Electronic components

Abstract

To provide an electronic component that can be easily manufactured and has excellent reliability.SOLUTION: An electronic component has an element body 4 with a plurality of side surfaces 5a to 5d along the circumferential direction. The element body 4 has insulating layers 16a to 16d that continuously cover the plurality of side surfaces 5a to 5d along the circumferential direction, and the properties (porosity, dielectric grain shape, etc.) of the insulating layers 16a to 16d are substantially the same along the circumferential direction.SELECTED DRAWING: Figure 2Aa

Description

Technical Field

[0001] The present invention relates to an electronic component such as a multilayer ceramic capacitor, for example.

Background Art

[0002] For example, in an electronic component such as the multilayer ceramic capacitor disclosed in Patent Document 1, a side gap insulating layer made of a dielectric material is formed on a side surface of an element body where side portions of internal electrode layers are exposed, in order to increase the area of the internal electrode layers while achieving size reduction of the electronic component.

[0003] However, in conventional multilayer ceramic capacitors, the side gap insulating layer is formed, for example, by a coating method and formed by firing simultaneously with the element body. Therefore, conventional multilayer ceramic capacitors have a problem that it is difficult to control the formation range of the side gap insulating layer.

[0004] For example, in order to effectively protect the side surface of the element body where the side portions of the internal electrode layers are exposed, if the side edge of the side gap insulating layer is formed to cover up to the end face of the element body, the exposed end portions of the internal electrode layers exposed on the end face of the element body may also be covered. In such a case, there is a risk that the connection between the exposed end portions of the internal electrode layers exposed at the end of the element body and the terminal electrode formed on the end face of the element body becomes incomplete.

[0005] In particular, as the size of the element body decreases, it tends to become more difficult to form the insulating layer only on the side surfaces of the element body without covering the exposed end portions of the internal electrode layers exposed on the end face of the element body. Additionally, when the insulating layer is formed only on the side surfaces of the element body, there is also a problem that the insulating layer is easily peeled off from the element body at the corners between adjacent side surfaces. If the insulating layer peels off from the side surface of the element body, problems such as short-circuit defects may occur.

Prior Art Literature

Patent Literature

[0006] [Patent Document 1] Japanese Patent Publication No. 62-237714 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above circumstances, and its purpose is to provide an electronic component that can be easily manufactured and is highly reliable. [Means for solving the problem]

[0008] To achieve the above objective, the electronic component according to the present invention is An electronic component having an element body with multiple sides along the circumferential direction, The element body has an insulating layer that continuously covers multiple sides along the circumferential direction. The insulating layer is characterized in that its properties are substantially identical along the circumferential direction. Note that "substantially identical (or the same)" means that variations of ±5% or less are acceptable.

[0009] This configuration prevents the boundary between the insulating layer and the element body from being exposed to the outside air, preventing moisture from entering the internal electrodes from the boundary, thus improving reliability. The properties of the insulating layer are substantially uniform along the circumferential direction. Therefore, even with small-sized electronic components, the insulating layer is not prone to peeling from the corners of the element body, reducing the risk of short-circuit failures. Furthermore, because the properties of the insulating layer are substantially the same along the circumferential direction, stress can be uniformly distributed and peeling can be prevented.

[0010] Furthermore, since the side gap insulating layer can be formed by the rolling transfer method, unlike the coating method, the insulating layer is not formed in unnecessary areas. Therefore, the insulating layer is not substantially formed on the end face of the element body where the terminal electrodes are formed and connect to the internal electrode layer. As a result, even if the element body is miniaturized, the reliability of the connection between the terminal electrodes and the internal electrodes is also improved.

[0011] The insulating layer in the electronic component of the present invention is an insulating layer that continuously covers multiple sides along the circumferential direction, and therefore can be formed with substantially consistent quality even in areas other than the side gap insulating layer. In particular, the insulating layer has consistent characteristics even at the corners of the side surfaces of the element body. Furthermore, unlike the edges of insulating layers formed by coating methods, in the electronic component of the present invention, it is not necessary to position the edges of the insulating layer near the corners of the side surfaces of the element body.

[0012] In conventional electronic components, the edges of the insulating layer formed by the coating method must be positioned near the corners of the side surface of the element body so as not to reduce the area of ​​the end surface of the element body that serves as the connection end surface with the terminal electrode. In contrast, in the electronic component of the present invention, since the insulating layer can be formed by the rolling transfer method, an insulating layer with consistent characteristics is formed even near the corners of the side surface of the element body, compared to other areas. Unlike conventional designs, thin insulating layer edges are not formed near the corners. Therefore, moisture intrusion can be effectively prevented, improving the moisture resistance and reliability of the electronic component, and the insulating layer is not prone to peeling off from the corners of the element body, reducing the risk of short-circuit failures.

[0013] Preferably, the pore ratio at a predetermined depth from the surface of the insulating layer at the corner of the element body is substantially the same as the pore ratio at a predetermined depth from the surface of the insulating layer at at least one of the two sides of the element body connected to the corner.

[0014] In the electronic component of the present invention, an insulating layer with substantially constant characteristics (for example, substantially constant pore ratio) is formed even at the corners of the element body. Therefore, moisture intrusion from the corners of the element body can be effectively prevented, improving the moisture resistance and reliability of the electronic component, and the insulating layer is not prone to peeling off from the corners of the element body, thus reducing the risk of short-circuit failures.

[0015] Preferably, the pore ratio at a predetermined depth from the surface of the insulating layer is substantially the same along the circumferential direction. By making the characteristics (pore ratio) of the insulating layer substantially the same along the circumferential direction across multiple sides of the element body, the insulating layer is less likely to peel off from the corners of the element body, and the risk of short-circuit failures is reduced.

[0016] Preferably, the insulating layer contains ceramic particles, and the particle size of the ceramic particles at a predetermined depth from the surface of the insulating layer is substantially the same along the circumferential direction. By making the characteristics (pore ratio) of the insulating layer substantially the same along the circumferential direction across multiple sides of the element body, the insulating layer is less likely to peel off from the corners of the element body, and the risk of short-circuit failures is reduced.

[0017] The insulating layer may be made of a dielectric material having substantially the same composition as, or a different composition from, the dielectric layer of the element body. If the insulating layer has substantially the same composition as the dielectric layer, the element body and the insulating layer can be fired together as a single unit. Preferably, the insulating layer has a composition that contains a higher amount of components that improve sinterability than the dielectric layer of the element body.

[0018] The element body may have a laminated structure in which the ceramic layer and the internal electrode layer are stacked. Furthermore, terminal electrodes connected to the exposed ends of the internal electrode layer may be formed on the end faces of the element body that intersect the side surfaces. Preferably, the edges of the terminal electrodes cover the ends of the insulating layer. This configuration makes it even more difficult for moisture to penetrate into the inside of the element body, improving the moisture resistance of the electronic component and also improving its reliability.

[0019] Preferably, the insulating layer covers all sides of the element body that are continuous along the circumferential direction. This configuration further effectively prevents the insulating layer from peeling off the element body. In addition, since the entry paths to the interface between the insulating layer and the element body can be blocked along the entire circumference of the side surfaces of the element body, the moisture resistance and reliability of the electronic component are further improved.

[0020] Note that, even if the insulating layer does not completely cover all continuous side surfaces along the circumferential direction of the element body, a gap may be provided in the insulating layer on one of all side surfaces of the element body. That is, on one of all the side surfaces of the element body, edge edges of the insulating layer are positioned along a direction perpendicular to the circumferential direction near the center of the side surface far from corners of the element body, and a part of the side surface of the element body may be exposed from a gap between the edge edges.

[0021] Preferably, the composition of the insulating layer is substantially uniform along the circumferential direction. When the composition of the insulating layer is uniform, moisture resistance is also uniform along the circumferential direction, origins that lower moisture resistance are reduced, and the reliability of the electronic component is improved. Note that forming the insulating layer by a rolling transfer method facilitates forming the insulating layer having a substantially uniform composition along the circumferential direction.

[0022] Preferably, the thickness of the insulating layer is 3 μm to 40 μm. Further preferably, the thickness of the insulating layer is substantially uniform along the circumferential direction. By making the thickness of the insulating layer uniform, origins that lower moisture resistance are reduced, the moisture resistance of the electronic component is improved, and reliability is also improved. Since the insulating layer can be formed by a rolling transfer method, the thickness of the insulating layer tends to be substantially uniform along the circumferential direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. [Figure 2A] FIG. 2A is a cross-sectional view taken along line IIA-IIA shown in FIG. 1. [Figure 2Aa] FIG. 2Aa is a partially enlarged view of the cross-sectional view shown in FIG. 2A. [Figure 2Ab] FIG. 2Ab is a modification of the partially enlarged view shown in FIG. 2Aa. [Figure 2B] FIG. 2B is a cross-sectional view taken along line IIB-IIB shown in FIG. 1. [Figure 3A] FIG. 3A is a cross-sectional view of a multilayer ceramic capacitor according to another embodiment of the present invention. [Figure 3B] Figure 3B is a cross-sectional view of a multilayer ceramic capacitor according to yet another embodiment of the present invention. [Figure 3C] Figure 3C is a cross-sectional view of a multilayer ceramic capacitor according to yet another embodiment of the present invention. [Figure 4A] Figure 4A is a schematic cross-sectional view parallel to the X and Z axes, showing the lamination process of the green sheet in the manufacturing process of the multilayer ceramic capacitor shown in Figure 1. [Figure 4B] Figure 4B is a schematic cross-sectional view parallel to the Y and Z axes, showing the lamination process of the green sheet shown in Figure 4A. [Figure 5A] Figure 5A is a schematic perspective view of the laminate after the cutting process following the lamination process, as shown in Figures 4A and 4B. [Figure 5B] Figure 5B is a schematic perspective view of a laminated body after the cutting process in the manufacturing process of a multilayer ceramic capacitor according to another embodiment of the present invention. [Figure 6A] Figure 6A is a schematic perspective view showing the manufacturing process of the multilayer ceramic capacitor of the present invention. [Figure 6B] Figure 6B is a schematic perspective view showing the continuation of the process shown in Figure 6A. [Figure 6C] Figure 6C is a schematic perspective view showing the continuation of the process shown in Figure 6B. [Figure 6D] Figure 6D is a schematic perspective view showing the continuation of the process shown in Figure 6C. [Figure 6E] Figure 6E is a schematic perspective view showing the continuation of the process shown in Figure 6D. [Figure 6F] Figure 6F is a schematic perspective view showing the continuation of the process shown in Figure 6E. [Figure 6G] Figure 6G is a schematic perspective view showing the continuation of the process shown in Figure 6F. [Figure 6H] Figure 6H is a schematic perspective view of the laminate after it has been separated from the sheet following the process shown in Figure 6G. [Figure 7A] Figure 7A is a schematic perspective view showing the manufacturing process of a multilayer ceramic capacitor according to a modified example of the present invention. [Figure 7B]Figure 7B is a schematic perspective view showing the continuation of the process shown in Figure 7A. [Figure 7C] Figure 7C is a schematic perspective view showing the continuation of the process shown in Figure 7B. [Figure 7D] Figure 7D is a schematic perspective view showing the continuation of the process shown in Figure 7C. [Figure 7E] Figure 7E is a schematic perspective view showing the continuation of the process shown in Figure 7D. [Figure 7F] Figure 7F is a schematic perspective view showing the continuation of the process shown in Figure 7E. [Figure 8A] Figure 8A is a schematic perspective view showing the manufacturing process of a multilayer ceramic capacitor according to another modification of the present invention. [Figure 8B] Figure 8B is a schematic perspective view showing the continuation of the process shown in Figure 8A. [Figure 8C] Figure 8C is a schematic perspective view showing the continuation of the process shown in Figure 8B. [Figure 8D] Figure 8D is a schematic perspective view showing the continuation of the process shown in Figure 8C. [Figure 8E] Figure 8E is a schematic perspective view showing the continuation of the process shown in Figure 8D. [Figure 8F] Figure 8F is a schematic perspective view showing the continuation of the process shown in Figure 8E. [Figure 8G] Figure 8G is a schematic perspective view of the laminate after it has been separated from the sheet following the process shown in Figure 8F. [Figure 9A] Figure 9A is a schematic perspective view showing the process of cleaning the surface of the laminate. [Figure 9B] Figure 9B is a schematic perspective view showing the continuation of the process shown in Figure 9A. [Modes for carrying out the invention]

[0024] The present invention will be described below based on the embodiments shown in the drawings.

[0025] First Embodiment (Overall configuration of a multilayer ceramic capacitor) As one embodiment of the electronic component according to this embodiment, the overall configuration of a multilayer ceramic capacitor will be described.

[0026] As shown in Figure 1, the multilayer ceramic capacitor 2 according to this embodiment has a laminate (element body) 4 made of a ceramic sintered body, a first terminal electrode 6, and a second terminal electrode 8.

[0027] As shown in Figure 1, the laminate 4 has an inner dielectric layer (ceramic layer) 10 and an inner electrode layer 12 that are substantially parallel to a plane containing the X and Y axes, with the inner electrode layers 12 alternately stacked between the inner dielectric layers 10 along the Z-axis. Here, "substantially parallel" means that most of the parts are parallel, but there may be some parts that are not parallel, and the inner electrode layers 12 and inner dielectric layers 10 may have some irregularities or be tilted. Note that in the figure, the X, Y, and Z axes are approximately perpendicular to each other.

[0028] The inner dielectric layer 10 and the inner electrode layer 12 are alternately stacked in the inner region 13. The laminate 4 also has outer regions 11 on both end faces in the stacking direction Z (Z-axis). The outer region 11 is formed by stacking one or more outer dielectric layers. In the following, the "inner dielectric layer 10" and the "outer dielectric layer" may be collectively referred to as the "dielectric layer (ceramic layer)".

[0029] The dielectric layers constituting the inner dielectric layer 10 and the outer region 11 may be the same or different, and are not particularly limited. For example, they may be composed mainly of a perovskite dielectric material such as ABO3 or an alkali niobate ceramic. In ABO3, A is at least one such as Ca, Ba, or Sr, and B is at least one such as Ti or Zr. The molar ratio of A / B is not particularly limited and is between 0.980 and 1.020.

[0030] The number of layers of the inner dielectric layer 10 and the outer dielectric layer can be determined appropriately depending on the application, etc. The thickness td of the inner dielectric layer 10 shown in Figure 2A is, for example, 0.1 μ The thickness is approximately 40 μm. The ratio of the thickness td of the inner dielectric layer 10 to the thickness te of the inner electrode layer 12 is not particularly limited, but it is preferable that td / te is 2 to 0.5. Also, the ratio of the thickness t0 of the outer region 11 (see Figure 1) to the height H0 of the element 3 (see Figure 2A) is not particularly limited, but it is preferable that t0 / H0 is 0.01 to 0.1.

[0031] The shape and size of element 3 can be determined appropriately according to the purpose and application, but it is preferable that the width W0 in the X-axis direction is 0.1 mm to 3.2 mm, the length L0 in the Y-axis direction is 0.2 mm to 3.2 mm, and the height H0 in the Z-axis direction is 0.1 mm to 3.2 mm. It is also preferable that the multilayer ceramic capacitor 2, which includes the first terminal electrode 6 and the second terminal electrode 8 in element 3, is within this range.

[0032] As shown in Figure 1, one of the alternately stacked internal electrode layers 12 has a lead-out portion 12α that is electrically connected to the inside of the first terminal electrode 6 formed on one end face 5e in the Y-axis direction of the laminate 4. The other alternately stacked internal electrode layer 12 has a lead-out portion 12β that is electrically connected to the inside of the second terminal electrode 8 formed on the other end face 5f in the Y-axis direction of the laminate 4.

[0033] The interior region 13 has a capacitance region 14 and lead regions 15A and 15B. The capacitance region 14 is the region in which the internal electrode layers 12 are stacked along the stacking direction, sandwiching the inner dielectric layer 10. The lead region 15A is the region located between the lead portions 12α of the internal electrode layers 12 that are connected to the terminal electrodes 6. The lead region 15B is the region located between the lead portions 12β of the internal electrode layers 12 that are connected to the terminal electrodes 8.

[0034] The conductive material contained in the internal electrode layer 12 is not particularly limited, and metals such as Ni, Cu, Ag, Pd, Al, Pt, or alloys thereof can be used. As the Ni alloy, an alloy of Ni with one or more elements selected from Mn, Cr, Co, and Al is preferred, and the Ni content in the alloy is preferably 95% by weight or more. In addition, various trace components such as P may be contained in the Ni or Ni alloy at a concentration of about 0.1% by weight or less. The internal electrode layer 12 may be formed using commercially available electrode paste, and the thickness of the internal electrode layer 12 can be appropriately determined according to the application.

[0035] In this embodiment, as shown in Figure 2A, the four sides 5a to 5d of the laminate 4, which serves as the element body, are continuously covered by insulating layers 16a to 16d that are continuous along the circumferential direction. That is, insulating layers 16a to 16d are continuously formed along the circumferential direction on the sides 5a and 5c located on both sides along the Z-axis of the laminate 4, and on the sides 5b and 5d located on both sides along the X-axis of the laminate 4, so as to cover the respective sides 5a to 5d. In this specification, the direction around the Y-axis of the laminate, including the sides 5a to 5d, may be referred to as the circumferential direction or outer peripheral direction.

[0036] In this embodiment, the configurations of insulating layers 16a to 16d are substantially the same. Therefore, for the sake of simplicity, unless otherwise specified, insulating layers 16a and 16b will be described below, and the descriptions of insulating layers 16c and 16d will be omitted.

[0037] As shown in Figure 2Aa, the insulating layer 16a formed on the upper side surface 5a of the laminate 4 along the Z-axis has a substantially uniform thickness tz in the Z-axis direction. Here, thickness tz refers to the shortest distance from the outer circumferential surface 16a1 of the insulating layer 16a, which is substantially parallel to the XY plane, to the side surface 5a of the laminate 4. In addition, the insulating layer 16b formed on one side surface 5b of the laminate 4 along the X-axis has a substantially uniform thickness tx in the X-axis direction. Here, thickness tx refers to the shortest distance from the outer circumferential surface 16b1 of the insulating layer 16b, which is substantially parallel to the YZ plane, to the side surface 5b of the laminate 4. In this embodiment, thickness tx and thickness tz are substantially the same.

[0038] Furthermore, in this embodiment, it is preferable that a radius of curvature R portion is formed at the corner 17 where side surfaces 5a and 5b intersect, and the thickness tp of the insulating layer 16p at the corner 17 is substantially the same as at least one of the thickness tx and thickness tz, preferably both. In this specification, insulating layers 16a to 16d may also be used to include the insulating layer 16p at the corner 17.

[0039] Here, the corner 17 refers to the corner where the sides 5a and 5b of the laminate 4 intersect, when the interface between the laminate 4 and the insulating layers 16a and 16b is clearly defined. In other words, the corner 17 is sandwiched between the sides 5a and 5b of the laminate 4. If the interface between the laminate 4 and the insulating layers 16a and 16b is not clearly defined, it refers to the corner where the outer circumferential surfaces 16a1 of the insulating layer 16a and 16b1 of the insulating layer 16b intersect.

[0040] For example, a corner is defined as the region centered on a line P1 on the outer surface of the insulating layer that is closest to the intersection line P0 of the XY plane formed by the extended surface 16a1 of the outer surface 16a of the insulating layer 16a and the YZ plane formed by the extended line of the outer surface 16b1 of the insulating layer 16b. Furthermore, the thickness tp of the insulating layer at the corner 17 is defined as the shortest distance from P1 to the laminate 4.

[0041] Even if the insulating layers 16a to 16d and the dielectric layers 10 and 11 are made of substantially the same material, the interface between the X-axis side edge of the internal electrode layer 12 and the insulating layer 16b can be clearly measured from a cross-sectional photograph of the laminate 4. Therefore, the thickness tx of the insulating layer 16b can be measured.

[0042] However, when the insulating layers 16a to 16d and the dielectric layers 10 and 11 are made of substantially the same material, it is difficult to clearly measure the interface between the dielectric layers 10 and 11 and the insulating layer 16b from cross-sectional photographs of the laminate 4. Therefore, the thickness tz of the insulating layer 16a and the thickness tp of the insulating layer 16p may actually be difficult to measure.

[0043] In this embodiment, the predetermined depth d is set to half of the minimum value within a preferred range for the thickness tx of the insulating layer 16b. By measuring the pore ratio (void ratio) at the predetermined depth d in the insulating layers 16a to 16b, the degree of uniformity of the characteristics of the insulating layer in the circumferential direction along the insulating layers 16a to 16b can be confirmed. The predetermined depth d is determined as a constant value within the range of, for example, 1.5 to 20 μm.

[0044] For example, in this embodiment, the pore ratio at a predetermined depth d from the surface P1 of the insulating layer 16p at the corner 17 is substantially the same as the pore ratio at a predetermined depth d from the surface of the insulating layer 16a, 16b at at least one of the two sides 5a, 5b of the laminate 4 connected to the corner 17.

[0045] Furthermore, the statement that "the pore ratio of the insulating layer 16p at a predetermined depth d at the corner 17 is substantially the same as the pore ratio of the insulating layers 16a and 16b at a predetermined depth from the surface of at least one of the two sides 5a and 5b of the laminate 4 connected to the corner 17" can be determined, for example, as follows.

[0046] At the corner 17, with the insulating layer 16p at position P1 and a predetermined depth d at position O as the center, cross-sectional images were taken at 10 or more points in different cross-sections along the Y-axis for a unit area S. The pore ratio per unit area S was determined, and the average value was taken as the pore ratio. In calculating the pore ratio, an SEM image of the cross-section was acquired, and for example, within a unit cross-sectional area S = 5 × 3.5 μm, the total area of ​​black void images where dielectric particles are not observed and voids can be automatically calculated, and the value obtained by dividing by the unit area can be expressed as a percentage.

[0047] Similarly, the pore ratio of the insulating layer 16a at the central position along the X-axis of the laminate 4 can be determined in the same manner as described above. Similarly, the pore ratio of the insulating layer 16b at the central position along the Z-axis of the laminate 4 can be determined.

[0048] In this embodiment, if the difference between the pore ratio of the insulating layer 16p and the pore ratio of the insulating layer 16a at the corner 17 is ±5% or less, they are judged to be substantially the same. Similarly, the difference between the pore ratio of the insulating layer 16p and the pore ratio of the insulating layer 16b at the corner 17 can be judged in the same way.

[0049] In this embodiment, the pore ratio of the insulating layer 16p at the corner 17 is preferably in the range of 0 to 10%. Furthermore, the pore ratio of the insulating layer 16p at the corner 17 is preferably about 0 to 5% smaller than the pore ratio measured at a predetermined position of the dielectric layer 10 (for example, an intermediate position in the X-axis direction).

[0050] In this embodiment, the insulating layer 16a and the insulating layer 16b are smoothly and uniformly connected in a continuous manner at the corner 17, and there is substantially no gap from the insulating layer 16a to the insulating layer 16b, and there is no interface between the insulating layer 16a and the insulating layer 16b.

[0051] In this embodiment, the pore ratio at a predetermined depth d from the surface in each insulating layer 16a to 16d can also be determined in the same manner as described above, and all of these pore ratios can be made substantially the same. Similarly, the particle size (average particle size within a unit area S) of dielectric particles at a predetermined depth d from the surface in each insulating layer 16a to 16d and 16p can also be determined, and in this embodiment, these particle sizes are also substantially the same.

[0052] In this embodiment, the particle size (average) of the dielectric particles in the insulating layer 16p at the corner 17 is preferably in the range of 150 to 350 μm.

[0053] In this embodiment, the thickness of the insulating layers 16a to 16d and 16p is preferably in the range of 3 μm to 40 μm, and can be made uniform in thickness. This reduces the influence of the thermal expansion coefficient of the insulating layer and can suppress structural defects caused by the difference in thermal expansion coefficients between the laminate 4 and the insulating layer. In addition, in this embodiment, the insulating layers 16b and 16d act as side gap insulating layers, and the exposed ends of the internal electrode layer 12 in the X-axis direction can be covered with the insulating layers 16b and 16d, providing sufficient protection. Furthermore, in this embodiment, the variation in the thickness of each insulating layer 16a to 16d and 16p is small.

[0054] In this embodiment, the outer surface of the insulating layer 16p at the corner 17 does not have to be rounded (R-shaped). For example, as shown in Figure 2Ab, if the corner 17 of the laminate 4 is chamfered (C-chamfered), the outer surface of the insulating layer 16p becomes planar along the C-plane of the laminate 4. In this case, P1 will be located on the outer surface of the insulating layer 16p, which is planar along the C-plane. In other embodiments of this model, the corner 17 may not have a rounded (R-shaped) portion or a chamfered (C-chamfered) portion, in which case P0 and P1 will be very close together.

[0055] As shown in Figure 1, it is preferable that the insulating layers 16a and 16c (and insulating layers 16b and 16d, which are not shown, are similar / hereinafter omitted) do not substantially cover the end faces 5e and 5f located at both ends of the laminate 4 in the Y-axis direction. That is, it is preferable that the insulating layers 16a and 16c do not cover the connection ends of the lead portions 12α or 12β of the internal electrode layer 12 that are exposed on the end faces 5e and 5f located at both ends of the laminate 4 in the Y-axis direction. This is because terminal electrodes 6 and 8 need to be formed on the outer surfaces 5e and 5f located at both ends of the laminate 4 in the Y-axis direction and connected to the lead portions 12α or 12β of the internal electrode layer 12.

[0056] The insulating layers 16a to 16d (including 16p / hereinafter the same) of this embodiment are made of a dielectric material having substantially the same or different composition as the dielectric layers 10 and 11 of the element body 4. A composition substantially the same as the dielectric layers 10 and 11 of the element body 4 means, for example, that the main dielectric component of the dielectric layers 10 and 11 of the element body 4 is the same as the main dielectric component of the insulating layers 16a to 16d. For example, the main dielectric component of the insulating layers 16a to 16d may be a perovskite dielectric material such as ABO3 or an alkali niobate ceramic.

[0057] Preferably, the insulating layers 16a to 16d are composed of a higher content of components that improve sinterability than the dielectric layers 10 and 11 of the device body 4.

[0058] The composition of the dielectric layers 10 and 11 is determined from the viewpoint of improving properties necessary for electronic components, such as dielectric constant, while enabling simultaneous firing with the internal electrode layer 12. The composition of the insulating layers 16a to 16d is determined such that, for example, simultaneous firing with the internal electrode layer 12 is possible, without causing compositional discrepancies with the dielectric layers 10 and 11, and that the composition is superior to that of the dielectric layers 10 and 11 in terms of sinterability. From this viewpoint, examples of preferred components that are present in greater quantities in the insulating layers 16a to 16d than in the dielectric layers 10 and 11 include boron, lithium, silicon (Si), manganese, and magnesium.

[0059] For example, if the insulating layers 16a to 16d contain a higher amount of components such as boron (approximately 0.5 to 5.0 mol%) compared to the dielectric layers 10 and 11, the insulating layers 16a to 16d will sinter at a lower temperature than the dielectric layers 10 and 11, the sintering density will be improved, and the effect of preventing moisture intrusion will be enhanced.

[0060] Furthermore, in this embodiment, since the main component of the insulating layers 16a to 16d is a dielectric, sintering occurs at low temperatures, the sintering density is improved, and the effect of preventing moisture intrusion is greatly enhanced.

[0061] In this embodiment, as shown in Figure 1, both ends of the terminal electrodes 6 and 8 in the Z-axis direction are formed to cover both ends of the insulating layers 16a and 16c in the Y-axis direction. Also, as shown in Figure 2B, both ends of the terminal electrodes 6 and 8 in the X-axis direction are formed to cover both ends of the insulating layers 16b and 16d in the Y-axis direction.

[0062] With this configuration, the terminal electrodes 6 and 8 at the end faces 5e and 5f of the laminate 4 can completely cover the edges of the interface between the insulating layers 16a to 16d and the laminate 4, thereby improving durability and moisture resistance.

[0063] The thickness of terminal electrodes 6 and 8 can be determined appropriately depending on the application.

[0064] The terminal electrodes 6 and 8 of this embodiment consist of a baked layer (not shown) in contact with the element 3 and a plating layer (not shown) formed on top of it. Cu metal, Ni metal, etc. are used as the baked layer. This baked layer is formed to cover the end face 5e and a portion of the insulating layers 16a, 16b, 16c, and 16d. The plating layer can be Ni plating, Cu plating, Sn plating, etc. In this embodiment, the terminal structure has a Ni plating layer formed on top of the Cu baked layer, and a Sn plating layer formed on top of the Ni plating layer.

[0065] (Manufacturing method for multilayer ceramic capacitors) Next, a method for manufacturing a multilayer ceramic capacitor 2 as one embodiment of the present invention will be described in detail.

[0066] (Laminate manufacturing process) First, the manufacturing process of the laminated body 4, which will form the main body of the element, will be explained. An inner green sheet 10a, shown in Figure 4A, which will constitute the inner dielectric layer 10 shown in Figure 1 after firing, and an outer green sheet 11a, also shown in Figure 4A, which will constitute the outer region 11 shown in Figure 1, are prepared.

[0067] To form these green sheets 10a and 11a, first, an inner green sheet paste and an outer green sheet paste are prepared, respectively. The inner green sheet paste and the outer green sheet paste are usually composed of an organic solvent-based paste or a water-based paste obtained by kneading ceramic powder and an organic vehicle.

[0068] As raw materials for the ceramic powder, various compounds that form complex oxides or oxides, such as carbonates, nitrates, hydroxides, and organometallic compounds, can be appropriately selected and mixed. In this embodiment, the raw materials for the ceramic powder are used as powder with an average particle size of 0.45 μm or less, preferably about 0.05 to 0.3 μm. In order to make the inner green sheet extremely thin, it is desirable to use powder that is finer than the thickness of the green sheet.

[0069] Next, the internal electrode pattern layer 12a shown in Figure 4A, which will constitute the internal electrode layer 12 shown in Figure 1 after firing, is formed. For this purpose, an internal electrode layer paste is prepared. The internal electrode layer paste is prepared by kneading the conductive material consisting of the various conductive metals and alloys described above with the organic vehicle described above. The metal paste (terminal electrode paste) which will constitute the terminal electrodes 6 and 8 shown in Figure 1 after firing can be prepared in the same manner as the internal electrode layer paste described above.

[0070] Using the paste for the inner green sheet and the paste for the inner electrode layer prepared as described above, the inner green sheet 10a and the inner electrode pattern layer 12a are alternately stacked as shown in Figures 4A and 4B to produce an inner laminate. After producing the inner laminate, the outer green sheet 11a is formed using the paste for the outer green sheet, and the green laminate is obtained by applying pressure in the stacking direction.

[0071] In addition to the above, a green laminate can also be manufactured by alternately stacking a predetermined number of inner green sheets 10a and internal electrode pattern layers 12a directly onto an outer green sheet 11a, and then applying pressure in the stacking direction to obtain a green laminate.

[0072] Next, the green laminate is cut along the C1 and C2 cross-sections in Figures 4A and 4B to obtain green chips 4a. C1 is a cross-section parallel to the Y-Z axis plane, and C2 is a cross-section parallel to the Z-X axis plane.

[0073] As shown in Figure 4B, the C2 cut surfaces adjacent to the C2 cut surface that cuts the internal electrode pattern layer 12a in the nth layer cut through the gaps in the internal electrode pattern layer 12a. Furthermore, the C2 cut surface that cuts the internal electrode pattern layer 12a in the nth layer cuts through the gaps in the internal electrode pattern layer 12a in the (n+1)th layer.

[0074] By using this cutting method, the green chip 4a shown in Figure 5A is obtained such that the nth internal electrode pattern layer 12a of the green chip 4a is exposed on one end face 5e in the Y-axis direction of the green chip 4a, but not on the other end face 5f. Conversely, the (n+1)th internal electrode pattern layer 12a of the green chip 4a is not exposed on one bottom face 5e in the Y-axis direction of the green chip 4a, but is exposed on the other bottom face 5f.

[0075] Furthermore, in the C1 cross-section of the green chip 4a shown in Figure 4A, that is, the sides 5b and 5d of the green chip 4a facing each other in the X-axis direction as shown in Figure 5A, the internal electrode pattern layer 12a is exposed in all layers. The method for forming the internal electrode pattern layer 12a is not particularly limited and may be formed by printing, transfer, or thin film formation methods such as vapor deposition or sputtering.

[0076] The green chip 4a is solidified by solidification drying, which removes the plasticizer. After drying, the green chip 4a is subjected to a debindering process, a firing process, and an annealing process as needed to obtain a laminate 4 before the insulating layers 16a to 16d shown in Figure 2A are formed. Furthermore, the terminal electrodes 6 and 8 shown in Figure 1 are not yet formed on this laminate 4. The perspective view of the laminate 4 before the insulating layers and terminal electrodes are formed is the same as the perspective view of the green chip 4a, as shown in Figure 5A.

[0077] In this embodiment, the debindering step may be performed with a holding temperature of, for example, 200°C to 400°C. The firing step may be performed in a reducing atmosphere, for example, and the annealing step may be performed in a neutral or weakly oxidizing atmosphere. Other firing or annealing conditions may include, for example, a holding temperature of 1000°C to 1300°C for firing and a holding temperature of 500°C to 1100°C for annealing. The debindering step, firing step, and annealing step may be performed consecutively or independently.

[0078] In the embodiments described above, the green laminate shown in Figures 4A and 4B is fragmented into green chips 4a, and then the green chips 4a are fired to form the laminate 4. However, the green laminate shown in Figures 4A and 4B may be fired to form a sintered body, and then the sintered body may be cut to form the individual laminates 4.

[0079] The corners of the laminate 4 obtained as described above may be chamfered using a barrel or the like to form an R-shaped surface as shown in Figure 2Aa, or a C-shaped surface as shown in Figure 2Ab. In addition, the end faces 5e and 5f of the laminate 4 may be polished as needed, for example, by barrel polishing or sandblasting.

[0080] (Insulating layer formation process) Next, the process of forming an insulating layer on the outer circumference of the laminate 4, which will form the main body of the element, will be described. In the above-described manufacturing process of the laminate 4, the laminate 4 is fired before forming the insulating layers 16a to 16d. However, in this embodiment, it is preferable to wrap the dielectric sheets 24, which will become the insulating layers 16a to 16d, around the laminate 4 before firing. This will be explained in detail below.

[0081] As shown in Figure 6A, a winding dielectric sheet 24 is placed on the upper surface of the first rolling member 20, and an adhesive sheet 26 is provided on the lower surface of the second rolling member 22. As shown in Figure 6B, one or more laminates 4 are sandwiched between the first rolling member 20 and the second rolling member 22, and in this embodiment, the side surface 5a of the laminate 4 initially adheres to the adhesive sheet 26, forming an adhesive layer 26a. In Figure 6A, the laminate 4 is depicted as being attached to the adhesive sheet 26 on the lower surface of the second rolling member 22, but it is not limited to this, and initially the laminate 4 may simply be placed on the sheet 24 of the first rolling member 20.

[0082] The first rolling member 20 and the second rolling member 22 may be made of the same material or different materials. The first rolling member 20 and the second rolling member 22 may be, for example, plate-shaped or sheet-shaped members with a certain degree of rigidity, and their material is not particularly limited and may be metal, ceramic or plastic, etc.

[0083] The dielectric sheet 24 for wrapping is not particularly limited as long as it is a sheet that becomes the insulating layer 16a to 16d shown in Figure 2A after heat treatment. Examples include a dielectric sheet made of a material substantially the same as or different from the dielectric green sheet used to form the dielectric layer 10 or 11 shown in Figure 1, or other semi-cured dielectric sheets.

[0084] For example, the dielectric sheet 24 is preferably substantially identical in composition to the dielectric green sheet 10a shown in Figure 4A or Figure 4B, as described above, but it may also be different. If the insulating layer has substantially the same composition as the dielectric green sheet, the laminate and the insulating layer can be fired together. Furthermore, it is preferable that the content of components that improve sinterability, such as boron, is high in the minor components of the dielectric material.

[0085] Furthermore, the dielectric sheet 24 preferably contains 1 to 10% more binder and plasticizer combined compared to the dielectric green sheet 10a shown in Figure 4A or Figure 4B. The dielectric sheet 24 is installed on the surface of the first rolling member 20 so as to be peelable and so as not to move laterally.

[0086] Furthermore, the adhesive sheet 26 is installed on the lower surface of the second rolling member 22 in a way that allows it to be peeled off and prevents it from sliding laterally. The adhesive sheet 26 may be made of, for example, a double-sided adhesive sheet, and it is preferable that the adhesive force to the laminate 4 is higher than the adhesive force to the lower surface of the second rolling member 22. The adhesive sheet 26 is made of a resin such as a synthetic polymer such as polyvinyl butyral, acrylic, polyvinyl alcohol, polyvinyl acetate, or epoxy, or a natural polymer such as rosin or terpene.

[0087] As shown in Figure 6B, the second rolling member 22 is lowered relative to the first rolling member 20, and the laminate 4 is pressed against the first rolling member 20 by the second rolling member 22. As a result, a portion of the adhesive sheet 26 is transferred to the side surface 5a of the laminate 4 to form an adhesive film 26a. Next, as shown in Figure 6C, while pressing the laminate 4 against the first rolling member 20 with the second rolling member 22 (the reverse is also acceptable / the same applies below), the second rolling member 22 is moved in a direction that is parallel to the first rolling member 20 (in the direction of the arrow).

[0088] As the second rolling member 22 moves relative to the first rolling member 20, the laminate 4 can be rolled on the first rolling member 20 (or the second rolling member 22) in the circumferential direction of its sides 5a to 5d. When rolling the laminate 4, the relative distance of the second rolling member 22 to the first rolling member 20 may change along with the change in the rolling radius of the laminate 4. In other words, it is preferable that the laminate 4 is always in contact with both the first and second rolling members while rolling.

[0089] As shown in Figure 6C, as the laminate 4 rolls, the adhesive layer 26a formed on the side surface 5a of the laminate 4 is separated from the lower surface of the second rolling member 22 and transferred. At the same time, the adhesive sheet 26 adheres to the side surface 5b of the laminate 4, forming the adhesive layer 26b. The wrapping dielectric sheet 24 may have notches 25 formed in it, and it is preferable that the position of the notches 25 coincides with the rolling start point position of the side surface 5a of the laminate 4 on the surface of the first rolling member 20.

[0090] Furthermore, when the second rolling member 22 is moved in the same direction (direction of the arrow), as shown in Figure 6D, the laminate 4 rolls, and the adhesive layer 26a formed on the side surface 5a of the laminate 4 adheres to the winding dielectric sheet 24, forming an outer peripheral film 24a that becomes the insulating layer 16a. Also, the adhesive sheet 26 adheres to the side surface 5c of the laminate 4, forming an adhesive layer 26c.

[0091] Furthermore, when the second rolling member 22 is moved in the same direction (direction of the arrow), as shown in Figure 6E, the dielectric sheet 24 is separated from the dielectric sheet 24 located on the surface of the first rolling member 20 at the cut 25 and transferred to the side surface 5a of the laminate 4, forming the outer peripheral film 24a. Note that the cut 25 in the dielectric sheet 24 is not necessarily required if the outer peripheral film 24a can be transferred to the side surface 5a of the laminate 4.

[0092] Furthermore, when the second rolling member 22 is moved relative to the other in the same direction, as shown in Figure 6F, the adhesive layer 26b formed on the side surface 5b of the laminate 4 adheres to the winding dielectric sheet 24, forming an outer peripheral film 24b that serves as an insulating layer. Also, the adhesive sheet 26 adheres to the side surface 5d of the laminate 4, forming an adhesive layer 26d.

[0093] Similarly, by moving the second rolling member 22 in the same direction and rolling the laminate 4, the wrapping dielectric sheet 24 adheres to the adhesive layer 26c on the side surface 5c of the laminate 4, as shown in Figure 6G, forming an outer peripheral film 24c that serves as an insulating layer. Furthermore, the wrapping dielectric sheet 24 adheres to the adhesive layer 26d on the side surface 5d of the laminate 4, forming an outer peripheral film 24d that serves as an insulating layer.

[0094] Furthermore, by pressing the laminate 4 toward the first rolling member 20 from the upper part of the second rolling member 22 to which the laminate 4 is attached, the outer peripheral film 24d can be separated from the dielectric sheet 24 located on the first rolling member 20. In this way, the ends of the outer peripheral film 24a and the ends of the outer peripheral film 24d are joined, and a laminate 4 with the outer peripheral films 24a to 24d wrapped around it is obtained, as shown in Figure 6H.

[0095] Next, the laminate 4 with the outer peripheral films 24a to 24d wrapped around it is subjected to drying and binder removal treatment as necessary, followed by firing to obtain a laminate 4 with insulating layers 16a to 16d formed as shown in Figure 2A.

[0096] Furthermore, if necessary, the laminate 4 with the outer peripheral films 24a to 24d wrapped around it may be further rolled between the first rolling member 20 and the second rolling member 22 to form one or more layers of the same outer peripheral films 24a to 24d on top of the outer peripheral films 24a to 24d. Also, if necessary, before the baking process, the laminate 4 with the outer peripheral films 24a to 24d wrapped around it may be deburred by barrel processing or the like.

[0097] After forming the laminate 4 on which insulating layers 16a to 16d are formed, terminal electrodes 6 and 8 are formed on the Y-axis end faces 5e and 5f of the laminate 4, respectively, as shown in Figure 1. To form the terminal electrodes 6 and 8, metal paste is applied to both end faces in the Y-axis direction of the laminate 4 and baked to form a metal paste baked film that will become the electrode film of the terminal electrodes 6 and 8. The method for forming the electrode film of the terminal electrodes 6 and 8 is not particularly limited, and any appropriate method such as applying and baking metal paste, plating, vapor deposition, or sputtering can be used.

[0098] Furthermore, when applying the metal paste to the Y-axis end face of the laminate 4 by dipping, it is preferable to ensure that the metal paste also spreads to the X-axis and Z-axis end faces of the laminate 4. The width of the wetting in the Y-axis direction is preferably 50 μm to 200 μm. The width can be controlled by adjusting the viscosity of the metal paste and the dipping conditions. The curing temperature of the metal paste is preferably 0°C to 50°C higher than the melting point (softening point) of the glass contained in the terminal electrodes 6 and 8.

[0099] A coating layer may be formed on the surface of the electrode film of terminal electrodes 6 and 8 by plating, sputtering, or other methods. The formation of terminal electrodes 6 and 8 is carried out after the formation of insulating layers 16a to 16d.

[0100] (Summary of the embodiments)

[0101] In this embodiment, the thickness of the adhesive sheet 26 shown in Figures 6A to 6G is preferably 0.3 μm to 4 μm, which is about 1 / 5 to 1 / 20 of the thickness of the dielectric sheet 24. Since the adhesive sheet 26 of this thickness is sufficiently thin, as shown in Figure 6G, the adhesive sheet 26 does not interfere, and the ends of the outer peripheral film 24a and the ends of the outer peripheral film 24d made of the dielectric sheet 24 are joined together, making it possible to obtain a laminate 4 in which the outer peripheral films 24a to 24d are continuously and seamlessly wrapped. As a result, there is virtually no gap between the formed insulating layer 16a and insulating layer 16d, and the initiation of cracks is suppressed.

[0102] As described above, the manufacturing method of the multilayer ceramic capacitor 2 according to this embodiment includes a step (rolling transfer method) in which the sides 5a to 5d of the laminate 4 are rolled on a dielectric sheet (transfer layer) 24 of a certain thickness so as to successively bring them into contact, thereby continuously attaching the outer peripheral films 24a to 24d to the sides of the laminate 4. Therefore, the multilayer ceramic capacitor 2 according to this embodiment can be manufactured very easily.

[0103] The dielectric sheet 24 is attached, for example, to the sides 5a to 5d of the laminate 4 before firing, and is fired together with the laminate 4 to form insulating layers 16a to 16d, a portion of which becomes the side gap insulating layer. In this embodiment, the side gap insulating layer is formed by a rolling transfer method, so unlike the coating method, the insulating layer is not formed in unnecessary areas. Therefore, the insulating layers 16a to 16e are not substantially formed on the end faces 5e and 5f of the laminate 4 where the terminal electrodes 6 and 8 are formed and connected to the internal electrode layer 12.

[0104] As a result, even if the laminated body 4, which serves as the element itself, is miniaturized, the connection reliability between the terminal electrodes 6 and 8 and the internal electrode layer 12 is also improved. Note that "insulating layers 16a to 16e are not substantially formed on the end faces 5e and 5f of the laminated body 4" means that they are hardly formed compared to the coating method.

[0105] In the multilayer ceramic capacitor 2 of this embodiment, the insulating layers 16a to 16d are insulating layers that continuously cover multiple sides 5a to 5d along the circumferential direction, and are therefore formed with substantially constant quality (consistent characteristics) even in parts other than the side gap insulating layer. In particular, as shown in Figure 2Aa or Figure 2Ab, even at the corners 17 of the sides 5a and 5b of the laminate 4, the insulating layer 16p has consistent characteristics (for example, pore ratio or dielectric particle size). Furthermore, unlike the edges of insulating layers formed by coating methods, in the multilayer ceramic capacitor 2 of this embodiment, it is not necessary to position the edges of the insulating layer near the corners 17 of the laminate 4.

[0106] In conventional multilayer ceramic capacitors, the edges of the insulating layer formed by the coating method must be positioned near the corners 17 of the laminate 4 so as not to reduce the area of ​​the end faces 5e and 5f of the laminate 4, which are the connection end faces with the terminal electrodes 6 and 8. In contrast, in the multilayer ceramic capacitor 2 of this embodiment, since the insulating layers 16a to 16d can be formed by the rolling transfer method, an insulating layer 16p of consistent quality is formed even near the corners 17 of the laminate 4, compared to other parts. Unlike conventional capacitors, the edges of the insulating layer with a thin thickness are not formed near the corners 17. Therefore, moisture intrusion can be effectively prevented, improving the moisture resistance and reliability of the multilayer ceramic capacitor 2.

[0107] Furthermore, the insulating layers 16a to 16d (including 16p / hereinafter the same) are denser and have superior moisture resistance compared to the ceramic layers composed of dielectric layers 10, 11, etc., which prioritize dielectric properties. Therefore, the insulating layers 16a to 16d effectively protect the exposed edges of the internal electrode layer 12 on the side surface of the laminate 4, further improving reliability.

[0108] Furthermore, the insulating layers 16a to 16d cover all the continuous sides 5a to 5d of the laminate 4 along the circumferential direction. This configuration blocks the entry points to the interface between the insulating layers 16a to 16d and the laminate 4 along the entire circumference of the sides 5a to 5d of the laminate 4, thereby further improving the moisture resistance and reliability of the multilayer ceramic capacitor 2.

[0109] Furthermore, the insulating layers 16a to 16d do not have to completely cover all the continuous sides 5a to 5d of the laminate 4 along the circumferential direction. There may be a gap in the insulating layer 16a on one of the sides 5a to 5d, for example, side 5a. That is, on one of the sides 5a to 5d of the laminate 4 (for example, 5a), the edge of the insulating layer 16a is located near the center in the X-axis direction of side 5a, which is far from the corner of the laminate 4, and a part of side 5a of the laminate 4 may be exposed through the gap between these edges.

[0110] To form such an insulating layer around the side surface of the laminate 4, the dielectric sheet 24 should be started winding from near the center in the X-axis direction on the side surface 5a of the laminate 4 and finished winding near the center in the X-axis direction on the same side surface 5a of the laminate 4.

[0111] In this embodiment, the composition of the insulating layers 16a to 16d can be substantially uniform along the circumferential direction. The uniform composition of the insulating layers 16a to 16d results in uniform moisture resistance along the circumferential direction, reducing the starting points for degrading moisture resistance and improving the reliability of the multilayer ceramic capacitor 2. Furthermore, forming the insulating layers 16a to 16d by the rolling transfer method makes it easier to form insulating layers 16a to 16d with substantially uniform composition along the circumferential direction.

[0112] In this embodiment, the thickness of the insulating layers 16a to 16d can be formed by firing after winding one or more layers of dielectric sheet 24, and can be, for example, 3 μm to 40 μm. In order to form the insulating layers 16a to 16d from a dielectric sheet of uniform thickness, the thickness of the insulating layers 16a to 16d is substantially uniform along the circumferential direction.

[0113] As mentioned above, when the insulating layer 16b and the dielectric layer 11 shown in Figure 2Aa are made of substantially the same material, it is difficult to clearly measure the interface between the dielectric layer 11 and the insulating layer 16b from a cross-sectional photograph of the laminate 4. However, if the pore ratio (or particle size) at a predetermined depth from the surface of the insulating layer 16p at the corner 17 and the pore ratio (or particle size) at a predetermined depth from the surfaces of the insulating layers 16a and 16b are measured and found to be substantially the same, it can be estimated that the thickness of the insulating layers 16a to 16b is substantially uniform along the circumferential direction. Similarly, it can also be estimated that the thickness of the insulating layers 16a to 16d is substantially uniform along the circumferential direction.

[0114] By making the thickness of the insulating layers 16a to 16d uniform, the starting points for degrading moisture resistance are reduced, improving the moisture resistance and reliability of the multilayer ceramic capacitor 2. Since the insulating layers 16a to 16d can be formed by the rolling transfer method, the thickness of the insulating layers 16a to 16d tends to be substantially uniform along the circumferential direction.

[0115] Furthermore, in this embodiment, as shown in Figure 2Aa or Figure 2ab, the thickness tp of the insulating layer 16p at the corner 17 of the laminate 4 can be substantially the same as the thickness tz or tx of the insulating layers 16a, 16b at at least one of the two sides 5a, 5b of the laminate 4 connected to the corner 17. In particular, by making the thickness tp of the insulating layer 16p at the corner 17 of the element 3 the same as the thickness tz or tx of other parts, the moisture resistance and reliability of the multilayer ceramic capacitor 2 are improved. Since the insulating layer 16p can be formed by a rolling transfer method, the thickness tp of the insulating layer 16p at the corner 17 of the element 3 tends to be substantially uniform compared to the thickness tz or tx of other parts.

[0116] In this embodiment, since the outer periphery of the laminate 4 is completely covered by the insulating layers 16a to 16d, the edges of the interface between the insulating layers 16a to 16d and the laminate 4 can be completely covered from the outside air, thereby further improving durability and moisture resistance.

[0117] Furthermore, as shown in Figures 1 and 2B, in this embodiment, terminal electrodes 6 and 8 are formed on the end faces 5e and 5f of the laminate 4, and the edges of the terminal electrodes 6 and 8 cover a portion of the insulating layers 16a to 16d located on the sides 5a to 5d of the laminate 4. Therefore, at the end faces 5e and 5f of the laminate 4, the terminal electrodes 6 and 8 can cover the edges of the interface between the insulating layers 16a to 16d and the laminate 4, thereby improving durability and moisture resistance.

[0118] In this embodiment, an insulating layer is formed on the laminate 4 by firing together the dielectric sheet wrapped around the laminate 4 before firing. By forming an insulating layer in this way, the moisture resistance of the electronic components can be improved, and their durability against external environmental changes such as thermal shock and physical shock can be enhanced.

[0119] The insulating layers 16a to 16d are formed from a single winding dielectric sheet 24, and are continuous with each other, so that the interface between the insulating layers 16a to 16d and the laminate 4 is not exposed to the outside. Therefore, moisture and other elements are less likely to enter the interface, and cracks originating from the interface can be effectively suppressed.

[0120] Furthermore, in this embodiment, in the cross-section shown in Figure 2A, the variation in the arrangement of the internal electrode layers 10 of the laminate 4 at the X-axis ends can be kept within, for example, 5 μm.

[0121] In this embodiment, it is preferable to perform the sintering of the laminate 4 and the baking of the outer peripheral films 24a to 24d simultaneously, but the baking of the outer peripheral films 24a to 24d may be performed after the sintering of the laminate 4.

[0122] Second Embodiment The multilayer ceramic capacitor according to this embodiment differs from the first embodiment only in the method of forming the insulating layer on the outer periphery of the laminate 4. Therefore, the description of the common parts will be omitted, and the differences will be described in detail below. Parts not described below are the same as those described in the first embodiment.

[0123] The manufacturing method of the multilayer ceramic capacitor according to this embodiment differs from the manufacturing method of the multilayer ceramic capacitor according to the first embodiment in that it involves forming insulating layers 16a to 16d on the outer periphery of the sides 5a to 5d of the laminate 4, as shown in Figures 7A to 7F.

[0124] As shown in Figure 7A, a wrapping dielectric sheet 24 is laid on the upper surface of the first rolling member 20, and an adhesive sheet 26 is attached to the upper surface of the wrapping dielectric sheet 24. In this embodiment, unlike the first embodiment, an adhesive layer is not formed on the second rolling member 22, but the second rolling member 22 itself may have adhesive properties.

[0125] The adhesive second rolling member 22 is not particularly limited and may be a sheet where the surface of the sheet material itself is the adhesive surface, such as a foam sheet, a rubber sheet such as silicone, an acrylic tape, or a UV tape (a tape whose adhesive strength weakens when exposed to UV light). Examples of resins that make up the foam sheet include urethane, acrylic, silicone, polyester, and polyurethane.

[0126] As shown in Figure 7B, the second rolling member 22 is lowered, and the laminate 4 is pressed against the first rolling member 20 by the second rolling member 22. The side surface 5a of the laminate 4 adheres to the adhesive sheet 26, forming an outer peripheral film 24a which will become the adhesive layer 26a and the insulating layer 16a. In addition, the winding dielectric sheet 24 may have notches 25 formed therein, and the position of the notches 25 coincides with the edge position of the side surface 5d of the laminate 4.

[0127] As shown in Figure 7C, when the second rolling member 22 presses the laminate 4 against the first rolling member 20, and the second rolling member 22 is moved in the direction of the arrow in the same manner as in the first embodiment, the laminate 4 rolls, and the outer film 24a is separated from the winding dielectric sheet 24 by the notch 25.

[0128] Furthermore, when the second rolling member 22 is moved in the same direction as described above, the laminate 4 rolls, as shown in Figure 7D, and the adhesive sheet 26 adheres to the side surface 5b of the laminate together with the sheet 24, forming an outer peripheral film 24b which becomes the adhesive layer 26b and the insulating layer 16b.

[0129] Furthermore, when the second rolling member 22 is moved in the same direction as described above, the laminate 4 rolls, as shown in Figure 7E, and the adhesive sheet 26 adheres to the side surface 5c of the laminate together with the sheet 24, forming an outer peripheral film 24c which becomes the adhesive layer 26c and the insulating layer 16c.

[0130] Furthermore, by rolling the laminate 4, as shown in Figure 7F, the laminate 4 rolls, the adhesive sheet 26 adheres to the side surface 5d of the laminate, and an outer peripheral film 24d, which becomes the adhesive layer 26d and the insulating layer 16d, is formed.

[0131] Furthermore, as shown in Figure 7F, by pressing the laminate 4 toward the first rolling member 20 from the upper part of the second rolling member 22 to which the laminate 4 is attached, the outer peripheral film 24d can be separated from the winding dielectric sheet 24. In this way, the end of the outer peripheral film 24a and the outer peripheral film 24d are joined, and the outer peripheral films 24a to 24d shown in Figure 6H are wound around to obtain the laminate 4. The outer peripheral films 24a to 24d shown in Figure 6H become the insulating layers 16a to 16d shown in Figure 2A after firing.

[0132] Third Embodiment The multilayer ceramic capacitor according to this embodiment differs from the first or second embodiment only in the method of forming the insulating layer on the outer periphery of the laminate 4. Therefore, the description of the common parts will be omitted, and the differences will be described in detail below. Parts not described below are the same as those described in the embodiments above.

[0133] In the manufacturing method of the multilayer ceramic capacitor according to this embodiment, as shown in Figures 8A to 8F, the configuration of the dielectric sheet in the step of forming an insulating layer on the outer periphery of the laminate 4 differs from that of the manufacturing method of the multilayer ceramic capacitor according to the first embodiment.

[0134] As shown in Figure 8A, a wrap-around adhesive dielectric sheet 28 is laid on the upper surface of the first rolling member 20. The wrap-around adhesive dielectric sheet 28 can be manufactured in the same manner as the dielectric sheet 24 of the first embodiment, and the dielectric sheet 28 can be made adhesive by adjusting the content or composition of, for example, the binder and / or dispersion medium and other tackifying components.

[0135] As a binder, for example, ethylcellulose, polyvinyl butyral, etc., can be used, and it is preferable to increase the content compared to the first embodiment. As a dispersion medium, for example, terpineol, acetone, etc., are exemplified, and as other tackifying components, examples include synthetic polymers such as polyvinyl butyral, acrylic, polyvinyl alcohol, polyvinyl acetate, epoxy, natural polymers such as rosin, terpenes, and plasticizers such as dioctyl phthalic acid, and it is preferable to increase the content compared to the first embodiment.

[0136] As shown in Figure 8B, the second rolling member 22 is lowered, and the laminate 4 is pressed against the first rolling member 20 by the second rolling member 22. The side surface 5a of the laminate 4 adheres to the wrapping adhesive dielectric sheet 28, forming an outer peripheral film 28a that becomes the insulating layer 16a. In addition, the wrapping adhesive dielectric sheet 28 may have notches 29 formed in it.

[0137] As shown in Figure 8C, when the second rolling member 22 presses the laminate 4 against the first rolling member 20, and the second rolling member 22 is moved in the direction of the arrow in the same manner as in the embodiment described above, the laminate 4 rolls, the outer peripheral film 28a adheres to the laminate 4, and is pulled away from the surface of the first rolling member 20.

[0138] Furthermore, when the second rolling member 22 is moved in the same direction as described above, as shown in Figure 8D, the laminate 4 rolls, and the adhesive dielectric sheet 28 for wrapping adheres to the side surface 5b of the laminate, forming an outer peripheral film 28b which will become the insulating layer 16b. Furthermore, when the second rolling member 22 is moved in the direction of the arrow, as shown in Figure 8E, the laminate 4 rolls, and the adhesive dielectric sheet 28 for wrapping adheres to the side surface 5c of the laminate, forming an outer peripheral film 28c which will become the outer peripheral layer 16c. Further rolling of the laminate 4 causes the laminate 4 to roll, as shown in Figure 8F, and the adhesive dielectric sheet 28 for wrapping adheres to the side surface 5d of the laminate, forming an outer peripheral film 28d which will become the outer peripheral layer 16d.

[0139] Furthermore, as shown in Figure 8F, by pressing the laminate 4 toward the first rolling member 20 from the upper part of the second rolling member 22 to which the laminate 4 is attached, the outer peripheral film 28d can be separated from the wrapping adhesive dielectric sheet 28. In this way, the end of the outer peripheral film 28a and the outer peripheral film 28d are joined, and as shown in Figure 8G, the outer peripheral films 28a to 28d are wrapped around to obtain the laminate 4. The outer peripheral films 28a to 28d shown in Figure 8G become the insulating layers 16a to 16d shown in Figure 2A after firing.

[0140] In this embodiment, the sides 5a to 5d and / or end faces 5e, 5f of the laminate 4 may be cleaned before the outer peripheral films 28a to 28d are wrapped around it to form the laminate 4.

[0141] When performing a cleaning process, it is preferable that the surfaces of the first rolling member 20 and the second rolling member 22 are adhesive. The first rolling member 20 and the second rolling member 22, which are adhesive, may be made of the same material or different materials.

[0142] The first rolling member 20 and the second rolling member 22 are not particularly limited and may be sheets where the surface of the sheet material itself is the adhesive surface, such as foam sheets, rubber sheets such as silicone, acrylic tapes, or UV tapes (tapes whose adhesive strength weakens when exposed to UV light). Examples of resins that make up the foam sheet include urethane, acrylic, silicone, polyester, and polyurethane.

[0143] First, as shown in Figure 9A, the second rolling member 22 is lowered, and the laminate 4 is pressed down by the second rolling member 22 onto the portion of the first rolling member 20 where the adhesive dielectric sheet 28 for wrapping is not laid. Next, as shown in Figure 9B, when the second rolling member 22 is moved in the direction of the arrow in the same manner as in the embodiment described above, the laminate 4 rolls, and the side surface 5a of the laminate 4 that was attached to the adhesive first rolling member 20 and the side surface 5c of the laminate 4 that was attached to the second rolling member 22 peel off from the upper surface of the first rolling member 20 and the lower surface of the second rolling member 22. At that time, dirt and other debris are transferred from the surfaces of the side surfaces 5a and 5c of the laminate 4 to the contact surface of the first rolling member 20 or the second rolling member 22, and the side surfaces 5a and 5c can be cleaned.

[0144] Furthermore, when the second rolling member 22 is moved in the direction of the arrow, the laminate 4 rolls, and the side surface 5b of the laminate 4 adheres to the first rolling member 20, while the side surface 5d of the laminate 4 adheres to the second rolling member 22. At this time, the position of the side surface 5c of the laminate 4 coincides with the position of the end of the wrapping adhesive dielectric sheet 28.

[0145] Furthermore, when the second rolling member 22 is moved in the direction of the arrow, the laminate 4 rolls, and the side surface 5b of the laminate 4 that was attached to the first rolling member 20 and the side surface 5d of the laminate 4 that was attached to the second rolling member 22 peel off from the upper surface of the first rolling member 20 and the lower surface of the second rolling member 22. At that time, dirt and other debris are transferred from the surfaces of side surfaces 5b and 5d of the laminate 4 to the contact surface of the first rolling member 20 or the second rolling member 22, and side surfaces 5b and 5d can be cleaned.

[0146] In other words, during the process in which the sides 5a to 5d of the laminate 4 peel off from the upper surface of the first rolling member 20 and the lower surface of the second rolling member 22, cutting debris and other waste (for example, setter residue attached during firing) that were adhering to the sides 5a to 5d of the laminate 4 can be removed by adhering them to the upper surface of the first rolling member 20 and the lower surface of the second rolling member 22.

[0147] In Figure 9B, when the second rolling member 22 is moved further in the same direction as described above, the laminate 4 rolls, and the side surface 5c of the laminate 4 adheres to the wrapping adhesive dielectric sheet 28, forming an insulating layer 16c. This state is the same as the laminate 4 in Figure 8B but with the top and bottom reversed. By moving the second rolling member 22 in the direction of the arrow, the process of forming insulating layers 16a to 16d on the outer circumference of the side surfaces 5a to 5d of the laminate 4 can be performed continuously with the cleaning process of the laminate 4.

[0148] Furthermore, from the state shown in Figure 9A, by moving the second rolling member 22 in the Y-axis direction, the laminated body 4 can be rotated twice, thereby cleaning the end faces 5e and 5f of the laminated body 4.

[0149] In this embodiment, both the first rolling member 20 and the second rolling member 22 are adhesive, but the first rolling member 20 does not necessarily have to be adhesive. In that case, by moving the position where the laminate 4 is pressed against the first rolling member 20 away from the edge of the wrapping adhesive dielectric sheet 28 and increasing the number of rolling cycles, all sides 5a to 5d of the laminate 4 can be cleaned. Furthermore, by changing the direction of rolling, the end faces 5e and 5f of the laminate 4 can also be cleaned.

[0150] Fourth Embodiment As shown in Figure 3A, the multilayer ceramic capacitor according to this embodiment differs from the first to third embodiments only in the configuration of the outer casing region 11 of the laminate 4. Therefore, the description of the common parts will be omitted, and the differences will be described in detail below. Parts not described below are the same as those described in the embodiments above.

[0151] In this embodiment, the outer region 11 is made by providing one or more layers of the same dielectric material as the inner dielectric layer 10 as the outer dielectric layer, making it extremely thin compared to the thickness of the outer region 11 shown in Figure 2A. Furthermore, in this embodiment, the outer region 11 shown in Figure 3A may not be formed at all.

[0152] In other words, in the element body 4, the outer region 11 in the stacking direction (Z-axis direction) of each layer forms the side surface, and insulating layers 16a and 16d are formed on the side surfaces 5a and 5d of the outer region 11. In this embodiment, the thickness of the outer region 11 is about the same as the thickness of the ceramic layer 10 that forms the inner region 13. Note that the composition of the insulating layers 16a to 16p may differ from the composition of the outer region 11.

[0153] In this embodiment, even if the outer layer 11 is of the same thickness as the inner dielectric layer 10, or even if the outer layer 11 is absent, the insulating layers 16a to 16d cover the sides 5a to 5d of the laminate 4, thus providing sufficient protection and strength, improving the durability and moisture resistance of the multilayer ceramic capacitor 2, and enhancing the reliability of long-term use.

[0154] Fifth Embodiment As shown in Figure 3B, the multilayer ceramic capacitor according to this embodiment differs from the first to fourth embodiments only in the configuration of the ends of the inner dielectric layer 10 and the internal electrode layer 12. The description of the common parts will be omitted, and the differences will be described in detail below. The parts not described below are the same as those described in the embodiments above.

[0155] In this embodiment, dielectric gaps 18b and 18d are formed at both ends of the inner dielectric layer 10 and the internal electrode layer 12 in the X-axis direction. That is, the outer sides of the dielectric gaps 18b and 18d in the X-axis direction form the sides 5b and 5d of the laminate 4. In this way, the formation of dielectric gaps 18b and 18d covers the ends of the internal electrode layer, thereby improving the durability and moisture resistance of the multilayer ceramic capacitor 2 and enhancing its reliability for long-term use.

[0156] The laminate 4 of this embodiment is obtained by firing the green chip 4a shown in Figure 5B and going through the above-described process of forming the insulating layers 16a to 16d. The green chip 4a shown in Figure 5B is obtained by changing the pattern shape of the internal electrode pattern layer 12a in the above-described manufacturing process of the laminate, so that the pattern shape is such that the internal electrode pattern layer 12a is interrupted at the C1 cross-section shown in Figure 4A.

[0157] In addition, Figure 3C shows that an insulating layer is formed on the outer periphery of the laminate 4, where the thickness of the outer region 11 (including dielectric gaps 18b and 18d) in Figure 3B is approximately the same as that of the dielectric layer 10 forming the inner region. Even with this structure, it is the same as in this embodiment.

[0158] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways within the scope of the present invention.

[0159] For example, in the multilayer ceramic capacitor 2 of the first embodiment shown in Figure 1, at least one of the outer dielectric layers 11, 11 may be omitted. Also, in the above-described embodiment, the main component of the insulating layers 16a to 16d may be made of something other than a dielectric, for example, the insulating layers 16a to 16d may be made of ceramic, aluminum, epoxy resin, polyimide resin, etc.

[0160] Furthermore, the electronic component according to the present invention is not limited to multilayer ceramic capacitors, but can be applied to other electronic components as well. Examples of other electronic components include all electronic components in which a functional part is formed on the side surface of the element body (the outer surface other than the outer surface on which the terminal electrodes are formed), such as bandpass filters, chip inductors, multilayer three-terminal filters, piezoelectric elements, chip thermistors, chip varistors, chip resistors, and other surface-mount (SMD) chip-type electronic components. [Explanation of symbols]

[0161] 2… Multilayer ceramic capacitor 3... Element 4… Laminate (element body) 4a... Green chip 5a~5d… Side 5e,5f… End face 6... 1st terminal electrode 6a… Electrode paste film 8... 2nd terminal electrode 10… Inner dielectric layer (ceramic layer) 10a... Inner green sheet 11… Exterior layer (ceramic layer) 11a... Outer green sheet 12… Internal electrode layer 12α,12β…Drawer part 12a… Internal electrode pattern layer 13… Interior Design Area 14… Capacity area 15A,15B…Drawer area 16a, 16b, 16c, 16d, 16p… Insulating layer 16a1,16b1,16c1,16d1...outer surface 17... Corner 18b, 18d… Dielectric gap section 20… First rolling member 22… Second rolling member 24… Dielectric sheet 24a, 24b, 24c, 24d...Peripheral membrane 25...cut 26… Adhesive sheet 26a,26b,26c,26d...adhesive film 28…Adhesive dielectric sheet 28a, 28b, 28c, 28d...Peripheral membrane 29...cut

Claims

1. An electronic component having an element body with multiple sides along the circumferential direction, The element body has an insulating layer that continuously covers multiple sides along the circumferential direction. On one of the sides of the element body, there is a gap between the edges of the insulating layer in which a portion of the side of the element body is exposed. The corners where the sides of the element body intersect are formed as chamfered portions with a C-chamfer. The insulating layer is formed with a uniform thickness along the chamfered portion at the corner, An electronic component in which, including the insulating layer formed at the corner, the pore ratio of the insulating layer and / or the particle size of the dielectric particles are substantially the same along the circumferential direction, except for the gap portion.

2. The electronic component according to claim 1, wherein the pore ratio at a predetermined depth from the surface of the insulating layer at a corner of the element body is substantially the same as the pore ratio at a predetermined depth from the surface of the insulating layer at at least one of the two sides of the element body connected to the corner.

3. The electronic component according to claim 1 or 2, wherein the pore ratio at a predetermined depth from the surface of the insulating layer is substantially the same along the circumferential direction.

4. The insulating layer contains ceramic particles, The electronic component according to any one of claims 1 to 3, wherein the particle size of the ceramic particles at a predetermined depth from the surface of the insulating layer is substantially the same along the circumferential direction.

5. The electronic component according to any one of claims 1 to 4, wherein the insulating layer is made of a dielectric material containing ceramic particles having substantially the same or different particle sizes as the dielectric layer of the element body.

6. The electronic component according to any one of claims 1 to 5, wherein the insulating layer is made of a dielectric material having substantially the same or a different composition as the dielectric layer of the element body.

7. The electronic component according to claim 6, wherein the element body has a laminated structure in which the dielectric layer and the internal electrode layer are stacked.

8. The electronic component according to claim 7, wherein the element body has an outer layer region in the stacking direction of each layer that forms a side surface, and the insulating layer is formed on the side surface region of the outer layer region.

9. The electronic component according to claim 8, wherein the exterior region is formed to be thicker than the dielectric layer forming the interior region.

10. The electronic component according to claim 8 or 9, wherein the thickness of the outer region is approximately the same as the thickness of the dielectric layer forming the inner region.

11. The electronic component according to any one of claims 8 to 10, wherein the exterior region is also formed in a direction perpendicular to the stacking direction of the element body.

12. The electronic component according to any one of claims 8 to 11, wherein the dielectric layer forms the exterior region.

13. The electronic component according to any one of claims 8 to 12, wherein the composition of the insulating layer and the composition of the outer casing region are different.

14. The electronic component according to any one of claims 6 to 13, wherein the insulating layer is composed of a composition that contains a larger amount of components that improve the sinterability of the insulating layer than the dielectric layer of the element body.

15. The electronic component according to claim 14, which references any one of claims 7 to 13, wherein a terminal electrode is formed on the end face of the element body that intersects the side surface, and is connected to the exposed end of the internal electrode layer.

16. The electronic component according to claim 15, wherein the edge of the terminal electrode covers the edge of the insulating layer.

17. The dielectric layer and the internal electrode layer are each a plurality, The insulating layer is formed on the side surface of the element body so as to cover the exposed sides of the plurality of internal electrode layers. The electronic component according to claim 14, claim 15, or claim 16, which references any one of claims 7 to 13, characterized in that the positional variation of the exposed sides of the plurality of internal electrode layers that contact the insulating layer is within a predetermined range.

18. The electronic component according to any one of claims 1 to 17, wherein the composition of the insulating layer is substantially uniform along the circumferential direction.

19. The electronic component according to any one of claims 1 to 18, wherein the thickness of the insulating layer is 3 μm to 40 μm.

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