Coil component and method for manufacturing same

Abstract

[Problem] To improve reliability of a product, regarding a coil component having a structure in which a coil layer formed by alternately layering a plurality of conductor layers and a plurality of interlayer insulating layers is embedded in a magnetic element body. [Solution] A coil component 1 comprises: a magnetic element body 10; a coil part 20 that is embedded in the magnetic element body 10; a protective insulating layer 70 that covers a surface of the magnetic element body 10 and has openings 71, 72 for exposing electrode patterns 51-54, 61-64; and external terminals E1, E2 that are in contact with the electrode patterns 51-54, 61-64 via the openings 71, 72. The protective insulating layer 70 is colored such that the transmittance of light having a first wavelength included in a first wavelength region is 50% or more, and the transmittance of light having a second wavelength included in a second wavelength region not overlapping with the first wavelength region is less than 50%.

Description

Coil component and manufacturing method thereof

[0001] The present disclosure relates to a coil component and a method for manufacturing the same.

[0002] Patent Document 1 discloses a coil component having a structure in which a coil layer, which is made up of a plurality of conductor layers and a plurality of interlayer insulating layers alternately stacked, is embedded in a magnetic base body.

[0003] Japanese Patent Application Laid-Open No. 2022-055132

[0004] In the coil component disclosed in Patent Document 1, the magnetic body is entirely covered with a protective insulating layer, which prevents plating from adhering to unwanted locations even when electrolytic plating is applied to the surfaces of the external terminals.

[0005] This disclosure describes a technology for further improving product reliability in a coil component having a structure in which a coil layer formed by alternately stacking multiple conductor layers and multiple interlayer insulating layers is embedded in a magnetic base body.

[0006] A coil component according to one aspect of the present disclosure comprises a magnetic base body made of resin containing conductive magnetic powder, a coil section in which a plurality of conductor layers and a plurality of interlayer insulating layers are alternately stacked, the plurality of conductor layers including a coil conductor pattern embedded in the magnetic base body and an electrode pattern exposed from the magnetic base body, a protective insulating layer covering the surface of the magnetic base body and having an opening through which at least a portion of the electrode pattern is exposed, and an external terminal that contacts at least a portion of the electrode pattern through the opening, wherein the protective insulating layer is colored so that the transmittance of light of a first wavelength included in a first wavelength range is 50% or more and the transmittance of light of a second wavelength included in a second wavelength range that does not overlap with the first wavelength range is less than 50%.

[0007] A method for manufacturing a coil component according to one aspect of the present disclosure includes: a first step of forming a coil layer by alternately laminating a plurality of conductor layers, each including a coil conductor pattern and an electrode pattern, and a plurality of interlayer insulating layers; a second step of embedding the coil layer in a magnetic body made of a resin containing conductive magnetic powder; a third step of exposing the electrode patterns by singulating or grinding the magnetic body; a fourth step of covering surfaces of the magnetic body and the electrode patterns with a protective insulating layer; a fifth step of performing a visual inspection of the protective insulating layer; a sixth step of exposing at least a portion of the electrode patterns by providing openings in the protective insulating layer; and a seventh step of forming external terminals that contact at least a portion of the electrode patterns through the openings. The protective insulating layer has a transmittance of 50% or more for light of a first wavelength included in a first wavelength range, a transmittance of less than 50% for light of a second wavelength included in a second wavelength range not overlapping the first wavelength range, and is colored so that the transmittance for light of the first wavelength is at least twice the transmittance for light of the second wavelength; in a sixth step, first light having a first spectrum in which wavelength components including the first wavelength are more abundant than wavelength components including the second wavelength is irradiated, thereby forming openings while performing image recognition of the electrode pattern through the protective insulating layer; and in a fifth step, appearance inspection is performed by irradiating second light having a second spectrum in which wavelength components including the second wavelength are more abundant than wavelength components including the first wavelength.

[0008] According to the present disclosure, a technology is provided for further improving product reliability in a coil component having a structure in which a coil layer formed by alternately stacking multiple conductor layers and multiple interlayer insulating layers is embedded in a magnetic base body.

[0009] FIG. 1 is a schematic perspective view showing the appearance of a coil component 1 according to an embodiment of the present disclosure. FIG. 2 is an xy cross-sectional view of the coil component 1. FIG. 3 is a cross-sectional view of the coil component 1 taken along line A-A shown in FIG. 2. FIG. 4 is a graph showing an example of the light transmittance of a protective insulating layer 70, showing the light transmittance in the wavelength range of 400 to 800 nm. FIGS. 5(a) to 5(d) are process diagrams for explaining the manufacturing process of the coil component 1. FIG. 6 is a schematic perspective view showing a state in which the magnetic base body 10 has been singulated. FIG. 7(a) is a schematic perspective view showing a state in which the protective insulating layer 70 has been formed on the surface of the magnetic base body 10, and FIG. 7(b) is a cross-sectional view thereof. FIG. 8(a) is a schematic perspective view showing a state in which openings 71 and 72 have been formed in the protective insulating layer 70, and FIG. 8(b) is a cross-sectional view thereof.

[0010] Hereinafter, embodiments of the technology according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0011] Fig. 1 is a schematic perspective view showing the appearance of a coil component 1 according to an embodiment of the present disclosure, Fig. 2 is an xy cross-sectional view of the coil component 1, and Fig. 3 is a cross-sectional view of the coil component 1 taken along line AA shown in Fig. 2.

[0012] 1 to 3, the coil component 1 according to this embodiment is a surface-mount chip component that can be used as an inductor for a power supply circuit, and includes a magnetic base body 10 made up of magnetic layers 11 to 14, a coil section 20 embedded in the magnetic base body 10, a protective insulating layer 70 covering the surface of the magnetic base body 10, and external terminals E1 and E2 exposed from the protective insulating layer 70. The configuration of the coil section 20 will be described later, but in this embodiment, one coil is formed by stacking four conductor layers having coil conductor patterns. One end of the coil is connected to external terminal E1, and the other end of the coil is connected to external terminal E2.

[0013] The magnetic element 10 is a composite member made of resin containing conductive magnetic powder such as ferrite powder or metal magnetic powder, and forms a magnetic path for magnetic flux generated by passing a current through the coil. When metal magnetic powder is used as the magnetic powder, a permalloy-based material can be used. Furthermore, liquid or powdered epoxy resin can be used as the resin.

[0014] Unlike typical laminated coil components, the coil component 1 according to this embodiment is mounted upright so that the z-direction, which is the lamination direction, is parallel to the circuit board. Specifically, the surface S1 constituting the xz plane is used as the mounting surface. The external terminals E1 and E2 are exposed from the surface S1. The other surfaces may be entirely covered with a protective insulating layer 70. The external terminals E1 and E2 may be made of a conductive paste such as nano-silver paste or nano-copper paste. The surfaces of the external terminals E1 and E2 exposed from the protective insulating layer 70 may be covered with a Ni / Sn laminate film, a Ni / Pt / Au laminate film, a Ni / Au laminate film, or the like to ensure solder wettability. The external terminals E1 and E2 are not embedded in the magnetic base body 10.

[0015] The protective insulating layer 70 protects the magnetic element 10 and also serves to prevent the conductive magnetic powder contained in the magnetic element 10 from falling off. The surface of the magnetic element 10 has irregularities caused by protruding or fallen conductive magnetic powder, and the protective insulating layer 70 covers the surface of the magnetic element 10 to fill in these irregularities. This improves adhesion between the magnetic element 10 and the protective insulating layer 70. The protective insulating layer 70 may cover the entire surface of the magnetic element 10, or the magnetic element 10 may be partially exposed.

[0016] As shown in Fig. 3, the coil portion 20 has a configuration in which interlayer insulating layers 40 to 44 and conductor layers 31 to 34 are alternately stacked. The conductor layers 31 to 34 are connected to each other via through holes formed in the interlayer insulating layers 41 to 43 to form a coil. One axial side of the coil portion 20 is covered with a magnetic layer 11, the other axial side of the coil portion 20 is covered with a magnetic layer 12, and the inner diameter region of the coil portion 20 is embedded with a magnetic layer 13. As shown in Fig. 2, the outer region of the coil portion 20 is covered with a magnetic layer 14. These magnetic layers 11 to 14 may be made of the same composite material, or may be made of partially different composite materials.

[0017] The interlayer insulating layers 40 to 44 are made of, for example, resin, and a non-magnetic material is used for at least the interlayer insulating layers 41 to 43. The lowermost interlayer insulating layer 40 and the uppermost interlayer insulating layer 44 may be made of a magnetic material.

[0018] The conductor layer 31 is a first conductor layer formed on the upper surface of the magnetic body layer 11 with the interlayer insulating layer 40 interposed therebetween. The conductor layer 31 is provided with a coil conductor pattern C1 wound spirally for two turns, and two electrode patterns 51 and 61. The coil conductor pattern C1 is entirely embedded in the magnetic body 10, and portions of the surfaces of the electrode patterns 51 and 61 are exposed from the magnetic body 10. The electrode pattern 51 is connected to the outer peripheral end of the coil conductor pattern C1, while the electrode pattern 61 is provided independently of the coil conductor pattern C1.

[0019] The conductor layer 32 is a second conductor layer formed on the upper surface of the conductor layer 31 with the interlayer insulating layer 41 interposed therebetween. The conductor layer 32 is provided with a coil conductor pattern C2 wound spirally with two turns, and two electrode patterns 52 and 62. The coil conductor pattern C2 is entirely embedded in the magnetic body 10, and portions of the surfaces of the electrode patterns 52 and 62 are exposed from the magnetic body 10. The inner peripheral end of the coil conductor pattern C2 is connected to the inner peripheral end of the coil conductor pattern C1 through a via provided in the interlayer insulating layer 41. Both the electrode patterns 52 and 62 are provided independently of the coil conductor pattern C2.

[0020] The conductor layer 33 is a third conductor layer formed on the upper surface of the conductor layer 32 with the interlayer insulating layer 42 interposed therebetween. The conductor layer 33 is provided with a coil conductor pattern C3 wound spirally for two turns, and two electrode patterns 53 and 63. The coil conductor pattern C3 is entirely embedded in the magnetic body 10, and portions of the surfaces of the electrode patterns 53 and 63 are exposed from the magnetic body 10. The outer peripheral end of the coil conductor pattern C3 is connected to the outer peripheral end of the coil conductor pattern C2 through a via provided in the interlayer insulating layer 42. Both the electrode patterns 53 and 63 are provided independently of the coil conductor pattern C3.

[0021] The conductor layer 34 is a fourth conductor layer formed on the upper surface of the conductor layer 33 with the interlayer insulating layer 43 interposed therebetween. The conductor layer 34 is provided with a coil conductor pattern C4 wound in a spiral shape with two turns, and two electrode patterns 54 and 64. The coil conductor pattern C4 is entirely embedded in the magnetic body 10, and portions of the surfaces of the electrode patterns 54 and 64 are exposed from the magnetic body 10. The electrode pattern 64 is connected to the outer peripheral end of the coil conductor pattern C4, while the electrode pattern 54 is provided independently of the coil conductor pattern C4. The inner peripheral end of the coil conductor pattern C4 is connected to the inner peripheral end of the coil conductor pattern C3 through a via provided in the interlayer insulating layer 43.

[0022] As a result, an eight-turn coil is formed by the coil conductor patterns C1 to C4.

[0023] Furthermore, the electrode patterns 51 to 54 are connected to one another via via conductors V1 to V3 that penetrate the interlayer insulating layers 41 to 43. Similarly, the electrode patterns 61 to 64 are connected to one another via via conductors V4 to V6 that penetrate the interlayer insulating layers 41 to 43. Here, the via conductors V1 to V3 are formed at different positions when viewed from the stacking direction, and the via conductors V4 to V6 are also formed at different positions when viewed from the stacking direction. In the cross section shown in FIG. 3, the electrode patterns 51 to 54 and 61 to 64 are covered with a protective insulating layer 70. The electrode patterns 51 to 54 and 61 to 64 are embedded in the magnetic base body 10 except for their exposed surfaces.

[0024] The electrode patterns 51 to 54 constituting one end of the coil are connected to the external terminal E1 via an opening 71 provided in the protective insulating layer 70. The electrode patterns 61 to 64 constituting the other end of the coil are connected to the external terminal E2 via an opening 72 provided in the protective insulating layer 70. The openings 71 and 72 may have a tapered shape in which the opening area decreases in the depth direction. This makes it possible to ensure a sufficient opening area for the openings 71 and 72 while suppressing contact between the external terminals E1 and E2 and the magnetic base body 10. Furthermore, the external terminals E1 and E2 may have portions that overlap with the magnetic base body 10 via the protective insulating layer 70. This makes it possible to ensure a sufficient surface area for the external terminals E1 and E2.

[0025] The protective insulating layer 70 is not colorless and transparent but is colored. FIG. 4 is a graph showing an example of the light transmittance of the protective insulating layer 70, showing the light transmittance in the wavelength range of 400 to 800 nm. In the example shown in FIG. 4, the protective insulating layer 70 is colored so that the light transmittance in the blue range (wavelength = 430 to 490 nm) is higher than the light transmittance in the red range (wavelength = 640 to 770 nm). More specifically, the blue range (wavelength = 430 to 490 nm) includes wavelengths with a light transmittance of 50% or more, while the red range (wavelength = 640 to 770 nm) includes wavelengths with a light transmittance of less than 50%. For example, the light transmittance in the wavelength range around 470 nm in the blue range is 80% or more, with a peak of approximately 90%. Furthermore, the light transmittance in the wavelength range around 700 nm in the red range is 30% or less, with a bottom of approximately 20%. In the above example, the transmittance of light in the vicinity of 470 nm wavelength, which is included in the blue region, is more than twice the transmittance of light in the vicinity of 700 nm wavelength, which is included in the red region.

[0026] In the example shown in FIG. 4 , the light transmittance in the blue region (wavelength = 430 to 490 nm) is generally 80% or more, whereas the light transmittance in the red region (wavelength = 640 to 770 nm) is 30% or less in the wavelength region of 640 to 720 nm, but 50% or more in the wavelength region of 750 to 770 nm. Thus, the light transmittance may be 50% or more in some wavelength regions of the red region. Also, in the example shown in FIG. 4 , the light transmittance in the orange region (wavelength = 590 to 640 nm) is also generally 30% or less. Therefore, the light transmittance in the blue region is more than twice that of the orange region. Furthermore, the light transmittance in the yellow region (wavelength = 550 to 590 nm) is generally 50% or less, and particularly 30% or less in the wavelength region of 580 to 590 nm. Therefore, the light transmittance in the blue region is more than twice that of the light transmittance in the wavelength region of 580 to 590 nm, which is included in the yellow region.

[0027] Furthermore, the infrared region (wavelength = 770 to 1200 nm) may also include wavelengths with a light transmittance of 80% or more. For example, the transmittance of light with a wavelength of 800 nm, which is included in the infrared region, is approximately 85%. In this case, the transmittance of light with a wavelength of 800 nm, which is included in the infrared region, is more than twice the transmittance of light with a wavelength of around 700 nm, which is included in the red region, the transmittance of light in the orange region, and the transmittance of light with a wavelength of 580 to 590 nm, which is included in the yellow region. Note that, since wavelength regions less than 400 nm and wavelength regions greater than 1200 nm are difficult to recognize even using a CCD camera, there are no particular restrictions on the transmittance in these wavelength regions.

[0028] The protective insulating layer 70 may be made of a material in which a resin and a coloring agent are added to an inorganic coating agent. The inorganic coating agent may be made of, for example, silica. The resin may be made of, for example, acrylic resin. The inorganic coating agent and resin may themselves be colorless and transparent, but the protective insulating layer 70 is colored by the coloring agent. The coloring agent is, for example, cyanine blue. However, the protective insulating layer 70 does not need to contain an inorganic coating agent, and may instead be made of a resin and a coloring agent.

[0029] Next, a method for manufacturing the coil component 1 according to this embodiment will be described.

[0030] 5A to 5D are process diagrams illustrating the manufacturing process of the coil component 1 according to this embodiment.

[0031] 5(a), a support substrate S having a predetermined strength is first prepared, and interlayer insulating layers 40-44 and conductor layers 31-34 are alternately formed on its surface. The interlayer insulating layers 40-44 can be formed by applying a resin material using a spin coating method. The conductor layers 31-34 can be formed by forming a base metal film using a thin-film process such as sputtering, and then plating the film to the desired thickness using an electroplating method.

[0032] Next, as shown in FIG. 5( b), a space is formed by removing the interlayer insulating layers 40-44 and the conductor layers 31-34 located in the inner diameter region surrounded by the coil conductor patterns C1-C4 and in the outer region outside the coil conductor patterns C1-C4. Then, as shown in FIG. 5( c), a composite material made of a resin containing conductive magnetic powder is embedded in this space to form the magnetic base body 10. Next, as shown in FIG. 5( d), the magnetic base body 10 is singulated by dicing. As a result, portions of the electrode patterns 51-54 and 61-64 are exposed from the cut surfaces, as shown in FIG. 6. The step of exposing the electrode patterns 51-54 and 61-64 may be performed by grinding the surface of the magnetic base body 10 after singulation.

[0033] Next, the surface of the magnetic base body 10 is covered with a protective insulating layer 70. As a result, as shown in the schematic perspective view of Fig. 7(a) and the xy sectional view of Fig. 7(b), not only the surface of the magnetic base body 10 but also the exposed surfaces of the electrode patterns 51-54 and 61-64 are covered with the protective insulating layer 70. Methods that can be used to form the protective insulating layer 70 include the sol-gel method, dip coating, spray coating, and electrostatic spraying. In any of these methods, the irregularities on the surface of the magnetic base body 10 are filled in with the protective insulating layer 70, and the two are firmly adhered to each other.

[0034] After the protective insulating layer 70 is formed, an appearance inspection of the protective insulating layer 70 is performed. The appearance inspection of the protective insulating layer 70 is mainly performed by irradiating the protective insulating layer 70 with light in a wavelength region in which the protective insulating layer 70 has a low light transmittance. For example, if the protective insulating layer 70 has the light transmittance characteristics shown in FIG. 4 , the appearance inspection of the protective insulating layer 70 is performed by irradiating the protective insulating layer 70 with light having a spectrum in which wavelength components in the red region are more abundant than wavelength components in the blue region or infrared region. When light having such a spectrum is irradiated, most of the irradiated light is reflected without passing through the protective insulating layer 70, so that the appearance inspection is less affected by the magnetic base body 10 that is the base, and the protective insulating layer 70 can be more clearly recognized as an image.

[0035] Next, as shown in FIG. 8( a) which is a schematic perspective view and FIG. 8( b) which is an xy cross-sectional view, openings 71 and 72 are formed in the protective insulating layer 70. The openings 71 and 72 can be formed, for example, by irradiating a laser beam. Here, the opening 71 needs to be formed in a position where the electrode patterns 51 to 54 are exposed, and the opening 72 needs to be formed in a position where the electrode patterns 61 to 64 are exposed. Therefore, image recognition of the electrode patterns 51 to 54 and the electrode patterns 61 to 64 is performed through the protective insulating layer 70. The size of the opening 71 may be smaller than the size of the exposed surfaces of the electrode patterns 51 to 54. The size of the opening 72 may be smaller than the size of the exposed surfaces of the electrode patterns 61 to 64.

[0036] When image recognition of the electrode patterns 51-54 and the electrode patterns 61-64 is performed, light in a wavelength range in which the light transmittance of the protective insulating layer 70 is high is irradiated. For example, if the light transmittance of the protective insulating layer 70 has the characteristics shown in FIG. 4, image recognition of the electrode patterns 51-54 and the electrode patterns 61-64 is performed by irradiating the electrode patterns with light having a spectrum in which wavelength components in the blue range or the infrared range are more abundant than wavelength components in the red range. When light having such a spectrum is irradiated, most of the irradiated light passes through the protective insulating layer 70, allowing for clearer image recognition of the electrode patterns 51-54 and the electrode patterns 61-64.

[0037] The order of visual inspection of the protective insulating layer 70 and the formation of the openings 71 and 72 may be reversed. The thickness of the protective insulating layer 70 may be 5 μm or more and 30 μm or less. By making the thickness of the protective insulating layer 70 5 μm or more, sufficient insulation properties can be ensured. By making the thickness of the protective insulating layer 70 30 μm or less, it becomes possible to clearly recognize the image of the electrode patterns 51 to 54 and the electrode patterns 61 to 64.

[0038] Thereafter, the external terminals E1 and E2 are formed by applying a conductive paste through the openings 71 and 72. Then, a laminated film made of Ni / Sn or the like is formed on the surfaces of the external terminals E1 and E2 by electrolytic plating, thereby completing the coil component 1 according to this embodiment.

[0039] As described above, in this embodiment, the use of a colored protective insulating layer 70 makes it possible to improve the accuracy of the image recognition required for visual inspection of the protective insulating layer 70 and for forming the openings 71, 72 compared to when a colorless and transparent protective insulating layer is used. This makes it possible to further improve the reliability of the manufactured coil component 1. Furthermore, because the surface of the magnetic base body 10 is covered with the protective insulating layer 70, no plating film is formed on the surface of the magnetic base body 10 when electrolytic plating is performed on the surfaces of the external terminals E1, E2.

[0040] The above describes embodiments of the technology according to the present disclosure, but the technology according to the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the technology, and it goes without saying that these modifications are also included within the scope of the technology according to the present disclosure.

[0041] For example, the coil axis of the coil component 1 exemplified above is parallel to the substrate on which the coil component is mounted (z direction), but the technology disclosed herein is not limited to this, and the direction of the coil axis may be parallel to the substrate (for example, the x and z directions described above), perpendicular to the substrate (for example, the y direction described above), or in some other direction.

[0042] Furthermore, the technology according to the present disclosure is not limited, for example, by the number of coils built into the coil component. In the above-described exemplary embodiment, the coil component 1 includes one coil portion 20. Without being limited to this, the technology according to the present disclosure may be applied to a coil component having two or more coils. For example, the coils may be arranged in the z direction described above, or in another direction. Furthermore, two or more coil components may form a common mode filter or an array inductor. When a coil component includes multiple coils, the coil component may be provided with multiple terminal electrodes. In this case, openings may be provided in the protective insulating layer so that a portion of the electrode pattern of each coil is exposed from the magnetic base body, and each terminal electrode may be connected to the electrode pattern of each coil through the opening.

[0043] The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

[0044] A coil component according to one aspect of the present disclosure includes a magnetic element made of a resin containing conductive magnetic powder, a coil section formed by alternately stacking multiple conductor layers and multiple interlayer insulating layers, each including a coil conductor pattern embedded in the magnetic element and an electrode pattern exposed from the magnetic element, a protective insulating layer covering the surface of the magnetic element and having an opening through which at least a portion of the electrode pattern is exposed, and an external terminal contacting at least a portion of the electrode pattern through the opening, wherein the protective insulating layer is colored so that the transmittance of light of a first wavelength included in a first wavelength range is 50% or more and the transmittance of light of a second wavelength included in a second wavelength range not overlapping the first wavelength range is less than 50%, thereby enabling improved accuracy in visual inspection of the protective insulating layer and image recognition required for forming the opening.

[0045] In the coil component, the protective insulating layer may be colored so that the transmittance of the first wavelength light is at least twice as high as the transmittance of the second wavelength light, thereby enabling further improvement in the accuracy of the image recognition required for visual inspection of the protective insulating layer and for forming openings.

[0046] In the coil component, the protective insulating layer may have a transmittance of 80% or more for light of the first wavelength and a transmittance of 30% or less for light of the second wavelength, which makes it possible to further improve the accuracy of the image recognition required for visual inspection of the protective insulating layer and for forming openings.

[0047] In the coil component described above, the first wavelength region may be a blue region or an infrared region, which allows image recognition required for forming the opening to be performed using light with a spectrum containing a strong blue or infrared component.

[0048] In the coil component described above, the second wavelength region may be a red region, which makes it possible to perform visual inspection of the protective insulating layer using light with a spectrum containing a strong red region component.

[0049] In the coil component, the protective insulating layer may be made of a material in which a resin and a coloring agent are added to an inorganic coating agent, thereby making it possible to obtain high insulation properties.

[0050] In the coil component described above, the surface of the magnetic body may have irregularities caused by protruding or fallen conductive magnetic powder, and the protective insulating layer may be provided so as to fill in the irregularities, thereby improving adhesion between the magnetic body and the protective insulating layer.

[0051] In the coil component, the external terminals may have portions that overlap with the magnetic body via a protective insulating layer, thereby ensuring a sufficient area for the external terminals.

[0052] In the coil component, the opening may have a tapered shape, which makes it possible to prevent contact between the external terminal and the magnetic body while ensuring a sufficient opening area of ​​the opening.

[0053] A method for manufacturing a coil component according to one aspect of the present disclosure includes: a first step of forming a coil layer by alternately laminating a plurality of conductor layers, each including a coil conductor pattern and an electrode pattern, and a plurality of interlayer insulating layers; a second step of embedding the coil layer in a magnetic body made of a resin containing conductive magnetic powder; a third step of exposing the electrode patterns by singulating or grinding the magnetic body; a fourth step of covering surfaces of the magnetic body and the electrode patterns with a protective insulating layer; a fifth step of performing a visual inspection of the protective insulating layer; a sixth step of exposing at least a portion of the electrode patterns by providing openings in the protective insulating layer; and a seventh step of forming external terminals that contact at least a portion of the electrode patterns through the openings. The protective insulating layer has a transmittance of 50% or more for light of a first wavelength included in a first wavelength range, a transmittance of less than 50% for light of a second wavelength included in a second wavelength range not overlapping the first wavelength range, and is colored so that the transmittance for light of the first wavelength is at least twice the transmittance for light of the second wavelength, and in a sixth step, an opening is formed while image-recognizing the electrode pattern through the protective insulating layer by irradiating the protective insulating layer with first light having a first spectrum in which wavelength components including the first wavelength are more abundant than wavelength components including the second wavelength, and in a fifth step, an appearance inspection is performed by irradiating the protective insulating layer with second light having a second spectrum in which wavelength components including the second wavelength are more abundant than wavelength components including the first wavelength. This improves the accuracy of the image recognition required for the appearance inspection of the protective insulating layer and the formation of the opening, making it possible to manufacture a highly reliable coil component.

[0054] This application claims the benefit of Japanese Patent Application No. 2024-009841, filed on January 26, 2024, the entire disclosure of which is incorporated herein by reference.

[0055] REFERENCE SIGNS LIST 1 coil component 10 magnetic base body 11 to 14 magnetic layer 20 coil portion 31 to 34 conductor layer 40 to 44 interlayer insulating layer 51 to 54, 61 to 64 electrode pattern 70 protective insulating layer 71, 72 opening C1 to C4 coil conductor pattern E1, E2 external terminal S support substrate S1 surface V1 to V6 via conductor

Claims

1. A coil component comprising: a magnetic element made of resin containing conductive magnetic powder; a coil section in which multiple conductor layers including a coil conductor pattern embedded in the magnetic element and an electrode pattern exposed from the magnetic element and multiple interlayer insulating layers are alternately stacked; a protective insulating layer covering the surface of the magnetic element and having an opening through which at least a portion of the electrode pattern is exposed; and an external terminal contacting at least a portion of the electrode pattern through the opening, wherein the protective insulating layer has a transmittance of 50% or more for light of a first wavelength included in a first wavelength range, and a transmittance of less than 50% for light of a second wavelength included in a second wavelength range not overlapping the first wavelength range.

2. The coil component according to claim 1, wherein the protective insulating layer is colored so that the transmittance of the light of the first wavelength is at least twice the transmittance of the light of the second wavelength.

3. The coil component according to claim 2, wherein the protective insulating layer has a transmittance of 80% or more for light of the first wavelength and a transmittance of 30% or less for light of the second wavelength.

4. The coil component according to claim 2, wherein the first wavelength region is a blue region.

5. The coil component according to claim 2, wherein the first wavelength range is an infrared range.

6. The coil component according to claim 2, wherein the second wavelength region is a red region.

7. The coil component according to claim 2, wherein the protective insulating layer is made of a material in which a resin and a coloring agent are added to an inorganic coating agent.

8. A coil component according to any one of claims 1 to 7, wherein the surface of the magnetic base body has irregularities caused by the protruding or fallen conductive magnetic powder, and the protective insulating layer is provided so as to fill in the irregularities.

9. A coil component according to any one of claims 1 to 7, wherein the external terminals have portions that overlap the magnetic body with the protective insulating layer interposed therebetween.

10. A coil component according to any one of claims 1 to 7, wherein the opening has a tapered shape.

11. A manufacturing method comprising: a first step of forming a coil layer by alternately laminating a plurality of conductor layers, each including a coil conductor pattern and an electrode pattern, and a plurality of interlayer insulating layers; a second step of embedding the coil layer in a magnetic body made of a resin containing conductive magnetic powder; a third step of exposing the electrode patterns by dividing or grinding the magnetic body; a fourth step of covering the surfaces of the magnetic body and the electrode patterns with a protective insulating layer; a fifth step of performing an appearance inspection of the protective insulating layer; a sixth step of exposing at least a portion of the electrode patterns by forming an opening in the protective insulating layer; and a seventh step of forming external terminals that contact the at least a portion of the electrode patterns through the opening. the protective insulating layer is colored so that the transmittance of light of a first wavelength included in a first wavelength range is 50% or more, the transmittance of light of a second wavelength included in a second wavelength range not overlapping the first wavelength range is less than 50%, and the transmittance of light of the first wavelength is at least twice the transmittance of light of the second wavelength; in the sixth step, the openings are formed while image-recognizing the electrode pattern through the protective insulating layer by irradiating first light having a first spectrum in which wavelength components including the first wavelength are more abundant than wavelength components including the second wavelength; and in the fifth step, the appearance inspection is performed by irradiating second light having a second spectrum in which wavelength components including the second wavelength are more abundant than wavelength components including the first wavelength.

Images