Patent Publication Number: US-11398341-B2

Title: Electronic component

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of priority to Japanese Patent Application 2016-098192 filed May 16, 2016, and to International Patent Application No. PCT/JP2017/000045 filed Jan. 4, 2017, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an electronic component. 
     Background Art 
     A conventional coil component is described as an example of an electronic component in Japanese Laid-Open Patent Publication No. 2014-197590. This electronic component has a substrate, a first conductor layer disposed on an upper surface of the substrate, a first insulating layer disposed on the first conductor layer, a second conductor layer disposed on a lower surface of the substrate, and a second insulating layer disposed under the second conductor layer. A first external electrode and a second external electrode are disposed on the first insulating layer. The first external electrode is electrically connected through a first lead-out electrode to the first conductor layer. The second external electrode is electrically connected through a second lead-out electrode to the second conductor layer. 
     SUMMARY 
     The conventional coil component is provided with conductor layers on both sides of the substrate; however, to reduce the height etc., for example, it is conceivable that multiple conductor layers and multiple insulating layers are alternately disposed on the substrate to achieve a configuration (built-up configuration) in which the conductor layers are connected through via electrodes. In this case, the insulating layers between the conductor layers have a thermal expansion coefficient higher than the conductor layers, so that interlayer peeling may occur between the conductor layers, for example, at an interface between the conductor layers and the via electrodes, due to a difference in thermal expansion coefficient caused by heat. 
     Therefore, the present disclosure provides an electronic component capable of reducing interlayer peeling between conductor layers. 
     In particular, the present disclosure provides an electronic component comprising a main body part including an insulating layer and a conductor layer laminated alternately. The insulating layer and the conductor layer are partially exposed on a side surface of the main body part in a direction orthogonal to a lamination direction. Also, the side surface of the main body part is provided with a metal film extending in the lamination direction to cover the insulating layer and the conductor layer exposed on the side surface. 
     The exposure includes not only exposure of the electronic component to the outside, but also exposure to another member, i.e., exposure at an interface with another member. The covering includes at least partially covering a member. 
     According to the electronic component, the metal film extends in the lamination direction of the insulating layer and the conductor layer and covers the insulating layer and the conductor layer on the side surface of the main body part, so that the metal film restrains the insulating layer and the conductor layer from moving in the lamination direction. Therefore, even when heat is applied to the electronic component, interlayer peeling between the conductor layers due to a difference in thermal expansion coefficient between the insulating layer and the conductor layer can be reduced. 
     In one embodiment of the electronic component, the electronic component has an external electrode disposed on one surface of the main body part in the lamination direction and electrically connected to the conductor layer, and the metal film is connected to the external electrode. According to the embodiment, since the metal film is connected to the external electrode and covers the insulating layer and the conductor layer on the side surface of the main body part, the metal film electrically bypasses the external electrode and the conductor layer. Therefore, electric resistance (particularly, DC electric resistance Rdc) can be reduced between the external electrode and the conductor layer. 
     In one embodiment of the electronic component, the main body part has a columnar electrode located between the external electrode and the conductor layer and electrically connecting the external electrode and the conductor layer. The columnar electrode is partially exposed on the side surface and the one surface of the main body part, and the metal film covers the columnar electrode exposed on the side surface. 
     According to the embodiment, the columnar electrode is partially exposed on the side surface and the one surface of the main body part, and the metal film covers the columnar electrode exposed on the side surface and the one surface. At the time of dicing on the side surface (cut surface) of the main body part in a manufacturing process of the electronic component, a load becomes larger when the columnar electrode is cut on the side surface of the main body part. When the load applied to the columnar electrode becomes larger, the columnar electrode may peel from the conductor layer, and the interlayer electric resistance may increase. However, the metal film covering the columnar electrode can reduce the interlayer electric resistance while reinforcing the columnar electrode against the peeling. 
     In one embodiment of the electronic component, the main body part has a via electrode embedded in the insulating layer and electrically connected to the conductor layer. The via electrode is partially exposed on the side surface of the main body part, and the metal film covers the via electrode exposed on the side surface. 
     According to the embodiment, the via electrode is partially exposed on the side surface of the main body part, and the metal film covers the via electrode exposed on the side surface. As a result, a portion of the via electrode and the metal film are connected, and the interlayer peeling due to heat can be reduced between the conductor layer and the via electrode. Particularly, even when the electronic component is reduced in size and the via electrode becomes smaller, the peeling can effectively be reduced. 
     In one embodiment of the electronic component, a width of the via electrode on one side in the lamination direction is smaller than a width of the via electrode on the other side in the lamination direction. According to the embodiment, a width of the via electrode on one side in the lamination direction is smaller than a width of the via electrode on the other side in the lamination direction. In this case, the interlayer peeling tends to occur on a connection surface with the conductor layer on the one side of the via electrode, so that the effect of the metal film reducing the interlayer peeling becomes more effective. 
     In one embodiment of the electronic component, the conductor layer is one of a plurality of conductor layers exposed on the side surface and arranged in the lamination direction. The main body part has a via electrode connecting the conductor layers adjacent to each other in the lamination direction, and the metal film connects the conductor layers adjacent to each other in the lamination direction. 
     According to the embodiment, since the via electrode is usually smaller and makes an area of a connection surface smaller between the conductor layer and the via electrode, the interlayer peeling tends to occur on the connection surface due to thermal expansion of the insulating layer; however, the metal film connects the conductor layers adjacent to each other in the lamination direction and therefore can reduce the interlayer peeling between the conductor layer and the via electrode due to heat. 
     In one embodiment of the electronic component, the conductor layers exposed on the side surface are three or more layers arranged in the lamination direction. According to the embodiment, when the conductor layers are three or more layers, the interlayer peeling is more likely to occur; however, the metal film makes the effect of reducing the interlayer peeling more effective. 
     In one embodiment of the electronic component, the external electrode is one of a plurality of external electrode arranged in parallel on the one surface of the main body part, the metal film is one of a plurality of metal films arranged in parallel on the side surface of the main body part, and the external electrodes are respectively connected to the metal films. According to the embodiment, the external electrode is one of a plurality of external electrode arranged in parallel on the one surface of the main body part, the metal film is one of a plurality of metal films arranged in parallel on the side surface of the main body part, and the external electrodes are respectively connected to the metal films. Such an increase in the numbers of the external electrodes and the metal films makes the connection surface of the conductor layer with the other member smaller due to restriction on the size of the electronic component so that the interlayer peeling is more likely to occur, and therefore, the effect of the metal layer reducing the interlayer peeling becomes more effective. 
     In one embodiment of the electronic component, the conductor layer constitutes a spiral wiring. According to the above embodiment, since the conductor layer constitutes a wiring with a narrow width, the connection surface of the conductor layer with the other member tends to be small so that the interlayer peeling is more likely to occur, and therefore, the effect of the metal layer reducing the interlayer peeling becomes more effective. 
     According to the electronic component of the aspect, since the side surface of the main body part is provided with the metal film extending in the lamination direction to cover the insulating layer and the conductor layer exposed on the side surface, the interlayer peeling of the conductor layer can be reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of an electronic component; 
         FIG. 2  is an XZ cross-sectional view of the electronic component; 
         FIG. 3A  is an explanatory view for explaining a method of manufacturing the electronic component; 
         FIG. 3B  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3C  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3D  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3E  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3F  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3G  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3H  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3I  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3J  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 3K  is an explanatory view for explaining the method of manufacturing the electronic component; 
         FIG. 4  is a view on X-direction arrow of a second embodiment of an electronic component; 
         FIG. 5  is a perspective view of a third embodiment of an electronic component; 
         FIG. 6A  is a graph of a relationship between the number of times of reflow and electric resistance in an example; and 
         FIG. 6B  is a graph of a relationship between the number of times of reflow and electric resistance in a comparative example. 
     
    
    
     DETAILED DESCRIPTION 
     An aspect of the present disclosure will now be described in detail with reference to shown embodiments. 
     First Embodiment 
       FIG. 1  is a perspective view of a first embodiment of an electronic component.  FIG. 2  is an XZ cross-sectional view of the electronic component.  FIGS. 1 and 2  show a coil component  1  as an example of an electronic component. The coil component  1  is mounted on an electronic device such as a personal computer, a DVD player, a digital camera, a TV, a portable telephone, and automotive electronics, for example, and is a component generally having a rectangular parallelepiped shape, for example. However, the shape of the coil component  1  is not particularly limited and may be a circular columnar shape, a polygonal columnar shape, a truncated cone shape, or a truncated polygonal pyramid shape. 
     As shown in  FIGS. 1 and 2 , the coil component  1  has a main body part  10  including insulating layers  41 ,  42 ,  43  and conductor layers  201 ,  202  laminated alternately, and external electrodes  61 ,  62  disposed on one surface  103  in a lamination direction of the main body part  10  and electrically connected to the conductor layers  201 ,  202 . The lamination direction is a stacking direction (Z direction), rather than an extending direction (XY direction), of the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202 . Therefore, the first insulating layer  41 , the first conductor layer  201 , the second insulating layer  42 , the second conductor layer  202 , and the third insulating layer  43  are laminated in order in the lamination direction. 
     The insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  are partially exposed on side surfaces  101 ,  102  in a direction orthogonal to the lamination direction of the main body part  10 . Metal films  80  are disposed on the side surfaces  101 ,  102  of the main body part  10 . The metal films  80  are connected to the external electrodes  61 ,  62  and extend in the lamination direction to cover the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  exposed on the side surfaces  101 ,  102 . In  FIG. 1 , for clarification, the external electrodes  61 ,  62  are not shown, and the metal films  80  are drawn by dashed-two dotted lines. 
     Therefore, the metal films  80  extend in the lamination direction of the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  and cover the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  on the side surfaces  101 ,  102  of the main body part  10 , so that the metal films  80  restrain the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  from moving in the lamination direction. Therefore, even when heat is applied to the coil component  1 , interlayer peeling of the conductor layers  201 ,  202  due to a difference in thermal expansion coefficient of the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  can be reduced. If a conductive resin containing a metal powder is used instead of the metal film  80 , the conductive resin has a thermal expansion coefficient close to that of the insulating layers  41 ,  42 ,  43  and cannot restrain the expansion and contraction of the insulating layers  41 ,  42 ,  43 , so that the effect of reducing the interlayer peeling cannot be obtained. 
     Since the metal films  80  are connected to the external electrodes  61 ,  62  and cover the insulating layers  41 ,  42 ,  43  and the conductor layers  201 ,  202  on the side surfaces  101 ,  102  of the main body part  10 , the metal films  80  electrically bypass the external electrodes  61 ,  62  and the conductor layers  201 ,  202 . Therefore, electric resistance (particularly, DC electric resistance Rdc) can be reduced between the external electrodes  61 ,  62  and the conductor layers  201 ,  202 . 
     Furthermore, when the external electrodes  61 ,  62  of the coil component  1  are mounted on a mounting substrate via solder, the solder wets up along the metal film  80  in the direction away from the external electrodes  61 ,  62  in the lamination direction into a fillet shape, so that the strength of the coil component  1  is improved. Therefore, the reliability of the solder connection is improved, and cracks etc. are restrained from occurring in the solder due to heat of reflow, for example. 
     In the coil component  1 , the main body part  10  has columnar electrodes  11 ,  12  located between the external electrodes  61 ,  62  and the conductor layers  201 ,  202  and electrically connecting the external electrodes  61 ,  62  and the conductor layers  201 ,  202 . The columnar electrodes  11 ,  12  are partially exposed on the side surfaces  101 ,  102  and the one surface  103  of the main body part  10 , and the metal films  80  cover the columnar electrodes  11 ,  12  exposed on the side surfaces  101 ,  102 . 
     At the time of dicing on the side surfaces  101 ,  102  (cut surfaces) of the main body part  10  in a manufacturing process of the coil component  1 , a load becomes larger when the columnar electrodes  11 ,  12  are cut on the side surfaces  101 ,  102  of the main body part  10 . When the load applied to the columnar electrodes  11 ,  12  becomes larger, the columnar electrodes  11 ,  12  may peel from the conductor layers  201 ,  202 , and the interlayer electric resistance may increase. However, the metal films  80  covering the columnar electrodes  11 ,  12  can reduce the interlayer electric resistance while reinforcing the columnar electrodes  11 ,  12  against the peeling. 
     In the coil component  1 , the main body part  10  has via electrodes  271 ,  272 ,  273  embedded in the insulating layers  42 ,  43  and electrically connecting the conductor layers  201 ,  202 . The via electrodes  271 ,  272  are partially exposed on the side surfaces  101 ,  102  of the main body part  10 , and the metal films  80  cover the via electrodes  271 ,  272  exposed on the side surfaces  101 ,  102 . 
     As a result, the via electrodes  271 ,  272  are connected to the metal films  80 , and the interlayer peeling due to heat can be reduced between the conductor layers  201 ,  202  and the via electrodes  271 ,  272 . Particularly, even when the coil component  1  is reduced in size and the via electrodes  271 ,  272  become smaller, the peeling can effectively be reduced. 
     The coil component  1  will hereinafter be described in detail. 
     As shown in  FIGS. 1 and 2 , the coil component  1  has the main body part  10 , the first external electrode  61  and the second external electrode  62  disposed on the one surface  103  of the main body part  10 , the metal films  80  disposed on the first side surface  101  and the second side surface  102  of the main body part  10 , and the first columnar electrode  11  and the second columnar electrode  12  disposed in the main body part  10  and connected to the first external electrode  61  and the second external electrode  62 , respectively. 
     The main body part  10  is formed in a substantially rectangular parallelepiped shape and has a length, a width, and a height. The length direction of the main body part  10 , the width direction of the main body part  10 , and the height direction of the main body part  10  are defined as an X direction, a Y direction, and a Z direction, respectively. The first side surface  101  and the second side surface  102  are arranged in the X direction. 
     The main body part  10  has the first conductor layer  201  and the second conductor layer  202 , an insulator  40  covering the first and second conductor layers  201 ,  202 , and a magnetic body  30  covering the insulator  40 . The insulator  40  is made up of the first insulating layer  41 , the second insulating layer  42 , and the third insulating layer  43 . The first insulating layer  41 , the first conductor layer  201 , the second insulating layer  42 , the second conductor layer  202 , and the third insulating layer  43  are laminated in order from the lower layer to the upper layer. In this description, the upper and lower sides of the coil component  1  are described as being coincident with the upper and lower sides (in the Z direction) on the plane of  FIG. 1 . The Z direction coincides with the stacking direction of the layers (lamination direction). 
     The first conductor layer  201  includes a first spiral wiring  21 . The second conductive layer  202  includes a second spiral wiring  22 . The first and second spiral wirings  21 ,  22  are each formed into a spiral shape in a plane. For example, the first spiral wiring  21  is formed in a spiral shape turning clockwise and approaching the center when viewed from above. For example, the second spiral wiring  22  is formed in a spiral shape turning clockwise away from the center when viewed from above. 
     The first and second spiral wirings  21 ,  22  are made of low-resistance metal such as Cu, Ag, and Au, for example. Preferably, low-resistance and narrow-pitch spiral wirings can be formed by using Cu plating formed by a semi-additive method. 
     The first spiral wiring  21  is laminated on the first insulating layer  41 . The second insulating layer  42  is laminated on the first insulating layer  41  to cover the first spiral wiring  21 . The second spiral wiring  22  is laminated on the second insulating layer  42 . The third insulating layer  43  is laminated on the second insulating layer  42  to cover the second spiral wiring  22 . In this way, the first and second spiral wirings  21 ,  22  and the first to third insulating layers  41 ,  42 ,  43  are alternately laminated. In other words, the first and second spiral wirings  21 ,  22  are each laminated on an insulating layer and covered with an insulating layer upper than the insulating layer. 
     The second spiral wiring  22  is electrically connected to the first spiral wiring  21  through the third via electrode  273  extending in the lamination direction on the inner circumferential side. The third via electrode  273  is disposed in the second insulating layer  42 . An inner circumferential portion  21   a  of the first spiral wiring  21  and an inner circumferential portion  22   a  of the second spiral wiring  22  are electrically connected through the third via electrode  273 . As a result, the first spiral wiring  21  and the second spiral wiring  22  constitute one inductor. 
     An outer circumferential portion  21   b  of the first spiral wiring  21  and an outer circumferential portion  22   b  of the second spiral wiring  22  are located at both end sides of the insulator  40  when viewed in the lamination direction. The outer circumferential portion  21   b  of the first spiral wiring  21  is located on the first columnar electrode  11  side, and the outer circumferential portion  22   b  of the second spiral wiring  22  is located on the second columnar electrode  12  side. 
     The outer circumferential portion  21   b  of the first spiral wiring  21  is electrically connected to the first columnar electrode  11  through the second via electrode  272  on the outer circumferential side disposed in the second insulating layer  42 , a first connection wiring  25  disposed on the second insulating layer  42 , and the first via electrode  271  on the outer circumferential side disposed in the third insulating layer  43 . 
     The outer circumferential portion  22   b  of the second spiral wiring  22  is electrically connected to the second columnar electrode  12  through the first via electrode  271  disposed in the third insulating layer  43 . Although the outer circumferential portion  22   b  of the second spiral wiring  22  is also electrically connected to a second connection wiring  26  disposed on the first insulating layer  41  through the second via electrode  272  disposed in the second insulating layer  42 , this configuration is not essential. However, by disposing and connecting the second connection wiring  26  to the outer circumferential portion  22   b , the symmetric property in the coil component  1  can be improved to reduce variations in electrical characteristics and reliability. 
     The second connection wiring  26  and the first spiral wiring  21  constitute the first conductor layer  201 , and the first connection wiring  25  and the second spiral wiring  22  constitute the second conductor layer  202 . However, in the first conductor layer  201 , the second connection wiring  26  and the first spiral wiring  21  are not electrically connected, and in the second conductor layer  202 , the first connection wiring  25  and the second spiral wiring  22  are not electrically connected. 
     The insulator  40  is made of a composite material of an inorganic filler and a resin. The resin is an organic insulating material made of epoxy-based resin, bismaleimide, liquid crystal polymer, or polyimide, for example. The inorganic filler is an insulating layer of SiO 2  etc. The insulator  40  is not limited to the composite material and may be made only of a resin. The thermal expansion coefficient of the insulator  40  (the first, second, and third insulating layers  41 ,  42 ,  43 ) is usually 30 ppm/k or more, and also in this case, the interlayer peeling can effectively be reduced by the metal film  80 . The insulator  40  has an inner diameter hole portion  40   a  inside the inner diameters of the first and second spiral wirings  21 ,  22 . 
     The magnetic body  30  is made of a composite material of a resin  35  and a metal magnetic powder  36 . The resin  35  is an organic insulating material made of epoxy-based resin, bismaleimide, liquid crystal polymer, or polyimide, for example. The metal magnetic powder  36  is, for example, an FeSi alloy such as FeSiCr, an FeCo alloy, an Fe alloy such as NiFe, or an amorphous alloy thereof. 
     The magnetic body  30  has an inner magnetic path  37   a  and an outer magnetic path  37   b . The inner magnetic path  37   a  is located in the inner diameters of the first and second spiral wirings  21 ,  22  and the inner diameter hole portion  40   a  of the insulator  40 . The outer magnetic path  37   b  is located above and below the first and second spiral wirings  21 ,  22  and the insulator  40  and is also located on the outer diameter side of the insulator  40  (not shown). 
     The first and second columnar electrodes  11 ,  12  are disposed above the first and second spiral wirings  21 ,  22  in the lamination direction. The first columnar electrode  11  is located on the first side surface  101  side of the main body part  10 . The second columnar electrode  12  is located on the second side surface  102  side of the main body part  10 . The columnar electrodes  11 ,  12  are made of the same material as the spiral wirings  21 ,  22 , for example. 
     The first columnar electrode  11  is embedded in the magnetic body  30  of the main body part  10  such that the first columnar electrode  11  is partially exposed on the first side surface  101  and the one surface  103  of the main body part  10 . The second columnar electrode  12  is embedded in the magnetic body  30  of the main body part  10  such that the second columnar electrode  12  is partially exposed on the second side surface  102  and the one face  103  of the main body part  10 . 
     The first columnar electrode  11  is electrically connected to the first spiral wiring  21 , and the second columnar electrode  12  is electrically connected to the second spiral wiring  22 . The first external electrode  61  is disposed on an upper surface of the first columnar electrode  11 , and the second external electrode  62  is disposed on an upper surface of the second columnar electrode  12 . When the coil component  1  is mounted on a mounting substrate, the first and second external electrodes  61 ,  62  are connected to electrodes of the mounting substrate via solder. 
     On the first side surface  101  of the main body part  10 , the metal film  80  is in contact with the first columnar electrode  11 , the first via electrode  271 , the first connection wiring  25 , the second via electrode  272 , and the outer circumferential portion  21   b  of the first spiral wiring  21  and is also in contact with the first external electrode  61 . The metal film  80  is made of low-resistance metal such as Cu, Ag, and Au, for example. The metal film  80  is formed by electrolytic plating, electroless plating, or sputtering, for example. 
     Similarly, on the second side surface  102  of the main body part  10 , the metal film  80  is in contact with the second columnar electrode  12 , the first via electrode  271 , the outer circumferential portion  22   b  of the second spiral wiring  22 , the second via electrode  272 , and the second connection wiring  26 , and is also in contact with the second external electrode  62 . 
     A method of manufacturing the coil component  1  will be described with reference to  FIGS. 3A to 3K . 
     As shown in  FIG. 3A , a base  50  is prepared. In this embodiment, a plurality of the coil components  1  is manufactured from the one base  50 . The base  50  has an insulating substrate  51  and base metal layers  52  disposed on both sides of the insulating substrate  51 . In this embodiment, the insulating substrate  51  is a glass epoxy substrate, and the base metal layers  52  are Cu foils having upper surfaces that are smooth surfaces. Since the thickness of the base  50  does not affect the thickness of the coil component  1  because the base  50  is peeled off as described later, the base with easy-to-handle thickness may be used as needed for the reason of warpage due to processing etc. 
     As shown in  FIG. 3B , a dummy metal layer  60  is bonded onto a surface of the base  50 . In this embodiment, the dummy metal layer  60  is a Cu foil. Since the dummy metal layer  60  is bonded to the base metal layer  52  of the base  50 , the dummy metal layer  60  is bonded to the smooth surface of the base metal layer  52 . Therefore, an adhesion force can be made weak between the dummy metal layer  60  and the base metal layer  52  and, at a subsequent step, the base  50  can easily be peeled from the dummy metal layer  60 . Preferably, an adhesive bonding the base  50  and the dummy metal layer  60  is an adhesive with low tackiness. For weakening of the adhesion force between the base  50  and the dummy metal layer  60 , it is desirable that the bonding surfaces of the base  50  and the dummy metal layer  60  are glossy surfaces. 
     Subsequently, the first insulating layer  41  is laminated on the dummy metal layer  60  temporarily bonded to the base  50 . In this case, the first insulating layer  41  is thermally press-bonded and thermally cured by a vacuum laminator, a press machine, etc. Subsequently, a central portion of the first insulating layer  41  corresponding to the inner magnetic path (magnetic core) is removed by a laser etc. to form an opening portion  41   a.    
     As shown in  FIG. 3C , the first spiral wiring  21  and the second connection wiring  26  are laminated as the first conductor layer  201  on the first insulating layer  41  by a semi-additive method. The first spiral wiring  21  and the second connection wiring  26  are formed not to be in contact with each other. The second connection wiring  26  is disposed on the side opposite to the outer circumferential portion  21   b . Specifically, first, a power feeding film is formed on the first insulating layer  41  by electroless plating, sputtering, vapor deposition, etc. After the formation of the power feeding film, a photosensitive resist is applied or affixed onto the power feeding film, and a wiring pattern is formed by photolithography. Subsequently, a metal wiring corresponding to the first spiral wiring  21  and the second connection wiring  26  is formed by the electrolytic plating. After the formation of the metal wiring, the photosensitive resist is peeled and removed by a chemical liquid, and the power feeding film is etched and removed. It is noted that this metal wiring can subsequently be used as a power feeding part to acquire the wirings  21 ,  26  with narrower spaces by performing additional Cu electrolytic plating. A first sacrificial conductor  71  corresponding to the inner magnetic path is disposed by using the semi-additive method on the dummy metal layer  60  in the opening portion  41   a  of the first insulating layer  41 . 
     As shown in  FIG. 3D , the second insulating layer  42  is laminated on the first insulating layer  41  to cover the first spiral wiring  21 , the second connection wiring  26 , and the first sacrificial conductor  71  with the second insulating layer  42 . The second insulating layer  42  is then thermally press-bonded and thermally cured by a vacuum laminator, a press machine, etc. 
     As shown in  FIG. 3E , a via hole  42   b  for filling the second via electrode  272  and the third via electrode  273  is formed in the second insulating layer  42  by laser processing etc. A portion of the second insulating layer  42  corresponding to the inner magnetic path (magnetic core) is removed by a laser etc. to form an opening portion  42   a.    
     As shown in  FIG. 3F , the second via electrode  272  and the third via electrode  273  are filled in the via hole, and the second spiral wiring  22  and the first connection wiring  25  are laminated on the second insulating layer  42  as the second conductor layer  202 . The second spiral wiring  22  and the first connection wiring  25  are formed not to be in contact with each other. The first connection wiring  25  is disposed on the side opposite to the outer circumferential portion  22   b . A second sacrificial conductor  72  corresponding to the inner magnetic path is disposed on the first sacrificial conductor  71  in the opening portion  42   a  of the second insulating layer  42 . In this case, the second via electrode  272 , the third via electrode  273 , the second spiral wiring  22 , the first connection wiring  25 , and the second sacrificial conductor  72  can be disposed by the same process as the first spiral wiring  21 , the second connection wiring  26 , and the first sacrificial conductor  71 . 
     As shown in  FIG. 3G , the third insulating layer  43  is laminated on the second insulating layer  42  to cover the second spiral wiring  22 , the first connection wiring  25 , and the second sacrificial conductor  72  with the third insulating layer  43 . The third insulating layer  43  is thermally press-bonded and thermally cured by a vacuum laminator, a press machine, etc. 
     As shown in  FIG. 3H , a portion of the third insulating layer  43  corresponding to the inner magnetic path (magnetic core) is removed by a laser etc. to form an opening portion  43   a.    
     Subsequently, the base  50  is peeled off from the dummy metal layer  60  on the bonding plane between the surface of the base  50  (the base metal layer  52 ) and the dummy metal layer  60 . The dummy metal layer  60  is removed by etching etc. In this process, the first and second sacrificial conductors  71 ,  72  are removed by etching etc., and as shown in  FIG. 3I , the inner diameter hole portion  40   a  corresponding to the inner magnetic path is disposed in the insulator  40 . Subsequently, a via hole  43   b  for filling the first via electrode  271  is formed in the third insulating layer  43  by laser processing etc. The first via electrode  271  is filled in the via hole  43   b , and the first and second columnar electrodes  11 ,  12  having a columnar shape are laminated on the third insulating layer  43 . In this case, the first via electrode  271  and the first and second columnar electrodes  11 ,  12  can be disposed by the same process as the first spiral wiring  21 . 
     As shown in  FIG. 3J , the first and second columnar electrodes  11 ,  12  as well as the upper and lower surface sides of the insulator  40  are covered with the magnetic body  30  and the magnetic body  30  is thermally press-bonded and thermally cured by a vacuum laminator, a press machine, etc. to form a coil substrate  5 . In this case, the magnetic body  30  is also filled into the hole portion  40   a  of the insulator  40 . 
     As shown in  FIG. 3K , the magnetic body  30  on the upper and lower sides of the coil substrate  5  is reduced in thickness by a grinding method. In this case, the first and second columnar electrodes  11 ,  12  are partially exposed so that the upper end surfaces of the first and second columnar electrodes  11 ,  12  are located on the same plane as the upper end surface of the magnetic body  30 . The first and second external terminals  61 ,  62  (see  FIG. 2 ) are then disposed on the upper end surfaces of the first and second columnar electrodes  11 ,  12 . 
     Subsequently, the coil substrate  5  (the main body part  10 ) is diced or scribed into pieces along cut surfaces C. In this case, the cut surfaces C constitute the first and second end surfaces  101 ,  102  of the main body part  10 . Therefore, the first columnar electrode  11 , the first via electrode  271 , the first connection wiring  25 , the second via electrode  272 , and the outer circumferential portion  21   b  of the first spiral wiring  21  are exposed from the first end surface  101  of the main body part  10 . The second columnar electrode  12 , the first via electrode  271 , the outer circumferential portion  22   b  of the second spiral wiring  22 , the second via electrode  272 , and the second connection wiring  26  are exposed from the second end surface  102  of the element body  10 . 
     Subsequently, the metal films  80  (see  FIG. 2 ) are disposed on the first and second side surfaces  101 ,  102  of the main body part  10 . The metal films  80  are formed by Cu plating treatment, for example. This plating treatment may be either electroless plating or electrolytic plating. As a result, on the first side surface  101 , the metal film  80  covers the first external electrode  61 , the first columnar electrode  11 , the first via electrode  271 , the first connection wiring  25 , the second via electrode  272 , and the outer circumferential portion  21   b  of the first spiral wiring  21 . On the second side surface  102 , the metal film  80  covers the second external electrode  62 , the second columnar electrode  12 , the first via electrode  271 , the outer circumferential portion  22   b  of the second spiral wiring  22 , the second via electrode  272 , and the second connection wiring  26 . In this way, the coil component  1  shown in  FIG. 2  is formed. 
     Although the coil substrate  5  is formed on one of both surfaces of the base  50  in the manufacturing method described above, the coil substrate  5  may be formed on each of both surfaces of the substrate  50 . Alternatively, pluralities of the first and second spiral wirings  21 ,  22  and the insulators  40  may be formed in parallel on one surface of the base  50  and may be divided into pieces so that a multiplicity of the coil substrates  5  can be formed at the same time. As a result, a plurality of the coil components  1  can be formed at the same time by using the one base  50 , and higher productivity can be achieved. 
     Second Embodiment 
       FIG. 4  is a view on X-direction arrow of a second embodiment of an electronic component of the present disclosure. The second embodiment is different from the first embodiment in the configuration of the via electrodes. This different configuration will hereinafter be described. In the second embodiment, the same constituent elements as the first embodiment are denoted by the same reference numerals as the first embodiment and therefore will not be described. 
     As shown in  FIG. 4 , in a coil component  1 A serving as the electronic component, a width of a first via electrode  271 A on one side in the lamination direction is smaller than a width of the first via electrode  271 A on the other side in the lamination direction. Specifically, a width of a lower end (the lower side in the Z direction) of the first via electrode  271 A is smaller than a width of an upper end (the upper side in the Z direction) of the first via electrode  271 A. Therefore, the shape of the first via electrode  271 A is a trapezoid when viewed in the X direction. In this case, due to a relationship of contact area, the interlayer peeling tends to occur on a connection surface with the first connection wiring  25  on the lower end side (one side) of the first via electrode  271 A. 
     Therefore, this configuration allows the metal film  80  to more effectively exert the interlayer peeling reduction effect. A second via electrode  272 A has the same configuration as the first via electrode  271 A. The second side surface  102  has the same configuration as the first side surface  101 . 
     The width of the upper end of the first via electrode may be smaller than the width of the lower end of the first via electrode. At least one of the first and second via electrodes may have the configuration described above. 
     Third Embodiment 
       FIG. 5  is a perspective view of a third embodiment of an electronic component of the present disclosure. The third embodiment is different from the first embodiment in the numbers of external electrodes and metal films. This different configuration will hereinafter be described. In the third embodiment, the same constituent elements as the first embodiment are denoted by the same reference numerals as the first embodiment and therefore will not be described. 
     As shown in  FIG. 5 , in a coil component  1 B serving as the electronic component, the multiple (in this embodiment, four) first external electrodes  61  are arranged in parallel along the Y direction on the one surface  103  of the main body part  10 . The multiple (in this embodiment, four) metal films  80  are arranged in parallel along the Y direction on the first side surface  101  of the main body part  10 . The first external electrodes  61  are respectively connected to the metal films  80 . 
     Similarly, the multiple (in this embodiment, four) second external electrodes  62  are arranged in parallel along the Y direction on the one surface  103  of the main body part  10 . The multiple (in this embodiment, four) metal films  80  are arranged in parallel along the Y direction on the second side surface  102  of the main body part  10 . The second external electrodes  62  are respectively connected to the metal films  80 . 
     Such an increase in the numbers of the first and second external electrodes  61 ,  62  and the metal films  80  makes the columnar electrodes  11 ,  12 , the spiral wirings  21 ,  22 , the via electrode  271 ,  272 , and the connection wirings  25 ,  26  smaller due to restriction on the size of the coil component  1 . 
     However, as described in the first embodiment, the metal films  80  cover the columnar electrodes  11 ,  12 , the spiral wirings  21 ,  22 , the via electrodes  271 ,  272 , and the connection wirings  25 ,  26  and therefore can effectively reduce the interlayer peeling thereof. 
     The present disclosure is not limited to the embodiments described above and may be changed in design without departing from the spirit of the present disclosure. For example, respective feature points of the first to third embodiments may variously be combined. 
     Although the metal film and the external electrode are separate members in the first embodiment, the metal film and the external electrode may be the same member (integrated). Although the columnar electrodes are disposed in the first embodiment, the columnar electrodes may not be included. 
     Although the columnar electrodes and the via electrodes are exposed on the side surfaces in the first embodiment, only the conductor layers may be exposed on the side surfaces without exposing the columnar electrodes and the via electrodes on the side surfaces. In this case, the metal film is formed by plating from the conductor layers on both sides of the insulating layer, extending over the insulating layer. Consequently, the metal film covers the insulating layer between the conductor layers. Therefore, the via electrode may be covered with the insulating layer without being exposed on the side surface of the main body part. In this case, the multiple conductor layers are exposed on the side surface in the lamination direction, and the main body part is configured to have the via electrode connecting the conductor layers adjacent to each other in the lamination direction while the metal film connects the conductor layers adjacent to each other. If the metal film is not included, since the via electrode is usually smaller than the conductor layer and makes an area of a connection surface smaller between the conductor layer and the via electrode, the interlayer peeling tends to occur on the connection surface due to thermal expansion of the insulating layer. On the other hand, in the configuration described above, the metal film connects the conductor layers adjacent to each other in the lamination direction and therefore restrains the expansion and contraction of the insulating layer due to heat between the conductor layers. Therefore, even in the configuration without exposing the via electrode on the side surface of the main body part, i.e., the configuration without contact between the metal film and the via electrode, the interlayer peeling can be reduced between the conductor layer and the via electrode. 
     Although the configuration including the metal film, the columnar electrode, and the trapezoidal via electrode is described in the second embodiment, the configuration may include only the metal film and the trapezoidal via electrode. 
     Although the configuration including the multiple metal films, the multiple external electrodes, the columnar electrode, and the via electrode is described in the third embodiment, the configuration may include only the multiple metal films and the multiple external electrodes. 
     Although two layers of the spiral wirings are included in the first embodiment, three or more layers of the spiral wirings may be included. In other words, although two conductor layers are included, three or more conductor layers may be included, and when three or more conductor layers are included, the increased number of laminated insulation layers makes the expansion and contraction due to heat larger so that the interlayer peeling is more likely to occur, and therefore, the effect of the metal layer reducing the interlayer peeling becomes more effective. Although three insulating layers are included, four or more insulating layers may be included. 
     Although the electronic component is a coil component in the first embodiment, the electronic component may be a capacitor etc. In the case of a coil component, since the conductor layer constitutes a helical wiring, i.e., a wiring with a narrow width, the connection surface of the conductor layer with the other member tends to be small so that the interlayer peeling is more likely to occur, and therefore, the effect of the metal layer reducing the interlayer peeling becomes more effective. 
     EXAMPLE 
     An example of the first embodiment will be described. 
       FIG. 6A  shows a relationship between the number of times of reflow and DC electric resistance Rdc of a coil component that is an example of the first embodiment at the time of mounting on a mounting substrate via solder. The DC electric resistance Rdc was measured as a DC electric resistance value (in Ω) between external electrodes (between the external electrodes  61 ,  62  in the coil component  1 ). As shown in  FIG. 6A , in the example, the DC electric resistance Rdc was almost unchanged before and after the reflow. 
       FIG. 6B  shows a relationship between the number of times of reflow and the DC electric resistance Rdc of a coil component without the metal film that is a comparative example of the first embodiment. The measurement method of the DC electric resistance Rdc was the same as  FIG. 6A . As shown in  FIG. 6B , in the comparative example, the DC electric resistance Rdc increased before and after the reflow. This means the occurrence of the interlayer peeling between the conductor layers due to heat during the reflow. 
     As described above, in the example in which the metal film is disposed, the interlayer peeling between the conductor layers can be reduced. In the example, additionally, the DC electric resistance Rdc before the reflow was low as compared to the comparative example. It is considered that the DC electric resistance Rdc becomes smaller since a path going through the metal film is formed between the external electrode and the conductor layer in the example and this path does not pass through the interface, in which the DC electric resistance Rdc tends to be high, between the conductor layer and the via electrode. Therefore, the configuration of the example also has an effect of reducing the DC electric resistance between the external electrode and the conductor layer.