JP2012248628A - Manufacturing method of coil component and coil component - Google Patents

Abstract

A conductor other than a lead conductor is prevented from being exposed on a side surface of a coil component after being separated by dicing.
In the coil component forming step, a through hole for embedding a conductor is formed in each of first to seventh rectangular regions A1 to A7, and an inner peripheral edge is formed for each rectangular region with respect to a front surface 2t of the substrate. Forms a planar spiral conductor covering the through hole for embedding a conductor, and four planar spiral conductors corresponding to these rectangular areas are formed in areas where the corners of the first to fourth rectangular areas A1 to A4 are gathered. A lead conductor 11a connected to each outer peripheral end is formed, and a planar spiral conductor whose inner peripheral end covers the through hole for embedding the conductor is formed for each rectangular region with respect to the back surface 2b of the substrate. In the region where the corners of the fifth to seventh rectangular regions A1, A5 to A7 are gathered, the lead conductor 11b connected to the outer peripheral ends of the four planar spiral conductors corresponding to these rectangular regions is formed. To.
[Selection] Figure 3

Description

  The present invention relates to a method for manufacturing a coil component and a coil component, and more particularly to a method for manufacturing a coil component having a planar spiral conductor formed on a printed board by electrolytic plating and such a coil component.

  In the field of consumer or industrial electronic devices, surface mount type coil components are often used as inductors for power supplies. This is because the surface mount type coil component is small and thin, has excellent electrical insulation, and can be manufactured at low cost.

  One of the specific structures of surface mount type coil components is a planar coil structure that applies printed circuit board technology. To briefly explain this structure from the viewpoint of the manufacturing process, a planar spiral seed layer (underlying film) is first formed on a printed circuit board. Then, the metal ions in the plating solution are electrodeposited on the seed layer by dipping in the plating solution and flowing a direct current (hereinafter referred to as “plating current”) through the seed layer. As a result, a planar spiral conductor is formed, and then an insulating resin layer covering the formed planar spiral conductor, a protective layer, and a metal magnetic powder-containing resin layer as a magnetic path are sequentially formed to complete a coil component. According to this structure, the accuracy of dimensions and positions can be maintained at a very high value, and the size and thickness can be reduced. Patent Document 1 discloses a planar coil element having such a planar coil structure.

JP 2006-310716 A

  By the way, when mass-producing coil parts having a planar coil structure, a large number of coil parts are formed in a matrix on a single large insulating substrate, and then individual coil parts are manufactured through a separation process by dicing. become. Accordingly, each coil component is not separated at the stage of electrolytic plating, and a plating current flows through the seed layer from the end of one large insulating substrate.

  Here, FIG. 10 is a plan view of a coil component according to the background art of the present invention. This figure shows the front surface of the substrate in a state immediately after the end of electrolytic plating (before separation). The broken line shown in the figure is a cutting line for dicing. The region 104 is a hole for embedding a metal magnetic powder-containing resin layer later to form a magnetic path. As shown in the figure, a large number of substantially elliptical planar spiral conductors 100 are formed in a matrix on the front surface of the substrate, and the outer peripheral end thereof is one side in the y direction by a planar conductor 101 that later becomes a lead conductor. It is connected to another planar spiral conductor 100 adjacent to the side. Although not shown, the same planar spiral conductor 100 is also formed in a matrix on the back surface of the substrate. The front surface spiral conductor 100 and the back surface planar conductor 100 are a through-hole conductor. The inner peripheral ends are connected by 102. On the back surface, a planar conductor 101 is formed on the opposite side of the y direction with respect to the planar conductor 101 on the front surface across the planar spiral conductor 100, and the planar spiral conductor 100 on the back surface is connected to the planar conductor 101. And is connected to another planar spiral conductor 100 adjacent to the other side in the y direction. This makes it possible to flow a plating current in the y direction during electrolytic plating.

  Furthermore, as shown in FIG. 10, each planar conductor 101 is also connected to two planar conductors 101 adjacent to each other in the x direction via a straight conductor 103. The same applies to the back surface (not shown). By adopting such a structure, it is possible to flow a plating current also in the x direction during electrolytic plating.

  In this way, the plating current flowing in both the x direction and the y direction is an indispensable matter for performing uniform plating. However, the linear conductor 103 as in the background art has a problem that its end face is exposed to the side surface of the coil component after being separated into individual coil components by dicing. Such exposure is not preferable because it causes plating elongation to occur in the external terminal plating step performed after separation or adversely affects use reliability after mounting.

  Accordingly, one of the objects of the present invention is to provide a method of manufacturing a coil component and a coil component that can prevent a conductor other than the lead conductor from being exposed to the side surface after separation.

  In order to achieve the above object, a coil component manufacturing method according to the present invention includes a coil component forming step of forming a plurality of coil components in a matrix on a single substrate, and cutting the substrate for each of the plurality of coil components. The coil component forming step includes: a first rectangular region defined on the substrate; and a first rectangular region adjacent to the first rectangular region on one side in a first direction within the substrate surface. Two rectangular regions, a third rectangular region adjacent to the second rectangular region on one side of the first direction and a second direction intersecting at right angles within the substrate surface, one side of the second direction A fourth rectangular region adjacent to the first rectangular region, a fifth rectangular region adjacent to the first rectangular region on the other side in the first direction, and the other side in the second direction on the other side. A sixth rectangular area adjacent to the fifth rectangular area; and the second rectangular area Forming a through hole for embedding a conductor in each of the seventh rectangular regions adjacent to the first rectangular region on the other side in the direction, and the first to seventh elements with respect to the front surface of the substrate For each rectangular area, a first planar spiral conductor whose inner peripheral end covers the through hole for burying the conductor is formed, and the first to fourth rectangular areas are gathered in an area where the corners gather. Forming a first lead conductor connected to an outer peripheral end of each of the four first planar spiral conductors corresponding to the first to fourth rectangular regions, and the back surface of the substrate; A region in which each of the rectangular regions of the first and fifth to seventh rectangular regions gathers while forming a second planar spiral conductor whose inner peripheral end covers the conductor-embedded through hole for each rectangular region In addition, the first and fifth to seventh Forming a second lead conductor connected to an outer peripheral end of each of the four second planar spiral conductors corresponding to the shape region, performing an electroplating process, the first and second planar spiral conductors, and the A step of electrodepositing metal ions on the first and second lead conductors, wherein the substrate is separated for each of the first to seventh rectangular regions in the cutting step.

  According to the present invention, it is possible to pass a plating current in both the x direction and the y direction through the first and second lead conductors. Therefore, it is possible to avoid that conductors other than the lead conductor are exposed on the side surface after separation.

  In the coil component manufacturing method, the coil component forming step includes forming the substrate at a corner portion of the first to seventh rectangular regions where none of the first and second lead conductors is formed. And forming a magnetic path forming through hole penetrating through the magnetic path and embedding a magnetic material in the magnetic path forming through hole. According to this, the inductance of the coil component can be improved.

  In the method for manufacturing a coil component, the magnetic path forming through hole may be formed also in a central portion of the planar spiral conductor. According to this, the inductance of the coil component can be further improved.

  In the coil component manufacturing method, the magnetic path forming through-hole may be formed before forming the first and second planar spiral conductors and the first and second lead conductors. According to this, since it is possible to form the first and second planar spiral conductors by projecting into the magnetic path forming through hole, the formation area of the first and second planar spiral conductors is substantially reduced. It becomes possible to take widely.

  In the coil component manufacturing method, the coil component forming step includes forming an insulating resin layer covering the first and second planar spiral conductors and the first and second lead conductors after the electrolytic plating. In the step of embedding the magnetic body, the magnetic material is formed by forming a metal magnetic powder-containing resin layer that covers the front surface and the back surface of the substrate and fills the magnetic path forming through hole. A magnetic material may be embedded in the through hole for forming a path. According to this, it is possible to obtain a power choke coil having excellent direct current superposition characteristics.

  In the method of manufacturing a coil component, the first and second planar spiral conductors each correspond to the second lead conductor corresponding to the corresponding first lead conductor among the two diagonal lines of the corresponding rectangular region. It is good also as having a shape comparatively long in the direction of one diagonal which connects a conductor, and relatively short in the direction of the other diagonal. This makes it possible to increase the coil area.

  The coil component manufacturing method according to one aspect of the present invention includes a coil component forming step of forming a plurality of coil components in a matrix on a single substrate, and cutting for cutting the substrate for each of the plurality of coil components. A first cutting line extending in a first direction and alternately arranged in a second direction perpendicular to the first direction, and in the cutting step, respectively, Cutting the substrate along third and fourth cutting lines that extend in a second direction and are alternately arranged in the first direction, and the coil component forming step includes: Forming a through hole for embedding a conductor in each of the rectangular regions surrounded by the cutting line, and an inner peripheral edge of each of the rectangular regions surrounded by the cutting line in the cutting step with respect to the front surface of the substrate Covers the through hole for embedding the conductor. Are formed at the intersection of the first cutting line and the third cutting line and connected to the outer peripheral ends of the four first planar spiral conductors arranged around the intersection. A step of forming a first lead conductor, and a second surface of the back surface of the substrate, the inner peripheral end of which covers the through hole for embedding the conductor in each rectangular region surrounded by the cutting line in the cutting step A planar spiral conductor is formed and connected to an outer peripheral end of each of the four second planar spiral conductors arranged around the intersection at the intersection of the second cutting line and the fourth cutting line. A step of forming two lead conductors and a step of performing electroplating to electrodeposit metal ions on the first and second planar spiral conductors and the first and second lead conductors. To. Even in this case, it is possible to pass a plating current in both the x direction and the y direction through the first and second lead conductors. Therefore, it is possible to avoid that conductors other than the lead conductor are exposed on the side surface after separation.

  The coil component according to the present invention includes a substantially rectangular substrate having first to fourth corners in the clockwise direction, and a first planar spiral conductor formed on the front surface of the substrate by electrolytic plating. A second planar spiral conductor formed on the back surface of the substrate by electrolytic plating, and an inner peripheral end of the first planar spiral conductor and an inner circumference of the second planar spiral conductor that penetrates the substrate. A through-hole conductor connecting the end and a first in-plane region including the first corner portion formed by electrolytic plating on the front surface and connected to the outer peripheral end of the first planar spiral conductor A lead conductor and a second lead conductor formed by electrolytic plating in a region in the back surface including the third corner portion and connected to an outer peripheral end of the second planar spiral conductor. And

  By adopting such a structure for the coil component, it is possible to flow a plating current in both the x direction and the y direction through the first and second lead conductors when the coil component is mass-produced. Therefore, it can be avoided that a conductor other than the lead conductor is exposed on the side surface of the coil component.

  The coil component may further include first and second through-hole magnetic bodies that respectively penetrate the portion including the second corner portion and the portion including the fourth corner portion of the substrate. According to this, the inductance of the coil component can be improved.

  The coil component may further include a third through-hole magnetic body penetrating through a portion of the substrate corresponding to a central portion of the first and second planar spiral conductors. According to this, the inductance of the coil component can be further improved.

  In the coil component, an insulating resin layer covering the first and second planar spiral conductors and the first and second lead conductors, and a metal magnetic powder-containing resin layer covering the front surface and the back surface of the substrate. The first to third through-hole magnetic bodies may be part of the metal magnetic powder-containing resin layer. According to this, it is possible to obtain a power choke coil having excellent direct current superposition characteristics.

  In the coil component, the first and second planar spiral conductors are relatively long in a direction of a diagonal line connecting the first corner and the third corner, and the second corner and the second It is good also as having a relatively short shape in the direction of the diagonal line connecting the fourth corners. This makes it possible to increase the coil area.

  According to the present invention, it is possible to pass a plating current in both the x direction and the y direction through the first and second lead conductors. Therefore, it is possible to avoid that conductors other than the lead conductor are exposed on the side surface after separation.

It is a disassembled perspective view of the coil components by embodiment of this invention. It is a figure which shows the coil components by embodiment of this invention in the middle of a mass production process. (A) is the top view which looked at the board | substrate before a cutting | disconnection from the front surface side, (b) is the sectional view on the AA line of (a). (A) and (b) are the layout of each structure at the time of seeing the board | substrate before a cutting | disconnection from the front surface side, respectively, and the layout of each structure at the time of seeing the board | substrate before a cutting | disconnection from the back surface side. . It is a figure which shows the coil components by embodiment of this invention in the middle of a mass production process. (A) is the top view which looked at the board | substrate before a cutting | disconnection from the front surface side, (b) is the sectional view on the AA line of (a). It is a figure which shows the coil components by embodiment of this invention in the middle of a mass production process. (A) is the top view which looked at the board | substrate before a cutting | disconnection from the front surface side, (b) is the sectional view on the AA line of (a). It is a figure which shows the coil components by embodiment of this invention in the middle of a mass production process. (A) is the top view which looked at the board | substrate before a cutting | disconnection from the front surface side, (b) is the sectional view on the AA line of (a). It is a figure which shows the coil components by embodiment of this invention in the middle of a mass production process. (A) is the top view which looked at the board | substrate before a cutting | disconnection from the front surface side, (b) is the sectional view on the AA line of (a). It is a figure which shows the coil components by embodiment of this invention after dividing into pieces. It is a top view of the coil components by the modification of embodiment of this invention. It is a top view of the coil component by the background art of this invention.

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

FIG. 1 is an exploded perspective view of a coil component 1 according to the present embodiment. As shown in the figure, the coil component 1 has a substantially rectangular substrate 2. The “substantially rectangular” is intended to include a complete rectangle and a rectangle lacking some corners. In this specification, the term “corner” of a rectangle is used. However, the “corner” for a rectangle lacking some corners means the corner of a complete rectangle obtained when there is no lack. means. Hereinafter, the four corners of the substrate 2 are referred to as _first to _fourth corners C _{1 to} C ₄ counterclockwise as shown in FIG.

  As a material for the substrate 2, it is preferable to use a general printed circuit board in which a glass cloth is impregnated with an epoxy resin. Further, for example, a BT resin base material, an FR4 base material, or an FR5 base material may be used.

  A planar spiral conductor 10a (first planar spiral conductor) is formed at the center of the front surface 2t of the substrate 2. Similarly, a planar spiral conductor 10b (second planar spiral conductor) is formed at the center of the back surface 2b. The substrate 2 is provided with through holes 12a (through holes for embedding conductors), and the through hole conductors 12 are embedded therein. The inner peripheral end of the planar spiral conductor 10 a and the inner peripheral end of the planar spiral conductor 10 b are connected to each other by a through-hole conductor 12.

  Here, the planar spiral conductor 10a and the planar spiral conductor 10b are wound in opposite directions. That is, the planar spiral conductor 10a viewed from the front surface 2t side is wound clockwise from the inner peripheral end to the outer peripheral end, but similarly viewed from the front surface 2t side. The planar spiral conductor 10b is wound counterclockwise from the inner peripheral end toward the outer peripheral end. By adopting such a winding method, in the coil component 1, when a current is passed between the outer peripheral end of the planar spiral conductor 10a and the outer peripheral end of the planar spiral conductor 10b, both the planar spiral conductors are identical to each other. Generate a magnetic field in the direction and strengthen each other. Therefore, the coil component 1 functions as one inductor.

The planar spiral conductor 10a, 10b, respectively, relatively long in the diagonal direction connecting the first corner C ₁ and the third corner C _3, second corner C ₂ and the fourth corner relatively short in the direction of the diagonal line connecting the C _4, and has a slightly distorted shape. This point will be described again in more detail later when the manufacturing process of the coil component 1 is described later.

Lead conductors 11a and 11b are formed on the front surface 2t and the back surface 2b of the substrate 2, respectively. Lead conductor 11a (first lead conductor) is formed in a region in the front surface 2t comprising first corner C _1. On the other hand, lead conductor 11b (second lead conductor) is formed in a region in the back surface 2b including a third corner C _3. The lead conductor 11a is connected to the outer peripheral end of the flat spiral conductor 10a, and the lead conductor 11b is connected to the outer peripheral end of the flat spiral conductor 10b.

  The planar spiral conductors 10a and 10b and the lead conductors 11a and 11b are formed through two electrolytic plating processes after forming an underlayer by an electroless plating process. It is preferable that the material of the underlayer and the material of the plating layer formed in the two electrolytic plating processes are both Cu. The main object of the present invention is to allow a plating current to flow in both the x direction and the y direction in the second electrolytic plating process. This point will be described again in more detail when the manufacturing process of the coil component 1 is described later.

  The planar spiral conductors 10 a and 10 b and the lead conductors 11 a and 11 b are covered with an insulating resin layer 21. The insulating resin layer 21 is provided to prevent conduction between each conductor and a metal magnetic powder-containing resin layer 22 described later.

  The front surface 2 t and the back surface 2 b of the substrate are further covered with a metal magnetic powder-containing resin layer 22 from above the insulating resin layer 21. The metal magnetic powder-containing resin layer 22 is made of a magnetic material (metal magnetic powder-containing resin) made by mixing metal magnetic powder into a resin. As the metal magnetic powder, it is preferable to use a permalloy material. Specifically, a weight ratio of 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, for example, 70:30 to 80:20. It is preferable to use a metal magnetic powder containing a weight ratio of 75:25. The metal magnetic powder content in the metal magnetic powder-containing resin layer 22 is preferably 90 to 96% by weight. On the other hand, it is preferable to use a liquid or powder epoxy resin as the resin. Moreover, it is preferable that the resin content rate in the metal magnetic powder containing resin layer 22 is 4 to 10 weight%. The resin functions as an insulating binder. The metal magnetic powder-containing resin layer 22 having the above configuration is such that the smaller the amount of metal magnetic powder relative to the resin, the smaller the saturation magnetic flux density, and conversely, the larger the amount of metal magnetic powder, the larger the saturation magnetic flux density. It has properties.

Further, three through holes 14 (magnetic path forming through holes) are formed in the substrate 2 as shown in FIG. Two of them are provided through the portion of the substrate 2 including the second and fourth corners C ₂ and C ₄ , and the other one is the planar spiral conductor 10 a, of the substrate 2. It is provided through a portion corresponding to the central portion of 10b. The metal magnetic powder-containing resin layer 22 is also embedded in these through holes 14, and corresponds to the _fourth corner C4 of the embedded metal magnetic powder-containing resin layer 22, as shown in FIG. The portion constitutes the first through-hole magnetic body 22a, the portion corresponding to the _second corner C2 constitutes the second through-hole magnetic body 22b, and corresponds to the central portion of the planar spiral conductors 10a and 10b. The portion constitutes a third through-hole magnetic body 22c.

  By providing the metal magnetic powder-containing resin layer 22 as described above, a complete closed magnetic circuit is formed in the coil component 1. Further, since the metal magnetic powder-containing resin layer 22 has the properties as described above, the saturation magnetic flux density of the closed magnetic circuit can be reduced by adjusting the content of the metal magnetic powder in the metal magnetic powder-containing resin layer 22. It is possible to adjust.

  Although not shown in FIG. 1, a thin insulating layer is formed on the surface of the metal magnetic powder-containing resin layer 22. The insulating layer is formed by treating the surface of the metal magnetic powder-containing resin layer 22 with phosphate. The reason why this insulating layer is provided is to avoid conduction between external electrodes 25 and 26 described later and the metal magnetic powder-containing resin layer 22.

  External electrodes 25 and 26 are formed on the side surfaces of the coil component 1. The external electrodes 25 and 26 are in contact with the lead conductors 11a and 11b exposed on the side surfaces, respectively. Therefore, the external electrode 25 is electrically connected to the lead conductor 11a, and the external electrode 26 is electrically connected to the lead conductor 11b. The external electrodes 25 and 26 and the metal magnetic powder-containing resin layer 22 are not electrically connected due to the presence of the thin insulating layer described above. As shown in FIG. 1, the external electrodes 25 and 26 preferably have a shape that covers all exposed surfaces of the lead conductors 11a and 11b. The external electrodes 25 and 26 are bonded to a wiring formed on a mounting substrate (not shown) by solder or the like. Thereby, it is realized that a current flows between the outer peripheral end of the planar spiral conductor 10a and the outer peripheral end of the planar spiral conductor 10b through the wiring formed on the mounting substrate.

  By adopting the structure as described above for the coil component 1, in the electrolytic plating process (the second electrolytic plating process described above) when the coil component 1 is mass-produced, the x direction and the y direction are drawn through the lead conductors 11a and 11b. Plating current can be passed in both directions. Hereinafter, this point will be described in detail while explaining the mass production process of the coil component 1.

  2 and 4 to 8 are views showing the coil component 1 in the middle of the mass production process. Of these figures, (a) in each drawing excluding FIG. 8 is a plan view of the substrate 2 before cutting as viewed from the front surface 2t side, and (b) is a sectional view taken along line AA in (a). . In addition, the broken line shown to (a) of each figure except FIG. 8 has shown the cutting line in a dicing process. Each area surrounded by the cutting line is an individual coil component 1. FIG. 8 is a cross-sectional view of the coil component 1 thus separated. The cross section shown in the figure corresponds to the lower half of the line AA in FIG.

  3 (a) and 3 (b) are layout diagrams of respective components when the substrate 2 before cutting is viewed from the front surface 2t side, and when the substrate 2 before cutting is viewed from the back surface 2b side. The arrangement | positioning figure of each structure of is shown. In these drawings, the planar spiral conductors 10a and 10b are omitted. Also in these drawings, the broken line shows the cutting line in the subsequent dancing process.

  As shown in FIGS. 3A and 3B, a large number of rectangular regions are defined on the substrate 2 by cutting lines. These rectangular areas have a repetitive structure with the first to seventh rectangular areas A1 to A7 shown in FIGS. 3A and 3B as one unit. The positional relationship between the first rectangular area A1 and the other rectangular areas will be described. First, the second rectangular area A2 is the first rectangular area on one side in the x direction (first direction) in the surface of the substrate 2. Adjacent to A1. The third rectangular area A3 is adjacent to the second rectangular area A2 on one side in the x direction and the y direction (second direction) that intersects at right angles within the surface of the substrate 2. The fourth rectangular area A4 is adjacent to the first rectangular area A1 on one side in the y direction. The fifth rectangular area A5 is adjacent to the first rectangular area A1 on the other side in the x direction. The sixth rectangular area A6 is adjacent to the fifth rectangular area A5 on the other side in the y direction. Finally, the seventh rectangular area A7 is adjacent to the first rectangular area A1 on the other side in the y direction. Hereinafter, the mass production process of the coil component 1 will be described with reference to these rectangular regions, but before that, referring to FIGS. 3A and 3B, these rectangular regions, the lead conductors 11a and 11b, and the magnetic parts are described. The planar positional relationship with the through hole 14 for forming a path will be described.

  First, as shown in FIG. 3A, the lead conductor 11a is formed in a region where the corners of the first to fourth rectangular regions A1 to A4 gather on the front surface 2t of the substrate 2. . Although not shown in FIG. 3, a planar spiral conductor 10a is formed for each of the first to seventh rectangular regions A1 to A7 on the front surface 2t, and the lead conductor 11a is disposed so as to surround itself. It is comprised so that it may connect with each outer peripheral end of four planar spiral conductors corresponding to 1st thru | or 4th rectangular area | region A1-A4.

  On the other hand, as shown in FIG. 3B, the lead conductor 11b is formed in a region where the corners of the first and fifth to seventh rectangular regions A1, A5 to A7 gather on the back surface 2b of the substrate 2. It is formed. Although not shown in FIG. 3, a planar spiral conductor 10b is formed for each of the first to seventh rectangular regions A1 to A7 on the back surface 2b, and the lead conductor 11b is a first conductor disposed so as to surround itself. And it is comprised so that it may connect with the outer periphery end of each of the four planar spiral conductors corresponding to 5th thru | or 7th rectangular area | region A1, A5-A7.

  The through hole 14 for forming a magnetic path is formed at a corner where none of the lead conductors 11a and 11b is formed among the corners of the first to seventh rectangular regions A1 to A7. Since the through hole 14 penetrates the substrate 2, it cannot be formed in a region where one of the lead conductors 11 a and 11 b is formed.

  From another viewpoint, the planar positional relationship among the rectangular region, the lead conductors 11a and 11b, and the magnetic path forming through hole 14 will be described again. As shown in FIG. 3, cutting lines x1, x2 (first and second cutting lines) are alternately arranged in the y direction on the surface of the substrate 2, and cutting lines y1, y2 (third and fourth lines) are arranged. Cutting lines) are alternately arranged in the y direction. The lead conductor 11a is disposed at the intersection of the cutting line x1 and the cutting line y1, and is configured to connect to the outer peripheral ends of the four planar spiral conductors disposed so as to surround the intersection. On the other hand, the lead conductor 11b is arranged at the intersection of the cutting line x2 and the cutting line y2, and is configured to be connected to the outer peripheral ends of the four planar spiral conductors arranged so as to surround the intersection. The through hole 14 for forming a magnetic path is disposed at the intersection between the cutting line x1 and the cutting line y2 and at the intersection between the cutting line x2 and the cutting line y1.

  Now, the mass production process of the coil component 1 will be described with reference to FIGS. 2 and 4 to 8. The following description focuses on only the first to seventh rectangular areas A1 to A7, but the same applies to other rectangular areas.

  First, as shown in FIG. 2, the substrate 2 is provided with a through hole 12a for burying a conductor and a through hole 14 for forming a magnetic path. One through hole 12a is provided in each of the first to seventh rectangular regions A1 to A7. As for the through hole 14, as described above, of the corners of the first to seventh rectangular regions A1 to A7, the corner where none of the lead conductors 11 a and 11 b is formed (the intersection of the cutting line x1 and the cutting line y2). And one at the intersection of the cutting line x2 and the cutting line y1) and at the center of the planar spiral conductors 10a and 10b.

  Next, as shown in FIG. 4, the planar spiral conductor 10a whose inner peripheral end covers the through hole 12a is formed for each of the first to seventh rectangular regions A1 to A7 on the front surface 2t of the substrate 2. . In addition, the lead conductor 11a is formed at the above-described position (region where the corners of the first to fourth rectangular regions A1 to A4 are gathered, the intersection of the cutting line x1 and the cutting line y1). At this time, the outer peripheral ends of the four planar spiral conductors 10a corresponding to the first to fourth rectangular regions A1 to A4 are connected to the lead conductor 11a.

  Similarly, on the back surface 2b of the substrate 2, a planar spiral conductor 10b whose inner peripheral end covers the through hole 12a is formed for each of the first to seventh rectangular regions A1 to A7. In addition, the lead conductor 11b is formed at the above-described position (region where the corners of the fifth to seventh rectangular regions A1, A5 to A7 are gathered; the intersection of the cutting line x2 and the cutting line y2). At this time, the outer peripheral ends of the four planar spiral conductors 10b corresponding to the fifth to seventh rectangular regions A1, A5 to A7 are connected to the lead conductor 11b.

  A specific method for forming the planar spiral conductors 10a and 10b and the lead conductors 11a and 11b is as follows. That is, first, a Cu underlayer is formed on both surfaces of the substrate 2 by electroless plating, and a photoresist layer is electrodeposited on the surface of the underlayer. This underlayer is also formed in the through hole 12 a and constitutes the through hole conductor 12. Subsequently, an opening pattern (negative pattern) in the shape of the planar spiral conductors 10a and 10b and the lead conductors 11a and 11b is provided in the photoresist layer by photolithography on each side. Then, after forming a plating layer in the opening pattern by electrolytic plating and removing the photoresist layer, the underlying layer other than the portion where the plating layer is formed is removed by etching. The electrolytic plating step here corresponds to the first electrolytic plating step described above. Here, since the base layer is an unpatterned plate-like conductor, there is no problem regarding the direction in which the plating current flows. Through the above-described steps, the planar spiral conductors 10a and 10b and the lead conductors 11a and 11b respectively formed of the base layer and the plating layer are formed.

  The conductors formed on the front surface 2t and the back surface 2b of the substrate 2 in the steps so far serve as seed layers in the second electrolytic plating step described later. Since the seed layer is connected to both the x direction and the y direction through the lead conductors 11a and 11b and the through-hole conductor 12, a plating current is passed in both the x direction and the y direction in the second electrolytic plating process. It becomes possible.

Here, as shown in FIG. 4, in the planar spiral conductor 10a, the length L in the direction of one diagonal line connecting the corresponding lead conductor 11a and the corresponding lead conductor 11b among the two diagonal lines in the corresponding rectangular region. ₁ is longer than the length L ₂ in the direction of the other diagonal line. Although not shown, the same applies to the planar spiral conductor 10b. As a result, the shapes of the planar spiral conductors 10a and 10b are slightly distorted. By doing so, it is possible to effectively use the substrate surface and increase the coil area.

  Now, as shown in FIG. 5, a second electrolytic plating process is performed. Specifically, the substrate 2 is immersed in the plating solution while a plating current is passed from the end portion of the substrate 2 before cutting to each conductor as a seed layer. At this time, as described above, since the seed layer is connected in both the x direction and the y direction, the plating current flows in both the x direction and the y direction. Thereby, metal ions are uniformly electrodeposited on the planar spiral conductors 10a and 10b and the lead conductors 11a and 11b, and the plating layer 20 having a uniform film thickness is formed.

  By forming the plating layer 20, as shown in FIG. 5B, the film thickness of each conductor can be significantly increased. The reason why a large film thickness is ensured in this way is that the coil component 1 according to the present embodiment is an inductor for power supply and it is necessary to realize a very small DC resistance.

  After the second electrolytic plating treatment, an insulating resin is formed on both surfaces of the substrate 2, and each conductor and the plating layer 20 are covered with an insulating resin layer 21 as shown in FIG. At this time, the side wall of the through hole 14 is also covered with the insulating resin layer 21, but it is necessary to prevent the entire area of the through hole 14 from being completely filled with the insulating resin layer 21.

  Next, as shown in FIG. 7, both surfaces of the substrate 2 are covered with a metal magnetic powder-containing resin layer 22. A specific forming method will be described. First, a UV tape (not shown) for suppressing warpage of the substrate 2 is pasted on the back surface 2b of the substrate 2, and a resin paste containing metal magnetic powder is screen printed on the front surface 2t. To do. A heat release tape may be used instead of the UV tape. It is preferable to use a screen sheet made of a metal magnetic powder-containing resin paste having a thickness of about 0.27 mm. Further, after the screen printing, the paste is temporarily cured through defoaming and heating at 80 ° C. for 30 minutes. Subsequently, the UV tape is peeled off, and a metal magnetic powder-containing resin paste is screen-printed on the back surface 2b. Again, it is preferable to use a screen sheet made of a metal magnetic powder-containing resin paste having a thickness of about 0.27 mm. Further, after screen printing, the paste is fully cured by heating at 160 ° C. for 1 hour. The metal magnetic powder containing resin layer 22 is completed by the above process.

  In the above process, the metal magnetic powder-containing resin layer 22 is also embedded in the through hole 14. As a result, the first to third through-hole magnetic bodies 22 a to 22 c shown in FIG. 1 are formed in the through-hole 14.

  Finally, the substrate 2 is cut along a cutting line using a dicer. As a result, the individual coil components 1 are obtained for each rectangular region. Next, as shown in FIG. 8, an insulating layer 23 is formed on the surface of the metal magnetic powder-containing resin layer 22. The insulating layer 23 is formed by treating the surface of the metal magnetic powder-containing resin layer 22 with phosphate. Thereafter, the external electrodes 25 and 26 shown in FIG. 1 are formed by sputtering or the like, and the coil component 1 is finally completed.

  As described above, according to the manufacturing method of the coil component 1 according to the present embodiment, it is possible to flow a plating current in both the x direction and the y direction through the lead conductors 11a and 11b during mass production. . Therefore, it is possible to avoid that conductors other than the lead conductor are cut off and exposed to the side surfaces after the plating current flows in both the x direction and the y direction.

  Further, the first and second through-hole magnetic bodies 22a and 22b are formed at the corners where neither of the lead conductors 11a and 11b is formed, and further, the portions corresponding to the central portions of the planar spiral conductors 10a and 10b are also formed. Since the third through-hoe magnetic body 22c is formed, the inductance of the coil component can be improved as compared with the case where these are not formed.

  Further, since the through hole 14 for forming the magnetic path is formed before the planar spiral conductors 10a and 10b and the lead conductors 11a and 11b are formed, as shown in FIG. Thus, the planar spiral conductors 10a and 10b can be formed. Therefore, it becomes possible to make the formation area of the planar spiral conductors 10a and 10b substantially wide.

  In addition, since the magnetic path is formed not by the magnetic substrate but by the metal magnetic powder-containing resin layer 22, it is possible to obtain a power choke coil having excellent direct current superposition characteristics.

  Further, since the planar spiral conductors 10a and 10b are formed by being slightly distorted, it is possible to increase the coil area.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to such embodiment at all, and this invention can be implemented in various aspects in the range which does not deviate from the summary. Of course.

  For example, the shape of the lead conductors 11a and 11b does not necessarily have to be a rectangular shape (including a rounded rectangular shape) as shown in FIGS. 1 to 7. For example, as shown in FIG. It is good also as a shape which removed the corner | angular part in the fan shape. According to this, since the planar spiral conductor can be formed also on the removed fan-shaped portion, it is possible to widen the formation area of the planar spiral conductors 10a and 10b.

A1~A7 first to front surface 2t substrate 2 Noura surface of the rectangular regions _C 1 -C ₄ corner portion 22a~22c first to third through-hole magnetic body 1 coil device 2 substrate 2b substrate 2 of the 7 10a, 10b Planar spiral conductors 11a, 11b Lead conductor 12 Through hole conductor 12a Conductor embedding through hole 14 Magnetic path forming through hole 20 Plating layer 21 Insulating resin layer 22 Metal magnetic powder-containing resin layers 22a-22c First to second 3 through-hole magnetic material 23 Insulating layers 25, 26 External electrode

Claims (12)

A coil component forming step of forming a plurality of coil components in a matrix on a single substrate;
A cutting step of cutting the substrate for each of the plurality of coil components,
The coil component forming step includes:
A first rectangular region partitioned by the substrate; a second rectangular region adjacent to the first rectangular region on one side of the substrate surface in the first direction; the first direction and the substrate surface; A third rectangular region adjacent to the second rectangular region on one side in a second direction intersecting at right angles within the first rectangular region, and a fourth rectangle adjacent to the first rectangular region on one side in the second direction. A region, a fifth rectangular region adjacent to the first rectangular region on the other side in the first direction, a sixth rectangular region adjacent to the fifth rectangular region on the other side in the second direction, And forming a through hole for embedding a conductor in each of the seventh rectangular regions adjacent to the first rectangular region on the other side in the second direction;
With respect to the front surface of the substrate, for each of the first to seventh rectangular regions, a first planar spiral conductor whose inner peripheral end covers the through hole for burying a conductor is formed, and the first to seventh The first lead conductors connected to the outer peripheral ends of the four first planar spiral conductors corresponding to the first to fourth rectangular areas are formed in an area where the corners of the four rectangular areas are gathered. Process,
With respect to the back surface of the substrate, for each of the first to seventh rectangular regions, a second planar spiral conductor whose inner peripheral end covers the conductor-embedded through hole is formed, and the first and fifth to fifth regions are formed. The second lead connected to the outer peripheral ends of the four second planar spiral conductors corresponding to the first and fifth to seventh rectangular areas in the area where the corners of the seventh rectangular area are gathered Forming a conductor;
Performing an electrolytic plating process, and electrodepositing metal ions on the first and second planar spiral conductors and the first and second lead conductors,
In the cutting step, the substrate is cut for each of the first to seventh rectangular regions. A method of manufacturing a coil component, wherein: The coil component forming step includes:
Forming a magnetic path forming through-hole penetrating the substrate at a corner where none of the first and second lead conductors is formed among the corners of the first to seventh rectangular regions;
The method for manufacturing a coil component according to claim 1, further comprising: embedding a magnetic body in the through hole for forming a magnetic path. The method for manufacturing a coil component according to claim 2, wherein the magnetic path forming through hole is also formed in a central portion of the planar spiral conductor. 4. The magnetic path forming through hole is formed before forming the first and second planar spiral conductors and the first and second lead conductors. 5. Manufacturing method of coil parts. The coil component forming step includes:
A step of forming an insulating resin layer covering the first and second planar spiral conductors and the first and second lead conductors after the electrolytic plating;
In the step of embedding the magnetic body, the magnetic path forming through is formed by forming a metal magnetic powder-containing resin layer that covers the front surface and the back surface of the substrate and fills the magnetic path forming through hole. The method of manufacturing a coil component according to any one of claims 2 to 4, wherein a magnetic body is embedded in the hole. Each of the first and second planar spiral conductors is in the direction of one diagonal line connecting the corresponding first lead conductor and the second lead conductor among the two diagonal lines of the corresponding rectangular region. 6. The method of manufacturing a coil component according to claim 2, wherein the coil component has a shape that is relatively long and relatively short in the direction of the other diagonal line. A coil component forming step of forming a plurality of coil components in a matrix on a single substrate;
A cutting step of cutting the substrate for each of the plurality of coil components,
In the cutting step, first and second cutting lines each extending in a first direction and alternately arranged in a second direction perpendicular to the first direction, respectively in the second direction Extending the substrate and cutting the substrate along third and fourth cutting lines alternately arranged in the first direction;
The coil component forming step includes:
Forming a through hole for embedding a conductor in each rectangular region surrounded by the cutting line in the cutting step;
With respect to the front surface of the substrate, in each rectangular region surrounded by the cutting line in the cutting step, a first planar spiral conductor whose inner peripheral end covers the through hole for embedding a conductor is formed, and Forming a first lead conductor connected to an outer peripheral end of each of the four first planar spiral conductors arranged around the intersection at the intersection of the first cutting line and the third cutting line; ,
With respect to the back surface of the substrate, a second planar spiral conductor whose inner peripheral end covers the through hole for burying the conductor is formed in each rectangular region surrounded by the cutting line in the cutting step, and the second Forming a second lead conductor connected to an outer peripheral end of each of the four second planar spiral conductors arranged around the intersection at the intersection of the cutting line and the fourth cutting line;
And a step of electrodepositing metal ions on the first and second planar spiral conductors and the first and second lead conductors. A substantially rectangular substrate having first to fourth corners in a clockwise direction;
A first planar spiral conductor formed on the front surface of the substrate by electrolytic plating;
A second planar spiral conductor formed by electrolytic plating on the back surface of the substrate;
A through-hole conductor that passes through the substrate and connects an inner peripheral end of the first planar spiral conductor and an inner peripheral end of the second planar spiral conductor;
A first lead conductor formed by electrolytic plating in a region in the front surface including the first corner portion and connected to an outer peripheral end of the first planar spiral conductor;
A coil component comprising: a second lead conductor formed by electrolytic plating on a region in the back surface including the third corner portion and connected to an outer peripheral end of the second planar spiral conductor. . The first and second through-hole magnetic bodies that respectively penetrate the portion including the second corner portion and the portion including the fourth corner portion of the substrate are further provided. Coil parts. 10. The coil component according to claim 9, further comprising a third through-hole magnetic body that penetrates a portion of the substrate corresponding to a central portion of the first and second planar spiral conductors. An insulating resin layer covering the first and second planar spiral conductors and the first and second lead conductors;
A metal magnetic powder-containing resin layer covering the front and back surfaces of the substrate;
The coil component according to claim 10, wherein the first to third through-hole magnetic bodies are part of the metal magnetic powder-containing resin layer. Each of the first and second planar spiral conductors is relatively long in a diagonal direction connecting the first corner and the third corner, and the second corner and the fourth corner The coil component according to any one of claims 8 to 11, wherein the coil component has a relatively short shape in a direction of a diagonal line connecting the two.

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