Patent Publication Number: US-11646146-B2

Title: Coil component

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims benefit of priority to Korean Patent Application No. 10-2019-0163946 filed on Dec. 10, 2019 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 coil component. 
     2. Description of Related Art 
     In accordance with the miniaturization and thinning of electronic devices such as a digital television (TV), a mobile phone, a laptop computer, and the like, miniaturization and thinning of coil components used in such electronic devices have been demanded. In order to satisfy such demand, research and development of various winding type or thin film type coil components have been actively conducted. 
     A main issue depending on the miniaturization and thinning of the coil component is to implement characteristics equal to characteristics of an existing coil component in spite of the miniaturization and thinning. In order to satisfy such demand, a ratio of a magnetic material should be increased in a core in which the magnetic material is filled. However, there is a limitation in increasing the ratio due to a change in strength of a body of an inductor, frequency characteristics depending on insulation properties of the body, and the like. 
     As an example of a method of manufacturing the coil component, a method of implementing the body by stacking and then pressing sheets in which magnetic particles, a resin, and the like, are mixed with each other on coils has been used. Fe-based alloys, or the like, have been used as an example of the magnetic particle to improve saturation magnetic flux density. 
     SUMMARY 
     An aspect of the present disclosure is to provide enhanced characteristics of a coil component including a magnetic metal powder. To this end, magnetic characteristics of the coil component are to be enhanced by improving a packing rate of the magnetic metal powder in a body. 
     According to an aspect of the present disclosure, a coil component may include a body comprising a support member and a coil portion embedded in one surface of the support member; and external electrodes connected to the coil portion, wherein the body contains a plurality of metal particles, at least some of the plurality metal particles containing a plastically deformable first particle, and at least some of the first particles have a deformed surface and thus have a shape corresponding to a surface of a neighboring magnetic metal particle. 
     In an exemplary embodiment, the first particle may contain a Fe-based crystalline material. 
     In an exemplary embodiment, the first particle may contain pure iron. 
     In an exemplary embodiment, the surface of the first particle may have a shape corresponding to a surface of a neighboring first particle due to its plastically deformable characteristic. 
     In an exemplary embodiment, the surface of the first particle may have a concave portion, and the surface of the neighboring first particle may have a convex portion in the form of being inserted into the concave portion. 
     In an exemplary embodiment, the plurality magnetic metal particles contain a second particle having a larger diameter than the first particle. 
     In an exemplary embodiment, the second particle may be formed of a material not plastically deformable. 
     In an exemplary embodiment, the second particle may contain a Fe-based amorphous alloy. 
     In an exemplary embodiment, the first particle may contain a Fe-based crystalline. 
     In an exemplary embodiment, at least some of the second particle may have a spherical shape, and the first particle neighboring the spherical second particle may have a shape corresponding to the surface of the spherical second particle. 
     In an exemplary embodiment, the first particle may have a particle size of 10 μm or less, and the second particle may have a particle size of 20 μm or above. 
     In an exemplary embodiment, the coil component may further include an insulating layer covering the surface of the coil portion. 
     In an exemplary embodiment, the insulating layer may have an integrated structure covering a side surface and an upper surface of the coil portion. 
     In an exemplary embodiment, the insulating layer may contain F-type parylene. 
     In an exemplary embodiment, the insulating layer may include a first layer covering the side and upper surfaces of the coil portion, and a second layer covering the first layer. 
     In an exemplary embodiment, the first layer may contain parylene, and the second layer may contain an epoxy resin. 
     In an exemplary embodiment, the insulating layer may include a first layer formed along the surface of the coil portion while covering the side and upper surfaces of the coil portion, and the second layer covering the first layer. 
     In an exemplary embodiment, the first layer is anatomic layer deposition (ALD) layer, and the second layer comprises parylene. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features, and 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 perspective view illustrating a coil component according to an exemplary embodiment in the present disclosure; 
         FIGS.  2  and  3    are cross-sectional views of the coil component of  FIG.  1    respectively taken along lines I-I′ and respectively; 
         FIGS.  4  and  5    are enlarged views illustrating a body region in the coil component of  FIG.  2   ; and 
         FIGS.  6  to  8    are diagrams schematically illustrating a coil portion employable in a modified coil portion and an insulating layer covering the same. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail. However, the present disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Accordingly, the shapes and dimensions of elements in the drawings may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
       FIG.  1    is a schematic perspective view illustrating a coil component according to an exemplary embodiment in the present disclosure, and  FIGS.  2  and  3    are cross-sectional views of the coil component of  FIG.  1    respectively taken along lines I-I′ and II-II′.  FIGS.  4  and  5    are enlarged views illustrating a body region in the coil component of  FIG.  2   . 
     Referring to  FIG.  1   , a coil component  100  according to an exemplary embodiment has a structure mainly including a body  101  embedded with a support member  102  and a coil portion  103 , and external electrodes  105  and  106 . As illustrated in  FIGS.  4  and  5   , the body  101  contains a plurality of magnetic metal particles, and at least some of the plurality of the magnetic metal particles contain plastically deformable first particles  111 . At least some of the first particles  111  have a deformed surface and thus have a shape corresponding to surfaces of neighboring magnetic metal particles. 
     The body  101  seals the support member  102 , the coil portion  103 , and the like, to protect the same, or may form an exterior of the coil component  100 . As illustrated in  FIG.  4   , the body  101  includes a plurality of magnetic metal particles. In this case, the body  101  may be in the form in which the magnetic metal particles are dispersed in an insulating body  110  formed of a resin, or the like. The insulating body  110  may be formed of a thermosetting resin, a thermoplastic resin, a wax-based material, an inorganic material, or the like. The magnetic metal particles  111  and  112  may contain a Fe-based alloy or pure Fe, which has excellent magnetic characteristics. As described above, the plurality of magnetic metal particles contain a first particle  111  which is plastically deformable. Further, as illustrated in  FIG.  4   , the plurality of magnetic metal particles include a second particle  112  having a larger diameter than the first particle  111 . In the case of the present exemplary embodiment, the body  101  can be molded under high pressure by forming the first particle  111  with a plastically deformable material. Accordingly, a packing rate of the first and second particles  111  and  112  may be improved in the body  101 . This will be described in more detail below. 
     Due to characteristics that the coil of the coil portion  103  expresses, the coil portion  103  plays various roles in an electronic device. For example, the coil portion  100  may be a power inductor, which is a case in which the coil portion  103  stores electricity in a magnetic field to maintain an output voltage, thereby stabilizing power. To this end, the coil portion  103  may have a spiral shape forming at least one turn and may be formed on at least one surface of the support member  102 . In the exemplary embodiment, the coil portion  103  is illustrated to include first and second coil patterns  103   a  and  103   b  disposed on two surfaces of the support member  102  opposing each other. In this case, the first and second coil patterns  103   a  and  103   b  may contain a pad region P and may be connected to each other via a via V penetrating the support member  102 . Such coil patterns  103   a  and  103   b  may be formed by a method used in the art such as a plating method, for example, pattern plating, anisotropic plating, isotropic plating, or the like, and may be formed to have a multilayer structure using a plurality of said methods. As illustrated in the drawings, the coil patterns  103   a  and  103   b  may have a core region C in a center region. A material forming the body  101  may be filled in the core region C of the coil pattern  103 . 
     A lead pattern L is disposed in an outermost region of the coil portion  103  to provide a connection path with the external electrodes  105  and  106  and may be integrally formed with the coil portion  103 . In this case, as illustrated in the drawings, the lead pattern L may have a larger width than the coil pattern  103  to be connected to the external electrodes  105  and  106 . As used herein, the term “width” refers to a width in an X direction based on  FIG.  1   . 
     The support member  102  supporting the coil portion  103  may be formed of a polypropylene glycol (PPG) substrate, a ferrite substrate, a metal-based soft magnetic substrate, or the like. In this case, a through-hole may be formed in a center region of the support member  102 , and a magnetic material may be filled in the through-hole to form a core region C. The core region C constitutes a portion of the body  101 . As described above, the core region C filled with the magnetic material may be formed to improve performance of the coil component  100 . 
     The external electrodes  105  and  106  may be formed outside of the sealing member  101  to be connected to the lead pattern L. The external electrodes  105  and  106  may be formed of a paste containing a metal having excellent electrical conductivity, for example, a conductive paste containing nickel (Ni), copper (Cu), tin (Sn), silver (Ag), or alloys thereof. In addition, a plating layer may be further formed on the external electrodes  105  and  106 . In this case, the plating layer may contain at least one selected from the group consisting of nickel (Ni), copper (Cu) and tin (Sn); for example, a nickel (Ni) layers and a tin (Sn) layer may be sequentially formed. 
     As previously described, the magnetic metal particles  111  and  112  contain the first and second particles  111  and  112 , and a particle size of the first particle  111  is larger than that of the second particle  112 . A packing rate of the magnetic metal particles  111  and  112  in the body  101  can be improved by employing the first particle  111  plastically deformable and having a relatively small particle size. The first particle may have a particle size of 10 μm or less, and the second particle may have a particle size of 20 μm or above. The particle size can be measured by a method optical microscopy, sieving, sedimentation or particle volume measurement, which is appreciated by the one skilled in the art. 
     The first particle  111  is a plastically deformable metal particle and contains, for example, a Fe-based crystalline material. Specifically, the first particle  111  may contain pure iron, for example, carbonyl iron powder (CIP). When the body  101  is formed by high pressure molding, at least a portion of the first particle  111  is plastically deformed, and accordingly, a surface thereof may have a shape corresponding to a surface of a neighboring first particle  111 . As used herein, the expression “shape corresponding to a surface” of another particle refers to a shape of at least a portion of the surface of the first particle  111 , modified to be similar or substantially identical to a surface of a neighboring first particle  111 . As an example of such a form, the surface of the first particle  111  includes a concave portion P 1 , and the surface of the neighboring first particle has a convex portion P 2  in the form of being inserted into the concave portion P 1  as shown in  FIG.  4   . In this case, the first particle  111  may be in contact with the neighboring first particle  111 , or an insulating body  110 , or the like, may be disposed therebetween without the first particle and the neighboring first particle being in contact with each other. As the first particle  111  is plastically deformed and thus has the previously described surface, a packing rate of the magnetic metal particles  111  and  112  may increase. As used herein, the term “packing rate” may be defined as a volume accounted for by the magnetic metal particles  111  and  112  in the body  101 . 
     The second particle  112  is a larger particle size, compared to the first particle  111 . Use of particles having different diameter distributions facilitates the packing rate of the magnetic metal particles  111  and  112  to increase in the body  101  compared to when a single type of a particle is used. In contrast to the first particle  111 , the second particle  112  may be a material which is not plastically deformed. To this end, the second particle  112  may contain a Fe-based amorphous alloy. Specifically, the second particle  112  may contain at least one selected from the group consisting of Fe, Si, Cr, B and Ni; for example, the second particle  112  may be an amorphous Fe—Si—B—Cr metal, but is not necessarily limited thereto. As a more specific example, the magnetic metal particle  111  a d  112  may be formed of a Fe—Si—B—Nb—Cr alloy, a Fe—Ni alloy, or the like. As used herein, the expression “second particle  112  not plastically deformed” refers to having a lower plastic deformability than the first particle, when the expression does not mean that no plastic deformation occurs at all, but is rather considered that there is barely a plastic deformation and thus has substantially no plastic deformation. 
     At least some of the second particle  112  having low plastic deformability maintains a spherical shape as illustrated in the drawings. The first particles  111  adjacent to the spherical second particle  112  may have a shape corresponding to a surface thereof. That is, the first particle  111  neighboring the second particle  112  may have a surface whose portion is concave. A surface of the concaved region may be a portion of the spherical shape. 
     Although  FIG.  4    illustrates the shape in which the first and second particles  111  and  112  have different particle size distributions, three types of particles having different particle size distributions may be employed. Alternatively, a single type of particle can be used, which is illustrated in  FIG.  5   . In this case, only the first particle  111 , which is plastically deformable, is contained in the body  101 , and the first particle  111  may have a surface shape corresponding to a neighboring first particle  111  due to high pressure molding. 
     Meanwhile, when the body  101  is subject to high pressure molding, an insulating structure is required to insulate the coil portion  103  from the magnetic metal particles  111  and  112 . As illustrated in  FIGS.  6  to  8   , an insulating layer covering the coil portion  103  may be employed. In the present disclosure, mechanical stability and insulating performance of the coil portion  103  are to be improved by employing a material and a shape of such an insulating layer appropriate for high pressure molding. 
     In an embodiment depicted in  FIG.  6   , the insulating layer  120  covers a surface of the coil portion  103 ; specifically, the insulating layer  120  may be integrally formed to cover side and upper surfaces of the coil portion  103 . The insulating layer  120  may contain an F-type parylene. Compared to N-type parylene, the F-type parylene has excellent tensile and yield strength, thereby allowing the insulating layer  120  to more effectively protect the coil portion  103 . Parylene is a group of polymers having a p-xylene structure. Parylene includes various types such as N-type, C-type, D-type, F-VT4-type and F-AT 4-type. 
     In an embodiment depicted in  FIG.  7   , the insulating layer includes a bilayer structure; specifically, a first layer  121  covers the side and upper surfaces of the coil portion  103  while a second layer  122  covers the first layer  121 . Contrary to  FIG.  6   , parylene included in the insulating layer does not need to be limited to a particular type and thus the first layer  121  may contain parylene other than F-type parylene because the insulating layer has an additional insulating structure as the second layer  122 . The second layer  122  contains an epoxy resin. The epoxy resin contained in the second layer  122  is advantageous for various types of precursors and composition designs. Besides, the epoxy resin has excellent adhesion and thus can serve to implement a more stable insulating structure. 
       FIG.  8    illustrates an insulating layer having a bilayer structure; specifically, a first layer  123  covers the side and upper surfaces of the coil portion  103  formed along a surface of the coil portion while a second layer  124  covers the first layer  123 . The first layer  123  may be a layer formed by an atomic layer deposition (ALD) (an ALD layer) and may contain a ceramic material such as, for example, Al 2 O 3 , TiO 2 , ZrO 2 , or the like. The ALD layer may have a small thickness of several hundred nanometers, and accordingly, the first layer  123  may have a shape corresponding the surface structure of the coil portion  103 . Such ALD layer has excellent insulating characteristics and strength despite the small thickness and may thus have a stable insulating structure. The second layer  124  may contain parylene or another material such as an epoxy resin. 
     As set forth above, in the coil component according to an exemplary embodiment in the present disclosure, a packing rate of a magnetic metal powder is improved in a body, thereby enhancing the characteristics such as inductance, or the like. 
     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 invention as defined by the appended claims.