JPH10284324A - Multilayer chip inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer chip inductor exhibiting a high reliability of electrical connection by increasing the connecting area of a connecting part between inner and outer electrodes. SOLUTION: A multilayer chip inductor 41 is provided with a ceramic laminate 42, an inner conductor 43 in the form of a coil formed in the ceramic laminate 42 and outer electrodes 6 and 7 formed on ends of the ceramic laminate 42 and on the perimeter of the ceramic laminate 42 near the ends extending from the ends. The ends of the inner conductor 43 in the form of a coil are exposed at the ends and on the perimeter of the ceramic laminate 42 and the inner conductor 43 has a continuity with the outer electrodes 6 and 7 through its ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer chip inductor.

[0002]

2. Description of the Related Art A conventional multilayer chip inductor of this type is configured as shown in FIGS. 6 and 7, for example.
Note that the arrow X shown in FIG. 6 indicates the laminating direction of the green sheets. As shown in FIG. 6, the multilayer chip inductor 1 includes a coiled internal conductor 3 wound in a coil shape inside a ceramic laminate 2, and each end of the coiled internal conductor 3 is a lead conductor 4. 5 and the external electrodes 6 and 7 are electrically connected. The external electrodes 6 and 7 are formed on the peripheral surface of the ceramic laminate 2 near the end face of the ceramic laminate 2 and the end face extending from the end face.

As shown in FIG. 7, a ceramic laminate 2 is made of magnetic ceramic green sheets 10, 10, 1.
0, 11 to 20, 10, 10, and 10 are laminated in order from the bottom,
It is obtained by pressing and sintering.

The green sheet 10 is a dummy green sheet on which no internal conductor is formed. The green sheets 11 to 20 have less than one turn of internal conductors 24 to 33 formed on their respective surfaces. Green sheet 12
20 are provided with via holes at one ends of the internal conductors 25 to 33. When the green sheets 11 to 20 are laminated, the internal conductors 24 to 33 are sequentially conducted through the respective via holes to form a coil. The inner conductor 3 is constituted. Furthermore, the inner conductors 24, 3
The lead conductors 4 and 5 are formed so as to be connected to one end of the green sheet 3 and exposed on 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 on one surface of the peripheral side surface of the ceramic multilayer body 2 and the external electrodes 6 and 7 are electrically connected.

[0005]

However, the lead conductors 4, 5 have a small thickness and are exposed only on one surface of the peripheral side surface of the ceramic laminate 2, and the area of the exposed portion is small. . Therefore, the coiled inner conductor 3
And the external electrodes 6 and 7 have low reliability of conduction. Further, when a part of the exposed portions of the lead conductors 4 and 5 is scattered during firing of the ceramic laminate 2, conduction between the coil-shaped internal conductor 3 and the external electrodes 6 and 7 may be interrupted. Has a problem of low reliability.

Further, when the circuit board on which the multilayer chip inductor 1 is mounted is deformed such as by bending, internal stress may be generated in the multilayer chip inductor 1. When the internal stress acts in a direction to separate the conductive portions between the lead conductors 4 and 5 of the multilayer chip inductor 1 and the external electrodes 6 and 7, there is a problem that the conductive portions are disconnected.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem. In the present invention, a conductive portion between a lead-out conductor of a coiled internal conductor and an external electrode is connected to a plurality of end faces and peripheral side faces of a multilayer chip inductor. Another object of the present invention is to provide a multilayer chip inductor having a high conduction area and high reliability of electrical connection between a coiled internal conductor and an external electrode.

[0008]

In order to achieve the above object, in a multilayer chip inductor according to the present invention, a ceramic laminate, a coil-shaped internal conductor formed inside the ceramic laminate, and the ceramic An end face of the laminate and an external electrode extending from the end face and formed on a peripheral side surface of the ceramic laminate near the end face, wherein the coil-shaped internal conductor is such that each end of the internal conductor is It is exposed on the end face and the peripheral side face of the ceramic laminate, and is electrically connected to the external electrode through this end.

Further, in the coil-shaped internal conductor, each end of the internal conductor is exposed to an end face and a plurality of peripheral side faces of the ceramic laminate, and is electrically connected to the external electrode through the end. I have. The coil-shaped internal conductor is formed on a laminated surface of the ceramic laminate.

The external electrode may be formed on an end face substantially perpendicular to the laminating direction of the ceramic laminate and a peripheral side surface near the end face, or may be formed on an end face substantially parallel to the laminating direction of the ceramic laminate and near the end face. Is formed on the peripheral side surface.

Thus, even if the thickness of the coiled internal conductor is small, the area where each end of the coiled internal conductor is exposed to the end face and the peripheral side face of the ceramic laminate can be increased.
The conductive area between each end of the coiled internal conductor and the external electrode can be increased.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 with 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, 45
b is different from the lead conductors 4 and 5 of the conventional example, and the same parts as those of the above-described conventional example are denoted by the same reference numerals, and detailed description is omitted. Note that the arrow X shown in FIG. 1 indicates the laminating direction of the green sheets.

As shown in FIG. 1, the multilayer chip inductor 41 has a coiled internal conductor 43 inside a ceramic laminate 42. External electrodes 6 and 7 are provided on the end surface of the ceramic laminate 42 and the peripheral side surface near the end surface extending from the end surface.
Are formed, and the lead conductors 44a, 44b,
45a and 45b are provided. More specifically, the lead conductors 44a and 45a are formed so as to conduct to the end face of the ceramic laminate 42, and the lead conductors 44b and 45b are formed to conduct to the peripheral side surface of the ceramic laminate 42.

As shown in FIG. 2, the ceramic laminate 42 is made of an insulating ceramic green sheet 4 such as a magnetic material.
6, 46, 46, 48, 12 to 19, 49, 46, 4
6 and 46 are obtained by laminating, pressing and sintering in order from the bottom.

The green sheet 46 includes a green sheet 4
Via holes 47 are provided at predetermined positions so as to be electrically connected to the lead conductors 44b and 45b and the external electrodes 6 and 7 formed at 8, 49. In via hole 47,
The lead conductors 45a and 45b are formed, and when the green sheets 48, 12 to 19 and 49 are laminated in order from the bottom, each end of the coil-shaped internal conductor 43 integrally formed with the internal conductors 25 to 32. Section.
One end of each of the lead conductors 44a and 45a is connected to the ceramic laminate 42.
Are exposed on both end faces substantially perpendicular to the laminating direction.

The green sheets 48 and 49 include the lead conductor 4.
4b and 45b are formed at one end of each surface, and via holes are provided at predetermined positions so as to be electrically connected to one ends of the internal conductors 25 and 32 formed on the green sheets 12 and 19. The lead conductors 44b and 45b are electrically connected to the respective ends of the coiled internal conductor 43 and are exposed on the peripheral side surface of the ceramic laminate 42.

By forming the external electrodes 6 and 7 on the end surface of the ceramic laminate 42 substantially perpendicular to the laminating direction and on the peripheral side surface near the end surface, a multilayer chip inductor 41 is obtained as shown in FIG.

The multilayer chip inductor 41 having the above configuration
The inner conductor 43 is electrically connected to the external electrodes 6 and 7 via the lead conductors 44 a and 45 a on the end face of the ceramic laminate 42, and is connected to the lead conductor 44 on the peripheral side surface of the ceramic laminate 42.
B and 45b conduct to the external electrodes 6 and 7.

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 with FIG. 1, the direction in which the external electrodes are formed differs by 90 ° with respect to the laminating direction of the green sheets. The same reference numerals are given and detailed description is omitted. In addition,
Arrow X shown in FIG. 4 indicates the direction in which the green sheets are stacked.

As shown in FIG. 4, the multilayer chip inductor 51 has a coiled internal conductor 53 inside a ceramic laminate 52, and has an end face of the ceramic laminate 52 and a ceramic laminate near the end face extending from the end face. External electrodes 56 and 57 are formed on the peripheral side surface of the reference numeral 52. Leading conductors 54a, 54b are provided at each end of the coiled internal conductor 53 so that the coiled internal conductor 53 and the external electrodes 56, 57 are conducted.
And lead conductors 55a and 55b, respectively. Specifically, the lead conductors 54a and 55a are formed so as to be electrically connected to the peripheral side surface of the ceramic laminate 52, and the lead conductors 54b and 55b are formed so as to be electrically connected to the end surface of the ceramic laminate 52.

As shown in FIG. 5, the ceramic laminate 52 is made of an insulating ceramic green sheet 4 such as a magnetic material.
6, 46, 46, 58, 13 to 19, 59, 46, 4
6 and 46 are obtained by laminating, pressing and sintering in order from the bottom.

The green sheets 58, 59 have less than one turn of internal conductors 60, 61 formed on their respective surfaces, and one end of each of the internal conductors 60, 61 is exposed on one side surface of the green sheets 58, 59. As the lead conductor 54
b, 55b are formed. Furthermore, the green sheet 58
Are provided with via holes at the ends of the internal conductors 60, and the green sheets 59 are provided with via holes at the ends of the internal conductors 61.
When 9, 59 are laminated, the inner conductors 60, 26 to 32,
61 are sequentially conducted through the respective via holes to form a coil-shaped internal conductor 53.

An external electrode 5 is provided on an end surface of the ceramic laminate 52 substantially parallel to the laminating direction and a peripheral side surface near the end surface.
By forming 6, 57, the multilayer chip inductor 51 is obtained.

The multilayer chip inductor 51 having the above configuration
Of the coil-shaped internal conductor 53 is connected to the external electrodes 56, 5
7 and to the external electrodes 56 and 57 via the lead conductors 54a and 55a on the peripheral side surface of the ceramic laminate 52.

The multilayer chip inductor according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention. 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 positions, and similarly, the lead conductors 44b and 45b are provided. It is more preferable to provide a plurality of end surfaces of the green sheets 48 and 49 to increase the conductive area with the external electrodes 6 and 7.

It is needless to say that the predetermined number of turns and the predetermined inductance of the coiled internal conductor can be obtained by appropriately increasing or decreasing the number of stacked green sheets.

[0027]

As described above, in the multilayer chip inductor according to the present invention, since each of the lead conductors of the coil-shaped internal conductor is exposed on the end face and the peripheral side face of the ceramic laminate and is electrically connected to the external electrodes, The area is increased, and the reliability of the electrical connection between each end of the coiled internal conductor and the external electrode can be increased.

Further, since the lead conductor is exposed on each of the end face and the peripheral side face of the ceramic laminate, that is, it is electrically connected to the external electrodes in directions different from each other, the circuit board on which the multilayer chip inductor is mounted is bent. Even if internal stress is generated in the multilayer chip inductor due to deformation or the like, the stress is usually in one direction, so either one of the end conductors of the multilayer chip inductor and the lead conductor on the peripheral side surface conducts with the external electrode. In other words, the reliability of the electrical connection between each end of the coiled internal conductor and the external electrode can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a multilayer chip inductor according to an embodiment of the present invention.

FIG. 2 is a perspective view of the multilayer chip inductor of FIG. 1 before stacking.

FIG. 3 is a perspective view of the multilayer chip inductor of FIG. 1;

FIG. 4 is a 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 stacking.

FIG. 6 is a 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 Laminated chip inductor 42 Ceramic laminate 43 Coiled internal conductor 44a, 44b, 45a, 45b Lead-out conductor 51 Laminated chip inductor 52 Ceramic laminate 53 Coiled internal conductor 54a, 54b, 55a, 55b Conductor 56, 57 External electrode X Stacking direction

Claims (5)

[Claims] 1. A ceramic laminate, a coil-shaped internal conductor formed inside the ceramic laminate, and an end face of the ceramic laminate and a peripheral side surface of the ceramic laminate extending from the end face and near the end face. An external electrode formed,
Wherein each end of the coil-shaped internal conductor is exposed to an end face and a peripheral side face of the ceramic laminate,
The multilayer chip inductor is electrically connected to the external electrode through the end. 2. The coil-shaped internal conductor is such that each end of the internal conductor is exposed to an end face and a plurality of peripheral side faces of the ceramic laminate, and is electrically connected to the external electrode via the end. The multilayer chip inductor according to claim 1, wherein 3. The multilayer chip inductor according to claim 1, wherein the coil-shaped internal conductor is formed on a lamination surface of the ceramic laminate. 4. The lamination according to claim 1, wherein the external electrode is formed on an end face substantially orthogonal to a lamination direction of the ceramic laminate and on a peripheral side surface near the end face. Type chip inductor. 5. The device according to claim 1, wherein the external electrode is formed on an end surface substantially parallel to a laminating direction of the ceramic laminate and a peripheral side surface near the end surface. Multilayer chip inductor.