JP5765685B2 - Manufacturing method of magnetic element - Google Patents

Description

The present invention includes a coil on the surface of the insulating substrate, a method for manufacturing a magnetic element and a lead-out electrode layer drawn out from the coil.

  The following patent documents disclose an invention relating to a thin film magnetic element used as a planar inductor or the like.

  Patent Documents 1 and 2 disclose a laminated structure in which coils are formed on the upper and lower surfaces of an insulating substrate. However, Patent Document 1 and Patent Document 2 do not disclose the structure of the extraction electrode layer that is electrically connected to the coil.

  On the other hand, although Patent Document 3, Patent Document 4 and Patent Document 5 disclose the structure of the extraction electrode layer, they are formed separately from the coil, and there is a problem that contact resistance increases. Further, in the configuration in which the coils are installed above and below the insulating base material, the contact resistance is also generated between the conductive layers that are electrically connected to each coil through the through holes formed in the insulating base material.

  Conventionally, the coil forming step and the extraction electrode layer forming step are separated, which causes problems such as a decrease in manufacturing efficiency.

JP-A-4-363006 Japanese Patent Laid-Open No. 2000-243637 JP-A-8-115840 JP-A-9-270342 JP 2000-68125 A

The present invention is intended to solve the conventional problems described above, particularly, an object of the invention to provide a method of manufacturing a magnetic element capable of reducing the contact resistance as compared with the prior art.

  Another object of the present invention is to provide a method of manufacturing a magnetic element that can improve the manufacturing efficiency of the coil and the extraction electrode layer.

The manufacturing method of the magnetic element in the present invention is
Preparing an insulating substrate capable of being cut into a plurality of magnetic elements, wherein the first foil body is formed on the upper surface of the insulating base and the second foil body is formed on the lower surface;
A first step of forming a through hole in a position between regions to be each magnetic element of the insulating substrate and forming a through hole in a region to be each magnetic element;
A first plating layer is formed on the first foil body and the second foil body. At this time, a conductive layer is formed by the first plating layer in the through hole, and the first plating body is formed. A second step of forming the first plating layer from the surface of the first foil body to the side wall surface in the through hole and the surface of the second foil body;
Using a photolithography technique, a first coil including the first foil body and the first plating layer is formed on the upper surface side of the insulating base material, and further, the lower surface of the insulating base material is formed. Forming a second coil having the second foil body and the first plating layer on the side;
At this time, the winding start end located inside the first coil and the inside of the second coil and the conductive layer are integrally formed,
Furthermore, a first side surface portion formed on the first side wall surface of the through hole corresponding to the first side surface of the insulating base material, and extending from the first side surface portion to the upper surface of the insulating base material A first upper surface portion integrated with a winding end located outside the first coil, and a first lower surface portion extending from the first side surface portion to the lower surface of the insulating substrate. A second side surface portion formed on a second side wall surface of the through-hole corresponding to a second side surface different from the first side surface of the insulating base, A second extraction electrode layer is formed which extends from the second side surface portion to the lower surface of the insulating substrate and has a second lower surface portion integrated with a winding terminal located outside the second coil. 3 steps,
A fourth step of obtaining a plurality of the magnetic elements by cutting the insulating substrate;
A method of manufacturing a magnetic element that have a,
Between the third step and the fourth step,
A fifth step of forming a second plating layer made of the same material as the first plating layer on the surface of the first plating layer of the first extraction electrode layer and the second extraction electrode layer,
Have
After the fifth step, a sixth step is provided in which a first magnetic layer is provided on the upper surface side of the first coil and a second magnetic layer is provided on the lower surface side of the second coil. And each surface of the first magnetic layer and the first upper surface portion are substantially flush with each other, or the surface of the first upper surface portion is more insulated than the surface of the first magnetic layer. It protrudes in the direction away from the base material, and the surfaces of the second magnetic layer, the first lower surface portion, and the second lower surface portion are substantially the same surface, or the first lower surface portion and the second lower surface portion. Each surface of the lower surface portion is projected in a direction away from the insulating base material than the surface of the second magnetic layer.

The above reporting, the the first extraction electrode layer and the first plated layer in the second extraction electrode layer can be formed by overlapping the second plating layer, a first upper surface portion of the first lead-out electrode layer In addition, the first lower surface portion and the second lower surface portion of the second extraction electrode layer can be formed thicker than each coil. For this reason, when a magnetic layer is provided on the surface side of the coil, the respective surfaces of each magnetic layer, the first extraction electrode layer, and the second extraction electrode layer can be formed on substantially the same surface, or the lower surface portion. And each surface of an upper surface part can be made to protrude from each surface of each magnetic body layer.

  In the present invention, it is preferable that solder lands are formed on the outermost surfaces of the first extraction electrode layer and the second extraction electrode layer.

  In the present invention, the second extraction electrode layer includes the second side surface portion and the second lower surface portion, and extends from the second side surface portion to the upper surface of the insulating base material. It is preferable to form a second upper surface portion having the same structure as the upper surface portion.

According to the method of manufacturing a magnetic element of the present invention, the contact resistance between the first coil and the first extraction electrode layer, the second coil and the second extraction electrode layer, and each coil and the conductive layer is compared with the conventional method. Can be obtained .

  Further, according to the method for manufacturing a magnetic element of the present invention, each coil, conduction layer, and each extraction electrode layer can be formed in the same process, and each coil, conduction layer, and each extraction electrode layer can be integrally formed. Therefore, manufacturing efficiency can be improved.

FIG. 1A is a plan view of a thin inductor according to the present embodiment, in particular, a plan view of a first coil provided on an insulating base material and an upper surface portion of a lead-out electrode layer. FIG. 1B is a diagram showing a second coil provided below by a dotted line, and FIG. 1B is a thin inductor according to the present embodiment as viewed from the direction of the arrow cut along the line AA shown in FIG. FIG.1 (c) is a top view of the lower surface part of the 2nd coil and extraction electrode layer which are provided under an insulating base material. FIG. 2 is a partially enlarged longitudinal sectional view of the thin inductor shown in FIG. FIG. 3A and FIG. 3B are plan views of the first coil and the second coil. FIG. 4 is a longitudinal sectional view of a thin inductor according to another embodiment. FIG. 5A to FIG. 5F are process diagrams (longitudinal sectional views) for explaining a method for manufacturing a thin inductor according to this embodiment.

  FIG. 1A is a plan view of a thin inductor according to the present embodiment, in particular, a plan view of a first coil provided on an insulating base material and an upper surface portion of a lead-out electrode layer. FIG. 1B is a diagram showing a second coil provided below by a dotted line, and FIG. 1B is a thin inductor according to the present embodiment as viewed from the direction of the arrow cut along the line AA shown in FIG. FIG. 1C is a plan view of the lower surface portion of the second coil and the extraction electrode layer provided under the insulating base material, and FIG. 2 is a thin view shown in FIG. It is a partial expanded longitudinal cross-sectional view of an inductor.

  As shown in FIG. 1B, the thin inductor (magnetic element) 10 includes an insulating base material 11, a first coil 12, a second coil 13, a conductive layer 14, and a first extraction electrode layer 15. And a second extraction electrode layer 16 and magnetic sheets (magnetic material layers) 17 and 30.

  Although the material of the insulating base material 11 is not specifically limited, It is suitable that it is a glass epoxy board | substrate combining the copper foil (foil body) of each coil 12 and 13 mentioned later.

  In FIG. 1A, the plane of the insulating base 11 is a square or a rectangle, but the shape is not limited.

  As shown in FIGS. 1A and 1B, the first coil 12 is formed on the upper surface 11 a of the insulating base material 11. In addition, as shown in FIG. 1B, the second coil 13 is formed on the lower surface 11 b of the insulating base material 11.

  As shown in FIG. 1 (a), the first coil 12 is a planar coil wound while being bent at a right angle from the inner winding start end 12a to the outer winding end 12b. As shown in FIG. 1A, in the first coil 12, the first extending direction α1 from the winding start end 12a is the X1 direction.

  Further, as shown in FIG. 1C, the second coil 13 is a planar coil wound while being bent at a right angle from the inner winding start end 13a to the outer winding end 13b. As shown in FIG. 1C, in the second coil 13, the first extending direction α2 from the winding start end 13a is the X2 direction.

  As shown in FIG. 1B, a through hole 11c that penetrates from the upper surface 11a to the lower surface 11b is formed in the approximate center of the insulating base material 11. As shown in FIG. 1B, a conductive layer 14 is provided in the through hole 11c. The conduction layer 14 and the winding start end 12a of the first coil 12 are electrically connected, and the conduction layer 14 and the winding start end 13a of the second coil 13 are electrically connected.

  As shown in FIG. 1B, the first extraction electrode layer 15 is formed on the first side surface (X1 side surface) 11 d side of the insulating base material 11. Further, as shown in FIG. 1B, a second extraction electrode layer 16 is formed on the second side surface (X2 side surface) 11e side of the insulating base 11.

  As shown in FIG. 1B, the first extraction electrode layer 15 includes a first side surface portion 15a formed on the first side surface 11d of the insulating base material 11, and an insulating base material from the first side surface portion 15a. The first upper surface portion 15b extending to the upper surface 11a of the first coil 12 and connected to the winding end 12b of the first coil 12, and the first upper surface portion 15b extending from the first side surface portion 15a to the lower surface 11b of the insulating base 11 And a lower surface portion 15c.

  As shown in FIG. 1A, the first upper surface portion 15 b of the first extraction electrode layer 15 appears on the upper surface 11 a of the insulating material 11. In addition, as shown in FIG. 1C, the first lower surface portion 15 c of the first extraction electrode layer 15 appears on the lower surface 11 b of the insulating base material 11.

  As shown in FIG. 1B, the second extraction electrode layer 16 includes a second side surface portion 16a formed on the second side surface 11e of the insulating base material 11, and an insulating base material from the second side surface portion 16a. A second upper surface portion 16b extending to the upper surface 11a of the first electrode 11 and a second upper surface portion 16b extending from the second side surface portion 16a to the lower surface 11b of the insulating base material 11 and connected to the winding end 13b of the second coil 13. And a lower surface portion 16c. In FIG. 1A, the second side 11e faces the first side 11d in order to make the number of turns of the first coil 12 and the second coil 13 coincide as will be described later. However, when the thin inductor 10 is mounted on the mounting substrate 25, it can be positioned adjacent to the first side surface 11 d according to the position of the wiring pattern of the connection terminal 25 a of the mounting substrate 25. is there.

  As shown in FIG. 1A, the second upper surface portion 16 b of the second extraction electrode layer 16 appears on the upper surface 11 a of the insulating material 11. In addition, as shown in FIG. 1C, the second lower surface portion 16 c of the second extraction electrode layer 16 appears on the lower surface 11 b of the insulating base material 11.

  As shown in FIG. 1B and FIG. 2, the first coil 12 includes a first foil body (for example, copper foil) 18 formed on the upper surface 11 a of the insulating base material 11, and a first foil body 18. It is formed in a laminated structure with a first plating layer 19 formed so as to overlap with the surface 18a of the substrate.

  As shown in FIGS. 1B and 2, the second coil 13 includes a second foil body (for example, a copper foil) 20 formed on the lower surface 11 b of the insulating base material 11, and a second copper foil. 20 is formed in a laminated structure with the first plating layer 19 formed so as to overlap the surface 20a of the substrate 20.

  As shown in FIGS. 1B and 2, the first upper surface portion 15 b of the first extraction electrode layer 15 has the first foil body 18 and the first plating similarly to the first coil 12. It has a laminated structure with the layer 19. In the first upper surface portion 15 b, a laminated structure of the first foil body 18 and the first plating layer 19 is an inner layer 21. Further, as shown in FIGS. 1B and 2, the first lower surface portion 15 c of the first extraction electrode layer 15 is similar to the second coil 13, the second foil body 20, It has a laminated structure with the plating layer 19. In the first lower surface portion 15 c, a laminated structure of the second foil body 20 and the first plating layer 19 is an inner layer 22.

  As shown in FIG. 2, the inner layer 21 of the first upper surface portion 15 b of the first extraction electrode layer 15 and the first coil 12 have substantially the same film thickness, and the first extraction electrode layer 15 has a first thickness. The inner layer 22 of the lower surface portion 15c and the second coil 13 have substantially the same film thickness.

  As shown in FIGS. 1B and 2, a second plating layer 23 as an outer layer is formed on the surface of the inner layer 21 constituting the first upper surface portion 15 b of the first extraction electrode layer 15. Further, a second plating layer 23 as an outer layer is formed on the surface of the inner layer 22 constituting the first lower surface portion 15c of the first extraction electrode layer 15.

  Further, as shown in FIGS. 1B and 2, the first side surface portion 15 a of the first extraction electrode layer 15 is formed by a laminated structure of the first plating layer 19 and the second plating layer 23. The

  In the first side surface portion 15 a of the first extraction electrode layer 15, the first plating layer 19 is formed directly on the first side surface 11 d of the insulating base material 11, and on the surface of the first plating layer 19. The second plating layer 23 is formed so as to overlap.

  Although the laminated structure of the first extraction electrode layer 15 has been described above, the same applies to the second extraction electrode layer 16. That is, as shown in FIG. 1B, the second side surface portion 16a of the second extraction electrode layer 16 has a laminated structure of the first plating layer 19 and the second plating layer 23, and the second The upper surface portion 16b has a laminated structure of the first foil body 18, the first plating layer 19 and the second plating layer 23, and the second lower surface portion 16c has the second foil body 20 and the first This is a laminated structure of one plating layer 19 and second plating layer 23.

As shown in FIG. 1B, the conductive layer 14 is formed of a first plating layer 19.
For example, the first foil bodies 18 and 20 are copper foils, and the first plating layer 19 and the second plating layer 23 are copper plating. Therefore, the inner layers 21 and 22 and the second plating layer 23 which is the outer layer are integrated.

  As shown in FIGS. 1A and 1B and FIG. 2, the first coil 12 and the first extraction electrode layer 15 are a laminate composed of a common first foil body 18 and a first plating layer 19. The second coil 13 and the second extraction electrode layer 16 are integrated with a laminated structure composed of the common second foil body 20 and the first plating layer 19. It has become. The conductive layer 14 is formed of the first plating layer 19 and is formed integrally with the first coil 12 and the second coil 13 including the first plating layer 19.

  Thus, in the present embodiment, the first coil 12, the second coil 13, the first extraction electrode layer 15, the second extraction electrode layer 16, and the conduction layer 14 are integrally formed.

  Thereby, compared with the structure which formed each coil 12 and 13 and each extraction electrode layer 15 and 16 separately like the past, it can aim at reduction of contact resistance. According to the configuration of the present embodiment, the contact resistance between each coil and each extraction electrode layer can be made zero. In this embodiment, the contact resistance between the coils 12 and 13 and the conductive layer 14 can be reduced. Specifically, the contact resistance between each coil and the conductive layer can be made zero.

  In the present embodiment, the first coil 12 and the second coil 13 are formed above and below the insulating base material 11. Thereby, a high inductance can be obtained. Further, since the coils 12 and 13 are formed above and below the insulating base material 11, the extraction electrode layers 15 and 16 can be drawn out from the coils 12 and 13 with a simple structure.

  In the present embodiment, the first extraction electrode layer 15 and the second extraction electrode layer 16 are both provided with upper surface portions 15b and 16b and lower surface portions 15c and 16c. For this reason, it can be electrically connected to the mounting substrate 25 regardless of which of the upper and lower surfaces of the thin inductor 10 faces the mounting substrate 25. That is, as shown in FIG. 2, the first lower surface portion 15c of the first extraction electrode layer 15 and the second lower surface portion 16c of the second extraction electrode layer 16 not shown in FIG. However, even if the thin inductor shown in FIG. 2 is turned 180 degrees, it can be electrically connected to the connection terminal 25a of the mounting board 25. Therefore, the thin inductor 10 can be easily and reliably mounted on the surface of the mounting substrate 25, and good assemblability can be obtained. If such a function is not required, since the second coil 13 is connected to the second extraction electrode 16 and the second lower surface portion 16c, the solder layer 35 described later has first and second side surfaces. Considering the provision between the portions 15a and 16a and the first and second lower surface portions 15c, the second upper surface portion 16b may be omitted.

  Further, as shown in FIGS. 1B and 2, each extraction electrode layer 15 and 16 includes not only the upper surface portions 15b and 16b and the lower surface portions 15c and 16c but also the side surface portions 15a and 16a, and the upper surface portions 15b and 16b. In addition, the structure is integrated with the lower surface portions 15c and 16c to support the insulating base 11 from both sides in the X1-X2 direction. Therefore, each extraction electrode layer 15 and 16 can be made to function as a double-sided support that suppresses deformation of the thin inductor.

  As shown in FIGS. 1B and 2, the first upper surface portion 15 b and the first lower surface portion 15 c constituting the first extraction electrode layer 15, and the second extraction electrode layer 16 constituting the second extraction electrode layer 16. The upper surface portion 16 b and the second lower surface portion 16 c are formed thicker than the first coil 12 and the second coil 13.

  Therefore, there is a step between the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the first extraction electrode layer 15 and the second extraction electrode layer 16, and the first coil 12 and the second coil 13. Can be formed. As shown in FIGS. 1B and 2, the first magnetic sheet 17 is disposed on the upper surface of the first coil 12 via an insulating layer (adhesive layer) 31. Further, as shown in FIGS. 1B and 2, a second magnetic sheet 30 is disposed on the lower surface of the second coil 13 via an insulating layer (adhesive layer) 32. At this time, in this embodiment, as shown in FIGS. 1B and 2, the surfaces of the first magnetic sheet 17, the first upper surface portion 15 b, and the second upper surface portion 16 b are substantially the same surface. Thus, the 1st magnetic sheet 17 can be arrange | positioned. Further, the second magnetic sheet 30 can be arranged so that the surfaces of the second magnetic sheet 30, the first lower surface portion 15c, and the second lower surface portion 16c are substantially the same surface.

  Alternatively, in the present embodiment, each surface of the first upper surface portion 15b and the second upper surface portion 16b is protruded in a direction (upward) away from the insulating base material 11 than the surface of the first magnetic body layer 17. You can also Alternatively, the surfaces of the first lower surface portion 15c and the second lower surface portion 16c may be protruded in a direction (downward) away from the insulating base material 11 relative to the surface of the second magnetic layer 30.

  As described above, each upper surface portion, each lower surface portion, and each magnetic layer are formed on substantially the same surface, or each surface of each upper surface portion, each lower surface portion is outward from each surface of each magnetic layer. By projecting, when the thin inductor 10 is mounted on the mounting board 25 with solder or the like, mounting defects or the like are less likely to occur.

In the present embodiment, the Q value can be improved by using the magnetic sheets 17 and 30, and the magnetic sheets 17 and 30 can be used as a magnetic shield. The configuration of the magnetic sheets 17 and 30 is not particularly limited. A structure in which a magnetic layer of FeAlN or FeN is formed on the surface of an insulating sheet such as polyethylene naphthalate, polyethylene terephthalate or polyamide, and a magnetic layer of FeAlN or FeN and an insulating layer of SiO ₂ or the like alternately on the surface of the insulating sheet A predetermined number of laminated structures, or existing ferrite sheets, ferrite plates, magnetic alloy ribbons, etc. can be presented.

  For the insulating layers (adhesive layers) 31 and 32 that join the coils 12 and 13 and the magnetic sheets 17 and 30, for example, an epoxy-based low-temperature curing agent or an acrylic low-temperature curing agent can be used.

Since the insulating layers 31 and 32 are interposed between the coils 12 and 13 and the magnetic sheets 17 and 30, the magnetic layers of the magnetic sheets 17 and 30 can be bonded toward the coils 12 and 13, respectively. It is also possible to bond the magnetic layers of the sheets 17 and 30 outward. In addition, an insulating film (not shown) is previously formed of SiO ₂ , Al ₂ O ₃ , SiAlON, AlN or the like on the surface of the magnetic layer of each magnetic sheet 17, ₃₀ , and an adhesive is used for the insulating layers 31, 32. A structure in which the magnetic layers of the magnetic sheets 17 and 30 are pressure-bonded and bonded toward the coils 12 and 13 in a state where the adhesive is filled may be employed. With this configuration, the adhesive is crushed by pressure bonding, and the distance between the coils 12 and 13 and the magnetic sheets 17 and 30 is almost the thickness of the insulating film on the surface of the magnetic layer. It is possible to further reduce the thickness of the thin inductor while holding it, and it is also possible to improve the inductance value and the Q value.

  In the configuration shown in FIG. 2, the surfaces of the first magnetic sheet 17, the first upper surface portion 15 b, and the second upper surface portion 16 b are substantially the same surface, and the second magnetic sheet 30, the first magnetic sheet 30, Since each surface of the lower surface portion 15c and the second lower surface portion 16c is substantially the same surface, each upper surface portion 15b, 16b and each lower surface portion 15c, 16c can be configured as a mounting surface for the mounting substrate 25. Good electrical connectivity with the 25 connection terminals 25a can be obtained.

  As shown in FIGS. 1B and 2, in this embodiment, the first upper surface portion 15 b and the first lower surface portion 15 c of the first extraction electrode layer 15 are formed by the inner layers 21 and 22 and the outer layer (second layer). And a plating layer 23). The inner layer 21 is formed with substantially the same film thickness as the coils 12 and 13. The second extraction electrode layer 16 has the same configuration as that of the first extraction electrode layer 15 and will be described below using the first extraction electrode layer 15.

  As shown in FIG. 2, the inner layer 21 and the first coil 12 of the first upper surface portion 15 b have the same laminated structure of the first foil body 18 and the first plating layer 19. The inner layer 21 of the upper surface portion 15b and the first coil 12 can be formed with the same film thickness.

  As shown in FIG. 2, the inner layer 22 and the second coil 13 of the first lower surface portion 15 c have a laminated structure of the same second foil body 20 and the first plating layer 19. The inner layer 21 of the lower surface portion 15c and the second coil 13 can be formed with the same film thickness. The first plating layer 19 is, for example, an electroless plating layer, and thus the first plating layer 19 is applied from the surface of the first foil body 18 and the second foil body 20 to the first side surface 11d of the insulating equipment 11. Can be formed directly.

  Then, the second plating layer 23 is formed so as to overlap the surface of the first plating layer 19 constituting the first upper surface portion 15b and the first lower surface portion 15c, whereby the first upper surface portion 15b. And the film thickness of the 1st lower surface part 15c can be formed thicker than the 1st coil 12 and the 2nd coil 13. FIG.

  The second plating layer 23 is also formed so as to overlap the first plating layer 19 formed on the first side surface 11d, and the first side surface portion 15a is formed with the first plating layer 19 and the second plating layer. 23 and a laminated structure.

  The second plating layer 23 is preferably an electrolytic plating layer. Although the electroless plating layer can be used, the second plating layer 23 can be formed thicker in a shorter time.

  The first plating layer 19 and the second plating layer 23 are preferably formed of the same or the same material and are integrated.

  As an example of the thickness of each layer, the thickness of each foil body 18, 20 is about 35 μm, the thickness of the first plating layer 19 is about 35 μm, and the thickness of the second plating layer 23 is about 65 to 75 μm. It is.

  As shown in FIGS. 1A and 1C, in the present embodiment, the first extraction electrode layer 15 is formed to have the same length as the first side surface 11d of the insulating base material 11. The second extraction electrode layer 16 is formed to have the same length as the second side surface 11e of the insulating substrate 11. As shown in FIG. 1A, the length in the Y1-Y2 direction of the first extraction electrode layer 15, the first side surface 11d, the second extraction electrode layer 16, and the second side surface 11e is L1. .

Further, as shown in FIG. 1A, the first upper surface portion 15b of the first extraction electrode layer 15 and the second upper surface portion 16b of the second extraction electrode layer 16 maintain the length dimension of L1 as X1. It is formed with a width dimension of T1 in the -X2 direction. Further, as shown in FIG. 1C, the first lower surface portion 15c of the first extraction electrode layer 15 and the second lower surface portion 16c of the second extraction electrode layer 16 maintain the length of L1. It is formed with a width dimension of T1 in the X1-X2 direction.
The length dimension L1 is about 2 to 5 mm, and the width dimension T1 is about 0.35 mm.

  Thus, the first extraction electrode layer 15 and the second extraction electrode layer 16 can be formed in a wide area, the contact resistance with the connection terminal 25a of the mounting substrate 25 can be reduced, and each of the extraction electrode layers 15 and 16 can be reduced. The connection terminals 25a can be reliably and easily electrically connected.

  As shown in FIG. 2, in this embodiment, a solder land 34 is formed on the outermost surface of the first extraction electrode layer 15. A solder land is also formed on the outermost surface of the second extraction electrode layer 16. The solder land 34 is, for example, a Ni / Au layer (Ni is the base side), a Ni / Sn layer, a Ni / solder layer, or a Ni / Ag layer. The film thickness of the solder land 34 is as thin as about 5 μm.

  As shown in FIG. 2, the first extraction electrode layer 15 and the connection terminal 25 a of the mounting substrate 25 are joined by a solder layer 35. By providing the solder lands 34 on the outermost surface of the first extraction electrode layer 15, the solder wettability of the outermost surface of the first extraction electrode layer 15 is improved. As shown in FIG. The electrical connectivity between the first extraction electrode layer 15 and the connection terminal 25a of the mounting substrate 25 can be improved. The second extraction electrode layer 16 and the connection terminal 25a of the mounting substrate 25 can also be joined by a fillet-like solder layer.

  As shown in FIG. 1A, the first extending direction α1 from the winding start end 12a of the first coil 12 is the X1 direction (first direction), whereas, as shown in FIG. Furthermore, the first extending direction α2 from the winding start end 13a of the second coil 13 is the X2 direction (second direction), and the extending directions of the first coil 12 and the second coil 13 are opposite to each other. It has become.

  Furthermore, the extending directions α1 and α2 are orthogonal to the length directions (Y1-Y2) of the first side surface 11d and the second side surface 11e of the insulating base material 11. Thereby, the number of turns of the first coil 12 and the second coil 13 can be made the same, the number of turns can be increased to the maximum, and the inductance can be increased.

  3A is another embodiment different from FIGS. 1A and 1C, and the right view of FIG. 3A shows a plan view of the first coil 40, and FIG. The left figure of (a) shows a plan view of the second coil 41.

  As shown in FIG. 3A, the first extending direction α3 from the winding start end 40a of the first coil 40 is the Y1 direction, and the first extending direction α4 from the winding start end 41a of the second coil 41 is Y2 direction.

  As shown in the right diagram of FIG. 3A, the winding end 40b of the first coil 40 is connected to an integrated first extraction electrode layer 42, and the first extraction electrode layer 42 has an insulating group. It is formed along the length direction (X1-X2) of the first side surface (not shown) of the material.

  3A, the winding end 41b of the second coil 41 is connected to the integrated second extraction electrode layer 43, and the second extraction electrode layer 43 is insulated. It forms along the length direction (X1-X2) of the 2nd side surface (not shown) of a base material.

  That is, the first extending directions α3 and α4 (Y1-Y2) from the winding start ends 40a and 41a of the first coil 40 and the second coil 41 are opposite to each other, and the extending direction α3 α4 is orthogonal to the length direction (X1-X2) of the first side surface and the second side surface of the insulating base.

  As a result, as shown in FIG. 3A, the first coil 40 and the second coil 41 have the same number of turns, and when the first coil 40 and the second coil 41 are overlapped, The positions of the respective turns of the coil 40 coincide with the positions of the respective turns of the second coil 41, and the number of turns can be increased to the maximum.

  On the other hand, FIG. 3B shows the coil in the comparative example, the right figure in FIG. 3B shows a plan view of the first coil 45, and the left figure in FIG. A plan view of the coil 46 is shown.

  As shown in FIG. 3B, the first extending direction α5 from the winding start end 45a of the first coil 45 is the Y1 direction, and the first extending direction α6 from the winding start end 46a of the second coil 46 is Y2 direction.

  As shown in the right diagram of FIG. 3B, the winding terminal end 45b of the first coil 45 is connected to the integrated first extraction electrode layer 47, and the first extraction electrode layer 47 has an insulating group. It is formed along the length direction (Y1-Y2) of the side surface (not shown) of the material.

  3B, the winding end 46b of the second coil 46 is connected to the integrated second extraction electrode layer 48, and the second extraction electrode layer 48 is insulated. It is formed along the length direction (Y1-Y2) of the side surface (not shown) of the substrate.

  In the comparative example of FIG. 3B, the first extending directions α5 and α6 (Y1-Y2) from the winding start ends 45a and 46a of the first coil 45 and the second coil 46 are opposite to each other. The extending directions α5 and α6 are parallel to the length direction (Y1-Y2) of the side surface of the insulating base material on which the extraction electrode layers 47 and 48 are formed.

  As a result, as shown in FIG. 3B, the number of turns of the first coil 45 and the second coil 46 is different. As shown in FIG. 3B, the number of coil turns in the Y2 side region as viewed from the winding start end 45a of the first coil 45 is 3, but the Y2 side as viewed from the winding start end 46a of the second coil 46. The number of coil turns in the region is four.

  As described above, in the comparative example of FIG. 3B, the number of turns of the first coil 45 and the second coil 46 do not coincide with each other, and the number of turns cannot be increased to the maximum. The inductance is reduced as compared with the embodiment of (a).

  Thus, as shown in FIG. 3A, the first extending directions α3 and α4 (Y1-Y2) from the winding start ends 40a and 41a of the first coil 40 and the second coil 41 are opposite to each other. And by making the said extending directions (alpha) 3 and (alpha) 4 orthogonal to the length direction (X1-X2) of the 1st side surface and 2nd side surface of an insulating base material, an increase in inductance can be aimed at. . In addition, in order to obtain the same number of turns, a thin inductor with a minimum size including the extraction electrode layer can be obtained.

  In addition, the common characteristic part of this embodiment is the point which integrated the coil, the conduction | electrical_connection layer, and the extraction electrode layer. Therefore, the relationship between the coil winding direction and the extraction electrode layer extension direction does not exclude the configuration of FIG. However, FIG. 3A is preferable.

  FIG. 4 is a longitudinal sectional view of a thin inductor according to another embodiment. In FIG. 4, the same reference numerals are assigned to the same layers as in FIG.

  In FIG. 4, unlike FIG. 1B, the second plating layer 23 is not formed on the first extraction electrode layer 15 and the second extraction electrode layer 16. Therefore, in FIG. 4, the upper surface portions 15 b and 16 b and the lower surface portions 15 c and 16 c of the first extraction electrode layer 15 and the second extraction electrode layer 16 are similar to the first coil 12 and the second coil 13. It is a laminated structure of the foil bodies 18 and 20 and the first plating layer 19 and has substantially the same film thickness. Therefore, as shown in FIG. 4, there is a step between the surface of the magnetic sheets 17 and 30 and the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the extraction electrode layers 15 and 16, respectively. Therefore, as illustrated in FIG. 3, the gap β is easily formed between the lower surface portions 15 c and 16 c of the extraction electrode layers 15 and 16 and the connection terminals 25 a of the mounting substrate 25. The gap β is filled with the solder layer 35, and the lead electrode layers 15, 16 and the connection terminal 25 a are electrically connected via the solder layer 35.

  However, in the case of the configuration of FIG. 3, the lower surface portions 15c and 16c of the extraction electrode layers 15 and 16 are not mounted on the mounting substrate 25 and are in a floating state, so that the contact resistance with the connection terminal 25a is reduced. In order to obtain a reliable connection with the connection terminal 25a, as shown in FIG. 1B and FIG. 2, a second plating layer is formed on the first extraction electrode layer 15 and the second extraction electrode layer 16. 23, and the film thicknesses of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the extraction electrode layers 15 and 16 are made larger than the film thickness of the coils 12 and 13, respectively. It is preferable that the surface of 30 and the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the extraction electrode layers 15 and 16 are substantially coplanar. Alternatively, it is preferable to have a structure in which the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c protrude in a direction away from the insulating base material 11 than the surfaces of the magnetic sheets 17 and 30.

  Next, the manufacturing method of the thin inductor (magnetic element) in this embodiment is demonstrated. Each drawing in FIG. 5 is a partial longitudinal sectional view of the thin inductor in the manufacturing stage. In addition, the same code | symbol was attached | subjected about the same layer as FIG.

  In FIG. 5A, an insulating substrate 51 is prepared in which the first foil body 18 is formed on the upper surface 11a of the insulating base material 11, and the second foil body 20 is formed on the lower surface 50b. The insulating substrate 51 is processed as shown in FIGS. 5B to 5F and cut in the step of FIG. 5F to obtain a plurality of thin inductors shown in FIG. 1 from the insulating substrate 51. Is possible. For example, the insulating substrate 51 is preferably a glass epoxy substrate having copper foil on the upper and lower surfaces. Here, the film thicknesses of the first foil body 18 and the second foil body 20 are, for example, about 35 μm.

  In the step of FIG. 5B, the through holes 52 are formed at positions between the regions when the insulating substrate 51 is divided into a plurality of thin inductor regions. The through hole 52 is formed from the upper surface 51 a to the lower surface 51 b of the insulating substrate 51. The length dimension of the through hole 52 in the Y1-Y2 direction is L1 shown in FIG. In addition, the width dimension T3 of the through hole 52 in the X1-X2 direction is preferably equal to or larger than the width dimension T5 of the through hole 53, and is preferably as small as possible so that a large number of thin inductors can be removed from the insulating substrate 51. In particular, the width dimension T3 is a film thickness T4 obtained by adding the thicknesses of the first plating layer 19 and the second plating layer 23 formed on the side surfaces 11d and 11e of each thin inductor (FIGS. 1A and 1B). It is formed to be larger than twice of (see). Specifically, the width dimension T3 is set to 200 μm or more.

  Further, as shown in FIG. 5B, a through hole 53 penetrating from the upper surface 51a to the lower surface 51b of the insulating substrate 51 is formed at a substantially central position of the region to be each thin inductor. The through hole 53 has, for example, a cylindrical shape or a prismatic shape. As shown in FIG. 1B, the width dimension T <b> 3 of the through hole 52 is formed larger than the width dimension T <b> 5 of the through hole 53.

  The through hole 52 and the through hole 53 can be formed using a photolithography technique. Alternatively, the hole can be formed at low cost not only by photolithography but also by machining such as a drill.

  Next, in the step of FIG. 5C, the first plating layer 19 is formed by electroless plating over the first foil body 18 and the second foil body 20. At this time, the conductive layer 14 made of the first plating layer 19 is formed in the through hole 53, and the side wall surfaces 52 a and 52 b in the through hole 52 from the surface of the first foil body 18 and the second foil body 20. The first plating layer 19 is formed over the surface. The first plating layer 19 is formed by electroless plating with Cu, for example. The film thickness of the 1st plating layer 19 shall be about 35 micrometers, for example.

  Subsequently, in the step of FIG. 5D, the first coil 12 including the first foil body 18 and the first plating layer 19 is formed on the upper surface side of each region to be a thin inductor by using a photolithography technique. Further, the second coil 13 including the second foil body 20 and the first plating layer 19 is formed on the lower surface side of each region to be a thin inductor.

  For example, the 1st coil 12 and the 2nd coil 13 are formed in the plane shape shown in Drawing 1 (a) and Drawing 1 (c).

  As shown in FIG. 5 (d), the winding start end 12a located inside the first coil 12 and the conductive layer 14 are formed integrally, and the winding start end 13a located inside the second coil 13; The conductive layer 14 is integrally formed.

  5D, the first extraction electrode layer 15 connected to the winding end 12b located outside the first coil 12, and the winding termination 13b located outside the second coil 13. A second extraction electrode layer 16 to be connected is formed (see also FIGS. 1A and 1C).

  The first side wall surface 52 a of the through hole 52 corresponds to the first side surface 11 d of the insulating base material 11 constituting the thin inductor 10. Further, the second side wall surface 52 b of the through hole 52 corresponds to the second side surface 11 e of the insulating base material 11 constituting the thin inductor 10. And the 1st extraction electrode layer 15 has the 1st side part 15a which has the 1st plating layer 19 by the electroless plating directly formed in the 1st side wall surface 52a, and the insulating base material from the 1st side part 15a. 11 includes a first upper surface portion 15b extending to the upper surface of the insulating member 11, and a first lower surface portion 15c extending from the first side surface portion 15a to the lower surface of the insulating base material 11. The second extraction electrode layer 16 includes a second side surface portion 16a having a first plating layer 19 by electroless plating directly formed on the second side wall surface 52b, and an insulating base material from the second side surface portion 16a. 11 has a second upper surface portion 16 b extending to the upper surface of the insulating member 11 and a second lower surface portion 16 c extending from the second side surface portion 16 a to the lower surface of the insulating base material 11.

  As shown in FIGS. 1A and 1C, the first extraction electrode layer 15 and the second extraction electrode layer 16 are formed with a length dimension L1 in the Y1-Y2 direction. The length dimension L1 matches the length dimension in the Y1-Y2 direction of the first side surface 11d and the second side surface 11e of the insulating base material 11 constituting each thin inductor 10.

  As shown in FIG. 5D and FIG. 1A, the first coil 12 and the first extraction electrode layer 15 have a laminated structure of the same first foil body 18 and first plating layer 19. The first coil 12 is integrally formed from the winding end 12 b of the first coil 12 to the first upper surface portion 15 b of the first extraction electrode layer 15. Further, as shown in FIGS. 5D and 1C, the second coil 13 and the second extraction electrode layer 16 are laminated structures of the same second foil body 20 and the first plating layer 19. The second coil 13 is integrally formed from the winding end 13b of the second coil 13 to the second lower surface portion 16c of the second extraction electrode layer 16.

  Next, in the step of FIG. 5E, the second plating layer 23 is formed on the surfaces of the first plating layer 19 of the first extraction electrode layer 15 and the second extraction electrode layer 16 by electrolytic plating. The second plating layer 23 is preferably formed of the same or the same material as the first plating layer 19. For example, the second plating layer 23 is formed of Cu. Moreover, the film thickness of the 2nd plating layer 23 shall be about 65-75 micrometers, for example.

  In order to form the second plating layer 23 only on the first extraction electrode layer 15 and the second extraction electrode layer 16, a resist layer is formed in a region other than the first extraction electrode layer 15 and the second extraction electrode layer 16. Is provided so that the second plating layer 23 is not plated.

  Thereby, the film thickness of each upper surface part 15b, 16b and each lower surface part 15c, 16c of the 1st extraction electrode layer 15 and the 2nd extraction electrode layer 16 is set rather than the 1st coil 12 and the 2nd coil 13. It can be formed thick.

  At this time, the side portions 15 a and 16 a of the first extraction electrode layer 15 and the second extraction electrode layer 16 are formed in a laminated structure of the first plating layer 19 and the second plating layer 23. At this time, as shown in FIG. 5E, the first extraction electrode layer 15 and the second extraction electrode layer 16 adjacent in the through hole 52 are not in contact with each other, and the space is open.

  The first plating layer 19 and the second plating layer 23 are formed of the same or the same material, and the first plating layer 19 and the second plating layer 23 are integrated.

  Furthermore, the solder which consists of Ni / Au layer (Ni is a base side), Ni / Sn layer, Ni / solder layer, Ni / Ag layer etc. on the outermost surface of the 1st extraction electrode layer 15 and the 2nd extraction electrode layer 16 A land 34 is formed (see FIG. 2).

  Next, in the process of FIG. 5F, insulating layers 31 and 32 are formed on the surfaces of the first coil 12 and the second coil 13. An epoxy low temperature curing agent or an acrylic low temperature curing agent can be used for the insulating layers 31 and 32. Then, the magnetic sheets 17 and 30 are attached to the surfaces of the insulating layers 31 and 32. At this time, the surfaces of the magnetic sheets 17 and 30 and the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the first extraction electrode layer 15 and the second extraction electrode layer 16 are formed in substantially the same plane. Can do. Further, the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c of the first extraction electrode layer 15 and the second extraction electrode layer 16 are further away from the insulating base material 11 than the surfaces of the magnetic sheets 17 and 30. A structure that protrudes in the direction can also be used. In this way, at least the magnetic sheets 17 and 30 may be configured not to protrude from the surfaces of the upper surface portions 15b and 16b and the lower surface portions 15c and 16c so that there is no problem when the circuit board is mounted with solder.

  When the insulating substrate 51 is cut from the position of the one-dot chain line in FIG. 5F, a plurality of thin inductors 10 can be obtained.

  According to the method for manufacturing the thin inductor 10 of the present embodiment shown in FIG. 5, as shown in FIGS. 5B to 5D, the coils 12 and 13, the conductive layer 14, and the extraction electrode layer 15, 16 can be formed in the same process, and the coils 12 and 13, the conductive layer 14, and the extraction electrode layers 15 and 16 can be integrally formed. Therefore, in the present embodiment, a thin inductor capable of reducing the contact resistance between the coils 12 and 13 and the extraction electrode layers 15 and 16 and between the coils 12 and 13 and the conductive layer 14 is superior in manufacturing efficiency compared to the conventional case. Can be manufactured.

  5E, the second plating layer 23 can be formed on the first plating layer 19 in the first extraction electrode layer 15 and the second extraction electrode layer 16 so as to overlap with each other. The first upper surface portion 15 b and the first lower surface portion 15 c of the extraction electrode layer 15 and the second upper surface portion 16 b and the second lower surface portion 16 c of the second extraction electrode layer 16 are thicker than the coils 12 and 13. Can be formed. For this reason, in the step of FIG. 5 (f), magnetic sheets 17 and 30 that are substantially flush with the surfaces of the first extraction electrode layer 15 and the second extraction electrode layer 16 are appropriately applied to the surfaces of the coils 12 and 13, respectively. It can be installed easily. Alternatively, the surface of the first extraction electrode layer 15 and the second extraction electrode layer 16 may be configured to protrude from the surfaces of the magnetic sheets 17 and 30.

  Further, in order to manufacture a thin inductor having the structure shown in FIG. 4, the step shown in FIG.

  In the present embodiment, the second upper surface portion 16b that constitutes the second extraction electrode layer 16 may not be formed. By providing a resist or the like at the position of the second upper surface portion 16b so that the plating layer is not formed, a thin inductor having a configuration without the second upper surface portion 16b can be formed.

DESCRIPTION OF SYMBOLS 10 Thin inductor 11 Insulation base material 11c, 53 Through hole 12, 40, 45 1st coil 12a, 13a, 40a, 41a, 45a, 46a Winding start end 12b, 13b, 40b, 41b, 45b, 46b Winding end 13,41 , 46 Second coil 14 Conductive layers 15, 42, 47 First extraction electrode layer 15a First side surface portion 15b First upper surface portion 15c First lower surface portions 16, 43, 48 Second extraction electrode layer 16a Second side surface portion 16b Second upper surface portion 16c Second lower surface portion 17, 30 Magnetic sheet 18 First foil body 19 First plating layer 23 Second plating layer 25 Mounting substrate 31, 32 Insulating layer 34 Solder Land 35 Solder layer 51 Insulating substrate 52 Through hole

Claims (5)

Preparing an insulating substrate capable of being cut into a plurality of magnetic elements, wherein the first foil body is formed on the upper surface of the insulating base and the second foil body is formed on the lower surface;
A first step of forming a through hole in a position between regions to be each magnetic element of the insulating substrate and forming a through hole in a region to be each magnetic element;
A first plating layer is formed on the first foil body and the second foil body. At this time, a conductive layer is formed by the first plating layer in the through hole, and the first plating body is formed. A second step of forming the first plating layer from the surface of the first foil body to the side wall surface in the through hole and the surface of the second foil body;
Using a photolithography technique, a first coil including the first foil body and the first plating layer is formed on the upper surface side of the insulating base material, and further, the lower surface of the insulating base material is formed. Forming a second coil having the second foil body and the first plating layer on the side;
At this time, the winding start end located inside the first coil and the inside of the second coil and the conductive layer are integrally formed,
Furthermore, a first side surface portion formed on the first side wall surface of the through hole corresponding to the first side surface of the insulating base material, and extending from the first side surface portion to the upper surface of the insulating base material A first upper surface portion integrated with a winding end located outside the first coil, and a first lower surface portion extending from the first side surface portion to the lower surface of the insulating substrate. A second side surface portion formed on a second side wall surface of the through-hole corresponding to a second side surface different from the first side surface of the insulating base, A second extraction electrode layer is formed which extends from the second side surface portion to the lower surface of the insulating substrate and has a second lower surface portion integrated with a winding terminal located outside the second coil. 3 steps,
A fourth step of obtaining a plurality of the magnetic elements by cutting the insulating substrate;
A method of manufacturing a magnetic element that have a,
Between the third step and the fourth step,
A fifth step of forming a second plating layer made of the same material as the first plating layer on the surface of the first plating layer of the first extraction electrode layer and the second extraction electrode layer,
Have
After the fifth step, a sixth step is provided in which a first magnetic layer is provided on the upper surface side of the first coil and a second magnetic layer is provided on the lower surface side of the second coil. And each surface of the first magnetic layer and the first upper surface portion are substantially flush with each other, or the surface of the first upper surface portion is more insulated than the surface of the first magnetic layer. It protrudes in the direction away from the base material, and the surfaces of the second magnetic layer, the first lower surface portion, and the second lower surface portion are substantially the same surface, or the first lower surface portion and the second lower surface portion. A method of manufacturing a magnetic element, wherein each surface of the lower surface portion of the magnetic material is protruded in a direction away from the insulating base material than the surface of the second magnetic layer. The method of manufacturing a magnetic element according to claim 1 , wherein solder lands are formed on the outermost surfaces of the first extraction electrode layer and the second extraction electrode layer. The second extraction electrode layer has the same structure as the first upper surface portion, extending from the second side surface portion to the upper surface of the insulating base material, together with the second side surface portion and the second lower surface portion. The method for manufacturing a magnetic element according to claim 1 , wherein the second upper surface portion is formed.   The magnetic element manufacturing method according to any one of claims 1 to 3, wherein the first foil body, the second foil body, the first plating layer, and the second plating layer are all made of Cu. Method.   5. The method of manufacturing a magnetic element according to claim 1, wherein the first plating layer is formed by an electroless plating method, and the second plating layer is formed by an electrolytic plating method.

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