Coil assembly

Abstract

A coil assembly is provided. The coil assembly includes a main body including a magnetic material, a support member disposed in the main body, and a coil disposed on the support member. One surface of the support member has a roughness, and a side surface of the coil has a roughness. A maximum height roughness Rmax_s of the one surface of the support member is greater than a maximum height roughness Rmax_c of the side surface of the coil, thereby improving adhesion between the coil and the support member while achieving fine patterning of the coil.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0193242, filed on December 20, 2024, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates to a coil assembly. Background Technology

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

[0004] With the advancement of information technology (IT), the reduction in size (e.g., thickness) of various electronic devices has been accelerating. Therefore, thin-film inductors used in such electronic devices have also been required to have reduced size (e.g., thickness).

[0005] Because power inductors have a reduced thickness, research and development have been conducted on increasing the number of turns (fine patterning) and increasing the height of the coil pattern in order to reduce the size of the product without sacrificing chip characteristics (such as inductance and DC resistance (Rdc)).

[0006] As the coil pattern becomes more refined, the adhesion between the coil pattern and the substrate may decrease, which could cause coil lifting defects. Summary of the Invention

[0007] One aspect of this disclosure is to provide a coil assembly that enables fine patterning of coil patterns while ensuring adhesion to a support member.

[0008] According to one aspect of this disclosure, a coil assembly is provided, the coil assembly comprising: a body comprising a magnetic material; a support member disposed in the body, the support member having a roughness formed on one surface of the support member; and a coil disposed on said one surface of the support member, the coil having a roughness formed on a side surface of the coil. The maximum height roughness Rmax_s of the one surface of the support member on which the roughness is formed may be greater than the maximum height roughness Rmax_c of the side surface of the coil on which the roughness is formed.

[0009] According to another aspect of this disclosure, a coil assembly is provided, the coil assembly comprising: a body comprising a magnetic material; a support member disposed in the body, the support member having a roughness formed on one surface of the support member; and a coil disposed on said one surface of the support member, the coil having a roughness formed on a side surface of the coil. The maximum height roughness Rmax_c of the side surface on which the roughness is formed of the coil may have a value greater than or equal to 10 nm and less than or equal to 100 nm.

[0010] According to this disclosure, the coil assembly can achieve fine patterning of the coil pattern while ensuring adhesion to the support member. Attached Figure Description

[0011] The above and other aspects, features and advantages of this disclosure will become clearer from the following detailed embodiments, taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of a coil assembly according to an exemplary embodiment of the present disclosure; Figure 2 It is along Figure 1 A cross-sectional view taken from line I-I'; Figure 3 It is along Figure 1 A cross-sectional view taken from line II-II'; Figure 4 yes Figure 2 An enlarged view of part A; and Figures 5A to 5G The manufacturing process of the coil assembly according to this disclosure is shown. Detailed Implementation

[0012] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any one or any combination of any two or more of the associated listed items. It will be further understood that when the terms "comprising" and / or "including" are used in this disclosure, the presence of the stated features, quantities, steps, operations, elements, components, and / or combinations thereof is enumerated, but the presence or addition of one or more other features, quantities, steps, operations, elements, components, and / or combinations thereof is not excluded. Additionally, the terms "set on," "located on," etc., may mean that an element is located on or below a target portion and do not necessarily mean that the element is located on the upper side of the target portion relative to the direction of gravity.

[0013] The terms “integrated into” and “connected to” can refer not only to elements that are in direct physical contact with each other, but also to a structure in which another element is located between the elements so that the element is also in contact with the other element.

[0014] The dimensions (e.g., thickness) of each element shown in the accompanying drawings are arbitrarily depicted for ease of description, but this disclosure is not limited to the dimensions (e.g., thickness) shown herein.

[0015] In the accompanying drawings, the X direction can be defined as a first direction or a length direction, the Y direction can be defined as a second direction or a width direction, and the Z direction can be defined as a third direction or a thickness direction.

[0016] In the following description, a coil assembly according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In the description with reference to the drawings, the same or corresponding elements are indicated by the same reference numerals, and repeated descriptions thereof will be omitted.

[0017] Various types of electronic components can be used in electronic devices, and various types of coil components can be appropriately used among such electronic components to remove noise.

[0018] In other words, in electronic devices, coil assemblies can be used as power inductors, high-frequency inductors, ordinary ferrite beads, high-frequency ferrite beads (e.g., ferrite beads suitable for the GHz band), common-mode filters, etc.

[0019] Figure 1 This is a schematic diagram of a coil assembly according to an exemplary 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'. Figure 4 yes Figure 2 An enlarged view of part A.

[0020] Reference Figures 1 to 4 According to an example embodiment of the present disclosure, the coil assembly 1000 may include a body 100, a support member 200 and a coil 300, and may also include an insulating film IF and external electrodes 500 and 600.

[0021] The body 100 may form the overall appearance of the coil assembly 1000 according to this example embodiment, and may include a support member 200 and a coil 300 embedded in the body 100.

[0022] The main body 100 can have a hexahedral shape as a whole.

[0023] Reference Figures 1 to 3The body 100 may include a first surface 101 and a second surface 102 that are opposite each other in the length direction (X direction), a third surface 103 and a fourth surface 104 that are opposite each other in the width direction (Y direction), and a fifth surface 105 and a sixth surface 106 that are opposite each other in the thickness direction (Z direction). Each of the first surface 101, the second surface 102, the third surface 103, and the fourth surface 104 of the body 100 may correspond to a side surface of the body 100 that connects the fifth surface 105 and the sixth surface 106 to each other.

[0024] The body 100 may be configured such that the coil assembly 1000, in which the external electrodes 500 and 600, described below, are formed according to this exemplary embodiment, may have a length of 0.8 mm, a width of 0.65 mm, and a thickness of 0.45 mm, but this disclosure is not limited thereto. The above dimensions of the coil assembly 1000 are merely exemplary, and cases in which the coil assembly 1000 has dimensions other than those described above are not excluded from the scope of this disclosure.

[0025] The body 100 may include a magnetic material and a resin. Specifically, the body 100 may be formed by laminating one or more magnetic composite sheets comprising a resin and magnetic particles dispersed in the resin, and then curing the magnetic composite sheets. However, the body 100 may have a structure other than that in which the magnetic particles are dispersed in the resin. For example, the body 100 may be formed using a magnetic material such as ferrite.

[0026] Magnetic materials can be, for example, ferrite particles or magnetic metal particles.

[0027] The ferrite particles can be, for example, spinel-type ferrite particles (such as Mg-Zn-based ferrite particles, Mn-Zn-based ferrite particles, Mn-Mg-based ferrite particles, Cu-Zn-based ferrite particles, Mg-Mn-Sr-based ferrite particles, Ni-Zn-based ferrite particles, etc.), hexagonal ferrite particles (such as Ba-Zn-based ferrite particles, Ba-Mg-based ferrite particles, Ba-Ni-based ferrite particles, Ba-Co-based ferrite particles, Ba-Ni-Co-based ferrite particles, etc.), garnet-type ferrite particles (such as yttrium (Y)-based ferrite particles, etc.), and Li-based ferrite particles.

[0028] 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), and nickel (Ni). For example, magnetic metal particles may be at least one selected from pure iron particles, Fe-Si based alloy particles, Fe-Si-Al based alloy particles, Fe-Ni based alloy particles, Fe-Ni-Mo based alloy particles, Fe-Ni-Mo-Cu based alloy particles, Fe-Co based alloy particles, Fe-Ni-Co based alloy particles, Fe-Cr based alloy particles, Fe-Cr-Si based alloy particles, Fe-Si-Cu-Nb based alloy particles, Fe-Ni-Cr based alloy particles, and Fe-Cr-Al based alloy particles.

[0029] The magnetic metal particles can be amorphous or crystalline. For example, the magnetic metal particles can be Fe-Si-B-Cr based amorphous alloy particles, but this disclosure is not limited thereto.

[0030] Each of the ferrite particles and magnetic metal particles may have an average diameter of about 0.1 μm to about 30 μm, but this disclosure is not limited thereto.

[0031] The body 100 may include two or more different types of magnetic particles dispersed in a resin. Here, different types of magnetic particles may mean that the magnetic particles differ from each other in at least one aspect of average diameter, composition, crystallinity, and shape. For example, the body 100 may include two or more types of magnetic particles with different particle sizes.

[0032] The resin may include, alone or in combination, epoxy resin, polyimide, liquid crystal polymer, etc., but this disclosure is not limited thereto.

[0033] The body 100 may include a core 110 passing through the support member 200 and the coil 300, which will be described below. During the process of laminating and curing the magnetic composite sheet, the core 110 may be formed by filling the through-holes of the coil 300 with at least a portion of the magnetic composite sheet, but this disclosure is not limited thereto.

[0034] The support member 200 may have one surface and another surface, and may be embedded in the body 100 together with the coil 300, which will be described below. The support member 200 may be configured to support the coil 300. In this example embodiment, one surface of the support member 200 is described for ease of description, but this disclosure is not limited thereto. The description of one surface of the support member 200 may also be applied to the other surface of the support member 200.

[0035] The support member 200 may 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, or the support member 200 may be formed using an insulating material prepared by impregnating a reinforcing material (such as glass fiber or inorganic filler) in the aforementioned insulating resin. For example, the support member 200 may be formed using insulating materials such as copper clad laminate (CCL), prepreg, Ajinomoto laminate (ABF), FR-4, bismaleimide triazine (BT) film, photosensitive dielectric (PID) film, etc., but this disclosure is not limited thereto.

[0036] 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, 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).

[0037] When the support member 200 is formed using an insulating material including reinforcing material, the support member 200 can provide superior rigidity. When the support member 200 is formed using an insulating material that does not include glass fiber, the support member 200 can help reduce the overall thickness of the coil 300. When the support member 200 is formed using an insulating material including a photosensitive insulating resin, the number of processes used to form the coil 300 can be reduced, which can help reduce production costs and allows for the formation of fine vias.

[0038] Reference Figures 2 to 4 The support member 200 may have a roughness 210G formed on one of its surfaces. The maximum height roughness Rmax_s of the surface of the support member 200 on which the roughness 210G is formed may be greater than or equal to 1 μm and less than or equal to 7.5 μm. As the coil pattern becomes finer, the adhesion between the coil pattern and the substrate (e.g., the support member) may decrease, and defects such as coil warping may occur. Therefore, in the coil assembly according to this example embodiment, by forming a roughness with a maximum height roughness Rmax_s greater than or equal to 1 μm and less than or equal to 7.5 μm on the support member 200, the adhesion between the coil and the support member can be ensured.

[0039] When the maximum height roughness Rmax_s is less than 1 μm, the adhesion between the support member 200 and the coil 300 may decrease. When the maximum height roughness Rmax_s is greater than 7.5 μm, the rigidity of the support member 200 may decrease, which may be detrimental to the formation of a coil 300 with a large aspect ratio.

[0040] The roughness 210G of the support member 200 of the coil assembly 1000 according to this example embodiment can be formed by performing plasma treatment on the support member 200. Specifically, in a state where the coil 300 has not yet been formed, surface etching can be performed on one surface of the support member 200 using plasma, and roughness 210G can be formed on one surface of the support member 200.

[0041] As will be described below, a roughness 310G can be formed on the side surface of the coil 300, and the maximum height roughness Rmax_s of a surface of the support member 200 on which the roughness 210G is formed can be greater than the maximum height roughness Rmax_c of the side surface of the coil 300 on which the roughness 310G is formed.

[0042] The thickness of the support member 200 can be greater than or equal to 10 μm and less than or equal to 20 μm. When the thickness of the support member 200 is less than 10 μm, it may be difficult to ensure the rigidity of the support member 200, and therefore it may be difficult to support the coil 300, which will be described below, during the manufacturing process. When the thickness of the support member 200 is greater than 20 μm, it may be disadvantageous to reducing the thickness of the coil assembly, and the volume occupied by the support member 200 may increase within the same volume of the main body, which may be detrimental to achieving high inductance.

[0043] The coil 300 may be disposed on one surface of the support member 200 and may be formed in multiple turns to exhibit the characteristics of the coil assembly 1000. For example, when the coil assembly 1000 according to this example embodiment is used as a power inductor, the coil 300 may be used to maintain the output voltage by storing the electric field as a magnetic field, thereby stabilizing the power of the electronic device.

[0044] The coil 300 may include a first coil pattern 310 disposed on one surface of the support member 200 and a second coil pattern 320 disposed on another surface of the support member 200. The following description will be based on the first coil pattern 310.

[0045] Reference Figure 4 The first coil pattern 310 can be disposed on a surface of the support member 200 having a roughness 210G. Due to the roughness 210G on the surface of the support member 200, the adhesion between the first coil pattern 310 and the support member 200 can be ensured.

[0046] Reference Figure 4A roughness 310G can be formed on the side surface of the first coil pattern 310. The maximum height roughness Rmax_c of the side surface of the coil 300 on which the roughness 310G is formed can have a value greater than or equal to 10 nm and less than or equal to 100 nm. As will be described below, the plating layer 312 can be formed by using the opening of the insulating wall as a plating growth guide. The partition pattern of the insulating wall can be etched, thereby forming a roughness on the side surface of the insulating wall. The roughness of the side surface of the insulating wall can be transferred to the side surface of the first coil pattern 310, so that the roughness 310G can be formed on the side surface of the first coil pattern 310.

[0047] The upper surface of the first coil pattern 310 may not have a roughness. The upper surface of the first coil pattern 310 may not contact the side surface of the insulating wall 420, so that the roughness may not be transferred. Therefore, the maximum height roughness of the upper surface of the first coil pattern 310 may be less than 10 nm.

[0048] When a roughness of 310G is formed on the side surface of the coil 300, the adhesion between the coil 300 and the insulating film IF can be improved. Specifically, the insulating film IF for insulating the body 100 can be disposed on the surface of the coil 300, and the insulating film IF can include commonly used insulating materials (such as parylene), but embodiments thereof are not limited thereto. The insulating film IF can be formed by methods such as vapor deposition, but embodiments thereof are not limited thereto, and the insulating film IF can be formed by laminating insulating films. Table 1 below shows the results of measuring the adhesion between the coil 300 and the insulating film IF according to the variation of the maximum height roughness Rmax_c of the side surface of the coil 300. Referring to Table 1, when the maximum height roughness Rmax_c of the side surface of the coil 300 is greater than or equal to 10 nm, the adhesion between the coil 300 and the insulating film IF can be increased, and stable insulation performance can be ensured (i.e., the adhesion is improved).

[0049] [Table 1]

[0050] In Table 1, OK indicates that the adhesion has been improved; NG indicates that the adhesion has not been improved.

[0051] When the side surface of coil 300 has an excessively large maximum height roughness Rmax_c, the resistance may increase due to the increased surface area of ​​coil 300, which may degrade component characteristics. Table 2 below shows the results of measuring coil resistance based on the variation of the maximum height roughness Rmax_c of the side surface of coil 300. In Table 2, if the resistance change rate is less than or equal to 10%, it is considered to meet the Rdc specification and marked as OK; if the resistance change rate exceeds 10%, it is considered to not meet the Rdc specification and marked as NG. Referring to Table 2, when the maximum height roughness Rmax_c of the side surface of coil 300 is greater than 100 nm, the resistance can increase by more than 10% compared to the comparative example where no roughness is formed (e.g., the resistance change rate can exceed 10%), thus reducing component characteristics (Rdc).

[0052] [Table 2]

[0053] The distance between adjacent turns in the multiple turns of coil 300 can be greater than or equal to 3 μm and less than or equal to 10 μm. As will be described below, plating 312 can be formed by using openings in the insulating wall as plating growth guides, and the distance between adjacent turns in the multiple turns of coil 300 can be adjusted by reducing the width of the insulating wall.

[0054] When the partition wall method is used to form the plating 312, the coil assembly 1000 according to this example embodiment can undergo plasma treatment to reduce the size of the partition wall. In the partition wall method according to the prior art, the width of the partition wall can have a minimum value of 10 μm, and there are limitations in reducing the width of the partition wall to a value less than or equal to the above value. However, in this example embodiment, the partition wall pattern can be etched using a plasma method, which can reduce the width of the partition wall, and therefore, the distance between adjacent turns of the coil 300 can be reduced. Even when the size of the partition wall is reduced, the adhesion between the partition wall to which it has undergone plasma treatment and the support member 200 can be increased, thereby stabilizing the formation of the coil 300. In addition, residues of partition wall material may remain in the coil formation area ( Figure 5D In the 420h shown, however, unwanted residues on the support member 200 can be removed by plasma treatment, thereby stabilizing the formation of the coil 300. As will be described below, the insulating wall 420 may include a resist, but the interface between the support member 200 and the coil 300 may not contain resist residues.

[0055] As described above, the maximum height roughness Rmax_s of the support member 200 having a roughness of 210G can be greater than the maximum height roughness Rmax_c of the side surface of the coil 300 having a roughness of 310G.

[0056] The maximum height and maximum height roughness of the side surface of the support member 200 or the coil 300 of the coil assembly 1000 according to this example embodiment can be measured using the following methods.

[0057] The maximum height roughness Rmax_s of roughness 210G can be measured by preparing an XZ section sample passing through the center of the body 100, and then observing the prepared sample using a scanning electron microscope (SEM). The maximum height is obtained by measuring the maximum peak-to-valley value of the cross-sectional roughness profile in the sampled portion. Specifically, the maximum height roughness Rmax_s can be obtained by measuring the vertical distance between two parallel lines passing through the highest and lowest points of the roughness curve within a reference length of the sampled portion.

[0058] The maximum height roughness Rmax_c of roughness 310G can be measured by preparing an XZ section sample passing through the center of the body 100, flattening the sample, and then observing the prepared sample using an atomic force microscope (AFM). The maximum height roughness Rmax_c of roughness 310G at the side surface of coil 300 can be determined as the vertical distance between two parallel lines passing through the highest and lowest points of the roughness curve within the reference length of the sampling portion.

[0059] Maximum height roughness can also be measured using an optical surface profilometer or surface roughness tester, and maximum height roughness can refer to the arithmetic mean of multiple measurements.

[0060] The first coil pattern 310 may include a seed layer 311 disposed on the support member 200 and a plating layer 312 disposed on the seed layer 311. That is, the coil 300 in this example embodiment may be a thin-film coil formed using a plating method.

[0061] The seed layer 311 can be formed using thin film processes (such as sputtering) or electroless plating processes. The seed layer 311 may include at least one of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), chromium (Cr), molybdenum (Mo), and alloys thereof, and may be formed as at least one layer.

[0062] The plating layer 312 can be formed by performing an electrolytic plating process using a seed layer 311 as a seed, and the plating layer 312 may include at least one of copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), platinum (Pt), titanium (Ti), chromium (Cr) and alloys thereof, and may be formed as at least one layer.

[0063] The coil 300 may include a first coil pattern 310, a second coil pattern 320, and a via 330. Figure 1 , Figure 2 and Figure 3 In the direction of the first coil pattern 310, the first coil pattern 310 may be disposed on one surface of the support member 200 opposite to the sixth surface 106 of the main body 100, and the second coil pattern 320 may be disposed on another surface of the support member 200 opposite to the first surface.

[0064] Reference Figures 1 to 3 The via 330 can pass through the support member 200 to contact each of the first coil pattern 310 disposed on one surface of the support member 200 and the second coil pattern 320 disposed on the other surface of the support member 200 to connect the first coil pattern 310 and the second coil pattern 320 to each other. Thus, the coil 300 can be used as a single coil in which one or more turns are formed around the core 110.

[0065] Via 330 may include at least one plating layer. For example, when via 330 is formed by an electroplating process, via 330 may include a seed layer formed on the inner wall of the via hole passing through the support member 200 and an electroplated layer filling the via hole in which the seed layer is formed. The seed layer of via 330 and the seed layer for forming coil 300 may be formed together in the same process to be integrally formed with each other, or they may be formed in different processes such that a boundary can be formed between them. Via 330 may include a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), chromium (Cr), molybdenum (Mo), or alloys thereof.

[0066] The end of coil 300 can be connected to the first external electrode 500 and the second external electrode 600, which will be described below. (Refer to...) Figure 1 and Figure 2 The end of the first coil pattern 310 may be exposed on the first surface 101 of the body 100 and connected to the first external electrode 500, and the end of the second coil pattern 320 may be exposed on the second surface 102 of the body 100 and connected to the second external electrode 600.

[0067] The first external electrode 500 and the second external electrode 600 may be disposed on the first surface 101 and the second surface 102 of the main body 100, respectively. The first external electrode 500 may be disposed on the first surface 101 of the main body 100 and connected to the end of the first coil pattern 310. The second external electrode 600 may be disposed on the second surface 102 of the main body 100 and connected to the end of the second coil pattern 320.

[0068] The first external electrode 500 and the second external electrode 600 may have a single-layer structure or a multi-layer structure. For example, the first external electrode 500 may include: a first layer comprising copper (Cu); a second layer disposed on the first layer, the second layer comprising nickel (Ni); and a third layer disposed on the second layer, the third layer comprising tin (Sn). Here, the first, second, and third layers may be formed by plating, but this disclosure is not limited thereto. As another example, the first external electrode 500 may include a resin electrode comprising conductive particles (such as silver (Ag)) and resin, and a nickel (Ni) plating / tin (Sn) plating formed on the resin electrode.

[0069] The first external electrode 500 and the second external electrode 600 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 this disclosure is not limited thereto.

[0070] The insulating film IF insulates the coil 300 from the body 100. The insulating film IF can cover the outer surface of the coil 300, thereby insulating the coil 300 from the body 100.

[0071] The insulating film IF can be formed along the outer surface of the coil 300 in the form of a conformal film. The insulating film IF can cover the upper surface of the coil 300 and can be disposed between multiple turns of the coil 300.

[0072] The insulating film IF may include known insulating materials (such as parylene, etc.), but this disclosure is not limited thereto. As another example, the insulating film IF may include insulating materials (such as epoxy resin, etc., instead of parylene). The insulating film IF may be formed using a vapor deposition method, but this disclosure is not limited thereto. As another example, the insulating film IF may be formed by laminating and curing an insulating film for forming the insulating film IF onto the two surfaces of the support member 200 on which the coil 300 is formed, and the insulating film IF may be formed by coating and curing an insulating paste for forming the insulating film IF onto the two surfaces of the support member 200 on which the coil 300 is formed.

[0073] In this disclosure, the insulating film IF may be an optional element. The insulating film IF may be omitted when the body 100 can ensure sufficient resistance under the operating conditions of the coil assembly 1000 according to this example embodiment.

[0074] The following section describes an example method for manufacturing a coil assembly having the above structure. Figures 5A to 5G This is a diagram illustrating the sequential process used to form the coil assembly.

[0075] Reference Figure 5AFirst, a support member 200 can be fabricated, and a roughness 210G can be formed by performing plasma etching on one and another surface of the support member 200. As described above, the maximum height roughness Rmax_s of the roughness 210G formed on one surface of the support member 200 can be greater than or equal to 1 μm and less than or equal to 7.5 μm. The roughness 210G can be formed on the support member 200, thereby ensuring sufficient adhesion between the support member 200 and the coil. The support member 200 can be obtained by removing copper foil from a CCL or similar material according to the prior art, but this disclosure is not limited thereto.

[0076] Reference Figure 5B A seed layer 311 can be formed on a support member 200 having a roughness of 210G. The seed layer 311 can be formed using a dry film using known methods (e.g., chemical vapor deposition (CVD), physical vapor deposition (PVD), sputtering, etc.), but this disclosure is not limited thereto.

[0077] Reference Figure 5C An insulating wall 420 may be formed on each of the two surfaces of the support member 200 on which the seed layer 311 is formed. The insulating wall 420 may be a resist film and may be formed by laminating and curing the resist film, or by coating a material for forming the resist film and curing it, but this disclosure is not limited thereto. For example, the lamination method may include performing hot pressing to press the resist film at a high temperature for a predetermined time period, cooling the resist film to room temperature under reduced pressure, and subsequently performing cold pressing to cool the resist film and separate the working tool from the resist film. The coating method may include, for example, screen printing using a doctor blade to apply ink and spray printing in which the ink is applied in an atomized state. For subsequent photolithography, an incomplete curing drying process may be performed. The insulating wall 420 may include a photosensitive dielectric (PID) that can be stripped by a stripping solution. For example, the insulating wall 420 may include a photosensitive material comprising cyclic ketone compounds and ether compounds having hydroxyl groups as main components. In this case, the cyclic ketone compound can be cyclopentanone, etc., and the ether compound having a hydroxyl group can be polypropylene glycol monomethyl ether, etc. Optionally, the insulating wall 420 may include a photosensitive material comprising a bisphenol-based epoxy resin as a main component. In this case, the bisphenol-based epoxy resin can be bisphenol A phenolic epoxy resin, bisphenol A diglycidyl ether, bisphenol A polymer resin, etc. However, this disclosure is not limited thereto.

[0078] Reference Figure 5D An opening 420h with a planar coil shape can be formed in the insulating wall 420. The opening 420h can be formed using known photolithography methods (i.e., known exposure and development methods). The openings can be patterned sequentially or all at once. There are no limitations on the exposure equipment and developing solution, and they can be appropriately selected according to the photosensitive material used.

[0079] Reference Figure 5E Plasma dry etching can be performed on the insulating wall 420 having the opening 420h. Through plasma treatment, roughness can be formed on the side surface defining the opening 420h of the insulating wall 420. In the prior art partition wall method, the width of the partition wall of the insulating wall 420 can have a minimum value of 10 μm, and there are limitations in reducing the width of the partition wall to a value less than or equal to the above value. However, in this example embodiment, the partition wall pattern can be etched using a plasma method, which can reduce the width of the partition wall, and thus reduce the distance between adjacent turns of the coil 300. Even when the size of the partition wall is reduced, the adhesion between the plasma-treated partition wall and the support member 200 can be increased, thereby enabling stable formation of the coil 300. Additionally, residues of partition wall material may remain in the coil formation area ( Figure 5D In the 420h shown, however, unwanted residues on the support member 200 can be removed by plasma treatment, thereby stabilizing the formation of the coil.

[0080] Reference Figure 5F An opening 420h in the insulating wall 420 can be used as a plating growth guide to form a plating layer 312 on the seed layer 311. In this case, since a roughness is formed on the side surface of the insulating wall 420, a roughness 310G can be formed on the side surface of the coil 300. As described above, the maximum height roughness Rmax_c of the side surface of the coil 300 on which the roughness 310G is formed can have a value greater than or equal to 10 nm and less than or equal to 100 nm. The plating method is not limited and may include electroplating, electroless plating, etc., but this disclosure is not limited thereto.

[0081] Reference Figure 5G After the coil 300 is formed, the insulating wall 420 can be removed. The insulating wall 420 can be removed using a known stripping solution or the like. After removing the insulating wall 420, the seed layer 311 can be etched to form a coil pattern, and the insulating film IF can be selectively formed.

[0082] While exemplary embodiments have been shown and described above, it will be readily understood by those skilled in the art that modifications and variations may be made without departing from the scope of this disclosure as defined by the appended claims.

Claims

1. A coil assembly, comprising: The main body includes magnetic materials; A support member is disposed in the main body, the support member having a roughness formed on one surface of the support member; as well as A coil is disposed on one surface of the support member, the coil having a roughness formed on the side surface of the coil. Wherein, the maximum height roughness of one surface of the support member is greater than the maximum height roughness of the side surface of the coil.

2. The coil assembly according to claim 1, wherein, The maximum height roughness of one surface of the support member has a value greater than or equal to 1 μm and less than or equal to 7.5 μm.

3. The coil assembly according to claim 1, wherein, The maximum height roughness of the side surface of the coil has a value greater than or equal to 10 nm and less than or equal to 100 nm.

4. The coil assembly according to claim 1, wherein, The coil includes a seed layer disposed on one surface of the support member and a plating layer disposed on the seed layer.

5. The coil assembly according to claim 1, wherein, The maximum height roughness of the side surface of the coil has a value greater than or equal to 10 nm and less than or equal to 100 nm, and The maximum height roughness of the upper surface of the coil has a value of less than 10 nm.

6. The coil assembly according to claim 1, wherein, The coil comprises multiple turns.

7. The coil assembly according to claim 6, wherein, The distance between adjacent turns in the multi-turn configuration is greater than or equal to 3 μm and less than or equal to 10 μm.

8. The coil assembly of claim 6, further comprising: An insulating film is disposed between the multiple turns.

9. The coil assembly according to claim 1, wherein, The support member includes another surface opposite to the first surface, and The other surface of the support member is formed with roughness.

10. The coil assembly according to claim 9, wherein, The coil includes: a first coil pattern disposed on one surface of the support member; a second coil pattern disposed on the other surface of the support member; and a through hole passing through the support member, the through hole connecting the first coil pattern and the second coil pattern to each other.

11. The coil assembly according to claim 1, wherein, The interface between the support member and the coil is free of resist residue.

12. A coil assembly, comprising: The main body includes magnetic materials; A support member is disposed in the main body, the support member having a roughness formed on one surface of the support member; as well as A coil is disposed on one surface of the support member, the coil having a roughness formed on the side surface of the coil. The maximum height roughness of the side surface of the coil has a value greater than or equal to 10 nm and less than or equal to 100 nm.

13. The coil assembly according to claim 12, wherein, The maximum height roughness of one surface of the support member has a value greater than or equal to 1 μm and less than or equal to 7.5 μm.

14. The coil assembly of claim 12, wherein, The coil comprises multiple turns, and The distance between adjacent turns in the multi-turn configuration is greater than or equal to 3 μm and less than or equal to 10 μm.

15. The coil assembly according to claim 12, wherein, The support member includes another surface opposite to the first surface, and The other surface of the support member is formed with roughness.

16. The coil assembly of claim 15, wherein, The coil includes: a first coil pattern disposed on one surface of the support member; a second coil pattern disposed on the other surface of the support member; and a through hole passing through the support member, the through hole connecting the first coil pattern and the second coil pattern to each other.

17. The coil assembly of claim 12, wherein, The interface between the support member and the coil is free of resist residue.

Images