Patent Publication Number: US-2020304025-A1

Title: Inductor component, package component, and switching regulator

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 15/278,198 filed Sep. 28, 2016, which claims benefit of priority to Japanese Patent Application 2015-197028 filed Oct. 2, 2015, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an inductor component, a package component, and a switching regulator. 
     BACKGROUND 
     An inductor component described in Japanese Patent Publication No. 2013-225718 has traditionally been present. This inductor component includes a glass epoxy substrate, spiral wires disposed on both sides of the glass epoxy substrate, insulating resins that each cover the spiral wire, and cores that cover the insulating resin thereon and therebeneath. The core is a metal magnetic powder-including resin and the core includes metal magnetic powder whose average particle diameter is 20 to 50 μm. 
     SUMMARY 
     Problems to be Solved by the Disclosure 
     Electric-power saving techniques are increasingly demanded with the improvement of the performance of PCs and servers, and the prevalence of mobile devices. In this situation, an IVR (Integrated Voltage Regulator) technique attracts attention as a technique of reducing the power consumption of a CPU (Central Processing Unit). 
     In a traditional system, as depicted in  FIG. 12 , a voltage is supplied from a power source  105  to N CPUs  101  in an IC (Integrated Circuit) chip  100  through one VR (Voltage Regulator)  103 . 
     On the other hand, in a system employing the IVR technique, as depicted in  FIG. 13 , an individual VR  113  regulating the voltage from the power source  105  is disposed for each of the CPUs  101 , and the voltage supplied to the CPU  101  is individually controlled corresponding to the clock operation frequency of the CPU  101 . 
     The supplied voltage needs to be varied at a high speed to control the supplied voltage to correspond to the variation of the operation frequency of the CPU  101 , and the VR  113  needs a chopper circuit that executes a high speed switching operation at a frequency such as 10 to 100 MHz. 
     Associated with this, a high frequency power inductor is also needed that can cope with the high speed switching operation at the frequency such as 10 to 100 MHz and that can energize at a level of several A as a sufficient current to the core during the operation of the CPU  101 , as the inductor used in a ripple filter on the output side of the chopper circuit. 
     Additionally, the IVR also aims at facilitating downsizing simultaneously with the electric-power saving by integrating the above system with the IC chip  110 , and a small-size high frequency power inductor capable of being incorporated in the IC package is demanded. Especially, downsizing of the system is advanced by using three-dimensional mounting such as SiP (System in Package) or PoP (Package on Package) and, in this situation, a thin-type high frequency power inductor having a thickness, for example, equal to or smaller than 0.33 mm is needed that can be incorporated in an IC package substrate or that can be mounted on a BGA (Ball Grid Array) side of the substrate. 
     Because the traditional inductor component has the spiral wires disposed on both of the sides of the glass epoxy substrate, the thickness of the glass epoxy substrate however acts as an obstructive factor and the reduction of the thickness thereof is difficult. The glass epoxy substrate has the thickness of at least about 80 μm due to the limit of the thickness of the glass cloth and the interlayer pitch of the spiral wires in the two layers cannot therefore be reduced any more. When the thickness of this substrate is forcibly reduced, the strength of the substrate cannot be maintained, and wire processing and the like become difficult. 
     Because the core includes the metal magnetic powder whose average particle diameter is 20 to 50 μm, the size of the metal magnetic powder is large. The thickness of each of the cores on and beneath the insulating resin is thereby increased and reduction of the thickness is difficult. For example, to include the metal magnetic powder in the insulating resin that covers each of the spiral wires to improve the L-value, the wire pitch needs to be secured to be sufficiently larger than the average particle diameter of the metal magnetic powder and downsizing is also difficult. 
     Because the size of the metal magnetic powder is large, the eddy current loss is large in the metal magnetic powder and, in the high speed switching operation at a frequency such as 50 MHz to 100 MHz, the loss is large and the high frequency is difficult to be supported. 
     An object of the present disclosure is to provide an inductor component that can support any high frequency and maintains the strength thereof and that can facilitate reduction of the height and downsizing. 
     Solutions to the Problems 
     To achieve the object, the inductor component of the present disclosure includes: 
     a composite body that includes a plurality of composite layers each including a composite material of an inorganic filler and a resin; and 
     a plurality of spiral wires that each are stacked on the composite layer, the spiral wires each being covered with the other composite layer, wherein 
     the average particle diameter of the inorganic filler is equal to or smaller than 5 μm, 
     the wire pitch of the spiral wires is equal to or smaller than 10 μm, and 
     the interlayer pitch between adjacent spiral wires is equal to or smaller than 10 μm. 
     According to the inductor component of the present disclosure, the spiral wires are each stacked on the composite layer that includes the composite material of the inorganic filler and the resin. As to the composite layer, any physical defect such as a crack is not generated therein even when the composite layer is formed to be a thin film, a sufficient strength thereof can be maintained even when the composite layer is not disposed on a glass epoxy substrate or the like, and reduction of the height can be facilitated by excluding the thickness of the glass epoxy substrate. 
     Because the average particle diameter of the inorganic filler is equal to or smaller than 5 μm, the wire pitch and the interlayer pitch of the spiral wires can be reduced and, because the wire pitch and the interlayer pitch of the spiral wires are each equal to or smaller than 10 μm, reduction of the height and downsizing can be facilitated. 
     Because the average particle diameter of the inorganic filler is equal to or smaller than 5 μm, when the inorganic filler is a magnetic substance, the eddy current loss in the magnetic substance is small and, even for a high speed switching operation at a frequency such as 50 MHz to 100 MHz, the loss is small and the high frequency can be supported. 
     The high frequency can be supported and reduction of the height and downsizing can be facilitated, maintaining the strength. 
     In one embodiment of the inductor component, the composite body includes a magnetic composite body whose inorganic filler includes a metal magnetic material. 
     According to the embodiment, because the composite body includes the magnetic composite body, even when the inorganic filler is formed to be fine particles having the average particle size equal to or smaller than 5 μm, high magnetic permeability can be secured and the Q-value of the inductor at a high frequency can be increased. 
     In one embodiment of the inductor component, the composite body includes 
     an insulating composite body that covers the spiral wire, the inorganic filler being an insulating substance; and 
     the magnetic composite body covers the insulating composite body. 
     According to the embodiment, because the composite body includes the insulating composite body and the magnetic composite body, the insulating composite body improves the insulation between the wires and between the layers of the spiral wires and enables further downsizing and reduction of the height or reduction of the resistance of the spiral wires, and the Q-value at the high frequency can be maintained. With the magnetic composite body, a high inductance value can be acquired. 
     In one embodiment of the inductor component, the inorganic filler of the insulating composite body is SiO 2  whose average particle diameter is equal to or smaller than 0.5 μm. 
     According to the embodiment, because the inorganic filler of the insulating composite body is SiO 2  whose average particle diameter is equal to or smaller than 0.5 μm, the insulation between the wires and between the layers of the spiral wires can be enhanced, and downsizing and reduction of the height can further be facilitated. 
     In one embodiment of the inductor component, the content rate of the inorganic filler in the insulating composite body is equal to or higher than 20 Vol % and equal to or lower than 70 Vol % relative to the insulating composite body. 
     According to the embodiment, because the content rate of the inorganic filler is equal to or higher than 20 Vol % and equal to or lower than 70 Vol %, the fluidity and the linear expansion coefficient of the composite body can be set to be adequate, and downsizing and reduction of the height, and improvement of the reliability and the insulation can concurrently be established. 
     In one embodiment of the inductor component, the inorganic filler of the magnetic composite body is an FeSi-based alloy, an FeCo-based alloy, an FeNi-based alloy, or an amorphous alloy of these alloys, having the average particle diameter that is equal to or smaller than 5 μm. 
     According to the embodiment, because the inorganic filler of the magnetic composite body is an FeSi-based alloy, an FeCo-based alloy, an FeNi-based alloy, or an amorphous alloy of these alloys, having the average particle diameter that is equal to or smaller than 5 μm, the Q-value of the inductor at a high frequency can be increased. 
     In one embodiment of the inductor component, the content rate of the inorganic filler in the magnetic composite body is equal to or higher than 20 Vol % and equal to or lower than 70 Vol % relative to the magnetic composite body. 
     According to the embodiment, because the content rate of the inorganic filler is equal to or higher than 20 Vol % and equal to or lower than 70 Vol %, the fluidity and the linear expansion coefficient are set to be adequate, and downsizing and reduction of the height and high reliability, and a high Q-value at a high frequency can concurrently be established. 
     In one embodiment of the inductor component, the number of turns of the inductor including the spiral wires is equal to or smaller than 10. 
     According to the embodiment, because the number of turns of the inductor including the spiral wires is equal to or smaller than 10, downsizing can be facilitated securing an L-value necessary during a high speed switching operation. 
     In one embodiment of the inductor component, the thickness of a composite body positioned in an upper portion of the spiral wires in a stacking direction and the thickness of a composite body positioned in a lower portion of the spiral wires in the stacking direction are equal to each other and are each equal to or larger than 10 μm and equal to or smaller than 50 μm. 
     According to the embodiment, because the thickness of the composite body in the upper portion and the thickness of the composite body in the lower portion are equal to each other and are each equal to or larger than 10 μm and equal to or smaller than 50 μm, the L-value necessary in a high speed switching operation can be acquired with a small thickness and reduction of the thickness can be facilitated. 
     In one embodiment of the inductor component, the inductor component further includes a pair of external terminals that are disposed at least one of over or under the spiral wires in the stacking direction, the pair of external terminals being electrically connected to the spiral wires, and wherein 
     end faces of the pair of external terminals in the stacking direction are positioned in the same plane as that of an end face of the composite body in the stacking direction. 
     The external terminals in this case refer to wires such as Cu wires and do not include any plating that covers the wires. 
     According to the embodiment, because the end faces of the pair of external terminals are positioned in the same plane as that of the end face of the composite body, the external terminals do not protrude from the end face of the composite body and reduction of the height can be facilitated. 
     In one embodiment of the inductor component, the pair of external terminals is buried in the composite body. 
     According to the embodiment, because the external terminals are buried in the composite body, downsizing can be facilitated. The external terminals can be disposed at arbitrary positions on the end face of the composite body in the stacking direction and the degree of freedom is increased for the designing of the layout of the wires and terminals to be connected. 
     In one embodiment of the inductor component, one of the pair of external terminals is disposed both over and under the spiral wires in the stacking direction, and the upper and the lower external terminals are electrically connected to each other, and the other of the pair of external terminals is disposed at least over the spiral wires in the stacking direction. 
     According to the embodiment, because the one of the pair of external terminals is disposed both over and under the spiral wires in the stacking direction, wires conductive for the upper and the lower external terminals can therefore be disposed on the upper and the lower faces of the substrate when the inductor component is buried in the substrate. The output side of a chopper circuit can be connected in the shortest course by the upper and the lower external terminals that are electrically connected to each other, without running any more wire around. The ESR and the ESL of a smoothing capacitor on the output side can therefore be reduced and the ripple voltage of the output can be reduced. 
     In one embodiment of the package component, the package component includes: 
     a substrate; and 
     the inductor component that is buried in the substrate, wherein 
     the external terminals on an upper side of the inductor component is disposed at a side of an upper face of the substrate, and the external terminal on a lower side of the inductor component is disposed at a side of a lower face of the substrate, and wherein 
     wires each electrically connected to the external terminal on the upper side are disposed on the upper face of the substrate and a wire electrically connected to the external terminal on the lower side is disposed on the lower face of the substrate. 
     According to the embodiment, the inductor component is buried in the substrate, a wire electrically connected to the external terminal on the upper side is disposed on the upper face of the substrate, and a wire electrically connected to the external terminal on the lower side is disposed on the lower face of the substrate. The output side of the chopper circuit can be connected in the shortest course by the upper and the lower external terminals electrically connected to each other, without running any more wire around. The ESR and the ESL of the smoothing capacitor on the output side can therefore be reduced and the ripple voltage of the output can be reduced. 
     In one embodiment of a switching regulator, the switching regulator includes: 
     the package component; 
     a switching element that opens or closes electric connection between an external power source and the inductor component; and 
     a smoothing capacitor that smoothes an output voltage from the inductor component, wherein 
     the switching element is disposed on a side of the upper face of the substrate of the package component, and is electrically connected to the wire connected to the other of the pair of external terminals, 
     the smoothing capacitor is disposed on a side of the lower face of the substrate in the package component and is electrically connected to the wire on the lower side of the wires connected to the one of the pair of external terminals, and 
     the wire on the upper side of the wires connected to the one of the pair of external terminals is an output terminal. 
     According to the embodiment, the smoothing capacitor is connected to the wire on the lower face of the substrate of the package component, and the side of the output terminal connected to a load such as a central processing unit is connected to the wire on the upper face of the substrate of the package component similarly to the switching element. The inductor component of the package component, and the load and the smoothing capacitor can thereby be connected in the shortest course using the upper and the lower external terminals, without running any more wire around. The ESR and the ESL of the smoothing capacitor can therefore be reduced and the ripple voltage of the output can be reduced. 
     Effect of the Disclosure 
     According to the inductor component of the present disclosure, a high frequency can be supported and reduction of the height and downsizing can be facilitated, maintaining the strength. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an exploded perspective diagram of a first embodiment of an inductor component of the present disclosure. 
         FIG. 1B  is a cross-sectional diagram of the inductor component. 
         FIG. 2A  is a diagram for explaining a manufacture method of the inductor component. 
         FIG. 2B  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2C  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2D  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2E  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2F  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2G  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2H  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2I  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 2J  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 3  is a graph of a frequency property of a composite body to a filling amount of an inorganic filler. 
         FIG. 4  is a graph of a relation between an inductance value and thicknesses of an upper and a lower magnetic composite bodies. 
         FIG. 5  is a cross-sectional diagram of a second embodiment of the inductor component of the present disclosure. 
         FIG. 6A  is a diagram for explaining a manufacture method of the inductor component. 
         FIG. 6B  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6C  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6D  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6E  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6F  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6G  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6H  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6I  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6J  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 6K  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 7  is a cross-sectional diagram of a third embodiment of the inductor component of the present disclosure. 
         FIG. 8A  is a diagram for explaining a manufacture method of the inductor component. 
         FIG. 8B  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 8C  is a diagram for explaining the manufacture method of the inductor component. 
         FIG. 9  is a cross-sectional diagram of a first embodiment of a package component of the present disclosure. 
         FIG. 10A  is a diagram for explaining a manufacture method of the package component. 
         FIG. 10B  is a diagram for explaining the manufacture method of the package component. 
         FIG. 10C  is a diagram for explaining the manufacture method of the package component. 
         FIG. 10D  is a diagram for explaining the manufacture method of the package component. 
         FIG. 10E  is a diagram for explaining the manufacture method of the package component. 
         FIG. 10F  is a diagram for explaining the manufacture method of the package component. 
         FIG. 11A  is a cross-sectional diagram of a first embodiment of a switching regulator of the present disclosure. 
         FIG. 11B  is an equivalent circuit diagram of the switching regulator. 
         FIG. 12  is a simplified configuration diagram of a traditional system. 
         FIG. 13  is a simplified configuration diagram of an IVR system. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be described in detail with reference to depicted embodiments. 
     First Embodiment 
       FIG. 1A  is an exploded perspective diagram of the first embodiment of an inductor component of the present disclosure. 
       FIG. 1B  is a cross-sectional diagram of the inductor component. The drawings are schematic, and the relationship among the scales and dimensions of members may be different from the actual relationship thereamong. As depicted in  FIG. 1A  and  FIG. 1B , the inductor component  1  is mounted on an electronic apparatus such as, for example, a personal computer, a DVD player, a digital camera, a television, a mobile phone, or automotive electronics. 
     The inductor component  1  includes two layers of spiral wires  21  and  22 , a magnetic composite body  30  (to be an example of a composite body) that covers the two layers of spiral wires  21  and  22 . “Covering an object” used herein refers to covering at least a portion of the object. In  FIG. 1A , in the magnetic composite body  30 , portions  32  and  33  to have the spiral wires  21  and  22  buried therein are depicted integral with each other. 
     The first and the second spiral wires  21  and  22  are sequentially disposed from a lower layer to an upper layer. The description will be made herein assuming that the up-and-down direction of the inductor component  1  matches with the up-and-down direction of the page carrying  FIG. 1B  thereon. The first and the second spiral wires  21  and  22  are electrically connected in the stacking direction. The “stacking direction” refers to a direction for the layers to be stacked and means, for example, a direction along the up-and-down direction of the page carrying  FIG. 1B  thereon. The first and the second spiral wires  21  and  22  are each formed in a spiral shape in a plane. The first and the second spiral wires  21  and  22  each include a low resistance metal such as, for example, Cu, Ag, or Au. Preferably, a low-resistance and narrow-pitch spiral wire can be formed by using Cu plating formed using a semi-additive process. 
     External terminals  11  and  12  are disposed above the first and the second spiral wires  21  and  22  in the stacking direction. The first external terminal  11  is electrically connected to the first spiral wire  21  and the second external terminal  12  is electrically connected to the second spiral wire  22 . The external terminals  11  and  12  each include, for example, the same material as that of the spiral wires  21  and  22 . The external terminals  11  and  12  refer to wires such as Cu wires and do not include any plating that covers the wires. 
     The magnetic composite body  30  includes first to fourth composite layers  31  to  34 . The first to the fourth composite layers  31  to  34  are sequentially disposed from a lower layer to an upper layer. The magnetic composite body  30  includes a composite material of an inorganic filler and a resin. The resin is an organic insulating material including, for example, an epoxy-based resin, bismaleimide, a liquid crystal polymer, polyimide, or the like. The average particle diameter of the inorganic filler is equal to or smaller than 5 μm. The “average particle diameter” used herein refers to the particle diameter that corresponds to 50% of the integrated value in the grain size distribution acquired using a laser diffraction and scattering method. The inorganic filler is a magnetic substance. The inorganic filler is, for example, an FeSi-based alloy such as FeSiCr, an FeCo-based alloy, an Fe-based alloy such as NiFe, or an amorphous alloy of these alloys, having an average particle diameter that is equal to or smaller than 5 μm. Preferably, the content rate of the inorganic filler is equal to or higher than 20 Vol % and equal to or lower than 70 Vol % relative to the magnetic composite body  30 . 
     The first spiral wire  21  is stacked on the first composite layer  31 . The second composite layer  32  is stacked on the first spiral wire  21  and covers the first spiral wire  21 . The second spiral wire  22  is stacked on the second composite layer  32 . The third composite layer  33  is stacked on the second spiral wire  22  and covers the second spiral wire  22 . The fourth composite layer  34  is stacked on the third composite layer  33 . In this manner, each of the first and the second spiral wires  21  and  22  is stacked on the composite layer and is covered by the other composite layer that is an upper layer. The magnetic composite body  30  is also disposed in an inner diameter portion of each of the first and the second spiral wires  21  and  22  that correspond to inner magnetic paths. 
     The first and the second spiral wires  21  and  22  are disposed centering the same one axis. The first spiral wire  21  and the second spiral wire  22  are wound in the same one direction, seen from the axis direction (the stacking direction). 
     The second spiral wire  22  is electrically connected to the first spiral wire  21  through a via wire  27  that extends in the stacking direction. Another via wire  27  is also disposed in the second composite layer  32 . An inner circumference part  21   a  of the first spiral wire  21  and an inner circumference part  22   a  of the second spiral wire  22  are electrically connected to each other through the via wires  27 . The first spiral wire  21  and the second spiral wire  22  thereby constitute one inductor. 
     An outer circumference part  21   b  of the first spiral wire  21  and an outer circumference part  22   b  of the second spiral wire  22  are positioned on the sides of both ends of the magnetic composite body  30 , seen from the stacking direction. The first external terminal  11  is positioned on the side of the outer circumference part  21   b  of the first spiral wire  21  and the second external terminal  12  is positioned on the side of the outer circumference part  22   b  of the second spiral wire  22 . 
     The outer circumference part  21   b  of the first spiral wire  21  is electrically connected to the first external terminal  11  through the via wire  27  that is disposed in the second composite layer  32 , a first connection wire  25  that is disposed on the second composite layer  32 , and the via wire  27  that is disposed in the third composite layer  33 . The outer circumference part  22   b  of the second spiral wire  22  is electrically connected to the second external terminal  12  through the via wire  27  that is disposed in the third composite layer  33 . The outer circumference part  22   b  of the second spiral wire  22  is electrically connected to a second connection wire  26  that is disposed on the first composite layer  31  through the via wire  27  that is disposed in the second composite layer  32 . 
     The thickness in the height direction of each of the first and the second spiral wires  21  and  22  is equal to or larger than 40 μm and, preferably, is equal to or smaller than 120 μm. The “height direction” is the direction along the up-and-down direction of the inductor component  1 . The wire pitch of each of the first and the second spiral wires  21  and  22  is equal to or smaller than 10 μm and, preferably, is equal to or larger than 3 μm. The interlayer pitch between adjacent the spiral wires  21  and  22  is equal to or smaller than 10 μm and, preferably, is equal to or larger than 3 μm. The wire pitch and the interlayer pitch are designed values and the manufacture dispersion thereof is about ±20%. 
     The DC resistance can sufficiently be reduced by setting the wire thickness to be equal to or larger than 40 μm. The wire aspect to be the ratio of the thickness in the height direction to that in the width direction of the wire is prevented from becoming extremely high by setting the wire thickness to be equal to or smaller than 120 μm, and any process dispersion can thereby be suppressed. The wire width can be taken to be large by setting the wire pitch to be equal to or smaller than 10 μm, and the DC resistance can thereby be reliably reduced. The insulation between the wires can sufficiently be secured by setting the wire pitch to be equal to or larger than 3 μm. The height can be reduced by setting the interlayer pitch to be equal to or smaller than 10 μm. Any interlayer short-circuiting can be suppressed by setting the interlayer pitch to be equal to or larger than 3 μm. 
     The number of turns of the inductor including the first and the second spiral wires  21  and  22  is equal to or greater than one and equal to or smaller than 10 and is, preferably, equal to or smaller than 1.5 to 5. In this embodiment, the number of turns is 2.5. 
     The thickness H 1  of the magnetic composite body  30  positioned in the upper portion of the second spiral wire  22  in the stacking direction and the thickness H 2  of the magnetic composite body  30  positioned in the lower portion of the first spiral wire  21  in the stacking direction are equal to each other and are each equal to or larger than 10 μm and equal to or smaller than 50 μm. “Being equal” herein includes being substantially equal in addition to being completely equal. 
     Upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  in the stacking direction are positioned in the same plane as that of an upper end face  30   a  of the magnetic composite body  30  in the stacking direction. The first and the second external terminals  11  and  12  are buried in the magnetic composite body  30 . The upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  in the stacking direction may be covered with SnNi plating to improve the solder wettability thereof for the solder mounting. 
     A manufacture method of the inductor component  1  will be described. 
     As depicted in  FIG. 2A , a base platform  50  is prepared. The base platform  50  includes an insulating substrate  51  and base metal layers  52  disposed on both faces of the insulating substrate  51 . In this embodiment, the insulating substrate  51  is a glass epoxy substrate and the base metal layer  52  is a Cu foil sheet. The thickness of the base platform  50  does not influence the thickness of the inductor component  1  and any base platform  50  having a thickness suitable for easy handling may properly be used because of the reasons such as warpage generated in the processing. 
     As depicted in  FIG. 2B , a dummy metal layer  60  is bonded to one face of the base platform  50 . In this embodiment, the dummy metal layer  60  is a Cu foil sheet. Because the dummy metal layer  60  is bonded to the base metal layer  52  of the base platform  50 , the dummy metal layer  60  is bonded to a smooth face of the base metal layer  52 . The adhesive force between the dummy metal layer  60  and the base metal layer  52  can therefore be weakened and, in the post-process, the base platform  50  can therefore be easily peeled off from the dummy metal layer  60 . Preferably, the adhesive bonding the base platform  50  and the dummy metal layer  60  to each other is a low adhesion adhesive. To weaken the adhesive force between the base platform  50  and the dummy metal layer  60 , the bonding surface of each of the base platform  50  and the dummy metal layer  60  is advantageously set to be a glossy surface. 
     The first composite layer  31  is thereafter stacked on the dummy metal layer  60  that is temporarily bonded to the base platform  50 . In this case, the first composite layer  31  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. 
     As depicted in  FIG. 2C , the first spiral wire  21  and the second connection wire  26  are stacked on the first composite layer  31 . The first spiral wire  21  and the second connection wire  26  are not in contact with each other. The second connection wire  26  is disposed on a side opposite to that of the outer circumference part  21   b . For example, a power supply film for the SAP (Semi Additive Process) is disposed on the first composite layer  31  using electroless plating, sputtering, vapor deposition, or the like. After disposing the power supply film, a photosensitive resist is applied or attached to the power supply film and a wire pattern is formed using photolithography. Metal wires corresponding to the wires  21  and  22  are thereafter disposed using the SAP. After disposing the metal wires, the photosensitive resist is peeled and removed using a chemical solution and the power supply film is removed by etching. Additional Cu electrolytic plating is thereafter applied using the metal wires as a power supply part, and the wires  21  and  22  each having a narrower space can thereby be acquired. In this embodiment, a Cu wire having L (the wire width)/S (the wire space (the wire pitch))/t (the wire thickness) to be 50/30/60 μm is disposed using the SAP and a wire having L/S/t=70/10/70 μm can thereafter be acquired by executing additional Cu electrolytic plating therefor that corresponds to the thickness of 10 μm. 
     As depicted in  FIG. 2D , the second composite layer  32  is stacked on the first spiral wire  21  to cover the first spiral wire  21  with the second composite layer  32 . The second composite layer  32  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. In this case, the thickness of the second composite layer  32  above the first spiral wire  21  is set to be equal to or smaller than 10 μm. The interlayer pitch of the first and the second spiral wires  21  and  22  can thereby be set to be equal to or smaller than 10 μm. 
     To secure the filling into the wire pitch (for example, 10 μm) of the first spiral wire  21 , the inorganic filler (magnetic substance powder) included in the second composite layer  32  needs to have the particle diameter that is sufficiently smaller than the wire space of the first spiral wire  21 . To realize the reduction of the thickness of the component, the interlayer pitch for the continued wire in the upper portion needs to be reduced to be equal to or smaller than, for example, 10 μm and the magnetic substance powder therefore also needs to have a particle diameter that is sufficiently small. 
     As depicted in  FIG. 2E , via holes to be filled with the via wires  27  are disposed in the second composite layer  32  using laser processing or the like. The via holes are thereafter filled with the via wires  27 , and the second spiral wire  22  and the first connection wire  25  are stacked on the second composite layer  32 . The second spiral wire  22  and the first connection wire  25  are not in contact with each other. The first connection wire  25  is disposed on a side opposite to that of the outer circumference part  22   b . In this case, the via wires  27 , the second spiral wire  22 , and the first connection wire  25  can be disposed using the same process as that used for the first spiral wire  21 . 
     As depicted in  FIG. 2F , the third composite layer  33  is stacked on the second spiral wire  22  to cover the second spiral wire  22  with the third composite layer  33 . The third composite layer  33  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. 
     As depicted in  FIG. 2G , the via holes to be filled with the via wires  27  are disposed in the third composite layer  33  using laser processing or the like. The via holes are thereafter filled with the via wires  27 , and the first and the second external terminals  11  and  12  each having a columnar shape are stacked on the third composite layer  33 . In this case, the via wires  27 , and the first and the second external terminals  11  and  12  can be disposed using the same process as that used for the first spiral wire  21 . 
     As depicted in  FIG. 2H , the fourth composite layer  34  is stacked on the first and the second external terminals  11  and  12  to cover the first and the second external terminals  11  and  12  with the fourth composite layer  34 . The fourth composite layer  34  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. 
     The base platform  50  is peeled off from the dummy metal layer  60  in the adhesion surface between the one face of the base platform  50  (the base metal layer  52 ) and the dummy metal layer  60 . The dummy metal layer  60  is removed by etching or the like and, as depicted in  FIG. 2I , an inductor substrate  5  is formed. 
     As depicted in  FIG. 2J , the fourth composite layer  34  to be the uppermost layer of the inductor substrate  5  is processed to be a thin film using a grinding process. At this time, a portion of each of the first and the second external terminals  11  and  12  is exposed and upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  are thereby positioned in the same plane as that of the upper end face  30   a  of the magnetic composite body  30 . In this case, reduction of the thickness of the component can be facilitated by grinding the fourth composite layer  34  to have a thickness that is sufficient to be able to acquire an inductance value. In this embodiment, the thickness of the magnetic composite body  30  positioned in the upper portion of the second spiral wire  22  in the stacking direction (corresponding to the thickness H 1  of  FIG. 1B ) can be set to be 40 μm. 
     The inductor substrate  5  is thereafter divided into individual chips by dicing and scribing to form the inductor components  1  each depicted in  FIG. 1B . After the division into individual chips, a plating film of NiSn or the like may be disposed on the first and the second external terminals  11  and  12  using a method such as barrel plating to enhance the mounting property. 
     Though the inductor substrate  5  is formed on one face of both faces of the base platform  50 , the inductor substrate  5  may be formed on each of both faces of the base platform  50 . High productivity can thereby be achieved. 
     According to the inductor component  1 , because the first and the second spiral wires  21  and  22  are stacked on the composite layer of the magnetic composite body  30 , any physical defect such as a crack is not generated in the composite layer even when the composite layer is formed to be a thin film, a sufficient strength thereof can be maintained even when the composite layer is not disposed on the glass epoxy substrate or the like, and reduction of the height can be facilitated by excluding the thickness of the glass epoxy substrate. 
     Because the average particle diameter of the inorganic filler of the magnetic composite body  30  is equal to or smaller than 5 μm, the wire pitch and the interlayer pitch of the first and the second spiral wires  21  and  22  can be reduced and, because the wire pitch and the interlayer pitch of the first and the second spiral wires  21  and  22  are each equal to or smaller than 10 μm, reduction of the height and downsizing can be facilitated. 
     Because the average particle diameter of the inorganic filler to be a magnetic substance is equal to or smaller than 5 μm, the eddy current loss in the magnetic substance is small, the loss is small for a high speed switching operation at a frequency such as 50 MHz to 100 MHz, and the support for the high frequency is enabled. 
     Because the magnetic composite body  30  includes the composite material of the inorganic filler and the resin, any physical defect such as a crack is not generated therein even when the height thereof is reduced. 
     The high frequency can be supported, and reduction of the height and downsizing can be facilitated maintaining the strength. 
     According to the inductor component  1 , because the composite body includes the magnetic composite body  30 , high magnetic permeability can be secured and the Q-value of the inductor at a high frequency can be increased even when the average particle diameter of the inorganic filler of the magnetic substance is set to be equal to or smaller than 5 μm to be fine particles. 
     According to the inductor component  1 , because the inorganic filler of the magnetic composite body  30  is an FeSi-based alloy, an FeCo-based alloy, or an amorphous alloy of these alloys, having the average particle diameter equal to or smaller than 5 μm, the Q-value of the inductor at a high frequency can be increased. 
     Using an Fe-based material as the inorganic filler provides a higher magnetic moment compared to that of any other soft magnetic material and, even when the particle diameter is reduced, a relatively high magnetic permeability can be acquired. The surface of the inorganic filler may be treated to be insulative using phosphate treatment, silica coating, or the like to enhance the insulation of the magnetic composite body  30 . The high frequency performance is degraded due to the eddy current loss when the insulation of the surface is low. 
     According to the inductor component  1 , because the content rate of the inorganic filler is equal to or higher than 20 Vol % and equal to or lower than 70 Vol %, the fluidity and a high Q-value can concurrently be established.  FIG. 3  is a graph of a frequency property to a filling amount (the content rate) of the inorganic filler.  FIG. 3  depicts an approximate straight line acquired when frequencies (MHz) are plotted that are each acquired when the dielectric tangent (tan δ) is 0.01 with a filling amount (Vol %) of the inorganic filler. 
     The filling amount (the content rate) is represented by {the volume of the inorganic filler/(the volume of the inorganic filler+the volume of the resin)}×100. For example, this complies with JIS K 7250 (2006) “Plastic-How to Determine Ash Percentage”. Otherwise, simply, the three-dimensional dispersion state of the filler is acquired by executing SEM observation in the depth direction using an FIB-SEM. This data is the data acquired using an FIB-SEM. 
     As depicted in  FIG. 3 , any loss can be suppressed even for a high speed switching operation at an operation frequency of 10 MHz and the property can be maintained even at a high frequency by setting the content rate of the inorganic filler to be equal to or lower than 70 Vol %. The content rate of the inorganic filler is, preferably, equal to or lower than 65 Vol % and, especially, is, more preferably, equal to lower than 60 Vol %. From  FIG. 3 , any loss can be suppressed for a high speed switching operation at a frequency up to 50 MHz when the content rate is equal to or lower than 65 Vol % and up to 100 MHz when the content rate is equal to or lower than 60 Vol %, and the property can be maintained at a high frequency. 
     Preferably, the content rate of the inorganic filler is equal to higher than 20 Vol % and, in this case, the fluidity and the linear expansion coefficient of the composite body can adequately be secured and a composite body can be acquired whose downsizing, height reduction, and reliability improvement can be facilitated. 
     According to the inductor component  1 , because the number of turns of the inductor including the first and the second spiral wires  21  and  22  is equal to or smaller than 10, downsizing can be facilitated securing the L-value necessary for a high speed switching operation. 
     According to the inductor component  1 , because the thickness H 1  of the magnetic composite body  30  in the upper portion and the thickness H 2  of the magnetic composite body  30  in the lower portion are equal to each other and are each equal to or larger than 10 μm and equal to or smaller than 50 μm, the L-value necessary for a high speed switching operation can be acquired with a small thickness and reduction of the thickness can be facilitated. 
       FIG. 4  depicts the relation between the inductance value (the L-value) and the thicknesses of the magnetic composite bodies on and beneath the spiral wires, for each number of the turns of the spiral wires.  FIG. 4  depicts the values measured using an electromagnetic field simulation concerning the magnetic composite body that satisfies the conditions of this application. A solid line therein represents the case of 2.5 turns and a dotted line therein represents the case of 4.5 turns. As depicted in  FIG. 4 , because the L-value saturates against the thickness, reduction of the height of the component can be facilitated securing the L-value necessary for a high speed switching operation by setting the thicknesses of the magnetic composite bodies thereon and therebeneath to each be equal to or smaller than 50 μm. 
     According to the inductor component  1 , because the upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  are positioned in the same plane as that of the upper end face  30   a  of the magnetic composite body  30 , the first and the second external terminals  11  and  12  do not protrude from the upper end face  30   a  of the magnetic composite body  30  and reduction of the height can be facilitated. 
     According to the inductor component  1 , because the first and the second external terminals  11  and  12  are buried in the magnetic composite body  30 , downsizing can be facilitated. 
     Example 1 
     An Example of the first embodiment will be described. The inductor component is a power inductor that is used in a step-down switching regulator for a switching frequency of 100 MHz and that has the size of 1 mm×0.5 mm and the thickness of 0.23 mm. The number of turns of the inductor including the spiral wires is 2.5 in the two-layer structure, and the inductance value thereof is about 5 nH at 100 MHz. 
     The number of turns of each of the spiral wires is set to be able to acquire the necessary inductance value matching with the switching frequency. The number of turns is set to be equal to or smaller than 5 for a switching frequency of 50 MHz to 100 MHz. 
     The spiral wire has the size of L/S/t=70/10/70 μm, and L and t are set corresponding to the chip size and the allowable current to be energized to the inductor. The interlayer pitch of the spiral wires is 10 μm that is equal to the wire pitch, and the spiral wires can densely be wound and downsizing and reduction of the height of the inductor are enabled by setting the pitch between the wires and the interlayer pitch of the spiral wires to be equal to or smaller than 10 μm to be significantly narrow. 
     Second Embodiment 
       FIG. 5  is a cross-sectional diagram of the second embodiment of the inductor component of the present disclosure. The second embodiment is different from the first embodiment only in the configuration of the composite body. Only the different configuration will be described. In the second embodiment, the same reference numerals as those of the first embodiment denote the same configurations as those of the first embodiment and will not again be described. 
     As depicted in  FIG. 5 , the composite body of an inductor component  1 A includes an insulating composite body  40  that covers the first and a second spiral wires  21  and  22 , and a magnetic composite body  30 A that covers the insulating composite body  40 . The material of the magnetic composite body  30 A is the same as the material of the magnetic composite body  30  of the first embodiment. 
     The insulating composite body  40  includes the composite material of the inorganic filler and the resin. The resin is an organic insulating material including, for example, an epoxy-based resin, bismaleimide, a liquid crystal polymer, polyimide, or the like. The average particle diameter of the inorganic filler is equal to or smaller than 5 μm. The inorganic filler is an insulating substance such as SiO 2 . Preferably, the inorganic filler is SiO 2  having the average particle diameter equal to or smaller than 0.5 μm. Preferably, the content rate of the inorganic filler is equal to or higher than 20 Vol % and equal to or lower than 70 Vol % relative to the insulating composite body  40 . 
     The insulating composite body  40  includes a hole  40   a  at the position corresponding to the inner diameter portion of each of the first and the second spiral wires  21  and  22 . The magnetic composite body  30 A is disposed in the hole  40   a  of the insulating composite body  40  that corresponds to the inner magnetic path, and on and beneath the insulating composite body  40  that corresponds to the outer magnetic paths. 
     The insulating composite body  40  includes first to third composite layers  41  to  43 . The first to the third composite layers  41  to  43  are sequentially disposed from a lower layer to an upper layer. The first spiral wire  21  is stacked on the first composite layer  41 . The second composite layer  42  is stacked on the first spiral wire  21  to cover the first spiral wire  21 . The second spiral wire  22  is stacked on the second composite layer  42 . The third composite layer  43  is stacked on the spiral wire  22  to cover the second spiral wire  22 . 
     The upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  are positioned in the same plane as that of the upper end face  30   a  of the magnetic composite body  30 A. The first and the second external terminals  11  and  12  are buried in the magnetic composite body  30 A. 
     A manufacture method of the inductor component  1 A will be described. 
     As depicted in  FIG. 6A , the base platform  50  is prepared. The base platform  50  includes the insulating substrate  51  and the 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 layer  52  is a Cu foil sheet. The thickness of the base platform  50  does not influence the thickness of the inductor component  1 A and any base platform  50  having a thickness suitable for easy handling may properly be used because of the reasons such as warpage generated in the processing. 
     As depicted in  FIG. 6B , the dummy metal layer  60  is bonded to the one face of the base platform  50 . In this embodiment, because the dummy metal layer  60  is a Cu foil sheet. Because the dummy metal layer  60  is bonded to the base metal layer  52  of the base platform  50 , the dummy metal layer  60  is bonded to the smooth face of the base metal layer  52 . The adhesive force between the dummy metal layer  60  and the base metal layer  52  can therefore be weakened and, in the post-process, the base platform can be easily peeled off from the dummy metal layer  60 . Preferably, the adhesive bonding the base platform  50  and the dummy metal layer  60  to each other is a low adhesion adhesive. To weaken the adhesive force between the base platform  50  and the dummy metal layer  60 , the bonding surface of each of the base platform  50  and the dummy metal layer  60  is advantageously a glossy surface. 
     The first composite layer  41  is thereafter stacked on the dummy metal layer  60  that is temporarily bonded to the base platform  50 . At this time, the first composite layer  41  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. A portion of the first composite layer  41  corresponding to the inner magnetic path (the magnetic core) is thereafter removed using a laser or the like to dispose an opening  41   a.    
     As depicted in  FIG. 6C , the first spiral wire  21  and the second connection wire  26  are stacked on the first composite layer  41 . The first spiral wire  21  and the second connection wire  26  are not in contact with each other. The second connection wire  26  is disposed on a side opposite to that of the outer circumference part  21   b . For example, a power supply film for the SAP (Semi Additive Process) is disposed on the first composite layer  41  using electroless plating, sputtering, vapor deposition, or the like. After disposing the power supply film, a photosensitive resist is applied or attached to the power supply film and the wire pattern is formed using photolithography. The metal wires corresponding to the wires  21  and  22  are thereafter disposed using the SAP. After disposing the metal wires, the photosensitive resist is peeled and removed using a chemical solution and the power supply film is removed by etching. Additional Cu electrolytic plating is thereafter applied using the metal wires as a power supply part, and the wires  21  and  22  each having a narrower space can thereby be acquired. A first sacrifice conductor  71  corresponding to the inner magnetic path is disposed on the dummy metal layer  60  in the opening  41   a  of the first composite layer  41 . The first sacrifice conductor  71  is disposed using the SAP. In this embodiment, the Cu wire having L (the wire width)/S (the wire space (the wire pitch))/t (the wire thickness) to be 50/30/60 μm is disposed using the SAP and a wire having L/S/t=75/5/73 μm can thereafter be acquired by executing additional Cu electrolytic plating therefor that corresponds to the thickness of 12.5 μm. 
     As depicted in  FIG. 6D , the second composite layer  42  is stacked on the first spiral wire  21  to cover the first spiral wire  21  with the second composite layer  42 . The second composite layer  42  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. At this time, the thickness of the second composite layer  42  above the first spiral wire  21  is set to be equal to or smaller than 5 μm. The interlayer pitch of the first and the second spiral wires  21  and  22  can thereby be set to be equal to or smaller than 5 μm. 
     To secure the filling property into the wire pitch (for example, 5 μm) of the first spiral wire  21 , the inorganic filler (the insulating substance) included in the second composite layer needs to have the particle diameter that is sufficiently smaller than the wire pitch of the first spiral wire  21 . To realize the reduction of the thickness of the component, the interlayer pitch for the continued wire in the upper portion needs to be reduced to be equal to or smaller than, for example, 5 μm, and the insulating substance therefore needs to also have a particle diameter that is sufficiently small. 
     As depicted in  FIG. 6E , via holes  42   b  to be filled with the via wires  27  are disposed in the second composite layer  42  using laser processing or the like. A portion of the second composite layer  42  corresponding to the inner magnetic path (the magnetic core) is removed using a laser or the like and an opening  42   a  is disposed. 
     As depicted in  FIG. 6F , the via holes are filled with the via wires  27  and the second spiral wire  22  and the first connection wire  25  are stacked on the second composite layer  42 . The second spiral wire  22  and the first connection wire  25  are not in contact with each other. The first connection wire  25  is disposed on a side opposite to that of the outer circumference part  22   b . At this time, the second spiral wire  22  is disposed using the same process as that for the first spiral wire  21 . A second sacrifice conductor  72  corresponding to the inner magnetic path is disposed on the first sacrifice conductor  71  in the opening  42   a  of the second composite layer  42 . At this time, the via wires  27 , the second spiral wire  22 , the first connection wire  25 , and the second sacrifice conductor  72  can be disposed using the same process as that for the first spiral wire  21 . 
     As depicted in  FIG. 6G , the third composite layer  43  is stacked on the second spiral wire  22  to cover the second spiral wire  22  with the third composite layer  43 . The third composite layer  43  is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. 
     As depicted in  FIG. 6H , a portion of the third composite layer  43  corresponding to the inner magnetic path (the magnetic core) is removed using a laser or the like to dispose an opening  43   a.    
     The base platform  50  is thereafter peeled off from the dummy metal layer  60  in the adhesion surface between the one face of the base platform  50  (the base metal layer  52 ) and the dummy metal layer  60 . The dummy metal layer  60  is removed by etching or the like, the first and the second sacrifice conductors  71  and  72  are removed by etching or the like, and, as depicted in  FIG. 6I , a hole  40   a  corresponding to the inner magnetic path is disposed in the insulating composite body  40 . Via holes  43   b  to be filled with the via wires  27  are thereafter disposed in the third composite layer  43  using laser processing or the like. The via holes  43   b  are filled with the via wires  27 , and the first and the second external terminals  11  and  12  each having a columnar shape are stacked on the third composite layer  43 . At this time, the via wires  27 , and the first and the second external terminals  11  and  12  can be disposed using the same process as that for the first spiral wire  21 . 
     As depicted in  FIG. 6J , the first and the second external terminals  11  and  12 , and the insulating composite body  40  are covered with the magnetic composite body  30 A, and an inductor substrate  5 A is thereby formed. The magnetic composite body  30 A is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. The magnetic composite body  30 A also fills the hole  40   a  of the insulating composite body  40 . 
     As depicted in  FIG. 6K , the magnetic composite body  30 A on and beneath the inductor substrate  5 A is processed to be a thin film using a grinding process. At this time, a portion of each of the first and the second external terminals  11  and  12  is exposed and upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  are thereby positioned in the same plane as that of the upper end face  30   a  of the magnetic composite body  30 A. In this case, reduction of the thickness of the component can be facilitated by grinding the magnetic composite body  30 A to have a thickness that is sufficient to be able to acquire an inductance value. For example, in this embodiment, the thickness thereof can be set to be 35 μm. 
     The inductor substrate  5 A is thereafter divided into individual chips by dicing and scribing to form the inductor components  1 A each depicted in  FIG. 5 . After the division into individual chips, a plating film of NiSn or the like may be applied to the first and the second external terminals  11  and  12  using a method such as barrel plating to enhance the mounting property thereof. 
     Though the inductor substrate  5 A is disposed on one face of both faces of the base platform  50 , the inductor substrate  5 A may be disposed on each of both faces of the base platform  50 . High productivity can thereby be achieved. 
     According to the inductor component  1 A, because the composite body includes the insulating composite body  40  and the magnetic composite body  30 A, the insulation between the wires and the interlayer insulation of the first and the second spiral wires  21  and  22  can be secured by the insulating composite body  40 , and a high inductance value can be acquired due to the magnetic composite body  30 A. 
     According to the inductor component  1 A, the inorganic filler of the insulating composite body  40  is SiO 2  having the average particle diameter equal to or smaller than 0.5 μm, the insulation between the wires and the interlayer insulation of the first and the second spiral wires  21  and  22  can therefore be enhanced, and downsizing and reduction of the height can further be facilitated. Compared to the first embodiment, the insulation between the wires and the interlayer insulation can further be enhanced by employing the insulating substance as the inorganic filler, and the wire pitch of the first and the second spiral wires  21  and  22 , and the interlayer pitch can therefore be reduced. 
     According to the inductor component  1 A, because the content rate of the inorganic filler of the insulating composite body  40  is equal to or higher than 20 Vol % and equal to or lower than 70 Vol %, the fluidity and the insulation can concurrently be established. 
     Example 2 
     An Example of the second embodiment will be described. The inductor component is a power inductor that is used as a use thereof in a step-down switching regulator for a switching frequency of 100 MHz and that has the size of 1 mm×0.5 mm and the thickness of 0.23 mm. The number of turns of each of the spiral wires is 2.5 in the two-layer structure, and the inductance value thereof is about 5 nH at 100 MHz. 
     The number of turns of each of the spiral wires is set to be able to acquire the necessary inductance value matching with the switching frequency. The number of turns is set to be equal to or smaller than 10 for a switching frequency of 40 MHz to 100 MHz. 
     Though the Example is depicted that includes the spiral wire whose L/S/t is L/S/t=75/5/73 μm, L and t are set corresponding to the chip size and the allowable current to be energized to the inductor. The interlayer pitch of the spiral wires is 5 μm that is equal to the wire pitch, and the spiral wires can densely be wound and downsizing and reduction of the height of the inductor are enabled by setting the wire pitch and the interlayer pitch of the spiral wires to be equal to or smaller than 10 μm to significantly be narrow. 
     Third Embodiment 
       FIG. 7  is a cross-sectional diagram of the third embodiment of the inductor component of the present disclosure. The third embodiment is different from the second embodiment only in the quantity of the external terminals, and copes with incorporation thereof into a package substrate. Only the different configuration will be described. In the third embodiment, the same reference numerals as those of the second embodiment denote the same configurations as those of the second embodiment and will not again be described. 
     As depicted in  FIG. 7 , in an inductor component  1 B, the external terminals  11  to  14  are disposed both over and under the first and the second spiral wires  21  and  22  in the stacking direction. The inductor component  1 B includes the third and the fourth external terminals  13  and  14  in addition to the first and the second external terminals  11  and  12  of the second embodiment. 
     The third and the fourth external terminals  13  and  14  are disposed under the first and the second spiral wires  21  and  22  in the stacking direction. The third external terminal  13  faces the first external terminal  11  and is electrically connected to the first external terminal  11  through the via wire  27 . The fourth external terminal  14  faces the second external terminal  12  and is electrically connected to the second external terminal  12  through the via wire  27 . 
     Lower end faces  13   a  and  14   a  of the third and the fourth external terminals  13  and  14  in the stacking direction are positioned in the same plane as that of a lower end face  30   b  of the magnetic composite body  30 A in the stacking direction. The third and the fourth external terminals  13  and  14  are buried in the magnetic composite body  30 A. 
     A manufacture method of the inductor component  1 B will be described. 
     A method is executed that is the same as the method depicted in  FIG. 6A  to  FIG. 6H  of the second embodiment. 
     As depicted in  FIG. 8A , the hole  40   a  corresponding to the inner magnetic path is disposed in the insulating composite body  40 . The via holes  43   b  in the upper and the lower face of the insulating composite body  40  are filled with the via wires  27 . The first and the second external terminals  11  and  12  each having a columnar shape are disposed on the upper face of the third composite layer  43 , and the third and the fourth external terminals  13  and  14  each having a columnar shape are disposed on the lower face of the first composite layer  41 . In this case, the via wires  27  and the first, the second, the third, and the fourth external terminals  11 ,  12 ,  13 , and  14  can be disposed using the same process as that for the first spiral wire  21 . 
     As depicted in  FIG. 8B , the first to the fourth external terminals  11  to  14  and the insulating composite body  40  are covered with the magnetic composite body  30 A and the inductor substrate  5 B is thereby formed. The magnetic composite body  30 A is thermally compressed and thermally cured using a vacuum laminator, a pressing machine, or the like. The hole  40   a  of the insulating composite body  40  is also filled with the magnetic composite body  30 A. 
     As depicted in  FIG. 8C , the magnetic composite body  30 A on and under the inductor substrate  5 B is processed to be a thin film using a grinding process. In this case, a portion of each of the first to the fourth external terminals  11  to  14  is exposed, the upper end faces  11   a  and  12   a  of the first and the second external terminals  11  and  12  are thereby positioned in the same plane as that of the upper end face  30   a  of the magnetic composite body  30 A, and the lower end faces  13   a  and  14   a  of the third and the fourth external terminals  13  and  14  are thereby positioned in the same plane as that of the lower end face  30   b  of the magnetic composite body  30 A. In this case, reduction of the thickness of the component can be facilitated by grinding the magnetic composite body  30  to have a thickness that is sufficient to be able to acquire an inductance value. 
     The inductor substrate  5 B is thereafter divided into individual chips by dicing and scribing to form the inductor components  1 B each depicted in  FIG. 7 . After the division into individual chips, a plating film of NiSn or the like may be applied to the first and the second external terminals  11  and  12  using a method such as barrel plating to enhance the mounting property thereof. 
     Though the inductor substrate  5 B is formed on one face of both faces of the base platform  50 , the inductor substrate  5 B may be formed on each of both faces of the base platform  50 . High productivity can thereby be achieved. 
     According to the inductor component  1 B, because the external terminals  11  to  14  are disposed both over and under the spiral wires  11  and  12  in the stacking direction, wires conductive for the external terminals  11  to  14  on and beneath the inductor component  1 B can be disposed on the upper and the lower faces of the substrate when the inductor component  1 B is buried in the substrate. The output side of the chopper circuit branched into two directions that are the side to connect the load and the ground side through the smoothing capacitor can therefore be connected to each other in the shortest course without running any more wire around, by the upper and the lower external terminals that are electrically connected to each other. The ESR and the ESL of the smoothing capacitor on the output side can therefore be reduced and the ripple voltage of the output can be reduced. 
     Because the two terminals are used only for the external terminals on the output side as above, the external terminal on the input side may be one and, for example, either the external terminal  13  or  14  does not need to be disposed in the inductor component  1 B. Disposing both of the external terminals  13  and  14  can however improve the symmetry in the inductor component  1 B, and can facilitate reduction of asymmetry of the property, improvement of the degree of freedom of wiring, improvement of co-planarity of the overall component, and the like. 
     Example 3 
     An Example of the third embodiment will be described. The inductor component is a power inductor that is used as a use thereof in a step-down switching regulator for a switching frequency of 100 MHz and that has the size of 1 mm×0.5 mm and the thickness of 0.23 mm. The number of turns of each of the spiral wires is 2.5 in the two-layer structure, and the inductance value thereof is about 5 nH at 100 MHz. 
     Fourth Embodiment 
       FIG. 9  is a cross-sectional diagram of one embodiment of the package component of the present disclosure. In the fourth embodiment, the same reference numerals as those of the third embodiment denote the same configurations as those of the third embodiment and will not again be described. 
     As depicted in  FIG. 9 , the package component  2  is a module that includes a substrate in an IC package and includes the substrate  80  and the inductor component  1 B of the third embodiment that is buried in the substrate  80 . The substrate  80  includes, for example, FR4, CES3, or the like. The first and the second external terminals  11  and  12  on the upper side of the inductor component  1 B are disposed on the side of an upper face  80   a  of the substrate  80 . The third and the fourth external terminals  13  and  14  on the lower side of the inductor component  1 B are disposed on the side of a lower face  80   b  of the substrate  80 . 
     Wires  81  and  82  are disposed on the upper face  80   a  of the substrate  80  through an insulating resin  85 . The first wire  81  is electrically connected to the first external terminal  11  through an opening of the insulating resin  85 . The second wire  82  is electrically connected to the second external terminal  12  through an opening of the insulating resin  85 . 
     Wires  83  and  84  are disposed on the lower face  80   b  of the substrate  80  through the insulating resin  85 . The third wire  83  is electrically connected to the third external terminal  13  through an opening of the insulating resin  85 . The fourth wire  84  is not electrically connected to any of the external terminals  11  to  14 . 
     A manufacture method of the package component  2  will be described. 
     As depicted in  FIG. 10A , the substrate  80  is prepared. For example, a thin substrate having a thickness of 0.33 mm, 0.23 mm, or the like is used as the substrate  80  for downsizing and reduction of the height of the IC. 
     As depicted in  FIG. 10B , a penetrating hole  80   c  is disposed in the substrate  80  using a drill, a laser, or the like. 
     As depicted in  FIG. 10C , a temporary attachment tape  86  with low adhesion is attached to the lower face  80   b  of the substrate  80 . A thermally foamed sheet or the like may be used instead of the temporary attachment tape  86 . 
     As depicted in  FIG. 10D , the inductor component  1 B is installed in the penetrating hole  80   c . The insulating resin  85  such as a build-up sheet, a pre-preg, or the like is thereafter laminated on the upper face  80   a  of the substrate  80 , the inductor component  1 B and the substrate  80  are sealed, and the temporary attachment tape  86  is removed. 
     As depicted in  FIG. 10E , the insulating resin  85  is laminated on the lower face  80   b  of the substrate  80 , the insulating resins  85  are thereafter thermally cured, and the substrate  80  having the inductor component  1 B buried therein is acquired. 
     As depicted in  FIG. 10F , via holes are disposed using a laser in the portions of the insulating resins  85  to be contact points between the external terminals  11  to  13  of the inductor component  1 B and the circuit. In this case, because the surface of the magnetic composite body  30 A and the surfaces of the external terminals  11  to  13  are disposed on the same smooth plane, defective processing due to out-of-focus laser processing and the like tend to be avoided and the productivity can be improved. The smear caused by the laser is thereafter removed and wiring layers  87  are disposed using an approach such as electroless plating or electrolytic plating. 
     Etching processing is applied to the wiring layers  87  using resist patterns and the like to dispose the necessary lands and wires on the substrate  80  and, as depicted in  FIG. 9 , the package component  2  can be acquired. 
     According to the package component  2 , the inductor component  1 B is buried in the substrate  80 , the wires  81  and  82  electrically connected to the external terminals  11  and  12  on the upper side are disposed on the upper face  80   a  of the substrate  80 , and the wire  83  electrically connected to the external terminal  13  on the lower side is disposed on the lower face  80   b  of the substrate  80 . The output side of the chopper circuit can be connected in the shortest course without running any more wire around using the external terminals  11  and  13  on the upper and the lower sides electrically connected to each other. The ESR and the ESL of the smoothing capacitor on the output side can therefore be reduced and the ripple voltage of the output can be reduced. 
     Fifth Embodiment 
       FIG. 11A  is a cross-sectional diagram of one embodiment of a switching regulator of the present disclosure.  FIG. 11B  is an equivalent circuit diagram of the switching regulator. In the fifth embodiment, the same reference numerals as those of the fourth embodiment denote the same configurations as those of the fourth embodiment and will not again be described. 
     As depicted in  FIG. 11A  and  FIG. 11B , the switching regulator  3  plays the role of a voltage regulator (VR) that converts a power source voltage from an external power source (not depicted) into a voltage suitable for a central processing unit  121  and that supplies the converted voltage to the central processing unit  121 . 
     The switching regulator  3  includes the package component  2  of the fourth embodiment, a switching element  123   a  that opens or closes the electric connection between the external power source and the inductor component  1 B, and a smoothing capacitor  90  that smoothes the output voltage from the inductor component  1 B. 
     The switching element  123   a  is disposed on the side of the upper face  80   a  of the substrate  80  of the package component  2  and is electrically connected to the second wire  82  connected to the external terminal  12  of the other (on the input side) of the pair (on the input and the output sides) of external terminals. The smoothing capacitor  90  is disposed on the side of the lower face  80   b  of the substrate  80  of the package component  2  and is electrically connected to the wire  83  on the lower side of the wires  81  and  83  connected to the external terminals  11  and  13  of the one (on the output side) of the pair (on the input and the output sides) of external terminals. The wire  81  on the upper side is the output terminal, of the wires  81  and  83  connected to the external terminals  11  and  13  of the one (on the output side) of the pair (on the input and the output sides) of external terminals. 
     A voltage regulating part  123  and the central processing unit  121  are integrated in one IC chip  120 . The IC chip  120  is mounted on the upper face  80   a  of the substrate  80  of the package component  2 . The voltage regulating part  123  includes the switching element  123   a  and a driver  123   b  that drives the switching element  123   a . The switching element  123   a  is connected to the second wire  82  of the package component  2  through an internal connection electrode  91 . The central processing unit  121  is connected to the first wire  81  of the package component  2  through the internal connection electrode  91 . 
     The smoothing capacitor  90  is mounted on the lower face  80   b  of the substrate  80  of the package component  2 . An input part of the smoothing capacitor  90  is connected to the third wire  83  of the package component  2 . An output part of the smoothing capacitor  90  is connected to the fourth wire  84  of the package component  2 . The fourth wire  84  is connected to the ground through an external connection electrode  92 . 
     As above, the switching element  123   a  is connected to the input part of the inductor component  1 B, and the central processing unit  121  and the smoothing capacitor  90  are connected to the output part of the inductor component  1 B. Though not depicted, the IC chip  120  and the substrate  80  are integrated with each other by a molded-in epoxy resin or the like to constitute one single IC package. 
     According to the switching regulator  3 , the smoothing capacitor  90  is connected to the wires  83  and  84  on the lower face  80   b  of the substrate  80  of the package component  2 , and the switching element  123   a  and the central processing unit  121  are connected to the wires  81  and  82  on the upper face  80   a  of the substrate  80  of the package component  2 . The inductor component  1 B of the package component  2 , and the central processing unit  121  and the smoothing capacitor  90  can thereby be connected to each other in the shortest course without running any more wire around, by the first and the third external terminals  11  and  13  in the upper and the lower portions. The ESR and the ESL of the smoothing capacitor  90  can therefore be reduced and the ripple voltage of the output can be reduced. A load other than the central processing unit  121  may be connected to the first wire  81  to be the output terminal. 
     The present disclosure is not limited to the embodiments and their designs can be changed within the scope not departing from the gist of the present disclosure. For example, the features of each of the first to the fifth embodiments may variously be combined with each other. Though the inductor component includes the spiral wires in the two layers in the embodiments, the inductor component may include spiral wires in three or more layers. 
     Though the number of inductors including the spiral wires is one in the embodiments, the number of inductors included in the inductor component is not limited to one. For example, spiral wires having plural spirals in one same plane may configure plural inductors.