JP3731284B2 - Multilayer chip inductor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer chip inductor.
[0002]
[Prior art]
This type of conventional multilayer chip inductor is configured, for example, as shown in FIGS. In addition, the arrow X shown in FIG. 6 shows the lamination direction of a green sheet. As shown in FIG. 6, the multilayer chip inductor 1 includes a coiled inner conductor 3 wound in a coil shape inside a ceramic multilayer body 2, and ends of the coiled inner conductor 3 are drawn conductors 4, 5 is electrically connected to the external electrodes 6 and 7 through 5. The external electrodes 6 and 7 are formed on the end surface of the ceramic laminate 2 and on the peripheral side surface of the ceramic laminate 2 in the vicinity of the end surface extending from the end surface.
[0003]
As shown in FIG. 7, the ceramic laminate 2 is obtained by laminating magnetic ceramic green sheets 10, 10, 10, 11 to 20, 10, 10, and 10 in order from the bottom, pressing and sintering. .
[0004]
The green sheet 10 is a dummy green sheet on which no internal conductor is formed. In the green sheets 11 to 20, the inner conductors 24 to 33 having less than one turn are formed on the respective surfaces. Furthermore, the green sheets 12 to 20 are provided with via holes at one end of the internal conductors 25 to 33, and when the green sheets 11 to 20 are stacked, the internal conductors 24 to 33 are sequentially conducted through the respective via holes. Thus, the coiled inner conductor 3 is formed. Furthermore, the lead conductors 4 and 5 are formed in the green sheets 11 and 20 so as to be electrically connected to one end of the internal conductors 24 and 33 and exposed to one side surface of the green sheets 11 and 20.
In the multilayer chip inductor 1 having such a configuration, the lead conductors 4 and 5 exposed to one surface of the peripheral side surface of the ceramic multilayer body 2 are electrically connected to the external electrodes 6 and 7.
[0005]
[Problems to be solved by the invention]
However, the lead conductors 4 and 5 are only exposed on one surface of the peripheral side surface of the ceramic laminate 2 with a thin conductor, and the area of the exposed portion is small. Therefore, the reliability of conduction between the coiled inner conductor 3 and the outer electrodes 6 and 7 is low. Further, when the ceramic laminated body 2 is fired, if a part of the exposed portion of the lead conductors 4 and 5 is scattered, the conduction between the coiled inner conductor 3 and the outer electrodes 6 and 7 may be interrupted. Had the problem of low reliability.
[0006]
In addition, when the circuit board on which the multilayer chip inductor 1 is mounted is deformed, for example, internal stress may occur in the multilayer chip inductor 1. When the internal stress acts in a direction that separates the conductive portions between the lead conductors 4 and 5 and the external electrodes 6 and 7 of the multilayer chip inductor 1, there is a problem that the conductive portion is disconnected.
[0007]
An object of the present invention is to solve the above-described problems, and the conductive portion between the lead conductor of the coiled inner conductor and the external electrode is provided at a plurality of locations on the end face and the peripheral side face of the multilayer chip inductor. At the same time, it is an object of the present invention to provide a multilayer chip inductor having a large conduction area and high electrical connection reliability between a coiled inner conductor and an external electrode.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the multilayer chip inductor of the present invention, a ceramic multilayer body, a coiled inner conductor formed inside the ceramic multilayer body, an end surface of the ceramic multilayer body, and an extension from the end surface are provided. And an external electrode formed on the peripheral side surface of the ceramic laminate near the end surface, and the coiled inner conductor has each end of the inner conductor on the end surface and the peripheral side surface of the ceramic laminate. It is exposed and is connected to the external electrode through this end.
[0009]
Further, each end of the inner conductor of the coil-shaped inner conductor is exposed on the end face of the ceramic laminate and a plurality of peripheral side faces, and is electrically connected to the external electrode through the end.
The coiled inner conductor is formed on the laminated surface of the ceramic laminate.
[0010]
The external electrode is formed on an end surface substantially orthogonal to the stacking direction of the ceramic laminate and a peripheral side surface near the end surface, or an end surface substantially parallel to the stacking direction of the ceramic laminate and a peripheral side surface near the end surface. Is formed.
[0011]
Thereby, even if the thickness of the coiled inner conductor is thin, the area where each end of the coiled inner conductor is exposed to the end face and the peripheral side surface of the ceramic laminate can be widened. The conduction area with the external electrode can be increased.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment according to the present invention will be described in detail with reference to FIGS. 1, 2 and 3. FIG. However, as can be understood by comparing FIG. 2 and FIG. 7 of the conventional example, the green sheet 46 in which the via hole 47 is formed is different from the green sheet 10 of the conventional example, and the lead conductors formed in the green sheets 48 and 49 are different. 44b and 45b are different from the lead conductors 4 and 5 of the conventional example. The same parts as those of the above-described conventional example are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, the arrow X shown in FIG. 1 shows the lamination direction of a green sheet.
[0013]
As shown in FIG. 1, the multilayer chip inductor 41 includes a coil-shaped inner conductor 43 inside a ceramic multilayer body 42. External electrodes 6 and 7 are formed on the end face of the ceramic laminate 42 and the peripheral side surface in the vicinity of the end face extending from the end face, and the respective ends of the coiled inner conductor 43 and the external electrodes 6 and 7 are electrically connected. Conductors 44a, 44b, 45a, 45b are provided. Specifically, the lead conductors 44 a and 45 a are formed so as to be conductive to the end face of the ceramic multilayer body 42, and the lead conductors 44 b and 45 b are formed so as to be conductive to the peripheral side surface of the ceramic multilayer body 42.
[0014]
As shown in FIG. 2, the ceramic laminate 42 is formed by laminating and pressing green sheets 46, 46, 46, 48, 12 to 19, 49, 46, 46, 46 of insulating ceramics such as magnetic bodies in order from the bottom. Obtained by sintering.
[0015]
The green sheet 46 is provided with via holes 47 at predetermined positions so as to be electrically connected to the lead conductors 44 b and 45 b and the external electrodes 6 and 7 formed in the green sheets 48 and 49. In the via hole 47, lead conductors 45a and 45b are formed. When the green sheets 48, 12 to 19 and 49 are laminated in order from the bottom, the internal conductors 25 to 32 are integrally formed. The coiled inner conductor 43 is electrically connected to each end. One end of each of the lead conductors 44 a and 45 a is exposed at both end faces that are substantially orthogonal to the lamination direction of the ceramic laminate 42.
[0016]
In the green sheets 48 and 49, lead conductors 44b and 45b are formed on one end side of the respective surfaces, and at predetermined positions so as to be electrically connected to one end of the internal conductors 25 and 32 formed on the green sheets 12 and 19. Via holes will be provided in The lead conductors 44 b and 45 b are electrically connected to each end of the coiled inner conductor 43 and are exposed on the peripheral side surface of the ceramic laminate 42.
[0017]
As shown in FIG. 3, the multilayer chip inductor 41 is obtained by forming the external electrodes 6 and 7 on the end face that is substantially orthogonal to the stacking direction of the ceramic laminate 42 and the peripheral side surface in the vicinity of the end face.
[0018]
The coiled inner conductor 43 of the multilayer chip inductor 41 having such a configuration is electrically connected to the external electrodes 6 and 7 through the lead conductors 44a and 45a at the end face of the ceramic multilayer body 42, and is drawn out at the peripheral side surface of the ceramic multilayer body 42. Conductive to the external electrodes 6 and 7 through 44b and 45b.
[0019]
Another embodiment according to the present invention will be described in detail with reference to FIGS. However, as can be understood by comparing FIG. 4 and FIG. 1, the formation direction of the external electrode differs by 90 ° with respect to the lamination direction of the green sheets. The same reference numerals are assigned and detailed description is omitted. In addition, the arrow X shown in FIG. 4 shows the lamination direction of a green sheet.
[0020]
As shown in FIG. 4, the multilayer chip inductor 51 includes a coil-shaped inner conductor 53 inside the ceramic multilayer body 52, and the peripheral surface of the ceramic multilayer body 52 in the vicinity of the end surface extending from the end surface of the ceramic multilayer body 52. External electrodes 56 and 57 are formed on the side surfaces. Lead conductors 54a and 54b and lead conductors 55a and 55b are provided at each end of the coiled inner conductor 53 so that the coiled inner conductor 53 and the outer electrodes 56 and 57 are electrically connected. Specifically, the lead conductors 54 a and 55 a are formed so as to be conductive to the peripheral side surface of the ceramic multilayer body 52, and the lead conductors 54 b and 55 b are formed so as to be conductive to the end face of the ceramic multilayer body 52.
[0021]
As shown in FIG. 5, the ceramic laminate 52 is formed by laminating and pressing green sheets 46, 46, 46, 58, 13 to 19, 59, 46, 46, 46 of insulating ceramics such as magnetic bodies in order from the bottom. Obtained by sintering.
[0022]
The green sheets 58 and 59 have inner conductors 60 and 61 with less than one turn formed on their respective surfaces, and are drawn out at one end of the inner conductors 60 and 61 so as to be exposed on one side of the green sheets 58 and 59. Conductors 54b and 55b are formed. Further, the green sheet 58 is provided with a via hole at the end of the internal conductor 60, and the green sheet 59 is provided with a via hole at the end of the internal conductor 61, and the green sheets 58, 13 to 19, 59 are attached. When laminated, the inner conductors 60, 26 to 32, 61 are sequentially conducted through the respective via holes to constitute the coiled inner conductor 53.
[0023]
The multilayer chip inductor 51 is obtained by forming the external electrodes 56 and 57 on the end surface substantially parallel to the stacking direction of the ceramic multilayer body 52 and the peripheral side surface in the vicinity of the end surface.
[0024]
The coiled inner conductor 53 of the multilayer chip inductor 51 having such a configuration is electrically connected to the external electrodes 56 and 57 through the lead conductors 54 b and 55 b at the end face of the ceramic multilayer body 52, and is drawn from the peripheral side surface of the ceramic multilayer body 52. Conduction to external electrodes 56 and 57 through 54a and 55a.
[0025]
The multilayer chip inductor according to the present invention is not limited to the above embodiment, and can be variously modified within the scope of the gist thereof.
For example, although the lead conductors 44a and 45a of the multilayer chip inductor 41 shown in one embodiment are provided one by one, the lead conductors 44a and 45a are provided at a plurality of places, and similarly the lead conductors 44b and 45b. More preferably, it is provided on a plurality of end faces of the green sheets 48 and 49 to increase the conductive area with the external electrodes 6 and 7.
[0026]
Needless to say, it is possible to obtain a predetermined number of turns and to obtain a predetermined inductance for the coiled inner conductor by appropriately increasing / decreasing the number of laminated green sheets.
[0027]
【The invention's effect】
As described above, in the multilayer chip inductor according to the present invention, each lead conductor of the coiled inner conductor is exposed on the end face and the peripheral side surface of the ceramic laminate and is electrically connected to the external electrode, so that the conduction area is widened. The reliability of electrical connection between each end of the coiled inner conductor and the external electrode can be increased.
[0028]
In addition, the lead conductor is exposed on each of the end face and the peripheral side surface of the ceramic multilayer body, that is, because it is electrically connected to the external electrode in different directions, the circuit board on which the multilayer chip inductor is mounted is deformed. Even if internal stress is generated in the multilayer chip inductor, since the stress is normally unidirectional, either the end face of the multilayer chip inductor or the lead conductor on the peripheral side surface is electrically connected to the external electrode, and the coil The reliability of electrical connection between each end of the inner conductor and the external electrode can be increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a multilayer chip inductor according to one embodiment of the present invention.
FIG. 2 is a perspective view of the multilayer chip inductor of FIG. 1 before lamination.
3 is a perspective view of the multilayer chip inductor of FIG. 1. FIG.
FIG. 4 is a cross-sectional view of a multilayer chip inductor according to another embodiment of the present invention.
5 is a perspective view of the multilayer chip inductor of FIG. 4 before lamination.
FIG. 6 is a cross-sectional view of a conventional multilayer chip inductor.
FIG. 7 is a perspective view of a conventional multilayer chip inductor before lamination.
[Explanation of symbols]
6, 7 External electrode 41 Multilayer chip inductor 42 Ceramic multilayer body 43 Coiled inner conductors 44a, 44b, 45a, 45b Lead conductor 51 Multilayer chip inductor 52 Ceramic multilayer body 53 Coiled inner conductors 54a, 54b, 55a, 55b Conductors 56 and 57 External electrode X Lamination direction

Claims (5)

A ceramic laminate, a coiled inner conductor formed inside the ceramic laminate, an end face of the ceramic laminate, and an external electrode extending from the end face and formed on the peripheral side surface of the ceramic laminate near the end face And,
The coiled inner conductor has each end portion of the inner conductor exposed at the end face and the peripheral side surface of the ceramic laminate, and is connected to the external electrode through the end portion. Type chip inductor. The coiled inner conductor is characterized in that each end of the inner conductor is exposed on an end face and a plurality of peripheral side surfaces of the ceramic laminate, and is electrically connected to the external electrode through the end. The multilayer chip inductor according to claim 1. 3. The multilayer chip inductor according to claim 1, wherein the coiled inner conductor is formed on a multilayer surface of the ceramic multilayer body. 4. The multilayer chip inductor according to claim 1, wherein the external electrode is formed on an end surface substantially orthogonal to a stacking direction of the ceramic multilayer body and a peripheral side surface in the vicinity of the end surface. 4. The multilayer chip inductor according to claim 1, wherein the external electrode is formed on an end face substantially parallel to the lamination direction of the ceramic laminate and a peripheral side face in the vicinity of the end face.

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