JPH05152130A - Composite inductor and its manufacture - Google Patents

Abstract

PURPOSE:To realize a composite inductor wherein it is small-sized, its height is low, it is excellent in an automatic mounting property and it is rich in mass productivity in the composite inductor which is used as a noise filter in a high- frequency circuit for various kinds of electric apparatuses. CONSTITUTION:The titled inductor is constituted of the following: a strip-shaped ceramic substrate 10; a magnetic-substance layer 40 formed on the ceramic substrate 10; a plurality of conductor patterns 30 which have been formed inside a magnetic-substance layer 40 and which are independent with each other; and a plurality of edge electrodes 20 which are formed on edges of the ceramic substrate 10 and which are connected to the conductor patterns 30. Thereby, since the title inductor is constituted mainly of a thick film and the edge electrodes 20 formed on side faces of the ceramic substrate 10 can be soldered directly to a circuit board, it is small-sized, its height is low and it is excellent in a mounting property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite inductor mainly used as a noise filter for high frequency circuits and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, composite inductors have been widely used as high frequency noise absorbing elements for high speed digital circuits.

A conventional composite inductor will be described below. FIG. 14 shows an external perspective view of a conventional composite inductor, and FIG. 15 shows an exploded perspective view thereof. As shown in the same figure, a conventional composite inductor includes a ceramic sheet 2 made of a magnetic material in which four electrode lines 1 are formed in parallel on one surface, and a magnetic material in which no electrode line 1 is formed. A laminated body 4 in which a ceramic sheet 3 for covering front and back surfaces made of a material is laminated on each other and integrally fired.
Is equipped with. Further, external electrodes 5 that are electrically connected to the exposed edges of the electrode lines 1 are formed on both side surfaces of the laminated body 4.

[0004]

However, the above-mentioned conventional composite inductor has the following major problems in terms of product shape, noise absorption performance and manufacturing.

That is, in the conventional case, since the inductor has a large element size, it cannot be used in a device which is thin and requires miniaturization. Further, since the external electrode 5 has high adhesion to the laminated body 4, it is necessary to perform soldering on a circuit board under a strict temperature profile. In addition, since the magnetic ceramic itself has low mechanical strength, it is not possible to make the element thickness thin, and it is not possible to manufacture by a manufacturing method that breaks a sheet-shaped sintered body into individual pieces by chocolate break, and the mass productivity is low. Become.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a composite inductor having excellent mountability and mass productivity which cannot be realized by the conventional composite inductor.

[0007]

In order to achieve this object, a composite inductor of the present invention comprises a strip-shaped ceramic substrate, a magnetic layer formed on the ceramic substrate, and a magnetic layer inside the magnetic layer. It has a structure including a plurality of independent conductor patterns formed and a plurality of end face electrodes connected corresponding to each of the conductor patterns formed on the end face of the ceramic substrate.

[0008]

With this structure, since the end surface electrodes provided on the side surface of the ceramic substrate can be directly soldered to the circuit board, it can be mounted with a low profile and high density, and the thick film is the main structure, which facilitates the manufacture. With high mass productivity. Therefore, it is possible to provide a thick film composite inductor having excellent mountability and mass productivity that cannot be realized by the conventional composite inductor.

[0009]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a composite inductor according to a first embodiment of the present invention, FIG. 2 is an external perspective view thereof, and FIG. 3 is an equivalent circuit diagram thereof. 4 is a plan view showing the first half step of the manufacturing method and FIG. 5 is a plan view showing the second half step. 1, FIG. 2, FIG. 4, and FIG. 5, 10 is a ceramic substrate, 11 is an alumina-based sheet-shaped ceramic substrate, 12 is a round hole provided in the sheet-shaped ceramic substrate 11, 20 is an end face electrode, and 30 is a conductor pattern. , 40a and 40b are magnetic layers, 50 is a protective coating layer, 61 is a primary dividing groove, and 62 is a secondary dividing groove.

A method of manufacturing the composite inductor having the above-described structure will be described with reference to the drawings. First, as shown in FIG. 4 (a), a sheet-shaped ceramic substrate 11 is prepared in which round holes 12 having a diameter of 0.4 mm are provided at equal pitches along the secondary dividing groove 62. A plurality of end face electrodes 20 were formed by through-hole printing a palladium-based thick film conductor paste with a screen printer and baking at 850 ° C. for 1 hour.

Next, as shown in FIG. 4 (b), NiZn
After screen-printing a magnetic paste containing a system ferrite as a main component on one surface of the sheet-shaped ceramic substrate 11, a plurality of independent pastes connected to the end face electrodes 20 are formed thereon as shown in FIG. 4C. 800 to 10 after printing the conductor pattern 30 using a silver-based thick film conductor paste
It was formed together with the magnetic layer 40a by firing at a temperature of 00 ° C. Further, as shown in FIG. 5A, a magnetic paste was printed so as to cover the conductor pattern 30 and fired similarly to form a magnetic layer 40b. In addition,
The magnetic layers 40a and 40b become the integrated magnetic layer 40 by firing.

Finally, as shown in FIG. 5 (b), after applying an epoxy type protective coating layer 50 for the purpose of preventing moisture in the composite inductor, as shown in FIG. 5 (c), the primary dividing groove 6 is formed.
The composite inductor was completed by dividing it into a rod shape along 1 and further dividing into individual pieces along the secondary dividing groove 62.

A typical example of frequency-impedance characteristics of one element of the composite inductor according to this embodiment is shown in FIG. As is clear from the figure, the composite inductor according to the present invention has a frequency of 200 MHz and a conventional inductor of about 100 Ω.
It has an extra impedance and has excellent performance as a noise absorbing element in high frequency circuits.

As described above, according to this embodiment, the magnetic layer 40 formed on the strip-shaped ceramic substrate 10 and the plurality of independent conductor patterns 30 formed inside the magnetic layer 40. By including the plurality of end face electrodes 20 connected to the conductor pattern 30 formed on the end face of the ceramic substrate 10, it is possible to realize a composite inductor having excellent noise removal property and mountability. Especially, since the end face electrode 20 is formed in the recess,
Good reflow solderability due to alignment effect,
Further, a highly reliable composite inductor having high adhesion strength of the end face electrode 20 can be obtained. In this embodiment, the end face electrode 20
Although it is provided in the concave portion, the solderability is good even if it is provided in the convex portion, and the unevenness of the end face is effective for the solderability.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a partially cutaway perspective view of a composite inductor showing a second embodiment of the present invention. In FIG. 7, 10 is a ceramic substrate, 20 is an end face electrode, 30 is a semiconductor pattern, and 41 is a separated magnetic layer, which is similar to the configuration of FIG. The difference from the configuration of FIG. 2 is that the magnetic layer 41 is formed separately on the ceramic substrate 10 corresponding to each conductor pattern 30, and a plurality of magnetically independent inductors are configured.

The method of manufacturing the composite inductor configured as described above can be obtained by the same procedure as that of the first embodiment except that the formation pattern of the magnetic layer 41 is an independent pattern.

Since the composite inductor thus obtained is magnetically independent by being separated from each other, there is no signal interference between the adjacent inductors and the distance between the adjacent terminals can be made small. Can be compactly integrated.

As described above, the strip-shaped ceramic substrate 1
0, a plurality of magnetic layers 41 each having an independent conductor pattern 30 provided therein and separated magnetically independently, and a conductor pattern 30 formed on the end surface of the ceramic substrate 10.
With the structure including the plurality of end surface electrodes 20 connected to each other, it is possible to realize a small-sized composite inductor having excellent high-frequency characteristics without interference between the combined inductors.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 8 is an external perspective view of a composite inductor showing a third embodiment of the present invention.
Shows an exploded perspective view thereof. 10 to 12 are plan views showing the manufacturing method of the present invention. 8-12,
13 is a ceramic substrate, 21 is an end face electrode, 31a and 31b are conductor patterns, 42, 42a, 42b, 42c.
Is a magnetic layer, 70, 70a, 70b and 70c are non-magnetic layers, 11 is a sheet-like ceramic substrate, 61 is a primary dividing groove, and 62 is a secondary dividing groove.

A method of manufacturing the composite inductor having the above-described structure will be described with reference to the first half process diagram of FIG. 10, the middle process diagram of FIG. 11, and the second half process diagram of FIG. Figure 1
The sheet-shaped ceramic substrate 11 in which the primary divided grooves 61 and the secondary divided grooves 62 are processed vertically and horizontally so that one piece after division as shown in FIG. 0 (a) becomes a strip-shaped ceramic substrate 13 of 2.5 × 7 mm. As shown in FIG. 10 (b), a crystallized glass paste is screen-printed on one surface of the above and baked at 850 ° C. for 1 hour to form the nonmagnetic layer 70a. Next, as shown in FIG. 10C, a magnetic paste containing NiZn-based ferrite as a main component is screen-printed to form a magnetic layer 42a. Next, as shown in FIG. 11A, a plurality of independent conductor patterns 31a, which are a part of the coil pattern, were formed by printing using a silver palladium-based thick film conductor paste. Furthermore, FIG.
As shown in (b), a via hole portion of the conductor pattern 31a is opened and a magnetic paste is printed so as to cover the entire surface to form a magnetic layer 42b. Then, as shown in FIG. Conductor pattern 31b which is a coil pattern
Was similarly printed using a silver palladium thick film paste. Subsequently, as shown in FIG. 12A, a magnetic layer 42c covering the conductor pattern 31b and a non-magnetic layer 70c are formed by printing, followed by firing at a temperature of 800 ° C. to 1200 ° C. for 1 hour, and then, FIG. As shown in (1), it was divided into bars along the primary dividing groove 61. Finally, as shown in FIG. 12C, the end face electrodes 21 connected to the conductor patterns 31a and 31b are formed by baking a silver palladium-based thick film conductor, and divided along the secondary dividing groove 62. To complete the composite inductor.

The composite inductor configured as described above and the manufacturing method thereof can be obtained by the same procedure as that of the second embodiment except that the magnetic layer 42 is independently formed via the non-magnetic layer 70.

In the composite inductor thus obtained, a plurality of inductors having no signal interference between terminals can be compactly integrated as in the second embodiment, and a non-magnetic layer 70 is formed. Therefore, the surface of the composite inductor element is smooth, and it is easy to mount automatically.

As described above, the strip-shaped ceramic substrate 1
3 has a plurality of independent conductor patterns 31 provided therein,
In addition, the magnetic layer 42, the non-magnetic layer 70, and the plurality of end face electrodes 21 connected to the conductor pattern 31 formed on the end face of the ceramic substrate 13 are magnetically and independently separated from each other. Combined inductors It is possible to realize a small-sized composite inductor with excellent high-frequency characteristics and excellent mountability without mutual interference.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 13 is an exploded perspective view of a composite inductor showing the structure of the fourth embodiment of the present invention. In the figure, 10 is a ceramic substrate, 20 is an end face electrode, 32a and 32b are conductor patterns, 43
a, 43b, 43c are magnetic layers, 50 is a protective coating layer,
80 indicates an inorganic adhesive layer, respectively.

The composite inductor of Example 4 was provided with an epoxy-based protective coating layer 50 for the purpose of preventing moisture.
The procedure was the same as in Example 2 and Example 3 except that the inorganic adhesive layer 80 was formed for the purpose of firmly adhering the magnetic layer 43a to the ceramic substrate 10. By providing this inorganic adhesive layer 80, the strength of the composite inductor was enhanced.

In the first to fourth embodiments, the silver-palladium-based paste was used as the thick-film conductor material and all were fired in air. However, the copper-based paste was used to fire in a non-oxidizing atmosphere. May be. Further, in the above embodiment,
Although the magnetic layer is formed on only one side of the substrate, it goes without saying that it may be formed on both sides of the ceramic substrate. Furthermore, in the examples, the conductor pattern and the magnetic layer were all provided by screen-printing these thick film pastes,
It may be formed by another method such as bonding a green sheet.

[0027]

As described above, the present invention includes a strip-shaped ceramic substrate, a magnetic layer formed on the ceramic substrate, and a plurality of independent conductor patterns formed inside the magnetic layer. , A structure consisting of a plurality of end face electrodes connected corresponding to each of the conductor patterns formed on the end face of the ceramic substrate is mainly used for thick film, and direct soldering on the end face is possible. Therefore, it is possible to realize a composite inductor having a small size, a low profile, excellent mountability, and mass productivity that cannot be realized by the conventional composite inductor.

[Brief description of drawings]

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

FIG. 2 is an external perspective view of the composite inductor.

FIG. 3 is an equivalent circuit diagram of the same.

4 (a), (b) and (c) are plan views illustrating the first half step of the method for manufacturing the same composite inductor.

5A, 5B, and 5C are plan views illustrating the latter half of the process.

FIG. 6 is a frequency characteristic diagram of the composite inductor according to the first embodiment of the present invention.

FIG. 7 is a partially cutaway perspective view of a composite inductor according to a second embodiment of the present invention.

FIG. 8 is an external perspective view of a composite inductor according to a third embodiment of the present invention.

FIG. 9 is an exploded perspective view of the composite inductor.

10 (a), (b) and (c) are plan views illustrating a first half step of the manufacturing method of the same composite inductor.

11 (a), (b), (c) are plan views for explaining the mid-step.

12A, 12B, and 12C are plan views illustrating the latter half of the process.

FIG. 13 is an exploded perspective view of a composite inductor according to a fourth embodiment of the present invention.

FIG. 14 is an external perspective view of a conventional composite inductor.

FIG. 15 is an exploded perspective view of a conventional composite inductor

[Explanation of symbols]

10, 13 Ceramic substrate 11 Sheet-shaped ceramic substrate 12 Round hole 20,21 End surface electrode 30, 31a, 31b, 32a, 32b Conductor pattern 40, 40a, 40b, 41, 42, 42a, 42b,
42c, 43a, 43b, 43c Magnetic material layer 61 Primary dividing groove 62 Secondary dividing groove 70, 70a, 70b, 70c Non-magnetic material layer 80 Inorganic adhesive layer

Claims (9)

[Claims] 1. A strip-shaped ceramic substrate, a magnetic layer formed on the ceramic substrate, a plurality of independent conductor patterns provided in the magnetic layer, and independent conductor patterns formed on the end face of the ceramic substrate. And a plurality of end face electrodes connected corresponding to each of the formed conductor patterns. 2. The composite inductor according to claim 1, wherein the magnetic layer is separated corresponding to each conductor pattern. 3. The composite inductor according to claim 2, wherein a non-magnetic material is provided in the separated portion of the magnetic material layer. 4. The composite inductor according to claim 1, wherein the ceramic substrate is provided with regular concavities and convexities on the end faces thereof, and the end face electrodes are formed on the concave or convex portions. 5. The composite inductor according to claim 1, wherein the magnetic layer is formed on the ceramic substrate via an inorganic adhesive layer. 6. A magnetic layer having a conductor pattern provided therein is formed on a sheet-shaped ceramic substrate having a primary dividing groove and a secondary dividing groove at predetermined positions, and then divided along the primary dividing groove. 2. The method of manufacturing a composite inductor according to claim 1, wherein the ceramic substrate is in the form of a strip, and an end face electrode connected to the conductor pattern is formed on an end face of the ceramic substrate, and then divided along the secondary dividing groove. 7. The method of manufacturing a composite inductor according to claim 6, wherein in forming the magnetic layer, the magnetic layer separated corresponding to each conductor pattern is formed. 8. The method of manufacturing a composite inductor according to claim 7, wherein a non-magnetic material layer is formed in a separated portion of the magnetic material layer before or after the magnetic material layer is formed on the sheet-shaped ceramic substrate. 9. The end face electrode is formed by using a sheet-shaped ceramic substrate in which the end face electrode is formed in advance on the inner wall of regularly provided holes, and the end face electrode and the conductor pattern are connected to each other. A method for manufacturing the described composite inductor.