JP3410876B2 - Planar inductors, electronic components mounted with planar inductors - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar inductor used for a DC-DC converter of a stabilized power supply unit in a small portable electronic device, and an electronic component mounted with the planar inductor.

[0002]

2. Description of the Related Art Recently, portable electronic devices are becoming smaller and smaller, and a surface mount inductor is used for a DC-DC converter of a stabilized power supply unit used in such small electronic devices. Has been.

Conventionally, as such an inductor, there is a winding type in which a coil 2 is wound around a magnetic core 1 as shown in FIG. 8 and is integrated by a molding resin 3. Such a wire-wound inductor has a drawback that it is not suitable for thinning because the shape becomes larger as the voltage ratio increases and the capacitance increases.

Therefore, conventionally, a planar inductor configured as shown in FIGS. 9 (a) and 9 (b) has been used as a device which can be made smaller and thinner. In such a planar inductor, as the inductor body 4, two spiral coils 41 and 42 are arranged on the same plane, and the coils 41 and 42 are electrically connected in series. Electrode pads 411 and 421 for connecting the winding start ends and winding ends of the coils 41 and 42 are provided at the center of the winding of the coils 41 and 42. Then, the magnetic films 51, 42 are formed on both surfaces of the coils 41, 42 with an insulating layer interposed therebetween.
52 is provided. In this case, the magnetic film 51 is
Openings 511 are formed in portions of the Nos. 1 and 42 corresponding to the electrode pads 411 and 421, and the electrode pads 411 and 421 are exposed to the outside through these openings 511.

The inductor body 4 is mounted on the die pad 7 of the resin substrate 6, and the magnetic film 51 is provided between the electrode pads 411 and 421 of the coils 41 and 42 and the wiring 8 on the resin substrate 6. Openings 511, 51
Connect with bonding wires 91, 91 via 2,
The entire inductor body 4 including the bonding wires 91 and 92 is sealed with the potting resin 10.

[0006]

However, in the planar inductor configured as described above, spiral coils are used as the coils 41 and 42, and the electrode pads 411 and
421 is provided, and a bonding wire 9 is provided between the electrode pads 411 and 421 and the wiring 8 on the resin substrate 6.
Since the bonding wires 91 and 92 are connected to each other, the lengths of the bonding wires 91 and 92 are relatively large, and the area of the electrode pads 411 and 421 to which the bonding wires 91 and 92 are connected is large. Is small, and the number of wires that can be bonded is limited to about two.

Therefore, the bonding wires 91, 9
The resistance loss in the connection portion with the second electrode pad 411, 421 increases, and further, the bonding wire 91, 9
Since 2 is exposed, noise may leak to the outside, and stable performance cannot be obtained. If such a planar inductor is applied to the above-mentioned DC-DC converter, the converter operation is adversely affected. There was a risk of giving.

An object of the present invention is to provide a planar inductor capable of obtaining stable performance and realizing stable mounting of the planar inductor, and an electronic component mounted with the planar inductor.

[0009]

The invention according to claim 1 is
In a planar inductor in which a magnetic film is provided on both sides of the coil via an insulating layer, the coil is arranged in a plane.
Placed rectangular spiral coil,
In the longitudinal direction of the coil end of the center of the spiral coil
It is composed of two electrodes arranged at a predetermined interval along with conductive projections provided on these electrodes and exposed to the outside.

Further, the inventions of claim 2, wherein the coil sided
Planarizer in which a magnetic film is provided on an insulating layer
In the inductor, the coil has a length arranged in a plane.
It is a rectangular spiral coil, and the rectangular spiral coil
Elongate along the longitudinal direction of the coil end at the center of the il winding
And the electrodes arranged in a line and provided along this electrode
Both are composed of conductive protrusions exposed to the outside .

According to a third aspect of the present invention , in the first or second aspect , the coil includes two rectangular spirals.
The spiral coils are arranged in the same plane and these spiral coils are
The coils are electrically connected in series.

[0012] inventions as claimed in claim 4, claim 1 or 2
When the described planar inductor is mounted on the board,
The conductive inductor provided on the electrode of the planar inductor.
Direct connection of the protrusion to the wiring of the board by face down
is doing.

According to a fifth aspect of the invention , insulation is provided on both sides of the coil.
Plane Inducer with a magnetic film provided between layers
The coil has two coils arranged in the same plane.
Rectangular spiral coil of these spirals
The coils are electrically connected in series and the length of the two
Square spiral coil The coil at the center of each winding
Each one is placed at one end of the end in the longitudinal direction.
The poles and these electrodes are provided and exposed to the outside
Conductive protrusions and the triangular vertices together with the protrusions.
And other supporting protrusions arranged at the
ing. According to the invention of claim 6, the play of claim 5
Mounting the planar inductor on the board and
Face the protrusions provided on the inductor and the supporting protrusions.
It is directly connected to the wiring of the substrate by the down.

As a result, according to the first , second, third, and fifth aspects of the invention, the coil electrode can be directly connected to the wiring of the substrate by the face-down via the conductive protrusion. Further, according to the inventions of claims 4 and 6, in the state where the planar inductor is mounted on the substrate, the conductive protrusion of the electrode of the planar inductor can be directly connected to the wiring on the substrate. It is possible to reduce the resistance loss and to prevent the generation of noise.

Further, according to the invention described in claims 4 and 6 , there is no room for rattling when directly connecting to the wiring on the substrate by face down, and stable mounting work of the planar inductor can be realized. .

[0016]

DETAILED DESCRIPTION OF THE INVENTION

(First Embodiment) FIG. 1 shows a schematic configuration of the first embodiment. In the figure, reference numeral 11 denotes an inductor body. In the inductor body 11, two rectangular spiral coils 111 and 112 are arranged on the same plane, and the coils 111 and 112 are electrically connected in series.

The electrode pads 111a, 11 connected to the ends of the coil 111 are connected to the center of the winding of the coil 111.
1b are arranged at predetermined intervals along the longitudinal direction of the rectangular spiral coil 111. In this case, these electrode pads 111a and 111b are electrically connected.

Similarly, the electrode pads 112a, 11 connected to the ends of the coil 112 at the center of the winding of the coil 112.
2b are arranged at predetermined intervals along the longitudinal direction of the rectangular spiral coil 112. These electrode pads 1
12a and 112b are also electrically connected.

Then, conductive projections 12 such as AU balls are provided on the electrode pads 111a, 111b and 112a, 112b. Magnetic films 121 and 121 are provided on both surfaces of the coils 111 and 112 via an insulating layer.

Then, in the one magnetic film 121 located on the front surface side of the inductor body 11, openings are formed at respective locations (4 locations) corresponding to the electrode pads 111a and 111b of the coil 111 and the electrode pads 112a and 112b of the coil 112, respectively. 121a are formed and these openings 121a are formed.
Via the respective electrode pads 111a, 111b and 112
The protrusions 12 of a and 112b are exposed to the outside from the surface of the inductor body 11.

In addition, as shown in FIG. 2B, which will be described later, a mark 13 for alignment is attached to a corner of the back surface of the inductor body 11. Then, the inductor body 11 thus configured is aligned with the alignment mark 13 with respect to the wirings 15 and 16 arranged in parallel on the substrate 14 as shown in FIGS. Then connect by face down. In this case, the wiring 15, 16
A conductive adhesive 17 is applied on the upper surface of the coil 111.
The protrusion 12 of FIG.
The projections 12 of 12a and 112b are connected to the wiring 16, respectively.

Then, the inductor body 11 is sealed by forming the sealing resin 18 by printing. Therefore, with this configuration, the electrode pads 111a, 11a of the inductor body 11 can be formed by the face-down connection.
Since the protrusions 12 of 1b and 112a, 112b can be directly connected to the wirings 15, 16 on the substrate 14, the resistance loss can be reduced and the bonding can be performed as compared with the conventional bonding wire. Stable performance can be obtained, such as the prevention of noise due to the exposure of the wire.
When applied to a C converter or the like, it can contribute to stable operation of the converter.

The face-down connection of the inductor body 11 to the wirings 15 and 16 on the substrate 14 is as follows.
Electrode pads 1 arranged at four locations on the inductor body 11
Since the protrusion 12 of 11a, 111b, 112a, 112b is placed on the wirings 15, 16, there is no room for rattling during such connection work, and stable mounting work of the planar inductor is realized. become able to. This is particularly stable and stable when connecting by automatic assembly.
Moreover, efficient work can be secured.

Further, the wiring 1 on the substrate 14 is formed by the alignment mark 13 formed on the back surface of the inductor body 11.
Since the positions 5 and 16 are aligned and the connection is made by face down, the resin sealing work by printing can be performed accurately, including when mounting.

In the above-described embodiment, the electrode pads 11 arranged at four positions of the inductor body 11 face down on the wirings 15 and 16 arranged on the substrate 14.
Although the protrusions 1a, 111b, 112a, 112b are placed and connected to prevent rattling at the time of connection work, the protrusions 12 are the electrode pads 111.
a and 112a only, and other supporting protrusions are provided at the position on the surface side of the inductor body 11 that forms a triangular vertex with these protrusions 12, and these three protrusions support play at the time of connection work. It may be prevented. (Second Embodiment) FIGS. 3 (a) and 3 (b) show a schematic configuration of the second embodiment, and the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. .

In this case, the inductor body 11 has the electrode pads 111c and 112c arranged at the center of the winding of the spiral coils 111 and 112, respectively, and formed in an elongated shape along the longitudinal direction of the coils 111 and 112. There is. Further, the magnetic film 121 provided on the surfaces of the coils 111 and 112 with the insulating layer interposed therebetween is
The openings 121a corresponding to c and 112c are formed.

Then, protrusions 21 are formed from AU or CU along the elongated electrode pads 111c and 112c, and these protrusions 21 are projected on the surface of the inductor body 11.

The inductor body 11 having such a configuration is also positioned face down after being aligned with the wirings 15 and 16 on the substrate 14 by the alignment mark 13. Also in this case, the wiring 15,
A conductive adhesive 17 is applied to the upper surface of the coil 16, and the electrode pad 11 of the coils 111 and 112 is coated with the conductive adhesive 17.
The protrusions 21 of the wirings 15 and 16
Connected to.

Then, the sealing resin 17 is formed by printing so as to seal the whole. Therefore, in this way, the face-down connection of the inductor body 11 to the wirings 15 and 16 on the substrate 14 is performed by the elongated electrode pads 111c and 11c of the inductor body 11.
Since the projection 21 of 2c is placed on the wirings 15 and 16, it is possible to further prevent rattling during assembly and obtain a stable connection. Of course, even in this case, the same effect as that of the first embodiment can be expected. (Third Embodiment) FIGS. 4 (a) and 4 (b) show a schematic configuration of the third embodiment, and the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. .

In this case, the inductor body 11 is the same as that described in FIG. The substrate 31 on which the inductor body 11 is mounted has a groove 311 formed on the surface thereof, and the wirings 32 and 33 are arranged parallel to the bottom surface of the groove 311. These wirings 32 and 33 are connected to the wirings 15 and 16 on the surface of the substrate 31 through through holes 34 and 35, respectively.

Then, the inductor body 11 is inserted face down into the groove 311 and the wiring 3 on the bottom surface of the groove 311 is inserted.
Connect to 2, 33. In this case, the conductive adhesive 17 is applied on the wirings 32 and 33, and the adhesive 17
Thus, the protrusions 12 of the electrode pads 111a and 111b of the coil 111 are connected to the wiring 32, and the electrode pads 112 of the coil 12 are
The protrusions 12 a and 112 b are connected to the wiring 33, respectively.

The groove 311 in which the inductor body 11 is inserted is coated with the sealing resin 18 so that the surface of the substrate 31 is made flat and the inductor body 11 is sealed.

Therefore, in this way, the inductor body 11 is inserted face down into the groove 311 formed on the surface of the substrate 31, and the wiring 3 arranged on the bottom surface of the groove 311.
Since the surface of the substrate 31 can be flattened and the inductor body 11 can be sealed by connecting to the grooves 33 and 33 and coating the sealing resin 18 on the groove 311, the overall thickness can be further reduced. Of course, even in this case, the same effect as that of the above-described first embodiment can be expected. (Fourth Embodiment) FIGS. 5A and 5B show a schematic configuration of the fourth embodiment. In this case, the electrode pads 111a and 111b of the inductor body 11 and the electrode pads of the coil 112 are shown. The projections 41 formed on 112a and 112b are made of AU balls or a conductive adhesive, and the AU balls or the projections 41 of a conductive adhesive are made face-down by the conductive adhesive applied to the substrate 42 for each electrode pad. 111a, 111b and 112
The wirings a and 112b are connected to the wiring 43 of the substrate 42.

Even in this case, the same effect as that of the above-described first embodiment can be expected. (Fifth Embodiment) FIGS. 6A and 6B show a schematic configuration of the fifth embodiment. In this case, the electrode pads 111a and 111b of the inductor body 11 and the electrode pads of the coil 112 are shown. The protrusion 51 formed on each of 112a and 112b is composed of a plurality of solder balls, and each electrode pad 111a, 111b and 112a, 112b is formed by the protrusion 51 of the solder ball by face down.
Is connected to the wiring 53 of the substrate 52.

Even in this case, the same effect as that of the above-described first embodiment can be expected. Note that FIG.
As shown in (b), a plurality of ingot main bodies 11 described above may be directly connected to the substrate 61 by face down, and thereafter, they may be integrated by batch coating by printing using the metal mask 62.

In this way, since it is possible to perform resin encapsulation all at once by printing, it is possible to significantly improve the work efficiency as compared with resin encapsulation of each ingot body 11.

[0037]

As described above, according to the present invention, the coil electrode can be directly connected to the wiring of the substrate through the conductive projection by face down, and the resistance loss at the connection portion can be reduced. At the same time, noise can be prevented from occurring. Further, there is no room for rattling when directly connecting to the wiring on the substrate by face down, and stable mounting work of the planar inductor can be realized. This makes it possible to secure stable and efficient work without causing an error in the work particularly when connecting by automatic assembly.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an inductor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a mounted state of the inductor according to the first embodiment.

FIG. 3 is a diagram showing a schematic configuration of a mounted state of an inductor according to a second embodiment.

FIG. 4 is a diagram showing a schematic configuration of a mounted state of an inductor according to a third embodiment.

FIG. 5 is a diagram showing a schematic configuration of a mounted state of an inductor according to a fourth embodiment.

FIG. 6 is a diagram showing a schematic configuration of a mounted state of an inductor according to a fifth embodiment.

FIG. 7 is a diagram showing a schematic configuration of a mounted state of an inductor according to a sixth embodiment.

FIG. 8 is a diagram showing a schematic configuration of an example of a conventional inductor.

FIG. 9 is a diagram showing a schematic configuration of another example of a conventional inductor.

[Explanation of symbols]

11 ... Inductor body, 111, 112 ... Spiral coil, 111a, 111b, 111c, 112a, 112b,
112c ... Electrode pad, 12, 21, 41, 51 ... Protrusion, 121 ... Magnetic film, 121a ... Opening part, 13 ... Alignment mark, 14, 31, 42, 61 ... Substrate, 15, 16, 32, 33, 43 ... Wiring, 17 ... Conductive adhesive, 18 ... Sealing resin, 34, 35 ... Through hole, 61 ... Metal mask.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-21791 (JP, A) JP-A-6-96940 (JP, A) JP-A-6-53043 (JP, A) JP-A-6- 260341 (JP, A) JP-A-1-157507 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 17/00 H01F 27/29

Claims (6)

(57) [Claims] 1. A planar inductor in which a magnetic film is provided on both sides of a coil with an insulating layer interposed therebetween, wherein the coil is a rectangular spiral coil arranged in a plane.
And the coil end of the central part of the winding of the rectangular spiral coil
A planar inductor comprising: two electrodes arranged at a predetermined interval along the longitudinal direction of the above, and conductive projections provided on these electrodes and exposed to the outside. 2. A magnetic film is provided on both sides of the coil with an insulating layer interposed therebetween.
In a planar inductor designed to be driven, the coils are rectangular spiral coils arranged in a plane.
And the coil end of the central part of the winding of the rectangular spiral coil
Of the electrodes arranged in a slender shape along the longitudinal direction of the, and provided along the electrodes and exposed to the outside.
A planer having a conductive protrusion.
Inductor. Wherein the coil comprises two rectangular spiral coils are arranged on the same plane, the planar inductor according to claim 1 or 2, wherein between the spiral coils is characterized in that it is electrically connected in series . 4. The planar inductor according to claim 1 or 2 is mounted on a substrate, and conductive projections provided on the electrodes of the planar inductor are directly connected to the wiring of the substrate by face down. An electronic component mounted with a planar inductor. 5. A magnetic film is provided on both sides of the coil with an insulating layer interposed therebetween.
In the planar inductor configured as described above, the coils are two rectangular spars arranged in the same plane.
The spiral coils are electrically connected between these spiral coils.
In the winding of each of the two rectangular spiral coils , which are connected in series in the air.
Located at one end in the longitudinal direction of the coil end of the core
Each one electrode, and the conductivity provided on these electrodes and exposed to the outside
And the protrusions that form a triangle and form a triangular vertex with the protrusions.
And other supporting protrusions
Inductor. 6. A planar inductor according to claim 5,
Mounted on a board and provided on the planar inductor
Front and front protrusion
Planar characterized by being directly connected to the wiring of the substrate
An electronic component that mounts an inductor.