JP2013225718A - Manufacturing method of coil component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a small-sized, thin-type and high-performance coil component in which a DC superposition property is improved and it is not necessary to form a magnetic gap.SOLUTION: A manufacturing method of a coil component includes the steps for forming spiral conductors 12 and 13 on a principal surface of an insulation substrate 11, forming an upper core 15 and a lower core 16, respectively, covering one and the other principal surfaces of the insulation substrate 11 and dicing the insulation substrate 11 together with the upper core 15 and the lower core 16. The step for forming the upper core 15 includes a step for forming connecting parts 11h and 15a-15d which are individually disposed in the center and four corners of a rectangular area on the insulation substrate 11 including the spiral conductors 12 and 13 and physically connect the upper core 15 and the lower core 16. The step for forming the connecting parts includes a step for burying a metal magnetic powder containing resin within an opening pattern formed outside of the center of the rectangular area and positions where the spiral conductors are formed, and then dicing the metal magnetic powder containing resin together with the insulation substrate 11.

Description

  The present invention relates to a method for manufacturing a coil component, and more particularly to a method for manufacturing a coil component that is preferably used as a power supply inductance.

  Surface mount type coil components are widely used in consumer or industrial electronic devices. In particular, in small portable devices, it is necessary to obtain a plurality of voltages from a single power source in order to drive various devices as functions are enhanced. Such coil components for power supply are required to be small and thin, have excellent electrical insulation and reliability, and can be manufactured at low cost.

  As a structure of a coil component that satisfies the above requirements, a planar coil structure using a printed circuit board circuit technique is known. This type of coil component has a structure in which a planar coil pattern is formed on the front and back surfaces of a printed circuit board, and the printed circuit board is sandwiched between, for example, EE type or EI type sintered ferrite cores. A closed magnetic circuit is formed around the pattern.

  Coil parts for power supplies are required to have an inductance that does not decrease due to magnetic saturation even when a large DC bias current is applied. Therefore, the coil component described in Patent Document 1 includes a first magnetic layer that covers the upper surface of the insulating substrate on which the planar coil pattern is formed, and a second magnetic layer that covers the lower surface, and these two resin layers are formed of the coil pattern. The outer edge region has a structure having a gap in the thickness direction. Therefore, magnetic saturation of the magnetic circuit can be suppressed and the inductance can be increased.

  Patent Document 2 discloses a coil component in which an air-core coil is embedded in an exterior resin and integrated. This coil component uses a resin containing metal magnetic powder, and in particular, by using a composite material in which two or more kinds of amorphous metal magnetic powders having different average particle diameters and an insulating binder are mixed, High magnetic permeability and low core loss can be obtained even under low pressure molding.

JP 2006-310716 A JP 2010-034102 A

  However, in the conventional coil component disclosed in Patent Document 1, it is necessary to provide a gap in order to increase the inductance, but there is a problem that adjustment of the gap width is very difficult for reasons of assembly accuracy and processing accuracy. is there.

  Moreover, although the conventional coil component described in Patent Document 2 uses a resin containing metal magnetic powder as a core material, it is very large because an air-core coil using windings is used. Moreover, it is difficult to keep the shape of the coil constant, and there is a problem that variations in the inner diameter of the coil and the position of the air-core coil are large.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for producing a high-performance coil component that has good direct current superposition characteristics and does not require the formation of a magnetic gap. . Another object of the present invention is to provide a method for manufacturing a small and thin coil component with high dimensional processing accuracy.

  In order to solve the above problems, a method for manufacturing a coil component according to the present invention includes a step of forming a spiral conductor on at least one main surface of an insulating substrate, and a metal magnetic powder-containing resin that covers the one main surface of the insulating substrate. A step of forming an upper core comprising: a step of forming a lower core made of the metal magnetic powder-containing resin covering the other main surface of the insulating substrate; and the insulating substrate together with the upper core and the lower core. And at least one of the step of forming the upper core and the step of forming the lower core is made of the metal magnetic powder-containing resin and includes a rectangular region on the insulating substrate including the spiral conductor. Forming a connecting portion that is individually disposed at each of the central portion and the four corners to physically connect the upper core and the lower core; A step of forming an opening pattern penetrating the insulating substrate outside a formation portion of the rectangular region and the spiral conductor, and a step of embedding the metal magnetic powder-containing resin in the opening pattern And dicing the metal magnetic powder-containing resin embedded in the opening pattern together with the insulating substrate.

  According to the present invention, since the magnetic magnetic powder-containing resin is used as the material of the closed magnetic circuit, the saturation magnetic flux density can be increased without forming a gap like a ferrite core, and high-precision machining is performed. Thus, a small and thin coil component can be manufactured. In particular, since the connecting portions at the four corners of the insulating substrate completely connect the upper core and the lower core, a closed magnetic circuit without a gap can be formed. In addition, by forming closed magnetic paths at the four corners, the loop size of the spiral conductor can be increased, and the resistance, high inductance, and size of the coil can be reduced. Furthermore, since the metal magnetic powder-containing resin is diced together with the insulating substrate, the outer side surface of the connecting portion and the side surface of the insulating substrate can be flush with each other. Thus, a magnetic path can be formed in the outer shape of the insulating substrate without any gap with the substrate.

  In the present invention, the opening pattern is preferably a substantially circular pattern formed at each of a central portion and four corners of the rectangular region. In this case, it is preferable that the inner side surface of the four corner connecting portion in contact with the side surface of the insulating substrate is a curved surface that swells toward the center of the insulating substrate, and the planar shape of the four corner connecting portion is substantially a quarter circle. It is particularly preferred that According to this, the drilling process can be facilitated and the metal magnetic powder-containing resin can be filled smoothly to every corner.

  The coil component according to the present invention includes at least one insulating substrate, a spiral conductor formed on at least one main surface of the insulating substrate, an upper core covering the one main surface of the insulating substrate, and the insulation. A lower core covering the other main surface of the substrate, wherein at least one of the upper core and the lower core is made of a metal magnetic powder-containing resin, and is disposed on a central portion and an outer side of the insulating substrate. And a connecting portion for physically connecting the lower core.

  According to the present invention, the metal magnetic powder-containing resin is used as the material of the closed magnetic circuit, so that the resin exists between the metal magnetic powders, and a minute gap is formed, thereby increasing the saturation magnetic flux density. It is not necessary to form a gap like a ferrite core. Therefore, highly accurate machining is not required, and a small and thin coil component can be provided.

  In the present invention, it is preferable that both the upper core and the lower core are made of the metal magnetic powder-containing resin. According to this configuration, since the entire magnetic core is a metal magnetic powder-containing resin, it is possible to provide a coil component having sufficiently high DC superposition characteristics.

  In the present invention, it is preferable that one of the upper core and the lower core is made of the metal magnetic powder-containing resin and the other is made of a ferrite substrate. According to this configuration, since the metal magnetic powder-containing resin paste can be applied using the ferrite substrate as the support substrate, it is easy to form a magnetic core using the metal magnetic powder-containing resin. In addition, since the saturation magnetic flux density is sufficiently increased by one magnetic core, even if the other is a ferrite substrate, it is possible to provide a coil component having high DC superposition characteristics without forming a gap.

  In this invention, it is preferable that the said connection part which connects the said upper core and the said lower core is arrange | positioned at the four corners of the said insulated substrate. When the closed magnetic circuit is formed at the four corners of the insulating substrate, the formation area of the spiral conductor can be widened and the loop size can be increased. Therefore, the resistance of the coil can be reduced, the inductance can be increased, and the size can be reduced. Furthermore, the connecting portion can be formed using a relatively wide blank area where the spiral conductor is not formed, and the cross-sectional area of the closed magnetic circuit can be increased.

  In the case where the connecting portions that connect the upper core and the lower core are disposed at the four corners of the insulating substrate, the connecting portions at the four corners may be provided in contact with the edges of the corner portions of the insulating substrate. The insulating substrate may be provided on the inner side than the edge of the corner portion. When the four corners are in contact with the edges of the corners of the insulating substrate, a common connecting part is formed in four adjacent chips at the time of mass production. It can be formed and is easy to process. In addition, when the connecting portions at the four corners are on the inner side of the edge of the corner portion of the insulating substrate, a plating conductor pattern to be described later can be easily arranged.

  The coil component according to the present invention further includes a plating conductor pattern formed on the one main surface of the insulating substrate, and one end of the plating conductor pattern is electrically connected to the spiral conductor, and the plating conductor The other end of the pattern extends to the edge of the insulating substrate, and the plating conductor pattern electrically connects the spiral conductors of adjacent coil components in mass production where a plurality of coil components are formed on the same substrate. It is preferable to constitute a part of the short-circuit pattern to be connected. According to this configuration, the conductive patterns of a plurality of adjacent chips can be collectively plated, and the manufacturing process can be made more efficient.

  The coil component according to the present invention further includes a pair of terminal electrodes provided on an outer peripheral surface of the laminate including the insulating substrate, the upper core, and the lower core, and an insulating coating that covers the surfaces of the upper core and the lower core. It is preferable that the insulating coating is interposed between the pair of terminal electrodes and the upper core and the lower core. In this case, the insulating coating is preferably an insulating layer subjected to chemical conversion treatment using iron phosphate, zinc phosphate or zirconia dispersion. According to this configuration, it is possible to ensure insulation between the pair of terminal electrodes.

  In the present invention, the insulating coating is preferably made of a nickel-based ferrite powder-containing resin. According to this structure, an insulating film can be functioned as a part of closed magnetic circuit.

  The coil component according to the present invention includes a plurality of the insulating substrates, and the plurality of insulating substrates are stacked without substantially interposing the metal magnetic powder-containing resin, and the spiral conductor formed on each insulating substrate. It is preferable that they are connected in parallel or in series through the pair of terminal electrodes. Although there is a limit to the cross-sectional area of the spiral conductor that can be formed on the insulating substrate, the spiral conductor can be substantially cut off by stacking multiple insulating substrates and connecting the spiral conductors on each insulating substrate in parallel. The configuration is equivalent to increasing the area. In addition, by connecting the spiral conductors on each insulating substrate in series, the number of coil turns required for one substrate is reduced, so that the line width and thickness of the spiral conductor can be increased. Therefore, the cross-sectional area of the spiral conductor can be sufficiently increased. Therefore, the DC resistance of the coil component can be reduced.

  According to the present invention, it is possible to provide a high-performance coil component that has good direct current superposition characteristics and does not require the formation of a magnetic gap. In addition, according to the present invention, it is possible to provide a small and thin coil component with high dimensional processing accuracy.

1 is a schematic exploded perspective view showing a structure of a coil component 10 according to a first embodiment of the present invention. It is a schematic plan view of the coil component 10 shown in FIG. FIG. 3 is a schematic cross-sectional side view of the coil component 10 of FIG. 2, where (a) is a cross-sectional view taken along line XX of FIG. 2, and (b) is a cross-sectional view taken along line YY of FIG. . It is a figure which shows the manufacturing process of the coil component 10, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view. It is a figure which shows the manufacturing process of the coil component 10, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view. It is a figure which shows the manufacturing process of the coil component 10, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view. It is a figure which shows the manufacturing process of the coil component 10, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view. It is a schematic side sectional view showing the configuration of the coil component 20 according to the second embodiment of the present invention. It is a schematic plan view which shows the structure of the coil component 30 by the 3rd Embodiment of this invention. 5 is a schematic plan view showing a manufacturing process of the coil component 30. FIG. It is a schematic plan view which shows the structure of the coil component 40 by the 4th Embodiment of this invention. FIG. 9 is a schematic side sectional view showing the configuration of a coil component 50 according to a fifth embodiment of the present invention. It is a figure which shows the manufacturing process of the coil component 50, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view. 5 is a schematic side sectional view showing a manufacturing process of the coil component 50. FIG. It is a schematic sectional side view which shows the structure of the coil component 60 by the 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the coil component 70 by the 7th Embodiment of this invention, Comprising: (a) has shown 3 terminal structure, (b) has each shown 4 terminal structure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic exploded perspective view showing the structure of the coil component 10 according to the first embodiment of the present invention. 2 is a schematic plan view of the coil component 10 shown in FIG. 1, and FIG. 3 is a schematic side sectional view of the coil component 10 taken along lines XX and YY in FIG.

  As shown in FIGS. 1 to 3, the coil component 10 according to the first embodiment includes an insulating substrate 11, a first spiral conductor 12 formed on one main surface (upper surface 11 a) of the insulating substrate 11, A second spiral conductor 13 formed on the other main surface (back surface 11 b) of the insulating substrate 11, insulating resin layers 14 a and 14 b covering the first and second spiral conductors 12 and 13, respectively; An upper core 15 covering the upper surface 11a side, a lower core 16 covering the back surface 11b side of the insulating substrate 11, and a pair of terminal electrodes 17a and 17b are provided.

  The insulating substrate 11 serves as a lower ground for forming the first and second spiral conductors 12 and 13. The insulating substrate 11 has a rectangular shape, and has a circular opening 11h at the center. The material of the insulating substrate 11 is preferably a general printed circuit board material in which a glass cloth is impregnated with an epoxy resin. For example, a BT base material, an FR4 base material, an FR5 base material, or the like can be used. When the printed circuit board material is used, the spiral conductor can be formed by plating instead of sputtering in a so-called thin film method, so that the thickness of the conductor can be sufficiently increased. In order to avoid an increase in stray capacitance, the dielectric constant of the insulating substrate 11 is preferably 7 or less (μ ≦ 7). Although not particularly limited, the dimension of the insulating substrate 11 can be set to, for example, 2.5 × 2.0 × 0.3 mm.

  The first and second spiral conductors 12 and 13 are circular spirals and are arranged so as to surround the opening 11 h of the insulating substrate 11. The first and second spiral conductors 12 and 13 are generally overlapped in plan view, but are not completely matched. That is, the first spiral conductor 12 viewed from the upper surface 11a side of the insulating substrate 11 forms a counterclockwise spiral from the outer peripheral end 12b toward the inner peripheral end 12a, and is viewed from the upper surface 11a side of the insulating substrate 11. The second spiral conductor 13 forms a counterclockwise spiral from the inner peripheral end 13a to the outer peripheral end 13b. As a result, the directions of the magnetic fluxes generated by the current flowing through the spiral conductors 12 and 13 coincide with each other, and the magnetic fluxes generated by the spiral conductors 12 and 13 overlap and strengthen each other, so that a large inductance can be obtained.

  A pair of terminal electrodes 17a and 17b are respectively provided on two opposing side surfaces 18a and 18b of the laminate composed of the insulating substrate 11, the upper core 15 and the lower core 16. The outer peripheral end 12b of the first spiral conductor 12 is drawn out to the first side face 18a and connected to one terminal electrode 17a. The outer peripheral end 13b of the second spiral conductor 13 is drawn to the second side face 18b and connected to the other terminal electrode 17b. Further, the inner peripheral end 12 a of the first spiral conductor 12 and the inner peripheral end 13 a of the second spiral conductor 13 are connected to each other through a through-hole conductor 11 i that penetrates the insulating substrate 11. Thereby, the 1st and 2nd spiral conductors 12 and 13 comprise the single coil mutually connected in series.

  As the material of the first and second spiral conductors 12 and 13, it is preferable to use Cu which has high conductivity and can be easily processed. Although not particularly limited, the spiral conductors 12 and 13 may have a width of 70 μm, a height of 120 μm, and a pitch of 10 μm. Such spiral conductors 12 and 13 are preferably formed by plating. When the spiral conductors 12 and 13 are formed by plating, the aspect ratio can be increased, and a coil having a relatively large cross-sectional area and a small DC resistance can be formed.

  The upper core 15 and the lower core 16 are made of a metal magnetic powder-containing resin. In the present embodiment, since the upper core 15 and the lower core 16 are made of the same material and are integrally formed, the boundary between them is not clear in appearance. Also, it is assumed that it is an E-type core including a columnar portion (connecting portion) protruding downward, and the lower core 16 is an I-type core composed of a plate-like portion.

  The upper core 15 is connected to the lower core 16 through a connecting portion 15a provided at the center of the rectangular planar region and two connecting portions 15b provided along two opposing side surfaces 18c and 18d. Thereby, a complete closed magnetic circuit is formed. That is, the connecting portions 15a and 15b penetrate the insulating substrate 11 and the insulating resin layers 14a and 14b, and there is no gap in the closed magnetic circuit. When a sintered ferrite core is used, a gap must be provided so that magnetic saturation does not occur even when a current is applied to a certain extent. However, when a resin containing metal magnetic powder is used, there is resin between the metal magnetic powders. Since the saturation magnetic flux density is increased by forming a minute gap, magnetic saturation can be prevented without forming an air gap between the upper core 15 and the lower core 16. Therefore, it is not necessary to machine the magnetic core with high accuracy to form the gap.

  The metal magnetic powder-containing resin is a magnetic material in which metal magnetic powder is mixed into the resin. As the metal magnetic powder, it is preferable to use a permalloy material. Specifically, a Pb—Ni—Co alloy having an average particle diameter of 20 to 50 μm is used as the first metal magnetic powder, and carbonyl iron having an average particle diameter of 3 to 10 μm is used as the second metal magnetic powder. It is preferable to use a metal magnetic powder containing these at a predetermined ratio, for example, a weight ratio of 70:30 to 80:20, preferably 75:25. The content of the metal magnetic powder is preferably 90 to 96% by weight. If the amount of metal magnetic powder is reduced relative to the resin, the saturation magnetic flux density decreases. Conversely, if the amount of metal magnetic powder is increased, the saturation magnetic flux density increases. Can be adjusted.

  Further, as the metal magnetic powder, the first metal magnetic powder having an average particle diameter of 5 μm and the second metal magnetic powder having an average particle diameter of 50 μm are mixed at a predetermined ratio, for example, 75:25. It is particularly preferable that As described above, when two types of metal magnetic powders having different particle sizes are used, a high-density magnetic core can be formed under low pressure or non-pressure forming, and high magnetic permeability and low loss can be obtained. A magnetic core can be realized.

  The resin contained in the metal magnetic powder-containing resin functions as an insulating binder. As the resin material, liquid epoxy resin or powder epoxy resin is preferably used. The resin content is preferably 4 to 10% by weight.

  The upper core 15 and the lower core 16 preferably have the same thickness, and the total thickness is preferably 0.3 to 1.2 mm. This is because if the total thickness of the upper core 15 and the lower core 16 is less than 0.3 mm, not only the mechanical strength of the component but also the inductance of the coil is reduced, and if it is thicker than 1.2 mm, the component becomes thicker. This is because the inductance is saturated and does not become so large.

  In the present embodiment, an insulating coating 19 is preferably formed on the surfaces of the upper core 15 and the lower core 16. The insulating coating 19 can be formed by chemical conversion treatment, and it is preferable to use iron phosphate, zinc phosphate or zirconia for chemical conversion treatment. As described above, when a metal magnetic powder-containing resin is used as a material for constituting a closed magnetic circuit, the metal magnetic powder is a conductor, so that insulation between the terminal electrodes 17a and 17b becomes a problem. However, according to the present embodiment, since the surface of the metal magnetic powder-containing resin is covered with insulation, sufficient insulation between the terminal electrodes 17a and 17b can be ensured.

  4-7 is a figure which shows the manufacturing process of the coil component 10, Comprising: (a) is a schematic plan view, (b) is a schematic sectional side view.

  As shown in FIGS. 4A and 4B, in the manufacture of the coil component 10, so-called mass production in which a large number (four in this case) of coil components are formed on one large insulating substrate (collective substrate). The process is carried out. Specifically, first, slits 11g, openings 11h, and through holes 11i are formed at predetermined positions on the large insulating substrate 11, and then the first and second spiral conductors 12, 13 are formed on the upper surface 11a and the rear surface 11b of the insulating substrate 11. Respectively. In the present embodiment, the spiral conductors 12 and 13 are formed by plating. Specifically, a Cu base film is formed on substantially the entire surface of the insulating substrate 11 by electroless plating. At this time, a Cu film is formed inside the through hole 11i. Thereafter, an opening pattern (negative pattern) having the same shape as the spiral conductors 12 and 13 is formed by exposing and developing the photoresist.

  Next, a thick Cu film is formed on the Cu base film by performing electroplating using the resist pattern as a mask. Thereafter, the resist is removed, and the base film is removed by etching, leaving only the spiral conductor. Thus, an insulating substrate on which the spiral conductor is formed (hereinafter referred to as a TFC (Thin Film Coil) substrate 21) is completed.

  Next, as shown in FIGS. 5A and 5B, after the insulating resin layers 14a and 14b are respectively formed on both surfaces of the TFC substrate 21, the back surface of the TFC substrate 21 is pasted on the UV tape 22. Fix it. A heat release tape may be used instead of the UV tape. By this fixing, the warpage of the TFC substrate 21 can be suppressed. Next, the metal magnetic powder-containing resin paste 15p is screen-printed on the surface side of the TFC substrate 21 to which the UV tape 22 is not attached. Although not particularly limited, the thickness of the screen sheet is about 0.27 mm. After this screen printing, defoaming is performed, and the resin paste is temporarily cured by heating at 80 ° C. for 30 minutes.

  Next, as shown in FIGS. 6A and 6B, after the TFC substrate 21 is turned upside down, the UV tape 22 is peeled off, and the metal magnetic powder-containing resin paste 16p is screened on the back side of the TFC substrate 21. Print. The thickness of the screen sheet used at this time is also 0.27 mm. Thereafter, the resin pastes 15p and 16p are fully cured by heating at 160 ° C. for 1 hour. Thus, the upper core 15 and the lower core 16 are completed.

  Next, as shown in FIGS. 7A and 7B, the coil assembly is separated into pieces by dicing the TFC substrate 21 at the positions of the cutting lines Cx and Cy. Thereafter, the insulating coating 19 is formed on the surfaces of the upper core 15 and the lower core 16, and the terminal electrodes 17a and 17b are formed on the side surfaces of the individual chips, whereby the coil component 10 according to the present embodiment is completed.

  As described above, in the coil component 10 according to the present embodiment, the magnetic body that covers the first and second spiral conductors 12 and 13 is a resin mold, and the dimensional processing accuracy is very high. The position accuracy of the coil is very high, and the size and thickness can be reduced. Since a magnetic metal material is used for the magnetic body and the direct current superimposition characteristic is better than that of ferrite, the formation of the magnetic gap can be omitted.

  FIG. 8 is a schematic side sectional view showing the configuration of the coil component 20 according to the second embodiment of the present invention.

  As shown in FIG. 8, the coil component 20 according to the second embodiment is that the lower core 23 is formed of a ferrite substrate. The material of the upper core 15 is a metal magnetic powder-containing resin as in the coil component 10 according to the first embodiment. Thus, in this embodiment, since the material of the upper core 15 and the lower core 23 is different, unlike the first embodiment, the boundary between them is clear. The upper core 15 is an E-type core and a lower core. Reference numerals 23 each constitute an I-type core. Since other configurations are substantially the same as those of the coil component 10 according to the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the manufacture of the coil component 20, first, the TFC substrate 21 shown in FIG. 4 is manufactured, the insulating resin layers 14 a and 14 b are respectively formed on both surfaces of the TFC substrate 21, and then on the ferrite substrate having the same size as the TFC substrate 21 This is mounted, and screen printing of the resin paste containing metal magnetic powder is performed on the ferrite substrate. Since the ferrite substrate is used, the UV tape 22 is unnecessary. After this screen printing, defoaming is performed, and the resin component is fully cured by heating at 160 ° C. for 1 hour, whereby the coil component 20 according to the present embodiment is completed.

  Thus, since the coil component 20 according to the present embodiment uses the metal magnetic powder-containing resin for the upper core 15, the same operational effects as those of the coil component 10 according to the first embodiment can be achieved. Further, since the ferrite substrate can be used as a support substrate at the time of forming the resin paste, the UV tape 22 does not have to be used and its manufacture is easy.

  FIG. 9 is a schematic plan view showing the configuration of the coil component 30 according to the third embodiment of the present invention.

  As shown in FIG. 9, the coil component 30 according to the third embodiment is characterized in that the upper core 15 and the lower core 16 are connected through connecting portions 15 d provided at the four corners outside the insulating substrate 11. That is, the connection part 15d by metal magnetic powder containing resin is formed only in the edge part of the width direction instead of the whole width direction of each side surface 18a-18d of a laminated body. The four corner connecting portions 15d are in contact with the edges of the corner portions of the insulating substrate 11, and have a quadrant shape in plan view. Since other configurations are substantially the same as those of the coil component 10 according to the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the material of the lower core 16 is not particularly limited as long as the material of the connecting portions 15d at the four corners is a resin containing metal magnetic powder. Therefore, the material of the lower core 16 may be a metal magnetic powder-containing resin or a ferrite substrate. In either case, since the upper core 15 and the lower core 16 are completely connected at the four corners of the insulating substrate 11, a closed magnetic circuit without a gap can be formed as in the first embodiment. Furthermore, in this embodiment, the formation area of the spiral conductors 12 and 13 can be expanded by forming closed magnetic paths at the four corners, and the loop size can be increased. Therefore, the resistance of the coil can be reduced, the inductance can be increased, and the size can be reduced.

  FIG. 10 is a schematic plan view showing the manufacturing process of the coil component 30.

  In manufacturing the coil component 30, the TFC substrate 21 is first manufactured. The manufacturing method of the TFC substrate 21 is the same as that of the coil component 10 according to the first embodiment. However, as shown in FIG. 10, it corresponds to the four corners of the insulating substrate after cutting, instead of the slit 11g in FIG. A substantially circular opening pattern 11k is formed at a position to be formed. The subsequent process is the same as the manufacturing process of the coil component 10, and the metal magnetic powder-containing resin is formed on both surfaces of the TFC substrate 21, and the metal magnetic powder-containing resin is embedded in the openings 11h and 11k (FIG. 5, (See FIG. 6). Thereafter, the TFC substrate 21 is cut along cutting lines Cx and Cy having the center of the opening 11k as an intersection, and then the terminal electrodes 17a and 17b are formed, whereby the coil component 30 is completed.

  FIG. 11 is a schematic plan view showing the configuration of a coil component according to the fourth embodiment of the present invention.

  As shown in FIG. 11, the coil component 40 according to the fourth embodiment is similar to the coil component 30 according to the third embodiment in that the upper core 15 and the lower core 16 are connected to the four corners outside the insulating substrate 11. However, unlike the coil component 30 according to the third embodiment, the connection portion is formed based on the individual openings 11m instead of the opening pattern 11k common to the four adjacent coil components. It is a feature.

  Further, the coil component 40 is provided with a plating conductor pattern 24 for short-circuiting the conductor patterns of adjacent chips during the mass production process. The conductor pattern 24 is provided so that a voltage can be simultaneously applied to all the conductor patterns during electroplating during mass production. For example, in the coil component 30 according to the third embodiment shown in FIGS. 9 and 10, since the spiral conductors of the chips adjacent in the left-right direction are electrically insulated and separated, the electroplating is performed collectively. I can't. However, when the individual openings 11k are formed at the four corners and the individual connecting portions based on the openings 11k are formed, the conductor pattern 24 extending in the left-right direction can be easily laid out. The conductive patterns of the chips can be collectively plated, and the manufacturing process can be made more efficient.

  In the state of a finished product in which individual chips are divided, one end of the plating conductor pattern 24 is electrically connected to the spiral conductor 12 (or the spiral conductor 13), and the other end extends to the edge of the insulating substrate 11 and opens. Become. The conductor pattern 24 is not necessarily formed at the edge of the insulating substrate 11, and may be formed at an arbitrary position. In that case, for example, the conductor pattern 24 can be formed on the coil component 30 according to the third embodiment.

  FIG. 12 is a schematic side sectional view showing the configuration of the coil component according to the fifth embodiment of the present invention.

  As shown in FIG. 12, the coil component 50 according to the fifth embodiment has a Ni-based ferrite-containing resin insulating coating 51 on the surface (exposed surface) of the metal magnetic powder-containing resin constituting the upper core 15 and the lower core 16. It is in a formed point. Although not particularly limited, the thickness of the insulating coating 51 is about 50 μm. The Ni-based ferrite-containing resin insulating film 51 functions not only as an insulating film but also as a part of a closed magnetic circuit together with the metal magnetic powder-containing resin.

  As described above, when the metal magnetic powder-containing resin is used as the magnetic core for forming the closed magnetic circuit, since the metal magnetic powder is a conductor, insulation between the terminal electrodes 17a and 17b becomes a problem. . However, according to the present embodiment, since the surface of the metal magnetic powder-containing resin is covered with insulation, sufficient insulation between the terminal electrodes 17a and 17b can be ensured. Furthermore, in the coil component 10 according to the first embodiment, the surfaces of the upper core 15 and the lower core 16 are insulated and coated by chemical conversion treatment, but this portion does not function as a closed magnetic circuit. However, according to the present embodiment, it is possible to make the insulating coating function as a part of the closed magnetic circuit while ensuring the insulation, and ultimately it is possible to improve the inductance characteristics.

  In the manufacture of the coil component 50, a metal magnetic powder-containing resin is formed on both surfaces of the TFC substrate 21 (see FIG. 6). Next, as shown in FIGS. 13A and 13B, a slit 52 is formed at the center in the width direction of the slit 11g in which the metal magnetic powder-containing resin is embedded. The blade width when forming the slit 52 is, for example, 100 μm.

  Next, as shown in FIG. 14, a Ni-based ferrite-containing resin paste is screen-printed on the entire surface of the substrate including the inside of the slit 52, and this is fully cured. Since the resin paste also enters the slit 52, the resin paste is formed not only on the upper and lower surfaces of the TFC substrate 21 on which the upper core 15 and the lower core 16 are formed, but also on the side surfaces.

  Next, the TFC substrate 21 is diced at the positions of the cutting lines Cx and Cy (see FIG. 7). The blade width at this time is, for example, 50 μm, and is narrower than the blade width at the time of slit formation, so that the Ni-based ferrite-containing resin can be partially left. Thereafter, by forming a pair of terminal electrodes 17a and 17b on the side surfaces of each chip, not only the upper and lower surfaces of the magnetic core but also the side surfaces of the coil component 50 covered with the insulating coating 51 of the Ni-based ferrite-containing resin can be obtained. Complete.

  FIG. 15 is a schematic cross-sectional side view showing the configuration of the coil component 60 according to the sixth embodiment of the present invention.

  As shown in FIG. 15, the coil component 60 according to the sixth embodiment is provided with two laminated insulating substrates 11A and 11B. The number of stacked layers is not limited to two and may be three or more. First and second spiral conductors 12 and 13 are formed on the upper and lower surfaces of the insulating substrates 11A and 11B, respectively, and the surfaces thereof are covered with insulating resin layers 14a and 14b, respectively. Since no resin is interposed, even if the insulating substrates 11A and 11B are overlapped, the upper and lower conductors do not contact and short-circuit. Since other configurations are substantially the same as those of the coil component 10 according to the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the above structure, a small amount of metal magnetic powder-containing resin unintended for manufacturing reasons may exist between the insulating substrates 11A and 11B. However, such a metal magnetic powder-containing resin does not affect the insulation characteristics. Therefore, it is sufficient that the metal magnetic powder-containing resin is not substantially interposed between the insulating substrates 11A and 11B.

  The first and second spiral conductors 12 and 13 formed on the upper and lower surfaces of the insulating substrate 11A constitute a single coil, and the first and second spiral conductors formed on the upper and lower surfaces of the insulating substrate 11B. 12 and 13 also constitute a single coil. The outer peripheral end 12b of the first spiral conductor 12 on one insulating substrate 11A and the outer peripheral end 12b of the first spiral conductor 12 on the insulating substrate 11B are electrically connected to each other via the first terminal electrode 17a. The outer peripheral end 13b of the second spiral conductor 13 on one insulating substrate 11A and the outer peripheral end 13b of the second spiral conductor 13 on the other insulating substrate 11B are connected to each other via the second terminal electrode 17b. By being electrically connected, the two coils are connected in parallel. In this way, when coils having the same structure are connected in parallel, the coil conductor cross-sectional area is doubled, so that the resistance of the coil can be halved and the DC resistance can be reduced. .

  FIGS. 16A and 16B are schematic views showing the configuration of the coil component 70 according to the seventh embodiment of the present invention. In FIG. 16, the laminated structure and spiral structure of the coil parts are omitted, and only the electrical configuration of the coil is shown in a simplified manner.

  As shown in FIGS. 16A and 16B, the coil component 70 according to the seventh embodiment includes two laminated insulating substrates 11A and 11B, and the first and second insulating substrates 11A and 11B formed on the insulating substrate 11A. A single coil (first coil) 71A composed of the second spiral conductors 12 and 13 and a single coil composed of the first and second spiral conductors 12 and 13 formed on the upper and lower surfaces of the other insulating substrate 11B. The coil (second coil) 71B is similar to the coil component 60 according to the sixth embodiment in that it is provided with a coil (second coil) 71B, but the coil 71A, 71B is connected in series instead of in parallel connection. Different from the part 70.

  The first coil 71A and the second coil 71B must be connected in series via an external terminal electrode. Therefore, a terminal electrode 17c for series connection is provided separately from the pair of terminal electrodes 17a and 17b. ing. As shown in FIG. 16A, the terminal electrode 17c has two other side surfaces 18c different from the two side surfaces 18a and 18b (see FIG. 2) on which the pair of terminal electrodes 17a and 17b are respectively formed. , 18d or may be formed on the same side surface 18a, 18b as shown in FIG. In the case of forming on the side surfaces 18a and 18b, the width of the pair of terminal electrodes 17a and 17b may be narrowed to form a four-terminal electrode structure, and the remaining one may be a dummy electrode 17d.

  As described above, when two insulating substrates 11A and 11B are used and a single coil 71A and 71B formed on each of the insulating substrates 11A and 11B are connected in series, one substrate is required. Since the number of turns of the coil to be reduced is reduced, the line width of the spiral conductor can be increased. Further, since the plating can be increased by increasing the conductor width, the cross-sectional area of the spiral conductor can be sufficiently increased, and the direct current resistance can be reduced.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the above embodiment, the inner peripheral end 12a of the first spiral conductor 12 and the inner peripheral end 13a of the second spiral conductor 13 are connected via the through-hole conductor 11i. For example, the inner peripheral ends may be connected to each other through a conductor pattern formed on the inner peripheral surface of the opening 11h of the printed board.

10, 20, 30, 40, 50, 60, 70 Coil parts 11, 11A, 11B Insulating substrate 11a Insulating substrate top surface 11b Insulating substrate back surface 11g Slit 11h Central opening 11i Through hole conductor (through hole)
11k Four corner openings (common)
11m Four corner openings (individual)
12 1st spiral conductor 12a 1st spiral conductor outer peripheral end 12b 1st spiral conductor inner peripheral end 13 2nd spiral conductor 13a 2nd spiral conductor outer peripheral end 13b 2nd spiral conductor inner peripheral end 14a, 14b Insulating resin layer 15 Upper core 15a Connecting portion (center)
15b Connecting part (outside)
15d connecting part (four corners)
15p Upper core resin paste 16 Lower core 16p Lower core resin paste 17a, 17b Terminal electrode 17c Series connection terminal electrode 17d Dummy electrode 18a First side surface 18b of multilayer body Second side surface 18c of multilayer body First layer surface 18c 3 side surface 18d Fourth side surface 19 of laminated body Insulating coating 21 TFC substrate 22 UV tape 23 Lower core (ferrite substrate)
24 Short-circuit pattern 51 Insulating coating 52 of Ni-based ferrite-containing resin Slit 71A Coil 71B on insulating substrate 11A Coils Cx, Cy on insulating substrate 11B Cutting line

Claims (4)

Forming a spiral conductor on at least one main surface of the insulating substrate;
Forming an upper core made of a metal magnetic powder-containing resin that covers the one main surface of the insulating substrate;
Forming a lower core made of the metal magnetic powder-containing resin covering the other main surface of the insulating substrate;
Dicing the insulating substrate together with the upper core and the lower core,
At least one of the step of forming the upper core and the step of forming the lower core is made of the metal magnetic powder-containing resin and is provided at each of a central portion and four corners of a rectangular region on the insulating substrate including the spiral conductor. Forming a connection part that is individually arranged to physically connect the upper core and the lower core;
The step of forming the connecting portion includes a step of forming an opening pattern penetrating the insulating substrate outside a central portion of the rectangular region and a position where the spiral conductor is formed, and the metal magnetic powder is contained inside the opening pattern. A method for manufacturing a coil component, comprising: embedding a resin; and dicing the metal magnetic powder-containing resin embedded in the opening pattern together with the insulating substrate.   The method for manufacturing a coil component according to claim 1, wherein the opening pattern is a substantially circular pattern formed at each of a central portion and four corners of the rectangular region.   3. The method of manufacturing a coil component according to claim 1, wherein an inner side surface of the connecting portion at the four corners contacting the side surface of the insulating substrate is a curved surface that swells toward the center of the insulating substrate.   The method for manufacturing a coil component according to any one of claims 1 to 3, wherein a planar shape of the connecting portion at the four corners is a substantially quarter circle.

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