Coil assembly

Abstract

The present invention provides a coil assembly comprising an insulating substrate; a coil portion disposed on at least one surface of the insulating substrate; and a body, wherein the insulating substrate and the coil portion are embedded in the body, and the body has an effective portion in which the coil portion is disposed and a covering portion disposed on the effective portion. The ratio of the thickness (T2) of the covering portion to the thickness (T1) of the insulating substrate satisfies 3 < T2 / T1 < 6, and the thickness (T2) of the covering portion satisfies 90 μm. <T2<120μm。

Description

[0001] This application is a divisional application of the invention patent application with the application date of December 06, 2019, the application number of 201911238902.8, and the title of "Coil Assembly". Technical Field

[0002] The present disclosure relates to a coil assembly. Background Art

[0003] An inductor (coil assembly) is a representative passive electronic component used in an electronic device together with a resistor and a capacitor.

[0004] As higher performance and smaller size in an electronic device are gradually achieved, the coil assembly is becoming thinner.

[0005] Even if the coil assembly is made thinner, there may be a limit in reducing the coil thickness of the coil assembly because the coil assembly ensures appropriate inductance and direct current (DC) resistance (Rdc).

[0006] Therefore, in terms of making the coil assembly thinner, research is being conducted to reduce at least one of the thickness of an external electrode other than the coil, the thicknesses of an upper covering portion and a lower covering portion respectively provided on the upper and lower portions of the coil, and the thickness of a support substrate for supporting the coil. Summary of the Invention

[0007] One aspect of the present disclosure is to provide a coil assembly that can ensure a large-capacity inductance and a low direct current (DC) resistance (Rdc) while having a small profile.

[0008] According to one aspect of the present disclosure, a coil assembly includes: an insulating substrate; a coil portion provided on at least one surface of the insulating substrate; and a body in which the insulating substrate and the coil portion are embedded, and the body has an effective portion in which the coil portion is provided and a covering portion provided on the effective portion. The ratio of the thickness (T2) of the covering portion to the thickness (T1) of the insulating substrate satisfies 3 < T2 / T1 < 6, and the thickness (T2) of the covering portion satisfies 90 μm < T2 < 120 μm.

[0009] According to another aspect of the present disclosure, a coil assembly includes: a body; an insulating substrate embedded in the body; and a coil portion provided at least on the upper surface of the insulating substrate. The ratio of the distance (T2) from the upper surface of the coil portion to the upper surface of the body to the thickness (T1) of the insulating substrate satisfies 3 < T2 / T1 < 6, and the distance (T2) from the upper surface of the coil portion to the upper surface of the body satisfies 90 μm < T2 < 120 μm. Brief Description of the Drawings

[0010] The above and other aspects, features and advantages of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 This is a schematic diagram illustrating a coil assembly according to an embodiment of the present disclosure;

[0012] Figure 2 It is along Figure 1 A cross-sectional view taken from line I-I'; and

[0013] Figure 3 It is along Figure 1 The cross-sectional view taken from line II-II'. Detailed Implementation

[0014] The terminology used in this disclosure is for describing particular embodiments and is not intended to limit the disclosure. Unless otherwise stated, singular terms include plural forms. The terms “comprising,” “including,” “constructed as,” etc., in this disclosure are used to indicate the presence of features, quantities, steps, operations, elements, parts, or combinations thereof, and do not preclude the possibility of combining or adding one or more additional features, quantities, steps, operations, elements, parts, or combinations thereof. Furthermore, the terms “set on,” “located on,” etc., may indicate that an element is located on or below an object, and do not necessarily mean that the element is located on the object with respect to the direction of gravity.

[0015] The terms “integrated into” and “combined into” can refer not only to components that are in direct and physical contact with each other, but also to structures in which other components are located between the components, allowing the components to also be in contact with other components.

[0016] For ease of description, the dimensions and thicknesses of the elements shown in the accompanying drawings are given as examples, and this disclosure is not limited thereto.

[0017] In the attached figures, the "L" direction is the first direction or the length (longitudinal) direction, the "W" direction is the second direction or the width direction, and the "T" direction is the third direction or the thickness direction.

[0018] In the following, a coil assembly according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. Referring to the drawings, the same or corresponding components may be designated by the same reference numerals, and repeated descriptions will be omitted.

[0019] In electronic devices, various types of electronic components can be used, and various types of coil assemblies can be used between electronic components to eliminate noise or for other purposes.

[0020] In other words, in electronic devices, coil assemblies can be used as power inductors, high-frequency (HF) inductors, ordinary ferrite beads, high-frequency (GHz) ferrite beads, common-mode filters, etc.

[0021] Figure 1 This is a schematic diagram illustrating a coil assembly according to an embodiment of the present disclosure. Figure 2 It is along Figure 1 The cross-sectional view taken from line I-I'. Figure 3 It is along Figure 1 The cross-sectional view taken from line II-II'.

[0022] Reference Figures 1 to 3 According to embodiments of the present disclosure, the coil assembly 1000 may include a body 100, an insulating substrate 200, a coil portion 300, and external electrodes 400 and 500, and may also include an insulating film 600.

[0023] The main body 100 can form the appearance of the coil assembly 1000 according to this embodiment, and the insulating substrate 200 and the coil portion 300 can be embedded in the main body 100.

[0024] The main body 100 can be formed into a whole with a hexahedral shape.

[0025] Reference Figures 1 to 3 The main body 100 may include a first surface 101 and a second surface 102 opposite to each other in the length direction L, a third surface 103 and a fourth surface 104 opposite to each other in the width direction W, and a fifth surface 105 and a sixth surface 106 opposite to each other in the thickness direction T. Each of the first surface 101, second surface 102, third surface 103, and fourth surface 104 of the main body 100 may correspond to a wall surface of the main body 100 that connects the fifth surface 105 and the sixth surface 106 of the main body 100. In the following, the two end surfaces of the main body 100 may refer to the first surface 101 and the second surface 102 of the main body 100, the two side surfaces of the main body 100 may refer to the third surface 103 and the fourth surface 104 of the main body 100, one surface of the main body 100 may refer to the sixth surface 106 of the main body 100, and the other surface of the main body 100 may refer to the fifth surface 105 of the main body 100. Furthermore, in the following, based on... Figures 1 to 3 In terms of direction, the upper surface of the main body 100 can refer to the fifth surface of the main body 100, and the lower surface of the main body 100 can refer to the sixth surface 106 of the main body 100.

[0026] The main body 100 may be configured such that the coil assembly 1000, in which the outer electrodes 400 and 500 (described later) are formed according to this embodiment, has a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.65 mm, but is not limited thereto. Optionally, the main body 100 may be configured such that the coil assembly 1000, in which the outer electrodes 400 and 500 (described later) are formed according to this embodiment, has a length of 2.0 mm, a width of 1.6 mm, and a thickness of 0.55 mm. Optionally, the main body 100 may be configured such that the coil assembly 1000, in which the outer electrodes 400 and 500 (described later) are formed according to this embodiment, has a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.55 mm. Optionally, the main body 100 may be configured such that the coil assembly 1000, in which the outer electrodes 400 and 500 (described later) are formed according to this embodiment, has a length of 1.2 mm, a width of 1.0 mm, and a thickness of 0.55 mm. Since the dimensions of the coil assembly 1000 according to this embodiment are merely illustrative, it is not possible to exclude cases where the dimensions are smaller than the dimensions described above from the scope of this disclosure.

[0027] The body 100 may include magnetic powder particles (P) and insulating resin (R). Specifically, the body 100 may be formed by stacking at least one magnetic composite sheet comprising insulating resin (R) and magnetic powder particles (P) dispersed in the insulating resin (R), and then curing the magnetic composite sheet. The body 100 may have structures other than those in which the magnetic powder particles (P) are dispersed in the insulating resin (R). For example, the body 100 may be made using a magnetic material such as ferrite.

[0028] The magnetic powder particles (P) can be, for example, ferrite powder particles or magnetic metal powder particles.

[0029] Examples of ferrite powder particles may include at least one of spinel-type ferrites (such as Mg-Zn-based ferrites, Mn-Zn-based ferrites, Mn-Mg-based ferrites, Cu-Zn-based ferrites, Mg-Mn-Sr-based ferrites, Ni-Zn-based ferrites, etc.), hexagonal ferrites (such as Ba-Zn-based ferrites, Ba-Mg-based ferrites, Ba-Ni-based ferrites, Ba-Co-based ferrites, Ba-Ni-Co-based ferrites, etc.), garnet-type ferrites (such as Y-based ferrites, etc.) and Li-based ferrites.

[0030] Magnetic metal powder 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), and nickel (Ni). For example, magnetic metal powder particles may be at least one selected from pure iron powder, Fe-Si based alloy powder, Fe-Si-Al based alloy powder, Fe-Ni based alloy powder, Fe-Ni-Mo based alloy powder, Fe-Ni-Mo-Cu based alloy powder, Fe-Co based alloy powder, Fe-Ni-Co based alloy powder, Fe-Cr based alloy powder, Fe-Cr-Si based alloy powder, Fe-Si-Cu-Nb based alloy powder, Fe-Ni-Cr based alloy powder, and Fe-Cr-Al based alloy powder.

[0031] Magnetic metal powder particles can be amorphous or crystalline. For example, magnetic metal powder particles can be Fe-Si-B-Cr based amorphous alloy powder particles, but are not limited to this.

[0032] Ferrite powder particles and magnetic metal powder particles may have an average diameter of approximately 0.1 μm to 30 μm, but are not limited thereto.

[0033] Body 100 may include two or more types of magnetic powder particles (P) dispersed in an insulating resin (R). In this context, the term "different types of magnetic powder particles (P)" means that the magnetic powder particles (P) dispersed in the insulating resin (R) are distinguished from each other by diameter, composition, crystallinity, and shape. For example, body 100 may include two or more magnetic powder particles (P) of different diameters.

[0034] The insulating resin (R) may include, but is not limited to, epoxy resins, polyimides, liquid crystal polymers, etc., either alone or in combination.

[0035] The main body 100 may include a core (C) extending through the coil portion 300, which will be described later. The core (C) may be formed by filling a through-hole formed in the insulating substrate 200 with at least a portion of the magnetic composite sheet during the stacking and curing of the magnetic composite sheet, but is not limited thereto.

[0036] The main body 100 may have an effective portion 110 and covering portions 120 and 130 disposed on the effective portion 110. The effective portion 110 may refer to the area in the main body 100 where the coil portion 300 is disposed, and the covering portions 120 and 130 may refer to the areas disposed on the effective portion 110 of the main body 100. As a non-limiting example, based on... Figure 2 and Figure 3The effective portion 110 may refer to an area of ​​the main body 100 corresponding to the distance from the lower surface of the first coil pattern 311 to the upper surface of the second coil pattern 312, and the covering portions 120 and 130 may refer to other areas of the main body 100 respectively disposed on the first coil pattern 311 and the second coil pattern 312. Based on Figure 2 and Figure 3 The covering portions 120 and 130 may include an upper covering portion 120, which may be the upper region of the main body 100, and a lower covering portion 130, which may be the lower region of the main body 100.

[0037] The thickness (T2) of the upper cover 120 can be formed in the range of greater than 90 μm to less than 120 μm. For example, the thickness (T2) of the upper cover 120 satisfies 90 μm < T2 < 120 μm. When the thickness (T2) of the upper cover 120 is 90 μm or less, it may be difficult to ensure a large capacitance inductance, and when the thickness (T2) of the upper cover 120 is 120 μm or greater, it may be detrimental to making the coil assembly thinner. The above description of the thickness (T2) of the upper cover 120 can also be applied to the lower cover 130.

[0038] As a non-limiting example, the effective portion 110 may have a higher permeability than the covering portions 120 and 130. Therefore, the magnetic powder particles (P) disposed in the effective portion 110 may have a higher permeability than the magnetic powder particles (P) disposed in the covering portions 120 and 130. Optionally, the filling rate of the magnetic powder particles (P) in the effective portion 110 may be higher than the filling rate of the magnetic powder particles (P) in the covering portions 120 and 130.

[0039] The insulating substrate 200 can be embedded in the main body 100. The insulating substrate 200 can be configured to support the coil portion 300, which will be described later.

[0040] The insulating substrate 200 can be formed using insulating materials including thermosetting insulating resins such as epoxy resins, thermoplastic insulating resins such as polyimide, or photosensitive insulating resins, or using insulating materials with reinforcing materials such as glass fiber or inorganic fillers impregnated in such insulating resins. For example, the insulating substrate 200 can be formed using insulating materials such as prepregs, ABF (Ajinomoto Build-up Film), FR-4, bismaleimide triazine (BT) film, photosensitive dielectric (PID) film, etc., but is not limited thereto.

[0041] At least one of the following can be used as an inorganic filler: silicon dioxide (SiO2), aluminum oxide (Al2O3), silicon carbide (SiC), barium sulfate (BaSO4), talc, mud, 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).

[0042] When the insulating substrate 200 is formed using an insulating material including reinforcing material, the insulating substrate 200 provides better rigidity. When the insulating substrate 200 is formed using an insulating material that does not contain glass fibers, the insulating substrate 200 can help reduce the overall thickness of the coil portion 300. When the insulating substrate 200 is formed using an insulating material containing photosensitive insulating resin, the number of processes used to form the coil portion 300 can be reduced. Therefore, it is beneficial to reduce production costs and to form fine vias.

[0043] The thickness (T1) of the insulating substrate 200 can be formed to be greater than 20 μm but less than 30 μm. For example, it can satisfy 20 μm < T1 ≤ 30 μm. When the thickness (T1) of the insulating substrate 200 is 20 μm or less, it may be difficult to ensure the rigidity of the insulating substrate 200, and it may be difficult to support the coil portion 300, which will be described later, in the manufacturing process. When the thickness (T1) of the insulating substrate 200 is greater than 30 μm, it may be disadvantageous to reduce the width of the coil assembly.

[0044] The ratio of the thickness (T2) of the upper cover 120 to the thickness (T1) of the insulating substrate 200 can be greater than 3 but less than 6. For example, 3 < T2 / T1 < 6 can be satisfied. When the ratio of T2 to T1 is 3 or less, the inductance may decrease. When the ratio of T2 to T1 is 6 or greater, the DC resistance (Rdc) may increase.

[0045] The coil portion 300 can be embedded in the main body 100 to display the characteristics of the coil portion. For example, when the coil assembly 1000 of this embodiment is used as a power inductor, the coil portion 300 can be used to stabilize the power supply of electronic devices by storing the electric field as a magnetic field and maintaining the output voltage.

[0046] The coil portion 300 may include coil patterns 311 and 312 and a via 320. Specifically, based on Figure 1 , Figure 2 and Figure 3In this configuration, the first coil pattern 311 can be disposed on the lower surface of the insulating substrate 200 facing the sixth surface 106 of the main body 100, and the second coil pattern 312 can be disposed on the upper surface of the insulating substrate 200 facing the fifth surface 105 of the main body 100. A via 320 can penetrate the insulating substrate 200 and can respectively contact and connect to the first coil pattern 311 and the second coil pattern 312. In this configuration, the coil portion 300 can be used as a single coil forming one or more turns around the core (C).

[0047] Each of the first coil pattern 311 and the second coil pattern 312 may be in the form of a planar spiral shape having at least one turn around the core (C). For example, the first coil pattern 311 may have at least one turn around the core (C) on the lower surface of the insulating substrate 200.

[0048] At least one of via 320 and coil patterns 311 and 312 may include at least one conductive layer. For example, when the second coil pattern 312 and via 320 are formed on the side of the upper surface of the insulating substrate 200 by a plating process, the second coil pattern 312 and via 320 may each include a seed layer and an electroplated layer. In this case, each of the seed layer and the electroplated layer may have a single-layer structure or a multi-layer structure. The multi-layer electroplated layer may be formed using a conformal film structure in which one electroplated layer is covered by another electroplated layer, or by another electroplated layer being stacked only on one surface of the first electroplated layer. The seed layer may be formed by a vapor deposition process such as an electroless plating process or a sputtering process. In the former case, the seed layer may be formed using an electroless copper plating solution, but is not limited thereto. In the latter case, the seed layer may include at least one of titanium (Ti), chromium (Cr), nickel (Ni), and copper (Cu). The seed layer of the second coil pattern 312 and the seed layer of the via 320 may be formed integrally, and there may be no boundary between them, but is not limited thereto. The electroplated layer of the second coil pattern 312 and the electroplated layer of the via 320 can be formed integrally, and there may be no boundary between them, but it is not limited to this.

[0049] As another example, when a first coil pattern 311 disposed on the lower surface of the insulating substrate 200 and a second coil pattern 312 disposed on the upper surface of the insulating substrate 200 are formed individually and then stacked in batches on the insulating substrate 200 to form a coil portion 300, the via 320 may include a high-melting-point metal layer and a low-melting-point metal layer having a melting point lower than that of the high-melting-point metal layer. In this case, the low-melting-point metal layer may be formed using solder containing lead (Pb) and / or tin (Sn). During batch stacking, the low-melting-point metal layer will at least partially melt due to pressure and temperature. Therefore, an intermetallic compound (IMC) layer, for example, may be formed at a portion of the boundary between the low-melting-point metal layer and the second coil pattern 312.

[0050] based on Figures 1 to 3 In this configuration, coil patterns 311 and 312 can protrude from two surfaces of the insulating substrate 200, respectively. As another example, the first coil pattern 311 can protrude from the lower surface of the insulating substrate 200, and the second coil pattern 312 can be embedded in the upper surface of the insulating substrate 200 to expose its upper surface. In this case, since a recess can be formed in the upper surface of the second coil pattern 312, the upper surface of the second coil pattern 312 and the upper surface of the insulating substrate 200 may not be on the same plane. As another example, the second coil pattern 312 can protrude from the upper surface of the insulating substrate 200, and the first coil pattern 311 can be embedded in the lower surface of the insulating substrate 200 to expose its lower surface. In this case, since a recess can be formed in the lower surface of the first coil pattern 311, the lower surface of the first coil pattern 311 and the lower surface of the insulating substrate 200 may not be on the same plane.

[0051] Each of the vias 320 and coil patterns 311 and 312 may be formed using, but is not limited to, a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or alloys thereof.

[0052] External electrodes 400 and 500 may be disposed on the surface of the main body 100 and may be connected to the two ends of the coil portion 300, respectively. In this embodiment, the two ends of the coil portion 300 may be exposed from the first surface 101 and the second surface 102 of the main body 100, respectively. The first external electrode 400 may be disposed on the first surface 101 and may contact and connect to the end of the first coil pattern 311 exposed from the first surface 101 of the main body 100. The second external electrode 500 may be disposed on the second surface 102 and may contact and connect to the end of the second coil pattern 312 exposed from the second surface 102 of the main body 100.

[0053] External electrodes 400 and 500 may have a single-layer or multi-layer structure. For example, the first external electrode 400 may include a first layer containing copper (Cu), a second layer containing nickel (Ni) disposed on the first layer, and a third layer containing tin (Sn) disposed on the second layer. The first, second, and third layers may be formed by electroplating processes, but are not limited thereto. As another example, the first external electrode 400 may include a resin electrode containing conductive powder particles and resin, and a plating layer formed on the resin electrode by a plating process.

[0054] The external electrodes 400 and 500 may be formed using conductive materials such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or alloys thereof, but are not limited thereto.

[0055] An insulating film 600 may be formed on the insulating substrate 200 and the coil portion 300. The insulating film 600 serves to insulate the coil portion 300 from the body 100, and may include known insulating materials such as parylene. The insulating material included in the insulating film 600 can be any material and is not particularly limited thereto. The insulating film 600 may be formed using processes such as vapor deposition, but is not limited thereto, and may be formed by stacking insulating films on both surfaces of the insulating substrate 200. In the former case, the insulating film 600 may be formed as a conformal film along the surfaces of the insulating substrate 200 and the coil portion 300. The insulating film 600 may be an optional element, and therefore, the insulating film 600 may be omitted when the body 100 ensures sufficient insulation resistance under the operating conditions of the coil assembly 1000 according to this embodiment.

[0056] (Experimental Example)

[0057] Table 1 shows the changes in inductance (L) and DC resistance (Rdc) caused by variations in the thickness (T1) of the insulating substrate and the thickness (T2) of the upper cover in Experimental Examples 1 to 8.

[0058] In all of the following Experimental Examples 1 to 8, the coil portions were manufactured with the same number of turns. Furthermore, the coil portions were manufactured such that each turn of the coil portion had the same linewidth and the same thickness (e.g., 140 μm for each of the first and second coil patterns), and the spacing between adjacent turns of the coil portion was the same. Finally, the inductance (L) and DC resistance (Rdc) were measured at the same operating frequency.

[0059] [Table 1]

[0060]

[0061]

[0062] In Table 1, each ratio of L (reference change) and Rdc (reference change) was calculated based on 0.47 mmH and 35 mΩ as reference values, respectively. In Table 1, the item "whether thinned" indicates whether the overall thickness of the formed component up to the outer electrode exceeds 0.60 mm. Thus, when the thickness of the entire component exceeds 0.60 mm, it is indicated in Table 1 that the component is not thinned (X). In Table 1, compared with Experimental Examples 7 and 8 that satisfy 3 < T2 / T1 < 6, in the case of Experimental Examples 1, 2, and 5 where the ratio of T2 / T1 is 3 or less, the inductance of the coil component decreases. Compared with Experimental Examples 7 and 8 that satisfy 3 < T2 / T1 < 6, in the case of Experimental Examples 3 and 4 where the ratio of T2 / T1 is 6 or more, the inductance of the coil component increases, but the direct current resistance (Rdc) increases and it is not thinned.

[0063] Referring to Table 1, compared with Experimental Examples 7 and 8 that satisfy 90 μm < T2 < 120 μm, in the case of Experimental Example 5 where T2 is 90 μm or less, the inductance (L) decreased by 10% or more. Compared with Experimental Examples 7 and 8 that satisfy 90 μm < T2 < 120 μm, in the case of Experimental Example 6 where T2 is 120 μm or more, it is impossible to reduce the thickness.

[0064] Therefore, as shown in Table 1, in the case of Experimental Examples 7 and 8 that satisfy both 3 < T2 / T1 < 6 and 90 μm < T2 < 120 μm, the inductance (L) of the coil component is ensured while achieving thinning.

[0065] In the case of Experimental Example 7, compared with the reference value, the inductance of the coil component is slightly less than the reference inductance, but within the allowable range of 10%.

[0066] In this configuration, the coil component 1000 according to the present embodiment can achieve a large-capacity inductance and a low direct current resistance (Rdc) while reducing the thickness of the coil component 1000.

[0067] According to the present disclosure, a large-capacity inductance and a low direct current (DC) resistance (Rdc) can be ensured while the coil component can be made into a small profile.

[0068] Although the example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope of the present disclosure defined by the appended claims.

Claims

1. A coil assembly comprising: an insulating substrate; a first coil pattern having a planar spiral shape, provided on one surface of the insulating substrate; a second coil pattern having a planar spiral shape, provided on the other surface of the insulating substrate opposite to the one surface of the insulating substrate; and a main body in which the insulating substrate, the first coil pattern, and the second coil pattern are embedded, and the main body has an effective portion in which the first coil pattern and the second coil pattern are provided, an upper cover portion provided on an upper surface of the effective portion, and a lower cover portion provided on a lower surface of the effective portion; and wherein a thickness of the main body is 550 μm or less, and wherein a ratio of a thickness T2 of the upper cover portion to a thickness Tl of the insulating substrate satisfies 3 < T2 / Tl < 4.

2. The coil assembly of claim 1, wherein, The thickness Tl of the insulating substrate satisfies 20 μm < Tl ≤ 30 μm.

3. The coil assembly according to claim 1, further comprising: a via hole penetrating through the insulating substrate to connect the first coil pattern and the second coil pattern to each other.

4. The coil assembly of claim 1, wherein, The main body includes an insulating resin and magnetic powder particles.

5. The coil assembly according to claim 1, further comprising first and second outer electrodes provided on a surface of the main body to be connected to end portions of the first and second coil patterns, respectively.

6. The coil assembly of claim 5, wherein, A thickness of the coil assembly is 600 μm or less.

7. The coil assembly according to claim 1, further comprising an insulating film provided to cover and be in contact with the first and second coil patterns.

8. The coil assembly of claim 7, wherein, The insulating substrate includes a through hole that provides an inner side surface of the insulating substrate, and The insulating film further covers an outer side surface and the inner side surface of the insulating substrate.

9. The coil assembly of claim 1, wherein, The ratio of the thickness T2 of the upper cover portion to the thickness Tl of the insulating substrate satisfies 3 < T2 / Tl ≤ 3.

83.

10. The coil assembly of claim 1, wherein, The thickness T2 of the upper cover portion satisfies 90 μm < T2 < 120 μm.

11. The coil assembly of claim 1, wherein, The thickness T2 of the upper cover portion satisfies 105 μm ≤ T2 ≤ 115 μm, and the ratio of the thickness T2 of the upper cover portion to the thickness Tl of the insulating substrate satisfies 3.5 ≤ T2 / Tl ≤ 3.83.

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