Power inductor and manufacturing method thereof

Abstract

The invention discloses a power inductor and a manufacturing method thereof. The power inductor comprises a body; a coil pattern disposed in the body; an external electrode disposed on at least one surface of the body and extending to at least another surface of the body adjacent to the at least one surface; and a coupling layer disposed between the body and the extension region of the external electrode.

Description

[0001] This invention is a divisional application of the patent application with the application number 201880079892.5 and the invention title "Power Inductor and Method of Manufacturing the Same" filed on December 7, 2018. Technical Field

[0002] The present disclosure relates to a power inductor and a method of manufacturing the same, and more particularly to a power inductor and a method of manufacturing the same that can improve the coupling force between the body and the external electrodes. Background Art

[0003] As a chip component, a power inductor is generally disposed on a power supply circuit (e.g., a direct current (DC)-DC converter) in a portable device. Due to the trend of the power supply circuit towards high frequency and miniaturization, power inductors are increasingly used to replace conventional wound-type choke coils. In addition, with the need for small and multifunctional portable devices, development of power inductors is underway to achieve miniaturization, high current, and low resistance.

[0004] A typical power inductor is manufactured in the form of a stacked body in which ceramic sheets formed of various ferrite or dielectric materials with a low dielectric constant are stacked. Here, when coil patterns are formed on each of the ceramic sheets, the coil patterns formed on the ceramic sheets can be connected through vias defined in each of the ceramic sheets, and can have a structure in which the coil patterns overlap each other in the vertical direction in which the sheets are stacked. Generally, the body formed by stacking the ceramic sheets is manufactured using a magnetic material (a quaternary system including nickel (Ni)-zinc (Zn)-copper (Cu)-iron (Fe)).

[0005] However, since the magnetic material has a saturation magnetization value smaller than that of a metal material, it may not be possible to achieve the high current characteristics required for recent portable devices. Therefore, when the body of the power inductor is made of metal powder, the saturation magnetization value can increase compared to the case where the body is made of a magnetic material. However, when the body is made of metal, the material loss may increase due to an increase in eddy current loss and high frequency hysteresis.

[0006] To reduce the loss of materials, a structure in which a polymer is used to insulate metal powder is applied. That is, the body of the power inductor is manufactured by laminating sheets in which metal powder and polymer are mixed. In addition, a predetermined base material in which a coil pattern is formed is provided in the body, and external electrodes connected to the coil pattern are provided outside the body. That is, the power inductor is manufactured by forming a coil pattern on a predetermined base material and laminating and pressing a plurality of sheets above and below the coil pattern to manufacture the body, and then forming external electrodes outside the body.

[0007] The external electrodes of the power inductor can be formed by applying a conductive paste. That is, the external electrodes are formed by applying a metal paste on both sides of the body to connect to the coil pattern. In addition, the external electrodes can be formed by further forming a plating layer on the metal paste. However, the external electrodes formed using the metal paste may be separated from the body due to weak coupling force. That is, the power inductor mounted on the electronic device may be applied with a tensile force, and since the power inductor in which the external electrodes are formed using the metal paste has a weak tensile strength, the body and the external electrodes may be separated from each other.

[0008] [Prior Art Documents]

[0009] Korean Patent Publication No. 2007-0032259 Summary of the Invention

[0010] Technical Problem

[0011] The present disclosure provides a power inductor and a method of manufacturing the same, which can improve the coupling force between the body and the external electrodes to improve the tensile strength.

[0012] The present disclosure also provides a power inductor and a method of manufacturing the same, which can improve the coupling force between the body and the extended area of the external electrodes.

[0013] Means for Solving the Problem

[0014] According to an exemplary embodiment, a power inductor includes: a body; a coil pattern provided in the body; external electrodes provided on at least one surface of the body and extending to at least another surface adjacent to the at least one surface of the body; and a coupling layer provided between the body and the extended area of the external electrodes.

[0015] The body may have inclined edges.

[0016] The power inductor may further include a surface insulating layer disposed on at least one region of the surface of the body.

[0017] The surface insulating layer may be disposed on the remaining surfaces except for the surface connecting the coil pattern to the external electrode.

[0018] The coupling layer may be disposed between the surface insulating layer and the extended region of the external electrode.

[0019] The coupling layer may include a metal or a metal alloy.

[0020] At least a part of the external electrode may include the same material as at least one of the coil pattern and the coupling layer.

[0021] The external electrode may include a first layer and at least one second layer. The first layer is configured to contact the coil pattern and the coupling layer, and the at least one second layer is disposed on the first layer and made of a material different from that of the first layer.

[0022] According to another exemplary embodiment, a method of manufacturing a power inductor includes: preparing a body in which a coil pattern is formed; forming a surface insulating layer on the surface of the body; forming a coupling layer on a predetermined region of the surface insulating layer; removing a part of the coupling layer and a part of the surface insulating layer to expose the coil pattern; and forming an external electrode on at least one surface of the body so that the external electrode is connected to the coil pattern.

[0023] The method may further include forming the edge of the body to be inclined before forming the surface insulating layer.

[0024] The external electrode may extend from at least one surface of the body to at least one surface adjacent to the at least one surface of the body.

[0025] The coupling layer may be formed on the extended region of the external electrode.

[0026] At least a part of the external electrode may be formed using the same material and the same method as at least one of the coil pattern and the coupling layer.

[0027] Effects of the invention

[0028] In a power inductor according to an exemplary embodiment, an external electrode connected to a coil pattern may be made of the same metal as the coil pattern and may be formed by the same method as the coil pattern. That is, at least a part of the thickness of the external electrode connected to the coil pattern on the side surface of the body may be formed by the same method (e.g., electroplating) as the coil pattern. Accordingly, the coupling force between the body and the external electrode may be increased, and thus the tensile strength may also be increased.

[0029] In addition, the exemplary embodiment may further include a coupling layer disposed between the external electrode and the top, bottom, front, and rear surfaces (i.e., curved portions) of the body to which the external electrode extends. Due to the provision of the coupling layer, the coupling force of the external electrode may be increased, and thus the tensile strength may also be increased.

[0030] In addition, when parylene is coated on the coil pattern, the parylene may be formed on the coil pattern with a uniform thickness, and thus the insulation property between the body and the coil pattern may be improved.

[0031] In addition, since at least two base materials are provided in the body and each of the at least two base materials has a coil pattern in a coil shape formed on at least one surface, a plurality of coils may be formed in one body, and thus the capacity of the power inductor may be increased.

[0032] In addition to the power inductor, the exemplary embodiment may also be applied to various chip components for forming external electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a perspective view of a power inductor according to an exemplary embodiment.

[0034] Figure 2 and Figure 3 is a cross-sectional view taken along line A-A' shown in accordance with an exemplary embodiment and a modified example of the exemplary embodiment. Figure 1 is a cross-sectional view taken along line A-A' shown in accordance with an exemplary embodiment and a modified example of the exemplary embodiment.

[0035] Figure 4 and Figure 5 is an exploded perspective view and a partial plan view according to an exemplary embodiment.

[0036] Figures 6 to 7 is a cross-sectional view of a coil pattern in a power inductor according to an exemplary embodiment.

[0037] Figure 8 and Figure 9 shows a cross-section of a power inductor according to the material of an insulating layer.

[0038] Figure 10Is a perspective view of a power inductor according to a modified example of an exemplary embodiment.

[0039] Figures 11 to 17 Is a cross-sectional view for sequentially illustrating a method of manufacturing a power inductor according to an exemplary embodiment.

[0040] Figure 18 Is a graph showing the tensile strength of a power inductor according to a prior art example and an exemplary embodiment.

[0041] Figure 19 Is a cross-section showing the power inductor according to an exemplary embodiment after a tensile strength experiment.

[0042] Figures 20 to 23 Is a perspective view and a cross-sectional view for illustrating a wound inductor in the process order according to another exemplary embodiment.

[0043] Figures 24 to 26 Is a cross-sectional view of a power inductor according to other exemplary embodiments. Detailed Description

[0044] Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings. However, the present disclosure may be implemented in different forms and should not be construed as limited to the embodiments presented herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] Figure 1 Is a coupled perspective view showing a power inductor according to an exemplary embodiment, and Figure 2 And Figure 3 Is a cross-sectional view taken along line A-A' shown according to an exemplary embodiment and a modified example. Figure 1 As shown in FIG. Figure 4 Is an exploded perspective view showing a power inductor according to an exemplary embodiment, Figure 5 Is a plan view showing a base material and a coil pattern, and Figure 6 And Figure 7 Is a cross-sectional view showing the base material and the coil pattern to illustrate the shape of the coil pattern. Additionally, Figure 8 And Figure 9 Is a cross-section showing the power inductor according to the material of the insulating layer. Additionally, Figure 10 Is a perspective view of a power inductor according to a modified example of an exemplary embodiment. The exemplary embodiment can be applied to a chip component for forming an external electrode, and the power inductor will be described as an exemplary embodiment.

[0046] Refer to Figure 1 And Figure 10, a power inductor according to an exemplary embodiment may include: a body 100 (100a, 100b); at least one base material 200 disposed in the body 100; coil patterns 300 (310, 320) disposed on at least one surface of the base material 200; and external electrodes 400 (410, 420) disposed outside the body 100. Additionally, the power inductor may further include an inner insulating layer 510 and a surface insulating layer 520. The inner insulating layer 510 is disposed between the coil patterns 310 and 320 and the body 100, and the surface insulating layer 520 is disposed on the surface of the body where no external electrode is provided. Additionally, the power inductor may further include a coupling layer 600. The coupling layer 600 is disposed on the remaining surfaces of the body 100 except for the two surfaces that expose the coil patterns 300, between the body 100 and the external electrodes 400. As Figure 10 shown, the power inductor may further include a top cover insulating layer 530 disposed on the top surface of the body 100.

[0047] 1. Body

[0048] The body 100 may have a hexahedron shape. However, the body 100 may have a polyhedron shape other than the hexahedron shape. Additionally, the body 100 may have chamfered edges. That is, the edges where two or three surfaces are adjacent to each other may be formed in an inclined manner. The edges may be formed to have a predetermined inclination without a right angle, or may be formed in a circular manner. Here, at least a part of the inclined or circular edges may have different inclinations. The above-mentioned body 100 may contain metal powder 110 and insulating material 120 as Figure 2 shown and may further contain a heat conductive filler 130 as Figure 3 shown.

[0049] The metal powder 110 may have an average particle diameter of approximately 1 micron to approximately 100 microns. Additionally, the metal powder 110 may use a single type or at least two types of particles of the same size or a single type or at least two types of particles of multiple sizes. For example, a first metal powder having an average particle diameter of approximately 20 microns to approximately 100 microns, a second metal powder having an average particle diameter of approximately 2 microns to approximately 20 microns, and a third metal powder having an average particle diameter of approximately 1 micron to approximately 10 microns may be mixed and used. That is, the metal powder 110 may include: a first metal powder, wherein the median value D50 of the average particle diameter or particle size distribution is approximately 20 microns to approximately 100 microns; a second metal powder, wherein the median value D50 of the average particle diameter or particle size distribution is approximately 2 microns to approximately 20 microns; and a third metal powder, wherein the median value D50 of the average particle diameter or particle size distribution is approximately 1 micron to approximately 10 microns. Here, the first metal powder may be larger than the second metal powder, and the second metal powder may be larger than the third metal powder. Here, the metal powder may be the same type of powder or different types of powder. Additionally, the mixing ratio of the first metal powder, the second metal powder, and the third metal powder may be, for example, 5 to 9:0.5 to 2.5:0.5 to 2.5, preferably 7:1:2. That is, for approximately 100 wt% of the metal powder 110, approximately 50 wt% to approximately 90 wt% of the first metal powder, approximately 5 wt% to approximately 25 wt% of the second metal powder, and approximately 5 wt% to approximately 25 wt% of the third metal powder may be mixed. Here, the contained first metal powder may be more than the second metal powder, and the contained second metal powder may be equal to or less than the third metal powder. Preferably, for approximately 100 wt% of the metal powder 110, approximately 70 wt% of the first metal powder, approximately 10 wt% of the second metal powder, and approximately 20 wt% of the third metal powder may be mixed. Since the metal powder 110, in which metal powders having at least two, and preferably three or more average particle diameters are uniformly mixed together, is distributed throughout the body 100, the magnetic permeability may be uniform throughout the body 100. When using at least two metal powders 110 having different sizes from each other, the filling rate of the body 100 may be increased to maximize the capacity. For example, in the case of using a metal powder having an average size of approximately 30 microns, pores may be generated between the metal powders, and thus the filling rate may be reduced. However, when a metal powder having a size of approximately 3 microns is mixed between the metal powders having a size of approximately 30 microns, the filling rate of the metal powder in the body 100 may be increased. The metal powder 110 may use a metal material containing iron (Fe).For example, the metal powder 110 may include at least one metal selected from the group consisting of the following materials: iron-nickel (Fe-Ni), iron-nickel-silicon (Fe-Ni-Si), iron-aluminum-silicon (Fe-Al-Si), and iron-aluminum-chromium (Fe-Al-Cr). That is, the metal powder 110 may include iron to have a magnetic composition or may be formed of a magnetic metal alloy to have a predetermined magnetic permeability. Additionally, the surface of the metal powder 110 may be coated with a magnetic material having a magnetic permeability different from that of the metal powder 110. For example, the magnetic material may include a metal oxide magnetic material. The metal oxide magnetic material may include at least one selected from the group consisting of the following materials: nickel oxide magnetic material, zinc oxide magnetic material, copper oxide magnetic material, magnesium oxide magnetic material, cobalt oxide magnetic material, barium oxide magnetic material, and nickel-zinc-copper oxide magnetic material. That is, the magnetic material coated on the surface of the metal powder 110 may be formed of a metal oxide containing iron and preferably has a magnetic permeability greater than that of the metal powder 110. Since the metal powder 110 has magnetism, when the metal powders 110 come into contact with each other, the insulation between the metal powders 110 may be broken and a short circuit may occur. Therefore, the surface of the metal powder 110 may be coated with at least one insulating material. For example, the surface of the metal powder 110 may be coated with an oxide or an insulating polymer material (such as parylene). Here, parylene is preferred. Parylene may be coated with a thickness of approximately 1 micron to approximately 10 microns. Here, when parylene is coated with a thickness less than approximately 1 micron, the insulation effect of the metal powder 110 may deteriorate, and when parylene is coated with a thickness greater than approximately 10 microns, the magnetic permeability may decrease as the size of the metal powder 110 increases and the distribution of the metal powder 110 in the body 100 decreases. Additionally, in addition to parylene, the surface of the metal powder 110 may also be coated with various insulating polymer materials. The oxide coated onto the metal powder 110 may be formed by oxidizing the metal powder 110. As an alternative, the metal powder 110 may be coated with at least one selected from the group consisting of the following materials: TiO2, SiO2, ZrO2, SnO2, NiO, ZnO, CuO, CoO, MnO, MgO, Al2O3, Cr2O3, Fe2O3, B2O3, and Bi2O3. Here, the metal powder 110 may be coated with an oxide having a double structure (for example, a double structure formed of an oxide and a polymer material). As an alternative, the surface of the metal powder 110 may be coated with a magnetic material and then coated with an insulating material. Since the surface of the metal powder 110 is coated with an insulating material, a short circuit caused by contact between the metal powders 110 can be prevented.Here, the metal powder 110 is coated with an oxide or an insulating polymer material or a dual structure of a magnetic material and an insulating material having a thickness of approximately 1 μm to approximately 10 μm.

[0050] The insulating material 120 can be mixed with the metal powder 110 to insulate the metal powders 110 from each other. That is, the metal powder 110 can increase eddy current loss and high-frequency hysteresis, thereby causing loss of the material. To reduce the loss of the material, the insulating material 120 can be included to insulate the metal powders 110 from each other. The insulating material 120 can include at least one selected from the group consisting of: epoxy resin, polyimide, and liquid crystalline polymer (LCP). However, the exemplary embodiments are not limited thereto. Additionally, the insulating material 120 can be made of a thermosetting resin for providing insulating properties between the metal powders 110. For example, the thermosetting resin can include at least one selected from the group consisting of: novolac epoxy resin, phenoxy-type epoxy resin, BPA-type epoxy resin, BPF-epoxy resin, hydrogenated BPA epoxy resin, dimer acid modified epoxy resin, urethane modified epoxy resin, rubber modified epoxy resin, and DCPD-type epoxy resin. Here, the insulating material 120 can be included in an amount of approximately 2.0 wt% to approximately 5.0 wt% based on approximately 100 wt% of the metal powder 110. However, when the content of the insulating material 120 increases, since the volume fraction of the metal powder 110 decreases, the effect of increasing the saturation magnetization value may not be appropriately achieved, and the magnetic permeability of the body 100 may decrease. On the contrary, when the content of the insulating material 120 decreases, since strong acid or strong base solutions used in the process of manufacturing the inductor are introduced into the metal powder 110, the inductance characteristics may decrease. Therefore, the included insulating material 120 can be within a range that does not decrease the saturation magnetization value and the inductance of the metal powder 110.

[0051] However, there are the following limitations: The inductance of the power inductor made of the metal powder 110 and the insulating material 120 decreases as the temperature increases. That is to say, there are the following limitations: The temperature of the power inductor increases due to the heat generated by the electronic device applying the power inductor, and thus, while the metal powder 110 forming the body of the power inductor is heated, the inductance decreases. To solve the above limitation that the body 100 is heated by external heat, the body 100 may include a thermal conductive filler 130. That is to say, when the metal powder 110 of the body 100 is heated by external heat, since the thermal conductive filler 130 is included, the heat of the metal powder 110 can be discharged to the outside. Although the thermal conductive filler 130 may include at least one selected from the group consisting of the following materials: MgO, AlN, carbon-based materials, nickel-based materials, and manganese-based materials, the exemplary embodiments are not limited thereto. Here, the carbon-based materials may include carbon and have various shapes. For example, the carbon-based materials may include graphite, carbon black, graphene, etc. In addition, nickel-based ferrites may include NiO, ZnO, and CuO-Fe2O3, and manganese-based ferrites may include MnO, ZnO, and CuO-Fe2O3. Since the thermal conductive filler is made of a ferrite material, an increase or decrease in magnetic permeability can be preferably prevented. The above thermal conductive filler 130 may be distributed in powder form and included in the insulating material 120. In addition, the thermal conductive filler 130 may be included in an amount of approximately 0.5 wt% to approximately 3 wt% based on approximately 100 wt% of the metal powder 110. When the content of the thermal conductive filler 130 is less than the above range, the heat dissipation effect can be achieved, and when the content of the thermal conductive filler 130 is greater than the above range, as the content of the metal powder 110 decreases, the magnetic permeability of the body 100 decreases. In addition, the thermal conductive filler 130 may have a size of, for example, approximately 0.5 microns to approximately 100 microns. That is to say, the thermal conductive filler 130 may have the same size as the metal powder 110 or a size smaller than the metal powder 110. The heat dissipation effect of the thermal conductive filler 130 can be adjusted according to the size and content of the thermal conductive filler 130. For example, when the size and content of the thermal conductive filler increase, the heat dissipation effect can be enhanced. The body 100 can be manufactured by laminating a plurality of sheets made of materials including the metal powder 110, the insulating material 120, and the thermal conductive filler 130. Here, when the plurality of sheets are laminated to manufacture the body 100, the content of the thermal conductive filler 130 in each of the sheets may be different. For example, when the thermal conductive filler 130 gradually moves away from the center of the base material 200 upward and downward, the content of the thermal conductive filler 130 in the sheet may gradually increase. That is to say, the content of the thermal conductive filler 130 may be different in the vertical direction (i.e., the Z direction). In addition, the content of the thermal conductive filler 130 may be different in the horizontal direction (i.e., at least one of the X direction and the Y direction). That is to say, within the same sheet, the content of the thermal conductive filler 130 may be different.In addition, the main body 100 can be manufactured by applying various methods as needed, such as printing a paste made of metal powder 110, insulating material 120, and heat-conductive filler 130 with a predetermined thickness, or pressing the paste into a frame. Here, the number of laminated sheets used to form the main body 100 or the thickness of the paste printed with a predetermined thickness can be appropriately determined in consideration of electrical characteristics such as the inductance required for a power inductor. In an exemplary embodiment, the main body 100 further includes a heat-conductive filler as a modified example. Although the heat-conductive filler is not mentioned in another exemplary embodiment below, it should be understood that the main body 100 also includes a heat-conductive filler.

[0052] The main bodies 100a and 100b disposed above and below the base material 200 and sandwiching the base material 200 therebetween can be connected to each other through the base material. That is, a part of the base material can be removed, and a part of the main body 100 can be filled in the removed part. Since at least a part of the base material 200 is removed and the main body is filled in the removed part, the area of the base material 200 is reduced and the ratio of the main body 100 increases by the same amount. Therefore, the magnetic permeability of the power inductor can be increased.

[0053] 2. Base Material

[0054] The base material 200 can be disposed in the body 100. For example, the base material 200 can be disposed in the body 100 in the longitudinal direction of the body 100 (i.e., in the direction toward the external electrode 400). Here, at least one base material 200 can be provided. For example, at least two base materials 200 can be spaced apart from each other by a predetermined distance in a direction perpendicular to the direction in which the external electrode 400 is disposed (e.g., in the vertical direction). As another alternative, two or more base materials can be arranged in the direction in which the external electrode 400 is disposed. For example, the base material 200 can be made of a copper clad lamination (CCL) or a metal magnetic material. Here, when the base material 200 is formed of a metal magnetic material, the magnetic permeability can be increased and the capacitance can be easily achieved. That is, CCL is made by bonding a copper foil to glass-reinforced fibers, and since CCL does not have magnetic permeability, the magnetic permeability of the power inductor may deteriorate. However, when the base material 200 is made of a metal magnetic material, since the metal magnetic material has magnetic permeability, the magnetic permeability of the power inductor may not deteriorate. The base material 200 using a metal magnetic material can be manufactured by bonding a copper foil to a plate having a predetermined thickness made of a metal containing iron (e.g., at least one metal selected from the group consisting of iron-nickel (Fe-Ni), iron-nickel-silicon (Fe-Ni-Si), iron-aluminum-silicon (Fe-Al-Si), and iron-aluminum-chromium (Fe-Al-Cr)). That is, the manufacturing method of the base material 200 can be: manufacturing an alloy formed of at least one metal containing iron into a plate shape having a predetermined thickness, and then bonding a copper foil to at least one surface of the metal plate.

[0055] In addition, at least one via hole 210 can be defined in a predetermined region of the base material 200, and the coil pattern 310 and the coil pattern 320 disposed above and below the base material 200 can be electrically connected to each other through the via hole 210. The manufacturing method of the via hole 210 can be: forming a through hole (not shown) passing through the base material 200 in the thickness direction in the base material 200 and then filling the through hole with a paste. Here, at least one of the coil pattern 310 and the coil pattern 320 can grow from the via hole 210, and thus, the via hole 210 and at least one of the coil pattern 310 and the coil pattern 320 can be integrally formed with each other. In addition, at least a part of the base material 200 can be removed. That is, at least a part of the base material 200 can be removed or not removed. Preferably, as Figure 4 and Figure 5As shown, the remaining regions of the base material 200 except for the regions overlapping with the coil patterns 310 and 320 can be removed. For example, the regions of the base material 200 disposed within the coil patterns 310 and 320 having spiral shapes respectively can be removed to define the through holes 220, or the regions of the base material 200 disposed outside the coil patterns 310 and 320 can be removed. That is, the base material 200 can have a track shape, for example, along the outer shape of each of the coil patterns 310 and 320, and the regions facing the external electrodes 400 can have a linear shape along the shape of the ends of each of the coil patterns 310 and 320. Therefore, the outer side of the base material 200 can have a curved shape relative to the edge of the body 100. As Figure 5 As shown, the body 100 can be filled in the portion where the base material 200 has been removed. That is, the upper body 100a and the lower body 100b can be connected to each other through the removed region of the base material 200 including the through holes 220. Additionally, when the base material 200 is made of a metal magnetic material, the base material 200 can be in contact with the metal powder 110. To solve the above limitations, an inner insulating layer 510 (e.g., parylene) can be provided on the side surface of the base material 200. For example, the inner insulating layer 510 can be provided on the side surface of the through holes 220 and the outer surface of the base material 200. Here, the width of the base material 200 can be larger than the width of each of the coil patterns 310 and 320. For example, the base material 200 can reserve a predetermined width directly below the coil patterns 310 and 320. For example, the base material 200 can protrude approximately 0.3 micrometers from the coil patterns 310 and 320. When the regions of the base material 200 disposed inside and outside the coil patterns 310 and 320 are removed, the base material 200 can have a region smaller than the cross-section of the body 100. For example, when the area of the cross-section of the body 100 is approximately 100, the base material 200 can have an area ratio of approximately 40 to approximately 80. When the area ratio of the base material 200 is high, the magnetic permeability of the body can decrease, and when the area ratio of the base material 200 is low, the formation area of the coil patterns 310 and 320 can decrease. Therefore, the area ratio of the base material 200 can be adjusted in consideration of the magnetic permeability of the body 100, the line width and the number of turns of each of the coil patterns 310 and 320, etc.

[0056] 3. Coil Pattern

[0057] The coil patterns 300 (310, 320) can be disposed on at least one surface of the substrate material 200, and preferably, can be disposed on both surfaces of the substrate material 200. Each of the coil patterns 310, 320 can have a spiral shape in an outward direction starting from a predetermined region of the substrate material 200 (e.g., from the central portion of the substrate material 200), and the two coil patterns 310, 320 disposed on the substrate material 200 can be connected to each other to form one coil. That is, the coil pattern 310 and the coil pattern 320 can have a spiral shape formed on the central portion of the substrate material 200 from the outside of the through hole 220, and can be connected to each other through the via hole 210 defined in the substrate material 200. Here, the upper coil pattern 310 and the lower coil pattern 320 can have the same shape and the same height. In addition, the coil pattern 310 and the coil pattern 320 can overlap each other. As another alternative, the coil pattern 320 can be disposed to overlap with a region where the coil pattern 310 is not provided above. Each of the coil patterns 310 and the coil pattern 320 can have an end portion having a linear shape extending to the outside. The end portion can extend along the central portion of the short side of the body 100. As Figure 4 and Figure 5 shown, the region of each of the coil patterns 310 and the coil pattern 320 that contacts the external electrode 400 can have a larger width than other regions. Since a part of each of the coil patterns 310 and the coil pattern 320 (i.e., the withdrawal portion) has a wider width, the contact area between the coil patterns 310 and 320 and the external electrode 400 can be increased, and thus, the resistance can be reduced. As another alternative, each of the coil patterns 310 and the coil pattern 320 can extend in the width direction of the external electrode 400 on a region where the external electrode 400 is provided above. Here, the end portion of each of the coil patterns 310 and the coil pattern 320 (i.e., the withdrawal portion led out to the external electrode 400) can have a linear shape toward the central portion of the side surface of the body 100.

[0058] The coil patterns 310 and 320 can be electrically connected to each other through the vias 210 defined in the substrate material 200. The coil patterns 310 and 320 can be formed by various methods, such as thick-film printing, coating, deposition, plating, and sputtering. Here, the plating method is preferred. In addition, the coil patterns 310 and 320 and the vias 210 can be made of a material including at least one of silver (Ag), copper (Cu), and copper alloys. However, the exemplary embodiments are not limited thereto. When the coil patterns 310 and 320 are formed by a plating process, a coupling layer (such as a copper layer) is formed on the substrate material 200 through the plating process and then the coupling layer (such as the copper layer) is patterned through a lithography process. That is, a copper foil disposed on the surface of the substrate material 200 can be used as a seed layer to form the copper layer, and then the copper layer is patterned to form the coil patterns 310 and 320. As another alternative, a photosensitive film pattern having a predetermined shape can be formed on the substrate material 200, and then a plating process can be performed on the photosensitive film pattern to grow a coupling layer from the exposed surface of the substrate material 200, and then the photosensitive film is removed, thereby forming the coil patterns 310 and 320 each having a predetermined shape. In addition, each of the coil patterns 310 and 320 can be formed to have a multilayer structure. That is, a plurality of coil patterns can be further disposed above the coil pattern 310 disposed above the substrate material 200, and a plurality of coil patterns can be further disposed below the coil pattern 320 disposed below the substrate material 200. When the coil patterns 310 and 320 are formed to have a multilayer structure, an insulating layer can be disposed between the lower layer and the upper layer. Then, vias (not shown) can be defined in the insulating layer to connect the multilayer coil patterns to each other. The height of each of the coil patterns 310 and 320 can be approximately 2.5 times greater than the thickness of the substrate material 200. For example, the substrate material 200 has a thickness of approximately 10 micrometers to approximately 50 micrometers, and each of the coil patterns 310 and 320 can have a height of approximately 50 micrometers to approximately 300 micrometers.

[0059] In addition, each of the coil patterns 310 and 320 according to the exemplary embodiments can have a dual structure. That is, as Figure 6As shown, the coil pattern may include a first plating layer 300a and a second plating layer 300b covering the first plating layer 300a. Here, the second plating layer 300b covers the top surface and the side surface of the first plating layer 300a. The thickness on the top surface of the second plating layer 300b may be greater than the thickness on the side surface of the first plating layer 300a. The first plating layer 300a may have a predetermined inclination on its side surface, and the second plating layer 300b may have an inclination smaller than the inclination of the side surface of the first plating layer 300a. That is, the side surface of the first plating layer 300a has an obtuse angle with respect to the surface of the base material 200 disposed outside the first plating layer 300a, and the angle of the second plating layer 300b may be smaller than the angle of the first plating layer 300a, preferably a right angle. As Figure 7As shown, the ratio between the width a of the top surface and the width b of the bottom surface of the first plating layer 300a can be from 0.2:1 to 0.9:1, preferably from 0.4:1 to 0.8:1. Additionally, the ratio between the width a of the first plating layer 300a and its height can be from 1:0.7 to 1:4, preferably from 1:1 to 1:2. That is, the first plating layer 300a can have a width that gradually decreases from the bottom surface to the top surface, and thus, the side surface can have a predetermined inclination. A main plating process can be performed, and then an etching process can be performed to make the first plating layer 300a have a predetermined inclination. Additionally, the second plating layer 300b covering the first plating layer 300a has an approximately rectangular shape, in which the side surfaces are preferably formed vertically, and a small rounded portion is formed between the top surface and the side surfaces. Here, the shape of the second plating layer 300b can be determined according to the ratio between the width a of the top surface of the first plating layer 300a and the width b of the bottom surface of the first plating layer 300a (i.e., the ratio of a:b). For example, when the ratio a:b between the width a of the top surface of the first plating layer 300a and the width b of the bottom surface of the first plating layer 300a increases, the ratio between the width c of the top surface and the width d of the bottom surface of the second plating layer 300b increases. However, when the ratio a:b between the width a of the top surface of the first plating layer 300a and the width b of the bottom surface of the first plating layer 300a is greater than 0.9:1, the second plating layer 300b can be formed such that the width of the bottom surface is greater than the width of the top surface, and the side surface forms an acute angle with the base material 200. Additionally, when the ratio a:b between the width of the top surface of the first plating layer 300a and the width of the bottom surface of the first plating layer 300a is less than 0.2:1, the second plating layer can be formed such that the top surface is rounded from a predetermined area of the side surface. Therefore, the ratio between the top surface and the bottom surface of the first plating layer 300a is preferably adjusted so that the top surface has a wide width and has vertical side surfaces. Additionally, the ratio between the width b of the bottom surface of the first plating layer 300a and the width d of the bottom surface of the second plating layer 300b can be from 1:1.2 to 1:2, and the ratio between the width b of the bottom surface of the first plating layer 300a and the distance e between adjacent first plating layers 300a can be from 1.5:1 to 3:1. Here, the second plating layers 300b do not contact each other. The ratio between the width of the top surface and the width of the bottom surface of the coil pattern 300 (which includes the first plating layer 300a and the second plating layer 300b) can be from 0.5:1 to 0.9:1, preferably from 0.6:1 to 0.8:1. That is, the ratio between the top surface and the bottom surface of the external shape of the coil pattern 300 (i.e., the external shape of the second plating layer 300b) can be from 0.5 to 0.9:1.Accordingly, with respect to an ideal rectangular shape having right angles, the circular area of the edges of the top surface of the coil pattern 300 may be less than approximately 0.5. For example, with respect to an ideal rectangular shape having right angles, the circular area may be equal to or greater than approximately 0.001 and less than approximately 0.5. Additionally, with respect to the ideal rectangular shape, the resistance of the coil pattern 300 according to the exemplary embodiment does not change significantly. For example, when the ideal rectangular shape coil pattern has a resistance of approximately 100, the coil pattern 300 according to the exemplary embodiment may maintain a resistance of approximately 101 to approximately 110. That is, the coil pattern 300 according to the exemplary embodiment may maintain its resistance at approximately 101% to approximately 110% of the resistance of the ideal rectangular shape coil pattern according to the shape of the first plating layer 300a and the shape of the second plating layer 300b that varies based on the shape of the first plating layer 300a. The second plating layer 300b may be formed using the same plating solution as the first plating layer 300a. For example, the first plating layer 300a and the second plating layer 300b may use a plating solution based on copper sulfate and sulfuric acid, and the plating solution may have improved plating properties by adding chlorine (Cl) and an organic compound to the plating solution. The organic compound may use a gloss agent and a carrier containing polyethylene glycol (PEG) to improve the uniformity, electrodeposition characteristics, and gloss characteristics of the plating layer.

[0060] In the coil pattern 300, the second plating layer 300b disposed on the first plating layer 300a may have a lower width A, a center width B, and an upper width C, and at least a part of the lower width A, the center width B, and the upper width C is different in the vertical direction of the second plating layer 300b. Here, the center width B may be equal to or greater than the lower width A and equal to or greater than the upper width C. Additionally, the lower width A may be equal to or greater than the upper width C. For example, the center width B may be greater than each of the lower width A and the upper width C or equal to the lower width A and greater than the upper width C. As another alternative, the lower width A, the center width B, and the upper width C may all be the same as each other. Here, the lower part may refer to a height of approximately 10% of the height of the second plating layer 300b, the center part may refer to a height of approximately 10% to approximately 80% of the height of the second plating layer 300b, and the upper part may refer to the height up to the circular part.

[0061] In addition, the coil pattern 300 can be formed by laminating at least two plating layers. Here, each of the plating layers can have vertical side surfaces and the same shape and thickness. That is, the coil pattern 300 can be formed on the seed layer through a plating process. For example, the coil pattern 300 can be formed by laminating three plating layers on the seed layer. The above coil pattern 300 can be formed by an anisotropic plating process and has an aspect ratio of approximately 2 to approximately 10.

[0062] In addition, the coil pattern 300 can have a shape in which the width gradually decreases from the innermost perimeter to the outermost perimeter. That is, n coil patterns 300 having a spiral shape can be formed from the innermost perimeter to the outermost perimeter. For example, when forming four patterns, the width of each of the patterns can gradually increase from the first pattern (i.e., the innermost perimeter pattern), the second pattern, the third pattern, and the fourth pattern (i.e., the outermost perimeter pattern). For example, when the first pattern has a width of 1, the second pattern can have a ratio of 1 to 1.5, the third pattern can have a ratio of 1.2 to 1.7, and the fourth pattern can have a ratio of 1.3 to 2. That is, the first pattern to the fourth pattern can have a ratio of 1:1 to 1.5:1.2 to 1.7:1.3 to 2. In other words, the width of the second pattern can be equal to or greater than the first pattern, the width of the third pattern can be greater than the first pattern and equal to or greater than the second pattern, and the width of the fourth pattern can be greater than each of the first pattern and the second pattern and equal to or greater than the third pattern. In order for the width of the coil pattern to gradually increase from the innermost perimeter to the outermost perimeter, the seed layer can have a width that gradually increases from the innermost perimeter to the outermost perimeter. In addition, at least one region of the coil pattern can have different widths in the vertical direction. That is, the lower part, the central part, and the upper part of at least one region can have different widths.

[0063] 4. External Electrode

[0064] The external electrodes 400 (410, 420) can be disposed on two surfaces of the body 100 that face each other. For example, the external electrodes 400 can be disposed on two side surfaces of the body 100 that face each other in the X direction. The external electrodes 400 can be electrically connected to the coil patterns 310, 320 of the body 100. Additionally, the external electrodes 400 can be formed on all of the two side surfaces of the body 100 and contact the coil pattern 310 and the coil pattern 320 at the central portions of the two side surfaces. That is, when the ends of the coil pattern 310 and the ends of the coil pattern 320 are exposed to the outside of the body 100 and the external electrodes 400 are disposed on the side surfaces of the body 100, the external electrodes 400 can be connected to the coil patterns 310, 320. The external electrodes 400 can be formed by various methods (such as deposition, sputtering, and plating) using conductive epoxy resin and conductive paste. The external electrodes 400 can be disposed only on the two side surfaces and the bottom surface of the body 100 or even on the top surface or the front surface of the body 100. For example, the external electrodes 400 can be disposed not only on the two side surfaces in the X direction but also on the front and rear surfaces in the Y direction and the top and bottom surfaces in the Z direction. That is, the external electrodes 400 can be disposed on the two side surfaces in the X direction, on the bottom surface mounted on the printed circuit board, and on other regions depending on the forming method or process conditions. Additionally, each of the external electrodes 400 can be formed by mixing a multi-component glass frit (such as approximately 0.5% to approximately 20%) mainly composed of Bi2O3 or SiO2 with metal powder. That is, a part of the external electrode 400 that contacts the body 100 can be made of a conductive material mixed with glass. Here, the mixture of the glass frit and the metal powder can be prepared in a paste form and coated on the two surfaces of the main body 100. That is, when a part of the external electrode 400 is made of conductive paste, the conductive paste can be mixed with the glass frit. Since the glass frit is included in the external electrodes 400, the adhesion between the external electrodes 400 and the body 100 can be improved, and the contact reaction between the coil pattern 300 and the external electrodes 400 can be improved.

[0065] The external electrode 400 can be made of a conductive metal. For example, the external electrode 400 can be made of at least one selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and their alloys. Here, in an exemplary embodiment, at least a part of the external electrode 400 connected to the coil pattern 300 (i.e., the first layers 411, 421 provided on the surface of the body 100 and connected to the coil pattern 300) can be made of the same material as the coil pattern 300. For example, if the coil pattern 300 is made of copper, at least a part of the external electrode 400 (i.e., the first layers 411, 421) can be made of copper. Here, as described above, copper can be provided by an impregnation or printing method using a conductive paste or by methods such as deposition, sputtering, and plating. However, in a preferred embodiment, at least the first layers 411, 421 of the external electrode 400 can be formed by the same method as the coil pattern 300 (i.e., plating). That is, the entire thickness of the external electrode 400 can be formed by copper plating, or a partial thickness of the external electrode 400 (i.e., the first layers 411, 421 connected to the coil pattern 300 to contact the surface of the body 100) can be formed by copper plating. To form the external electrode 400 by a plating process, the forming method of the external electrode 400 can be: forming a seed layer on the two side surfaces of the body 100, and then forming a plating layer from the seed layer. As an alternative, when the coil pattern 300 exposed to the outside of the body 100 is used as a seed, the external electrode 400 can be formed without forming a separate seed layer by plating. Here, an acid treatment process can be performed before the plating process. That is, at least a part of the surface of the body 100 can be treated with hydrochloric acid, and then the plating process can be performed. Although the external electrode 400 is formed by plating, the external electrode 400 can be provided on the two opposite side surfaces of the body 100 and can extend to other side surfaces (i.e., the top surface and the bottom surface) adjacent to the two side surfaces. Here, at least a part of the external electrode 400 connected to the coil pattern 300 can be the entire side surface of the body 100 or a partial area of the body 100. As an alternative, the external electrode 400 can further include at least one plating layer. That is, the external electrode 400 can include the first layers 411, 421 connected to the coil pattern 300 and at least one second layer 412, 422 provided on the first layers 411, 421. That is, the second layer 412, 422 can be one layer or two or more layers. For example, the external electrode 400 can be formed to further form at least one of a nickel plating layer (not shown) and a tin plating layer (not shown) on the copper plating layer. That is, the external electrode 400 can have a laminated structure formed by a copper layer, a nickel plating layer, and a tin plating layer, or can have a laminated structure formed by a copper layer, a nickel plating layer, and a tin / silver plating layer. Here, the plating can be performed by electroplating or electroless plating.That is, the first layers 411 and 421 can be formed such that a partial thickness is formed by electroless plating and the remaining thickness is formed by electroplating, or the entire thickness is formed by electroless plating or electroplating. That is, the second layers 412 and 422 can be formed such that a partial thickness is formed by electroless plating and the remaining thickness is formed by electroplating, or the entire thickness is formed by electroless plating or electroplating. As another alternative, the first layers 411 and 421 can be formed by electroless plating or electroplating, and the second layers 412 and 422 can be formed by electroless plating or electroplating in the same manner as the first layers 411 and 421 or can be formed by electroless plating or electroplating in a manner different from that of the first layers 411 and 421. The tin plating layer of the second layers 412 and 422 can have a thickness equal to or greater than that of the nickel plating layer. For example, the external electrode 400 can have a thickness of approximately 2 micrometers to approximately 100 micrometers, where the first layers 411 and 421 can have a thickness of approximately 1 micrometer to approximately 50 micrometers, and the second layers 412 and 422 can have a thickness of approximately 1 micrometer to approximately 50 micrometers. Here, in the external electrode 400, the first layers 411 and 421 and the second layers 412 and 422 can have the same thickness or different thicknesses. When the first layers 411 and 421 and the second layers 412 and 422 have different thicknesses, the first layers 411 and 421 can be thicker or thinner than the second layers 412 and 422. In an exemplary embodiment, the first layers 411 and 421 have a thickness smaller than that of the second layers 412 and 422. The second layers 412 and 422 can be formed such that the nickel plating layer is formed to have a thickness of approximately 1 micrometer to approximately 10 micrometers, and the tin plating layer or the tin / silver plating layer is formed to have a thickness of approximately 2 micrometers to approximately 10 micrometers.

[0066] As described above, since at least a partial thickness of the external electrode 400 is made of the same material and by the same method as the coil pattern 300, the coupling force between the body 100 and the external electrode 400 can be improved. That is, when at least a part of the external electrode 400 is formed by copper plating, the coupling force between the coil pattern 300 and the external electrode 400 can be improved. Additionally, since the external electrode 400 is disposed on partial regions of the body 100 in the Y direction and the Z direction to form a bent portion, the coupling force between the electrode 400 and the body 100 can be improved. The power inductor according to the exemplary embodiment can have a tensile strength of approximately 2.5 kilogram-force (kgf) to approximately 4.5 kilogram-force. Therefore, according to the exemplary embodiment, compared with the prior art, the tensile strength can be further improved, and thus the body 100 can not be separated from the electronic device on which the power inductor according to the exemplary embodiment is mounted. That is, while the external electrode 400 remains mounted to the electronic device, the body 100 can not be separated from the external electrode 400.

[0067] 5. Inner Insulating Layer

[0068] The inner insulating layer 510 may be disposed between the coil patterns 310 and 320 and the body 100 to insulate the coil patterns 310 and 320 from the metal powder 110. That is, the inner insulating layer 510 may cover the top surface and the side surfaces of the coil patterns 310 and 320. Additionally, in addition to the top surface and the side surfaces of the coil patterns 310 and 320, the inner insulating layer 510 may cover the base material 200. That is, the inner insulating layer 510 may be disposed on the exposed area (i.e., the surface and the side surfaces of the base material 200) of the base material 200 that is farther from the coil patterns 310 and 320 in a predetermined removed area. The inner insulating layer 510 located on the base material 200 may have the same thickness as the inner insulating layer 510 located on the coil patterns 310 and 320. The inner insulating layer 510 may be formed by coating parylene on the coil patterns 310 and 320. For example, when the base material 200 having the coil patterns 310 and 320 formed thereon is prepared in a deposition chamber and then parylene is vaporized and supplied into a vacuum chamber, parylene may be deposited on the coil patterns 310 and 320. For example, parylene may be initially heated in a vaporizer and vaporized into a dimer state, and then secondarily heated and thermally decomposed into a monomer state, and when parylene is cooled using a cold trap and a mechanical vacuum pump connected to the deposition chamber, parylene may be converted from the monomer state to a polymer state and deposited on the coil patterns 310 and 320. As an alternative, the inner insulating layer 510 may be made of an insulating polymer other than parylene (e.g., at least one selected from the group consisting of epoxy resin, polyimide, and liquid crystal polymer). However, when parylene is coated, the inner insulating layer 510 may be formed on the coil patterns 310 and 320 with a uniform thickness, and although parylene is formed with a small thickness, parylene may further improve the insulation characteristics compared to other materials. That is, when parylene is coated to form the inner insulating layer 510, the inner insulating layer 510 may have a thickness smaller than the thickness when polyimide is coated to form the inner insulating layer 510 and the insulation breakdown voltage may increase. Therefore, the insulation characteristics may be improved. Additionally, a uniform thickness may be formed by filling a part between the patterns according to the distance between the patterns of the coil patterns 310 and 320, or a uniform thickness may be formed along the stepped portion between the patterns. That is, when the distance between the patterns of the coil patterns 310 and 320 is large, parylene may be coated with a uniform thickness along the stepped portion between the patterns, and when the distance between the patterns is small, the portion between the patterns may be filled to form a predetermined thickness on the coil patterns 310 and 320. Figure 8is a cross-section of a power inductor showing that the insulating layer is made of polyimide, and Figure 9 is a cross-section of a power inductor showing that the insulating layer is made of parylene. As Figure 9 shown, in the case of parylene, the insulating layer has a small thickness along the stepped portions of the coil pattern 310 and the coil pattern 320. However, in the case of polyimide, the insulating layer has a greater thickness than in the case of parylene. By using parylene, the inner insulating layer 510 can have a thickness of approximately 3 micrometers to approximately 100 micrometers. When the inner insulating layer 510 made of parylene has a thickness less than approximately 3 micrometers, the insulating properties may deteriorate, and when the inner insulating layer 510 has a thickness greater than approximately 100 micrometers, as the thickness occupied by the inner insulating layer 510 within the same size increases, the volume of the body 100 decreases, and thus the magnetic permeability may decrease. As an alternative, the inner insulating layer 510 can be manufactured as a sheet having a predetermined thickness and then formed on the coil pattern 310 and the coil pattern 320.

[0069] 6. Surface insulating layer

[0070] A surface insulating layer 520 may be formed on the surface of the body 100. Here, the surface insulating layer 520 may be formed on the remaining surfaces of the body 100 except for the two opposite side surfaces thereof. That is, the coil pattern 300 may be exposed to the two opposite side surfaces of the body 100 (for example, the two side surfaces in the X direction), and the surface insulating layer 520 may be formed on the remaining surfaces except for the two side surfaces to which the coil pattern 300 is exposed. In other words, the surface insulating layer 520 may be formed on the remaining regions of the body 100 except for the two side surfaces while contacting the surface. For example, the surface insulating layer 520 may be formed on the two surfaces opposite to each other in the Y direction (i.e., the front surface and the rear surface), and on the two surfaces opposite to each other in the Z direction (i.e., the bottom surface and the top surface). The surface insulating layer 520 may be formed to form the external electrode 400 at a desired position by a plating process. That is, since the surface resistance is almost the same on the body 100, when the plating process is performed, the plating process may be performed on the entire surface of the body. Therefore, when the surface insulating layer 520 is formed on the region where the external electrode 400 is not formed, the external electrode 400 may be formed at a desired position. The surface insulating layer 520 may be made of an insulating material, for example, it may be made of one selected from the group consisting of: epoxy resin, polyimide, and liquid crystal polymer (LCP). In addition, the surface insulating layer 520 may be made of a thermosetting resin. For example, the thermosetting resin may include at least one selected from the group consisting of: novolac epoxy resin, phenoxy type epoxy resin, BPA type epoxy resin, BPF type epoxy resin, hydrogenated BPA epoxy resin, dimer acid modified epoxy resin, urethane modified epoxy resin, rubber modified epoxy resin, and DCPD type epoxy resin. That is, the surface insulating layer 520 may be made of the insulating material 120 of the body 100. The surface insulating layer 520 may be formed by coating or printing a polymer or a thermosetting resin on a predetermined region of the body 100. That is, the surface insulating layer 520 may be formed on the four surfaces in the Y direction and the Z direction. As another alternative, the surface insulating layer 520 may be formed on the entire surface of the body 100, and then the surface insulating layer 520 on the two opposite side surfaces in the X direction of the body 100 may be removed to leave the surface insulating layer 520 on the four surfaces in the Y direction and the Z direction. In addition, the surface insulating layer 520 may be made of parylene or various insulating materials such as a silicon oxide layer (SiO2), a silicon nitride layer (Si3N4), and a silicon oxynitride layer (SiON). When the surface insulating layer 520 is formed of the above materials, the surface insulating layer 520 may be formed by various methods (such as chemical vapor deposition (CVD) or physical vapor deposition (PVD)).The surface insulating layer 520 may have a thickness equal to or different from that of the external electrode 400, for example, a thickness of approximately 3 μm to approximately 30 μm.

[0071] 7. Coupling layer

[0072] A coupling layer 600 may be formed between the body 100 and the extended portion of the external electrode 400. That is, the external electrode 400 may extend in the Y direction and the Z direction (except for the two side surfaces of the body 100 in the X direction), and a coupling layer 600 may be formed between the body 100 and the extended portion of the external electrode 400. The coupling layer 600 may be formed such that the external electrode 400 is firmly formed on the four surfaces in the Y direction and the Z direction through a plating process. That is, since the surface insulating layer 520 is formed on the region where the external electrode 400 extends (i.e., the bent portion), the resistance of this region is greater than the resistance of the side surface of the body 100, and thus plating growth cannot be properly performed on this region. Therefore, the region of the external electrode 400 formed on the surface insulating layer 520 may have a smaller coupling force than the region of the external electrode 400 in contact with the body 100. Therefore, the coupling layer 600 is formed to increase the coupling force and tensile strength so that plating growth can be properly performed even on the surface insulating layer 520. When the coupling layer 600 is formed on the surface insulating layer 520 of the bent portion and then the extended region of the external electrode 400 is formed, the coupling force of the external electrode 400 can be further improved compared to when the extended portion of the external electrode 400 is formed on the surface insulating layer 520. The coupling layer 600 is formed on the surface insulating layer 520 and then remains only on the bent portion through a polishing process for exposing the coil pattern 300. That is, the surface insulating layer 520 is formed on the entire top surface of the body 100, the coupling layer 600 is formed on all of the two side surfaces of the body 100 and on a part of the front surface, rear surface, top surface, and bottom surface of the body 100, and then the two side surfaces of the body 100 are polished to expose the coil pattern 300. As a result, the coupling layer 600 remains on the bent portion. The coupling layer 600 can be formed by various methods (e.g., CVD, PVD, and plating). In addition, the coupling layer 600 can be formed of a metal (e.g., gold (Au), palladium (Pd), copper (Cu), and nickel (Ni) or an alloy of two or more of the above metals).

[0073] The coupling layer 600 can be formed by copper plating. Therefore, at least a part of the coil pattern 300, the external electrode 400, and the coupling layer 600 can be formed of the same material and through the same process. The coupling layer 600 may have a thickness smaller than the thickness of each of the surface insulating layer 520 and the external electrode 400. For example, the coupling layer 600 may have a thickness smaller than the thickness of the first layers 411, 421 of the external electrode 400.

[0074] 8. Top cover insulation layer

[0075] Such as Figure 10As shown in [Figure 0], a top cover insulating layer 530 may be formed on the top surface of the body 100 provided with the external electrode 400. That is, the top cover insulating layer 530 may be formed on the top surface of the body 100 (which is opposite to the bottom surface of the body 100 mounted on a printed circuit board (PCB)), for example, on the top side surface in the Z direction. The top cover insulating layer 530 may be formed to prevent a short circuit between the external electrode 400 extending from the top surface of the body 100 and a shield can, or a short circuit between the power inductor and the circuit components located above the power inductor. That is, while the external electrode 400 formed on the bottom surface of the body 100 is disposed adjacent to a power management integrated circuit (PMIC), the power inductor is mounted on the printed circuit board, where the PMIC has a thickness of approximately 1 millimeter, and the power inductor also has the same thickness. The PMIC may generate high-frequency noise that affects the surrounding circuits or components. Therefore, the PMIC and the power inductor may be covered by a shield can made of a metal material (e.g., stainless steel material). However, the power inductor may be short-circuited with the shield can because an external electrode is also provided above the power inductor. Therefore, when the top cover insulating layer 530 is formed on the top surface of the body 100, a short circuit between the power inductor and the external conductive material can be prevented. The top cover insulating layer 530 may be made of an insulating material (e.g., at least one selected from the group consisting of epoxy resin, polyimide, and liquid crystal polymer (LCP)). Additionally, the top cover insulating layer 530 may be made of a thermosetting resin. For example, the thermosetting resin may include at least one selected from the group consisting of novolac epoxy resin, phenoxy type epoxy resin, BPA type epoxy resin, BPF type epoxy resin, hydrogenated BPA epoxy resin, dimer acid modified epoxy resin, urethane modified epoxy resin, rubber modified epoxy resin, and DCPD type epoxy resin. That is, the top cover insulating layer 530 may be made of the insulating material 120 of the body 100 or the material used to form the surface insulating layer 520. The top cover insulating layer 530 may be formed by immersing the top surface of the body 100 in a polymer, a thermosetting resin, etc. Therefore, the top cover insulating layer 530 may be formed not only on the top surface of the body 100 but also on a part of the two side surfaces of the body 100 in the X direction and a part of the front surface and the rear surface of the body 100 in the Y direction. Additionally, the top cover insulating layer 530 may be made of parylene or various insulating materials such as a silicon oxide layer (SiO2), a silicon nitride layer (Si3N4), and a silicon oxynitride layer (SiON). When the top cover insulating layer 530 is formed of the above materials, the surface insulating layer 520 may be formed by various methods (e.g., CVD or PVD).When the top cover insulating layer 530 is formed by CVD or PVD, the top cover insulating layer 530 may be formed only on the top surface of the main body 100. The top cover insulating layer 530 may have a thickness for preventing a short circuit between the external electrode 400 of the main body 100 and the shielding case, for example, a thickness of approximately 10 micrometers to approximately 100 micrometers. Here, the top cover insulating layer 530 may have a thickness equal to or different from that of the external electrode 400 and equal to or different from that of the surface insulating layer 520. For example, the top cover insulating layer 530 may have a thickness greater than the thickness of each of the external electrode 400 and the surface insulating layer 520. As another alternative, the top cover insulating layer 530 may have a thickness equal to the thickness of each of the external electrode 400 and the surface insulating layer 520. Additionally, the top cover insulating layer 530 may be formed on the top surface of the main body with a uniform thickness to maintain a stepped portion between the external electrode 400 and the main body 100 or may have a thickness greater than the thickness on the top surface of the external electrode 400 on the top surface of the main body 100 to remove the stepped portion between the external electrode 400 and the main body 100 so that the surface is flat. As another alternative, the top cover insulating layer 530 may be separately formed with a predetermined thickness and then bonded to the main body 100 using an adhesive or the like.

[0076] As described above, the power inductor according to an exemplary embodiment can improve the coupling force between the body 100 and the external electrode 400 by forming at least a part of the thickness of the external electrode 400 with the same material and in the same method as the coil pattern 300. That is, when the coil pattern 300 and the external electrode 400 are formed by copper plating, the coupling force between the coil pattern 300 and the external electrode 400 can be improved. Therefore, the tensile strength can be further improved, and thus the body can be prevented from being separated from the electronic device in which the power inductor according to the exemplary embodiment is mounted. In addition, a coupling layer 600 can be formed between the surface insulating layer 520 and the external electrode 400 extending from the side surface of the body 100 (i.e., the external electrode on the bent portion). When the coupling layer 600 is formed, since the plating growth is properly performed on the extending region of the external electrode 400, the coupling force can be improved, and thus the tensile strength can also be improved. When the top cover insulating layer 550 is formed to prevent the external electrode 400 on the top surface of the body 100 from being exposed, the contact between the external electrode 400 and the shielding case can be prevented, and thus the short circuit between the external electrode 400 and the shielding case can be prevented. In addition, since the body 100 includes the heat conductive filler 130 in addition to the metal powder 110 and the insulating material 120, the heat of the body 100 caused by the heating of the metal powder 110 can be discharged to the outside to prevent the temperature of the body 100 from rising, and thus the limitations such as the reduction of inductance can be prevented. In addition, since the inner insulating layer 510 is formed between the coil pattern 310 and the coil pattern 320 and the body 100 using parylene, the inner insulating layer 510 can be formed with a small and uniform thickness on the side surfaces and the top surface of the coil pattern 310 and the coil pattern 320 and has improved insulating characteristics.

[0077] Manufacturing method

[0078] Figures 11 to 17 are cross-sectional views for sequentially illustrating a method of manufacturing a power inductor according to an exemplary embodiment.

[0079] Refer to Figure 11, coil patterns 310 and 320 having a predetermined shape are formed on at least one surface (preferably, one surface and the other surface of the base material 200) of the base material 200. The base material 200 can be made of a CCL or a metal magnetic material (preferably, a metal magnetic material that can increase the effective magnetic permeability and is easy to achieve capacitance). For example, the base material 200 can be manufactured by bonding copper foils to one surface and the other surface of a metal plate made of a metal alloy containing iron and having a predetermined thickness. Here, for example, a perforation 220 is formed in the central portion of the base material 200, and via holes 210 are formed in a predetermined region of the base material 200. Additionally, in addition to the perforation 220, the base material 200 can have a shape in which an outer region is removed. For example, the perforation 220 is formed in the central portion of the base material 200 having a rectangular plate shape with a predetermined thickness, the via holes 210 are formed in a predetermined region of the base material 200, and at least a part of the outside of the base material is removed. Here, the removed part of the base material 200 can be the outer part of the coil patterns 310 and 320 having a spiral shape. Additionally, the coil patterns 310 and 320 can be formed (e.g., in a circular spiral shape from the central portion) on a predetermined region of the base material 200. Here, the coil pattern 310 can be formed on one surface of the base material 200, and then a via hole passing through a predetermined region of the base material 200 and filled with a conductive material can be formed, and the coil pattern 320 can be formed on the other surface of the base material 200. The via holes 210 can be formed such that a through-hole is formed in the thickness direction of the base material 200 using a laser or the like, and then a conductive paste is filled into the through-hole. Additionally, the coil pattern 310 can be formed by, for example, a plating process. For this purpose, a photosensitive pattern having a predetermined shape can be formed on one surface of the base material 200, and a plating process can be performed using the copper foil on the base material 200 as a seed to grow a coupling layer from the exposed surface of the base material 200. Then, the photosensitive film can be removed to form the coil pattern 310. Additionally, the coil pattern 320 can be formed on the other surface of the base material 200 by the same method as the coil pattern 310. The coil patterns 310 and 320 can be formed to have a multilayer structure. When the coil patterns 310 and 320 are formed to have a multilayer structure, an insulating layer can be formed between the lower layer and the upper layer. Then, a second via hole (not shown) can be formed in the insulating layer to connect the multilayer coil patterns to each other. As described above, the coil patterns 310 and 320 can be formed on one surface and the other surface of the base material 200, and then, an inner insulating layer 510 can be formed to cover the coil patterns 310 and 320. The inner insulating layer 500 can be formed by coating an insulating polymer material (e.g., parylene).Preferably, by applying parylene, an inner insulating layer 510 can be formed not only on the top and side surfaces of the coil patterns 310 and 320 but also on the top and side surfaces of the base material 200. Here, the inner insulating layer 510 can be formed on the top and side surfaces of the coil patterns 310 and 320 and on the top and side surfaces of the base material 200 with the same thickness. That is, when the base material 200 having the coil patterns 310 and 320 formed thereon is prepared in a deposition chamber and then parylene is vaporized and supplied into a vacuum chamber, parylene can be deposited on the coil patterns 310 and 320 and the base material 200. For example, parylene can be initially heated in a vaporizer and vaporized into a dimer state, and then secondarily heated and thermally decomposed into a monomer state. When parylene is cooled using a cold trap and a mechanical vacuum pump connected to the deposition chamber, parylene can be converted from the monomer state to the polymer state and deposited on the coil patterns 310 and 320. Here, the initial heating process for vaporizing parylene into the dimer state is performed at a temperature of approximately 100°C to approximately 200°C and a pressure of approximately 1.0 Torr, and the secondary heating process for thermally decomposing the vaporized parylene into the monomer state is performed at a temperature of approximately 400°C to approximately 500°C and a pressure of approximately 0.5 Torr or greater than 0.5 Torr. Additionally, the deposition chamber can maintain a room temperature of approximately 25°C and a pressure of approximately 0.1 Torr to deposit parylene while converting the monomer state to the polymer state. Since parylene is applied to the coil patterns 310 and 320, the inner insulating layer 510 can be applied along the stepped portions between the coil patterns 310 and 320 and the base material 200, and thus, the inner insulating layer 510 can have a uniform thickness. As an alternative, the inner insulating layer 510 can be formed by closely attaching a sheet containing at least one selected from the group consisting of epoxy resin, polyimide, and liquid crystal polymer to the coil patterns 310 and 320.

[0080] Refer to Figure 12, a plurality of sheets (100a to 100h) made of a material including metal powder 110, polymer 120, and thermal conductive filler 130 are prepared. Here, the metal powder 110 may use a metal material containing iron (Fe), and the insulating material 120 may use epoxy resin and polyimide capable of insulating the metal powders 110 from each other. The thermal conductive filler may use MgO, AlN, and carbon-based materials capable of discharging the heat of the metal powder 110 to the outside. In addition, the surface of the metal powder 110 may be coated with a magnetic material, such as a metal oxide magnetic material or an insulating material (e.g., parylene). Here, based on 100% by weight of the metal powder 110, the insulating material 120 may be included in an amount of 2.0% to 5.0% by weight, and based on 100% by weight of the metal powder 110, the thermal conductive filler 130 may be included in an amount of 0.5% to 3% by weight. The plurality of sheets 100a to 100h are respectively disposed above and below a substrate material 200 on which a coil pattern 310 and a coil pattern 320 are formed. The contents of the thermal conductive filler of the plurality of sheets 100a to 100h may be different. For example, the content of the thermal conductive filler may gradually increase upward and downward from one surface and the other surface of the substrate material 200. That is, the content of the thermal conductive filler in each of the sheets 100b and 100f disposed above and below the sheets 100a and 100e in contact with the substrate material 200 may be greater than the content of the thermal conductive filler in each of the sheets 100a and 100e, and the content of the thermal conductive filler in each of the sheets 100c and 100g disposed above and below the sheets 100b and 100f may be greater than the content of the thermal conductive filler in each of the sheets 100b and 100f. Since the content of the thermal conductive filler gradually increases in the direction away from the substrate material 200, the heat transfer efficiency can be further improved. A first magnetic layer (not shown) and a second magnetic layer (not shown) may be respectively disposed above and below the uppermost sheet 100d and the lowermost sheet 100h. The first magnetic layer and the second magnetic layer may be made of a material having a higher magnetic permeability than the magnetic permeability of the sheets 100a to 100h. For example, the first magnetic layer and the second magnetic layer may be made of magnetic powder and epoxy resin to have a higher magnetic permeability than the magnetic permeability of the sheets 100a to 100h. In addition, the first magnetic layer and the second magnetic layer may further include a thermal conductive filler.

[0081] Refer to Figure 13 , the body 100 is formed such that a plurality of sheets 100a to 100h disposed between each other with the substrate material 200 can be laminated and pressed and then molded. Therefore, the perforations 220 and the removed portions of the substrate material 200 can be filled with the body 100. In addition, the body 100 and the substrate material 200 are cut into unit elements. The body 100 cut into unit elements can be molded or cured.

[0082] Refer toFigure 14 , a surface insulating layer 520 is formed on the surface of the body 100. The surface insulating layer 520 can be formed by various methods including printing, dipping, and spraying. In addition, the surface insulating layer 520 can be formed using an insulating material (e.g., silicon, epoxy resin, organic coating solution, and glass frit) and can have a thickness of approximately 5 microns to approximately 40 microns. Here, the edge of the body can be polished before forming the surface insulating layer 520. That is, the edge can be chamfered by a polishing process to prevent the body 100 from cracking. Here, the edge of the body 100 can be formed to be inclined or rounded to have a predetermined angle instead of a right angle. Since the edge of the body 100 is inclined, the external electrode 400 can be formed with a uniform thickness. That is, when the edge of the body 100 has a right angle, the external electrode 400 can be formed on the edge with a thickness smaller than the thickness of the surface, and thus limitations may occur where the external electrode 400 is cut or the resistance increases. Therefore, since the edge is formed to be inclined, such limitations can be prevented.

[0083] Refer to Figure 15, a coupling layer 600 is formed on a predetermined area of the body 100 having a surface insulating layer 520 formed thereon. The coupling layer 600 may be formed on an area where the external electrode 400 will be formed thereon. For example, when the external electrodes 400 are formed on two side surfaces of the body 100 that are opposite to each other in the X direction, the coupling layer 600 may be formed on the two surfaces of the body 100 in the X direction and on the surfaces adjacent to the two surfaces in the Y direction and the Z direction. The coupling layer 600 may be formed by various methods (e.g., PVD, CVD, plating, dipping, and spraying). Additionally, the coupling layer 600 may be made of a metal (including gold (Au), palladium (Pd), copper (Cu), and nickel (Ni) and an alloy of two or more of the above metals). That is, the coupling layer 600 may be made of a metal or a metal alloy in one layer or two or more layers. For example, the coupling layer 600 may be formed of at least one of a gold layer and a palladium layer by PVD or CVD. As another example, the coupling layer 600 may be formed by plating, dipping, or spraying using a solution in which at least one of nickel and copper is melted or a solution in which at least one of gold and palladium is melted. Since a brightener and a carrier containing polyethylene glycol (PEG) are used for the solution in which metal particles are melted, the uniformity, electrodeposition characteristics, and gloss characteristics can be enhanced. The coupling layer 600 may be formed using the same material and the same method as the external electrode 400. That is, since the coupling layer 600 and the external electrode 400 are formed using the same material and the same method, the coupling layer 600 and the external electrode 400 may have the same properties, and thus the coupling force between the coupling layer 600 and the external electrode 400 can be improved. For example, the coupling layer 600 may be formed by a copper plating process. As an alternative, in order to form the coupling layer 600 only on partial areas in the Y direction and the Z direction, the coupling layer 600 may be formed, and then an etching process for removing partial areas of the coupling layer 600 may be performed or a predetermined mask may be formed, and then the coupling layer 600 may be formed and the mask may be removed.

[0084] Referring to Figure 16 , the coupling layer 600 and the surface insulating layer 520 provided on a partial surface of the body are removed. That is, the coupling layer 600 and the surface insulating layer 520 on the area where the external electrode 400 will be formed thereon are removed so that the external electrode is connected to the coil pattern 300. For example, the coupling layer 600 and the surface insulating layer 520 located on two side surfaces of the body 100 that face each other in the X direction are removed. Here, the coupling layer 600 and the surface insulating layer 520 are removed to expose the coil pattern 300 to the side surface of the body 100. For example, a polishing process may be used to expose the coil pattern 300. Thus, the coupling layer 600 may remain on partial areas of the four surfaces of the body 100 in the Y direction and the Z direction.

[0085] Referring to Figure 17 , external electrodes 400 may be formed on two end portions of the body 100 of the unit element such that the external electrodes 400 are electrically connected to the lead-out portions of the coil patterns 310 and 320. The external electrodes 400 may extend from the two side surfaces of the body exposed by the coil pattern 300 to the surfaces of the body 100 adjacent to the two side surfaces. That is, the external electrodes 400 may be formed on the two side surfaces of the body 100 and on the coupling layer 600 of the body 100 adjacent to the two side surfaces. Here, at least a part of the external electrodes 400 may be formed using the same material and the same method as the coil pattern 300. That is, the first layers 411, 421 may be formed by various methods such as electroless plating and electroplating, and the second layers 412, 422 may be formed of at least one layer by a plating process using nickel, tin, etc. Here, the external electrodes 400 may use the coil pattern 300 exposed to the outside of the body 100 as a seed. Since the coupling layer 600 is formed on the body 100 and the extending regions (i.e., the bent portions) of the external electrodes 400, the external electrodes 400 can be properly formed on the bent portions and thus the coupling force of the bent portions can be improved. The first layers 411, 421 may have a thickness of approximately 5 μm to approximately 40 μm, and the second layers 412, 422 may have a thickness of approximately 1 μm to approximately 20 μm. Additionally, when the second layers 412, 422 have two layers (e.g., a nickel plating layer and a tin plating layer), the nickel plating layer may have a thickness of approximately 1 μm to approximately 10 μm, and the tin plating layer may have a thickness of approximately 1 μm to approximately 10 μm. That is, the nickel plating layer may have the same thickness as the tin plating layer. Here, the plating solution for forming the first layers 411, 421 may use a plating solution in which approximately 5% sulfuric acid (H2SO4) and approximately 20% copper sulfate (CuSO4) are mixed or a plating solution in which approximately 25% acid agent and approximately 3.5% copper are mixed. When at least a part of the external electrodes 400 is formed by copper plating, the coupling force of the external electrodes 400 may become stronger. Here, the coupling force between the coil pattern 300 and the external electrodes 400 may be greater than the coupling force between the body 100 and the external electrodes 400. The top cover insulating layer may be formed so as not to expose the external electrodes 400 extending to the top surface of the body 100.

[0086] Experimental example

[0087] According to an exemplary embodiment, since at least a part of the external electrode 400 is formed by the same method as the coil pattern 300 (i.e., copper plating), the coupling force between the external electrode 400, the coil pattern 300, and the body 100 can be increased. Additionally, since the coupling layer 600 is formed on the extended region of the external electrode 400 (i.e., below the external electrode 400 of the bent portion), the coupling force between the external electrode 400 and the body 100 can be increased. A comparison was made in terms of tensile strength between an exemplary embodiment in which the coupling layer 600 is formed on the bent portion and the external electrode is formed by copper plating and a prior art example in which the external electrode is formed by applying epoxy resin.

[0088] First, an external electrode was formed to measure the tensile strength, and then a wire was welded to the external electrode. The tensile strength was measured by pulling the welded wire. That is, the tensile strength was measured when the body 100 was torn or the external electrode 400 was separated from the body 100 by pulling the wire. Here, the external electrode was formed by applying epoxy resin in the prior art example, and the external electrode was formed by plating in the exemplary embodiment. Here, the coupling layer was not formed in the prior art example, and the coupling layer was formed in the exemplary embodiment. That is, although the external electrode was formed by applying conductive epoxy resin in a state where a surface insulating layer was formed in the prior art example, the coupling layer was formed on a partial region of the surface insulating layer and then the external electrode was formed by a plating process in the exemplary embodiment. Additionally, in the prior art example and the exemplary embodiment, the shapes of the body, the base material, and the coil pattern were the same. Additionally, a plurality of power inductors were manufactured according to the prior art example and the exemplary embodiment, and then the tensile strength of each of the plurality of power inductors was measured. After that, the average value of the measured tensile strengths was calculated.

[0089] Figure 18 is a graph showing a state in which the tensile strengths according to the prior art example and the exemplary embodiment are compared. Here, the tensile strength represents the force when the external electrode is separated from the body by increasing the force of pulling the wire. As Figure 18As shown, in the prior art example, a tensile strength of approximately 2.2 kgf to approximately 2.35 kgf was measured, and an average value of approximately 2.28 kgf was calculated. However, in the exemplary embodiment, a tensile strength of approximately 3.0 kgf to approximately 3.1 kgf was measured, and an average value of approximately 3.05 kgf was calculated. For reference, the ranges shown in the drawings refer to the measurement ranges, and the points between the ranges refer to the average values. Therefore, the tensile strength of the exemplary embodiment is approximately 30% to approximately 40% greater than the tensile strength of the comparative example. Therefore, in the exemplary embodiment, the coupling force between the external electrode and the body or the coil pattern can be improved, and thus there is no limitation in which the body separates when the body is mounted to the electronic device.

[0090] In the exemplary embodiment, when tension is continuously applied, the body may break. That is, as Figure 19 shown, when tension is continuously applied, the body may break. That is, the external electrode separates from the body according to the tensile strength in the prior art. However, in the exemplary embodiment, the body may break when tension is continuously applied because the coupling force between the coil pattern and the external electrode is greater than the coupling force between the body and the external electrode. That is, in the exemplary embodiment, since the coupling force between the coil pattern and the external electrode is extremely large, even though the body breaks, the body and the external electrode may still not separate from each other. Additionally, the body and the external electrode are strongly coupled to the bent portion through the coupling portion, and the external electrode of the bent portion does not separate.

[0091] Other embodiments

[0092] Hereinafter, other exemplary embodiments will be described. In another exemplary embodiment, descriptions that are repetitive of the detailed descriptions in the above exemplary embodiment will be omitted. Unless otherwise described, the detailed configuration of another exemplary embodiment is the same as the detailed configuration of the above exemplary embodiment. For example, in other exemplary embodiments, the external electrode 400 includes a first layer formed by copper plating and a second layer formed by nickel plating or tin plating. Additionally, the surface insulating layer 520 is formed on four surfaces except for the two side surfaces of the upper surface of the body 100 where the external electrode 400 is formed in a contact manner, and the coupling layer 600 is formed between the extended region of the external electrode 400 and the surface insulating layer 520.

[0093] According to a second exemplary embodiment, the power inductor may further include at least one magnetic layer (not shown) disposed in the body 100. The magnetic layer may be disposed on at least one of the top surface and the bottom surface. Additionally, at least one magnetic layer may be disposed in the body 100 between the base material 200 and the top surface or the bottom surface of the body. Here, the magnetic layer may be configured to increase the magnetic permeability of the body 100 and be made of a material having a greater magnetic permeability than the body 100. For example, the body 100 may have a magnetic permeability of approximately 20, and the magnetic layer may have a magnetic permeability of approximately 40 to approximately 1000. The magnetic layer may be manufactured using, for example, magnetic powder and an insulating material. That is, the magnetic layer may be made of a material having a greater magnetic property than the magnetic material of the body 100 to have a high magnetic permeability, or may have a further greater content of magnetic material. For example, in the magnetic layer, based on approximately 100% by weight of the metal powder, an insulating material may be added in an amount of approximately 1% to approximately 2% by weight. That is, the amount of metal powder included in the magnetic layer may be greater than the amount of metal powder of the body 100. The magnetic layer may further include a heat-conductive filler (not shown in the figure) in addition to the metal powder and the insulating material. Based on approximately 100% by weight of the metal powder, the heat-conductive filler may be included in an amount of approximately 0.5% to approximately 3% by weight. The materials used as the metal powder and the heat-conductive filler of the magnetic layer may be selected from the materials suggested in the description of the above exemplary embodiments. The magnetic layer may be manufactured in a sheet type and disposed on each of the upper portion and the lower portion of the body in which a plurality of sheets are laminated. Additionally, the body 100 may be formed by printing a paste made of a material including the metal powder 110 and the polymer 120 or further including the heat-conductive filler 130 with a predetermined thickness, or filling the paste into a frame and pressing the paste, and then the magnetic layers 710, 720 may be formed on each of the upper portion and the lower portion of the body 100. As another alternative, the magnetic layer may be formed using a paste, that is, the magnetic layer may be formed by applying a magnetic material to the upper portion and the lower portion of the body 100.

[0094] As described above, the power inductor according to another exemplary embodiment may include at least one magnetic layer in the body 100 to enhance the magnetism rate of the power inductor.

[0095] According to a third exemplary embodiment, at least two base materials 200 may be provided in the body 100, and coil patterns 300 may be formed on one surface of each of the at least two base materials 200. In addition, external electrodes 400 are formed outside the body 100 such that the external electrodes 400 are connected to the coil patterns 300 formed on each of the different base materials 200, and connection electrodes (not shown) may be formed outside the body to connect the coil patterns 300 formed on each of the different base materials 200. For example, a first external electrode may be formed to be connected to a first coil pattern formed on a first base material, a second external electrode may be formed to be connected to a third coil pattern formed on a second base material, and the connection electrode may be formed to be connected to a second coil pattern and a fourth coil pattern formed on the first base material and the second base material, respectively. Here, the connection electrode may be formed on at least one surface of the body 100 where the external electrode 400 is not formed on the upper surface in the Y direction, for example. In addition, the connection electrode may be formed using the same material and the same process as the external electrode 400.

[0096] As described above, the capacitance of the power inductor according to the third exemplary embodiment may be increased such that at least two base materials 200 (each of which has a coil pattern 300 formed on at least one surface) are spaced apart from each other in the body 100, and when the coil patterns 300 formed on each of the different base materials 200 are connected by the connection electrodes outside the body 100, a plurality of coil patterns are formed. That is, by using the connection electrodes outside the body 100, the coil patterns 300 formed on different base materials 200 may be connected in series to each other, and thus the capacitance of the power inductor in the same area may be increased.

[0097] According to a fourth exemplary embodiment, a power inductor may include: at least two base materials 200 vertically disposed in a body 100; coil patterns 300 formed on at least one surface of each of the at least two base materials 200; and external electrodes 400 disposed outside the body 100 and connected to the coil patterns 300 respectively formed on the at least two base materials 200. For example, the plurality of base materials 200 may be spaced apart from each other in a longitudinal direction perpendicular to the thickness direction of the body 100. That is, although the plurality of base materials 200 are arranged in the thickness direction (e.g., the vertical direction) of the body 100 according to another exemplary embodiment, the plurality of base materials 200 are arranged in a direction perpendicular to the thickness direction of the body 100 (e.g., the horizontal direction) according to still another exemplary embodiment. Additionally, the external electrodes 400 may be connected to each of the coil patterns 300 respectively formed on the plurality of base materials 200. For example, each of the first external electrode and the second external electrode opposite to each other is connected to the coil pattern formed on the first base material, each of the third external electrode and the fourth external electrode spaced apart from the first external electrode and the second external electrode is connected to the coil pattern formed on the second base material, and each of the fifth external electrode and the sixth external electrode spaced apart from the third external electrode and the fourth external electrode is connected to the coil pattern formed on the third base material. That is, the external electrodes 400 are connected to the coil patterns 300 respectively formed on the plurality of base materials 200.

[0098] As described above, the power inductor according to the fourth exemplary embodiment can achieve a plurality of inductors in one body 100. That is, since at least two base materials 200 are arranged in the horizontal direction and the coil patterns 300 respectively formed on the at least two base materials 200 are connected to different external electrodes 400, the plurality of inductors are arranged parallel to each other, and thus at least two power inductors are achieved in one body 100.

[0099] According to the fifth exemplary embodiment, at least two base materials 200 are stacked and spaced apart by a predetermined distance in the thickness direction (e.g., the vertical direction) of the body 100, and the coil patterns 300 formed on the base materials 200 are led out in different directions from each other and are respectively connected to the external electrodes 400. That is, although the plurality of base materials 200 are arranged in the horizontal direction according to another exemplary embodiment, the plurality of base materials 200 are arranged in the vertical direction according to still another exemplary embodiment. Therefore, according to still another exemplary embodiment, since at least two base materials 200 are arranged in the thickness direction of the body 100 and the coil patterns 300 respectively formed on the base materials 200 are connected through different external electrodes 400, the plurality of inductors are arranged in parallel with each other, and thus at least two power inductors are achieved in one body 100.

[0100] As described above, according to the third exemplary embodiment to the fifth exemplary embodiment, the plurality of base materials 200 (each of which has a coil pattern 300 formed on at least one surface) are stacked in the thickness direction (i.e., the vertical direction) of the body 100 or arranged in a direction perpendicular to the thickness direction (i.e., the horizontal direction). In addition, the coil patterns 300 respectively formed on the plurality of base materials 200 can be connected to the external electrodes 400 in series or in parallel. That is, the coil patterns 300 respectively formed on the plurality of base materials 200 can be connected in parallel to different external electrodes 400, and the coil patterns 300 respectively formed on the plurality of base materials 200 can be connected in series to the same external electrode 400. In the case of series connection, the coil patterns 300 respectively formed on the base materials 200 can be connected to the external electrodes through connection electrodes outside the body 100. Therefore, in the case of parallel connection, each of the plurality of base materials 200 requires two external electrodes 400, and in the case of series connection, two external electrodes 400 and at least one connection electrode are required regardless of the number of base materials 200. For example, when the coil patterns 300 formed on at least three base materials 200 are connected in parallel to the external electrodes 400, six external electrodes 400 are required, and when the coil patterns 300 formed on at least three base materials 200 are connected in series to the external electrodes 400, two external electrodes 400 and at least one connection electrode are required. In addition, in the case of parallel connection, a plurality of coils are provided in the body 100, and in the case of series connection, one coil is provided in the body 100.

[0101] According to an exemplary embodiment, a power inductor including at least one base material 200 having a coil pattern 300 formed thereon and disposed in a body 100 is described as an example. However, the exemplary embodiment can be applied to all chip components having external electrodes formed on the surface of the body. For example, the exemplary embodiment can be applied to components for forming external electrodes, such as chip components in which an inductor and a capacitor are formed and chip components in which an electrostatic discharge (ESD) protection unit (e.g., varistor or suppressor) is formed. That is, the exemplary embodiment can include: a body; a conductive layer disposed in the body; an external electrode disposed outside the body to connect to the conductive layer; a surface insulating layer formed on the remaining surfaces except for the surface connecting the conductive layer to the external electrode; and a coupling layer disposed between an extended area of the external electrode and the surface insulating layer. Here, the conductive layer can be the coil pattern described in the exemplary embodiment, a plurality of internal electrodes of the capacitor spaced apart from each other by a predetermined distance, and a discharge electrode in the varistor or suppressor. As an alternative, the external electrode can be formed outside the body in which all of these elements, such as the coil pattern, the internal electrode, and the discharge electrode, are formed.

[0102] In addition, the exemplary embodiment can be applied to an inductor including a wound coil formed in a body. That is, as Figures 20 to 23 shown, the exemplary embodiment can be applied to a wound inductor including an external electrode 400 located outside the body 100, in which a wound coil 300c is disposed between an upper body 100a and a lower body 100b in the body 100, and a metal magnetic powder and an epoxy resin are mixed in the body 100. Figures 20 to 22 are perspective views sequentially showing a manufacturing process to illustrate another exemplary embodiment applied to the wound inductor, and Figure 23 is a cross-sectional view.

[0103] As Figure 20As shown, a receiving portion in which the wound coil 300c is received is defined in the lower body 100b, and the upper body 100a is disposed above the lower body 100b to cover the receiving portion. A lead-out portion 300d may be defined in the outer surface of the lower body 100b, and the wound coil 300c is led out through the lead-out portion 300d. Here, although not shown, the wound coil 300c and the lead-out portion 300d may be coated with an inner insulating layer. When the upper body 100a covers the lower body 100b and then the lower body 100b is pressed, the body 100 may be filled in the space defined by the wound coil 300c. For example, by pressing the body 100, the upper body 100a may be formed to fill the inner space of the wound coil 300c and the space between the wound coils 300c.

[0104] As Figure 21 shown, the body 100 is polished and sized. That is, the body 100 is sized by polishing four surfaces or six surfaces of the body 100. Here, a part of the lead-out portion of the wound coil 300c may be polished, and thus the thickness of the lead-out portion may be reduced.

[0105] As Figure 22 shown, an external electrode 400 may be provided on the lead-out portion 300d. Here, the external electrode 400 may extend from the side surface to only the bottom surface of the body 100. That is, the external electrode 400 may have, for example, an "L"-shape. As another option, the external electrode 400 may extend to the adjacent four surfaces in addition to extending to the side surface. Here, a surface insulating layer 520 is formed on the regions where the external electrode 400 is not formed, that is, on the top surface and the bottom surface of the body 100 in the Z direction and on the front surface and the rear surface of the body 100. A coupling layer 600 is formed on the bottom surface of the body 100 in the Z direction, and then the external electrode 400 is formed on the side surface of the body 100 and the coupling layer 600. Here, the surface insulating layer 520 and the coupling layer 600 may be formed on the upper body 100a and the lower body 100b first before the wound coil 300c is embedded. That is, the surface insulating layer 520 is formed on the outer surface of the lower body 100b, and the coupling layer 600 is formed on a predetermined region of the lower body 100b. Then, the upper body 100a having the surface insulating layer 520 formed on its outer surface may be coupled to the lower body 100b. As another option, the upper body 100a and the lower body 100b may be coupled to each other, and then the surface insulating layer 520 and the coupling layer 600 may be formed and the external electrode 400 may be formed. Figure 23 is a cross-sectional view showing the wound inductor manufactured as described above.

[0106] In a power inductor according to an exemplary embodiment, a coupling layer 600 may not be formed on at least a part of the power inductor, and at least a part of the surface insulating layer 520 may be removed. For example, as Figure 24 shown, the surface insulating layer 520 may not be formed on the region to which the external electrode 400 extends. That is, the surface insulating layer 520 may be formed only on the surface of the body where the external electrode 400 is not formed on the upper surface. Therefore, the external electrode 400 and the extended region of the external electrode 400 may be in contact with the surface of the body 100. Additionally, as Figure 25 shown, the surface insulating layer 520 may not be formed on at least a part of the region to which the external electrode 400 extends. That is, although the surface insulating layer 520 is formed on a part of the region to which the external electrode 400 extends, the surface insulating layer 520 may not be formed on another part of the region. For example, the surface insulating layer 520 may not be formed on a part of the top surface of the body 100 to which the external electrode 400 extends, and may be formed on a part of the bottom surface of the body 100 including the region to which the external electrode 400 extends. Therefore, one part of the extended region of the external electrode 400 may be in contact with the surface insulating layer 520, and the other part may be in contact with the body 100. Here, the coupling layer 600 may be formed between the surface insulating layer 520 and the extended region of the external electrode 400. Additionally, as Figure 26 shown, the external electrode 400 may not extend to a partial region. That is, even in the case of a thin-film type power inductor, like the Figure 23 wound inductor, the external electrode 400 may not extend to the top surface of the body 100 but may extend only to the region including the bottom surface of the body 100. Here, the surface insulating layer 520 may be formed on the entire top surface of the body 100 where the external electrode 400 does not extend, and may be formed on the region where the external electrode 400 is not formed on the upper surface (including the bottom surface of the body 100 to which the external electrode 400 extends). That is, the surface insulating layer 520 may not be formed on the region where the external electrode 400 is formed on the upper surface. Therefore, the external electrode 400 may be in contact with the surface of the body 100. However, although not shown in the figure, the surface insulating layer 520 may also be formed on the part to which the external electrode 400 extends, and a coupling layer 600 may be formed between the surface insulating layer 520 and the part.

[0107] However, the present invention may be implemented in different forms and should not be considered limited to the embodiments described herein. Therefore, those skilled in the art will readily understand that various modifications and alterations can be made to the present invention without departing from the spirit and scope of the invention defined by the appended claims.

Claims

1. A power inductor, comprising: A body having a hexahedral shape and including magnetic layers provided on a top surface and a bottom surface, respectively; A coil pattern provided in the body; External electrodes provided on two side surfaces of the body and extending to the top surface, the bottom surface, a front surface, and a rear surface of the body adjacent to the two side surfaces; A surface insulating layer provided on the entire top surface, the bottom surface, the front surface, and the rear surface of the body except for the two side surfaces connecting the coil pattern to the external electrodes; And A coupling layer provided between the surface insulating layer and an extended area of the external electrode, and provided on the top surface, the bottom surface, the front surface, and the rear surface of the body.

2. The power inductor according to claim 1, wherein the coupling layer comprises a metal or a metal alloy.

3. The power inductor according to claim 1, wherein at least a portion of the external electrode comprises the same material as at least one of the coil pattern and the coupling layer.

4. The power inductor according to claim 1, wherein the external electrode includes a first layer and at least one second layer, the first layer being configured to contact the coil pattern and the coupling layer, and the at least one second layer being disposed on the first layer and made of a material different from that of the first layer.

5. A method of manufacturing a power inductor, the method comprising: Prepare a body having a hexahedral shape, in which a coil pattern is formed, and the body includes magnetic layers provided on a top surface and a bottom surface, respectively; Form a surface insulating layer on the entire surface of the body; Form a coupling layer on the surface insulating layer so as to extend to the two side surfaces of the body and the top surface, the bottom surface, the front surface, and the rear surface of the body adjacent to the two side surfaces; Remove a part of the coupling layer and a part of the surface insulating layer formed on the two side surfaces of the body to expose the coil pattern; And Form external electrodes extending from the two side surfaces of the body to the coupling layer so that the external electrodes are connected to the coil pattern.

6. The method according to claim 5, wherein at least a portion of the external electrode is formed using the same material as at least one of the coil pattern and the coupling layer.

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