Coil component and method of manufacturing the same

Abstract

The invention provides a coil component and a manufacturing method thereof. The coil component may include: a body having a first surface and a second surface opposite to each other in a first direction; the supporting component is arranged in the main body; a coil disposed on the support member; an external electrode disposed on the first surface of the body; and a connection portion disposed within the body to connect the coil and the external electrode, the connection portion having one surface in contact with the coil and the other surface in contact with the external electrode, in which the connection portion may include a welded portion formed at an end portion in contact with the coil.

Description

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0108765 filed on August 21, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] The present disclosure relates to a coil assembly and a method for manufacturing the same. Background Art

[0003] An inductor (a type of coil component) is a typical passive electronic component used in electronic devices along with resistors and capacitors.

[0004] As electronic devices increasingly achieve high performance and miniaturization, electronic components used in the electronic devices are increasing in number and becoming smaller and smaller.

[0005] In addition, setting the external electrode on the lower surface of the main body (the surface on which the coil component is mounted on the printed circuit board (PCB)) can be beneficial to the miniaturization and integration of the coil component, but in the case of a bottom electrode structure (in which the external electrode is set on the lower surface of the main body and the volume of the magnetic material in the coil component can be maximized), if there are manufacturing process advantages, there are requirements for the electrode structure. Summary of the Invention

[0006] One aspect of the present disclosure is to maximize the effective volume within a coil assembly of limited size by connecting the coil and the external electrode within the body to improve the inductance characteristics and saturation current (I sat )characteristic.

[0007] Another aspect of the present disclosure is to obtain process advantages (such as preventing poor connection between the coil and the external electrode, preventing diffusion defects in the external electrode plating, etc.) through the process of forming a connecting portion, wherein the connecting portion (for connecting the coil to the external electrode) is pre-formed and then bonded to the coil.

[0008] According to one aspect of the present disclosure, a coil component may be provided, comprising: a main body having a first surface and a second surface opposite to each other in a first direction; a coil arranged in the main body; an external electrode arranged on the first surface of the main body; and a connecting portion arranged in the main body to connect the coil and the external electrode, the connecting portion having one surface in contact with the coil and another surface in contact with the external electrode, wherein the connecting portion may include a welding portion formed at an end in contact with the coil.

[0009] According to another aspect of the present disclosure, a method for manufacturing a coil component may be provided, the method comprising: forming a coil; forming a connecting portion; and welding the connecting portion to both ends of the coil to form a welding portion at the end of the connecting portion in contact with the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other aspects, features and advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which: Figure 1 is a perspective view schematically showing a coil assembly according to a first embodiment of the present disclosure; Figure 2 yes Figure 1 Exploded perspective diagram; Figure 3 It is shown along Figure 1 A diagram of a cross section taken along line II'; Figure 4 yes Figure 3 A magnified view of area A; Figure 5 It is shown along Figure 1 1-1 '; Figure 6 、 Figure 7 and Figure 8 is a diagram schematically illustrating a manufacturing process of a coil component according to a first embodiment of the present disclosure; Figure 9 Schematically shows the coil component according to the second embodiment of the present disclosure corresponding to Figure 3 ; and Figure 10 、 Figure 11 and Figure 12 is a diagram schematically illustrating a manufacturing process of a coil component according to a second embodiment of the present disclosure. DETAILED DESCRIPTION

[0011] The terms used in this application are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless otherwise clearly stated in the context, singular expressions include plural expressions. In this application, terms such as "including" or "having" are intended to indicate that there are features, quantities, steps, operations, components, parts and / or combinations thereof described in the specification, and it should be understood that this does not exclude the possibility of existing or adding one or more other features, quantities, steps, operations, components, parts and / or combinations thereof. Throughout the specification, the term "on ... " indicates being located above or below the target portion and does not necessarily mean being located on the upper side relative to the direction of gravity.

[0012] Furthermore, in the contact relationship between various components, the term “coupled” not only means a case where the various components are in direct physical contact, but also includes a case where other components are interposed between the various components and the various components are in contact with the other components, respectively.

[0013] For convenience of description, the size (eg, thickness) of each component shown in the drawings is arbitrarily represented, and thus the present disclosure is not necessarily limited to the size (eg, thickness) shown in the drawings.

[0014] In the drawings, T (1) may be defined as a first direction or thickness direction, L (2) may be defined as a second direction or length direction, and W (3) may be defined as a third direction or width direction.

[0015] Hereinafter, a coil component according to an embodiment will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and repeated descriptions thereof will be omitted.

[0016] Various types of electronic components are used in electronic devices, and among these electronic components, various types of coil components may be appropriately used to remove noise and the like.

[0017] For example, in electronic devices, coil components can be used as power inductors, high-frequency inductors, ordinary magnetic beads, high-frequency magnetic beads (for example, magnetic beads for GHz bands), common mode filters, etc.

[0018] First embodiment.

[0019] Figure 1 is a perspective view schematically showing a coil component 1000 according to a first embodiment of the present disclosure. Figure 2 yes Figure 1 Exploded three-dimensional diagram. Figure 3 It is shown along Figure 1 Schematic diagram of a cross section taken along line II'. Figure 4 yes Figure 3 Magnified view of area A. Figure 5 It is shown along Figure 1 Schematic diagram of a cross section taken along line II-II'.

[0020] In addition, Figure 1 In order to more clearly illustrate the coupling relationship between components, the first insulating layer 610 and the second insulating layer 620 on the body 100 that can be applied to this embodiment are not shown.

[0021] The coil component 1000 according to the present embodiment may include connecting portions 410 and 420 , which respectively connect the coil 300 and the external electrodes 510 and 520 within the main body 100 , and the connecting portions 410 and 420 may be pre-formed on the separate core DC and then welded to the coil 300 , and magnetic sheets may be stacked to form the main body 100 .

[0022] The coil component 1000 according to the present embodiment may have a bottom electrode structure in which the external electrodes 510 and 520 are provided on the lower surface of the body 100 (i.e., the first surface 101 of the body 100), thereby improving the inductance characteristics due to the increase in the effective volume of the coil component 1000 and also improving the saturation current (I sat )characteristic.

[0023] In addition, the process of implementing the bottom electrode can be simpler than the existing process, and the process of forming the connecting portions 410 and 420 according to this embodiment can make it easier to highly control the connecting portions 410 and 420 compared to the case where the connecting portions 410 and 420 are formed by plating from the coil 300 toward the outer electrodes 510 and 520.

[0024] In addition, compared with the case where a via hole is machined in the main body 100 (and connected to the coil 300) after the main body 100 is formed and the connecting portions 410 and 420 are formed by plating, the process of machining the via hole can be omitted, and since the connecting portions 410 and 420 are formed by plating, defects such as clogging inside the via hole can be prevented.

[0025] Furthermore, since the welded portions 411 and 421 are formed by welding between the coil 300 and the connection portions 410 and 420 , physical coupling force and / or connection reliability between the coil 300 and the connection portions 410 and 420 may be improved.

[0026] Hereinafter, main components constituting the coil component 1000 according to the present embodiment will be described in detail.

[0027] Reference Figures 1 to 5 The coil component 1000 according to the first embodiment of the present disclosure may include a body 100, a support member 200, a coil 300, external electrodes 510 and 520, and connection parts 410 and 420 connecting the coil 300 and the external electrodes 510 and 520, respectively.

[0028] The body 100 forms the exterior of the coil component 1000 according to the present embodiment, and the coil 300 may be disposed in the body 100. The coil 300 may be supported by the support member 200, but the present disclosure is not limited thereto, and according to the present embodiment, the coil component 1000 may also have a coreless structure in which the support member 200 is omitted.

[0029] The body 100 may be formed to have a generally hexahedral shape.

[0030] based on Figure 1 In the direction of the body 100, the body 100 includes a first surface 101 and a second surface 102 opposing each other in the thickness direction (T), a third surface 103 and a fourth surface 104 opposing each other in the length direction (L), and a fifth surface 105 and a sixth surface 106 opposing each other in the width direction (W). Each of the third surface 103, the fourth surface 104, the fifth surface 105, and the sixth surface 106 of the body 100 corresponds to a wall surface of the body 100 connecting the first surface 101 and the second surface 102 of the body 100.

[0031] As an example, the body 100 may be formed so that the coil component 1000 formed with the external electrodes 510 and 520 according to the present embodiment has a length of 2.5 mm, a width of 2.0 mm, and a thickness of 0.8 mm, a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.6 mm, a length of 1.6 mm, a width of 0.8 mm, and a thickness of 0.6 mm, a length of 1.6 mm, a width of 0.8 mm, and a thickness of 0.4 mm, a length of 1.4 mm, a width of 1.2 mm, and a thickness of 0.65 mm, a length of 1.0 mm, a width of 0.7 mm, and a thickness of 0.65 mm, a length of 0.8 mm, a width of 0.4 mm, and a thickness of 0.65 mm, or a length of 0.8 mm, a width of 0.4 mm, and a thickness of 0.5 mm, but the present disclosure is not limited thereto. On the other hand, the example values ​​of the length, width, and thickness of the coil component 1000 described above refer to values ​​that do not reflect process errors, and values ​​within the range that can be identified as process errors should be considered to correspond to the above example values.

[0032] Based on an optical microscope image or scanning electron microscope (SEM) image of a lengthwise (L)-thicknesswise (T) cross-section taken from the center of coil component 1000 in the widthwise (W) direction, the length of coil component 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of coil component 1000 and parallel to the lengthwise (L) direction, with the two outermost boundary lines opposing each other in the lengthwise (L) direction of coil component 1000 as shown in the cross-sectional image. Alternatively, the length of coil component 1000 may refer to the minimum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of coil component 1000 and parallel to the lengthwise (L) direction, with the two outermost boundary lines opposing each other in the lengthwise (L) direction of coil component 1000 as shown in the cross-sectional image. Alternatively, the length of coil assembly 1000 may refer to the arithmetic average of at least three dimensions of a plurality of line segments connecting two outermost boundary lines of coil assembly 1000 and parallel to the length direction (L), the two outermost boundary lines being opposite in the length direction (L) of coil assembly 1000 as shown in the cross-sectional image. In this case, the plurality of line segments parallel to the length direction (L) may be equally spaced from one another in the thickness direction (T), but the present disclosure is not limited thereto.

[0033] Based on an optical microscope image or scanning electron microscope (SEM) image of a lengthwise (L)-thicknesswise (T) cross-section taken from the center of coil component 1000 in the widthwise (W) direction, the thickness of coil component 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of coil component 1000 and parallel to the thicknesswise (T) direction, the two outermost boundary lines being opposite in the thicknesswise (T) direction as shown in the cross-sectional image. Alternatively, the thickness of coil component 1000 may refer to the minimum value of the dimensions of a plurality of line segments connecting two outermost boundary lines of coil component 1000 and parallel to the thicknesswise (T) direction, the two outermost boundary lines being opposite in the thicknesswise (T) direction as shown in the cross-sectional image. Alternatively, the thickness of coil component 1000 may refer to the arithmetic average of at least three dimensions of a plurality of line segments connecting two outermost boundary lines of coil component 1000 and parallel to the thickness direction (T), the two outermost boundary lines being opposite to each other in the thickness direction (T) as shown in the cross-sectional image. In this case, the plurality of line segments parallel to the thickness direction (T) may be equally spaced from each other in the length direction (L), but the present disclosure is not limited thereto.

[0034] Based on an optical microscope image or scanning electron microscope (SEM) image of a length (L)-width (W) cross-section taken from the center of coil component 1000 in the thickness direction (T), the width of coil component 1000 may refer to the maximum value of the dimensions of a plurality of line segments connecting the two outermost boundary lines of coil component 1000 and parallel to the width direction (W), the two outermost boundary lines being opposite in the width direction (W) as shown in the cross-sectional image. Alternatively, the width of coil component 1000 may refer to the minimum value of the dimensions of a plurality of line segments connecting the two outermost boundary lines of coil component 1000 and parallel to the width direction (W), the two outermost boundary lines being opposite in the width direction (W) as shown in the cross-sectional image. Alternatively, the width of coil component 1000 may refer to the arithmetic average of at least three dimensions of a plurality of line segments connecting the two outermost boundary lines of coil component 1000 and parallel to the width direction (W), the two outermost boundary lines being opposite in the width direction (W) as shown in the cross-sectional image. In this case, the plurality of line segments parallel to the width direction (W) may be equally spaced from each other in the length direction (L), but the present disclosure is not limited thereto.

[0035] Alternatively, each of the length, width, and thickness of coil assembly 1000 can be measured using a micrometer measurement method. The micrometer measurement method can be performed using a micrometer with gauge repeatability and reproducibility (R&R) by setting a zero point, inserting coil assembly 1000 according to this embodiment between the tips of the micrometer, and rotating the measuring rod of the micrometer. On the other hand, when measuring the length of coil assembly 1000 using the micrometer measurement method, the length of coil assembly 1000 can refer to a value measured once or the arithmetic mean of values ​​measured multiple times. This also applies to the width and thickness of coil assembly 1000.

[0036] The body 100 may include an insulating resin and a magnetic material. Specifically, the body 100 may be formed by laminating one or more magnetic composite sheets in which a magnetic material is dispersed in the resin. The magnetic material may be ferrite or magnetic metal particles.

[0037] The ferrite may be, for example, at least one of spinel ferrite (such as Mg-Zn, Mn-Zn, Mn-Mg, Cu-Zn, Mg-Mn-Sr, Ni-Zn, etc.), hexagonal ferrite (such as Ba-Zn, Ba-Mg, Ba-Ni, Ba-Co and Ba-Ni-Co, etc.), garnet ferrite (such as Y-type ferrite, etc.) and Li-based ferrite.

[0038] The magnetic metal particles may include one or more selected from the group consisting of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), boron (B), zirconium (Zr), hafnium (Hf), phosphorus (P), and nickel (Ni). For example, the magnetic metal particles may be at least one of pure iron particles, Fe-Si alloy particles, Fe-Si-Al alloy particles, Fe-Ni alloy particles, Fe-Ni-Mo alloy particles, Fe-Ni-Mo-Cu alloy particles, Fe-Co alloy particles, Fe-Ni-Co alloy particles, Fe-Cr alloy particles, Fe-Cr-Si alloy particles, Fe-Si-Cu-Nb alloy particles, Fe-Ni-Cr alloy particles, and Fe-Cr-Al alloy particles.

[0039] The magnetic metal particles may include amorphous and / or crystalline particles. For example, the magnetic metal particles may be Fe-Si-B-Cr based amorphous alloy particles, but are not necessarily limited thereto. The ferrite and magnetic metal particles may have an average diameter of about 0.1 μm to about 30 μm, but the present disclosure is not limited thereto.

[0040] The body 100 may include different types (eg, two or more types) of magnetic materials dispersed in a resin. In this case, different types of magnetic materials refer to magnetic materials dispersed in the resin that are distinguished from each other by any one of average diameter, composition, crystallinity, and shape.

[0041] Furthermore, the following description will be based on the premise that the magnetic material is magnetic metal particles, but the present disclosure is not limited to the body 100 having only a structure in which magnetic metal particles are dispersed in an insulating resin.

[0042] The insulating resin may include epoxy resin, polyimide, liquid crystal polymer, etc., alone or in combination, but is not limited thereto.

[0043] Reference Figure 3 and Figure 5 , the body 100 includes a core 110 that penetrates the support member 200 and the coil 300. The core 110 may be disposed in a central region of the innermost turn of the coil 300 (ie, a central winding region of the coil 300).

[0044] Reference Figure 1 and Figure 2 The core 110 may be formed by filling a through hole H penetrating the center of the coil 300 and the center of the support member 200 with a magnetic composite sheet including a magnetic material, but the present disclosure is not limited thereto.

[0045] The support member 200 may be provided inside the body 100 and may have one surface and another surface facing each other. The support member 200 is a component supporting the coil 300.

[0046] Reference Figure 2 and Figure 3 , a central portion of the support member 200 may be removed through a trimming process to form a through hole H, and the core 110 may be disposed in the through hole H. Here, the through hole H formed in the support member 200 may be formed in a shape corresponding to the shape of the innermost turn of the coil 300 .

[0047] Support member 200 can be formed using an insulating material, including a thermosetting insulating resin (such as epoxy resin), a thermoplastic insulating resin (such as polyimide), or a photosensitive insulating resin. Alternatively, support member 200 can be formed using an insulating material prepared by impregnating the insulating resin with a reinforcing material (such as glass fiber or an inorganic filler). For example, support member 200 may include prepreg, Ajinomoto built-up film (ABF), FR-4, bismaleimide triazine (BT) resin, photosensitive dielectric (PID), etc., but the present disclosure is not limited thereto.

[0048] As the inorganic filler, at least one selected from the group consisting of silica (SiO2), alumina (Al2O3), silicon carbide (SiC), barium sulfate (BaSO4), talc, clay, mica powder, aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium carbonate (CaCO3), magnesium carbonate (MgCO3), magnesium oxide (MgO), boron nitride (BN), aluminum borate (AlBO3), barium titanate (BaTiO3) and calcium zirconate (CaZrO3) can be used.

[0049] When the support member 200 is formed of an insulating material including a reinforcing material, the support member 200 can provide better rigidity. When the support member 200 is formed of an insulating material that does not include glass fiber, it can be beneficial to reduce the thickness of the coil assembly 1000 according to an embodiment of the present disclosure. In addition, based on the main body 100 having the same size, the volume occupied by the coil 300 and / or the magnetic metal particles can be increased, thereby improving the component characteristics. When the support member 200 is formed of an insulating material including a photosensitive insulating resin, since the number of processes for forming the coil 300 is reduced, it can be beneficial to reduce production costs, and the vias 321 and 322 can be formed finely.

[0050] The thickness of the support member 200 may be, for example, greater than or equal to 10 μm and less than or equal to 50 μm, but is not limited thereto.

[0051] The coil 300 is disposed inside the body 100 and exhibits characteristics of the coil component 1000. For example, when the coil component 1000 according to this embodiment is used as a power inductor, the coil 300 stores an electric field as a magnetic field to maintain an output voltage, thereby stabilizing power of an electronic device.

[0052] The coil component 1000 according to the present embodiment may include a coil 300 disposed within the body 100 and supported by the support member 200. The coil 300 may include at least one turn wound around the core 110.

[0053] Reference Figures 1 to 5 The coil 300 of this embodiment may include a first coil portion 311 and a second coil portion 312 , a first via 321 , a first lead portion 331 and a second lead portion 332 , an auxiliary lead portion 340 , and a second via 322 .

[0054] In detail, the first coil portion 311, the first lead-out portion 331 extending from the first coil portion 311, and the second lead-out portion 332 spaced apart from the first coil portion 311 may be arranged on one surface of the support member 200 facing the first surface 101 of the main body 100, and the second coil portion 312 and the auxiliary lead-out portion 340 extending from the second coil portion 312 may be arranged on the other surface of the support member 200 facing the second surface 102 of the main body 100.

[0055] In addition, the first and second coil parts 311 and 312 may be connected through the first via hole 321 penetrating the support member 200 , and the sub-lead-out part 340 and the second lead-out part 332 may be connected through the second via hole 322 penetrating the support member 200 .

[0056] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 5 , each of the first coil part 311 and the second coil part 312 may have at least one turn centered on the core 110. Each of the first coil part 311 and the second coil part 312 may have a planar spiral shape, but is not limited thereto.

[0057] The first coil portion 311 may be disposed on one surface of the support member 200 and may form at least one turn around the core 110. The second coil portion 312 may be disposed on the other surface of the support member 200 and may form at least one turn around the core 110.

[0058] Reference Figure 2 and Figure 5 The coil 300 may include a first via hole 321 connecting the first coil portion 311 disposed on one surface of the support member 200 and the second coil portion 312 disposed on the other surface of the support member 200. The first via hole 321 may be provided to penetrate the support member 200, but the present disclosure is not limited thereto.

[0059] The first via hole 321 may electrically connect the first coil portion 311 and the second coil portion 312 provided on both surfaces of the support member 200. Figure 1direction, a lower surface of the first via 321 may be connected to an end of the innermost turn of the first coil part 311 , and an upper surface of the first via 321 may be connected to an end of the innermost turn of the second coil part 312 .

[0060] Reference Figures 1 to 3 The coil 300 of this embodiment may include a first lead-out portion 331 extending from the outermost turn of the first coil portion 311 and a sub-lead-out portion 340 extending from the outermost turn of the second coil portion 312 .

[0061] The first lead-out portion 331 may be disposed on one surface of the support member 200 , extend from the outermost turn of the first coil part 311 , and be connected to the first external electrode 510 through a first connection portion 410 (to be described later).

[0062] In addition, the sub-lead-out portion 340 may be disposed on the other surface of the support member 200 , extend from the outermost turn of the second coil part 312 , and be connected to the second external electrode 520 through a second via 322 and a second connection portion 420 (to be described later).

[0063] Reference Figure 2 and Figure 3 The second via 322 can connect the auxiliary lead portion 340 and the second lead portion 332 to each other. Since the auxiliary lead portion 340 and the second lead portion 332 are separated from each other by the support member 200, the auxiliary lead portion 340 and the second lead portion 332 can be connected to each other through the second via 322 that penetrates the support member 200.

[0064] Here, the second via 322 may be integrally formed with the sub-lead-out portion 340. Here, the second via 322 and the sub-lead-out portion 340 being integrally formed may mean that the second via 322 and the sub-lead-out portion 340 are formed together in the same process without a boundary surface between the two components, but the present disclosure is not limited thereto.

[0065] Reference Figure 2 and Figure 3 , for example, when a signal is input to the first external electrode 510 , the input signal may be applied to the coil 300 through the first connection portion 410 , and may be output to the second external electrode 520 through the second connection portion 420 .

[0066] In more detail, the signal input to the first external electrode 510 can be output to the second external electrode 520 through the first connection part 410, the first lead part 331, the first coil part 311, the first via 321, the second coil part 312, the sub-lead part 340, the second via 322 and the second lead part 332.

[0067] Therefore, the coil 300 as a whole may function as one coil located between the first connection portion 410 and the second connection portion 420 .

[0068] At least one of the first and second coil parts 311 and 312 , the first and second via holes 321 and 322 , the first and second lead-out parts 331 and 332 , and the sub-lead-out part 340 may include at least one conductive layer.

[0069] For example, when the first coil portion 311, the first lead-out portion 331, the first via 321, the second lead-out portion 332 and the second via 322 are formed by plating on one surface of the support member 200, each of the first coil portion 311, the first lead-out portion 331, the first via 321, the second lead-out portion 332 and the second via 322 may include a seed layer and a plating layer.

[0070] In this case, the electroplating layer may have a single-layer structure or a multi-layer structure. The electroplating layer having a multi-layer structure may be formed into a conformal film structure in which one electroplating layer is formed along the surface of another electroplating layer, or may be formed into a shape in which one electroplating layer is stacked on only one surface of another electroplating layer. The seed layer may be formed by an electroless plating method or a vapor deposition method (such as a sputtering method).

[0071] The seed layer of each of the first coil portion 311, the first lead-out portion 331, the first via hole 321, the second lead-out portion 332, and the second via hole 322 may be integrally formed so as not to form a boundary therebetween, but the present disclosure is not limited thereto. The electroplating layer of each of the first coil portion 311, the first lead-out portion 331, the first via hole 321, the second lead-out portion 332, and the second via hole 322 may be integrally formed so as not to form a boundary therebetween, but the present disclosure is not limited thereto.

[0072] Each of the first coil portion 311, the first lead portion 331, the first via 321, the second lead portion 332 and the second via 322 may be formed using a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti) and / or alloys thereof, but the present disclosure is not limited thereto.

[0073] Reference Figures 1 to 4 , the coil component 1000 according to the present embodiment may include connection parts 410 and 420 connecting the first and second external electrodes 510 and 520 to the coil 300 , respectively.

[0074] The connecting portions 410 and 420 are provided in the body 100 and are components for electrical connection between the coil 300 and the external electrodes 510 and 520. Compared with the "L"-shaped electrodes provided on the third surface 103 and the fourth surface 104 of the body 100 and extending to the first surface 101, the connecting portions 410 and 420 can have a reduced DC resistance component (R dc ) effect.

[0075] The connection parts 410 and 420 may include one surface in contact with the coil 300 and the other surface in contact with the external electrodes 510 and 520 .

[0076] In addition, the connecting parts 410 and 420 may include a side surface connecting one surface and the other surface thereof, and may have a cylindrical shape. However, the present disclosure is not limited thereto, and the connecting parts 410 and 420 may be formed in various shapes, such as a tapered shape with a cross-sectional area gradually widening toward the bottom, a tapered shape with a cross-sectional area gradually narrowing toward the bottom, a prism shape, etc.

[0077] The connection portions 410 and 420 of this embodiment may be formed by electroplating and may be formed using a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti) and / or alloys thereof, but the present disclosure is not limited thereto.

[0078] In the coil 1000 according to the present embodiment, the connection parts 410 and 420 (connecting the external electrodes 510 and 520 in the first direction (T)) and the coil 300 may be formed separately, and then the coil 300 and the connection parts 410 and 420 may be welded.

[0079] Therefore, the connection parts 410 and 420 of the present embodiment may include welded parts 411 and 421 formed at the ends thereof in contact with the coil 300. Here, the welded parts 411 and 421 may correspond to the areas formed when the connection parts 410 and 420 and the coil 300 are welded by resistance welding, laser welding, ultrasonic welding, etc., and for convenience of explanation, the boundary lines of the welded parts 411 and 421 within the connection parts 410 and 420 are indicated by dotted lines.

[0080] Reference Figure 3 The first connection portion 410 may connect the first external electrode 510 and the first lead portion 331 in the body 100 , and the first connection portion 410 may include a first welding portion 411 formed at an end portion contacting the first lead portion 331 .

[0081] In addition, the second connection portion 420 may connect the second external electrode 520 and the second lead-out portion 332 in the body 100 , and may include a second welding portion 421 formed at an end portion contacting the second lead-out portion 332 .

[0082] Furthermore, the welded portions 411 and 421 of the present embodiment may have partially deformed shapes due to heat and pressure when welded to the coil 300 by resistance welding, laser welding, ultrasonic welding, etc. This will be explained in detail below.

[0083] Figure 4 It shows Figure 3 An enlarged view of region A in the middle shows that the second connection portion 420 is in contact with the second lead portion 332 in region A.

[0084] Reference Figure 3 and Figure 4 The second connection portion 420 may include a second welding portion 421 formed at an end portion contacting the second lead-out portion 332 , and at least a portion of the second welding portion 421 may be embedded in the second lead-out portion 332 .

[0085] Similarly, the first connection portion 410 may include a first welding portion 411 formed at an end portion contacting the first lead-out portion 331 , and at least a portion of the first welding portion 411 may be embedded in the first lead-out portion 331 .

[0086] As an example, when the welded portions 411 and 421 and the lead-out portions 331 and 332 are welded by resistance welding, at least a portion of the welded portions 411 and 421 may be embedded in the lead-out portions 331 and 332 of the coil 300 according to heat generated by current flow and pressure in the first direction (T).

[0087] Reference Figure 4 , at least a portion of the upper surface of the second welding portion 421 may expand due to the pressure in the first direction (T), and accordingly, the at least a portion may protrude toward the body 100 .

[0088] Similarly, the first welding portion 411 may also have at least a portion protruding toward the main body 100 .

[0089] Therefore, if Figure 3 As shown, based on an optical microscope image or a scanning electron microscope (SEM) image of a first direction (T)-second direction (L) cross-section taken from a central portion of the coil component 1000 in the third direction (W) according to the present embodiment, at least a portion of the fusion bonds 411 and 412 may protrude toward the body 100 along the second direction (L).

[0090] As an example, when welded portions 411 and 421 and lead portions 331 and 332 are welded by resistance welding, at least a portion of welded portions 411 and 421 may protrude toward main body 100 due to heat generated by the flow of current and pressure in the first direction (T). As an example, protruding toward main body 100 may mean protruding toward a central portion of main body 100 in the second direction (L) and / or protruding toward at least one of the wall surfaces of main body 100.

[0091] Reference Figure 3 and Figure 4 The welded portions 411 and 412 may form an interface with the coil 300. Specifically, the first welded portion 411 may form an interface with the first lead-out portion 311, and the second welded portion 421 may form an interface with the second lead-out portion 332.

[0092] Furthermore, traces of metal particles being melted by heat, thereby changing the crystal structure, can be observed at the interface between the first weld portion 411 and the first lead-out portion 331 and the interface between the second weld portion 412 and the second lead-out portion 332 .

[0093] In addition, an uneven surface US may be included in the interface between the welded parts 411 and 421 and the coil 300 of the present embodiment.

[0094] Reference Figure 4 , an irregular uneven surface US may be included in the interface where the second welding portion 421 contacts the second lead-out portion 332. For example, when the second welding portion 421 and the second lead-out portion 332 are welded by resistance welding, the irregular uneven surface US may be formed in the interface between the second welding portion 421 and the second lead-out portion 332 due to heat generated according to the flow of current and pressure in the first direction (T).

[0095] In the coil component 1000 according to the present embodiment, the contact area between the welded parts 411 and 421 and the coil 300 can be increased due to the uneven surface US, thereby increasing the physical bonding force and the electrical connection reliability, and also reducing the DC resistance component (R dc ).

[0096] Reference Figure 3 、 Figure 4 and Figure 5 The coil component 1000 according to the present embodiment may further include an insulating film IF. The insulating film IF may entirely cover the support member 200 and the coil 300 , and may extend to cover at least a portion of the connection portions 410 and 420 .

[0097] Specifically, the insulating film IF may be provided between the support member 200 and the body 100, between the coil 300 and the body 100, and between the connection portions 410 and 420 and the body 100. The insulating film IF may be formed along a surface of the support member 200 on which the coil portions 311 and 312, the lead-out portions 331 and 332, and the connection portions 410 and 420 are provided, but the present disclosure is not limited thereto.

[0098] The insulating film IF may be filled between adjacent turns in each of the first coil portion 311 and the second coil portion 312, and may be filled between each of the first lead-out portion 331 and the second lead-out portion 332 and the first coil portion 311, and between the auxiliary lead-out portion 340 and the second coil portion 312 to insulate the coil turns.

[0099] The insulating film IF is used to insulate the coil 300 from the main body 100 and / or the connection portions 410 and 420 from the main body 100. It may comprise a known insulating material (such as parylene), but the present disclosure is not limited thereto. As another example, the insulating film IF may comprise an insulating material (such as epoxy resin instead of parylene). The insulating film IF may be formed by vapor deposition, but the present disclosure is not limited thereto. As another example, the insulating film IF may be formed by laminating and curing an insulating film on the support member 200 on which the coil 300 is disposed. Alternatively, the insulating film IF may be formed by applying and curing an insulating paste on both surfaces of the support member 200 on which the coil 300 is disposed. Furthermore, the insulating film IF may be omitted in this embodiment. Specifically, if the main body 100 has sufficient resistance at the designed operating current and operating voltage of the coil assembly 1000 according to this embodiment, the insulating film IF may be omitted in this embodiment.

[0100] Reference Figures 1 to 3 , the first and second external electrodes 510 and 520 may be disposed to be spaced apart from each other on the first surface 101 of the body 100 and connected to the coil 300 through the first and second connection portions 410 and 420 , respectively.

[0101] Reference Figure 3 , the external electrodes 510 and 520 may be formed in a multi-layer structure.

[0102] For example, the external electrodes 510 and 520 may include first layers 511 and 521 disposed on the body 100 and second layers 512 and 522 disposed on the first layers 511 and 521. In addition, the external electrodes 510 and 520 may further include third layers 513 and 523 disposed on the second layers 512 and 522.

[0103] At least one of the second layers 512 and 522 and the third layers 513 and 523 may be formed to cover the first layers 511 and 521 , but the present disclosure is not limited thereto.

[0104] The first layers 511 and 521 may be copper (Cu) plated layers or conductive resin layers including conductive particles including at least one of copper (Cu) and silver (Ag) and insulating resin.

[0105] The second layers 512 and 522 may be plated layers including nickel (Ni), and the third layers 513 and 523 may be plated layers including tin (Sn), but the present disclosure is not limited thereto. The second layers 512 and 522 and the third layers 513 and 523 may also be entirely formed in the form of an alloy of nickel (Ni) and tin (Sn).

[0106] The first and second external electrodes 510 and 520 may be formed by a vapor deposition method such as a sputtering method and / or a plating method, but the present disclosure is not limited thereto.

[0107] The first and second external electrodes 510 and 520 may be formed using a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), alloys thereof, etc., but the present disclosure is not limited thereto.

[0108] Reference Figures 3 to 5 , the coil component 1000 according to the present embodiment may include insulating layers 610 and 620 covering the body 100 and exposing the external electrodes 510 and 520 .

[0109] Specifically, the first insulating layer 610 of the present embodiment may cover a portion of the first surface 101 of the body 100 and may be disposed to expose the first and second external electrodes 510 and 520 .

[0110] In addition, the second insulating layer 620 of this embodiment may be provided to cover at least a portion of at least one of the second surface 102 , the third surface 103 , the fourth surface 104 , the fifth surface 105 , and the sixth surface 106 of the body 100 .

[0111] Reference Figure 3 , both end surfaces of the first insulating layer 610 may be adjacent to inner side surfaces of the first layers 511 and 521 in the second direction (L), respectively.

[0112] In the present embodiment, the second layers 512 and 522 may respectively overlap a portion of the first insulating layer 610 in the first direction (T) and may respectively cover outer side surfaces of the first layers 511 and 521 in the second direction (L).

[0113] Reference Figure 5, the first insulating layer 610 and the second insulating layer 620 of this embodiment may be formed in different processes to form a boundary therebetween, and in the second insulating layer 620, the respective insulating layers arranged on the second surface 102, the third surface 103, the fourth surface 104, the fifth surface 105 and the sixth surface 106 of the body 100 may be formed in the same process to be formed integrally without boundaries, but the present disclosure is not limited thereto.

[0114] The first insulating layer 610 and the second insulating layer 620 may be formed by a method such as printing, vapor deposition, spraying, or film lamination, but the present disclosure is not limited thereto.

[0115] The first insulating layer 610 and the second insulating layer 620 may include thermoplastic resins (such as polystyrene resins, vinyl acetate resins, polyester resins, polyethylene resins, polypropylene resins, polyamide resins, rubber resins, acrylic resins, etc.), thermosetting resins (such as phenol resins, epoxy resins, polyurethane resins, melamine resins, alkyd resins, etc.), photosensitive insulating resins, polyparaxylene, SiO x or SiN x The first insulating layer 610 and the second insulating layer 620 may further include an insulating filler such as an inorganic filler, but the present disclosure is not limited thereto.

[0116] A manufacturing process of the coil component according to the first embodiment.

[0117] Figure 6 、 Figure 7 and Figure 8 10 is a diagram schematically illustrating a manufacturing process of the coil component 1000 according to the first embodiment of the present disclosure.

[0118] Reference Figure 6 , a through hole H in which the core 110 will be set and a via hole in which the vias 321 and 322 will be set can be formed in the support member 200, and the first coil portion 311 and the second coil portion 312, the first via hole 321 and the second via hole 322, the first lead-out portion 331 and the second lead-out portion 332 and the auxiliary lead-out portion 340 can be formed by plating.

[0119] Next, a separate core DC having a copper foil CF disposed on one surface thereof may be prepared, and the connection parts 410 and 420 may be formed by plating copper (Cu) on an upper surface of the copper foil CF.

[0120] Next, the lead-out portions 331 and 332 and the connection portions 410 and 420 may be welded using resistance welding, laser welding, ultrasonic welding, or the like.

[0121] Welded portions 411 and 421 partially deformed by heat and pressure may be formed at ends of the connection portions 410 and 420 contacting the lead-out portions 331 and 332 .

[0122] Next, an insulating film IF may be formed to entirely cover the coil 300 and the connecting portions 410 and 420. The insulating film IF of the present disclosure may include parylene, but the present disclosure is not limited thereto. Furthermore, a non-adhesive parylene insulating film IF may be formed on the copper foil CF, which has the advantage of facilitating the separation process when separating the separate core DC from the main body 100.

[0123] Next, refer to Figure 7 , in a state in which the coil 300 , the connection parts 410 and 420 , and the split cores are DC-connected, the body 100 may be formed by stacking and solidifying magnetic sheets.

[0124] Next, the separate core DC including the copper foil CF may be removed to expose the first surface 101 of the body 100 and the other surfaces of the connection parts 410 and 420. In this case, a portion of the insulation film IF having no bonding strength with the body 100 may also be removed from the first surface 101 of the body 100.

[0125] Next, a first insulating layer 610 may be disposed on the remaining area of ​​the first surface 101 of the body 100 except for areas where the external electrodes 510 and 520 will be disposed. The first insulating layer 610 may be formed using a screen printing method, but the present disclosure is not limited thereto.

[0126] Reference Figure 8 , the foam tape FT may be disposed on the first surface 101 of the body 100 to cover the first insulating layer 610 .

[0127] In addition, the foam tape FT is a component that facilitates batch printing and partial removal of the second insulating layer 620 .

[0128] Next, the second insulating layer 620 may be provided to entirely cover the second, third, fourth, fifth, and sixth surfaces 102, 103, 104, 105, and 106 of the body 100 and the foam tape FT. The second insulating layer 620 may be formed by a roll coating method, but the present disclosure is not limited thereto.

[0129] Next, by foaming and removing the foam tape FT, only regions of the surface of the body 100 where the external electrodes 510 and 520 are to be disposed may be exposed.

[0130] Finally, the first layers 511 and 521 , the second layers 512 and 522 , and the third layers 513 and 523 of the external electrodes 510 and 520 may be formed.

[0131] Second embodiment.

[0132] Figure 9 The coil assembly 2000 according to the second embodiment of the present disclosure is schematically shown. Figure 3 Schematic diagram of .

[0133] Compare Figure 9 and Figure 3 , Figure 9 and Figure 3 The difference is that the body interface BI perpendicular to the first direction (T) is formed inside the body 100, the insulating film IF is partially opened and does not cover the connecting parts 410 and 420, and the first layers 511 and 521 of the external electrodes 510 and 520 are buried inside the body 100.

[0134] Therefore, when describing this embodiment, only the following structures that are different from those of the first embodiment will be described: the body interface BI is formed inside the body 100, the insulating film IF is opened, and the first layers 511 and 521 of the external electrodes 510 and 520 are buried inside the body 100. For the remaining components of this embodiment, the description of the first embodiment of the present disclosure can be applied as is.

[0135] Reference Figure 9 , the coil component 2000 according to the second embodiment of the present disclosure may include a body interface BI formed inside the body 100 and perpendicular to the first direction (T).

[0136] The body interface BI may be formed to be lower than one surface of the connection parts 410 and 420 in contact with the coil 300. That is, based on the inner surfaces of the external electrodes 510 and 520 in contact with the body 100, the height Hb of the body interface BI may be formed to be lower than the height Hc of the upper surfaces of the connection parts 410 and 420.

[0137] In this case, based on an optical microscope image or a scanning electron microscope (SEM) image of a lengthwise (L)-thicknesswise (T) cross section taken from the center of coil component 2000 in the widthwise (W) direction, the height Hb of body interface BI may refer to the arithmetic average of at least three dimensions of a plurality of line segments connecting body interface BI shown in the cross-sectional image with the innermost surface of the external electrode and parallel to the thicknesswise (T) direction. In this case, the plurality of line segments parallel to the thicknesswise (T) direction may be equally spaced from one another in the lengthwise (L) direction, but the present disclosure is not limited thereto.

[0138] Furthermore, the height Hc of the upper surfaces of the connecting portions 410 and 420 may refer to the arithmetic mean of at least three dimensions of a plurality of line segments parallel to the thickness direction (T), the plurality of line segments being obtained by setting the interface of the connecting portions 410 and 420 shown in the cross-sectional image, which contacts the coil 300, as a center line, and connecting the center line with the innermost surfaces of the external electrodes 510 and 520. In this case, the plurality of line segments parallel to the thickness direction (T) may be equally spaced from one another in the length direction (L), but the present disclosure is not limited thereto.

[0139] The body interface BI of this embodiment may be formed in the region between the coil 300 and the first surface 101, which may correspond to the fact that the process for forming the body 100 is performed in two stages. The detailed process sequence will be described later.

[0140] Reference Figure 9 Since the connection parts 410 and 420 of this embodiment are not covered by the insulating film IF, the side surfaces of the connection parts 410 and 420 connecting the upper surface and the lower surface of the connection parts 410 and 420 can directly contact the body 100. In this embodiment, it is preferred that the magnetic metal particles included in the body 100 are insulated and coated.

[0141] In the coil component 2000 according to the present embodiment, the insulating film IF may be partially opened to expose at least a portion of the welded portions 411 and 421 to the body 100 .

[0142] The external electrodes 510 and 520 of this embodiment may be disposed such that the first layers 511 and 521 contact the lower surfaces of the connection parts 410 and 420 and are buried in the body 100 .

[0143] Specifically, the first layers 511 and 521 of the present embodiment may have an inner surface in contact with the body 100 and an outer surface opposite to the inner surface, and the outer surface may be provided so as not to protrude beyond the first surface 101 of the body 100. That is, the outer surfaces of the first layers 511 and 521 of the external electrodes 510 and 520 may be recessed inward relative to the first surface 101 of the body 100 or be at the same height as the first surface 101 of the body 100.

[0144] In the present embodiment, the third layers 513 and 523 of the external electrodes 510 and 520 may cover inner side surfaces of the second layers 512 and 522 in the second direction (L).

[0145] In addition, both end surfaces of the first insulating layer 610 may be respectively adjacent to the inner side surfaces of the third layers 513 and 523 in the second direction (L). As an example, the lower surfaces of the first layers 511 and 521 may be formed to be in contact with the second layers 512 and 522 and the third layers 513 and 523, and the inner side surfaces of the first layers 511 and 521 and the inner side surfaces of the third layers 513 and 523 may be formed to be coplanar with each other in the first direction (T). Therefore, the coil component 2000 according to the present embodiment may have a shape in which the outermost surfaces of the external electrodes 510 and 520 do not protrude outside the first insulating layer 610 .

[0146] Compared with the first embodiment, in the coil component 2000 according to the present disclosure, since the magnetic material can be filled in the area obtained by removing the insulating film IF within the main body 100, and some areas of the external electrodes 510 and 520 can be buried in the main body 100, a larger effective volume can be ensured within a limited size, and the inductance characteristics can be improved.

[0147] According to the second embodiment, a process for manufacturing a coil component is provided.

[0148] Figure 10 、 Figure 11 and Figure 12 is a diagram schematically illustrating a manufacturing process of a coil component according to a second embodiment of the present disclosure.

[0149] Figure 10 、 Figure 11 and Figure 12 The reference numerals of the components shown in Figure 6 、 Figure 7 and Figure 8 The components shown in FIG. 1 have the same reference numerals, and some reference numerals are omitted for ease of understanding.

[0150] Reference Figure 10 , a through hole H in which the core 110 will be set and a via hole in which the vias 321 and 322 will be set can be formed in the support member 200, and the first coil portion 311 and the second coil portion 312, the first via hole 321 and the second via hole 322, the first lead-out portion 331 and the second lead-out portion 332 and the auxiliary lead-out portion 340 can be formed by plating.

[0151] The insulating film IF may be formed to entirely cover the coil 300 and the support member 200 .

[0152] Next, the first layers 511 and 521 of the outer electrodes 510 and 520 may be formed by partially removing the copper foil CF (e.g., Figure 6 As shown in FIG, the first layers 511 and 521 may be pre-formed, and the connection portions 410 and 420 may be formed by copper (Cu) plating on the first layers 511 and 521 .

[0153] Next, the region of the insulating film IF that entirely covers the coil 300 and the support member 200 to be connected to the connection portions 410 and 420 may be removed in advance, and a portion of the lower surface of the first lead portion 331 and a portion of the lower surface of the second lead portion 332 may be exposed.

[0154] Next, a portion of the body 100 may be formed by stacking and solidifying magnetic sheets on the first layers 511 and 521 and the connection parts 410 and 420 provided on the separate cores DC.

[0155] Therefore, the first layers 511 and 521 of the external electrodes 510 and 520 of this embodiment may be buried in the body 100 .

[0156] The height of the body 100 formed at this time may correspond to the height of the body interface BI of the coil component 2000 of the present embodiment, and may be formed at a height lower than that of the upper surfaces of the connection parts 410 and 420 .

[0157] Furthermore, in the present embodiment, when a sheet through which the connection parts 410 and 420 can penetrate is used as a magnetic sheet to form a portion of the body 100 , the connection parts 410 and 420 can be prevented from being deformed when the magnetic sheet is pressed.

[0158] Next, the lead-out portions 331 and 332 and the connection portions 410 and 420 may be welded using resistance welding, laser welding, ultrasonic welding, or the like.

[0159] Welded portions 411 and 421 partially deformed by heat and pressure may be formed at ends of the connection portions 410 and 420 contacting the lead-out portions 331 and 332 .

[0160] Reference Figure 11 , with the coil 300 , the connection parts 410 and 420 , and the separate cores DC-connected, the magnetic sheets may be stacked and solidified from top to bottom in the remaining area of ​​the body 100 (another portion of the body 100 ), thereby completing the body 100 .

[0161] In this case, the main interface BI can be Figure 10 A portion of the body 100 formed earlier in the Figure 11 It is formed between another portion of the body 100 that is formed later.

[0162] Next, the separate core DC may be removed to expose the first surface 101 of the body 100 and the first layers 511 and 521 of the external electrodes 510 and 520 .

[0163] Next, a first insulating layer 610 may be disposed on the remaining area of ​​the first surface 101 of the body 100 except for the area where the external electrodes 510 and 520 are disposed. The first insulating layer 610 may be formed using a screen printing method, but the present disclosure is not limited thereto.

[0164] Reference Figure 12 , the foam tape FT may be provided to cover the first insulating layer 610 and the first layers 511 and 521 of the external electrodes 510 and 520 on the first surface 101 of the body 100 .

[0165] Furthermore, the foam tape FT is configured to facilitate batch printing and partial removal of the second insulating layer 620 .

[0166] Next, the second insulating layer 620 may be disposed to entirely cover the second, third, fourth, fifth, and sixth surfaces 102, 103, 104, 105, and 106 of the body 100 and the foam tape FT. The second insulating layer 620 may be formed by a roll coating method, but the present disclosure is not limited thereto.

[0167] Next, by foaming and removing the foam tape FT, only the region where the first layers 511 and 521 of the external electrodes 510 and 520 are disposed among the surfaces of the body 100 may be exposed.

[0168] Finally, the second layers 512 and 522 and the third layers 513 and 523 may be sequentially formed on the first layers 511 and 521 by plating, thereby completing the external electrodes 510 and 520 .

[0169] As described above, according to the embodiments of the present disclosure, the inductance characteristics and the saturation current (I sat ) characteristics can be improved by maximizing the effective volume within a coil assembly of limited size by connecting the coil and the external electrode within the body.

[0170] According to an embodiment of the present disclosure, by pre-forming a connecting portion (for connecting the coil to the external electrode) and then bonding it to the coil, process advantages such as preventing poor connection between the coil and the external electrode and preventing plating diffusion defects of the external electrode can be obtained.

[0171] While example embodiments have been shown and described above, it will be readily apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. A coil assembly, comprising: a body having a first surface and a second surface opposite to each other in a first direction; a coil disposed in the body; an external electrode, disposed on the first surface of the body; as well as a connecting portion, disposed in the main body to connect the coil and the external electrode, the connecting portion having one surface in contact with the coil and another surface in contact with the external electrode, The connecting portion includes a welding portion formed at an end portion in contact with the coil.

2. The coil assembly according to claim 1, wherein: At least a portion of the weld is embedded in the coil.

3. The coil assembly according to claim 1, wherein: At least a portion of the weld portion protrudes toward the body.

4. The coil assembly according to claim 1, wherein: An interface is formed between the welded portion and the coil.

5. The coil assembly according to claim 4, wherein: The interface includes a non-planar surface.

6. The coil assembly according to claim 1, further comprising: An insulating film covers the coil.

7. The coil assembly according to claim 6, wherein: The insulating film extends to cover at least a portion of the connecting portion.

8. The coil assembly according to claim 6, wherein: The connecting portion includes a side surface connecting the one surface and the other surface of the connecting portion, and The side surface of the connection portion is in contact with the body.

9. The coil assembly according to claim 6, wherein: The insulating film exposes at least a portion of the weld portion.

10. The coil assembly according to claim 8, wherein: The body includes a body interface perpendicular to the first direction.

11. The coil assembly according to claim 10, wherein: The body interface is located at a height lower than that of the one surface of the connection portion.

12. The coil assembly according to claim 1, wherein: The external electrode includes a first layer and a second layer disposed on the first layer, and the first layer is disposed on the body or buried in the body.

13. The coil assembly according to claim 12, wherein: The outer electrode further comprises: The third layer is arranged on the second layer.

14. The coil assembly according to claim 12, wherein: The first layer contacts the other surface of the connection portion and is buried in the body.

15. The coil assembly according to claim 12, wherein: The first layer has an inner surface in contact with the body and an outer surface opposite to the inner surface, and The outer surface of the first layer does not protrude beyond the first surface of the body.

16. The coil assembly according to claim 1, further comprising: A first insulating layer covers the first surface of the body and exposes the external electrode.

17. The coil assembly according to claim 16, further comprising: A second insulating layer covers the remaining surface of the body except the first surface of the body.

18. The coil assembly according to claim 16, wherein: The external electrode includes a first layer and a second layer disposed on the first layer, the first layer is disposed on the body, and An end surface of the first insulating layer abuts against an inner side surface of the first layer of the external electrode in a second direction perpendicular to the first direction.

19. The coil assembly according to claim 18, wherein: The second layer of the external electrode overlaps a portion of the first insulating layer in the first direction and covers an outer side surface of the first layer of the external electrode in the second direction.

20. The coil assembly according to claim 16, wherein: The external electrode includes a first layer, a second layer disposed on the first layer, and a third layer disposed on the second layer, the first layer is buried in the body, The third layer of the external electrode covers an inner side surface of the second layer in a second direction perpendicular to the first direction, and An end surface of the first insulating layer abuts against an inner side surface of the third layer in the second direction.

21. The coil assembly according to claim 1, wherein: The coil assembly further includes a supporting member disposed in the body, and the coil is disposed on the supporting member.

22. A method for manufacturing a coil assembly, the method comprising: forming a coil; forming a connection portion; The connection portion is welded to both ends of the coil to form welded portions at ends of the connection portion that are in contact with the coil.

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