JP2014197590A - Coil component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the thickening of the outermost peripheral turn of a spiral conductor, to suppress the height of a solder fillet, and to ensure required mounting strength by a small amount of solder.SOLUTION: A spiral conductor 11, a terminal electrode 13, and a dummy terminal electrode 15 are provided on an upper surface 10a of a substrate 10, and a spiral conductor 12, a terminal electrode 14, and a dummy terminal electrode 16 are provided on a lower surface 10b of the substrate 10. Extraction electrodes 26 and 27 penetrate a metal magnetic powder containing resin layer 17 to be respectively connected to an upper surface of the extraction electrode 13 and the upper surface of the dummy terminal electrode 15. Outer side surfaces of the terminal electrodes 13 and 14, the dummy terminal electrodes 15 and 16, and the extraction electrodes 26 and 27 are exposed without being covered by magnetic powder containing resin layers 17 and 18. Side surfaces 10c and 10d of the substrate 10 on the same plane surface as the outer side surfaces of the terminal electrodes 13 and 14 are exposed together with the outer side surfaces of the terminal electrodes 13 and 14 without being covered by the metal magnetic powder containing resin layers 17 and 18.

Description

  The present invention relates to a coil component, and more particularly to a surface mount type coil component used for a power supply.

  A variety of internal power sources are used in portable wireless terminals such as smartphones, and advanced power saving is achieved. In order to generate such an internal power supply, a small and high-performance power supply coil (power inductor) is required, and in recent years, the necessity thereof is particularly increased due to the spread of smartphones.

  A planar coil structure that can be reduced in size and thickness is employed for the surface mount type power supply coil (see, for example, Patent Document 1). In the planar coil structure, a spiral planar coil conductor is formed on a single-layer or multilayer substrate. The power supply coil is required to have a low DC resistance of the coil conductor, and the DC resistance is reduced by forming the coil conductor thick by electrolytic plating. In particular, it is possible to sufficiently increase the thickness of the coil conductor by increasing the current flowing during the electrolytic plating and growing the plating at a high speed.

Japanese Patent No. 4873049

  However, when the coil conductor is formed thick by electrolytic plating, the outermost peripheral turn of the spiral coil conductor grows abnormally in the lateral direction and the line width becomes extremely thick, so that a desired pattern cannot be formed. is there. In order to meet the demands of high-density mounting, it is necessary to reduce the area occupied by the coil components as much as possible while securing the desired mounting strength. There is a need to reduce costs.

  Accordingly, an object of the present invention is to provide a coil component capable of preventing the outermost shape of the spiral conductor from being greatly deformed and ensuring a desired mounting strength with a small amount of solder during surface mounting. is there.

  In order to solve the above problems, a surface mount type coil component according to the present invention includes a substrate, first and second spiral conductors formed on one and other main surfaces of the substrate, and the one main surface, respectively. A first terminal electrode connected to the outer peripheral end of the first spiral conductor and a second terminal formed on the other main surface and connected to the outer peripheral end of the second spiral conductor An electrode, a first through-hole conductor that penetrates through the substrate and connects inner peripheral ends of the first and second spiral conductors, and is formed on the one main surface, and the second terminal electrode, A first dummy terminal electrode provided at a position overlapping in plan view, and a second dummy terminal electrode formed on the other main surface and provided at a position overlapping with the first terminal electrode in plan view And the first dummy end penetrating the substrate A second through-hole conductor connecting the electrode and the second terminal electrode; and the first spiral conductor, the first terminal electrode, and the first dummy terminal electrode formed on the one main surface. A first metal magnetic powder-containing resin layer covering the first metal magnetic layer, and a second metal magnetic layer formed on the other main surface and covering the second spiral conductor, the second terminal electrode, and the second dummy terminal electrode. A powder-containing resin layer, a first lead electrode penetrating the first metal magnetic powder-containing resin layer and connected to the upper surface of the first terminal electrode, and the first metal magnetic powder-containing resin layer. A second lead electrode penetrating through and connected to the upper surface of the first dummy terminal electrode, the first and second terminal electrodes, the first and second dummy terminal electrodes, and the first And each outer side surface of the second extraction electrode includes the first and second magnetic powders. The side surface of the substrate that is exposed without being covered with resin and is flush with the outer side surface of the first and second terminal electrodes is formed on the first and second metal magnetic powder-containing resin layers. The first and second terminal electrodes are exposed together with the outer side surfaces without being covered.

  According to the present invention, since the first and second dummy terminal electrodes are provided together with the first and second spiral conductors, the outermost turns of the first and second spiral conductors are prevented from being thickened, respectively. be able to. Further, since the outer side surface of the first terminal electrode and the outer side surface of the first dummy terminal electrode are exposed on the side surface of the coil component, a solder fillet can be formed at the time of surface mounting, and the mounting strength at the time of solder connection Can be increased. Furthermore, since the exposed surface of the second substrate serves as a stopper surface that suppresses the formation of the solder fillet, the exposed surface of the second dummy terminal electrode exposed together with the first terminal electrode and the first dummy terminal electrode are exposed. It is possible to prevent the solder fillet from being formed up to the second terminal electrode. Therefore, the solder fillet can be formed with as little solder as possible, and the material cost can be reduced. Furthermore, when the upper part of the coil component is covered with a shield cover, the solder melted or remelted during the reflow process crawls upward along the side electrodes and adheres to the shield cover, resulting in poor electrical connection. Occurrence can be prevented.

  In the present invention, the substrate has first and second side surfaces parallel to each other, and third and fourth side surfaces orthogonal to the first and second side surfaces, and the first side of the substrate. The side surface is flush with the outer side surface of the first terminal electrode and the outer side surface of the second dummy terminal electrode, and the second side surface of the substrate is the outer side surface of the second terminal electrode. The first dummy terminal electrode is preferably flush with the outer side surface of the first dummy terminal electrode. According to this configuration, a solder fillet can be formed on each of the pair of side electrodes during surface mounting, and the mounting strength during solder connection can be increased. In addition, the solder fillet can be formed with as little solder as possible, and the material cost can be reduced.

  The coil component according to the present invention further includes a through-hole magnetic body that penetrates through a corner portion of the substrate and connects the first magnetic powder-containing resin layer and the second magnetic powder-containing resin layer. The first and second side surfaces are preferably provided in a region excluding the formation region of the through-hole magnetic body. According to this configuration, a solder fillet can be formed with a smaller amount of solder, and a coil component with high inductance can be provided.

  The coil component according to the present invention further includes first and second external electrodes formed on a main surface of the first metal magnetic powder-containing resin layer and connected to the first and second extraction electrodes, respectively. The first external electrode constitutes a first L-shaped electrode together with the first extraction electrode, the first terminal electrode, and the first dummy terminal electrode, and the second external electrode, It is preferable that a second L-shaped electrode is formed together with the second extraction electrode, the second terminal electrode, and the second dummy terminal electrode. According to this configuration, it is possible to further increase the mounting strength during solder connection by increasing the electrode area.

  According to the present invention, a coil capable of preventing the outermost shape of the spiral conductor from being greatly deformed, suppressing the height of the solder fillet, and ensuring a desired mounting strength with a small amount of solder during surface mounting. Parts can be provided.

FIG. 1 is a schematic exploded perspective view showing the structure of a coil component according to the first embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the coil component 1. FIG. 3 is a schematic side cross-sectional view showing the surface mounting state of the coil component 1. FIG. 4 is a schematic view for explaining the mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 5 is a schematic view for explaining a mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 6 is a schematic diagram for explaining a mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 7 is a schematic diagram for explaining a mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 8 is a schematic diagram for explaining a mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 9 is a schematic diagram for explaining a mass production process of the coil component 1 and is a plan view of the substrate 10 before cutting as viewed from the upper surface 10a side. FIG. 10 is a schematic diagram for explaining the function of the dummy terminal electrode. FIG. 11 is a schematic exploded perspective view showing the structure of the coil component 2 according to the second embodiment of the present invention.

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

  FIG. 1 is a schematic perspective view showing the external shape of the coil component 1 according to the first embodiment of the present invention.

  As shown in FIG. 1, the coil component 1 according to the present embodiment is a surface-mount type chip component, and a thin film coil layer 3 including a planar coil conductor and first and second thin film coil layers 3 are provided to overlap each other. The first and second metal magnetic powder-containing resin layers 17 and 18 are included. The outer shape of the coil component 1 is a rectangular parallelepiped, and has an upper surface 1a, a bottom surface 1b, and four side surfaces 1c to 1f.

  A pair of external electrodes 28 and 29 are provided on the upper surface 1a of the coil component 1 (the main surface of the first metal magnetic powder-containing resin layer 17), and two opposing side surfaces 1c and 1d of the coil component 1 are provided. Are provided with a pair of side electrodes 30, 31 respectively. The combination of the external electrode 28 and the side electrode 30 constitutes one L-shaped electrode, and the combination of the external electrode 29 and the side electrode 31 constitutes the other L-shaped electrode. According to this L-shaped electrode, a solder fillet can be formed when the coil component 1 is mounted. In mounting, the coil component 1 is used with the upper surface 1a facing downward so that the external electrodes 28 and 29 face the mounting surface. The thin film coil layer 3 includes a substrate 10 for supporting a planar coil conductor, and each side surface of the substrate 10 is exposed from each side surface 1 c to 1 f of the coil component 1. In particular, the side surface of the substrate 10 exposed from the side surfaces 1c and 1d of the coil component 1 is located in the region where the side surface electrodes 30 and 31 are formed. For this reason, the side electrodes 30 and 31 are divided in the vertical direction.

  FIG. 2 is a schematic exploded perspective view of the coil component 1.

  As shown in FIG. 2, the coil component 1 includes a substrate 10, a first spiral conductor 11, a first terminal electrode 13, and a first dummy terminal formed on the upper surface 10 a (one main surface) of the substrate 10. The electrode 15, the second spiral conductor 12, the second terminal electrode 14, the second dummy terminal electrode 16 formed on the lower surface 10 b (the other main surface) of the substrate 10, and the upper surface 10 a and the lower surface 10 b of the substrate 10. Are provided with first and second metal magnetic powder-containing resin layers 17 and 18, respectively.

  The external shape of the substrate 10 in the planar direction is rectangular, and has two side surfaces 10c and 10d parallel to the X direction in the drawing, and two side surfaces 10e and 10f parallel to the Y direction. A first through hole 10g is provided in the central portion of the substrate 10, and a quadrant-shaped second through hole 10h (notched portion) having chamfered corners is provided at four corners of the substrate 10. It has been. Therefore, the exact planar shape of the substrate 10 is not rectangular. Further, the corner of the substrate 10 means a corner of a complete rectangular substrate that is not chamfered.

  The first spiral conductor 11 is formed on the upper surface 10 a of the substrate 10, and the second spiral conductor 12 is formed on the lower surface 10 b of the substrate 10. The positions in the planar direction of the inner peripheral ends of the first and second spiral conductors 11 coincide with each other and are connected to each other via a first through-hole conductor 19 penetrating the substrate 10. On the other hand, the outer peripheral end of the first spiral conductor 11 and the outer peripheral end of the second spiral conductor 12 are positioned on opposite sides of the main parts of the first and second spiral conductors 11 and 12. That is, the position of the outer peripheral end of the first spiral conductor 11 is near the side surface 10 c of the substrate 10, and the position of the outer peripheral end of the second spiral conductor 12 is near the side surface 10 d of the substrate 10.

  The first spiral conductor 11 and the second spiral conductor 12 are wound in opposite directions. The first spiral conductor 11 viewed from the upper surface 10 a side of the substrate 10 is wound counterclockwise from the inner peripheral end toward the outer peripheral end, whereas the second spiral conductor 11 viewed from the upper surface 10 a side of the substrate 10. The spiral conductor 12 is wound clockwise from the inner peripheral end toward the outer peripheral end. According to this winding structure, when a current flows from one of the outer peripheral ends of the first and second spiral conductors 11 and 12 to the other, the currents flowing through the first and second spiral conductors 11 and 12 are mutually Strengthen each other by generating a magnetic field in the same direction. Therefore, the first and second spiral conductors 11 and 12 can function as a single inductor.

  The first terminal electrode 13 is formed on the upper surface 10 a of the substrate 10 and is connected to the outer peripheral end of the first spiral conductor 11. The first terminal electrode 13 is located outside the outermost peripheral turn of the first spiral conductor 11 and is provided in contact with the common side of the first side surface 10 c and the upper surface 10 a of the substrate 10. Therefore, the outer side surface of the first terminal electrode 13 is flush with the side surface 10 c of the substrate 10.

  The second terminal electrode 14 is formed on the lower surface 10 b of the substrate 10 and is connected to the outer peripheral end of the second spiral conductor 12. The second terminal electrode 14 is located outside the outermost turn of the second spiral conductor 12 and is provided in contact with the common side of the second side surface 10 d and the lower surface 10 b of the substrate 10. Therefore, the outer side surface of the second terminal electrode 14 is flush with the side surface 10 d of the substrate 10.

  The first dummy terminal electrode 15 is formed on the upper surface 10a of the substrate 10 and is not connected to the first spiral conductor 11 in the same plane, but the second through-hole conductor 20 penetrating the substrate 10 is provided. And is connected to the second terminal electrode 14. The first dummy terminal electrode 15 is positioned immediately above the second terminal electrode 14 so as to overlap the second terminal electrode 14 in plan view, and has a planar shape that is slightly smaller than the second terminal electrode 14. The first dummy terminal electrode 15 is located outside the outermost peripheral turn of the first spiral conductor 11 and is provided in contact with the common side of the second side surface 10 d and the upper surface 10 a of the substrate 10. Therefore, the outer side surface of the first dummy terminal electrode 15 is flush with the second side surface 10 d of the substrate 10 and the second terminal electrode 14.

  The second dummy terminal electrode 16 is formed on the lower surface 10b of the substrate 10 and is not connected to the second spiral conductor 12 in the same plane, but the third through-hole conductor 21 penetrating the substrate 10 is provided. And is connected to the first terminal electrode 13. The second dummy terminal electrode 16 is positioned immediately below the first terminal electrode 13 so as to overlap the first terminal electrode 13 in plan view, and has a planar shape that is slightly smaller than the first terminal electrode 13. The second dummy terminal electrode 16 is located outside the outermost peripheral turn of the second spiral conductor 12 and is provided in contact with the common side of the first side surface 10 c and the lower surface 10 b of the substrate 10. Therefore, the outer side surface of the second dummy terminal electrode 16 is flush with the first side surface 10 c of the substrate 10 and the outer side surface of the first terminal electrode 13.

  Note that the outer side surface of the terminal electrode (or dummy terminal electrode) and the side surface of the substrate 10 are the same plane as long as they can be viewed as the side surface of the coil component. It is not required to be coplanar. Therefore, even if the outer side surface of the terminal electrode or dummy terminal electrode is slightly higher (for example, about several μm to several tens μm) than the corresponding side surface of the substrate 10 by barrel plating described later, for example, The planes are coplanar.

  The inner side surface of the first dummy terminal electrode 15 facing the outermost turn of the first spiral conductor 11 is curved in accordance with the shape of the outermost turn of the first spiral conductor 11. The side surface of the second dummy terminal electrode 16 facing the second spiral conductor 12 is also curved in accordance with the shape of the outermost peripheral turn of the second spiral conductor 12. When the inner side surfaces of the first and second dummy terminal electrodes 15 and 16 have such a curved shape, excessive lateral lateral turns of first and second spiral conductors 11 and 12 described later are excessive. Plating growth can be suppressed, and a highly accurate pattern can be formed. The space width between the spiral conductor and the dummy terminal electrode is preferably set substantially equal to the pitch width of the spiral conductor. In this case, the outermost line width can be made equal to that of the inner line, so that a more accurate pattern can be formed.

  The first and second spiral conductors 11 and 12, the first and second terminal electrodes 13 and 14, and the first and second dummy terminal electrodes 15 and 16 are all formed with an underlying layer by electroless plating or the like. Thereafter, it is formed through two electrolytic plating processes at the same time. It is preferable that the material of the underlayer and the plating material used in the two electrolytic plating processes are both Cu. The second electrolytic plating process is a process for rapidly forming a thicker plating layer by supplying a larger current than the first. In the second plating step, the outermost and innermost turns of the spiral conductor may grow greatly in the lateral direction. However, since the dummy terminal electrodes 15 and 16 are provided in the present embodiment, the outermost periphery of the spiral conductors 11 and 12 does not become extremely thick, and a desired line width can be maintained.

  A first extraction electrode 26 is formed on the upper surface of the terminal electrode 13, and a second extraction electrode 27 is formed on the upper surface of the dummy terminal electrode 15. The first and second lead electrodes 26 and 27 form a resist pattern that covers the entire surface of the substrate 10 except for the upper surface of the terminal electrode 13 and the upper surface of the dummy terminal electrode 15, and expose the terminal electrode 13 and the dummy terminal electrode 15. It is formed by further plating growth of the surface.

  The planar shape of the first lead electrode 26 is preferably the same as or slightly smaller than the shape of the first terminal electrode 13. The planar shape of the second extraction electrode 27 is preferably the same as or slightly smaller than the shape of the first dummy terminal electrode 15. According to this configuration, the thick extraction electrodes 26 and 27 can be reliably formed.

  The first spiral conductor 11 provided on the upper surface 10 a side of the substrate 10 is covered with a thin insulating resin layer 22. The second spiral conductor 12, the second terminal electrode 14, and the second dummy terminal electrode 16 provided on the lower surface 10 b of the substrate 10 are covered with a thin insulating resin layer 23. The insulating resin layers 22 and 23 are provided to prevent electrical conduction between the conductor pattern on the substrate 10 and the metal magnetic powder-containing resin layers 17 and 18.

  Metal magnetic powder-containing resin layers 17 and 18 are further provided on the upper surface 10a and the lower surface 10b of the substrate 10 from above the insulating resin layers 22 and 23, respectively.

  The metal magnetic powder-containing resin layers 17 and 18 are made of a magnetic material (metal magnetic powder-containing resin) made by mixing metal magnetic powder into a resin as an insulating binder. As the metal magnetic powder, a permalloy material is preferably used. Specifically, for example, a Pb—Ni—Co alloy having an average particle diameter of 20 to 50 μm and carbonyl iron having an average particle diameter of 3 to 10 μm are in a predetermined ratio, for example, 70:30 to 80:20. It is preferable to use a metal magnetic powder containing a weight ratio, preferably 75:25. Further, the metal magnetic powder may contain a Fe—Si—Cr alloy instead of the Pb—Ni—Co alloy. In this case, the content of the Fe—Si—Cr alloy (weight ratio to carbonyl iron) may be the same as that of the Pb—Ni—Co alloy.

  On the other hand, it is preferable to use a liquid or powdery epoxy resin as the resin. The content of the metal magnetic powder in the metal powder-containing resin layer is preferably 90 to 97% by weight. The smaller the content of the metal magnetic powder relative to the resin, the smaller the saturation magnetic flux density. Conversely, the greater the content of the metal magnetic powder, the greater the saturation magnetic flux density.

  As described above, the first through hole 10g is provided at the center of the substrate 10, and the semicircular second through holes 10h are provided at the corners of the four corners of the substrate 10, respectively. . The metal magnetic powder-containing resin constituting the metal magnetic powder-containing resin layers 17 and 18 is also embedded in the through holes 10g and 10h, and the embedded metal magnetic powder-containing resin is, as shown in FIG. The magnetic bodies 24 and 25 are respectively configured. Although not essential in the present invention, the through-hole magnetic bodies 24 and 25 are for forming a complete closed magnetic circuit in the coil component 1.

  First and second external electrodes 28 and 29 are formed on the main surface of the metal magnetic powder-containing resin layer 17. FIG. 2 shows a state in which the mounting surface of the coil component 1 faces upward. The external electrodes 28 and 29 are connected to the terminal electrodes 13 and 14 through the extraction electrodes 26 and 27 that penetrate the metal magnetic powder-containing resin layer 17, respectively. The external electrodes 28 and 29 are soldered to lands on the circuit board.

  The external electrodes 28 and 29 have a rectangular pattern and have a larger area than the upper surfaces of the extraction electrodes 26 and 27 exposed from the main surface of the metal magnetic powder-containing resin layer 17. In order to increase the inductance of the coil, the coil formation region must be made as large as possible. In order to design the coil forming area as large as possible within a predetermined dimension, the terminal electrodes 13 and 14 and the dummy terminal electrodes 15 and 16 arranged outside the coil are preferably as small as possible. However, if the areas of the terminal electrodes 13 and 14 and the dummy terminal electrodes 15 and 16 are reduced, the area of the upper surface of the extraction electrodes 26 and 27 formed thereon is also reduced, and the upper surfaces of the extraction electrodes 26 and 27 are left as they are. Even if it is used as an external electrode, the electrode area is too small to maintain the mounting strength. Therefore, in the present embodiment, the external electrodes 28 and 29 having a larger area than the upper surfaces of the extraction electrodes 26 and 27 are provided to ensure a desired mounting strength.

  Although not shown, a thin insulating layer is formed on the surfaces of the metal magnetic powder-containing resin layers 17 and 18. This insulating layer is formed by treating the surfaces of the metal magnetic powder-containing resin layers 17 and 18 with phosphate. By providing this insulating layer, electrical conduction between the external electrodes 28 and 29 and the metal magnetic powder-containing resin layers 17 and 18 can be prevented.

  In the present embodiment, the first and second external electrodes 28 and 29 are formed on the main surface of the first metal magnetic powder-containing resin layer 17 (the upper surface 1a of the coil component 1). Further, on the side surface of the coil component 1, the outer side surfaces of the first and second terminal electrodes 13 and 14, the outer side surfaces of the first and second dummy terminal electrodes 15 and 16, and the first and second extraction electrodes 26, The outer side surface of 27 is exposed. The first external electrode 28 is combined with the first terminal electrode 13, the second dummy terminal electrode 16, and the first extraction electrode 26 to form an L-shaped electrode, and the second external electrode 29 is The second terminal electrode 14, the first dummy terminal electrode 15, and the second extraction electrode 27 are combined to form an L-shaped electrode. According to the L-shaped electrode, a solder fillet can be formed at the time of surface mounting, and the mounting strength can be increased. Moreover, the solder connection state can be visually confirmed, and reliable mounting is possible.

  FIG. 3 is a schematic side cross-sectional view showing the surface mounting state of the coil component 1.

  As shown in FIG. 3, in the present embodiment, the side surface 10 c of the substrate 10 sandwiched between the first terminal electrode 13 and the second dummy terminal electrode 16 is the first terminal electrode 13 and the second terminal electrode 13. The dummy terminal electrode 16 is exposed to the side surface 1c of the coil component 1 together with the outer side surface, and the side surface 10d of the substrate 10 sandwiched between the second terminal electrode 14 and the first dummy terminal electrode 15 is the second side. Since the terminal electrode 14 and the first dummy terminal electrode 15 are exposed to the side surface 1d of the coil component 1 together with the outer side surface of the first dummy terminal electrode 15, the height of the solder fillet F can be suppressed during reflow mounting. As shown in the figure, since the terminal electrode and the dummy terminal electrode are provided with the substrate sandwiched therebetween, if one of them is exposed, the other is also exposed, and the height of the side electrode is inevitably increased. For example, when the side electrode is exposed when the upper part of the coil component 1 is covered with a metal shield cover, contact between the solder fillet F and the shield cover becomes a problem. However, when the side surface of the substrate 10 is exposed, it is possible to prevent the solder from climbing upward along the side electrode and adhering to the shield cover.

  Next, the manufacturing method of the coil component 1 is demonstrated.

  4 to 9 are schematic views for explaining the mass production process of the coil component 1, and are plan views of the substrate 10 before cutting as viewed from the upper surface 10a side. In addition, the broken line shown in each figure has shown the cutting line in a dicing process. Each rectangular area (hereinafter simply referred to as “rectangular area”) surrounded by the cutting line corresponds to each coil component 1. Hereinafter, description will be made by paying attention to the central rectangular region surrounded by the cutting lines A1, A2, A4, and A5.

  First, as shown in FIG. 4, the substrate 10 is provided with through holes 10g, 10s for forming a magnetic path and through holes 10i, 10j, 10k for embedding conductors. One through hole 10g and one through hole 10i, 10j, 10k are provided for each rectangular area. Note that the pattern shape of the upper, lower, left and right rectangular regions is two-fold symmetric with respect to the pattern shape of the central rectangular region, and therefore the through hole formation position is also different.

  Each through hole 10s has a circular pattern, and is provided at each intersection of cutting lines A1, A2 extending in the X direction and cutting lines A3, A4, A5, A6 extending in the Y direction. Therefore, one through hole 10s is common to four coil components, and four through holes 10s are involved in one rectangular region. If the board | substrate 10 is cut | disconnected in the position of each cutting line, the through-hole 10h (refer FIG. 2) of quarter circle shape will be obtained in the corner | angular part of each board | substrate.

  Next, as shown in FIG. 5, the first spiral conductor 11, the first terminal electrode 13, and the first dummy terminal electrode 15 are formed for each rectangular region on the upper surface 10 a of the substrate 10. These conductor patterns can be formed by electrolytic plating described later. Here, the inner peripheral end of the first spiral conductor 11, the first terminal electrode 13 and the first dummy terminal electrode 15 cover the through holes 10i, 10j and 10k, respectively, and the electrode material is embedded in each through hole. As a result, first to third through-hole conductors 19, 20, and 21 are formed.

  The first terminal electrode 13 is formed as an integrated electrode in which the first terminal electrodes 13 in two rectangular regions adjacent to each other across the cutting line A1 are integrated, and one dummy terminal electrode 15 is also formed. The first dummy terminal electrodes 15 in two rectangular regions adjacent to each other across the cutting line A2 are formed as an integrated electrode.

  Although not shown, the second spiral conductor 12, the second terminal electrode 14, and the second dummy terminal electrode 16 are similarly formed for each rectangular region on the lower surface 10b of the substrate 10. Here, the inner peripheral end of the second spiral conductor 12, the second terminal electrode 14, and the second dummy terminal electrode 16 cover the through holes 10i, 10j, and 10k, respectively. Thereby, the inner peripheral end of the second spiral conductor 12, the second terminal electrode 14, and the second dummy terminal electrode 16 are connected to the first through third through-hole conductors 19, 20, and 21. The spiral conductor 11 is connected to the inner peripheral end, the first terminal electrode 13 and the first dummy terminal electrode 15, respectively.

  Further, the second terminal electrode 14 is formed as a collective electrode in which the second terminal electrodes 14 in two rectangular regions adjacent to each other are integrated, and the first dummy terminal electrode 16 is also adjacent to each other in two rectangular shapes. The first dummy terminal electrodes 16 in the region are formed as an integrated electrode.

  A specific method of forming the conductor patterns formed on the upper surface 10a and the lower surface 10b of the substrate 10 is as follows.

  First, a Cu underlayer is formed on the entire upper surface 10a and lower surface 10b of the substrate 10. The underlayer can be formed by electroless plating or sputtering. Next, a photoresist layer is formed on the surface of the underlayer. The photoresist layer can be formed, for example, by attaching a sheet resist. This underlayer is also formed on the inner wall surface of each through hole. Subsequently, an opening pattern (negative pattern) of the first and second spiral conductors 11 and 12, the first and second terminal electrodes 13 and 14, and the first and second dummy terminal electrodes 15 and 16 in the photoresist layer. Is formed by photolithography.

  Next, the first electrolytic plating step (first plating step) is performed. In this electrolytic plating process, the substrate 10 is immersed in a plating solution while flowing a plating current through the underlayer, and a portion of the underlayer exposed from the opening pattern is plated and grown. Here, since the underlayer is a planar conductor that is not patterned, there is no problem regarding the direction in which the plating current flows. Thereafter, the photoresist layer is removed, and an extra base layer is removed by etching. Through the above steps, the first and second spiral conductors 11 and 12, the first and second terminal electrodes 13 and 14, and the first and second dummy terminal electrodes 15 and 16, which are each composed of a base layer and a plating layer, respectively. The basic pattern is completed.

  Next, a second electrolytic plating step (second plating step) is performed. In this electrolytic plating process, the substrate 10 is immersed in a plating solution while a very large plating current is applied to the basic pattern to form a thicker conductor pattern. In addition, by connecting the conductor pattern in each rectangular region not only in the y direction but also in the x direction so that the plating current flows in both the x direction and the y direction, the metal ions can be uniformly electrodeposited. And a plating layer having a uniform film thickness can be formed.

  The film thickness of each conductor pattern can be greatly increased by the second electrolytic plating process. The reason why the film thickness of the conductor pattern is increased in this way is that the coil component 1 according to the present embodiment is a power supply coil and a very small DC resistance is required.

  FIG. 10 is a schematic diagram for explaining the function of the dummy terminal electrode.

  As shown in FIG. 10 (a), when the second electroplating step is performed, the plating layer of the outermost peripheral turn To of the spiral conductor having no adjacent turn is likely to grow larger in the lateral direction than the intermediate turn Tm, and the line There is a tendency for the width to become extremely thick. However, in this embodiment, as shown in FIG. 10B, a dummy terminal electrode Dm is provided outside the outer peripheral turn, and a gap having a constant width is provided between the outermost peripheral turn To of the spiral conductor and the dummy terminal electrode Dm. Therefore, it is possible to suppress the plating growth in the lateral direction of the outermost peripheral turn To of the spiral conductor. Accordingly, it is possible to prevent the line width of the outermost turn of the spiral conductor from becoming extremely thick.

  Next, as shown in FIG. 6, the upper surfaces of the first terminal electrode 13 and the first dummy terminal electrode 15 are selectively plated to form first and second lead electrodes 26 and 27, respectively. To do. The first and second extraction electrodes 26 and 27 are formed by integrating the first extraction electrodes 26 or the second extraction electrodes 27 in two rectangular regions adjacent to each other across the cutting line A1 or A2. It is formed as a collecting electrode. In the formation of the first and second extraction electrodes 26 and 27, a photoresist layer is formed on the entire surface of the substrate, and negative patterns (opening patterns) of the first and second extraction electrodes 26 and 27 are formed on the photoresist layer. It is formed by photolithography.

  Next, a third electrolytic plating step (third plating step) is performed. Also in this electrolytic plating process, the substrate 10 is immersed in the plating solution while flowing a very large plating current, and the thicker extraction electrodes 26 and 27 are formed. Thereafter, the photoresist layer is removed. Through the above steps, the first and second extraction electrodes 26 and 27 made of a plating layer are formed.

  Thereafter, as shown in FIG. 7, an insulating resin is formed on both surfaces of the substrate 10, and each conductor is covered with insulating resin layers 22 and 23. At this time, the extraction electrode is also covered with the insulating resin layer. Further, the side walls of the through holes 10g and 10h are also covered with the insulating resin, but it is necessary to prevent the entire areas of the through holes 10g and 10h from being filled with the insulating resin.

  Next, as shown in FIG. 8, metal magnetic powder-containing resin layers 17 and 18 are formed on both surfaces of the substrate 10, respectively. Specifically, first, a UV tape (not shown) for suppressing the warpage of the substrate 10 is attached to the lower surface 10b of the substrate 10, and a metal magnetic powder-containing resin paste is screen-printed on the upper surface 10a, and then the paste is heated. To cure. A heat release tape may be used instead of the UV tape. Subsequently, the UV tape is peeled off, a metal magnetic powder-containing resin paste is screen-printed on the lower surface 10b of the substrate 10, and the paste is heated and cured. Thereafter, the surfaces of the metal magnetic powder-containing resin layers 17 and 18 are polished to adjust their thickness. At this time, the leading ends of the extraction electrodes 26 and 27 are exposed from the main surface of the metal magnetic powder-containing resin layer 17. By the above processing, the metal magnetic powder-containing resin layers 17 and 18 are completed. The metal magnetic powder-containing resin paste is also embedded in the through holes 10g and 10h, thereby forming the through hole magnetic bodies 24 and 25 shown in FIGS.

  Next, as shown in FIG. 9, first and second external electrodes 28 and 29 are formed on the surface of the metal magnetic powder-containing resin layer 17. The first and second external electrodes 28 and 29 are formed as a collective electrode in which external electrodes in two rectangular regions adjacent to each other across the cutting lines A1 and A2 are integrated.

  In forming the first and second external electrodes 28 and 29, first, the insulating resin layer 23 is formed on the surfaces of the metal magnetic powder-containing resin layers 17 and 18. The insulating resin layer 23 is formed by subjecting the surfaces of the metal magnetic powder-containing resin layers 17 and 18 to chemical conversion treatment with phosphate. Thereafter, the first and second external electrodes 28 and 29 are formed so as to cover the exposed positions of the upper ends of the first and second extraction electrodes 26 and 27 and to be electrically connected to the extraction electrodes 26 and 27. . The external electrode is preferably formed by sputtering, but may be formed by screen printing.

  Thereafter, the substrate 10 is diced along the cutting lines A1 to A4. Thereby, each coil component 1 is obtained for every rectangular area. As shown in FIGS. 1 to 3, the outer side surfaces of the terminal electrodes 13 and 14, the dummy terminal electrodes 15 and 16, and the extraction electrodes 26 and 27 are exposed on the side surfaces of the individual coil components by this dicing. Furthermore, the side surfaces 10c and 10d of the substrate 10 are also exposed together with these electrode surfaces.

  Finally, the first and second terminal electrodes 13 and 14, the first and second dummy terminal electrodes 15 and 16, and the first and second external electrodes 28 and 29 are finished to smooth the electrode surfaces. Plating treatment (barrel plating) is performed. Thus, the coil component 1 according to the present embodiment is completed.

  As described above, in the coil component manufacturing method according to the present embodiment, the first and second dummy terminal electrodes 15 and 16 are formed outside the outermost peripheral turns of the spiral conductors 11 and 12, respectively. Since the first and second spiral conductors 11 and 12 are formed thick by performing the electric field plating step, plating growth in the lateral direction of the plating layer of the outermost turn can be suppressed. Therefore, it is possible to prevent the outermost line width of the spiral conductors 11 and 12 from becoming extremely thick.

  FIG. 11 is a schematic exploded perspective view showing the configuration of the coil component 2 according to the second embodiment of the present invention.

  As shown in FIG. 11, the feature of the coil component 2 according to the present embodiment is that the through-hole magnetic body 25 provided at the corner of the substrate 10 is omitted. Thereby, the through hole 10h is not formed in the substrate 10, and the side surfaces 10c and 10d of the substrate 10 are equal to the maximum width of the substrate. In accordance with the shape of the substrate 10, the first and second terminal electrodes 13, 14 and the first and second dummy terminal electrodes 15, 16 also have the same width as the side surfaces 10c, 10d of the substrate. According to the present embodiment, like the coil component 1 according to the first embodiment, the side surfaces 10c and 10d of the substrate 10 sandwiched between the terminal electrodes 13 and 14 and the dummy terminal electrodes 15 and 16 are the terminal electrodes. And since it is exposed together with the dummy terminal electrode, the height of the solder fillet can be suppressed. In addition, the thickness of the outermost turns of the first and second spiral conductors can be suppressed in a wider range. Further, in the mass production process, it is possible to increase the number of plating current paths by connecting adjacent terminal electrodes in the lateral direction, and to reduce in-plane variations in the thickness of the plating layer.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention, and it goes without saying that these are also included in the present invention. .

  For example, in the above-described embodiment, the third through-hole conductor 21 that connects the first terminal electrode 13 and the second dummy terminal electrode 16 is provided, but the third through-hole conductor 21 is omitted. Is also possible. Moreover, the formation position, shape, number of houses, etc. of the through-hole magnetic body 25 are arbitrary, and are not limited to the first and second embodiments.

  Moreover, in the said embodiment, although the coil component formed by forming the 1st and 2nd spiral conductors on both surfaces of a single board | substrate was mentioned as an example, this invention is a coil formed by multilayering such a board | substrate. It may be a part.

DESCRIPTION OF SYMBOLS 1 Coil component 1a Coil component upper surface 1b Coil component bottom surface 1c, 1d, 1e, 1f Coil component side surface 2 Coil component 3 Thin film coil layer 10 Substrate 10a Substrate upper surface 10b Substrate lower surface 10c Substrate first side surface 10d Substrate Second side surface 10e Third side surface 10f of substrate Fourth side surface 10g, 10h, 10i, 10j, 10k, 10s of substrate Through hole 11 First spiral conductor 12 Second spiral conductor 13 First terminal electrode 14 2nd terminal electrode 15 1st dummy terminal electrode 16 2nd dummy terminal electrode 17 1st metal magnetic powder containing resin layer 18 2nd metal magnetic powder containing resin layer 19 1st through-hole conductor 20 2nd Through-hole conductor 21 Third through-hole conductor 22 First insulating resin layer 23 Second insulating resin layer 24 First through-hole magnetic body 25 Through-hole magnetic body 26 first extraction electrode 27 second extraction electrode 28 first external electrode 29 second external electrode 30 first side electrode 31 second side electrode Dm dummy terminal electrode F solder fillet Tm coil Conductor intermediate turn To Coil conductor outermost turn

Claims (4)

A surface mount type coil component,
A substrate,
First and second spiral conductors respectively formed on one and other main surfaces of the substrate;
A first terminal electrode formed on the one main surface and connected to an outer peripheral end of the first spiral conductor;
A second terminal electrode formed on the other main surface and connected to an outer peripheral end of the second spiral conductor;
A first through-hole conductor connecting the inner peripheral ends of the first and second spiral conductors through the substrate;
A first dummy terminal electrode formed on the one main surface and provided at a position overlapping the second terminal electrode in plan view;
A second dummy terminal electrode formed on the other main surface and provided at a position overlapping the first terminal electrode in plan view;
A second through-hole conductor that passes through the substrate and connects the first dummy terminal electrode and the second terminal electrode;
A first metal magnetic powder-containing resin layer formed on the one main surface and covering the first spiral conductor, the first terminal electrode, and the first dummy terminal electrode;
A second metal magnetic powder-containing resin layer formed on the other main surface and covering the second spiral conductor, the second terminal electrode, and the second dummy terminal electrode;
A first extraction electrode that penetrates the first metal magnetic powder-containing resin layer and is connected to the upper surface of the first terminal electrode;
A second lead electrode penetrating the first metal magnetic powder-containing resin layer and connected to the upper surface of the first dummy terminal electrode;
The outer side surfaces of the first and second terminal electrodes, the first and second dummy terminal electrodes, and the first and second extraction electrodes are covered with the first and second magnetic powder-containing resins. Exposed without being exposed,
Side surfaces of the substrate that are coplanar with the outer side surfaces of the first and second terminal electrodes are not covered with the first and second metal magnetic powder-containing resin layers, and the first and second terminal electrodes are not covered with the first and second metal magnetic powder-containing resin layers. A coil component that is exposed together with the outer side surface of the terminal electrode. The substrate has first and second side surfaces parallel to each other, and third and fourth side surfaces orthogonal to the first and second side surfaces,
The first side surface of the substrate is flush with an outer side surface of the first terminal electrode and an outer side surface of the second dummy terminal electrode;
The coil component according to claim 1, wherein the second side surface of the substrate is flush with an outer side surface of the second terminal electrode and an outer side surface of the first dummy terminal electrode. A through-hole magnetic body that penetrates through a corner of the substrate and connects the first magnetic powder-containing resin layer and the second magnetic powder-containing resin layer;
The coil component according to claim 1 or 2, wherein the first and second side surfaces of the substrate are provided in a region excluding the formation region of the through-hole magnetic body. First and second external electrodes formed on the main surface of the first metal magnetic powder-containing resin layer and connected to the first and second extraction electrodes, respectively.
The first external electrode constitutes a first L-shaped electrode together with the first extraction electrode, the first terminal electrode, and the first dummy terminal electrode,
4. The device according to claim 1, wherein the second external electrode forms a second L-shaped electrode together with the second extraction electrode, the second terminal electrode, and the second dummy terminal electrode. 5. The coil component according to one item.

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