Coil components

Abstract

The present invention provides a coil component that can help improve reliability. The first substrate (11) has recessed portions (15a) to (15d) arranged at the corners of the bottom surface (11a). The external electrodes (14a) to (14d) have an electrode body portion (51) on the bottom surface (11a) that is respectively arranged around the recessed portions (15a) to (15d). The electrode body portion (51) is formed by stacking a plurality of metal layers, and the first metal layer (61) located at the innermost side of the plurality of metal layers is formed on the bottom surface (11a) at a position separated from the short side ridgeline portion (71) between the bottom surface (11a) and the side surface.

Description

Technical Field

[0001] The present disclosure relates to coil components. Background Art

[0002] In the past, electronic components were mounted on various electronic devices. As one of the electronic components, for example, a laminated coil component is known (for example, refer to Patent Document 1). In the coil component of Patent Document 1, external electrodes are provided at the four corners of the bottom surface of the substrate. The external electrodes are composed of a plurality of metal layers. In addition, in the coil component of Patent Document 1, rolling is performed to chamfer the ridgeline of the substrate, etc.

[0003] Patent Document 1: International Publication No. 2013-031880

[0004] However, in the coil component as described above, if chamfering is performed by rolling or the like, the surface layer of the external electrode may extend out of the bottom surface of the substrate during the implementation. In this way, if there is an extension of the external electrode, stress is likely to be concentrated on this part, and when a high-temperature treatment based on mounting reflow soldering is performed, the substrate may be broken and the electrode may be cracked. In this way, there is still room for improvement in terms of reliability. Summary of the invention

[0005] An object of the present disclosure is to provide a coil component that can contribute to improvement in reliability.

[0006] A coil component as one embodiment of the present disclosure includes: a magnetic substrate having a rectangular bottom surface including long sides and short sides, an upper surface located on the opposite side of the bottom surface, and a side surface on the long side and a side surface on the short side connecting the bottom surface and the upper surface; a laminate having an insulating layer formed on the upper surface and a coil formed in the insulating layer; and an external electrode provided on the bottom surface, the magnetic substrate having a recessed portion provided at a corner of the bottom surface, the external electrode having an electrode main body, the electrode main body being provided around the recessed portion on the bottom surface, the electrode main body being formed by stacking a plurality of metal layers, the electrode main body having a base layer, the base layer being the innermost metal layer in the stacking direction of the laminate, the base layer being formed on the bottom surface at a position separated from the short side ridgeline between the bottom surface and the side surface on the short side. Here, "innermost" refers to the position closest to the magnetic substrate among the stacked plurality of metal layers.

[0007] According to this structure, the base layer is formed on the bottom surface at a position separated from the short side edge line portion between the bottom surface and the side surface, so that the base layer can be prevented from extending along the short side edge line portion due to rolling or the like. By preventing the base layer from extending along the short side edge line portion, stress concentration at this portion can be suppressed. Therefore, the rupture of the substrate around this portion and the generation of cracks in the external electrode can be suppressed.

[0008] The coil component according to the present invention can contribute to improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view of a coil component in one embodiment.

[0010] Figure 2 It is an exploded perspective view of the coil component in this embodiment.

[0011] Figure 3 It is a cross-sectional view for explaining the structure of the external electrode of the coil component in this embodiment.

[0012] Figure 4 It is a top view for explaining the first metal layer of the external electrode of the coil component in this embodiment.

[0013] Figure 5 It is a top view for explaining the second metal layer of the external electrode of the coil component in this embodiment.

[0014] Figure 6 It is a top view for explaining the third metal layer of the external electrode of the coil component in this embodiment.

[0015] Figure 7 It is a plan view for explaining the fourth metal layer and the fifth metal layer of the external electrode of the coil component in this embodiment.

[0016] Figure 8 It is an explanatory diagram for explaining the stacked structure of the external electrodes of the coil component in this embodiment.

[0017] Fig. 9 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0018] Fig.10 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0019] Fig.11 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0020] Fig.12 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0021] Fig.13 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0022] Fig.14 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0023] Fig.15 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0024] Fig.16 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0025] Fig.17 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0026] Fig.18 It is an explanatory diagram for explaining the method for manufacturing the coil component in this embodiment.

[0027] Description of Reference Numerals

[0028] 10…coil component; 11…first substrate (magnetic substrate); 11a…bottom surface (bottom surface); 12…second substrate (magnetic layer); 13…laminate; 14a, 14b, 14c, 14d…external electrodes; 15a, 15b, 15c, 15d…recess; 21a, 21b, 21c…insulating layer; 22a, 22b…coil; 51…electrode body; 51a…distal end; 52…connecting portion; 61…first metal layer (base layer); 62…second metal layer (low resistance layer); 63…third metal layer (low resistance layer); 63a…distal end; 64…fourth metal layer (film layer); 65…fifth metal layer; 71…short side ridge; 74…recess ridge; L1, L2…distance. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments will be described with reference to the drawings.

[0030] In addition, the drawings may show components in an enlarged manner for easy understanding. Also, the dimensional ratios of components may differ from the actual ones or from those in other drawings.

[0031] like Figure 1 As shown in FIG. 1 , the coil component 10 is in a rectangular parallelepiped shape. The coil component 10 includes a first substrate 11 , a second substrate 12 , a laminate 13 , and external electrodes 14 a , 14 b , 14 c , and 14 d . The first substrate 11 and the second substrate 12 are laminated to sandwich the laminate 13 .

[0032] exist Figure 1 In the coil component 10, the stacking direction D of the first substrate 11, the stacked body 13, and the second substrate 12 is set as the Z-axis direction, and when viewed from the Z-axis direction, the direction in which the long side of the coil component 10 extends is set as the X-axis direction, and the direction in which the short side of the coil component 10 extends is set as the Y-axis direction. In addition, with respect to the Z-axis direction, the side where the external electrodes 14a to 14d of the coil component 10 exist is set as the bottom, and the opposite side is set as the top.

[0033] like Figure 1 as well as Figure 2 As shown, the first substrate 11 is plate-shaped. The first substrate 11 has a rectangular bottom surface 11a and an upper surface 11b located on the opposite side of the bottom surface 11a. The upper surface 11b faces the stacked body 13 side in the Z-axis direction, and the bottom surface 11a faces the side opposite to the stacked body 13 in the Z-axis direction.

[0034] like Figure 1 As shown, the first substrate 11 has two side surfaces 11c and 11d connecting the bottom surface 11a and the upper surface 11b and facing the X-axis direction, and two side surfaces 11e and 11f connecting the bottom surface 11a and the upper surface 11b and facing the Y-axis direction. The two side surfaces 11c and 11d facing the X-axis direction face opposite sides. The two side surfaces 11e and 11f facing the Y-axis direction face opposite sides. In addition, the first substrate 11 has a short side ridgeline portion 71 between the bottom surface 11a and the side surfaces 11c and 11d, and a long side ridgeline portion 72 between the bottom surface 11a and the side surfaces 11e and 11f.

[0035] Here, in this specification, "rectangular shape" includes a shape in which at least one of the four corners of the rectangle has a notch. That is, in the bottom surface 11a, which becomes the bottom surface, a shape in which the four corners obtained by extending the short side edge line portion 71 and the long side edge line portion 72 are cut into arc shapes toward the center of the bottom surface 11a is also included in the rectangular shape. Moreover, the shape of the first substrate 11 can be called a cuboid having the bottom surface 11a of this "rectangular shape".

[0036] Furthermore, the first substrate 11 has recessed portions 15a, 15b, 15c, and 15d whose four corners are recessed toward the center of the first substrate 11 when viewed from a direction perpendicular to the bottom surface 11a. That is, each of the recessed portions 15a, 15b, 15c, and 15d forms an arc-shaped connecting ridgeline portion 73 on the bottom surface 11a, and the diameter of the arc is gradually reduced as it approaches the upper surface 11b.

[0037] The first substrate 11 is a magnetic substrate. An example of a magnetic substrate is a sintered body of ferrite. In addition, the first substrate 11 may also be a molded body of a resin containing magnetic powder. The magnetic powder is, for example, ferrite or a metal magnetic material such as iron (Fe), silicon (Si), chromium (Cr), and the resin material is, for example, an epoxy-based resin material. In the case where the first substrate 11 is a resin containing magnetic powder, it is preferred to mix two or three magnetic powders having different particle size distributions, because it is easy to appropriately disperse the magnetic powder in the resin.

[0038] like Figure 2 As shown, the laminate 13 includes a plurality of insulating layers 21a to 21c, coils 22a, 22b, and an adhesive layer 23 laminated on the upper surface 11b of the first substrate 11. The direction of the laminated insulating layers 21a to 21c, coils 22a, 22b, and adhesive layer 23 of the laminate 13 is consistent with the lamination direction D and the Z-axis direction. In addition, the laminate 13 sometimes does not have interfaces between the layers of the insulating layers 21a to 21c or other interfaces.

[0039] like Figure 2 As shown, the insulating layers 21a to 21c are stacked in the order of the insulating layer 21a, the insulating layer 21b, and the insulating layer 21c starting from the first substrate 11 side in the Z-axis direction. In addition, the insulating layers 21a to 21c have the same size as the upper surface 11b of the first substrate 11. The insulating layer 21a has cutouts C1a to C1d at the four corners. The insulating layer 21b has cutouts C2a to C2d at the four corners. The insulating layer 21b has a through hole H1 that passes through in the Z-axis direction. Among the four corners of the insulating layer 21c, the two ends on one side in the Y-axis direction have cutouts C3b and C3d. The insulating layer 21c has through holes H2 and H3 that pass through in the Z-axis direction.

[0040] The cutouts C1a and C2a are provided at positions overlapping with the external electrode 14a in the Z-axis direction. The cutouts C1b, C2b, and C3b are provided at positions overlapping with the external electrode 14b in the Z-axis direction. The cutouts C1c and C2c are provided at positions overlapping with the external electrode 14c in the Z-axis direction. The cutouts C1d, C2d, and C3d are provided at positions overlapping with the external electrode 14d in the Z-axis direction.

[0041] Various resin materials such as polyimide resin, epoxy resin, phenol resin, and benzocyclobutene resin can be used for the insulating layers 21 a to 21 c.

[0042] The coil 22 a includes a coil conductor 31 and lead portions 32 , 33 , 34 , 35 , 36 , and 37 .

[0043] The coil conductor 31 is disposed between the insulating layer 21a and the insulating layer 21b, and is in a planar spiral shape that rotates clockwise and approaches the center when viewed from above in the Z-axis direction. The center of the coil conductor 31 coincides with the center of the coil component 10 when viewed from above in the Z-axis direction.

[0044] The lead portion 32 is connected to the outer end of the coil conductor 31. In addition, the lead portion 32 is led to the cutout portion C1c of the insulating layer 21a. The lead portion 32 passes through the insulating layer 21a in the Z-axis direction via the cutout portion C1c. The lead portion 32 is led to the cutout portion C2c of the insulating layer 21b and connected to the lead portion 33 provided in the cutout portion C2c.

[0045] The lead portion 32 configured as described above is connected to the end of the coil conductor 31 and is led out to the cutout portion C1c of the insulating layer 21a constituting the laminate 13. Thus, the lead portion 32 is exposed in the recess 15c when viewed from below in the Z-axis direction.

[0046] The lead portion 34 penetrates the insulating layer 21 b in the Z-axis direction via the through hole H1 , and is connected to the inner end portion of the coil conductor 31 .

[0047] The first end of the lead portion 35 passes through the insulating layer 21c in the Z-axis direction via the through hole H3 to be connected to the lead portion 34. The second end of the lead portion 35 is led to the cutout portion C3d of the insulating layer 21c. The lead portion 35 passes through the insulating layer 21c in the Z-axis direction via the cutout portion C3d.

[0048] The lead portion 36 is provided in the cutout portion C2d of the insulating layer 21b. Thus, the lead portion 36 is connected to the second end side of the lead portion 35. The lead portion 36 penetrates the insulating layer 21b in the Z-axis direction via the cutout portion C2d.

[0049] The lead portion 37 is provided in the cutout portion C1d of the insulating layer 21a. Thus, the lead portion 37 is connected to the lead portion 36. The lead portion 37 penetrates the insulating layer 21a in the Z-axis direction via the cutout portion C1d.

[0050] The lead portions 34 to 37 configured as described above are connected to the ends of the coil conductor 31 and are led out to the cutout portion C1d of the insulating layer 21a constituting the laminate 13. Thus, the lead portion 37 is exposed in the recess 15d when viewed from below in the Z-axis direction.

[0051] The coil 22 b includes a coil conductor 41 and lead portions 42 , 43 , 44 , 45 , and 46 .

[0052] The coil conductor 41 is disposed between the insulating layer 21b and the insulating layer 21c, and when viewed from the upper side in the Z-axis direction, it is in a planar spiral shape that rotates clockwise while approaching the center. That is, the coil conductor 41 rotates in the same direction as the coil conductor 31. The center of the coil conductor 41 coincides with the center of the coil component 10 when viewed from the Z-axis direction. Therefore, the coil conductor 41 overlaps with the coil conductor 31 when viewed from the Z-axis direction.

[0053] The lead portion 42 is connected to the outer end of the coil conductor 41. The lead portion 42 is led out to the cutout portion C2a of the insulating layer 21b. The lead portion 42 penetrates the insulating layer 21b in the Z-axis direction via the cutout portion C2a.

[0054] The lead portion 43 is provided in the cutout portion C1a of the insulating layer 21a, so that the lead portion 43 is connected to the lead portion 42. The lead portion 43 penetrates the insulating layer 21a in the Z-axis direction via the cutout portion C1a.

[0055] The lead portions 42 and 43 configured as described above are connected to the ends of the coil conductor 41 and are led out to the cutout portion C1a. Thus, the lead portion 43 is exposed in the recess 15a when viewed from below in the Z-axis direction.

[0056] The first end side of the lead portion 44 passes through the insulating layer 21c in the Z-axis direction via the through hole H2, thereby connecting to the inner end of the coil conductor 41. The second end side of the lead portion 44 is led to the cutout portion C3b of the insulating layer 21c. The lead portion 44 passes through the insulating layer 21c in the Z-axis direction via the cutout portion C3b.

[0057] The lead portion 45 is provided in the cutout portion C2b of the insulating layer 21b, so that the lead portion 45 is connected to the lead portion 44. The lead portion 45 penetrates the insulating layer 21b in the Z-axis direction via the cutout portion C2b.

[0058] The lead portion 46 is provided in the cutout portion C1b of the insulating layer 21a. Thus, the lead portion 46 is connected to the lead portion 45. The lead portion 46 penetrates the insulating layer 21a in the Z-axis direction via the cutout portion C1b.

[0059] The lead portions 44 to 46 configured as described above are connected to the end of the coil conductor 41 via the lead portion 44, and are led out to the cutout portion C1b via the lead portion 46 connected to the lead portion 44 via the lead portion 45. Thus, the lead portion 46 is exposed in the recess 15b when viewed from the lower side toward the upper side in the Z-axis direction.

[0060] The second substrate 12 is in a plate shape. The second substrate 12 has a bottom surface 12a and an upper surface 12b facing the opposite side of the bottom surface 12a. The bottom surface 12a faces the stack 13 side in the Z-axis direction, and the upper surface 12b faces the opposite side of the stack 13 in the Z-axis direction. The second substrate 12 is, for example, a magnetic substrate as an example of a magnetic layer. The second substrate 12 is, for example, composed of the material exemplified in the first substrate 11. The second substrate 12 is bonded to the upper surface of the stack 13 via an adhesive layer 23. As the adhesive layer 23, for example, a thermosetting polyimide resin can be used. In addition, the second substrate 12 can also be composed of a magnetic layer other than a magnetic substrate.

[0061] Each of the external electrodes 14a, 14b, 14c, and 14d includes an electrode main body portion 51 and a connection portion 52 that connects the electrode main body portion 51 and the coils 22a and 22b.

[0062] The electrode body 51 of each external electrode 14a, 14b, 14c, 14d is formed on the bottom surface 11a (bottom surface) of the first substrate 11, around each recessed portion 15a to 15d. More specifically, the electrode body 51 of the external electrode 14a is formed around the recessed portion 15a. The electrode body 51 of the external electrode 14b is formed around the recessed portion 15b. The electrode body 51 of the external electrode 14c is formed around the recessed portion 15c. The electrode body 51 of the external electrode 14d is formed around the recessed portion 15d.

[0063] The connection portion 52 of each external electrode 14a, 14b, 14c, 14d is formed in each recessed portion 15a to 15d of the first substrate 11. More specifically, the connection portion 52 of the external electrode 14a is formed in the recessed portion 15a. The connection portion 52 of the external electrode 14b is formed in the recessed portion 15b. The connection portion 52 of the external electrode 14c is formed in the recessed portion 15c. The connection portion 52 of the external electrode 14d is formed in the recessed portion 15d.

[0064] The external electrodes 14a, 14b, 14c, and 14d are formed at four corners of the bottom surface 11a of the first substrate 11. The external electrodes 14a, 14b, 14c, and 14d are connected to a land pattern of a mounting substrate on which the coil component 10 is mounted by solder or the like.

[0065] Each external electrode 14a, 14b, 14c, 14d is configured to be rectangular when the upper side is viewed from the lower side in the Z-axis direction. The short side direction of the external electrodes 14a, 14b, 14c, 14d is consistent with the short side direction of the bottom surface 11a of the first substrate 11. In addition, the long side direction of the external electrodes 14a, 14b, 14c, 14d is consistent with the long side direction of the bottom surface 11a of the first substrate 11. Here, it also includes the case where each side of the external electrodes 14a, 14b, 14c, 14d is a straight line, and the case where each side is slightly curved. In addition, it can also be a structure in which the long side direction of the external electrodes 14a, 14b, 14c, 14d is inconsistent with the long side direction of the bottom surface 11a. In addition, it can also be a structure in which the short side direction of the external electrodes 14a, 14b, 14c, 14d is inconsistent with the short side direction of the bottom surface 11a.

[0066] Each of the external electrodes 14 a , 14 b , 14 c , and 14 d is formed by laminating a plurality of metal layers.

[0067] like Figure 3 As shown, the plurality of metal layers include a first metal layer 61, a second metal layer 62, a third metal layer 63, a fourth metal layer 64, and a fifth metal layer 65. Here, the connection portion 52 of each external electrode 14a, 14b, 14c, 14d has the same stacked structure as the electrode main body 51 of each external electrode 14a, 14b, 14c, 14d. That is, when the electrode main body 51 includes the first metal layer 61, the second metal layer 62, the third metal layer 63, the fourth metal layer 64, and the fifth metal layer 65, the connection portion 52 also includes the first metal layer 61, the second metal layer 62, the third metal layer 63, the fourth metal layer 64, and the fifth metal layer 65.

[0068] The first metal layer 61 is provided on the bottom surface 11a of the first substrate 11. The first metal layer 61 is located innermost in the Z-axis direction among the metal layers 61 to 65. That is, the first metal layer 61 is equivalent to the base layer. The first metal layer 61 is a metal thin film mainly composed of titanium (Ti). The first metal layer 61 is formed, for example, by sputtering. The first metal layer 61 has a thickness of, for example, not less than 100 nm and not more than 200 nm.

[0069] like Figure 4 As shown, the first metal layer 61 of the electrode body 51 is formed at a position separated from the short-side edge line 71 of the first substrate 11. At this time, the first metal layer 61 of the electrode body 51 is formed at a position in contact with the long-side edge line 72 of the first substrate 11.

[0070] The second metal layer 62 is provided on the first metal layer 61. The second metal layer 62 is composed of a material having a lower resistance than the first metal layer 61. More specifically, the second metal layer 62 is a metal thin film having copper (Cu) as a main component. The second metal layer 62 is formed, for example, by sputtering. The second metal layer 62 has a thickness of, for example, 100 nm or more and 200 nm or less.

[0071] like Figure 5 As shown, the second metal layer 62 of the electrode body 51 is formed at a position of the first substrate 11 that is separated from the short side edge line portion 71. At this time, the second metal layer 62 of the electrode body 51 is formed at a position of the first substrate 11 that is in contact with the long side edge line portion 72. In addition, the second metal layer 62 of the electrode body 51 is equivalent to a low resistance layer.

[0072] The third metal layer 63 is provided on the second metal layer 62. The third metal layer 63 is made of a material having a lower resistance than the first metal layer 61. More specifically, the third metal layer 63 is a metal film having copper (Cu) as a main component. The third metal layer 63 is formed, for example, by electroplating. The third metal layer 63 has a thickness of, for example, about 10 μm.

[0073] like Figure 6 As shown, the third metal layer 63 of the electrode body 51 is formed at a position of the first substrate 11 that is separated from the short side edge line portion 71. At this time, the third metal layer 63 of the electrode body 51 is formed at a position of the first substrate 11 that is in contact with the long side edge line portion 72. In addition, the third metal layer 63 of the electrode body 51 is equivalent to a low resistance layer.

[0074] like Figure 6 As shown, the third metal layer 63 of the connection portion 52 is formed to cover the entire connection portion 52. At this time, the third metal layer 63 is formed to overlap with the concave portion ridgeline portion 74 of the concave portions 15a to 15d that are continuous in the direction from the short side ridgeline portion 71 toward the upper surface 11b. In addition, the third metal layer 63 is formed to overlap with the ridgeline portion 75 of the concave portions 15a to 15d that are continuous in the direction from the long side ridgeline portion 72 toward the upper surface 11b.

[0075] Figure 7The fourth metal layer 64 shown is arranged on the third metal layer 63. The fourth metal layer 64 is a metal film with nickel (Ni) as the main component. The fourth metal layer 64 is formed, for example, by electroplating. The fourth metal layer 64 has a thickness of about 3μm, for example. The length of the fourth metal layer 64 in the short side direction is 72μm, and the dimensional tolerance is 10μm. The extension of the fourth metal layer 64 along the short side edge line portion 71 of the bottom surface 11a is less than 11μm. More preferably, it is less than 5μm. The fourth metal layer 64 is equivalent to a coating layer arranged on the third metal layer 63 constituting the low resistance layer. Here, the coating layer covers and protects the third metal layer 63 constituting the low resistance layer. That is, the fourth metal layer 64 is composed of nickel, so that the so-called copper corrosion in the third metal layer 63 can be suppressed.

[0076] Figure 7 The fifth metal layer 65 shown is provided on the fourth metal layer 64. The fifth metal layer 65 is a metal film having tin (Sn) as a main component. The fifth metal layer 65 is formed, for example, by electroplating. The fifth metal layer 65 has a thickness of about 3 μm, for example. The length of the short side direction of the fifth metal layer 65 is 75 μm, and the dimensional tolerance is 10 μm. It is preferred that the extension of the fifth metal layer 65 along the short side edge line portion 71 of the bottom surface 11a is 13 μm or less.

[0077] When the coil component 10 constructed as described above is a laminate formed by laminating the first substrate 11, the laminate 13, and the second substrate 12, the length of the laminate in the lamination direction D (Z-axis direction) is 0.23 mm, the length in the Y-axis direction as the short side direction in the direction orthogonal to the lamination direction D is 0.3 mm, and the length in the X-axis direction as the long side direction in the direction orthogonal to the lamination direction D is 0.45 mm. In addition, the tolerance of the lengths in the three axial directions is ±0.02 mm.

[0078] like Figure 8 As shown, in the electrode main body 51 adjacent to the recess 15c along the short side of the bottom surface 11a, when the end of the position away from the recess 15c along the short side is set as the distal end 51a, the distance L1 between the recess 15c and the distal end 51a along the short side is preferably 25μm or less. In detail, the distance L1 from the recess 15c to the distal end 63a of the third metal layer 63 in the electrode main body 51 is preferably 25μm or less. In addition, the description is made with an eye on the recess 15c and the electrode main body 51 around the recess 15c, but it is also preferable to set the distance L1 as described above in the electrode main body 51 around the other recesses 15a, 15b, 15d and other recesses 15a, 15b, 15d.

[0079] Figure 8The distance L2 from the short side edge line 71 to the electrode body 51 in the long side direction of the bottom surface 11a shown in FIG. 1 is preferably not less than 3.3 μm and not more than 16.7 μm. Figure 8 In the description, the electrode main body 51 and the short side ridgeline 71 around the concave portion 15c are focused, but the distance L2 is preferably set to the above-mentioned distance L2 in the electrode main body 51 and the short side ridgeline 71 around the other concave portions 15a, 15b, and 15d. In this case, the distances L2 corresponding to the concave portions 15a, 15b, 15c, and 15d may be the same or different.

[0080] like Figure 8 As shown, the radius R1 of the concave portion 15c is 62 μm after the fourth metal layer 64 is formed, and the dimensional tolerance is ±15 μm. In addition, the radius R1 of the concave portion 15c is 55 μm after the fifth metal layer 65 is formed, and the dimensional tolerance is ±15 μm. In addition, Figure 8 Although it is schematically shown, the origin position of the radius R1 may be different from the actual position. In addition, the radius R1 is not limited to the radius R1 of the concave portion 15c, and it is preferable to set the radius R1 to the other concave portions 15a, 15b, and 15d as well.

[0081] The operation of the coil component 10 configured as above will be described below. The external electrodes 14a and 14c are used as input terminals. The external electrodes 14b and 14d are used as output terminals.

[0082] A differential transmission signal consisting of a first signal and a second signal with a phase difference of 180 degrees is input to the external electrodes 14a and 14c, respectively. The first signal and the second signal are differential mode signals, so when passing through the coils 22a and 22b, mutually opposite magnetic fluxes are generated in the coils 22a and 22b. Moreover, the magnetic flux generated in the coil 22a and the magnetic flux generated in the coil 22b cancel each other out. Therefore, in the coils 22a and 22b, there is almost no increase or decrease in the magnetic flux caused by the flow of the first signal and the second signal. That is, the coils 22a and 22b do not generate a back electromotive force that hinders the flow of the first signal and the second signal. Therefore, the coil component 10 has only a very small impedance relative to the first signal and the second signal.

[0083] On the other hand, when the first signal and the second signal contain common mode noise, the common mode noise generates a magnetic flux in the same direction as the coils 22a and 22b when passing through the coils 22a and 22b. Therefore, the common mode noise flows in the coils 22a and 22b, thereby increasing the magnetic flux. As a result, the coils 22a and 22b generate a back electromotive force that hinders the flow of the common mode noise. Therefore, the coil component 10 has a large impedance relative to the first signal and the second signal.

[0084] Next, use Figures 9 to 18 A method for manufacturing the coil component 10 will be described.

[0085] like Fig. 9 As shown, the coil conductors 31 and 41 in the mother laminate M13 are aligned, and the positions corresponding to the recesses 15a, 15b, 15c, and 15d of the photoresist PR1 are exposed on the bottom surface M11a of the mother substrate M11. At this time, a mask Mk is arranged at the position other than the recesses 15a to 15d, so that the positions corresponding to the recesses 15a, 15b, 15c, and 15d of the photoresist PR1 can be exposed as described above. The mother laminate M13 is a laminate 13, and is arranged between the mother substrate M11 that becomes the first substrate 11 and the mother substrate M12 that becomes the second substrate 12. In the following, the component composed of the mother substrate M11, the mother substrate M12, and the mother laminate M13 is described as the mother body M. The mother laminate M13 includes, in addition to the coil conductors 31 and 41 , conductor portions M13 a serving as lead portions 32 to 37 and 42 to 46 .

[0086] Next, if Fig.10 As shown in FIG. 1 , the photoresist PR1 is developed. As a result, the photoresist PR1 has openings PR1x at locations where the positions corresponding to the recessed portions 15a, 15b, 15c, and 15d are exposed.

[0087] Next, if Fig.11 As shown, through the opening PR1x of the photoresist PR1, for example, by sandblasting, a through hole H15 is formed at a position where the recessed portions 15a, 15b, 15c, and 15d are to be formed relative to the mother substrate M11. At this time, a notch N may be formed in the conductor portion M13a at a position corresponding to the through hole H15 in the mother laminate M13. In addition, the through hole H15 may be formed by laser processing in addition to sandblasting, or by a combination of sandblasting and laser processing.

[0088] Next, if Fig.12 As shown, the photoresist PR1 is removed, for example, by an organic solvent.

[0089] Next, if Fig.13 As shown, the first metal layer 61 and the second metal layer 62 are formed by sputtering on the entire bottom surface M11 a of the mother body M (mother substrate M11 ).

[0090] Next, if Fig.14 As shown in FIG. 1 , the photoresist PR2 is formed on the planar portion around the through hole H15 of the bottom surface M11a. That is, the photoresist PR2 has an opening PR2x at a position corresponding to the through hole H15.

[0091] Next, if Fig.15As shown, the first metal layer 61 and the second metal layer 62 are used as power supply films, and the third metal layer 63 is formed by electroplating.

[0092] Next, if Fig.16 As shown, the photoresist PR2 is removed by an organic solvent in the same manner as the photoresist PR1. Then, the first metal layer 61 and the second metal layer 62 exposed from the third metal layer 63 are removed by, for example, wet etching.

[0093] Next, if Fig.17 As shown, the mother substrate M12 is formed into a thin plate shape by grinding or polishing.

[0094] Next, if Fig.18 As shown, the mother body M is cut on the cutting line CL into the size of each coil component 10. Thus, the conductor portion M13a of the mother laminate M13 becomes each lead portion 32 to 37, 42 to 46. After cutting, chamfering is performed by rolling or the like. At this time, the third metal layer 63 of this example is formed at a position separated from the short side edge line portion 71, so that the third metal layer 63 can be suppressed from extending along the short side edge line portion 71.

[0095] Next, the fourth metal layer 64 and the fifth metal layer 65 are formed by electroplating in this order to form the external electrodes 14a, 14b, 14c, and 14d, thereby completing the coil component 10. When the fourth metal layer 64 and the fifth metal layer 65 are formed, as described above, the third metal layer 63 is suppressed from extending along the short side edge line portion 71, so the fourth metal layer 64 and the fifth metal layer 65 are also suppressed from extending along the short side edge line portion 71.

[0096] According to the present embodiment described above, the following effects are achieved.

[0097] (1) The first metal layer 61 as the base layer is formed on the bottom surface 11a at a position separated from the short side ridge line portion 71 between the bottom surface 11a and the side surfaces 11c and 11d, thereby suppressing the first metal layer 61 from extending along the short side ridge line portion 71 due to rolling or the like. By suppressing the first metal layer 61 from extending along the short side ridge line portion 71, stress concentration at this portion can be suppressed. Therefore, the first substrate 11 around this portion can be prevented from being broken and the external electrodes 14a, 14b, 14c, and 14d from being cracked.

[0098] (2) On the bottom surface 11a, the second metal layer 62 and the third metal layer 63 are formed at a position separated from the short side edge line portion 71, so that the second metal layer 62 and the third metal layer 63 are prevented from extending along the short side edge line portion 71 due to rolling or the like. By preventing the second metal layer 62 and the third metal layer 63 from extending along the short side edge line portion 71, stress concentration at this portion can be suppressed. Therefore, the first substrate 11 around this portion can be prevented from being broken and the external electrodes 14a, 14b, 14c, and 14d from being cracked.

[0099] (3) In the structure where the external electrodes 14a, 14b, 14c, 14d further include the connection portion 52 provided in the recessed portion 15a, 15b, 15c, 15d and electrically connecting the coils 22a, 22b and the electrode body portion 51, the stress concentration at this portion can be suppressed by suppressing the extension of the third metal layer 63 along the short side ridge portion 71. Therefore, the rupture of the first substrate 11 around this portion and the generation of cracks in the external electrodes 14a, 14b, 14c, 14d can be suppressed.

[0100] (4) The third metal layer 63 of the connection portion 52 is formed at least to a position overlapping with the concave portion ridgeline portion 74 of the concave portions 15a to 15d that are continuous in the direction from the short side ridgeline portion 71 toward the upper surface 11b. That is, in the concave portions 15a to 15d, the third metal layer 63 and the connection portion 52 including the third metal layer 63 can be formed in a wider range. Therefore, when the coil component 10 is connected to the mounting substrate by solder, the connection reliability between the solder and the connection portion 52 of the concave portions 15a to 15d can be improved.

[0101] (5) The connection portion 52 has the same laminated structure as the electrode main body portion 51 , and can therefore be formed in the same manufacturing process as the electrode main body portion 51 .

[0102] (6) The plurality of metal layers 61 to 65 include a fourth metal layer 64 as a coating layer on the third metal layer 63 constituting the low resistance layer. By suppressing the extension of the third metal layer 63 along the short side ridgeline 71, the extension of the fourth metal layer 64 along the short side ridgeline 71 is also suppressed.

[0103] (7) The third metal layer 63 constituting the low resistance layer is a metal layer containing copper, and the fourth metal layer 64 as the coating layer has a metal layer containing nickel. The extension along the short side edge line portion 71 in the fourth metal layer 64 containing nickel is suppressed, so that the corrosion of the first substrate 11 based on the fourth metal layer 64 can be suppressed, thereby contributing to improving the adhesion between the external electrodes 14a, 14b, 14c, 14d and the first substrate 11.

[0104] (8) When the first substrate 11, the laminated body 13, and the second substrate 12 are stacked to form a laminate, the length of the laminate in the stacking direction D is 0.23 mm or less, the length of the laminate along the short side in the direction perpendicular to the stacking direction D is 0.3 mm or less, and the length of the laminate along the long side in the direction perpendicular to the stacking direction D is 0.45 mm or less. In this way, in a small coil component, the protrusion of the side edge line portion 71 along the short side can be suppressed as described above.

[0105] (9) The distance L1 from the recesses 15a to 15d to the distal end 51a of the electrode body 51 adjacent to the recesses 15a to 15d in the direction along the short side is 25 μm or less, so that the electrode bodies 51 can be prevented from approaching each other, thereby preventing leakage. As a result, the L value is improved, thereby improving the noise elimination performance.

[0106] (10) The distance L2 from the short-side ridgeline 71 to the electrode body 51 is 3.3 μm or more and 16.7 μm or less, so that the electrode body 51 can be appropriately suppressed from protruding along the short-side ridgeline 71 .

[0107] (Other Embodiments)

[0108] In addition, the above-mentioned embodiment can be implemented by modification as follows. The above-mentioned embodiment and the following modification examples can be implemented by combining with each other within the range that there is no technical contradiction.

[0109] In the above embodiment, the external electrodes 14 a , 14 b , 14 c , and 14 d are formed of five metal layers 61 , 62 , 63 , 64 , and 65 , but the present invention is not limited thereto and the number of layers may be four or less or six or more.

[0110] In the above embodiment, the recesses 15a, 15b, 15c, and 15d are provided at the four corners, but the present invention is not limited thereto. For example, a recess may be added at the center of the bottom surface 11a of the first substrate 11. In addition, another recess may be added between the recess 15a and the recess 15c, and between the recess 15b and the recess 15d.

[0111] In the above embodiment, the third metal layer 63 is formed at a position away from the short-side ridgeline portion 71 , but the third metal layer 63 may be formed at a position away from the long-side ridgeline portion 72 .

[0112] In the above embodiment, the coil component 10 is configured to have four external electrodes 14a, 14b, 14c, and 14d, but the present invention is not limited thereto. A structure having six external electrodes may also be adopted. In this case, one external electrode is provided between the external electrode 14a and the external electrode 14c arranged along the long side direction (X-axis direction) of the coil component 10, and one external electrode is provided between the external electrode 14b and the external electrode 14d arranged along the long side direction (X-axis direction) of the coil component 10.

[0113] In the above embodiment, the coil component 10 including a planar spiral coil conductor is used, but the present invention is not limited thereto. For example, a coil component including a three-dimensional spiral coil conductor spiraling in the stacking direction D may be used.

[0114] In the above embodiment, the first metal layer 61 as the base layer and the second and third metal layers 62 and 63 as the low resistance layers are arranged at positions separated from the short side edge line portion 71, but the present invention is not limited to this. For example, a structure in which only the base layer is arranged at a position separated from the short side edge line portion 71 may be adopted.

[0115] In the above embodiment, the low resistance layer is composed of two layers, namely, the second metal layer 62 and the third metal layer 63 , but the present invention is not limited thereto. The low resistance layer may be composed of one layer or three or more layers.

[0116] In the above embodiment, the connection part 52 is made into the same laminated structure as the electrode body part 51, but the present invention is not limited thereto, and the connection part and the electrode body part may be made into different laminated structures. For example, the number of laminated layers in the connection part and the electrode body part may be different.

Claims

1. A coil component, characterized in that: The coil component comprises: A magnetic substrate having a bottom surface having a rectangular shape including long sides and short sides, an upper surface located on the opposite side of the bottom surface, and side surfaces on the long sides and short sides connecting the bottom surface and the upper surface; a laminate having an insulating layer formed on the upper surface and a coil formed in the insulating layer; as well as An external electrode, disposed on the bottom surface, The magnetic substrate has a recessed portion provided at a corner of the bottom surface. The external electrode has an electrode main body, and the electrode main body is provided around the recessed portion on the bottom surface. The electrode body is formed by stacking a plurality of metal layers, and the electrode body has a base layer, which is a metal layer located innermost in the stacking direction of the stack among the plurality of metal layers. The base layer is formed on the bottom surface at a position separated from the short side edge line between the bottom surface and the side surface of the short side. In the case where an end of the electrode main body portion adjacent to the recessed portion in the direction along the short side is defined as a distal end, A distance between the recess and the distal end in a direction along the short side is 25 μm or less.

2. The coil component according to claim 1, characterized in that The plurality of metal layers include a low resistance layer having a lower resistance than the base layer on the base layer, The low-resistance layer is formed on the bottom surface at a position separated from the short-side ridgeline.

3. The coil component according to claim 1 or 2, characterized in that: The external electrode further includes a connection portion, which is provided in the recessed portion and electrically connects the coil and the electrode main body.

4. The coil component according to claim 3, characterized in that The connecting portion is integrally formed with the electrode main body, and is formed from the electrode main body to a ridgeline portion of the recessed portion between the recessed portion and the side surface on the short side.

5. The coil component according to claim 3, characterized in that: The connecting portion has the same laminated structure as the electrode main body portion.

6. The coil component according to claim 2, characterized in that The plurality of metal layers include a coating layer on the low resistance layer.

7. The coil component according to claim 6, characterized in that The low resistance layer is a metal layer containing copper, The coating layer includes a metal layer containing nickel.

8. The coil component according to claim 1 or 2, characterized in that: The coil component further includes a magnetic layer formed on the laminated body. When the magnetic substrate, the laminate, and the magnetic layer are stacked to form a laminate, the length of the laminate in the stacking direction is less than 0.23 mm, the length of the laminate along the short side in the direction perpendicular to the stacking direction is less than 0.3 mm, and the length of the laminate along the long side in the direction perpendicular to the stacking direction is less than 0.45 mm.

Images