Coil member and method of manufacturing coil member

Abstract

Provided are a coil component in which deposition of a plating material is suppressed and which is advantageous for miniaturization, and a method for manufacturing the coil component. The coil component has a body containing a magnetic material; a coil embedded in the body; an external electrode electrically connected to the coil and provided on a bottom surface of the body; and an insulating layer provided on the bottom surface of the body, wherein the insulating layer has an opening portion, and the external electrode is provided in the opening portion.

Description

Technical Field

[0001] This disclosure relates to coil components and methods for manufacturing coil components. Background Technology

[0002] It is known to have laminated coil components having a magnetic body portion containing metallic magnetic powder. In such laminated coil components, the metallic magnetic powder contained in the magnetic body portion is mixed with conductive particles such as iron, which may lead to the formation of an overlay of the plating. Here, it is known to apply an insulating coating with high insulation resistance to the upper and lower surfaces to ensure surface insulation (Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-254917

[0004] The laminated coil component described in Patent Document 1 has an insulating coating applied to its upper and lower surfaces, making miniaturization and reduction difficult. Summary of the Invention

[0005] The purpose of this disclosure is to provide a coil component and a method for manufacturing the coil component that suppresses the epitaxy of the plating and facilitates miniaturization and low profile.

[0006] This disclosure includes the following methods.

[0007] [1] A coil component, which is a stacked coil component, has: a body containing magnetic material; a coil embedded in the body; an external electrode electrically connected to the coil and disposed on the bottom surface of the body; and an insulating layer disposed on the bottom surface of the body. In the stacked coil component, the insulating layer has an opening and the external electrode is disposed in the opening.

[0008] [2] In the coil component described in [1] above, the external electrode includes a bottom electrode and a plating layer disposed on the bottom electrode.

[0009] [3] In the coil component described in [2] above, the bottom electrode is disposed in the body and the plating layer is disposed in the opening.

[0010] [4] In any of the above [1] to [3] coil components, in a plan view seen from the bottom side of the body, the area of ​​the opening is less than or equal to the area of ​​the bottom electrode.

[0011] [5] In any one of the coil components described in [1] to [4] above, the plating layer is configured to be flush with the surface of the insulating layer.

[0012] [6] In any one of the coil components described in [1] to [4] above, the plating layer is recessed from the bottom surface of the insulating layer.

[0013] [7] In any one of the coil components described in [1] to [4] above, the plating layer is configured to protrude from the insulating layer.

[0014] [8] In any one of the coil components described in [1] to [7] above, the plating layer is a Cu layer, a Ni-Sn layer, a Ni-Au layer, a Ni-Cu layer or a Cu-Ni-Au layer.

[0015] [9] In any one of the coil components described in [1] to [8] above, the insulating layer is a resin material with a higher insulation resistance than the main body.

[0016]

[10] In any one of the coil components described in [1] to [9] above, the magnetic material comprises metallic magnetic particles.

[0017]

[11] A method for manufacturing a coil component is a method for manufacturing a laminated coil component, the coil component comprising: a body containing a magnetic material; a coil embedded in the body; an external electrode electrically connected to the coil and disposed on the bottom surface of the body; and an insulating layer disposed on the bottom surface of the body. The method for manufacturing the coil component includes the following steps: laminating a conductive paste layer as a bottom electrode on the bottom surface of a laminate comprising a magnetic paste layer and a conductive paste layer, and firing it to form a laminated block; forming an insulating layer having an opening that exposes at least a partial area of ​​the bottom electrode on the surface of the fired laminated block; forming a plating layer on the bottom electrode at the opening; and cutting the laminated block.

[0018] According to this disclosure, it is possible to provide a coil component that suppresses plating epitaxy by forming an external electrode within an opening in the insulating layer, and which is conducive to miniaturization and low profile. Attached Figure Description

[0019] Figure 1 This is a perspective view schematically showing the stacked coil component 1 of Embodiment 1 of the present disclosure.

[0020] Figure 2 It is a schematic representation Figure 1 A cross-sectional view of the stacked coil component 1 along the II-II section shown.

[0021] Figure 3 It is a schematic representation Figure 1 A cross-sectional view of the stacked coil component 1 along section III-III.

[0022] Figure 4 It is a schematic representation Figure 1The cross-sectional view of the stacked coil component 1 along the IV-IV section shown.

[0023] Figure 5 It is a schematic representation Figure 1 The cross-sectional view of the stacked coil component 1 along the cut surface VV is shown.

[0024] Figure 6 yes Figure 1 A schematic bottom view of the stacked coil component 1 shown.

[0025] Figure 7 Yes Figure 1 The figure illustrates the manufacturing method of the stacked coil component 1 shown.

[0026] Figure 8 Yes Figure 1 The figure illustrates the manufacturing method of the stacked coil component 1 shown.

[0027] Explanation of reference numerals in the attached figures

[0028] 1...Laminated coil component; 2...Body; 3...Coil; 3a, b, c, d, e...Internal electrode layers; 3p, q, r, s...Conductors with through holes; 4a, b...Lead-out portions; 5a, b...Bottom electrodes; 6a, b...Plating layers; 7...Insulating layers; 8a, b...External electrodes; 9a, b...Openings; 21...Magnetic paste layer; 22...Magnetic paste layer; 23...Magnetic paste layer; 24...Magnetic paste layer; 25...Magnetic paste layer; 26...Magnetic paste layer; 27...Magnetic paste layer; 2 8...Magnetic paste layer; 29...Magnetic paste layer; 31...Conductor paste layer; 32...Conductor paste layer; 33...Conductor paste layer; 34...Conductor paste layer; 35...Conductor paste layer; 41...Conductor paste layer; 42...Conductor paste layer; 43...Conductor paste layer; 44...Conductor paste layer; 45...Conductor paste layer; 46...Conductor paste layer; 47...Conductor paste layer; 48...Conductor paste layer; 51...Conductor paste layer; 52...Conductor paste layer; 81...Non-magnetic ferrite paste layer; 82...Non-magnetic ferrite paste layer. Detailed Implementation

[0029] The coil component of this disclosure will now be described in detail with reference to the accompanying drawings. The shape and arrangement of the coil component and structural elements are not limited to the examples shown. Sometimes, components with the same function are labeled with the same reference numerals in different drawings. For ease of explanation and understanding, the description is divided into embodiments, but parts of the structure shown in different embodiments can be substituted or combined. In the embodiments described below, descriptions of technical content common to the foregoing are sometimes omitted, and only the differences are described. In particular, sometimes the same effects based on the same structure are not mentioned sequentially in each embodiment. The size and positional relationships of the components shown in the drawings are sometimes exaggerated for clarity.

[0030] (Implementation Method 1)

[0031] The perspective view of the stacked coil component 1 in this embodiment is provided by Figure 1 As shown, the bottom view is composed of Figure 6 It is shown. Furthermore, the II-II sectional view of the laminated coil component 1 is shown by... Figure 2 To illustrate schematically, the III-III sectional view is composed of Figure 3 Schematic illustration shows that the IV-IV section is composed of Figure 4 To illustrate schematically, the VV sectional view is composed of Figure 5 It is shown schematically.

[0032] like Figures 1-6 As shown, the stacked coil component 1 of this embodiment has a generally rectangular parallelepiped shape. Additionally, the attached... Figure 1 In this design, the lower surface is called the bottom surface, the upper surface is called the top surface, and the other surfaces are called the side surfaces. Generally, the stacked coil component 1 has a body 2, a coil 3 embedded in the body 2, external electrodes 8a and 8b, and an insulating layer 7 covering the bottom surface of the body 2. The insulating layer 7 has openings 9a and 9b. External electrodes 8a and 8b are respectively located within the openings 9a and 9b. Multiple internal electrode layers 3a to 3e are connected through conductive holes 3p to 3s to form the coil 3. The external electrodes 8a and 8b have bottom surface electrodes 5a and 5b located inside the body 2 and plating layers 6a and 6b disposed above the bottom surface electrodes 5a and 5b and located within the openings 9a and 9b. The external electrodes 8a and 8b are electrically connected to both ends of the coil 3 via leads 4a and 4b, respectively.

[0033] The coil component disclosed herein preferably has a length (L) of 1.0 mm or more and 6.0 mm or less, a width (W) of 0.2 mm or more and 2.0 mm or less, and a height (T) of 0.2 mm or more and 2.0 mm or less. More preferably, it has a length of 1.0 mm or more and 2.0 mm or less, a width of 0.5 mm or more and 1.2 mm or less, and a height of 0.5 mm or more and 1.2 mm or less.

[0034] In this embodiment, the body 2 includes a magnetic body layer containing magnetic material.

[0035] Typically, the aforementioned magnetic materials are metallic magnetic particles.

[0036] The metallic magnetic material constituting the aforementioned metallic magnetic particles is not particularly limited as long as it possesses magnetic properties. Examples include iron, cobalt, nickel, or gadolinium, or alloys containing one or more of these. Iron or iron alloys are preferred. Iron can be iron itself or an iron derivative, such as a complex. There are no particular limitations on such iron derivatives, but examples include iron carbonyl, a complex of iron and CO, preferably iron pentacarbonyl. Hard iron carbonyl with an onion-skin structure (a structure in which concentric spherical layers form from the center of the particle) is particularly preferred (e.g., hard (H) carbonyl iron manufactured by BASF). There are no particular limitations on the iron alloy, but examples include Fe-Si alloys, Fe-Si-Cr alloys, and Fe-Si-Al alloys. The aforementioned alloys may also contain B, C, etc., as other secondary components. The content of these secondary components is not particularly limited, but for example, it can be 0.1% by mass or more and 5.0% by mass or less, preferably 0.5% by mass or more and 3.0% by mass or less. The aforementioned metallic magnetic materials may be of only one type or of two or more types.

[0037] In a preferred embodiment, the metallic magnetic material is an Fe-Si alloy or an Fe-Si-Cr alloy. When using an Fe-Si alloy as the metallic magnetic powder, the Si content is preferably 2.0 at% or more and 8.0 at% or less. When using an Fe-Si-Cr alloy, the Si content is preferably 2.0 at% or more and 8.0 at% or less, and the Cr content is preferably 0.2 at% or more and 6.0 at% or less.

[0038] The aforementioned metallic magnetic particles may also contain impurities such as Cr, Mn, Cu, Ni, P, and S. These impurities are not intentionally added, and their content can be, for example, less than 1% by mass, preferably less than 0.1% by mass.

[0039] The aforementioned magnetic metal particles preferably have an average particle size of 0.5 μm or more and 50 μm or less, more preferably an average particle size of 1 μm or more and 30 μm or less, and even more preferably an average particle size of 2 μm or more and 20 μm or less. By making the average particle size of the aforementioned magnetic metal particles 0.5 μm or more, the handling of the magnetic metal particles becomes easier. Furthermore, by making the average particle size of the aforementioned magnetic metal particles 50 μm or less, a higher filling rate of the magnetic metal particles can be achieved, thereby improving the magnetic properties of the magnetic layer.

[0040] Here, the aforementioned average particle size refers to the average value of the equivalent circular diameter of the metallic magnetic particles in a SEM (scanning electron microscope) image of the cross-section of the magnetic layer. For example, the aforementioned average particle size can be obtained as follows: for the cross-section obtained by cutting the stacked coil component 1, multiple regions (e.g., 5 regions) are photographed using SEM (e.g., 130 μm × 100 μm), and the SEM image is analyzed using image analysis software (e.g., Asahi Kasei Engineering Co., Ltd., A-Image (registered trademark)). The equivalent circular diameter of more than 500 metallic particles is determined, and its average value is calculated.

[0041] The aforementioned metallic magnetic particles preferably have an oxide coating.

[0042] The aforementioned oxide film can be an oxide film of the metal that constitutes the metallic magnetic particles.

[0043] The thickness of the oxide film is not particularly limited, but it is preferably 1 nm or more and 100 nm or less, more preferably 3 nm or more and 50 nm or less, and even more preferably 5 nm or more and 30 nm or less. For example, it can be 10 nm or more and 30 nm or 5 nm or more and 20 nm or less. By increasing the thickness of the oxide film, the resistivity of the magnetic layer is improved. In addition, by reducing the thickness of the oxide film, the amount of metallic magnetic particles in the magnetic layer can be increased, the magnetic properties of the magnetic layer can be improved, and the miniaturization of the magnetic layer can be easily achieved.

[0044] The aforementioned metallic magnetic particles are bonded together through the aforementioned oxide film.

[0045] The aforementioned metallic magnetic particles can also be coated with an insulating film. The aforementioned insulating film can also be a film other than the aforementioned oxide film.

[0046] The insulating film described above is preferably a film containing a metal oxide, and more preferably a film containing an oxide of Si.

[0047] Examples of methods for forming the aforementioned insulating film include mechanochemical methods and sol-gel methods. The sol-gel method is particularly preferred when forming a film of Si oxide. In forming a film containing Si oxide by the sol-gel method, the film can be formed as follows: a sol-gel coating agent containing Si alkoxide is mixed with a silane coupling agent containing organic chains, and the mixture is applied to the surface of metallic magnetic particles. After dehydration and bonding by heat treatment, the particles are dried at a predetermined temperature.

[0048] The insulating film described above may cover only a portion of the surface of the metallic magnetic particles, or it may cover the entire surface of the metallic magnetic particles. Furthermore, the shape of the insulating film is not particularly limited; it may be mesh-like or layered. In a preferred embodiment, at least 50%, preferably 70%, more preferably 80%, further preferably 90%, and particularly preferably 100% of the surface area of ​​the metallic magnetic particles is covered by the insulating film. By covering the surface of the metallic particles with the insulating film, the resistivity within the magnetic layer can be increased.

[0049] The thickness of the insulating film is not particularly limited, but is preferably 1 nm or more and 100 nm or less, more preferably 3 nm or more and 50 nm or less, and even more preferably 5 nm or more and 30 nm or less. For example, it can be 10 nm or more and 30 nm or 5 nm or more and 20 nm or less. By increasing the thickness of the insulating film, the resistivity inside the magnetic layer can be improved. In addition, by decreasing the thickness of the insulating film, the amount of metallic magnetic particles in the magnetic layer can be increased, the magnetic properties of the magnetic layer can be improved, and the miniaturization of the magnetic layer can be easily achieved.

[0050] In addition to the magnetic layer mentioned above, the main body 2 may also have a non-magnetic layer.

[0051] The non-magnetic layer is preferably disposed between the internal electrode layers.

[0052] By incorporating a non-magnetic layer, the DC overlap characteristics of the stacked coil components are improved. Furthermore, the insulation between the internal electrodes is enhanced.

[0053] The aforementioned non-magnetic layer is preferably composed of a sintered non-magnetic material containing at least Fe, Cu and Zn as main components.

[0054] In the above-mentioned sintered nonmagnetic materials, the Fe content, converted to Fe2O3, is preferably 40.0 mol% or more and 49.5 mol% or less (based on the total of the main components, the same applies below), and more preferably 45.0 mol% or more and 49.5 mol% or less.

[0055] In the above-mentioned sintered non-magnetic materials, the Cu content, converted to CuO, is preferably 4.0 mol% or more and 12.0 mol% or less (based on the total of main components, the same applies below), and more preferably 6.0 mol% or more and 10.0 mol% or less.

[0056] In the above-mentioned sintered non-magnetic materials, the Zn content is not particularly limited and can be the remainder other than Fe and Cu, which are the other main components mentioned above. When converted to ZnO, it is preferably 39.5 mol% or more and 56.0 mol% or less (based on the total of main components, the same applies below), and more preferably 40.5 mol% or more and 49.0 mol% or less.

[0057] Excellent electrical properties can be obtained by adjusting the contents of Fe, Cu, and Zn to the ranges described above.

[0058] In this disclosure, the sintered nonmagnetic material may also contain additives. Examples of additives in the sintered nonmagnetic material include Mn, Co, Sn, Bi, and Si, but it is not limited to these. The content (addition amount) of Mn, Co, Sn, Bi, and Si is converted to Mn3O4, Co3O4, SnO2, Bi2O3, and SiO2, respectively, and preferably is 0.1 mass fraction or more and 1 mass fraction or less relative to the total mass fraction of the main components (Fe (converted to Fe2O3), Zn (converted to ZnO), Cu (converted to CuO), and Ni (converted to NiO)). Furthermore, the sintered nonmagnetic material may also contain impurities that are unavoidable in manufacturing.

[0059] The thickness of the non-magnetic layer is preferably 5 μm or more and 180 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 30 μm or more and 100 μm or less.

[0060] Multiple internal electrode layers 3a to 3e are connected through through-hole conductors 3p to 3s to form coil 3.

[0061] The aforementioned internal electrode layer comprises a conductive material. This conductive material includes silver, copper, gold, or alloys thereof. Preferably, the internal electrode layer comprises silver as a conductive material, and more preferably, it comprises only silver.

[0062] The thickness of the aforementioned internal electrode layer is not particularly limited, but it is preferably 15 μm or more and 150 μm or less, and more preferably 20 μm or more and 40 μm or less.

[0063] Lead-out portions 4a and 4b electrically connect the ends of coil 3 to bottom electrodes 5a and 5b. In this embodiment, lead-out portion 4a connects the inner electrode layer 3a at the lower end of the coil to the bottom electrode 5a, and lead-out portion 4b connects the inner electrode layer 3e at the upper end of the coil to the bottom electrode 5b. Lead-out portion 4b is longer than lead-out portion 4a.

[0064] Leads 4a and 4b preferably contain the same conductive material as the internal electrode layer. This conductive material may include silver, copper, gold, or alloys thereof. Leads 4a and 4b preferably contain silver, and more preferably only silver, as the conductive material.

[0065] The insulating layer 7 is disposed on the bottom surface of the body 2.

[0066] In the laminated coil component 1, the insulating layer 7 is only provided on the bottom surface. In other words, the insulating layer 7 is not present on the upper surface and side surfaces of the body 2. Furthermore, the coil component of this disclosure is preferably provided in this manner, but is not limited thereto. For example, the insulating layer may be provided on the side surfaces in addition to the bottom surface, or it may be provided on both the side surfaces and the top surface.

[0067] The insulating layer 7 has openings 9a and 9b.

[0068] The openings 9a and 9b are configured to expose the bottom electrodes 5a and 5b. Preferably, only the bottom electrodes are exposed at the openings, while the body 2 remains unexposed. In other words, in a plan view from the bottom side of the body 2, the area of ​​the openings 9a and 9b is less than or equal to the area of ​​the bottom electrodes 5a and 5b, and the openings 9a and 9b are located inside the bottom electrodes 5a and 5b. By configuring the openings to prevent the body 2 from being exposed, it is possible to suppress the contact between the plating solution and the body 2 during the plating process to prevent the formation of an epitaxial plating layer.

[0069] The insulating layer 7 is made of a resin material with a higher insulation resistance than the material of the body 2.

[0070] Examples of resin materials with high electrical insulation properties include acrylic resins, epoxy resins, and polyamides. Furthermore, the resin material may contain fillers composed of insulating materials.

[0071] External electrodes 8a and 8b are disposed on the bottom surface of the stacked coil component 1. The external electrodes 8a and 8b include bottom surface electrodes 5a and 5b and plating layers 6a and 6b disposed on the bottom surface electrodes 5a and 5b. The bottom surface electrodes 5a and 5b are disposed within the body 2, and the plating layers 6a and 6b are disposed within the openings 9a and 9b.

[0072] In the stacked coil component 1, the bottom electrodes 5a and 5b are embedded in the body 2 with one main surface exposed. However, the coil component of this disclosure is not limited to this manner. For example, the bottom electrodes may be partially embedded in the bottom surface of the body, or they may be disposed on the bottom surface of the body.

[0073] In the stacked coil component 1, the bottom electrodes 5a and 5b extend from the leads 4a and 4b to approximately the center of the body 2 in the W direction at the bottom surface of the body 2. However, the coil component of this disclosure is not limited to this arrangement; for example, the bottom electrodes may be positioned at the same location as the leads.

[0074] The bottom electrodes 5a and 5b preferably contain the same conductive material as the inner electrode layer. This conductive material may include silver, copper, gold, or alloys thereof. The bottom electrodes 5a and 5b preferably contain silver as the conductive material, and more preferably contain only silver.

[0075] The plating layers 6a and 6b are disposed within the openings 9a and 9b on the bottom electrodes 5a and 5b. Preferably, in a plan view viewed from the bottom side of the body 2, the plating layers are disposed on the entire opening.

[0076] In the laminated coil component 1, the thickness (length in the T direction) of the plating layers 6a and 6b is less than the height (length in the T direction) of the openings 9a and 9b. That is, the plating layers 6a and 6b are recessed from the bottom surface of the insulating layer 7. In other words, the laminated coil component 1 has a recess on the bottom surface defined by the side of the opening and the plating layers. Furthermore, the coil component of this disclosure is not limited to this manner; for example, the plating layers may completely fill the openings. In one embodiment, the plating layers may be configured to be flush with the surface of the insulating layer. In other embodiments, the plating layers may be configured to protrude from the insulating layer.

[0077] The plating layers 6a and 6b can be single layers or multiple layers.

[0078] The plating layers 6a and 6b may preferably include a plating layer containing Cu, a plating layer containing Ni, a plating layer containing Sn, or an Au plating layer.

[0079] In one embodiment, the plating layers 6a and 6b can be Cu plating layers, Ni-Sn plating layers, Ni-Au plating layers, Ni-Cu plating layers, or Cu-Ni-Au plating layers on the bottom electrode.

[0080] The above description illustrates the stacked coil component of this disclosure through examples, but the stacked coil component of this disclosure is not limited to the above-described embodiments and various modifications can be made.

[0081] Next, the manufacturing method of the laminated coil component disclosed herein will be described.

[0082] The multilayer coil component disclosed herein can be obtained by multiplying magnetic paste, non-magnetic paste, and internal conductor paste and then heat-treating them.

[0083] In detail, the stacked coil component 1 can be manufactured as follows.

[0084] As a magnetic paste, a magnetic paste containing metallic magnetic particles is prepared. The magnetic paste is obtained by mixing and kneading a mixture of metallic magnetic particles with cellulose, polyvinyl butyral, etc., as binders, and terpineol, butyl diethylene glycol acetate, etc., as solvents.

[0085] As a nonmagnetic paste, a nonmagnetic paste containing ferrite material is prepared. As the ferrite material, Fe2O3, ZnO, CuO, and other desired additives are weighed to a predetermined composition. The weighed mixture, along with pure water, a dispersant, and PSZ media, is placed in a ball mill and mixed and pulverized. The resulting slurry is dried and temporarily calcined at 700–800°C for 2–3 hours. A predetermined amount of solvent (ketone-based solvent, etc.), resin (polyvinyl acetal, etc.), and plasticizer (alkyd plasticizer, etc.) are added to the obtained nonmagnetic ferrite material (temporarily calcined powder). After mixing using a planetary mixer, the mixture is further dispersed using a three-roll mill to produce a nonmagnetic ferrite paste.

[0086] As a conductor paste, a conductor paste, such as silver paste, is prepared. The conductor paste is obtained by mixing conductor powder with a predetermined amount of solvent, resin, dispersant, etc.

[0087] Next, create a layered structure of the above-mentioned paste.

[0088] A substrate (not shown) is prepared by laminating a heat-release sheet and a polyethylene terephthalate (PET) film onto a metal plate. Magnetic paste is then screen-printed onto this substrate a predetermined number of times to form a magnetic paste layer 21. The resulting magnetic paste layer 21 becomes the outer layer of the coil component. Figure 7 (a)

[0089] Next, a conductor paste layer 31, which serves as a coil conductor, is formed on top of the aforementioned magnetic paste layer 21. Furthermore, a magnetic paste layer 22 is formed in the areas where the conductor paste layer 31 is not formed. Figure 7 (b)

[0090] Next, a non-magnetic ferrite paste layer 81 is formed on the conductor paste layer 31, excluding the areas connected to the coil conductors to be printed subsequently and the areas connected to the lead-out conductors. Next, a magnetic paste layer 23 is formed in the areas outside the non-magnetic ferrite paste layer 81. Figure 7 (c)

[0091] Next, conductor paste layer 32, which becomes the through-hole conductor (the conductor connected to the coil conductor printed later), and conductor paste layer 41, which becomes the lead-out conductor, are formed. Figure 7 (d)

[0092] Next, a conductor paste layer 33, which becomes the coil conductor, and a conductor paste layer 42, which becomes the lead conductor, are formed. Furthermore, a magnetic paste layer 24 is formed in the areas where conductor paste layers 33 and 42 are not formed. Figure 7 (e)

[0093] Next, a non-magnetic ferrite paste layer 82 is formed on the conductor paste layer 33, except for the area connected to the coil conductor to be printed next. Furthermore, a conductor paste layer 34, which serves as a via conductor, is formed in the area connected to the coil conductor to be printed next, and a conductor paste layer 43, which serves as a lead-out conductor, is also formed. And, a magnetic paste layer 25 is formed in the areas excluding these regions. Figure 7 (f)

[0094] Repeat the above a predetermined number of times. Figure 7 The processes (e) and (f) yield a laminate containing a magnetic paste layer 26, a conductive paste layer 35, and a conductive paste layer 44. Figure 7 (g)

[0095] Next, conductor paste layers 45 and 46 are printed at the locations where the conductors will be led out, and magnetic paste layer 27 is printed in the remaining areas. Figure 7 (h)). The above operation is repeated a predetermined number of times to obtain a laminate containing magnetic paste layer 28 and conductive paste layers 47 and 48. Figure 7 (i)

[0096] Next, conductive paste layers 51 and 52 are formed in the area of ​​the bottom electrode that becomes the external electrode, and magnetic paste layer 29 is formed in the area where conductive paste layers 51 and 52 are not formed. Figure 7 (j)

[0097] Finally, the PET film is peeled off from the metal plate to create the laminated block.

[0098] The resulting laminated blocks are subjected to pressure treatment, such as hot isostatic pressing (WIP).

[0099] The pressurized laminated blocks are degreased and placed in a firing furnace for firing.

[0100] The firing temperature is preferably 600°C or higher and 800°C or lower, more preferably 650°C or higher and 750°C or lower.

[0101] The firing time is preferably 30 minutes or more and 90 minutes or less, more preferably 40 minutes or more and 80 minutes or less.

[0102] The firing process described above is preferably carried out in the atmosphere.

[0103] The fired laminated blocks are immersed in resin and then thermo-cured. Epoxy resin is preferably used as the resin.

[0104] For a resin-impregnated laminated block, a photosensitive resist resin is coated onto the entire surface (lower surface) of the bottom electrode by screen printing, followed by drying, to obtain an insulating layer 7. Figure 8 (a)

[0105] After patterning exposure along the shape of the bottom electrode, the electrode is immersed in developing solution to remove the insulating layer on the bottom electrode. Figure 8 (b)

[0106] Next, chemical plating is performed to form a coating layer on the bottom electrode. Figure 8 (c)

[0107] Next, the stacked blocks are cut using a cutting machine or similar equipment to achieve single-piece or array-like processing.

[0108] As described above, the stacked coil component 1 can be obtained.

[0109] Industrial availability

[0110] The stacked coil component of the present invention can be widely used as an inductor and other devices for various applications.

Claims

1. A coil component, which is a stacked coil component, comprising: The body is a body in which a magnetic body layer containing metallic magnetic particles and an internal electrode layer are stacked together to form a coil inside. An external electrode, electrically connected to the coil, is disposed on the bottom surface of the body; and An insulating layer is provided only on the bottom surface of the body. The coil component is characterized in that... The external electrode includes a bottom electrode having a main surface that is embedded in the body such that the main surface is exposed from the bottom surface of the body. The insulating layer has an opening that exposes at least partially a portion of the main surface that is exposed from the bottom surface of the body. The external electrode includes a plating layer disposed at the opening above the bottom electrode. In a plan view taken from the bottom side of the body, the area of ​​the opening is less than or equal to the area of ​​the bottom electrode.

2. The coil component according to claim 1, characterized in that, The plating layer is configured to be flush with the surface of the insulating layer.

3. The coil component according to claim 1, characterized in that, The coating layer is recessed from the bottom surface of the insulating layer.

4. The coil component according to claim 1, characterized in that, The plating layer is configured to protrude from the insulating layer.

5. The coil component according to claim 1, characterized in that, The coating layer is a Cu layer, a Ni-Sn layer, a Ni-Au layer, a Ni-Cu layer, or a Cu-Ni-Au layer.

6. The coil component according to any one of claims 1 to 5, characterized in that, The insulating layer is a resin material with a higher insulation resistance than the body.

7. A method for manufacturing a coil component, which is a method for manufacturing a stacked coil component, the coil component comprising: a body, which is formed by stacking a magnetic body layer containing metallic magnetic particles and an internal electrode layer to form a coil inside; an external electrode electrically connected to the coil and disposed on the bottom surface of the body; and an insulating layer disposed only on the bottom surface of the body. The method for manufacturing the coil component is characterized by comprising the following steps: A laminated block is formed by laminating the conductive paste layer and the magnetic paste layer, which are both bottom electrodes, on the bottom surface of the laminate, and then firing them. An insulating layer is formed on the surface of the bottom electrode of the fired laminated block, with an opening that exposes at least a partial area of ​​the bottom electrode. In a plan view from the bottom side of the body, the area of ​​the opening is less than or equal to the area of ​​the bottom electrode. A plating layer is formed on the bottom electrode at the opening; as well as Cut the stacked block.

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