Electronic component, circuit board arrangement, electronic device, and method of manufacturing electronic component

Abstract

In order to reduce moisture-resistant degradation and cracking, an electronic component in one embodiment includes: an element body having a contour having a pair of end surfaces and a plurality of side surfaces, each side surface being connected to the end surfaces and extending from one end surface to the other end surface, and including at least one conductor located within the element body; base layers, each of which is in contact with the side surface and one end surface; and Ni layers respectively formed on the base layer, each Ni layer being disposed on the side surface and the corresponding end surface. Each Ni layer has at least one thickest portion disposed on at least one side, and a thickness of the thickest portion is at least 30% greater than a thickness of a portion of the Ni layer disposed on the corresponding end face.

Description

Technical Field

[0001] The present invention relates to an electronic component, a circuit board arrangement, an electronic device and a method of manufacturing an electronic component. Background Art

[0002] Surface mount components (chip components) are called electronic components, such as laminated ceramic capacitors and laminated inductors, which have internal conductors (e.g., electrodes and windings) and external electrodes connected to the internal conductors. The surface mount components are mounted on a substrate by bonding the external electrodes to the substrate using, for example, solder.

[0003] For example, Patent Document 1 discloses a laminated ceramic capacitor having a sintered electrode (Cu layer) formed of a conductive paste containing a glass component and Cu powder, a Ni plating layer formed on the surface of the Cu layer, and a Sn plating layer formed on the Ni plating layer.

[0004] Patent Literature:

[0005] Patent Document 1: JP 2015-39014A Summary of the invention

[0006] If the Ni plating layer has insufficient adhesion to the Cu layer, moisture may penetrate between them, causing moisture resistance degradation of electronic components. Adhesion can be improved by increasing the thickness of the Ni plating layer, but if the Ni plating layer is too thick, residual stress will increase, causing thermal cycle cracks or flex cracks.

[0007] Therefore, the present invention is directed to reducing moisture degradation and cracking.

[0008] In order to solve the above problems, according to one aspect of the present invention, there is provided an electronic component, which includes: a component body, the outline of the component body has a pair of end faces and a plurality of side faces, each side face is connected to the end face and extends from one end face to the other end face, and the component body includes at least one conductor located in the component body; a base layer, each base layer is in contact with the side face and one end face; and Ni layers formed on the base layers, respectively, each Ni layer is arranged on the side face and the corresponding end face. Each Ni layer has at least one thickest portion arranged on at least one side face, and the thickness of the thickest portion is at least 30% greater than the thickness of the portion of the Ni layer arranged on the corresponding end face.

[0009] In one embodiment of the present invention, each base layer is a Cu layer.

[0010] In one embodiment of the present invention, the electronic component further includes upper metal layers formed on the Ni layers, respectively.

[0011] In one embodiment of the present invention, each base layer is a Cu layer, and each upper metal layer is a Sn layer.

[0012] In one embodiment of the present invention, the thickness of the thickest portion is at least 20% greater than the thickness of at least one thinnest portion disposed on at least one side.

[0013] In one embodiment of the present invention, each Ni layer has a thickest portion which is located on a side surface and is farther from the corresponding end surface than a middle portion between an edge farthest from the corresponding end surface and an edge closest to the corresponding end surface.

[0014] In one embodiment of the present invention, the element body has a first side surface connected to the end surface and second side surfaces each connected to the first side surface and the end surface, and each Ni layer has a thickest portion disposed on a boundary between the first side surface and the second side surface.

[0015] In one embodiment of the present invention, the thickness of the thickest portion of each Ni layer is 3.5 to 5.5 microns.

[0016] In one embodiment of the present invention, the thickness of the portion of each Ni layer disposed on the corresponding end surface is 2.5 to 4.0 micrometers.

[0017] In one embodiment of the present invention, the thickness of the thinnest portion of each Ni layer is at least 3.0 microns.

[0018] In one embodiment of the present invention, the thickness of a portion of each Ni layer farthest from the corresponding end face is at least 30% greater than the thickness of a portion of the Ni layer disposed on a boundary between the end face and each side face.

[0019] In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a circuit board arrangement including any one of the above-mentioned electronic components and a substrate on which the electronic component is mounted by solder.

[0020] In order to solve the above problems, according to another aspect of the present invention, an electronic device including the above circuit board arrangement is provided.

[0021] In order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a method for manufacturing an electronic component, the method comprising: forming a base layer on a component body, the contour of the component body having a pair of end faces and a plurality of side faces, each side face being connected to the end face and extending from one end face to another end face, and the component body having at least one conductor located in the component body, wherein each base layer is in contact with the side face and one end face; reducing the thickness of at least a portion of each base layer, the portion being in contact with at least one side face; and forming Ni layers on the base layers, respectively, wherein each Ni layer is arranged on the side face and the corresponding end face.

[0022] According to one embodiment of the invention, the thickness is reduced by sandblasting.

[0023] According to the present invention, moisture resistance degradation and cracking can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a perspective view showing an example of the structure of the capacitor according to the first embodiment of the present invention.

[0025] Figure 2 is a cross-sectional view showing a capacitor according to a first embodiment.

[0026] Figure 3 It is a schematic diagram used to describe the causes of cracks.

[0027] Figure 4 is a graph showing the measured thickness of the Ni layer.

[0028] Figure 5 is a flowchart showing a method for manufacturing a capacitor according to the first embodiment.

[0029] Figure 6 is a first cross-sectional view illustrating a method for manufacturing the capacitor according to the first embodiment.

[0030] Figure 7 is a second cross-sectional view illustrating the method for manufacturing the capacitor according to the first embodiment.

[0031] Figure 8 is a third cross-sectional view illustrating the method for manufacturing the capacitor according to the first embodiment.

[0032] Fig. 9 is a fourth cross-sectional view illustrating the method for manufacturing the capacitor according to the first embodiment.

[0033] Fig.10 is a fifth cross-sectional view illustrating the method for manufacturing the capacitor according to the first embodiment.

[0034] Fig.11 is a sixth cross-sectional view illustrating the method for manufacturing the capacitor according to the first embodiment.

[0035] Fig.12 is a graph showing the difference in thickness of the base layer (Cu layer) with and without sandblasting.

[0036] Fig.13 is a graph showing the difference in Ni layer thickness with and without sandblasting.

[0037] Fig.14 is a cross-sectional view showing a capacitor according to a second embodiment.

[0038] Fig.15is a cross-sectional view showing a capacitor according to a third embodiment.

[0039] Fig.16 is a cross-sectional view showing a capacitor according to a fourth embodiment.

[0040] Fig.17 is a cross-sectional view showing a capacitor according to a fifth embodiment.

[0041] Fig.18 is a cross-sectional view showing an example of a chip inductor according to a sixth embodiment. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention, and not all combinations of features in the embodiments are necessary for the structure of the present invention. The structure of the embodiments may be appropriately modified or changed according to the specifications and various conditions (such as use conditions and use environment) of the equipment to which the present invention is applied.

[0043] The technical scope of the present invention is defined by the scope of the claims, and is not limited by the following embodiments. In order to facilitate understanding of the structure, the drawings cited in the following description may differ from the actual structure in terms of proportion, shape, etc. The description of the following drawings may appropriately refer to the structural elements shown in the drawings described previously.

[0044] First embodiment

[0045] Figure 1 and Figure 2 An example of the structure of the capacitor according to the first embodiment of the present invention is shown. Figure 1 Showing a stereogram, Figure 2 Shown along Figure 1 In the present embodiment, the capacitor 1 is used as an example of an electronic component.

[0046] The capacitor 1 according to the present embodiment is, for example, a multilayer ceramic capacitor, and has an element body 11 and a pair of external electrodes 12 .

[0047] like Figure 1 As shown in (A), the circuit board arrangement 2 according to the embodiment of the present invention includes a capacitor 1 and a substrate 2a on which the capacitor 1 is mounted. The substrate 2a has a pad portion 3. The capacitor 1 is mounted on the substrate 2a by soldering the external electrodes 12 to the pad portions 3, respectively.

[0048] The circuit board arrangement 2 may be provided in various electronic devices. Electronic devices using the circuit board arrangement 2 may include electrical components in vehicles, servers, board-shaped computers, and various other electronic devices.

[0049] In this specification, unless otherwise understood from the context, expressions about directions are based on Figure 1 The X-axis direction, Y-axis direction and Z-axis direction are respectively referred to as the "length" direction, the "width" direction and the "height" direction. The "height" direction can also be referred to as the "thickness" direction. The capacitor 1 is mounted on the substrate 2a so that one side of the capacitor 1 in the height direction Z ( Figure 2 The lower side in the figure) faces the substrate 2a.

[0050] The capacitor 1 has a rectangular parallelepiped shape, and the component body 11 also has a rectangular parallelepiped shape. However, some faces of the capacitor 1 and the component body 11 may be flat, curved or stepped. In addition, some of the eight vertices and twelve edges of the capacitor 1 and the component body 11 may be rounded or chamfered. The external dimensions of the capacitor 1 are preferably in the range of "0201" (length = 0.25 mm, width = 0.125 mm) according to the Japanese Industrial Standard (JIS) to "4532" (length = 4.5 mm, width = 3.2 mm) according to JIS, but may be any other size.

[0051] In this specification, the outline of the capacitor 1 and the element body 11 may be referred to as a "rectangular parallelepiped" even if some faces of the capacitor 1 and the element body 11 are curved or uneven, and / or even if some vertices and edges of the capacitor 1 and the element body 11 are rounded or chamfered. In other words, the term "rectangular parallelepiped" used herein does not necessarily mean a rectangular parallelepiped in a strict mathematical sense.

[0052] The element body 11 has end faces 111 at both ends in the length direction X, and the two end faces 111 are arranged opposite to each other. The element body 11 has a first side face 112 at both ends in the width direction Y, and a second side face 113 at both ends in the height direction Z. When the element body 11 is pressed in manufacturing the capacitor 1, the second side face 113 is a surface to which pressure is mainly applied. The first side face 112 is a cut surface that has been cut when the capacitor 1 is manufactured.

[0053] Each of the first side surface 112 and the second side surface 113 is a surface connected to the end surface 111 and extending from one of the end surfaces 111 to the other of the end surfaces 111. Each second side surface 113 is a surface connected to two first side surfaces 112 and two end surfaces 111.

[0054] The element body 11 has an internal structure including a dielectric layer 115 and an internal electrode 116 .

[0055] The main component of the material for the dielectric layer 115 may be, for example, a ceramic material having a perovskite structure. The content of the main component may be 50 atomic percent (50 at%) or more. The ceramic material of the dielectric layer 115 may be, for example, barium titanate, strontium titanate, calcium titanate, magnesium titanate, barium strontium titanate, calcium barium titanate, calcium zirconate, barium zirconate, calcium zirconate titanate, or titanium oxide.

[0056] The internal electrodes 116 are alternately stacked with the dielectric layers 115 interposed therebetween. Figure 2 2 shows an example in which a total of five layers of internal electrodes 116 are stacked, but the number of layers of the internal electrodes 116 stacked is not limited.

[0057] The material for the internal electrode 116 may be a metal such as Cu (copper), Fe (iron), Zn (zinc), Al (aluminum), Ni (nickel), Pt (platinum), Pd (palladium), Ag (silver), Au (gold) or Sn (tin), or may be an alloy containing at least one of these metals. Each internal electrode 116 extends along the second side surface 113 in the XY plane. Each internal electrode 116 reaches one of the end surfaces 111 of the element body 11. The internal electrodes 116 are alternately connected to one and the other of a pair of external electrodes 12. In the width direction Y, both ends of each internal electrode 116 are covered by the dielectric layer 115.

[0058] A pair of external electrodes 12 are formed on the longitudinal ends of the element body 11 so that they are separated from each other in the length direction X. Each external electrode 12 is formed to cover the corresponding end surface 111 of the element body 11, the adjacent portion of the first side surface 112, and the adjacent portion of the second side surface 113. The thickness of each external electrode 12 is, for example, 10 to 40 micrometers.

[0059] like Figure 1 As shown in (B), the portion of the external electrode 12 covering the end face 111 of the element body 11 may be referred to as the "end face side 12a", and the portion of the external electrode 12 covering the first side face 112 or the second side face 113 may be referred to as the "side face side 12b". In addition, in each side face side 12b of the external electrode 12, the portion adjacent to the corresponding end face 111 may be referred to as the "proximal portion 12c", and the portion farthest from the corresponding end face 111 may be referred to as the "distal portion 12d".

[0060] Each external electrode 12 includes a base layer 121, a Ni layer 122, and an upper metal layer 123. The material of the base layer 121 includes a glass component (Si (silicon)), the main component of which may be a metal such as Cu, Fe, Zn, Al, Pt, Pd, Ag, Au, or Sn, or may be an alloy containing at least one of these metals. The glass component dispersed like an island in the base layer 121 reduces the difference in thermal expansion coefficient between the element body 11 and the base layer 121 to alleviate the thermal stress applied to the base layer 121. The base layer 121 is in contact with the corresponding end face 111, the first side surface 112, and the second side surface 113. Preferably, the base layer 121 has excellent adhesion to the outer surface of the element body 11 and the outer surface of the internal electrode 116. For this reason, it is particularly preferred that the base layer 121 is a Cu layer.

[0061] The Ni layer 122 is formed by, for example, plating and is mainly composed of Ni. The Ni layer 122 protects the corresponding base layer 121. The Ni layer 122 covers the corresponding base layer 121 covering the corresponding end surface 111, the first side surface 112, and the second side surface 113. In addition, the Ni layer 122 may extend beyond the corresponding base layer 121 and may contact the first side surface 112 and the second side surface 113 of the element body 11 near the distal end portion 12d.

[0062] The material for the upper metal layer 123 may be a metal, such as Cu, Fe, Zn, Al, Pt, Pd, Ag, Au or Sn, or may be an alloy containing at least one of these metals. The upper metal layer 123 is formed, for example, by plating. The upper metal layer 123 covers the Ni layer 122 and can improve the wettability of the solder that bonds the external electrode 12 of the capacitor 1 to the substrate 2a. For this reason, it is particularly preferred that the upper metal layer 123 is a Sn layer. However, it should be noted that in the electronic component according to the present invention, the upper metal layer 123 is not absolutely necessary.

[0063] In the capacitor 1 according to the present embodiment, the thickness of the Ni layer 122 differs depending on the position in the external electrode 12. More specifically, in the side surface 12b of the external electrode 12, the thickness d1 near the distal portion 12d is different from the thickness d3 near the proximal portion 12c, and the thickness d1 near the distal portion 12d is greater than the thickness d3 near the proximal portion 12c. In addition, the thicknesses d1 and d3 in the side surface 12b are different from the thickness d2 in the end surface side 12a, and the thicknesses d1 and d3 in the side surface 12b are greater than the thickness d2 in the end surface side 12a. In other words, the thickness of the Ni layer 122 is smaller in the end surface side 12a, and the thickest portion of the Ni layer 122 in the side surface 12b exists near the distal portion 12d. Thus, moisture degradation and cracking are reduced. As Figure 2As shown, the thicknesses d1 and d3 are the thicknesses measured from the surface of the Ni layer 122 in contact with the base layer 121 to the opposite surface of the Ni layer 122 in a direction perpendicular to the second side surface 113. Figure 2 As shown, the thickness d2 is a thickness measured from the surface of the Ni layer 122 in contact with the base layer 121 to the opposite surface of the Ni layer 122 in a direction perpendicular to the end surface 111 .

[0064] The term "near distal portion 12d" may be regarded as a region from the middle between distal portion 12d and proximal portion 12c to distal portion 12d. The term "near proximal portion 12c" may be regarded as a region from the middle between distal portion 12d and proximal portion 12c to proximal portion 12c.

[0065] Figure 2 The thicknesses d1 and d3 of the portion of the Ni layer 122 covering the second side surface 113 are shown, while the thicknesses d1 and d3 of the portion of the Ni layer 122 covering the first side surface 112 are shown. Figure 2 The thickness is the same.

[0066] Figure 3 It is a schematic diagram used to describe the causes of cracks.

[0067] As described above, the capacitor 1 is connected to the pad portion 3 on the substrate 2a via the solder 4. The capacitor 1 mounted on the substrate 2a is subjected to a thermal cycle test. In the thermal cycle test, stress is applied to the external electrode 12 due to the difference in thermal expansion between different materials. In addition, if the Ni layer 122 is thick, a large internal stress (residual stress) remains in the external electrode 12.

[0068] The total stress F of the internal stress and the stress caused by the thermal cycle test is concentrated particularly on the distal end portion 12d of the side surface 12b of the external electrode 12. If the stress F exceeds the strength of the dielectric layer 115 of the element body 11, a crack 117 will appear in the element body 11. Such a crack 117 is likely to appear on the second side surface 113 of the element body 11. In particular, the crack 117 caused by the thermal cycle test is likely to appear on the second side surface 113 opposite to the substrate 2a.

[0069] The capacitor 1 mounted on the substrate 2a is also subjected to stress due to the bending of the substrate 2a. The stress due to the bending is applied to the external electrode 12 via the solder 4, and if the total stress F which is a combination of the stress and the internal stress of the external electrode 12 exceeds the strength of the dielectric layer 115 of the element body 11, cracks 117 also appear in the element body 11. The cracks 117 due to the bending are likely to appear on the second side surface 113 on the substrate 2a side.

[0070] As described above, in the capacitor 1 according to the present embodiment, the thickness of the portion of the Ni layer 122 on the end face is reduced, so that the internal stress is also reduced, and the stress F caused by the thermal cycle test and the bending of the substrate 2a is small. As a result, the occurrence of the crack 117 is reduced. In addition, since the thickness of the Ni layer 122 in the side face side 12b is greater than that in the end face side 12a, moisture penetration is prevented at the distal end portion 12d of the side face side 12b, thereby reducing moisture resistance degradation. In particular, as Figure 2 As shown, since the thickness d1 near the distal end portion 12d is greater than the thickness d3 near the proximal end portion 12c, the capacitor 1 has a high effect in preventing moisture from entering the distal end portion and reducing internal stress.

[0071] Next, the specific thickness of the Ni layer 122 will be described.

[0072] Figure 4 is a diagram showing the measured thickness of the Ni layer 122 .

[0073] Figure 4 The graph in shows the measurement results of the sample in which both moisture degradation and cracking were sufficiently reduced.

[0074] The Ni layer 122 formed by plating has a thickness d1 in the range of, for example, 4.2 to 5.3 microns near the distal end portion 12d, a thickness d3 in the range of, for example, 3.0 to 4.2 microns near the proximal end portion 12c, and a thickness d2 in the range of, for example, 2.7 to 3.3 microns in the end surface side 12a.

[0075] As a result of detailed studies by the inventors, it was found that if the thickness of the Ni layer 122 at the thickest portion of the side surface 12b (at Figure 2 In the example, the thickness d1 of the Ni layer 122 near the distal end portion 12d is greater than the thickness d2 of the Ni layer 122 on the end surface side 12a by more than 30%, which sufficiently reduces moisture resistance degradation and cracking.

[0076] If the thickness d2 of the Ni layer 122 in the end surface side 12a is 2.5 to 4.0 micrometers, the capacitor 1 is very effective in reducing the internal stress.

[0077] If the thickness of the thinnest portion of the Ni layer 122 in the side surface 12b is at least 3.0 microns, moisture degradation is effectively reduced. If the thickness of the thickest portion of the Ni layer 122 in the side surface 12b is 3.5 to 5.5 microns, it is effective for reducing moisture degradation and reducing internal stress. The thickness of the thickest portion is preferably at least 20% greater than the thickness of the thinnest portion.

[0078] Manufacturing method

[0079] A method of manufacturing the capacitor 1 including the Ni layer 122 having the above-described thickness distribution is described below.

[0080] Figure 5 is a flowchart showing a method of manufacturing the capacitor 1 according to the first embodiment. Figures 6 to 11 1 is a cross-sectional view showing a method of manufacturing the capacitor 1 according to the first embodiment. However, for illustration, the number of layers of the internal electrodes is not accurate.

[0081] exist Figure 5 In the mixing step (S1), an organic solvent and an organic binder used as a dispersant and a molding aid are added to the dielectric material powder, and the powder is crushed and mixed with the organic solvent and the organic binder to obtain a slurry. The dielectric material powder includes, for example, ceramic powder. The dielectric material powder may also contain one or more additives. The additive may be, for example, an oxide or glass of Mg, Mn, V, Cr, Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Co, Ni, Li, B, Na, K or Si. The organic binder may be, for example, polyvinyl butyral resin or polyvinyl acetal resin. The organic solvent may be, for example, ethanol or toluene.

[0082] Next, in Figure 5 In the slurry applying step (S2), as Figure 6 As shown, a slurry containing ceramic powder is applied to a carrier film in a sheet form and dried to obtain a green sheet 24. The carrier film is, for example, a PET (polyethylene terephthalate) film. The slurry is applied using, for example, a doctor blade method, a die coater method, or a gravure applicator method.

[0083] Next, in Figure 5 In the printing step (S3), as Figure 7 As shown, a conductive paste (which will become an internal electrode) is applied to the green sheets 24A, 24B in a predetermined pattern to form internal electrode patterns 23A, 23B. At this time, a plurality of internal electrode patterns 23A or 23B are formed on a single green sheet 24A or 24B so that the internal electrode patterns 23A or 23B are separated from each other in the longitudinal direction of the green sheet 24A or 24B.

[0084] The conductive paste for the internal electrode includes a metal powder used as a material for the internal electrode 116. For example, if the metal used as the material for the internal electrode 116 is Ni, the conductive paste for the internal electrode includes Ni powder. The conductive paste for the internal electrode also includes a binder, a solvent, and, if necessary, an auxiliary agent. The conductive paste for the internal electrode layer may include a ceramic material having the same main component as the dielectric layer 115 as a common material. The application of the conductive paste for the internal electrode layer may be performed using a screen printing method, an inkjet printing method, or a gravure printing method.

[0085] Next, in Figure 5 In the molding step (S4), as Figure 8 As shown, green sheets 24A, 24B on which internal electrode patterns 23A, 23B are formed and green sheets 25A, 25B serving as outer layers on which internal electrode patterns 23A, 23B are not formed are stacked. The green sheets 24A, 24B, 25A and 25B are stacked in a predetermined order and in a predetermined number to form a laminated block.

[0086] Next, in Figure 5 In the pressing step (S5), the stacked block is pressed so that the green sheets 24A, 24B, 25A and 25B are pressed, as shown in FIG. Fig. 9 The stacked block can be pressurized by, for example, sandwiching the stacked block between resin films and hydrostatically pressurizing the stacked block.

[0087] Next, in Figure 5 In the cutting step (S6), the pressed laminated block is cut so that it is divided into a plurality of component bodies, each of which has a rectangular parallelepiped shape, such as Fig.10 The cutting of the stacked blocks is performed by, for example, blade cutting or the like.

[0088] Next, in Figure 5 In the adhesive removal step (S7), the adhesive contained in each element body is removed by heating. In the adhesive removal step, for example, N is heated at about 350 degrees Celsius. 2 The atmosphere heats the element body.

[0089] Next, in Figure 5 In the sintering step (S8) in the embodiment, the element body is sintered so that the internal electrode 116 and the dielectric layer 115 are integrated. The sintering step of the element body 11 is performed in a sintering furnace, for example, at a temperature range of 1000 degrees Celsius to 1400 degrees Celsius for 10 minutes to 2 hours. If a base metal such as Ni or Cu is used as the material of the internal electrode 116, the sintering step can be performed in the sintering furnace while the inside of the sintering furnace is maintained in a reducing atmosphere to prevent the internal electrode 116 from being oxidized.

[0090] Next, in Figure 5In the base layer forming step (S9), a conductive paste (which will become the base layer) is applied to the two end surfaces 111, the first side surface 112 and the second side surface 113 of the substrate, and then dried. For example, the conductive paste for the base layer is applied using an immersion method. The conductive paste for the base layer includes a powder or filler of a metal used as a conductive material for the base layer 121. For example, if the metal used as the conductive material for the base layer 121 is Cu, the conductive paste for the base layer contains a powder or filler of Cu. The conductive paste for the base layer also contains a glass component as a common material. The conductive paste for the base layer also contains a binder and a solvent. After the conductive paste for the base layer is applied, it is dried and then sintered at 700-900 degrees Celsius to form a Fig.11 The base layer 121 shown in (A).

[0091] Next, in Figure 5 In the pre-plating step (S10), as Fig.11 As shown in (B), the base layer 121 is covered with a mask material 125 except for the distal end portion 12d of the side surface 12b. Then, the base layer 121 is sandblasted at the distal end portion 12d. More specifically, the sandblasting medium M is ejected from the nozzle 6 toward the base layer 121 of the side surface 12b to polish the base layer 121 of the distal end portion 12d. Therefore, the thickness of the base layer 121 at the distal end portion 12d is reduced.

[0092] Before polishing, the surface of the base layer 121 is dotted with glass components, which inhibits the adhesion of the nickel plating, and the glass components are removed from the polished portion of the base layer 121, thereby improving the adhesion of the nickel plating.

[0093] In the sandblasting step, the medium projection pressure, the medium projection amount, the medium type, and the sandblasting time may be adjusted to adjust the processing state of the base layer 121. In addition, the position and range of the mask material 125 may be adjusted to adjust the position of the base layer 121 to be processed. After the sandblasting step, the mask material 125 is removed.

[0094] In the pre-plating step, chemical polishing or physical grinding may be performed instead of sandblasting. In chemical polishing and physical grinding, the position to be processed is also limited by the mask material 125.

[0095] In the case of chemical polishing in the pre-plating step, the type of chemical solution, the concentration of the polishing solution, the stirring speed, and the immersion time can be adjusted to adjust the processing state of the base layer 121. In the case of physical grinding in the pre-plating step, the type of abrasive, the input amount of the element body, the vibration frequency, and the grinding time can be adjusted to adjust the processing state of the base layer 121.

[0096] Next, in Figure 5 In the plating step (S11), as Fig.11As shown in (C), the Ni layer 122 and the upper metal layer 123 are sequentially formed on the base layer 121 by plating, thereby obtaining the capacitor 1. In the plating step, for example, the element body provided with the base layer 121 is placed in a drum together with a plating solution, and the drum is rotated and energized to form the Ni layer 122 or the upper metal layer 123.

[0097] As described above, since the adhesion of the Ni plating layer is improved at the polished position in the pre-plating step (S10), the thickness of the Ni layer 122 at this position is greater than the thickness at other positions where polishing is blocked by the mask material 125. In addition, in the position covered by the mask material 125, the Ni layer 122 in the side surface side 12b is thicker than the Ni layer 122 in the end surface side 12a. As a result, the above reference is obtained. Figure 2 and Figure 3 Describe the relationship between thicknesses d1, d2 and d3.

[0098] Fig.12 is a diagram showing the difference in thickness of the base layer (Cu layer) 121 with and without the sandblasting process.

[0099] In the portion having a surface that has not been sandblasted (non-sandblasted surface), such as the end surface side 12a, the thickness of the base layer (Cu layer) 121 is centered around about 13 microns and is in the range of 12.3 to 13.5 microns. In contrast, in the portion having a surface that has been sandblasted (sandblasted surface), the thickness of the base layer (Cu layer) 121 is centered around about 11.7 microns and is in the range of 11.0 to 12.3 microns. In order to increase the thickness of the Ni layer 122 at the position where the base layer 121 is polished, it is preferred to reduce the thickness of the base layer 121 by 10% or more by polishing.

[0100] Fig.13 is a graph showing the difference in thickness of the Ni layer 122 with and without the sandblasting process.

[0101] Fig.13 The thickness of the Ni layer 122 in the distal portion 12d and the proximal portion 12c of the side surface 12b is shown when the surface of the Ni layer 122 is sandblasted (sandblasted surface) and when the surface of the Ni layer 122 is not sandblasted (non-sandblasted surface).

[0102] The thickness of the Ni layer 122 is 3.1 to 3.3 μm on the unblasted surface of the proximal portion 12c, and 4.2 to 4.4 μm on the blasted surface of the proximal portion 12c. The thickness of the Ni layer 122 is 3.7 to 4.0 μm on the unblasted surface of the distal portion 12d, and 4.6 to 5.0 μm on the blasted surface of the distal portion 12d.

[0103] On both the blasted surface and the unblasted surface, the Ni layer 122 in the distal portion 12d is about 10% thicker than that in the proximal portion 12c. In addition, in the distal portion 12d and the proximal portion 12c, the thickness of the Ni layer 122 on the blasted surface is about 20% thicker than that on the unblasted surface.

[0104] Therefore, by forming an unblasted surface in the proximal portion 12c and a blasted surface in the distal portion 12d using the mask material 125, the thickness of the Ni layer 122 in the distal portion 12d (thickest portion) of the side surface 12b can be at least 30% greater than the thickness in the proximal portion 12c. Such a large difference in the thickness of the Ni layer 122 in the distal portion 12d and the proximal portion 12c helps to significantly reduce moisture-resistant degradation and cracking.

[0105] Second embodiment

[0106] Next, electronic components according to other embodiments different from the first embodiment will be described. Except for the thicker portion in the Ni layer 122, the electronic components according to the second to fifth embodiments are the same as the capacitor according to the first embodiment, so the following description will focus on the differences and omit repeated explanations.

[0107] Fig.14 A cross-sectional view of a capacitor according to a second embodiment is shown. Fig.14 (A) is along Figure 1 The cross-sectional view taken along line AA in Fig.14 (B) is along Figure 1 Cross-sectional view taken along line BB in FIG.

[0108] In the first embodiment, the Ni layer 122 has a thickness distribution common to all four side surfaces 12b covering the pair of first side surfaces 112 and the pair of second side surfaces 113. In contrast, in the capacitor 101 according to the second embodiment, the Ni layer 122 has a thickness distribution common to all four side surfaces 12b covering the pair of first side surfaces 112 and the pair of second side surfaces 113. Fig.14 The side surface 12b of the second side surface 113 located at the lower part (which will face the substrate 2a after the capacitor 101 is mounted on the substrate 2a) has a greater thickness. Fig.14 The other second side surface 113 located at the upper part and the other side surface 12b of the first side surface 112 have a smaller thickness. The thickness of the Ni layer 122 in the side surface 12b on the upper second side surface 113 and the first side surface 112 is the same as the thickness of the Ni layer 122 in the end surface side 12a.

[0109] In other words, in the second embodiment, among the four side surfaces 12b of the external electrode 12 surrounding the element body 11, the Ni layer 122 has a larger thickness in the side surface 12b facing the substrate 2a, and a smaller thickness in the other three side surfaces 12b. Cracks caused by bending stress are likely to occur on the second side surface 113 facing the substrate 2a. Accordingly, in the case where bending stress becomes a particular problem due to factors such as the size of the capacitor 101, the structure according to the second embodiment will reduce cracking.

[0110] Third embodiment

[0111] Next, an electronic component (capacitor) according to a third embodiment will be described.

[0112] Fig.15 A cross-sectional view of a capacitor according to a third embodiment is shown. Fig.15 (A) is along Figure 1 The cross-sectional view taken along line AA in Fig.15 (B) is along Figure 1 Cross-sectional view taken along line BB in FIG.

[0113] Compared with the capacitor 101 according to the second embodiment, in the capacitor 102 according to the third embodiment, the covering Fig.15 The thickness of the Ni layer 122 in the side surface side 12b of the second side surface 113 located at the lower part (which will face the substrate 2a after the capacitor 101 is mounted on the substrate 2a) is the same as the thickness of the Ni layer 122 in the end surface side 12a. Fig.15 The other second side surface 113 located at the upper portion and the other side surface 12b of the first side surface 112 have a greater thickness.

[0114] In other words, in the third embodiment, the Ni layer 122 has a smaller thickness in the side surface 12b facing the substrate 2a, and has a larger thickness in the other three side surfaces 12b, among the four side surfaces 12b of the external electrode 12 surrounding the element body 11. Cracks caused by thermal cycles are likely to occur on the second side surface 113 opposite to the substrate 2a. Therefore, in the case where thermal cycle cracks become a particular problem due to factors such as the size of the capacitor 102, the structure according to the third embodiment will reduce cracks.

[0115] Fourth embodiment

[0116] Next, an electronic component (capacitor) according to a fourth embodiment will be described.

[0117] Fig.16 is a cross-sectional view of a capacitor according to a fourth embodiment. Fig.16 Shown along Figure 1 Cross-sectional view taken along line AA.

[0118] In the capacitor 103 according to the fourth embodiment, each Ni layer 122 of the external electrode 12 has the thickest portion on the side surface, particularly in the middle between the distal portion 12d and the proximal portion 12c. In the case where the thickest portion is located between the distal portion 12d and the proximal portion 12c, moisture resistance degradation and cracking can also be reduced.

[0119] Fifth embodiment

[0120] Next, an electronic component (capacitor) according to a fifth embodiment will be described.

[0121] Fig.17 is a cross-sectional view of a capacitor according to a fifth embodiment. Fig.17 Shown along Figure 1 Cross-sectional view taken along line BB in FIG.

[0122] In the capacitor 104 according to the fifth embodiment, each Ni layer 122 of the external electrode 12 has the thickest portion in the side surface 12b, particularly at the boundary (edge ​​line) between the first side surface 112 and the second side surface 113. In the case where the thickest portion of the Ni layer 122 is located on the edge line, moisture resistance degradation and cracking can also be reduced.

[0123] Sixth Embodiment

[0124] Next, an electronic component according to a sixth embodiment will be described. The electronic component according to the sixth embodiment is, for example, a chip inductor.

[0125] Fig.18 A cross-sectional view showing a structural example of a chip inductor according to a sixth embodiment. Fig.18 (A) shows a cross-sectional view of the XY plane, Fig.18 (B) shows a cross-sectional view of the XZ plane.

[0126] The chip inductor 200 includes an element body 13 and external electrodes 12 .

[0127] The element body 13 has end faces 131 at both ends in the length direction X, and the pair of end faces 131 are arranged opposite to each other. The element body 13 has first side faces 132 at both ends in the width direction Y, and second side faces 133 at both ends in the height direction Z.

[0128] Each of the first side surface 132 and the second side surface 133 is a surface connected to the end surface 131 and extending from one of the end surfaces 131 to the other of the end surfaces 131. Each second side surface 133 is a surface connected to two first side surfaces 132 and two end surfaces 131.

[0129] The element body 13 has a magnetic body 135 and an inner conductor 136 wound in a coil shape. The magnetic body 135 is made of, for example, ferrite.

[0130] The material for the internal conductor 136 may be a metal such as Cu, Fe, Zn, Al, Ni, Pt, Pd, Ag, Au, or Sn, or may be an alloy containing at least one of these metals. The internal conductor 136 reaches the end surface 131 of the element body 13, and both ends of the internal conductor 136 are connected to a pair of external electrodes 12, respectively.

[0131] A pair of external electrodes 12 are formed on the longitudinal ends of the element body 11 so as to be separated from each other in the length direction X. Each external electrode 12 is formed to cover the corresponding end surface 131 of the element body 13 , the adjacent portion of the first side surface 132 , and the adjacent portion of the second side surface 133 .

[0132] Each of the external electrodes 12 includes a base layer 121 , a Ni layer 122 , and an upper metal layer 123 .

[0133] In the side surface 12b of the external electrode 12, the thickness d1 near the distal end portion 12d is different from the thickness d3 near the proximal end portion 12c, and the thickness d1 near the distal end portion 12d is greater than the thickness d3 near the proximal end portion 12c. In addition, the thicknesses d1 and d2 in the side surface 12b are different from the thickness d2 in the end surface side 12a, and the thicknesses d1 and d2 in the side surface 12b are greater than the thickness d2 in the end surface side 12a. In other words, the thickness of the Ni layer 122 is smaller in the end surface side 12a, and the thickest part of the Ni layer 122 in the side surface 12b exists near the distal end portion 12d. Therefore, moisture-resistant degradation and cracking are reduced.

[0134] Reference Symbols

[0135] 1. 101, 102, 103, 104: Capacitors

[0136] 2a: Substrate

[0137] 2: Circuit board layout

[0138] 3: Pad part

[0139] 4: Solder

[0140] 11: Component body

[0141] 111: End face

[0142] 112: First side

[0143] 113: Second side

[0144] 115: Dielectric layer

[0145] 116: Internal electrode

[0146] 12: External electrode

[0147] 12a: End face side

[0148] 12b: Sideways

[0149] 12c: Proximal part

[0150] 12d: Distal part

[0151] 121: Grassroots

[0152] 122: Ni layer

[0153] 123: Upper metal layer

[0154] 13: Component body

[0155] 131: End face

[0156] 132: First side

[0157] 133: Second side

[0158] 135: Magnetic body

[0159] 136: Inner conductor

[0160] 200: Chip Inductor

Claims

1. An electronic component, comprising: a component body having a profile with a pair of end faces and a plurality of side faces, each side face being connected to the end faces and extending from one end face to the other end face, and the component body having at least one conductor located within the component body; a base layer, each base layer being in contact with one of the side faces and one of the end faces; and a Ni layer formed on each of the base layers, each Ni layer being disposed on the side faces and the corresponding end faces, each Ni layer having at least one thickest portion disposed on at least one side face, the thickness of the thickest portion being at least 30% greater than the thickness of the portion of the Ni layer disposed on the corresponding end face.

2. The electronic component according to claim 1, wherein each base layer is a Cu layer.

3. The electronic component according to claim 2, further comprising an upper metal layer formed on each of the Ni layers.

4. The electronic component according to claim 3, wherein each base layer is a Cu layer, and each upper metal layer is a Sn layer.

5. The electronic component according to claim 1, wherein the thickness of the thickest portion is at least 20% greater than the thickness of at least one thinnest portion disposed on at least one side face.

6. The electronic component according to claim 1, wherein each Ni layer has the thickest portion located on the side face and being farther from the corresponding end face than the middle between the edge farthest from the corresponding end face and the edge closest to the corresponding end face.

7. The electronic component according to claim 1, wherein the base has a first side face connected to the end face and second side faces each connected to the first side face and the end face, and wherein each Ni layer has the thickest portion disposed at the boundary between the first side face and the second side faces.

8. The electronic component according to claim 1, wherein the thickness of the thickest portion of each Ni layer is 3.5 to 5.5 micrometers.

9. The electronic component according to claim 1, wherein the thickness of the portion of each Ni layer disposed on the corresponding end face is 2.5 to 4.0 micrometers.

10. The electronic component according to claim 5, wherein the thickness of the thinnest portion of each Ni layer is at least 3.0 micrometers.

11. The electronic component according to claim 6, wherein the thickness of the thickest portion of each Ni layer is at least 30% greater than the thickness of the portion of the Ni layer disposed at the boundary between the end face and each side face.

12. A circuit board arrangement, comprising: the electronic component according to any one of claims 1 to 11; and a substrate on which the electronic component is mounted via solder.

13. An electronic device comprising the circuit board arrangement according to claim 12.

14. A method for manufacturing an electronic component, the method comprising: forming a base layer on a component body, the component body having a profile having a pair of end faces and a plurality of side faces, each side face being connected to the end faces and extending from one end face to the other end face, and the component body having at least one conductor located within the component body, wherein each base layer is in contact with one of the side faces and the end faces; reducing the thickness of at least a portion of each base layer, the portion being in contact with at least one side surface; Ni layers are respectively formed on the base layer, wherein each Ni layer is arranged on the side surface and the corresponding end surface.

15. The method for manufacturing an electronic component according to claim 14, in, The step of reducing the thickness is performed by sandblasting.

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