the insulator 15, and / or the total area of ​​the oxidation region 23 may be smallest in the section in contact with the external electrode 5. Furthermore, the explanation in the previous paragraph may also be applied to the total three-dimensional volume of the base electrode 17. In this case, the direction in which the base electrode 17 is equally divided may be any direction (for example, the D1 direction or the D2 direction) in which one end is in contact with (embedded in) the insulator 15 and the other end is in contact with the external electrode 5.

[0068] In the example shown in Figure 3, the contact oxidation region 23A is a layered (film-like) area that extends over the entire surface of the base electrode 17 in contact with the insulator 15. That is, the contact oxidation region 23A has a portion that extends over the entire surface of the base electrode 17 on the side facing the laminate 7 (-D3 side or +D3 side), and also has a portion located at the end E1 embedded in the insulator 15. As previously described, the end E1 may have a shape that makes it difficult to perceive it as having a side surface. Furthermore, in three dimensions, the end E1 is located not only in the D1D3 cross section (Figure 3), but also on the inside of the main body 3 in the D2D3 cross section (+D2 side or -D2 side).

[0069] In the above embodiment, the thickness of the contact oxidation region 23A may be approximately constant or not. Furthermore, if it is not constant, the thickness of the portion of the contact oxidation region 23A located on the laminate 7 side relative to the main region 21 (in the D3 direction) and the thickness of the portion of the contact oxidation region 23A located at the end E1 (in the D1 direction) may be thicker than the other. In the illustrated example, the former is thinner than the latter.

[0070] The specific thickness of the portion of the contact oxidation region 23A located on the laminate 7 side relative to the main region 21 is arbitrary. For example, the thickness of this portion may be 1% or more, 5% or more, 10% or more, or 20% or more relative to the thickness of the base electrode 17, or it may be 80% or less, 60% or less, 50% or less, 40% or less, or 30% or less. The above lower and upper limits may be combined in any way. Also, for example, the thickness of this portion may be 0.5 μm or more, 1.0 μm or more, or 2.0 μm or more, or it may be 10 μm or less, 5 μm or less, or 3 μm or less. The above lower and upper limits may be combined in any way.

[0071] The specific size of the thickness (in the D1 direction) of the portion located at the end E1 of the contact oxidation region 23A is also arbitrary. In a predetermined direction (D1 direction) perpendicular to the D3 direction, the length of the portion may be 0.5% or more, 1.0% or more, or 2.0% or more of the length of the base electrode 17, and may also be 30% or less, 20% or less, or 10% or less. The above lower and upper limits may be combined in any way. Also, for example, the thickness of the portion may be 1 μm or more, 2 μm or more, or 5 μm or more, and may also be 20 μm or less, 15 μm or less, or 10 μm or less. The above lower and upper limits may be combined in any way.

[0072] The above explanation describes the configuration of the oxidation region 23 in a cross section parallel to the D3 direction (for example, a D1D3 cross section) as shown in Figure 3. On the other hand, for example, there are countless D1D3 cross sections in the D2 direction. The configuration of the oxidation region 23 in a cross section perpendicular to a specific direction (for example, the D2 direction) (for example, a D1D3 cross section) (as described above and below) does not need to be established in all of the countless cross sections in the above specific direction.

[0073] For example, the configuration of the oxidation region 23 described above or below may exist only in any cross-section excluding the specific cross-section. The specific cross-section, for example, with respect to the D1D3 cross-section, can be the cross-section located at the -D2 side or +D2 side end of the base electrode 17. The arbitrary cross-section may be, for example, an average or representative cross-section; for example, with respect to the D1D3 cross-section, it can be the central cross-section in the D2 direction of the base electrode 17.

[0074] Furthermore, for example, the configuration in a cross section perpendicular to a specific direction (e.g., the D2 direction) (e.g., the D1D3 cross section) may be established in a range of 1 / 3 or more, 1 / 2 or more or 2 / 3 or more of the length of the base electrode 17 in the specific direction. These ranges may be set so as to exclude the specific cross section described above. Of course, the configuration in the cross section may be established over the entire length of the base electrode 17 in the specific direction.

[0075] Whether the configuration relating to the oxidation region 23 is established within the length range described above can be determined, for example, based on images of a predetermined number (e.g., 3, 5, or 10) of cross-sections (e.g., D1D3 cross-sections) perpendicular to a specific direction, set at equal distances from the length of the base electrode 17 in a specific direction (e.g., the D2 direction). If it is difficult to extract images of multiple cross-sections from a single capacitor 1, images of multiple cross-sections can be extracted from multiple capacitors 1 of the same type.

[0076] Furthermore, the configuration of the oxidation region 23, etc., described above or below does not have to be established for all (in this case, eight) of the base electrodes 17 (although it may be established). For example, the configuration of the oxidation region 23, etc., may be established for at least one, half or two-thirds or more of the base electrodes 17.

[0077] Similarly, the configuration for comparing the base electrode 17 with other electrodes (for example, the internal electrode 13), as described later, does not need to be valid for all other electrodes. For example, the configuration for comparison may be valid for comparison with at least one, more than half, or more than two-thirds of the other electrodes.

[0078] (1.5.3. Comparison with the Oxidation Region of the Internal Electrode) Figure 4 is a cross-sectional view illustrating the oxidation region 23 of the base electrode 17 in comparison with the oxidation region 13x of the internal electrode 13. The upper and lower panels of Figure 4 correspond to parts of the +D1 and +D3 sides of Figure 3, respectively.

[0079] The internal electrode 13 may or may not have an oxidation region 13x. The explanation in Section 1.5.1 (explanation of the components and measurement of the oxidation region 23) may be applied to the oxidation region 13x. However, for example, the term "underlay electrode 17" should be replaced with the term "internal electrode 13". Also, the term "insulator 15" should be replaced with the term "insulator 15" or "dielectric 11".

[0080] The geometric configuration of the oxidation regions 13x, including their number, position, shape, and dimensions, is arbitrary. In the lower part of Figure 4, an example of an oxidation region 13x having a size that extends across the entire thickness of the internal electrode 13 is shown. Unlike the illustrated example, for example, the oxidation regions 13x may be located only on the upper or lower side of the internal electrode 13. Furthermore, the aspect ratio and specific dimensions of the oxidation regions 13x are also arbitrary.

[0081] In a cross-section parallel to the D3 direction (D1D3 cross-section), the ratio of the total area of ​​the oxidation region 23 to the area of ​​the base electrode 17 (hereinafter sometimes simply referred to as the "area ratio of oxidation region 23") may be larger than (upper example in Figure 4), equal to (not shown), or smaller than (lower example in Figure 4) the ratio of the total area of ​​the oxidation region 13x to the area of ​​the internal electrode 13 (hereinafter sometimes simply referred to as the "area ratio of oxidation region 13x").

[0082] In the upper part of Figure 4, an example is shown in which the internal electrode 13 does not have an oxidation region 13x. Of course, the internal electrode 13 may have an oxidation region 13x, while the area ratio of the oxidation region 23 is larger than the area ratio of the oxidation region 13x. In the lower part of the figure, the area ratio of the oxidation region 23 is smaller and the area ratio of the oxidation region 13x is larger compared to the upper part of the figure. However, the relative sizes of the two can be adjusted by adjusting the area ratio of either one of them.

[0083] When the area ratio of oxidation region 23 and the area ratio of oxidation region 13x are different, the ratio or difference between the two is arbitrary. For example, the larger of the two may be 1.2 times or more, 1.5 times or more, 2.0 times or more, 5 times or more, or 10 times or more compared to the smaller one. Even when the value of the smaller one is 0, the ratio of the larger one to the smaller one is considered infinite and may be included in the above range. The same applies to other ratios, as long as no contradictions arise.

[0084] (2. Second Embodiment) Figure 5 is a cross-sectional view showing the capacitor 201 according to the second embodiment, and corresponds to Figure 3. Figure 6 is an enlarged view of a part of Figure 5 (the base electrode 217 on the +D1 and +D3 sides). In the following description, for convenience, unless otherwise specified, the terms D1, D2, and D3 may be used to describe the positional relationships between the components, focusing on the base electrode 217 on the +D1 and +D3 sides.

[0085] Capacitor 201 has a main body portion 203 which corresponds to the main body portion 3 of capacitor 1. The main body portion 203 has a cover 209 which corresponds to the cover 9 of the main body portion 3. The cover 209 has a base electrode 217 which corresponds to the base electrode 17 of the cover 9. The base electrode 217 has a main region 21, an oxidation region 23, a contact oxidation region 23A, and an end portion E1, etc., similar to the base electrode 17.

[0086] However, unlike the first embodiment, in each base electrode 217, one or more oxidation regions 23 (one or more contact oxidation regions 23A) are not located on the entire surface of the base electrode 217 that is in contact with the insulator 15. Also, from another viewpoint, each base electrode 217 has multiple oxidation regions 23 (contact oxidation regions 23A) that are separated from each other in a cross section parallel to the D3 direction, or in the entire three-dimensional structure of the base electrode 17.

[0087] Specifically, in the illustrated example, the multiple contact oxidation regions 23A include one or more (multiple in the illustrated example) main surface oxidation regions 23Ad located on the laminate 7 side (-D3 side or +D3 side) of the base electrode 217, and one or more (multiple in the illustrated example) end oxidation regions 23Ae located at the end E1. The base electrode 217 may have only one of the main surface oxidation regions 23Ad and the end oxidation regions 23Ae. Furthermore, there may or may not be a contact oxidation region 23A that combines both the main surface oxidation region 23Ad and the end oxidation region 23Ae (the contact oxidation region 23A on the -D1 side and -D3 side in Figure 6).

[0088] As already stated, the description of the first embodiment may be applied to the second embodiment, provided that no inconsistencies arise. For the sake of clarity, for example, the various numerical ranges described in Section 1.5.2 may also be applied to the second embodiment. Specifically, the various numerical ranges relate to the following parameters, for example: - The ratio of the total area of ​​the oxidation region 23 (or contact oxidation region 23A) to the area of ​​the base electrode 17. - The ratio of the total volume of the oxidation region 23 (or contact oxidation region 23A) to the total volume of the base electrode 17. - The ratio of the total area of ​​the contact oxidation region 23A to the total area of ​​the oxidation region 23. - The ratio of the total volume of the contact oxidation region 23A to the total volume of the oxidation region 23. - The ratio of the total length Lc of the contact oxidation region 23A in contact with the insulator 15 to the total length of the oxidation region 23 in contact with the external electrode 5. - The ratio of the total area of ​​the oxidation region 23 in contact with the insulator 15 to the total area of ​​the oxidation region 23 in contact with the external electrode 5. - The ratio of the thickness of the portion of the contact oxidation region 23A located on the laminate 7 side relative to the main region 21 to the thickness of the base electrode 17. - The thickness (μm) of the portion of the contact oxidation region 23A located on the laminate 7 side relative to the main region 21. - The ratio of the length of the portion of the contact oxidation region 23A located at the end E1 to the length of the base electrode 17 in a predetermined direction (D1 direction) perpendicular to the D3 direction. - The length (μm) of the portion of the contact oxidation region 23A located at the end E1 in the D1 direction.

[0089] Furthermore, for the sake of clarity, the explanation of which section has a larger area ratio or volume ratio of oxidation region 23 when the base electrode 17 is equally divided in the D3 direction or the D1 direction may also be applied to the second embodiment. The explanation of the comparison with the oxidation region 13x of the internal electrode 13 in Section 1.5.3 (including the ratio of area ratios) may also be applied to the second embodiment.

[0090] The number of main surface oxidation regions 23Ad is arbitrary; it may be zero, one, or multiple. Also, in a cross-section parallel to the D3 direction as shown in Figure 6, the total length Ld in the D1 direction where the main surface oxidation regions 23Ad (oxidation regions 23) are in contact with the insulator 15 is arbitrary. For example, the above total length may be 0.5% or more, 1.0% or more, 2.0% or more, or 5% or more of the length L0 of the base electrode 17 in the D1 direction. As can be understood from the first embodiment, the upper limit of the above total length ratio may be any value of 100% or less. However, the above total length ratio may be 50% or less, 30% or less, 20% or less, 10% or less, or 5% or less. The above lower and upper limits may be combined in any way so as not to cause contradictions or other issues.

[0091] In the illustrated example, since the main surface oxidation region 23Ad is depicted as rectangular, the length Ld in the D1 direction where the main surface oxidation region 23Ad is in contact with the insulator 15 is the same as the length (maximum value) of the main surface oxidation region 23Ad in the D1 direction. However, the two may be different. In the following explanation, the sign Ld may also be used for the latter. Furthermore, unless contradictions arise, the explanation for one of the two lengths described above may be applied to the other.

[0092] The shape and dimensions of each main surface oxidation region 23Ad are also arbitrary. For example, in a cross section parallel to the D3 direction (D1D3 cross section) as shown in Figure 6, the main surface oxidation region 23Ad has a maximum length Ld in the D1 direction that is longer than the maximum length Hd (thickness) in the D3 direction (it is flattened). Also, when considering the depth direction (D2 direction), the main surface oxidation region 23Ad is layered. Of course, the main surface oxidation region 23Ad does not have to have such a shape. Furthermore, the shape of the main surface oxidation region 23Ad may be roughly rectangular (e.g., a rectangle), or it may not be.

[0093] Ld / Hd is arbitrary. For example, in at least one main surface oxidation region 23A that covers more than half or two-thirds of the area, Ld / Hd may be 1.5 or more, 2.0 or more, or 3.0 or more, and may also be 20 or less, 10 or less, or 5 or less. The above upper and lower limits may be combined in any way. The values ​​(μm) of Ld and Hd are also arbitrary. For Hd, the explanation of the thickness (D3 direction) of the portion of the contact oxidation region 23A located on the laminate 7 side relative to the main region 21 in the first embodiment may be used. For Ld, the explanation of the length in the D1 direction of the portion of the contact oxidation region 23A located at the end E1 in the first embodiment may be used.

[0094] The number of end oxidation regions 23Ae is arbitrary; it may be zero, one, or multiple. Also, in a cross-section parallel to the D3 direction as shown in Figure 6, the total length He in the D3 direction where the end oxidation regions 23Ae (oxidation regions 23) are in contact with the insulator 15 is arbitrary. For example, the above total length may be 1% or more, 5% or more, or 10% or more of the thickness of the base electrode 17 in the D3 direction. As can be understood from the first embodiment, the upper limit of the above total length may be any value of 100% or less. However, the above total length may be 80% or less, 50% or less, 30% or less, or 20% or less. The above lower and upper limits may be combined in any way.

[0095] In the illustrated example, since the end oxidation region 23Ae is depicted as rectangular, the length He in the D3 direction where the end oxidation region 23Ae is in contact with the insulator 15 is the same as the length (maximum value) of the end oxidation region 23Ae in the D3 direction. However, the two may be different. In the following explanation, the sign He may also be used for the latter. Furthermore, unless contradictions arise, the explanation for one of the two lengths described above may be applied to the other.

[0096] The shape and dimensions of each end oxidation region 23Ae are also arbitrary. The descriptions of the shape of the main surface oxidation region 23Ad, the Ld / Hd ratio, and the Ld (μm) and Hd (μm) ratios may be used in conjunction with the description of the end oxidation region 23Ae. However, Ld is substituted with Le and Hd is substituted with He.

[0097] (3. Third Embodiment) Figure 7 is a cross-sectional view showing the capacitor 301 according to the third embodiment, and corresponds to Figure 3.

[0098] Capacitor 301 has a main body portion 303 that corresponds to the main body portion 3 of capacitor 1. The main body portion 303 has a cover 309 that corresponds to the cover 9 of the main body portion 3. The cover 309 has a base electrode 217 related to capacitor 201. Capacitor 301 may also have a base electrode 17 related to capacitor 1.

[0099] The capacitor 301 differs from the first and second embodiments in that the cover 309 has a dummy electrode 19. The dummy electrode 19 contributes, for example, to reinforcing the cover 309. Also, for example, the dummy electrode 19 is exposed on the side surface of the main body 303, which contributes to improving the bonding strength between the side surface and the external electrode 5, and / or to facilitating the formation of the external electrode 5 when it is formed by a plating method.

[0100] The capacitor 301 has, for example, a dummy electrode 19 between each base electrode 17 and the laminate 7. In the following, unless otherwise specified, expressions may be made assuming that we are focusing on the space between one base electrode 17 and the laminate 7.

[0101] In the example shown in Figure 7, only one dummy electrode 19 is provided between the base electrode 17 and the laminate 7. The dummy electrode 19 is insulated from the internal electrode 13 and the base electrode 17 by an insulator 15. Unlike the illustrated example, the dummy electrode 19 may be provided in multiple layers between the laminate 7 and the single base electrode 17, separated by the insulator 15. The cover 309 may be considered to have alternatingly stacked insulating layers (layers constituting the insulator 15) and electrode layers (one or more dummy electrodes 19 and base electrodes 17).

[0102] The dummy electrode 19 is layered and has a generally constant thickness. The position, shape, and dimensions of the dummy electrode 19 in a plan view may be the same as, for example, the base electrode 17. Therefore, for example, the side of the dummy electrode 19 corresponding to the side of the main body 303 is exposed from the main body 303. The thickness of the dummy electrode 19 is, for example, thicker than the thickness of the internal electrode 13 and thinner than the thickness of the base electrode 17. The difference or ratio of these thicknesses is arbitrary.

[0103] Although not specifically shown in the diagram, the dummy electrode 19 may or may not have an oxidation region. The explanation in Section 1.5.1 (explanation of the components and measurement of the oxidation region 23) may be applied to the oxidation region of the dummy electrode 19. Furthermore, the geometric configuration of the oxidation region of the dummy electrode 19, including the number, position, shape, and dimensions, is arbitrary. The explanation of the geometric configuration of the internal electrode 13 may be applied to the dummy electrode 19.

[0104] In a cross-section parallel to the D3 direction (D1D3 cross-section), the ratio of the total area of ​​the oxidation region 23 to the area of ​​the base electrode 17 may be greater than, equal to, or less than the ratio of the total area of ​​the oxidation region of the dummy electrode 19 to the area of ​​the dummy electrode 19. The ratio or difference between the two may also be arbitrary. For example, the larger of the two area ratios may be 1.2 times or more, 1.5 times or more, 2.0 times or more, 5 times or more, or 10 times or more compared to the smaller of the two.

[0105] (4. Fourth Embodiment) Figure 8 is a perspective view of the capacitor 401 according to the fourth embodiment. The cross-sectional views according to the first to third embodiments may be referenced as diagrams showing the D1D3 cross-section of the capacitor 401.

[0106] Generally speaking, capacitor 401 differs from capacitor 1, which is a four-terminal type (four external electrodes 5), in that it is a two-terminal type (two external electrodes 5). In such capacitor 401, as in the first to third embodiments, an oxidation region may be formed on the base electrode (not shown). The specific explanation regarding the oxidation region may also be applied to the fourth embodiment, as long as it does not create inconsistencies. The configuration of the two-terminal type capacitor 401 may be the same as known configurations, except for the configuration related to the oxidation region. The base electrode (not shown) has a planar shape that is approximately the same as (slightly smaller than) the portion located on the upper or lower surface of the external electrode 5.

[0107] (5. Fifth Embodiment) Although not specifically shown in the figures, other examples of capacitor configurations are given.

[0108] The capacitor is not limited to a four-terminal or two-terminal type, and may have three or five or more external electrodes 5. The arrangement of the external electrodes is also arbitrary. For example, the capacitor may have four external electrodes in total, on each short side and at the center of each long side of its rectangular body in plan view. Alternatively, for example, the capacitor may have six or more external electrodes along the outer edge of its rectangular body in plan view.

[0109] The capacitor may have an outer resin covering the entire structure as illustrated in Figure 1 or Figure 8, and lead wires connected to the external electrodes 5 and extending from the outer resin. In another view, the capacitor may be a through-hole mounting type rather than a surface-mount type. In such a embodiment, one external electrode 5 may cover only one side.

[0110] The two types of internal electrodes 13, each connected to a different external electrode 5, may be stacked alternately in pairs rather than one at a time. In this case, for example, the thickness of the dielectric 11 between two opposing internal electrodes 13 connected to the same external electrode 5 may be thinner than the thickness of the dielectric 11 between two opposing internal electrodes 13 connected to different external electrodes 5. As can be seen from this, the multiple dielectrics 11 do not have to have the same shape and size.

[0111] Furthermore, the two types of internal electrodes 13 connected to different external electrodes 5 do not necessarily have to face each other. For example, a circuit in which two parallel plate capacitors are connected in series may be configured by providing two types of internal electrodes 13 connected to different external electrodes 5 on the same layer, and providing an internal electrode 13 facing the two types of internal electrodes 13. Alternatively, a circuit in which three or more parallel plate capacitors are connected in series may be configured.

[0112] In the example shown in Figure 8, the portion of the edge of the internal electrode 13, for example, the portion on the -D2 side or the +D2 side (referred to as the "non-exposed edge" in this paragraph), is not exposed from the side of the main body 403. This non-exposed edge is covered by the portion of the dielectric 11 and insulator 15 that extends outward (towards the -D2 side or +D2 side) from the non-exposed edge. However, the non-exposed edge may also be covered by stacking another dielectric layer on the side (the -D2 side or +D2 side) of the laminated structure of the dielectric 11 and insulator 15, thereby preventing exposure. Thus, the main body or laminate does not need to be a laminated structure in its entirety.

[0113] Multilayer electronic components are not limited to capacitors. Other multilayer electronic components include, for example, multilayer inductors and multilayer filters. A multilayer filter may have, for example, an LC circuit. As can be seen from this example, a multilayer electronic component may implement two or more functions (capacitor and inductor). The parts that implement different functions may be different parts in a planar perspective and / or different parts in a side perspective.

[0114] (6. Method for Manufacturing Capacitors) Various methods may be used to manufacture capacitors 1, etc. For example, the general procedure may be the same as a known procedure. An example is shown below. Here, we will basically take as an example a configuration in which a dummy electrode 19 is provided (capacitor 301).

[0115] First, a ceramic green sheet to form the dielectric 11 and multiple ceramic green sheets to form each insulator 15 are manufactured. In an embodiment where dummy electrodes 19 are not provided, the insulator 15 can be made from a single ceramic green sheet. Next, a conductive paste to form the internal electrode 13, dummy electrode 19, or base electrode 17 is applied (for example, printed) to the ceramic green sheet. Next, the ceramic green sheets are laminated to produce a precursor for the main body 303. The lamination for producing the precursor for the laminate 7 and the lamination of the precursor for the cover 309 on the precursor for the laminate 7 may be performed together or separately.

[0116] Up to the point of fabricating the precursor of the main body portion 303 described above, the process is carried out using a base substrate of a size that allows for the creation of multiple main body portions 303. After the fabrication of the precursor, the base substrate containing the precursor is pieced into pieces (for example, cut) of a size roughly corresponding to the size of the main body portion 303. Next, a laminate having the size of the main body portion 303 is fired. After that, a metal film is formed on the main body portion 3 to form the external electrode 5.

[0117] Degreasing may be performed before firing. Firing may be carried out, for example, in a reducing atmosphere. Re-oxidation heat treatment may be performed after firing. Polishing (e.g., barrel polishing) of the main body 3 may be performed before and / or after firing. During polishing, for example, the edges of the main body 3 may be chamfered, or the sides of the main body 3 may be polished.

[0118] The external electrode 5 may be formed by various methods. For example, metal may be deposited on the surface of the base electrode 17 and on the exposed edges of the internal electrode 13 and dummy electrode 19 by electroless plating and / or electroplating. Alternatively, thin film formation methods such as the dip method, printing method, CVD (Chemical Vapor Deposition), or PVD (Physical Vapor Deposition) may be employed. As can be understood from the above, the base electrode 17 and dummy electrode 19 may or may not contribute to the deposition of metal.

[0119] The method for embedding all or part of the thickness of the base electrode 17 into the insulator 15 may be as appropriate.

[0120] For example, the ceramic green sheet constituting the insulator 15 may be realized by preparing a first ceramic green sheet on which a conductive paste that will serve as the base electrode 17 is layered, and a second ceramic green sheet which is layered on the first ceramic green sheet together with the base electrode 17 and the conductive paste, and has a notch at the position of the base electrode 17. The second ceramic green sheet may be a single ceramic green sheet or a laminate of multiple ceramic green sheets. The conductive paste that will serve as the base electrode 17 may be formed by a single application to the first ceramic green sheet before or after the lamination of the second ceramic green sheet, or by multiple applications.

[0121] Alternatively, or in addition to the above-described implementation method, the conductive paste that will serve as the base electrode 17 may be applied to the precursor of the main body 303 (or the precursor of the cover 309) and pressed in the D3 direction. The pressure from this pressing may cause the conductive paste that will serve as the base electrode 17 to sink into the precursor of the insulator 15.

[0122] The method for forming the oxidation region 23 (and other oxidation regions), and the method for adjusting the area ratio, etc., are arbitrary. For example, the degree of oxidation in the internal electrode 13, dummy electrode 19, or base electrode 17 may be adjusted by adjusting the amount of oxygen contained in the conductive paste before coating, and / or by adjusting the time the ceramic green sheet coated with the conductive paste is exposed to an oxidizing atmosphere before lamination. Also, for example, an oxidizing agent or reducing agent may be used at an appropriate time.

[0123] In the base electrode 17, it is also optional to form a contact oxidation region 23A or to make the oxidation region 23 unevenly distributed towards the insulator 15. For example, when layering multiple conductive pastes when forming the base electrode 17, the conductive paste layer printed at the position in contact with the insulator 15 may contain a larger amount of oxidizing agent than the conductive paste layers printed at other positions. In addition, a powdered or paste-like oxidizing agent may be placed on the surface of the ceramic green sheet that will become the insulator 15 in the area (or the entire surface) where the base electrode 17 is applied. Furthermore, oxygen emitted from the precursor of the insulator 15 during firing may be utilized. The firing temperature and firing atmosphere may be adjusted to enable such utilization. In addition, the precursor of the insulator 15 of the cover 9 may be, for example, BaTiO ３ It may contain crystalline powder particles mainly composed of and a desired oxidizing agent or sintering aid. Among these, for example, an oxidizing agent that is not present in the precursor of the dielectric 11 that contacts the internal electrode 13 contained in the laminate 7 may be added, or if an oxidizing agent is also added to the precursor of the dielectric 11 that contacts the internal electrode 13, more oxidizing agents may be added. Examples of oxidizing agents include MnO ２ Alternatively, MgO can be used. The formation of discrete contact oxidation regions 23A in the D3 or D1 direction can also be achieved by the above application.

[0124] (7. Summary of Embodiments) Below, the configuration of the stacked electronic component according to the embodiment is extracted, and the effects of the extracted configuration are illustrated. However, the effects illustrated below do not necessarily have to be achieved. Also, for convenience, reference numerals of one embodiment may be used to represent multiple embodiments below. However, the matters described below also apply to embodiments in which reference numerals are not used, unless there is a contradiction or other issue.

[0125] The capacitor 1 according to the embodiment has a laminate 7, a cover 9, and an external electrode 5. The laminate 7 has a dielectric 11 and an internal electrode 13 that are alternately stacked in the stacking direction (D3 direction). The cover 9 overlaps the laminate 7 in the D3 direction. The external electrode 5 overlaps the surface of the cover 9 opposite to the laminate 7. The cover 9 has an insulator 15 and a base electrode 17. The insulator 15 overlaps the laminate 7. The base electrode 17 overlaps the laminate 7 on the side opposite to the laminate 7 with respect to a partial region of the insulator 15, and the surface opposite to the partial region is in contact with the external electrode 5. Further, the base electrode 17 has one or more oxidation regions 23. The one or more oxidation regions 23 include at least one contact oxidation region 23A that contacts the insulator 15.

[0126] Therefore, for example, as described in the description of the outline of the embodiment, an effect of reducing the difference in thermal expansion coefficient and / or an effect of enhancing the insulation property of the insulator 15 is expected. Supplementary explanation regarding the reduction of the difference in thermal expansion coefficient. In the description of the embodiment, base metals (more specifically, Ni and Cu) are exemplified as the metal that is the main component of the base electrode 17. In a relatively high-temperature state, the thermal expansion coefficient of Ni is 16.8×10 －６ / K, and the thermal expansion coefficient of NiO is 14×10 －６ / K. Assuming BaTiO ３ as an example of the material of the insulator 15, in a relatively high-temperature state, the thermal expansion coefficient of BaTiO ３ is 11×10 －６ / K. Thus, the thermal expansion coefficient of the base electrode 17 can be made close to the thermal expansion coefficient of the insulator 15 by oxidation. Incidentally, in a relatively high-temperature state, the thermal expansion coefficient of Cu is 17.7×10 －６ / K.

[0127] A part of the outer edge of the base electrode 17 may be configured such that an end portion E1 (an example of a predetermined end portion) located on the central side of the capacitor 1 in a direction (for example, D1 direction) intersecting the D3 direction sinks toward the laminate 7 with respect to the insulator 15. The at least one contact oxidation region 23A may include a contact oxidation region 23A that is located at the end portion E1 and contacts the insulator 15 in a direction (for example, D1 direction) intersecting the D3 direction.

[0128] Normally, the outer edge of the base electrode 17 is prone to delamination. However, because the end portion E1 is embedded in the insulator 15, the likelihood of the end portion E1 becoming the starting point for delamination is reduced. Furthermore, it is expected that the reduction in the likelihood of delamination will be further enhanced by reducing the difference in thermal expansion coefficients in the contact oxidation region 23A of the end portion E1.

[0129] In a cross-section parallel to the D3 direction (for example, a D1D3 cross-section), the total length over which the oxidation region 23 of the base electrode 17 contacts the external electrode 5 may be shorter than the total length Lc over which the oxidation region 23 of the base electrode 17 contacts the insulator 15.

[0130] In this case, for example, when the external electrode 5 is formed by a plating method, the proportion of the oxidized region 23 on the surface of the base electrode 17 is relatively small, making it easier to deposit the metal that will become the external electrode 5 onto the base electrode 17. Also, for example, at the interface between the base electrode 17 and the external electrode 5, the ratio of the area in contact between the metals to the area in contact between the metal oxide and the metal becomes large, so it is expected that the bonding strength of both electrodes will improve due to the mutual diffusion of the metals.

[0131] In a cross-section parallel to the D3 direction (for example, a D1D3 cross-section), the ratio of the total area of ​​the oxidation region 23 of the base electrode 17 to the area of ​​the base electrode 17 may be greater than the ratio of the total area of ​​the oxidation region 13x of the internal electrode 13 to the area of ​​the internal electrode 13 (upper panel of Figure 4).

[0132] In this case, for example, the above-mentioned effect can be improved with respect to the base electrode 17. On the other hand, with respect to the internal electrode 13, the probability of the equivalent series resistance increasing due to the oxidation region 13x is reduced. As mentioned in the overview of the embodiment, even if the oxidation region 23 increases, the probability of the equivalent series resistance of the capacitor 1 increasing is low.

[0133] Conversely, in a cross-section parallel to the D3 direction, the ratio of the total area of ​​the oxidation region 23 of the base electrode 17 to the area of ​​the base electrode 17 may be smaller than the ratio of the total area of ​​the oxidation region 13x of the internal electrode 13 to the area of ​​the internal electrode 13 (lower panel of Figure 4).

[0134] Generally, metals expand in volume when oxidized. Since the internal electrode 13 is sandwiched between the dielectric 11, it is expected that the fixation to the dielectric 11 will be strengthened by the volume expansion. And / or, the gap between the dielectric 11 and the internal electrode 13 will be sealed by the volume expansion, reducing the likelihood of liquid or other substances entering.

[0135] As shown in the second embodiment (Figures 5 and 6), the at least one contact oxidation region 23A may include a plurality of contact oxidation regions 23A (23Ad and / or 23Ae) ​​that are separated from each other in a cross section parallel to the D3 direction (for example, a D1D3 cross section). In the D1D3 cross section, the plurality of contact oxidation regions 23A may each have a length Hd or He in the D3 direction that is shorter than the length Ld or Le in the D1 direction (an example of a first direction) that intersects the D3 direction. When a plurality of contact oxidation regions 23A (a part or all of the at least one contact oxidation region 23A) are separated from each other, the plurality of contact oxidation regions 23A may be separated from each other in the D1 direction, such as the main surface oxidation region 23Ad (or, from another viewpoint, they may not overlap when viewed in the D3 direction), or they may be separated from each other in the D3 direction, such as the end oxidation region 23Ae (or, from another viewpoint, they may not overlap when viewed in the D1 direction).

[0136] In this case, as can be understood, for example, from a comparison with the first embodiment, since multiple contact oxidation regions 23A are discretely arranged, the length (proportion) of contact between the contact oxidation region 23A and the insulator 15 can be adjusted. In the first embodiment as well, the length of one contact oxidation region 23A can be adjusted, but in this case, unlike the second embodiment, the contact position is concentrated in one place. Therefore, for example, in the second embodiment, it is easier to obtain the above-mentioned effects to a desired extent within a desired range. Also, for example, when flat main surface oxidation regions 23Ad are arranged in the D1 direction, it is easier to shift the area of ​​the oxidation region 23 towards the insulator 15 side in the D1D3 cross section. As a result, for example, it is easier to shorten the length of contact between the oxidation region 23 of the base electrode 17 and the external electrode 5. Also, for example, when flat end oxidation regions 23Ae are arranged in the D3 direction, for example, the volume expansion of the end oxidation region 23Ae can form irregularities on the side surface of the end E1. These irregularities contribute, for example, to reducing the likelihood of delamination by engaging the end portion E1 and the insulator 15 in the D3 direction.

[0137] In a cross section parallel to the D3 direction (D1D3 cross section), the total length Ld in the D1 direction where at least one contact oxidation region 23A (main surface oxidation region 23Ad) is in contact with the insulator 15 may be 5% or more and 30% or less of the length L0 of the base electrode 17 in the D1 direction.

[0138] Furthermore, in a cross section parallel to the D3 direction (D1D3 cross section), when the dimension in the D3 direction is referred to as thickness, the above-mentioned at least one contact oxidation region 23A may include a contact oxidation region 23A having a thickness of 5% to 30% of the thickness H0 of the base electrode 17.

[0139] In these cases, for example, the effects described above are achieved to a certain extent. Furthermore, the likelihood of problems arising from excessive oxidation of the base electrode 17 (for example, an increase in the contact area between the oxidized region 23 and the external electrode 5) is reduced.

[0140] The base electrode 17 does not have to be in contact with the internal electrode 13. From another viewpoint, the external electrode 5 may be in contact with the internal electrode 13 without going through the base electrode 17.

[0141] In this case, for example, the likelihood of an increase in the equivalent series resistance of the capacitor 1 due to the oxidation region 23 of the base electrode 17 is reduced. That is, it is easier to maintain the electrical characteristics of the capacitor 1 while obtaining the effects of the oxidation region 23.

[0142] 1...Capacitor (multilayer electronic component), 5...External electrode, 7...Laminate, 9...Cover, 11...Dielectric, 13...Internal electrode, 15...Insulator, 17...Base electrode, 23...Oxidation region (of the base electrode), 23A...Contact oxidation region.

Claims

1. A laminated electronic component comprising: a laminate having dielectrics and internal electrodes alternately overlapping in the stacking direction; a cover overlapping the laminate in the stacking direction; and an external electrode overlapping the side of the cover opposite to the laminate, wherein the cover comprises an insulator and a base electrode overlapping the insulator on the side opposite to the laminate in the stacking direction, and the side opposite to the insulator in the stacking direction is in contact with the external electrode, wherein the base electrode has one or more oxidation regions, and the one or more oxidation regions include at least one contact oxidation region in contact with the insulator.

2. The stacked electronic component according to claim 1, wherein a predetermined end portion that constitutes a part of the outer edge of the base electrode and is located on the central side of the stacked electronic component in a first direction intersecting the stacking direction is recessed toward the stacked material relative to the insulator, and the at least one contact oxidation region includes a contact oxidation region located at the predetermined end portion that is in contact with the insulator in the first direction.

3. The laminated electronic component according to claim 1 or 2, wherein, in a cross-section parallel to the lamination direction, the total length over which the oxidized region of the base electrode is in contact with the external electrode is shorter than the total length over which the oxidized region of the base electrode is in contact with the insulator.

4. The stacked electronic component according to any one of claims 1 to 3, wherein, in a cross section parallel to the stacking direction, the ratio of the total area of ​​the oxidation region of the base electrode to the area of ​​the base electrode is greater than the ratio of the total area of ​​the oxidation region of the internal electrode to the area of ​​the internal electrode.

5. In a cross section parallel to the stacking direction, the ratio of the total area of ​​the oxidation region of the base electrode to the area of ​​the base electrode is smaller than the ratio of the total area of ​​the oxidation region of the internal electrode to the area of ​​the internal electrode, according to any one of claims 1 to 3.

6. The stacked electronic component according to any one of claims 1 to 5, wherein the at least one contact oxidation region includes a plurality of contact oxidation regions that are spaced apart from each other and whose length in the stacking direction is shorter than the length in the direction intersecting the stacking direction, in a cross section parallel to the stacking direction.

7. In a cross section parallel to the stacking direction, when the direction intersecting the stacking direction is referred to as the first direction, the total length in the first direction in which at least one contact oxidation region is in contact with the insulator is 5% or more and 30% or less of the length of the base electrode in the first direction, according to any one of claims 1 to 6.

8. In a cross section parallel to the stacking direction, where the dimension in the stacking direction is referred to as thickness, the at least one contact oxidation region includes a contact oxidation region having a thickness of 5% to 30% of the thickness of the underlying electrode, according to any one of claims 1 to 7.

9. The laminated electronic component according to any one of claims 1 to 8, wherein the base electrode is not in contact with the internal electrode.

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