Patent Publication Number: US-11657950-B2

Title: Magnetic composite sheet and coil component

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of priority to Korean Patent Application No. 10-2020-0008228 filed on Jan. 22, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a magnetic composite sheet and a coil component. 
     2. Description of Related Art 
     An inductor, one of a coil component, is a representative passive element utilized in an electronic device together with a resistor and a capacitor. 
     As for a thin film coil component, a type of coil component, a body is formed by forming a coil portion on at least one surface of a substrate followed by stacking a magnetic complex sheet containing a magnetic metal powder particle on the substrate. 
     In regard to the above, there may be a case in which a body is formed using a magnetic complete sheet containing two or more different magnetic metal powder particles having different diameters to improve characteristics of the coil component by improving a percentage of a magnetic body (magnetic metal powder particle) of the body. 
     As the diameter of the magnetic metal powder particle decreases, it becomes more difficult to form an insulating film on the surface of the magnetic metal powder particle, thereby decreasing insulation resistance of the body. 
     In addition, entire insulation resistance of the body may be reduced due to a reduced distance between the magnetic metal powder particles when a charging rate of the magnetic metal powder particle is improved to improve the magnetic body percentage of the body. 
     SUMMARY 
     An aspect of the present disclosure may provide a coil component and a magnetic composite sheet capable of easily reducing leakage current among coil components containing least three or more magnetic metal powder particle having different diameters. 
     According to an aspect of the present disclosure, a coil component includes a body and a coil portion embedded in the body, wherein the body comprises a first magnetic metal powder particle comprising a core comprising a compound represented by Formula 1 below, and an oxide film comprising at least one of silicon (Si) or chromium (Cr) and formed on a surface of the core, a second magnetic metal powder particle having a larger diameter than the first magnetic metal powder particle, and a third magnetic metal powder particle having a larger diameter than the second magnetic metal powder particle:
 
Fe a Si b Cr c   [Formula 1]
 
     where 3 atom %≤b≤6 atom %, 2.65 atom %≤c≤3.65 atom %, and a+b+C=100. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a schematic diagram illustrating a coil component according to an exemplary embodiment of the present disclosure; 
         FIG.  2    is a cross-sectional view taken along line I-I′ of  FIG.  1   ; 
         FIG.  3    is a cross-sectional view taken along line II-II′ of  FIG.  1   ; 
         FIG.  4    is an enlarged view of “A” of  FIG.  2   ; 
         FIG.  5    is an enlarged view of “B” of  FIG.  2   ; 
         FIG.  6    is a modified example of “B” of  FIG.  2   ′; 
         FIG.  7    is a schematic diagram illustrating a coil component according to another exemplary embodiment; 
         FIG.  8    is a diagram illustrating the coil component of  FIG.  7    viewed from a lower portion; 
         FIG.  9    is a schematic diagram illustrating a coil component according to Experimental Example 3 and corresponding to the cross-section taken along line I-I′ of  FIG.  1   ; 
         FIG.  10    is a cross-sectional view taken along line III-III′ of  FIG.  7   ; 
         FIG.  11    is a schematic diagram illustrating a magnetic composite sheet according to an exemplary embodiment; and 
         FIG.  12    an enlarged view of “C” of  FIG.  11   . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinbelow, terms referring to the elements of the present disclosure are named in consideration of the functions of the respective elements, and thus should not be understood as limiting the technical elements of the present disclosure. As used herein, singular forms may include plural forms as well unless the context explicitly indicates otherwise. Further, as used herein, the terms “include”, “have”, and their conjugates denote a certain feature, numeral, step, operation, element, component, or a combination thereof, and should not be construed to exclude the existence of or a possibility of addition of one or more other features, numerals, steps, operations, elements, components, or combinations thereof. In addition, it will be the term “on” does not necessarily mean that any element is positioned on an upper side based on a gravity direction, but means that any element is positioned above or below a target portion. 
     Throughout the specification, it will be understood that when an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it can be understood as being “directly connected” or “directly coupled” to the other element or layer or intervening elements or layers may be present. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” specify the presence of elements, but do not preclude the presence or addition of one or more other elements. 
     The size and thickness of each component illustrated in the drawings are represented for convenience of explanation, and the present disclosure is not necessarily limited thereto. 
     In the drawings, the expression “W direction” may refer to “first direction” or “width direction,” and the expression “L direction” may refer to “second direction” or “length direction” while the expression “T direction” may refer to “third direction” or “thickness direction”. 
     A value used to describe a parameter such as a 1-D dimension of an element including, but not limited to, “length,” “width,” “thickness,” “diameter,” “distance,” “gap,” and/or “size,” a 2-D dimension of an element including, but not limited to, “area” and/or “size,” a 3-D dimension of an element including, but not limited to, “volume” and/or “size”, and a property of an element including, not limited to, “roughness,” “density,” “weight,” “weight ratio,” and/or “molar ratio” may be obtained by the method(s) and/or the tool(s) described in the present disclosure. The present disclosure, however, is not limited thereto. Other methods and/or tools appreciated by one of ordinary skill in the art, even if not described in the present disclosure, may also be used. 
     In electronic devices, various types of electronic components may be used, and various types of coil components may be appropriately used between the electronic components to remove noise, or for other purposes. 
     In other words, a coil component in electronic devices may be used as a power inductor, a high frequency inductor, a general bead, a high frequency (GHz) bead, a common mode filter, or the like. Hereinafter, exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The same or corresponding components were given the same reference numerals and will not explained further. 
       FIG.  1    is a schematic diagram illustrating a coil component according to an exemplary embodiment of the present disclosure, and  FIG.  2    is a cross-sectional view taken along line I-I′ of  FIG.  1   .  FIG.  3    is a cross-sectional view taken along line II-II′ of  FIG.  1   , while  FIG.  4    is an enlarged view of “A” of  FIG.  2   , and  FIG.  5    is an enlarged view of “B” of  FIG.  2   .  FIG.  6    is a modified example of “B” of  FIG.  2   . 
     Based on  FIGS.  1  to  6   , a coil component  1000  according to an exemplary embodiment includes a body  100 , an insulating substrate  200 , a coil portion  300  and external electrodes  400  and  500 , and may further include an insulating film  600 . 
     The body  100  may form an exterior of the coil component  1000 , and may bury the coil portion  300  in the body  100 . 
     The body  100  may have a hexahedral shape. 
     Based on  FIGS.  1  to  3   , the body  100  may include a first surface  101  and a second surface  102  opposing each other in a length direction L, a third surface  103  and a fourth surface  104  opposing each other in a width direction W, and a fifth surface  105  and a sixth surface  106  opposing each other in a thickness direction T. The first to fourth surfaces  101  to  104  of the body  100  may be walls of the body  100  connecting the fifth surface  105  and the sixth surface  106  of the body  100 . In the description below, the expression “both end surfaces of the body” may refer to the first surface  101  and the second surface  102  of the body  100 , and the expression “both side surfaces of the body” may refer to the third surface  103  and the fourth surface  104  of the body  100  while the expression “one surface of the body” may refer to the sixth surface  106  of the body  100  and the expression “the other surface of the body” may refer to the fifth surface  105  of the body. Further, the expression “upper and lower surfaces of the body may refer to the fifth and sixth surfaces  105  and  106  of the body  100  defined with respect to the direction of  FIGS.  1  to  3   . 
     The body  100  may be formed such that the coil component  1000  according to an exemplary embodiment including external electrodes  400  and  500  has a thickness of 0.85 mm or less. As an example, the body  100  may be configured such that the coil component  1000  in which the external electrodes  400  and  500  are formed may have a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.85 mm. Alternately, the body may be configured such that the coil component  1000  in which the external electrodes  400  and  500  are formed may have a length of 2.0 mm, a width of 1.6 mm, and a thickness of 0.55 mm, or a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.55 mm. Alternately, the body may be configured such that the coil component  1000  in which the external electrodes  400  and  500  are formed may have a length of 1.2 mm, a width of 1.0 mm, and a thickness of 0.55 mm, but is not limited thereto. The sizes of the coil component  1000  indicated above are merely examples, and thus, the present disclosure is not limited thereto. An overall thickness of the component of 0.85 mm or less falls within the scope of the present disclosure. The thickness can be measured by a method other than the micrometer method, which is appreciated by the one skilled in the art. In the previously described examples, each value of the widths and thicknesses are not applied with process errors. When compared with the above numerical values, the case having a difference which can be recognized as a process error falls within the scope of the present disclosure. 
     A thickness of the coil component may be obtained by measuring the thickness of the component using a micrometer. The thickness of the component may refer an arithmetic mean of thicknesses of a plurality of components (for example, 30). Each of the thickness of the components is obtained by the above-mentioned micrometer method. A length of the coil component and a width of the coil component could be obtained by the above-mentioned micrometer method, and by the above-mentioned arithmetic mean method. 
     The body  100  may contain magnetic metal powder particles  11  to  13  and an insulating resin R. Specifically, the body  100  may be formed by layering one or more magnetic composite sheets containing the magnetic metal powder particles  11  to  13  dispersed in the resin R followed by curing the magnetic composite sheet. The magnetic metal powder particles  11  to  13  contain a first magnetic metal powder particle  11 , a second magnetic metal powder particle  12  having a larger diameter than the first magnetic metal powder particle  11 , and a third magnetic metal powder particle  13  having a larger diameter than the second magnetic metal powder particle  12 . In the present exemplary embodiment, as the body  100  contains three or more types of the magnetic metal powder particles  11  to  13  having different diameters, a charging ratio of a magnetic body of the body  100  can be enhanced, and characteristics of a component, such as inductance, can be improved. As used herein, the expression “diameter” of the magnetic metal powder particles  11  to  13  may refer to particle distribution such as D 50  or D 90 . Accordingly, different diameters of the magnetic metal powder particles  11  to  13  may refer to different numerical values of the particle distribution, such as D 50  or D 90 . 
     The insulating resin R may contain epoxy, polyimide, a liquid crystal polymer, or the like, independently or a mixture thereof, but is not limited thereto. 
     The first magnetic metal powder particle  11  is described below. 
     The second and third magnetic metal powder particles  12  and  13  contain magnetic metal particles  12 - 1  and  13 - 1  and insulating layers  12 - 2  and  13 - 2  surrounding the magnetic metal particles  12 - 1  and  13 - 1 , respectively, and containing an insulating resin R′. The insulating resin R′ may be the same or different material from the insulating resin R included in the body, which filled with all the part of the space not occupied by the first, second and third magnetic metal powder particles. 
     The magnetic metal particles  12 - 1  and  13 - 1  may contain at least one selected from the group consisting of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), boron (B) and nickel (Ni). For example, each of the magnetic metal particles  12 - 1  and  13 - 1  may be a Fe—Si—B—Nb—Cu-base alloy powder. 
     The magnetic metal particles  12 - 1  and  13 - 1  may contain at least one selected from the group consisting of Fe, Si, Cr, Co, Mo, Al, Nb, Cu and Ni. For example, the magnetic metal particles  12 - 1  and  13 - 1  may contain at least one of a pure iron powder, a Fe—Si alloy powder, a Fe—Si—Al alloy powder, a Fe—Ni alloy powder, a Fe—Ni—Mo alloy powder, Fe—Ni—Mo—Cu alloy powder, a Fe—Co alloy powder, a Fe—Ni—Co alloy powder, a Fe—Cr alloy powder, a Fe—Cr—Si alloy powder, a Fe—Si—Cu—Nb alloy powder, a Fe—Ni—Cr alloy powder, a Fe—Cr—Al alloy powder or a Fe—Si—B—Nb—Cu alloy powder. 
     The magnetic metal particles  12 - 1  and  13 - 1  may be amorphous or crystalline. For example, the magnetic metal particles  12 - 1  and  13 - 1  may be a Fe—Si—B—Nb—Cu alloy powder may be a crystal grain containing iron silicide (Fe 3 Si) in an amorphous matrix, but is not limited thereto. 
     The insulating coating layers  12 - 2  and  13 - 2  may contain an electrically insulating resin, such as an epoxy resin or a polyimide resin, but are not limited thereto. The insulating coating layers  12 - 2  and  13 - 2  may have a thickness of greater than 0.01 μm and less than 1 μm, but are not limited thereto. A thickness of the insulating coating layers  12 - 2  may be obtained by an arithmetic mean of thicknesses of the insulating coating layers  12 - 2  of one particular particle of the second magnetic metal powder particles shown in SEM image or TEM image. The insulating coating layers  12 - 2  and  13 - 2  may be formed on surfaces of the magnetic metal particles  12 - 1  and  13 - 1  by immersing the magnetic metal particles  12 - 1  and  13 - 1  in a liquid insulating resin and drying the same, but are not limited thereto. The thickness can be measured by a method other than the method of using SEM image or TEM image, which is appreciated by the one skilled in the art. 
     A diameter of the second magnetic metal powder particle  12  may be greater than that of the first magnetic metal powder particle  11 , and a diameter of the third magnetic metal powder particle  13  may be greater than that of the second magnetic metal powder particle  12 . As an example, the diameter of the first magnetic metal powder particle  11  may be less than 1 μm. More preferably, the diameter of the first magnetic metal powder particle  11  may be 0.1 μm to 0.2 μm. The diameter of the second magnetic metal powder particle  12  may be 1 μm to 2 μm, and the diameter of the third magnetic metal powder particle  13  may be 25 μm to 30 μm. In the case in which the diameter of the second magnetic metal powder particle  12  is beyond said range, the magnetic body charging percentage of the body  100  may be reduced. In the case in which the diameter of the third magnetic metal powder particle  13  is below 25 μm, the magnetic body charging percentage of the body  100  may be reduced. When the diameter of the third magnetic metal powder particle  13  exceeds 30 μm, occurrence of an outer appearance defect may increase and a binding force between the external electrodes  400  and  500  and the body  100  may decrease while plating spreading may be generated during plating of the external electrodes  400  and  500 . 
     The first magnetic metal powder particle  11  includes a core  11 - 1  represented by Formula 1 below, and an oxide film  11 - 2  formed on a surface of the core  11 - 1  and containing at least one of Si or Cr:
 
Fe a Si b Cr c   [Formula 1]
 
     where 3 atom %≤b≤6 atom %, 2.65 atom %≤c≤3.65 atom %, and a+b+C=100. 
     For trimodal (meaning that a coil component contains three types of magnetic metal powder particles with different diameters), an insulating coating layer is simply and easily formed on surfaces of a magnetic metal powder particle having a largest diameter (coarse magnetic metal powder particle) and that having a median diameter (fine powder magnetic metal powder particle) using a liquid phase process due to relatively large diameters thereof. In contrast, it is difficult to form an insulating coating layer on a surface of a magnetic metal powder particle having a smallest diameter (less than 1 μm; ultrafine magnetic metal powder particle) due to the current liquid phase process. Due to a short circuit between the ultrafine magnetic metal powder particles, leakage voltage may be reduced. 
     In the present disclosure, the above mentioned problems are resolved by the first magnetic metal powder particle  11 , the ultrafine magnetic metal powder particle, by forming the core and the oxide film  11 - 2  having an oxidized surface itself on a surface of the core  11 - 1 . The oxide film  11 - 2  is a native oxide and may thus contain at least one of Si or Cr contained in the core  11 - 1 . That is, the oxide film  11 - 2  may contain at least one of a Si—O bonding or a Cr—O bonding. In the present disclosure, as the first magnetic metal powder particle  11  contains the core  11 - 1  and the oxide film  11 - 2 , which is the native oxide of the core  11 - 1 , insulation resistance of the first magnetic metal powder particle  11  can be obtained by a comparatively easy method. 
     By satisfying the composition of Formula 1, the core  11 - 1  may form an oxide film  11 - 2  having enhanced insulation resistance characteristics on a surface thereof. When a content (at o) of Si of the core  11 - 1  is less than the range of Formula 1, the oxide film  11 - 2  is insufficiently formed on the surface o f the core  11 - 1 , thereby giving rise to reduced insulation resistance. This will be described below. When a content (at o) of Si of the core  11 - 1  exceeds the range of Formula 1, a volume accounted for by the oxide film  11 - 2  in the entire first magnetic metal powder particle  11  extremely increases, and the component characteristics, such as inductance, may decrease. 
     The body  100  includes a core  110  penetrating the coil portion  300 , which will be described below. The core  110  may be formed by filling a penetrating hole of the coil portion  300  by at least a portion of a magnetic complex sheet in the process in which the magnetic composite sheet is stacked and cured, but is not limited thereto. 
     The insulating substrate  200  is embedded in the body  100 . The insulating substrate  200  is configured to support the coil portion  300 . 
     The insulating substrate  200  is formed of an insulating material such as a thermosetting insulating resin such as an epoxy resin, a thermoplastic insulating resin such as a polyimide, or a photosensitive insulating resin, or may be formed of an insulating material in which a reinforcing material such as a glass fiber or an inorganic filler is impregnated with such an insulating resin. For example, the internal insulating layer  200  may be formed of an insulating material such as prepreg, Ajinomoto Build-up Film (ABF), FR-4, a bismaleimide triazine (BT) resin, a photoimageable dielectric (PID), and the like, but an example of the material of the internal insulating layer is not limited thereto. 
     As the inorganic filler, one or more materials selected from a group consisting of silica (SiO 2 ), alumina (Al 2 O 3 ), silicon carbide (SiC), barium sulfate (BaSO 4 ), talc, mud, a mica powder, aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium carbonate (CaCO 3 ), magnesium carbonate (MgCO 3 ), magnesium oxide (MgO), boron nitride (BN), aluminum borate (AlBO 3 ), barium titanate (BaTiO 3 ), and calcium zirconate (CaZrO 3 ) may be used. 
     When the insulating substrate  200  is formed of an insulating material including a reinforcing material, the insulating substrate  200  may provide improved stiffness. When the insulating substrate  200  is formed of an insulating material which does not include a glass fiber, the insulating substrate  200  is advantageous in component slimming. When the insulating substrate  200  is formed of an insulating material including a photosensitive insulating resin, a number of processes for forming the coil portion  300  may be reduced such that manufacturing costs are reduced, and it is advantageous in forming a fine via  320 . 
     The coil portion  300  includes planar spiral coil patterns  311  and  312  and is buried in the body  100  to exhibit the characteristics of the coil component. For example, when the coil component  1000  is used as a power inductor, the coil portion  300  may store an electric field as a magnetic field such that an output voltage may be maintained, thereby stabilizing power of an electronic device. 
     The coil portion  300  may include coil patterns  311  and  312  and a via  320 . Specifically, based on the directions of  FIGS.  1  to  3   , a first coil pattern  311  is disposed on a lower surface of the insulating substrate  200  facing the sixth surface  106  of the body  100 , while the second coil pattern  312  is disposed on an upper surface of the insulating substrate. The via  320  penetrates the insulating substrate  200  to be in contact with inner end portions of the first and second coil patterns  311  and  312 . This enables the coil portion  300 , as a whole, to function as a single coil in which one or more turns are formed based on the core  110 . 
     The first and second coil patterns  311  and  312  have a planar spiral shape in which at least one turn is formed based on the core  110 . As an example, the first coil pattern  311  may form at least one turn based on the core  110  on the lower surface of the insulating substrate  200  with respect to the directions of  FIGS.  1  to  3   . 
     External ends of the first and second coil patterns  311  and  312  are exposed to the first and second surfaces  101  and  102 , respectively, to be in contact with the first and second external electrodes  400  and  500 . That is, the external end of the first coil pattern  311  is connected to the first external electrode  400  and that of the second coil pattern  312  is connected to the second external electrode  500 . 
     The first coil pattern  311  includes a first conductive layer  311   a  contact-formed on the lower surface of the insulating substrate  200  based on the directions of  FIGS.  4  and  5    and a second conductive layer  311   b  disposed on the first conductive layer  311   a.    
     The first conductive layer  311   a  may be a seed layer for forming the second conductive layer  311   b  by electroplating. The first conductive layer  311   a , the seed layer of the second conductive layer  311   b , is formed to be thinner than the second conductive layer  311   b . The first conductive layer  311   a  may be formed by an electroless plating process of a thin film process such as sputtering. When the conductive layer  311   a  is formed by a thin film process such as sputtering, at least a portion of materials forming the first conductive layer  311   a  may be permeated into the lower surface of the insulating substrate  200 . This can be confirmed by the fact that a difference occurs in a concentration of a metal material forming the first conductive layer  311  in the insulating substrate  200  along a thickness direction T of the body  100 . 
     A thickness of the first conductive layer  311   a  may be 1.5 μm to 3 μm. When the thickness of the first conductive layer  311   a  is less than 1.5 μm, the first conductive layer  311   a  is not easily achieved, thereby causing a plating defect to possibly occur in subsequent processes. When the thickness of the first conductive layer  311   a  is greater than 3 μm, it is difficult to form the second conductive layers  311   b  and  312   b  to have comparatively large volumes in a limited volume of the body  100 . For example, based on any one turn of the first coil pattern  311  shown in the optical micrograph for the length-thickness cross-section (a LT cross-section) in the central portion of the body  100  in the width direction W, the thickness of the first conductive layer  311   a  may refer to, when the normal extends in the thickness direction T from one point of a line segment corresponding to one surface of the first conductive layer  311   a  contacting one surface of the support substrate  200  (the lower surface of the support substrate  200  based on the direction in  FIGS.  5 ,  6   ), a distance from the one point to the other point at which the normal contacts a line segment corresponding to the other surface of the first conductive layer  311   a , opposing one surface of the first conductive layer  311   a.    
     Alternatively, for example, based on anyone turn of the first coil pattern  311  illustrated in the optical micrograph for the length-thickness cross-section (the LT cross-section) in the central portion of the body in the width direction W, when a plurality of normals extend in the thickness direction T from a plurality of one points of a line segment corresponding to one surface of the first conductive layer  311   a  contacting one surface of the support substrate  200  (the lower surface of the support substrate  200  based on the direction in  FIGS.  5 ,  6   ), the thickness of the first conductive layer  311   a  may indicate an arithmetic mean of distances from the plurality of one points to a plurality of the other points at which the plurality of normals are in contact with a line segment corresponding to the other surface of the first conductive layer  311   a , opposing one surface of the first conductive layer  311   a.    
     Alternatively, based on the optical micrograph of the length-thickness cross-section (the LT cross-section) in the central portion of the body in the width direction W, the thickness of the first conductive layer  311   a  may indicate an arithmetic mean of respective thicknesses of the plurality of turns illustrated in the cross-sectional image by the above-described method. 
     The thickness can be measured by a method other than the method described above, which is appreciated by the one skilled in the art. 
     Based on  FIG.  5   , in some embodiments, at least a portion of a side surface of the first conductive layer  311   a  is exposed by the second conductive layer  311   b . In the case of  FIG.  5   , a seed film for forming the first conductive layer  311   a  is formed on the entire lower surface of the insulating substrate  200 , and a plating resist for forming the second conductive layer  311   b  is formed on the seed film. The second conductive layer  311   b  is then formed by electroplating followed by removing the plating resist and selectively removing the seed film on which the second conductive layer  311   b  is not formed, resulting in formation of the first coil pattern  311 . Accordingly, the at least a portion of the side surface of the first conductive layer  311   a  formed by selectively removed seed film is not covered by the second conductive layer  311   b  but is exposed thereby. The seed film may be formed on the lower surface of the insulating substrate  200  by electroless plating or sputtering. Alternately, the seed film may be a cupper foil of a copper clad laminate (CCL). The plating resist may be formed by applying a material for forming the plating resist to the seed film and then performing a photolithography process. After the photolithography process, the plating resist may have an opening corresponding to a region in which the second conductive layer  311   b  is to be formed. The selective removal of the seed film may be performed by a laser process and/or an etching process. When the seed film is selectively removed by etching, the first conductive layer  311   a  may be formed in the form in which a cross-sectional area increases as it approaches the insulating substrate  200  from the second conductive layer  311   b.    
     Based on  FIG.  6   , in some embodiments, the second conductive layer  311   b  covers the first conductive layer  311   a . In contrast to  FIG.  5   ,  FIG.  6    involves forming the planar spiral first conductive layer  311   a  on the lower surface of the insulating substrate  200  and the second conductive layer  311   b  on the first conductive layer  311   a  by electroplating. When the second conductive layer  311   b  is formed by anisotropic plating, a plating resist may not be used, but the present disclosure is not limited thereto. That is, when the second conductive layer  311   b  is formed, a plating resist for forming the second conductive layer may be used. An opening exposing the first conductive layer  311   a  is formed in the plating resist for forming the second conductive layer. A diameter of the opening may be larger than a line width of the first conductive layer  311   a , and as a result, the second conductive layer  311   b  filling the opening covers the side surface of the first conductive layer  311   a  and  312   a  to be in contact with the insulating substrate  200 . 
     Meanwhile, the descriptions above regarding the first and second conductive layers  311   a  and  311   b  of the first coil pattern  311  may be similarly applied to the first and second conductive layers  312   a  and  312   b  of the second coil pattern  312 . 
     The via  320  may include at least one conductive layer. As an example, when the via  320  is formed by electroplating, the via  320  may include a seed layer formed on an inner wall of a via hole penetrating the insulating substrate  200  and an electroplating layer filling the via hole in which the seed layer is formed. The seed layer of the via  320  may be integrally formed with the first conductive layers  311   a  and  312   a  in the same process, or formed in different processes thereby forming a boundary therebetween. The electroplating layer of the via  320  may be integrally formed with the second conductive layers  311   b  and  312   b  in the same process, or formed in different processes thereby forming a boundary therebetween. 
     When the line width of the coil patterns  311  and  312  is extremely large, a volume accounted for by the magnetic body in the body  100  is reduced, thereby negatively affecting inductance. As a non-limited example, an aspect ratio (AR) of the coil patterns  311  and  312  may be 3:1 to 9:1. 
     The coil patterns  311  and  312  and the via  320  may be formed of Cu, Al, Ag, Sn, Au, Ni, Pd, Ti, Cr or alloys thereof, but are not limited thereto. As a non-limited example, when the first conductive layers  311   a  and  312   a  are formed by sputtering and the second conductive layers  311   b  and  312   b  are formed by electroplating, the first conductive layers  311   a  and  312   a  may contain at least one of Mo, Cr, Cu and Ti, while the second conductive layers  311   b  and  312   b  may contain Cu. As another non-limited example, when the first conductive layers  311   a  and  312   a  are formed by electroless plating and the second conductive layers  311   b  and  312   b  are formed by electroplating, the first and second conductive layers  311   a ,  312   a ,  311   b  and  312   b  may contain Cu. In this case, a density of Cu in the first conductive layers  311   a  and  312   a  may be lower than that in the second conductive layers  311   b  and  312   b.    
     The external electrodes  400  and  500  are disposed on a surface of the body  100  and are connected to both ends of the coil portion  300 . In the present exemplary embodiment, both ends of the coil portion  300  are exposed to the first and second surfaces  101  and  102  of the body  100 , respectively. Accordingly, the first external electrode  400  is disposed on the first surface  101  to be contact-connected to the end of the first coil pattern  311  exposed to the first surface  101  of the body, while the second external electrode  500  is disposed on the second surface  102  to be contact-connected to the end of the second coil pattern  312  exposed to the second surface  103  of the body  100 . 
     The external electrodes  400  and  500  may be formed of a conductive material, such as Cu, Al, Ag, Sn, Au, Ni, Pb, Ti or alloys thereof, but is not limited thereto. 
     The external electrodes  400  and  500  may be formed in a single layer or multiple layers. As an example, the first external electrode  400  may be formed to have a first layer containing Cu, a second layer disposed on the first layer and containing Ni and a third layer disposed on the second layer and containing Sn. The first to third layers may be formed by plating but are not limited thereto. As another example, the first electrode layer  400  may include a resin electrode layer containing a conductive powder and a resin, and a plating layer plated on the resin electrode layer. In this case, the resin electrode layer may contain a cured product of a thermosetting resin and at least one conductive powder of Cu and Ag. Further, the plating layer may include a first plating layer containing Ni and a second plating layer containing Sn. When the resin contained in the resin electrode layer contains a resin identical to the insulating resin R of the body  100 , a binding force between the resin electrode layer and the body  100  may be enhanced. 
     The insulating film  500  may be formed on the insulating substrate  200  and the coil portion  300 . The insulating film  500  is to insulate the coil portion  300  from the body  100 , and may contain a known insulating material such as parylene. Any insulating material can be contained in the insulating film  600  and is not particularly limited. The insulating film  600  may be formed by a vapor deposition method, or the like, but is not limited thereto. The insulating film  600  may be formed by stacking insulating films on both surface of the insulating substrate  20 . In the former case, the insulating film  600  may be formed in the form of a conformal film along a surface of the coil portion  300  and the insulating substrate  200 . In this case, at least some of the magnetic metal powder particles  11  to  13  may be filled in a space between turns adjacent to the coil patterns  311  and  312  in which the conformal insulating film  600  is formed. In the latter case, the insulating film  600  may be formed in the form of filling the space between the turns adjacent to the coil patterns  311  and  312 . Meanwhile, as previously described, the plating resist for forming the second conductive layers  311   b  and  312   b  may be formed on the insulating substrate  200 , and such plating resist may be permanent and is not removed. In this case, the insulating film  600  may be a plating resist, a permanent resist. Meanwhile, the insulating film  600  in the present disclosure is a selective configuration, and may thus be omitted as long as the body  100  can secure sufficient insulation resistance under the operational conditions of the coil component  1000  according to the present exemplary embodiment. 
     Experimental Examples 1 to 3 below are carried out by preparing the coil components comprising a body including the first magnetic metal powder particle, the second magnetic metal powder particle and the third magnetic metal powder particle while varying the contents (at %) of Si in the core of the first magnetic metal powder. 
     In Table 1 below, the expression “independent leakage voltage” is a leakage voltage measured only for the first magnetic metal powder. The expression “trimodal leakage voltage” is a leakage voltage of the body measured after the body containing the second and third magnetic metal powder particles is formed. 
     Meanwhile, Experimental Examples 1 to 3 are identical except the Si contents (at %) of the core  11 - 1 . That is, a diameter of the first magnetic metal powder particle and a weight percentage (wt %) based on the entire body are identical in Experimental Examples 1 to 3 (so do the second and third magnetic metal powder particles). Further, the compositions of the second and third magnetic metal powder particles are identical in Experimental Examples 1 to 3. Also, the second magnetic metal powder had a larger diameter than the first magnetic metal powder particle, and the third magnetic metal powder particle had a larger diameter than the second magnetic metal powder particle. The first magnetic metal powder of Experimental Examples 1 to 3 included the core represented by Formula 1 except for that the silicon contents were specified in Table 1 below. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                   
                   
                 Independent Leakage Voltage 
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 Si 
                 Leakage 
                 Leakage 
                 Trimodal Leakage 
               
               
                   
                   
                 (at %) 
                 Voltage (V) 
                 Voltage (V/mm) 
                 Voltage (V/mm) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 1 
                 2.017 
                 12.25 
                 4.62 
                 10.7 
               
               
                   
                 2 
                 3.104 
                 1000 
                 329.32 
                 34.3 
               
               
                   
                 3 
                 4.161 
                 1000 
                 357.91 
                 82.1 
               
               
                   
                   
               
            
           
         
       
     
     Based on Table 1, Experimental Examples 2 and 3 satisfying the range of Formula 1 show increased leakage voltage and trimodal leakage voltage and thus increased insulation resistance characteristics. 
     Specifically, Experimental Example 1, which does not satisfy the range of Formula 1 with respect to the Si content, exhibits deteriorated insulation resistance characteristics due to insufficient formation of oxide films on the surface of the core. In the case of Experimental Examples 2 and 3 satisfying the range of Formula 1 with respect to the Si content, however, a silicon oxide film is formed on the surface of the core to have a sufficient thickness, thereby giving rise to enhanced insulation resistance characteristics of the first magnetic metal powder particle itself as well as the trimodal body containing the first magnetic metal powder particles. 
       FIG.  7    is a schematic diagram illustrating a coil component according to another exemplary embodiment, and  FIG.  8    is a diagram illustrating the coil component of  FIG.  7    viewed from a lower portion.  FIG.  9    is a schematic diagram illustrating a coil component according to Experimental Example 3 and corresponding to the cross-section taken along line I-I′ of  FIG.  1   , and  FIG.  10    is a cross-sectional view taken along line of  FIG.  7   . 
     Based on  FIGS.  1  to  6    together with  FIGS.  7  to  10   , a coil component  2000  according to the present exemplary embodiment is different in terms of the coil portion  300  and the external electrodes  400  and  500  when compared to the coil component  1000  according to the previous exemplary embodiment. Accordingly, the coil portion  300  and the external electrodes  400  and  500  will only be described based on the differences therebetween. The description of the remaining constitutions in the previous exemplary embodiment can be applied, as it is or modified, to the present exemplary embodiment. 
     The coil portion  300  applied to the present exemplary embodiment includes coil patterns  311  and  312 , lead-out patterns  331  and  332 , auxiliary lead-out patterns  341  and  342  and vias  321 ,  322  and  323 . 
     Specifically, based on the directions of  FIGS.  7  to  10   , a first coil pattern  311 , a first lead-out pattern  331  and a second lead-out pattern  332  are disposed on the lower surface of the insulating substrate  200  facing the sixth surface  106  of the body, and a second coil pattern  312 , a first auxiliary lead-out pattern  341  and a second auxiliary lead-out pattern  342  are disposed on the upper surface of the insulating substrate  200  facing the fifth surface  105  of the body. The lead-out patterns  331  and  332  of the present exemplary embodiment are configured to be contact-connected to the external electrodes  400  and  500 , similarly to both ends of the first and second coil patterns  311  and  312  described in the previous exemplary embodiment. 
     Based on  FIGS.  7 ,  9  and  10   , the first coil pattern  311  is in contact with the first lead-out pattern  331  on the lower surface of the insulating substrate, and the first coil pattern  311  and the first lead-out pattern  331  are spaced apart from the second lead-out pattern  332 . The second coil pattern  312  is in contact with the second auxiliary lead-out pattern  342  on the upper surface of the insulating substrate  200 , and the second coil pattern  312  and the second auxiliary lead-out pattern  342  are spaced apart from the first auxiliary lead-out pattern  341 . The first via  321  penetrates the insulating substrate  200  to be in contact with inner ends of the first and second coil patterns  311  and  312 , and the second via  322  penetrates the insulating substrate  200  to be in contact with the second lead-out pattern  332  and the second auxiliary lead-out pattern  342 . This enables the coil portion  200  as a while to function as a single coil. 
     The lead-out patterns  331  and  332  and the auxiliary lead-out patterns  341  and  342  are exposed to both cross-sections of the body  100 . That is, the first lead-out pattern  331  and the first auxiliary lead-out pattern  341  are exposed to the first surface  101  of the body  100  and the second lead-out pattern  332  and the second auxiliary lead-out pattern  342  are exposed to the second surface  102  of the body  100 . 
     At least one of the coil patterns  311  and  312 , the vias  321 ,  322  and  323 , the lead-out patterns  331  and  332  and the auxiliary lead-out patterns  341  and  342  may include at least one conductive layer. 
     As an example, when the second coil pattern  312 , the auxiliary lead-out patterns  341  and  342  and the vias  321 ,  322  and  323  are formed plated on the other surface of the insulating substrate  200 , each of the second coil pattern  312 , the auxiliary lead-out patterns  341  and  342  and the vias  321 ,  322  and  323  may include at least one conductive layer such as a seed layer and/or an electroplating layer. The seed layer may be an electroless plating layer. In this case, the electroplating layer may have a single layer structure or a multilayer structure. The multilayered electroplating layer may be formed in the form of a conformal film, in which one electroplating layer is covered by another electroplating layer, or in the form in which an electroplating layer is stacked only on one surface of another electroplating layer. The seed layer of the second coil pattern  312 , those of the auxiliary lead-out patterns  341  and  342  and those of the vias  321 ,  322  and  323  are integrally formed and may thus not have a boundary formed therebetween, but are not limited thereto. The electroplating layer of the second pattern  312 , those of the auxiliary lead-out patterns  341  and  342  and those of the vias  321 ,  322  and  323  are integrally formed and may thus not have a boundary formed therebetween, but are not limited thereto. 
     Based on  FIGS.  7  and  10   , the coil patterns  311  and  312 , the lead-out patterns  331  and  332  and the auxiliary lead-out patterns  341  and  342  may be formed to extrude from the lower and upper surfaces of the insulating substrate  200 . As another example, the first coil pattern  311  and the lead-out patterns  331  and  332  are formed to extrude from the lower surface of the insulating substrate  200 , and the second coil pattern  312  and the auxiliary lead-out patterns  341  and  342  are embedded in the upper surface of the insulating substrate  200  such that the upper surface of each of the second coil pattern  312  and the auxiliary lead-out patterns  341  and  342  are exposed onto the upper surface of the insulating substrate  200 . In this case, a recess portion is formed on the upper surface of the second coil pattern  312  and/or the auxiliary lead-out patterns  341  and  342 , thereby making the upper surface of the second coil pattern  312  and/or the auxiliary lead-out patterns  341  and  342  and that of the insulating substrate  200  not on the same planar, and vice versa as another example. 
     The coil patterns  311  and  312 , the lead-out patterns  331  and  332 , the auxiliary lead-out patterns  341  and  342  and the vias  321 ,  322  and  323  may be formed of a conductive material such as Cu, Al, Ag, Sn, Au, Ni, Pb, Ti or alloys thereof, but are not limited thereto. 
     Meanwhile, based on  FIG.  9   , the auxiliary lead-out pattern  341  is irrelevant to electrical connections between the remaining configurations of the coil portion  300  and may thus be omitted. However, it is preferable that the first auxiliary lead-out pattern  341  be formed to skip a process of distinguishing the fifth and sixth surfaces of the body  100 . 
     The first and second external electrodes  400  and  500  include first and second connection portion  420  and  520  and first and second pad portions  410  and  510  spaced apart from each other on the sixth surface  106  of the body  100 . Specifically, the first external electrode  400  includes the first pad portion  410  formed on the sixth surface  106  of the body  100  and the first connection portion  420  penetrating at least a portion of the body  100  to be contact-connected to the first lead-out pattern  331  of the coil portion  300  and the first pad portion  410 . The second external electrode  500  includes the second pad portion  510  formed on the sixth surface  106  of the body  100  and the second connection portion  520  penetrating at least a portion of the body  100  to be contact-connected to the second lead-out pattern  332  of the coil portion  300  and the second pad portion  510 . 
     The first and second pad portions  410  and  510  may be formed in a single layer or multiple layers. As an example, the first pad portion  410  may be formed to have a first layer containing Cu, a second layer disposed on the first layer and containing Ni and a third layer disposed on the second layer and containing Sn. 
     The first and second connection portions  420  and  520  penetrate at least a portion of the body  100 . That is, in the case of the present exemplary embodiment, the first and second pad portions  410  and  510  are connected to the first and second lead-out patterns  331  and  332  through the first and second connection portions  420  and  520  disposed inside the body; the first and second external electrodes  400  and  500  are not connected to the first and second lead-out patterns  331  and  332  through the surface of the body  100 . 
     The first and second connection portions  420  and  520  may extend from the coil portion  300 . As an example, the first and second connection portions  420  and  520  may grow by plating from the first and second lead-out patterns  331  and  332  exposed through an opening of a plating resist after forming the plating resist having the opening on the first and second lead-out patterns  331  and  332 . Alternately, the first and second connection portions  420  and  520  may be formed by forming the body  100  and forming a via hole on the sixth surface of the body  100  followed by filling a conductive material in the via hole. In the former case, the first and second lead-out patterns  331  and  332  may serve as feeding layers in forming the first and second connection portions  420  and  620  by electroplating. As a result, a seed layer, such as an electroless plating layer, may not be present at a boundary between the first and second connection portions  420  and  520  and the coil portion  300 , but is not limited thereto. In the latter case, the first and second connection portions  420  and  520  may include a seed layer formed inside the via hole, but are not limited thereto. 
     Meanwhile,  FIGS.  7 ,  8  and  10    illustrate each of the first and second connection portions  420  and  520  unitarily formed to have a cylindrical shape; however, this is merely for convenience in illustration and description thereof. As another non-limited example, the first connection portion  420  may be formed in plural and in the form of a square pillar. 
       FIG.  11    is a schematic diagram illustrating a magnetic composite sheet according to an exemplary embodiment, and  FIG.  12    an enlarged view of “C” of  FIG.  11   . 
     Based on  FIGS.  11  and  12   , a magnetic composite sheet  3000  according to an exemplary embodiment includes a first magnetic metal powder particle  11 , a second magnetic metal powder particle  12 , a third magnetic metal powder particle  13  and an insulating resin R. 
     The first to third magnetic metal powder particles  11  to  13  are described in the coil component  1000  according to the one exemplary embodiment above, and the description thereof will be omitted. 
     Meanwhile, the insulating resin R of the magnetic composite sheet  3000  according to the present exemplary embodiment, in contrast to that described in the coil component  1000  of one of the previous exemplary embodiments, is uncured or semi-cured. That is, the insulating resin R of the present disclosure is uncured or semi-cured in the magnetic composite sheet  3000  as in the present exemplary embodiment and becomes cured in the body  100  formed by stacking such magnetic composite sheet  3000  on the insulating substrate  200  and curing the same. 
     Meanwhile, although not illustrated, the magnetic composite sheet  3000  according to the present exemplary embodiment may include a functional layer containing the first to third magnetic metal powder particles  11  to  13  and the insulating resin R, a support film disposed on one surface of the functional layer and a protective film on the other surface of the functional layer. In the case of the magnetic composite sheet  3000 , the protective film is removed such that the functional layer faces the insulating substrate  200  and stacked thereon. The stacked support film may then be removed. 
     As set forth above, according to the present disclosure, a leakage current of a coil component containing three or more magnetic metal powder particles having different diameters can be reduced. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the appended claims.