JP2003059722A - Laminated inductor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated inductor that has a high degree of freedom for design of magnetic path configuration and a small size, and to provide a method of manufacturing the inductor. SOLUTION: Conductor patterns 13a-13g and 14a-14f for coil are respectively exposed on the top and bottom faces of a laminate 16 and columnar connecting conductors 15A are respectively exposed on both side faces of the laminate 16. The top, bottom, and both side faces of the laminate 16 are covered with an insulating protective film 17 by leaving both end faces of the laminate 16 uncovered. A resin, ceramic paste, etc., is used for forming the protective film 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor, in particular, a laminated inductor used as an EMI filter and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a laminated inductor of this type, a laminated inductor 1 shown in FIG. 32 is conventionally known. This laminated inductor 1 is provided with an insulating sheet 2a having coil conductor patterns 3a to 3d on its surface, an insulating sheet 2d having coil conductor patterns 4a to 4d on its surface, and a plurality of through holes 5. Insulator sheet 2
b, 2c, etc. are stacked and integrally fired to form a laminated body.

Coil conductor pattern 3a on top of the laminate
˜3d and lower coil conductor patterns 4a to 4d are respectively arranged in the same layer, and both are electrically connected in series through a plurality of through holes 5 arranged in the insulating sheets 2a to 2c. To form a spiral coil L. The axial direction of the spiral coil L is perpendicular to the stacking direction of the insulator sheets 2a to 2d, and also perpendicular to the input / output external electrodes 7 and 8 (see FIG. 33). In other words, the axial direction of the spiral coil L is parallel to the mounting surface of the laminated inductor 1.

[0004]

By the way, as electronic equipment typified by a mobile phone terminal has become higher in performance and smaller in size in recent years, the laminated inductor 1 is also required to have improved electric characteristics and smaller size. Therefore, in order to satisfy these requirements, a design has been attempted in which the insulating region secured between the spiral coil L built in the inductor 1 and the outer surface of the inductor 1 is made small. Here, a particular problem is to design in consideration of processing accuracy so that the through hole 5 is not exposed to the outer surface of the inductor 1 during processing. However, there is a limit to the reduction of the insulating area due to the restriction of processing accuracy.

Further, when a magnetic material such as ferrite is used as the material of the insulating sheets 2a to 2d, FIG.
, The magnetic flux φ generated by the spiral coil L
Passes through the inductor 1. That is, the inductor 1 constitutes a closed magnetic circuit. Therefore, this inductor 1
When changing the configuration to the open magnetic circuit configuration, the insulating sheet 2a to
It is necessary to use a dielectric material or an insulating material as the material of 2d. As described above, the magnetic path configuration of the conventional multilayer inductor 1 is usually changed by selecting the material of the insulating sheets 2a to 2d.
There was also the problem that the degree of freedom in the design of the magnetic path configuration was low.

Therefore, an object of the present invention is to provide a small laminated inductor having a high degree of freedom in designing the magnetic path structure and a method for manufacturing the same.

[0007]

In order to achieve the above object, a laminated inductor according to the present invention comprises: (a) a laminated body constituted by stacking a plurality of insulating layers; and (b) the laminated body. A plurality of coil conductor patterns arranged on an upper part of the laminated body, (c) a plurality of coil conductor patterns arranged on a lower part of the laminated body, and (d) respectively arranged on both side portions of the laminated body, and A plurality of columnar connecting conductors, at least one of which is exposed on both side surfaces of the laminate,
(E) a conductor pattern for a coil and / or an insulating protective film for covering a columnar connecting conductor exposed on the surface of the laminate, and (f) the conductor pattern for a coil in the upper and lower portions is in the columnar shape. A coil configured by alternately electrically connecting in series via connection conductors has a coil axis in a direction perpendicular to a stacking direction of the insulator layers.

With the above structure, the insulating protective film covers the conductor pattern for coil and / or the columnar connecting conductor exposed on the surface of the laminated body, so that highly precise processing is not required.

Further, by exposing all of the columnar connecting conductors on both side surfaces of the laminate, an open magnetic circuit structure can be obtained even when the material of the insulating layer is a magnetic material. Therefore, the direct current superposition characteristic of the inductance is improved.

Further, a plurality of columnar connecting conductors are respectively arranged near both side portions of the laminated body to form magnetic paths between the coil and both side surfaces of the laminated body, and the columnar connecting conductors are formed on both side surfaces of the laminated body. It is characterized in that at least one of the connection conductors extends in the radial direction of the coil over the entire length of the columnar connection conductor to cross the magnetic path and is exposed on both side surfaces of the laminated body. As a result, a non-magnetic portion is provided in the magnetic path, an open magnetic circuit structure close to a closed magnetic path is obtained, and excellent DC superposition characteristics are obtained, and a large inductance is also obtained. Thus, the non-closed magnetic circuit structure includes an open magnetic circuit structure and an open magnetic circuit structure close to the closed magnetic circuit.

Further, in the multilayer inductor according to the present invention, all of the plurality of columnar connecting conductors are exposed on both side surfaces of the laminated body, and a part of the plurality of columnar connecting conductors is folded back into the coil, so that the folded portion A magnetic path is formed between the coil and both side surfaces of the laminated body. As a result, the DC superposition characteristic changes in two steps.

Further, in the method of manufacturing a laminated inductor according to the present invention, (g) an insulating mother sheet having through holes and an insulating mother sheet having a plurality of coil conductor patterns are stacked and integrated. Baking the mother laminate to form a long through hole by connecting the through holes to each other, and (h) cutting the mother laminate at the position of the long through hole. A chip-shaped laminated body of a predetermined size is cut out, and through the columnar connecting conductor formed by dividing the long through-hole into two, conductor patterns for coils respectively arranged on the upper part and the lower part of the chip-shaped laminated body are formed. Alternately connecting electrically in series, to form a coil having a coil axis in a direction perpendicular to the stacking direction of the insulator sheets,
(I) a step of forming an insulating protective film for covering the coil conductor pattern and / or the columnar connecting conductor exposed on the surface of the chip-shaped laminated body. By the above method, the long through hole can be divided into two to efficiently form the columnar connecting conductor.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a laminated inductor and a method of manufacturing the same according to the present invention will be described below with reference to the accompanying drawings.

[First Embodiment, FIGS. 1 to 10] As shown in FIG. 1, a laminated inductor 11 includes an insulating sheet 12a having linear conductor patterns 13a to 13g for a coil provided on an upper surface thereof, and a straight line. -Shaped coil conductor patterns 14a to 1
Insulator sheet 12e having 4f on its lower surface and insulator sheet 12b having a plurality of semi-circular through holes 15 at its edge
.About.12d.

Coil conductor patterns 13a to 13g, 1
4a to 14f are formed by a method such as screen printing, sputtering, vapor deposition, or photolithography. Coil conductor patterns 13a to 13g, 14a to 1
The material of 4f is Ag, Ag-Pd, Pd, Cu,
Ni or the like is used. As the material for the insulating sheets 12a to 12e, a magnetic material such as ferrite, a dielectric material such as ceramics, an insulating material such as glass, and the like are kneaded together with a binder or the like and molded into a sheet shape. .

The through hole 15 is formed by the insulating sheet 12a.
The through holes are formed in the through holes 12e by laser processing or punching, and then the through holes are filled with a conductive paste.
These through holes 15 serve as insulator sheets 12a-1.
The columnar connecting conductors 15A (see FIG. 2) are connected to each other in the stacking direction of 2e.

The conductor patterns 13a to 13g for the coil are
It is arranged on the upper surface of a laminated body 16 (see FIG. 2) described later. The coil conductor patterns 14 a to 14 f are arranged on the lower surface of the laminated body 16. The coil conductor patterns 13a to 13g arranged on the upper surface are respectively insulator sheets 12a to 1g.
The spiral-shaped coil L is formed by electrically connecting in series to the coil conductor patterns 14a to 14f sequentially arranged on the lower surface via the columnar connecting conductor 15A formed of the through hole 15 provided at the edge of 2e. The axial direction of the spiral coil L is perpendicular to the stacking direction of the insulating sheets 12a to 12e, and is also perpendicular to the input / output electrodes 18 and 19 (see FIG. 4) described later. In other words, the axial direction of the spiral coil L is parallel to the mounting surface of the inductor 11.

The above-mentioned insulator sheets 12a to 12e are stacked and then integrally fired, and as shown in FIG.
The laminated body 16 is formed. On the upper surface and the lower surface of the laminated body 16, the coil conductor patterns 13a to 13g and 14a to
14f is exposed, and the columnar connecting conductors 15A are all exposed on both side surfaces of the multilayer body 16.

Next, as shown in FIG. 3, the upper surface, the lower surface and both side surfaces of the laminate 16 are covered with an insulating protective film 17 having a thickness of about 1 to 5 μm, leaving both end surfaces. As a material for the insulating protective film 17, resin, ceramic paste, or the like is used. In the case of a resin, a polymer resin such as epoxy or polyimide is applied to the exposed surface of the coil conductor patterns 13a to 13g by a method such as coating, dipping, printing, spraying or the like, and cured at an appropriate temperature. For example, when formed by the dipping method, the thickness of the insulating protective film 17 is about 50 to 100 μm. Also in the case of the ceramic paste, a ceramic paste such as glass is applied to the exposed surfaces of the coil conductor patterns 13a to 13g and the like by the same method and fired.

The insulating protective film 17 may be formed so as to cover the entire surface of the laminated body 16. However, in this case, it is necessary to chamfer the corner portions on both end surfaces of the laminated body 16 to expose the end portions of the coil conductor patterns 13a and 13g. The corners may be chamfered by mechanical cutting, but if barrel polishing is used, the laminated body 1
Since the chamfering of the corner portion other than both end surfaces of 6 can be performed at the same time, the manufacturing cost is reduced.

Next, as shown in FIG. 4, input / output external electrodes 18 and 19 are provided at both ends of the laminated body 16, respectively. The input / output external electrodes 18 and 19 are electrically connected to the coil conductor patterns 13a and 13g, respectively. These input / output external electrodes 18, 19 are Ag, Ag
It is formed by applying a conductive paste such as -Pd or Cu, baking, and further dry plating. When the insulating protection film 17 is made of resin, the input / output external electrode 1
As the conductive paste of Nos. 8 and 19, one that can be hardened at a low temperature is used. For example, a thermosetting conductive adhesive or the like is used.

FIG. 5 schematically shows the internal structure of the laminated inductor 11. Insulator sheets 12a-1
Even when 2e is made of a magnetic material such as ferrite, the magnetic flux φ generated by the spiral coil L is
Since it passes outside 1, the open magnetic path can be formed. As a result, as shown by the solid line 21 in FIG. 6, the DC superposition characteristic of the inductance of the multilayer inductor 11 is improved.
For comparison, FIG. 6 shows the DC superimposition characteristics of the conventional laminated inductor 1 having a closed magnetic circuit structure in which the insulating sheets 2a to 2d shown in FIG. 32 are made of a magnetic material such as ferrite.
It is also described (see the dotted line 22).

When the insulating sheets 12a to 12e are made of a non-magnetic material, the laminated inductor 11 is an air-core coil, and the spiral coil L has a large inner diameter and has a high inductance and a high Q characteristic. (See solid line 23 in FIG. 7). For comparison, FIG. 7 also shows the Q characteristics of the conventional laminated inductor 1 in which the insulating sheets 2a to 2d shown in FIG. 32 are made of a non-magnetic material (see the dotted line 24). .

Next, the laminated inductor 1 of the first embodiment
A case where 1 is mass-produced using a mother substrate will be described.

As shown in FIG. 8, the laminated inductor 11
Wide area insulator mother sheet 12
A is prepared, and the arrangement positions of the inductors 11 are determined vertically and horizontally. The inductors 11 are arranged so as to be adjacent to each other, and through holes are formed in the boundary portion thereof. In accordance with this position, the coil conductor patterns 13a to 13g are formed by a method such as screen printing, and the through holes are filled with a conductive paste to form the through holes 25.

Similarly, as shown in FIGS. 9 and 10, wide area insulating mother sheets 12B, 12C, 12D, 1 are used.
Prepare 2E. Each of the insulating mother sheets 12B to 12D is provided with through-hole holes corresponding to the number of arrayed inductors 11. Further, the through-hole holes are filled with a conductive paste to form through holes 25.
The through hole 25 is located at the boundary between the adjacent inductors 11. The insulating mother sheet 12E has coil conductor patterns 14a to 14f formed on the lower surface thereof for the number of the inductors 11 arranged. 8 to 10, the coil conductor patterns 13a to 13g and the through holes 25 are omitted except for the four central inductors.

Next, the insulating mother sheets 12E, 12D, 12C, 12B and 12A thus processed are stacked in this order and pressed to form a mother laminated body. The through holes 25 are connected to form a long through hole 25. This mother laminated body is vertically and horizontally cut with a dicer, a laser beam, or a jet water stream, and cut out into each size surrounded by a dashed line in FIGS.
That is, the laminated body 16 as shown in FIG. 2 is obtained. At this time, the long through-hole 25 is divided into two parts, and becomes a columnar connecting conductor 15A having a semicircular cross section. Chip-shaped stack 1
6 is heated to a predetermined temperature and fired. Thereafter, as described above, the upper surface, the lower surface and both side surfaces are covered with the insulating protective film 17 while leaving both end surfaces of the laminated body 16 (see FIG. 3).
Next, as shown in FIG. 4, input / output external electrodes 18 and 19 are provided on both ends of the laminated body 16, respectively.

According to the above method, the laminated inductor 11 can be mass-produced at one time, and can be efficiently manufactured at low cost. In addition, after firing the mother laminated body and forming an insulating protective film on the upper and lower surfaces thereof with a resin or the like, the mother laminated body is cut out into each size surrounded by a dashed line in FIGS. 8 to 10 to obtain a chip-shaped laminated body 16. You may The cross-section (before division) of the elongated through hole 25 may be elliptical, rectangular, square, or the like. A rectangular shape such as a rectangle or a square is preferable in terms of characteristics because it has a large surface area. Furthermore, when the conductive paste is filled in the through holes 25, the paste is unlikely to drop (drop out).

[Second Embodiment, FIGS. 11 to 19] A second embodiment will explain a laminated inductor which has a good DC superimposition characteristic and a large inductance.
As shown in FIG. 11, the laminated inductor 31 includes a plurality of insulating sheets 32a having coil conductive patterns 34a to 34g provided on the upper surface thereof and an insulating sheet 32e having coil conductive patterns 35a to 35f provided on the lower surface thereof. Insulator sheets 32b to 32 provided with through holes 36 and 37 of
d and the protective sheet 33 and the like. The insulating sheets 32a to 32e are made of a magnetic material such as ferrite, a dielectric material such as ceramic, or an insulating material. The protective sheet 33 is made of a glass-based nonmagnetic ceramic sheet or the like.

The through holes 36 and 37 are connected in the stacking direction of the insulating sheets 32a to 32e to form columnar connecting conductors 36A and 37A (see FIG. 12), respectively.
The through hole 37 has an elongated hole shape that reaches the front side or the back side of the insulator sheets 32a to 32e, respectively.

The coil conductor patterns 34a to 34g are
It is arranged on an upper portion of a laminated body 38 (see FIG. 12) described later.
The coil conductor patterns 35 a to 35 f are arranged below the stacked body 38. The conductor patterns 34a to 34g for the coils arranged on the upper part respectively correspond to the insulator sheets 32a to 32a.
The spiral coil L is electrically connected in series to the coil conductor patterns 35a to 35f sequentially arranged at the lower portion via the columnar connecting conductors 36A and 37A formed of the through holes 36 and 37 provided at the edge of 32e. Constitute. The axial direction of the spiral coil L is perpendicular to the stacking direction of the insulating sheets 32a to 32e.

The above sheets 32a to 32e and 33 are stacked and then integrally fired to form a laminated body 38 as shown in FIG. The columnar connecting conductors 37A are exposed on both side surfaces of the laminated body 38, and the end portions of the coil conductor patterns 34a, 34g are exposed on both end surfaces of the laminated body 38, respectively.

Next, as shown in FIG. 13, both side surfaces of the laminated body 38 are covered with insulating protective films 39 and 40, respectively. Resin, ceramic paste, or the like is used as the material of the insulating protective films 39 and 40.

Next, as shown in FIG. 14, input / output external electrodes 41 and 42 are provided at both ends of the laminated body 38, respectively. The input / output external electrodes 41 and 42 are electrically connected to the coil conductor patterns 34a and 34g, respectively.

FIG. 15 schematically shows the internal structure of the laminated inductor 31. Insulator sheet 32a-
When 32e is made of a magnetic material such as ferrite, magnetic paths are formed between the spiral coil L and both side surfaces of the laminated body 38, respectively. Therefore, the magnetic flux φ generated by the spiral coil L passes through the inside of the inductor 11. However, the columnar connecting conductor 37A extends in the radial direction of the spiral coil L over the entire length thereof and crosses the magnetic path. Therefore, due to the columnar connecting conductor 37A made of a non-magnetic material provided in a part of the magnetic path, the inductor 31 does not have a complete closed magnetic path, but has a structure close to the closed magnetic path.

As a result, the inductor 31 can have a large inductance. Further, since a gap of the non-magnetic portion is provided in the magnetic path, magnetic flux leakage occurs in this non-magnetic portion and the magnetic resistance increases. This allows
As shown by the solid line 44 in FIG. 16, the laminated inductor 31
It is possible to improve the DC superimposition characteristic of the inductance. For comparison, FIG. 16 also shows the DC superimposition characteristics of the conventional laminated inductor 1 having a closed magnetic circuit configuration in which the insulating sheets 2a to 2d shown in FIG. 32 are made of a magnetic material such as ferrite. (See dotted line 45). In addition,
The number of columnar connecting conductors 37A forming the non-magnetic portion does not have to be one and may be plural. Further, the non-magnetic portion of the magnetic path may be formed as a cavity or filled with another non-magnetic material.

Next, the laminated inductor 3 of the second embodiment
A case where 1 is mass-produced using a mother substrate will be described.

As shown in FIG. 17, the laminated inductor 3
Wide area insulator mother sheet 3 that can take multiple 1
2A is prepared, and the arrangement position of the inductors 31 is determined vertically and horizontally. The inductors 31 are arranged so as to be adjacent to each other, and a shared through-hole hole is formed only at one place at the boundary portion thereof, and further, an individual through-hole hole is formed for each inductor 31. In accordance with this position, the coil conductor patterns 34a to 34g are formed by a method such as screen printing, and the through holes are filled with a conductive paste to form the through holes 46 and 47. The through hole 47 has a long hole shape.

Similarly, as shown in FIG. 18 and FIG.
Wide area insulator mother sheets 32B, 32C, 32D,
Prepare 32E. Insulator mother sheet 32B-32D
Through holes are formed in each of the inductors by the number corresponding to the number of arrayed inductors 31, and the through holes are filled with a conductive paste to form through holes 46 and 47. The insulating mother sheet 32E has coil lower surface conductive patterns 35a to 35E on the lower surface thereof.
35f is formed.

Next, the insulating mother sheets 32E, 32D, 32C, 32B and 32A processed in this manner are stacked in this order, and further, protective mother sheets having a large area are arranged on the top and bottom, and then pressure is applied to the mother laminated body. To form. The through holes 46 and 47 are connected to each other to form the long through hole 4.
6,47. This mother laminated body is cut vertically and horizontally by a dicer, a laser beam, or a jet water stream, and
~ A chip-shaped laminated body cut out for each size surrounded by the one-dot chain line in Fig. 19, that is, the laminated body 3 as shown in Fig. 12.
Get 8. At this time, the long through-hole 47 is divided into two, and becomes the columnar connecting conductor 37A. The elongated through hole 46 becomes the columnar connecting conductor 36A as it is. The chip-shaped laminated body 38 is heated to a predetermined temperature and fired. Thereafter, as described above, both side surfaces of the laminated body 38 are covered with the insulating protective films 39 and 40 (see FIG. 13). Next, FIG.
As shown in FIG. 3, input / output external electrodes 41 and 42 are provided on both ends of the laminated body 38, respectively.

According to the above method, it is possible to mass-produce once, and it is possible to efficiently obtain the laminated inductor 31 at low cost.

[Third Embodiment, FIGS. 20 to 31] FIG.
As shown in FIG. 5, the laminated inductor 51 has an insulating sheet 5 having coil conductor patterns 53a to 53g provided on the upper surface thereof.
2a, an insulator sheet 52k provided with coil conductor patterns 54a to 54f on the lower surface, and insulator sheets 52b to 52d, 5 provided with a plurality of semi-circular through holes 60 at the edges.
2i, 52j and folded conductor patterns 55, 57, 5
Insulator sheet 52e having 6, 58 on the upper surface,
52h and insulator sheets 52f and 52g having a plurality of circular through holes 61 at the edges thereof.

The through holes 60 and 61 are connected to each other in the stacking direction of the insulating sheets 52a to 52k, and constitute the columnar connecting conductor 60A (see FIG. 21) together with the folded conductor patterns 55, 56, 57 and 58.
In the columnar connecting conductor 60A, the portion where the through hole 61 and the folded conductor patterns 55 to 58 are formed is
It is folded back inside the spiral coil L described later (in the radial direction of the coil L).

The coil conductor patterns 53a to 53g are
It is arranged on an upper portion of a laminated body 66 (see FIG. 21) described later.
The coil conductor patterns 54 a to 54 f are arranged below the stacked body 66. The conductor patterns 53a to 53g for the coils arranged on the upper part respectively correspond to the insulator sheets 52a to 52g.
A columnar connecting conductor 60 including through holes 60 and 61 and folded conductor patterns 55 to 58 provided at the edge of 52k
The spiral coil L is configured by being electrically connected in series to the coil conductor patterns 54a to 54f sequentially arranged at the lower portion via A. The axial direction of the spiral coil L is perpendicular to the stacking direction of the insulating sheets 52a to 52k.

The above-mentioned sheets 52a to 52k are stacked, and further, protective sheets are arranged on the upper and lower sides, and then integrally fired to form a laminated body 66 as shown in FIG. The columnar connecting conductors 60 are provided on both side surfaces of the laminated body 66.
A is exposed, and end portions of the coil conductor patterns 53a and 53g are exposed on both end surfaces of the laminated body 66, respectively.

Next, as shown in FIG. 22, both side surfaces of the laminated body 66 are covered with insulating protective films 69 and 70, respectively. Resin, ceramic paste, or the like is used as the material of the insulating protective films 69 and 70.

Next, as shown in FIG. 23, input / output external electrodes 71 and 72 are provided at both ends of the laminated body 66, respectively. The input / output external electrodes 71, 72 are electrically connected to the coil conductor patterns 53a, 53g, respectively.

FIG. 24 schematically shows the internal structure of the laminated inductor 51. Insulator sheet 52a-
When 52k is made of a magnetic material such as ferrite, a minute magnetic path is formed between each of the through holes 61 of the folded portion of the spiral coil L and both side surfaces of the laminated body 66.
As a result, the DC superposition characteristic of the laminated inductor 51 is reduced to 2
It can be changed in stages. That is, the magnetic flux φ1 when the current flowing through the spiral coil L is small passes through the minute magnetic path formed between the through hole 61 and the both side surfaces of the laminated body 66 and circulates inside the inductor 51.
Therefore, the inductor 51 has a closed magnetic circuit configuration, and a large inductance is obtained.

On the other hand, when the current flowing in the spiral coil L increases and exceeds a certain value, the magnetic flux density in the minute magnetic path increases and magnetic saturation occurs, so that the inductor 51.
Inductance decreases. At this stage, the magnetic flux φ2 comes to pass outside the inductor 51, and the inductor 51
Changes to an open magnetic circuit configuration, and even if the current flowing through the spiral coil L becomes larger, the inductance is less likely to decrease.

As described above, since a large inductance is obtained when the load is low, when the inductor 51 is used in a DC / DC converter or the like, the waveform at the time of low current output can be stabilized and the stable output can be obtained even at the standby time. Is obtained. FIG. 25 shows the DC superimposition characteristic of the inductor 51 (see the solid line 74). For comparison, FIG. 25 shows FIG.
The DC superposition characteristics of the conventional laminated inductor 1 having a closed magnetic circuit structure in which the insulating sheets 2a to 2d shown in 2 are made of a magnetic material such as ferrite are also shown (dotted line 75).
reference).

In the third embodiment, the fine magnetic path is arranged substantially at the center in the thickness direction of the laminated body 66, but it may be arranged on the upper surface side or the lower surface side of the laminated body 66. Further, the minute magnetic path may be arranged only on one of the front side and the back side of the laminated body 66.
Further, when a magnetic material is used as the material of the protective sheet, the magnetic flux φ generated by the spiral coil L passes through the portion of the protective sheet, so that the through hole 61 and the folded conductor patterns 55 to 58 are particularly small. There is no need to construct a magnetic path.

Next, the laminated inductor 5 of the third embodiment
A case where 1 is mass-produced using a mother substrate will be described.

As shown in FIG. 26, the laminated inductor 5
Wide area insulating mother sheet 5 that can take multiple 1
2A is prepared, and the arrangement positions of the inductors 51 are determined vertically and horizontally. The inductors 51 are arranged so as to be adjacent to each other, and through holes are formed in the boundary portions thereof. In accordance with this position, the coil conductor patterns 53a to 53g are
While using a method such as screen printing,
A conductive paste is filled in the holes for through holes to form through holes 80.

Similarly, as shown in FIGS. 27 to 31, wide area insulating mother sheets 52B to 52K are prepared.
Insulator mother sheets 52B to 52K have through holes 80 and 81, folded conductor patterns 55 to 58, and coil conductor pattern 5 corresponding to the number of arrayed inductors 51, respectively.
4a to 54f are formed.

Next, the insulating mother sheets 52K to 52A processed in this way are stacked in this order, and further, protective mother sheets having a large area are arranged on the upper and lower sides, and then pressure is applied to form a mother laminated body. The through holes 80 and 81 and the folded conductor patterns 55 to 58 are connected to each other to form a long through hole. This mother laminated body is vertically and horizontally cut with a dicer, a laser beam, or a jet water stream, and then, as shown in FIG.
A chip-shaped laminated body, that is, a laminated body 66 as shown in FIG. 21 is cut out for each size surrounded by the one-dot chain line in FIG.
To get At this time, a part of the long through hole (the portion of the through hole 80) is divided into two to form the columnar connecting conductor 60A. The chip-shaped laminated body 66 is heated to a predetermined temperature and fired. Thereafter, as described above, both side surfaces of the laminated body 66 are covered with the insulating protective films 69 and 70 (see FIG. 2).
2). Next, as shown in FIG. 23, input / output external electrodes 71 and 72 are provided at both ends of the laminated body 66, respectively.

According to the above method, it is possible to mass-produce once, and it is possible to efficiently obtain the laminated inductor 51 at low cost.

[Other Embodiments] The present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the gist thereof.

In the case of manufacturing the laminated inductor, it is not necessarily limited to the method of stacking the conductor patterns for the coil, the insulating sheets having the through holes, etc., and then integrally firing them. The insulator sheet may be pre-baked. Moreover, you may manufacture a laminated inductor by the construction method demonstrated below. That is, after forming an insulator layer with a paste-like insulator material by printing or the like, a paste-like conductive material is applied to the surface of the insulator layer to form a coil conductor pattern. Next, a paste-like insulator material is applied onto the coil conductor pattern to form an insulator layer containing the coil conductor. Similarly, an inductor having a laminated structure can be obtained by electrically connecting necessary portions of the coil conductor through through holes while sequentially applying the layers.

Further, the columnar connecting conductor formed on the side surface of the laminated body is not limited to one in which the through hole is filled with the conductive paste, and a method of directly applying the conductive paste to the side surface of the laminated body or a plating method is also applicable. Good.

[0060]

As is apparent from the above description, according to the present invention, since the insulating protective film covers the coil conductor pattern and / or the columnar connecting conductor exposed on the surface of the laminate, it is possible to improve the accuracy. Eliminates the need for expensive processing.

Further, by exposing all of the columnar connecting conductors on both side surfaces of the laminate, an open magnetic circuit structure can be obtained even when the material of the insulating layer is a magnetic material. Therefore, the direct current superposition characteristic of the inductance can be improved.

Further, magnetic paths are formed between the coil and both side surfaces of the laminated body, and at least one columnar connecting conductor is provided on each side surface of the laminated body, and the diameter of the coil is provided over the entire length of the columnar connecting conductor. By extending in the direction to cross the magnetic path and exposing on both side surfaces of the laminated body, a nonmagnetic portion is provided in the magnetic path, and the direct current superposition characteristic is good, and
Large inductance can be obtained.

Further, all of the plurality of columnar connecting conductors are exposed on both side surfaces of the laminated body, and a part of the plurality of columnar connecting conductors is folded back into the coil, and the coil at the folded back portion and both side surfaces of the laminated body. By forming magnetic paths between them, the DC superposition characteristics can be changed in two steps.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a laminated inductor according to the present invention.

FIG. 2 is a perspective view of a laminated body configured by laminating the insulating sheets shown in FIG.

3 is a perspective view showing a state in which an insulating protective film is formed on the surface of the laminated body shown in FIG.

4 is an external perspective view of the laminated inductor shown in FIG.

5 is a schematic plan view showing the inside of the multilayer inductor shown in FIG.

FIG. 6 is a graph showing the inductance characteristic of the laminated inductor shown in FIG.

7 is a graph showing Q characteristics when the laminated inductor shown in FIG. 4 is an air-core coil.

FIG. 8 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

9 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

FIG. 10 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

FIG. 11 is an exploded perspective view showing a second embodiment of the multilayer inductor according to the present invention.

12 is a perspective view of a laminated body formed by laminating the insulating sheets shown in FIG.

13 is a perspective view showing a state in which an insulating protective film is formed on the surface of the laminated body shown in FIG.

14 is an external perspective view of the laminated inductor shown in FIG.

15 is a schematic plan view showing the inside of the multilayer inductor shown in FIG.

16 is a graph showing the inductance characteristic of the laminated inductor shown in FIG.

FIG. 17 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

FIG. 18 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

FIG. 19 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG.

FIG. 20 is an exploded perspective view showing a third embodiment of the multilayer inductor according to the present invention.

21 is a perspective view of a laminated body formed by laminating the insulating sheets shown in FIG.

22 is a perspective view showing a state in which an insulating protective film is formed on the surface of the laminated body shown in FIG.

23 is an external perspective view of the multilayer inductor shown in FIG.

24 is a schematic plan view showing the inside of the multilayer inductor shown in FIG.

FIG. 25 is a graph showing the inductance characteristic of the laminated inductor shown in FIG. 23.

FIG. 26 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23.

FIG. 27 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23.

28 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23. FIG.

29 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23. FIG.

30 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23. FIG.

FIG. 31 is a plan view showing an insulating mother sheet used for producing the laminated inductor shown in FIG. 23.

FIG. 32 is an exploded perspective view showing a conventional laminated inductor.

FIG. 33 is a schematic plan view showing the inside of the multilayer inductor shown in FIG. 32.

[Explanation of symbols]

11, 31, 51 ... Multilayer inductors 12a-12e, 32a-32e, 52a-52k ... Insulator sheets 13a-13g, 14a-14f, 34a-34g, 3
5a to 35f, 53a to 53g, 54a to 54f ... Coil conductor patterns 15A, 36A, 37A, 60A ... Columnar connecting conductors 16, 38, 66 ... Laminated body 17 ... Insulating protective film 33 ... Protective sheets 39, 40, 69, 70 ... Insulating protective films 12A-12E, 32A-32E, 52A-52K ... Insulator mother sheets 25, 46, 47, 80, 81 ... Through holes 55-58 ... Folding conductor pattern L ... Helical coil

Claims (7)

[Claims] 1. A laminated body formed by stacking a plurality of insulating layers, a plurality of coil conductor patterns arranged on an upper portion of the laminated body, and a plurality of coil conductors arranged on a lower portion of the laminated body. A pattern, a plurality of columnar connecting conductors which are respectively arranged on both sides of the laminated body and at least one of which is exposed on both side surfaces of the laminated body, and a coil which is exposed on the surface of the laminated body And an insulating protective film for covering the columnar connecting conductor, and the upper and lower coil conductor patterns are alternately and electrically connected in series through the columnar connecting conductor. The coil has a coil axis in a direction perpendicular to the stacking direction of the insulating layers, the laminated inductor. 2. The laminated inductor according to claim 1, wherein all of the plurality of columnar connecting conductors are exposed on both side surfaces of the laminated body. 3. The plurality of columnar connecting conductors are respectively arranged in the vicinity of both side portions of the laminated body, and magnetic paths are formed between the coil and both side surfaces of the laminated body, respectively.
At least one of the columnar connecting conductors on each of both side surfaces of the multilayer body extends in the radial direction of the coil over the entire length of the columnar connecting conductor, traverses the magnetic path, and is exposed on both side surfaces of the multilayer body. The laminated inductor according to claim 1, wherein: 4. The laminated inductor according to claim 2, wherein the magnetic path formed in the laminated body is a non-closed magnetic path. 5. The plurality of columnar connecting conductors are all exposed on both side surfaces of the laminated body, and a part of the plurality of columnar connecting conductors is folded back into the coil, and the coil at the folded back portion and the coil The multilayer inductor according to claim 1, wherein magnetic paths are formed between the two side surfaces of the multilayer body. 6. The multilayer inductor according to claim 5, wherein a magnetic path that changes in two steps, a closed magnetic path and an open magnetic path, is formed in the laminated body according to a current value flowing in the coil. . 7. An insulating mother sheet provided with through holes and an insulating mother sheet provided with a plurality of coil conductor patterns are stacked and integrally fired to fire the mother laminated body, and the through holes are provided. To form a long through hole, and the mother laminated body is cut at the position of the long through hole to cut out a chip-shaped laminated body of a predetermined size, and the long through hole is formed. Through a columnar connecting conductor formed by dividing into two, the conductor patterns for coils respectively arranged on the upper part and the lower part of the chip-shaped laminated body are alternately electrically connected in series, and the insulating sheet is stacked in the stacking direction. And forming a coil having a coil axis in a vertical direction, and a conductor pattern for a coil and / or a columnar connecting conductor exposed on the surface of the chip-shaped laminate. The method of fabricating the multilayer inductor for forming an insulating protective film for covering, comprising the a.