Abstract:
A coil electronic component includes: a magnetic body comprising a magnetic material; a coil part embedded inside the magnetic body; and a magnetic layer disposed on a surface of the magnetic body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2015-0022132, filed in the Korean Intellectual Property Office on Feb. 13, 2015, the entire disclosure of which is incorporated herein by reference for all purposes. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The following description relates to a coil electronic component and manufacturing method thereof. 
         [0004]    1. Description of Related Art 
         [0005]    An inductor, which is a chip electronic component, is a representative passive element for configuring an electronic circuit together with a resistor and a capacitor for removing noise. 
         [0006]    The thin layer inductor is manufactured by forming a coil part by a plating process, forming a magnetic body by hardening a magnetic-resin compound that is a mixture of a magnetic powder and a resin, and forming external contacts on outer surfaces of the magnetic body. 
       SUMMARY 
       [0007]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
         [0008]    According to one general aspect, a coil electronic component includes: a magnetic body comprising a magnetic material; a coil part embedded in the magnetic body; and a magnetic layer disposed on a surface of the magnetic body. 
         [0009]    The magnetic layer may include a metallic layer. 
         [0010]    The magnetic layer may be formed by a plating process. 
         [0011]    The coil electronic component may further include a plating seed layer disposed between the surface of the magnetic body and the magnetic layer. 
         [0012]    The coil electronic component may further include an insulating cover layer disposed on the magnetic layer. 
         [0013]    The magnetic layer may be formed of a metal or an alloy that includes at least one of iron (Fe), silicon (Si), boron (B), chromium (Cr), aluminum (Al), copper (Cu), niobium (Nb), or nickel (Ni). 
         [0014]    The coil part may include a lead part that extends to a portion of the surface of the magnetic body, and the magnetic layer may be disposed only on portions of the surface of the magnetic body other than the portion of the surface of the magnetic body to which the lead part extends. 
         [0015]    The magnetic material may include a metallic magnetic powder and a thermosetting resin. 
         [0016]    The coil part may be formed by a plating process. 
         [0017]    According to another general aspect, a manufacturing method of a coil electronic component includes: forming a coil part; forming a magnetic body by stacking magnetic sheets above and below the coil part, each of the magnetic sheets comprising a metallic magnetic powder and a thermosetting resin; and forming a magnetic layer on a surface of the magnetic body. 
         [0018]    The method may further include forming the magnetic layer by a plating process. 
         [0019]    The method may further include forming a plating seed layer on the surface of the magnetic body before the forming of the magnetic layer on the surface of the magnetic body. 
         [0020]    The method may further include, after the forming of the magnetic layer, removing, by an etching process, a portion of the magnetic layer on a portion of the surface of the magnetic body to which a lead part of the coil part extends. 
         [0021]    The method may further include, after the forming of the magnetic layer, forming an insulating cover layer on the magnetic layer. 
         [0022]    The magnetic layer may include a metal or an alloy including at least one of iron (Fe), silicon (Si), boron (B), chromium (Cr), aluminum (Al), copper (Cu), niobium (Nb), or nickel (Ni). 
         [0023]    According to another general aspect, a coil electronic component includes: a body including first and second end surfaces, first and second side surfaces, and first and second main surfaces, wherein the first and second main surfaces extend between the first and second end surfaces and between the first and second side surfaces; a coil part embedded in the magnetic body and including lead parts extending to the first and second end surfaces; and a magnetic layer disposed only on the first and second side surfaces and the first and second main surfaces. 
         [0024]    The coil electronic component may further include external contacts disposed on the first and second end surfaces, and connected to the lead parts. 
         [0025]    Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a schematic perspective view of a coil part of a chip electronic component according to an example; 
           [0027]      FIG. 2  is a cross-sectional view taken along line I-I′ of  FIG. 1 ; 
           [0028]      FIG. 3  is a cross-sectional view taken along line II-II′ of  FIG. 1 ; 
           [0029]      FIGS. 4 through 9  are views schematically describing an example of a manufacturing method of the coil electronic component. 
       
    
    
       [0030]    Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
       DETAILED DESCRIPTION 
       [0031]    The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent to one of ordinary skill in the art. The sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Also, descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted for increased clarity and conciseness. 
         [0032]    The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided so that this disclosure will be thorough and complete, and will convey the full scope of the disclosure to one of ordinary skill in the art. 
         [0033]    Chip Electronic Component 
         [0034]    Hereinafter, an example of a coil electronic component, particularly, a thin layer inductor, will be described. However, the disclosure is not limited thereto. 
         [0035]      FIG. 1  is a schematic perspective view of a coil part of a chip electronic component according to an example. 
         [0036]    Referring to  FIG. 1 , a thin layer power inductor used for a power line of a power supply circuit is illustrated as a coil electronic component  100 , by way of example. 
         [0037]    The coil electronic component  100  includes include a magnetic body  50 , a coil part  40  that is embedded inside of the magnetic body  50 , and a first external contact  81  and a second external contact  82  that are arranged on the outer surfaces of the magnetic body  50  and electrically connected to the coil part  40 . 
         [0038]    In the chip electronic component  100 , X, W and T in  FIG. 1  respectively refer to a length direction, a width direction, and a thickness direction. 
         [0039]    The magnetic body  50  includes first and second end surfaces S L1  and S L2  that face to each other in the length direction X, first and second side surfaces S W1  and S W2  that connect the first and second end surfaces S L1  and S L2  and face to each other in the width direction W, and first and second main surfaces S T1  and S T2  that face to each other in the thickness direction T. The magnetic body  50  may include any magnetic material that exhibits magnetic properties, for example, a ferrite or a metallic magnetic powder. 
         [0040]    The coil part  40  is formed by coupling a first coil conductor  41  that is formed on one surface of a substrate  20  that is arranged inside the magnetic body  50  to a second coil conductor  42  that is formed on another surface that faces the one surface of the substrate  20 . 
         [0041]    The first and the second coil conductors  41  and  42  may each have a planar coil shape that is formed on the respective surface of the substrate  20 . Alternatively, the first coil conductor  41  and the second coil conductor  42  may have a spiral shape. The first and second coil conductors  41  and  42  may be formed, for example, by performing an electroplating process on the substrate, but are not limited to being formed in such a manner. 
         [0042]    The substrate  20  may be, for example, a polypropylene glycol (PPG) substrate, a ferrite substrate, a metal based soft magnetic substrate, or the like. 
         [0043]    The substrate  20  may have a through hole formed in a central portion thereof, and the through hole may be filled with a magnetic material to from a core part  55  within the magnetic body  50 . The core part  55  filled with the magnetic material may increase an inductance L. 
         [0044]    A magnetic layer  62  is formed on the coil part  40 . The magnetic layer  62  according to an example will be described in detail below. 
         [0045]    An insulating cover layer  70  is formed on the magnetic layer  62 . By forming the insulating cover layer  70  to cover the magnetic layer  62 , a short-circuit defect due to the magnetic layer  62  can be prevented. 
         [0046]      FIG. 2  is a cross-sectional view taken along line I-I′ of  FIG. 1   
         [0047]    Referring to  FIG. 2 , the magnetic body  50  includes a metallic magnetic powder  51 . 
         [0048]    The metallic magnetic powder  51  may be a crystalline or amorphous metal or an alloy that includes at least one of iron (Fe), silicon (Si), boron (B), chromium (Cr), aluminum (Al), copper (Cu), niobium (Nb), or nickel (Ni). For example, the metallic magnetic powder  51  may be, but is not limited to, Fe—Si—Cr based amorphous metal. 
         [0049]    The metallic magnetic powder  51  may have a particle size of about 0.1 μm to about 30 μm, and may have more than two metallic magnetic powders with different average particle sizes. By mixing two metallic magnetic powders with different average particle sizes, the density may be increased so that high permeability can be secured and a deterioration in efficiency thereof due to core loss can be prevented even under high frequency and high current conditions. 
         [0050]    The metallic magnetic powder  51  may be dispersed in a thermosetting resin. The thermosetting resin may be, for example, epoxy resin, polyimide, or the like. 
         [0051]    The coil electronic component  100 , according to an example, includes the magnetic layer  62  that is formed on the magnetic body  50 . 
         [0052]    The magnetic layer  62  may be formed of a soft magnetic material with a high permeability and may be, for example, formed of a metal or an alloy that includes at least one of iron (Fe), silicon (Si), boron (B), chromium (Cr), aluminum (Al), copper (Cu), niobium (Nb), or nickel (Ni). Preferably, the magnetic layer  62  may be formed of Fe—Si or Fe—Ni. The magnetic layer  62  may be formed, for example, by performing an electroplating process on the magnetic body  50 , but is not limited to being formed by such a process. 
         [0053]    The magnetic layer  62  may be formed on the magnetic body  50  to increase the permeability of the coil electronic component  100  and to implement high inductance L and excellent quality factor Q. In addition, since the magnetic layer  62  surrounds surfaces of the magnetic body  50 , loss of magnetic flux can be prevented. 
         [0054]    As the miniaturization of the coil electronic component has been required along with the gradual miniaturization of the electronic devices, the volume of the magnetic material and the number of turns of the coil part decrease due to the miniaturization of the chip electronic component, thereby deteriorating the inductance and quality factor. 
         [0055]    Despite the conventional efforts to solve these problems through improving permeability by forming the magnetic body using a magnetic material having a high permeability, it has been difficult to achieve the target inductance and quality factor while decreasing the size of the chip electronic components due to limitations in developing materials having a high permeability. 
         [0056]    However, in the examples disclosed herein, by forming the magnetic layer  62  with high permeability on surfaces of the magnetic body  50 , the entire permeability of the coil electronic component  100  may be increased without increasing the permeability of the magnetic material that is included in the magnetic body  50 . 
         [0057]    The disclosed examples may implement high inductance L without increasing the number of turns of the coil part  40  by forming the magnetic layer  62 , increase the permeability of the coil electronic component  100 , and reduce the number of coil turns to increase volume of the magnetic material so that the quality factor Q may be increased. In addition, since the magnetic layer  62  surrounds surfaces of the magnetic body  50 , loss of magnetic flux can be prevented. 
         [0058]    A plating seed layer  61  may be formed between the surfaces of the magnetic body  50  and the magnetic layer  62 . The plating seed layer  61  works as a seed for electroplating to form the magnetic layer  62  on the magnetic body  50  and may include a material having excellent electrical conductivity, for example, copper (Cu). The plating seed layer  61  may be formed, for example, by a thin film process such as electroless plating, sputtering, or the like, but is not limited to being formed by such processes. 
         [0059]    As discussed above, the insulating cover layer  70  is formed on the magnetic layer  62 . The insulating cover layer  70  may include an insulating material such as epoxy resin. By forming the insulating cover layer  70 , a short-circuit defect due to the magnetic layer  62  can be prevented, and defects such as plating spread can be also prevented when forming a plating layer of external contacts  81  and  82 . 
         [0060]    The coil part  40  includes a first lead part  41 ′ that extends from one end portion of the first coil conductor  41  to the first end surface Su in the length direction X of the magnetic body  50 , and a second lead part  42 ′ extends from one end portion of the second coil conductor  42  to the second end surface S L2  in the length direction X of the magnetic body  50 . 
         [0061]    The first and second coil conductors  41  and  42  are surrounded by the insulating layer  30  to prevent the first and second coil conductors  41  and  42  from being contacted directly by the magnetic material (e.g., the magnetic powder  51  dispersed in the thermosetting resin) in the magnetic body  50 . 
         [0062]    The first and the second external contacts  81  and  82  are respectively arranged on the first and the second end surfaces S L1  and S L2  in the length direction X of the magnetic body  50 , and are respectively connected to the first and the second lead parts  41 ′ and  42 ′. 
         [0063]    Except for the first and second end surfaces S L1  and S L2  of the magnetic body  50 , the magnetic layer  62  may be formed on any surfaces of the magnetic body  50 . For example, the magnetic layer  62  may be formed on the first and the second side surfaces S W1  and S W2  in the width direction W and the first and the second main surfaces S T1  and S T2  in the thickness direction T. 
         [0064]    By not forming the magnetic layer  62  on the end surfaces S L1  and S L2  of the magnetic body  50 , a short-circuit defect can be prevented. In addition, the magnetic layer  62  is covered by the insulating cover layer  70  to prevent direct contact with the first and the second external contacts  81  and  82 . 
         [0065]      FIG. 3  is a cross-sectional view taken along line II-II′ of  FIG. 1   
         [0066]    Referring to FIG. 3 , the first and the second coil conductors  41  and  42  are connected through a via  46  that penetrates through the substrate  20 . The first and the second coil conductors  41  and  42  and the via  46  may be formed, for example, of a metal having excellent electrical conductivity, such as silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), copper (Cu), platinum (Pt) or an alloy thereof. 
         [0067]    The first coil conductor  41  and the second coil conductor  42  are coated with the insulating layer  30  to prevent direct contact with the magnetic material of the magnetic body  50  and to prevent a short-circuit defect. 
         [0068]    Manufacturing Method of Chip Electronic Component 
         [0069]      FIGS. 4 through 9  are views schematically describing an example manufacturing method of the chip electronic component  100 . 
         [0070]    Referring to  FIG. 4 , the coil part  40  is formed. 
         [0071]    After a via hole (not shown) is formed in the substrate  20  and a plating resist (not shown) having an opening is formed on the substrate  20 , the first and the second coil conductors  41  and  42  and the via  46  that connects the first and the second coil conductors  41  and  42  may be formed by filling the via hole and the opening with a conductive metal by a plating process. 
         [0072]    The first and the second coil conductors  41  and  42  and the via  46  may be formed, for example, of a metal having excellent electrical conductivity, such as silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), copper (Cu), platinum (Pt) or an alloy thereof. 
         [0073]    The method of forming the coil part  40  is not limited to the aforementioned plating process. The coil part  40  may, for example, be formed with a metallic wire or have any suitable shapes that can be formed inside of the magnetic body  50  and generate a magnetic flux by a current that is applied thereto. 
         [0074]    The insulating layer  30  is formed on the first and the second coil conductors  41  and  42  to coat the first and the second coil conductors  41  and  42 . 
         [0075]    The insulating layer  30  may be formed, for example, by a known method such as a screen printing method, an exposure and development method of a photoresist (PR), a spraying method, an oxidation method by chemical etching of coil conductor, or the like. 
         [0076]    A core hole  55 ′ may be formed by removing the central portion of the substrate  20 , in which the first and the second coil conductors  41  and  42  are not formed. The removal of the central portion of the substrate  20  may be performed by mechanical drilling, laser drilling, sand blasting, punching, or the like. 
         [0077]    Referring to  FIG. 5 , magnetic sheets  50 ′ containing the metallic magnetic powder  51  are manufactured. 
         [0078]    The magnetic sheets  50 ′ may be manufactured in a sheet shape by mixing the metallic magnetic powder  51 , a thermosetting resin, a binder, and a solvent to manufacture a slurry, applying the slurry to a carrier film to a thickness of several tens of μm by using a doctor blade, and then drying the applied slurry. 
         [0079]    The magnetic sheets  50 ′ contain the metallic magnetic powder  51  dispersed in the thermosetting resin such as epoxy resin, polyimide, or the like. 
         [0080]    The magnetic body  50  in which the coil part  40  is embedded is formed by stacking the magnetic sheets  50 ′ above and below the first and second coil conductors  41  and  42 , and then compressing and hardening the magnetic sheets  50 ′. 
         [0081]    Thereafter, the core hole  55 ′ is filled with the magnetic material to form the core part  55 . 
         [0082]    The method of forming the magnetic body  50  in which the coil part  40  is embedded is not be limited the aforementioned process, and any suitable method that is capable of forming a magnetic-resin compound in which the coil part  40  is embedded may be applied. 
         [0083]    Referring to  FIG. 6 , the plating seed layer  61  is formed on the surfaces of the magnetic body  50 . 
         [0084]    The plating seed layer  61  functions as a seed for electroplating to form the magnetic layer  62  on the magnetic body  50  and may include a material having excellent electrical conductivity, for example, copper (Cu). The plating seed layer  61  may be formed, by a thin film process such as electroless plating, sputtering, or the like, but is not limited to such processes. 
         [0085]    Referring to  FIG. 7 , the magnetic layer  62  is formed on the plating seed layer  61 . 
         [0086]    The magnetic layer  62  may be formed of a soft magnetic material with a high permeability and may be, for example, formed of a metal or an alloy that includes at least one of iron (Fe), silicon (Si), boron (B), chromium (Cr), aluminum (Al), niobium (Nb), or nickel (Ni). The magnetic layer  62  may be formed, for example, by performing an electroplating process on the magnetic body  50 , but is not limited to being formed by such a process. 
         [0087]    The magnetic layer  62  is formed on the magnetic body  50  to increase the permeability of the coil electronic component  100  and to implement high inductance L and excellent quality factor Q. In addition, since the magnetic layer  62  surrounds surfaces of the magnetic body  50 , loss of magnetic flux can be prevented. 
         [0088]    Referring to  FIG. 8 , portions of the plating seed layer  61  and the magnetic layer  62  that are formed on the end surfaces of the magnetic body  50 , to which the lead parts  41 ′ and  42 ′ of the coil part  40  extend, are removed. These portions of the plating seed layer  61  and the magnetic layer  62  may be removed, for example, by a chemical etching process. However, these portions of the plating seed layer  61  and the magnetic layer  62  may be removed by other processes. 
         [0089]    By removing the portions of plating seed layer  61  and the magnetic layer  62  that are formed on the end surfaces of the magnetic body  50 , a short-circuit defect can be prevented. 
         [0090]    Referring to  FIG. 9 , the insulating cover layer  70  is formed on the magnetic layer  62 . The insulating cover layer  70  may include an insulating material such as epoxy resin. By forming the insulating cover layer  70 , a short-circuit defect due to the magnetic layer  62  can be prevented, and defects such as plating spread can be also prevented when forming a plating layer of external contacts  81  and  82  ( FIG. 2 ). 
         [0091]    The first and the second external contacts  81  and  82  ( FIG. 2 ) are formed on the outer surfaces of the magnetic body  50  and are electrically connected to the lead parts  41 ′ and  42 ′ of the coil part  40 . 
         [0092]    While this disclosure includes specific examples, it will be apparent to one of ordinary skill in the art that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.