JP3304798B2 - Electronic component and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component such as a chip inductor, a chip capacitor and an LC composite chip component, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Laid-Open No. 7-2403 is disclosed.
No. 34 is known.

Hereinafter, a conventional electronic component will be described with reference to the drawings, taking a chip inductor as an example.

FIG. 4A is a front view of a conventional chip inductor, and FIG. 4B is a sectional view of the same semi-finished product.

In FIGS. 4 (a) and 4 (b), reference numeral 1 denotes a laminated body formed by alternately laminating and sintering coil-forming conductors 2 and ferrite powder paste layers 3. Pores (not shown) on the surface of the laminate 1 are impregnated with a synthetic resin selected from a silicone resin and a phenol resin. Reference numeral 4 denotes an external electrode that is electrically connected to one end of the coil-forming conductor 2 on the opposite side of the laminate 1.

[0006] A method of manufacturing the conventional chip inductor configured as described above will be described below.

First, a coil-forming conductor 2 and a ferrite powder paste layer 3 are alternately laminated and integrally sintered to form a laminate 1.

Next, external electrodes 4 are formed on opposing side surfaces of the laminated body 1 so as to be electrically connected to the coil forming conductors 2.

Next, as shown in FIG. 5, the laminate 1 having the external electrodes 4 obtained in the previous step is placed in a beaker 5 in a mixed solution having a ratio of “silicone resin 2: gasoline 8”. And sealed in a desiccator 6 and a vacuum pump 8
After the vacuum impregnation is completed, the product is taken out of the beaker 5 and thoroughly washed with gasoline, then dried at a high temperature of about 100 ° C. for about 30 minutes to be cured.

[0010] Finally, a plating layer (not shown) is formed by electroplating on the external electrodes 4 of the laminate 1 obtained in the previous step to manufacture a chip inductor.

[0011]

However, in the above-mentioned conventional device, a mixture of a silicone resin and gasoline (hereinafter, referred to as a "mixture") is attached to the pores on the surface of the laminate 1. Thereafter, since the mixture is washed with gasoline before curing, the mixed solution once adhered to the laminate 1 elutes, and a portion where the mixed solution remains and a portion where the mixed solution does not remain are generated. Therefore, when the plating layer is formed by electroplating, However, there has been a problem that the infiltration of the electrolyte solution and the intrusion of moisture into the finished product cannot be completely prevented, and the electric characteristics deteriorate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electronic component and a method for manufacturing the same, which have improved electrical characteristics by preventing infiltration of an electrolytic solution or moisture.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for manufacturing a ceramic element comprising the steps of:
For the part electrode ,

[0014]

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Or

[0016]

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Is impregnated by dehydration condensation.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a ceramic body, a conductor on the inside or / and the outer periphery of the ceramic body, and external electrodes on both sides.
In the electronic component obtained, the fineness of the surface of the ceramic body is reduced.
Holes and the external electrodes ,

[0019]

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Or

[0021]

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Is impregnated by dehydration condensation.
According to a second aspect of the present invention, the ceramic body according to the first aspect is a ferrite sintered body.

According to a third aspect of the present invention, there is provided an electronic component in which a ceramic body having a conductor therein is formed, and external electrodes that are electrically connected to the conductor are formed on both side surfaces of the ceramic body. In the manufacturing method, after forming the external electrode,

[0024]

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Or

[0026]

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After being immersed in a solution containing and heat-treated, a plating layer is formed by electroplating so as to cover the external electrodes.

The structure and the manufacturing method described above have the function of preventing the electrolyte solution, water and the like from entering the ceramic body.

Hereinafter, an electronic component and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings, taking a chip inductor as an example.

FIG. 1 is a sectional view of a chip inductor according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a surface and pores (not shown) opened to the surface.

[0031]

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Or

[0033]

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Is a ceramic body made of a ferrite sintered body formed by dehydration condensation. Reference numerals 12 and 13 denote first and second internal conductors made of silver or the like provided alternately inside the ceramic body 11. 14 is provided between the first and second internal conductors 12 and 13 and is provided between the first and second internal conductors 12 and 13.
Is a connection via made of silver or the like for electrically connecting the internal conductors 12 and 13 with each other. 15 is a ceramic body 11
Of the first and second inner conductors 1
An external electrode made of silver or the like provided so as to be electrically connected to one of the electrodes 2 and 13. 16 is the external electrode 1
Reference numeral 17 denotes a plating layer made of nickel or the like provided so as to cover 5, and reference numeral 17 denotes a solder plating layer made of tin or the like provided so as to cover the plating layer 16.

Here, the metal atoms on the surface of the ceramic body 11 made of metal oxide are hydroxides at room temperature, and the hydroxyl groups on the surface and the organosilicon compound of the present invention are dehydrated and condensed to form a ceramic. Since a water-repellent film is formed on the surface of the element body 11 and the pores inside and on the surface of the ceramic element 11 are very small, an aqueous solution such as a plating solution is removed from the surface of the water-repellent ceramic element 11. Cannot penetrate, does not affect the inside of the ceramic body 11, and does not form the above-mentioned hydroxyl group on the surface of a noble metal such as silver or Pd used for the external electrode 15.
No. 5 does not react with the organosilicon compound and does not become water repellent, so that good contact with the plating solution is maintained, and a plating film of nickel, solder or the like is formed stably.

Since the excess organosilicon compound does not react with the surface and evaporates during the heat treatment process, a washing step is not required as in the case of the conventional resin immersion, and the surface treatment with good reproducibility is performed. be able to.

A method of manufacturing the chip inductor having the above-described structure according to the embodiment of the present invention will be described below.

2 and 3 are process diagrams showing a method for manufacturing a chip inductor according to an embodiment of the present invention.

First, as shown in FIG. 2A, a plurality of spiral first and second coil conductor patterns 21 and 22 are formed by printing a silver-based thick film paste on the upper surface and drying the paste.
The first and second green sheets 23 and 24 having a through hole 25 are provided with a through hole 25 corresponding to one end of the first and second coil conductor patterns 21 and 22 of the first and second green sheets. About 70 so that the first and second coil conductor patterns 21 and 22 of the first and second green sheets 23 and 24 are electrically connected via the green sheet 26 of FIG.
Pressure and laminate at kg / cm ² .

Next, as shown in FIG. 2 (b), the fourth and fifth green sheets are respectively provided on the surfaces of the first and second green sheets 23 and 24 facing the third green sheet 26. After laminating 27 and 28, a pressure is applied at about 70 kg / cm ² to form a laminate 29.

Next, as shown in FIG. 2C, the laminate 29 is cut by Thomson cutting or the like so that a part of the first and second coil conductor patterns 21 (22) is exposed facing the side surface. After cutting into individual pieces, baking at about 900 ° C for about 3 hours,
A chip-shaped ferrite sintered body 30 is obtained.

Next, as shown in FIG. 2D, the first and second exposed ferrite sintered bodies 30 are partially exposed from the side surfaces.
A thick film conductor paste such as silver is applied to the opposing side surfaces of the ferrite sintered body 30 by a Paloma method or the like so as to be electrically connected to the coil conductor patterns 21 (22).
The external electrodes 31 are formed by baking at about 10 minutes for about 10 minutes to obtain the chip inductor 32.

Next, as shown in FIG.

[0044]

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Or

[0046]

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The coating liquid 33 mixed with isopropyl alcohol as a diluent and adjusted so as to be about 1% by weight is placed in a container 34, and the chip inductor 32 obtained in the previous step is immersed therein for about 10 minutes. . Here, the immersion may be performed in a vacuum atmosphere as needed. Also,
The diluent may be an organic solvent such as ethanol or toluene other than isopropyl alcohol, and is not limited thereto.

Next, as shown in FIG. 3B, the chip inductor 32 is taken out and dried at a high temperature of about 160 ° C. for about 20 minutes.

Finally, nickel plating is applied so as to cover the external electrodes 31 of the chip inductor 32 obtained in the previous step, and further, solder plating such as tin is applied so as to cover the nickel plating. It is for manufacturing inductors.

Table 1 shows that the chip inductor 36 manufactured according to the above-described embodiment and the chip inductor manufactured according to the conventional example are subjected to a pressure cooker test (temperature 121 ° C., humidity 100%, pressure 2 atm) for 100 hours. The change in inductance value at a subsequent frequency of 100 MHz is examined and compared. Each of 1,000 pieces was tested, and the occurrence rate of those whose properties changed by 50% or more before and after the test was shown.

[0051]

[Table 1]

As is clear from Table 1, the chip inductor manufactured according to the present embodiment does not penetrate moisture because the protective film is formed evenly on the ceramic surface and the pores opened on the surface. The change in the inductance value after the test is small, which significantly improves the electrical reliability of the chip inductor.

(Table 2) shows the chip inductor 36 manufactured according to the above-described embodiment, the chip inductor manufactured according to the conventional example, the chip inductor manufactured according to the conventional example, the chip inductor manufactured according to the conventional example, and the laminate whose surface was not cleaned before curing. These are the results of comparative observation of the plating state on the external electrode in the above three types of samples. Each 1,000 samples were observed, and the rate of occurrence of samples having no plating film formed thereon was shown.

[0054]

[Table 2]

As is clear from Table 2, the plating layer could not be formed on the external electrodes in the conventional chip inductor in which the mixture was not removed by cleaning the surface of the laminated body. In all of the chip inductors manufactured according to the above embodiments, plated films could be formed. The intended product is obtained without the need for washing.

The electronic component to which the present invention is applied is not limited to a chip inductor, but may be anything as long as the ceramic surface is exposed.

[0057]

As described above, the present invention provides an electrolytic solution, water and the like by forming a film obtained by dehydrating and condensing an organosilicon compound on the surface of a ceramic body and on pores opened to the surface. To prevent intrusion into the inside of the ceramic body, improve the electrical characteristics, and form a protective film on the ceramic body but not on the external electrodes. Since it is not necessary to wash and remove the mixed solution once adhered and then harden in order to electroplate on the external electrode after formation, there is no variation in the presence or absence of formation of a protective film, so it is a product with excellent electrolyte resistance and moisture resistance Further, it is possible to provide an electronic component and a method of manufacturing the same, which can reduce the number of cleaning steps and the amount of cleaning liquid used.

[Brief description of the drawings]

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

[Fig. 2]

[Fig. 3]

4A is a front view of a conventional chip inductor, and FIG.

[Fig. 5]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ceramic body 12 1st internal conductor 13 2nd internal conductor 15 External electrode

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Hasegawa 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-8-111348 (JP, A) JP-A-5-243076 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4 / 40 C04B 41/84 H01F 17/00-17/08 H01F 41/00-41/12

Claims (3)

(57) [Claims] 1. A ceramic body and a conductor inside and / or at an outer peripheral portion of the ceramic body, and outer conductors on both side surfaces.
An electronic component comprising a partial electrode, wherein pores on the surface of the ceramic body and the external electrode are impregnated with (Chem. 1) or (Chem. 2) by dehydration condensation. Embedded image Embedded image 2. The electronic component according to claim 1, wherein the ceramic body is a ferrite sintered body. 3. A method for manufacturing an electronic component, comprising: forming a ceramic body having a conductor inside; and forming external electrodes on both sides of the ceramic body to conduct with the conductor. After formation, Or A method for producing an electronic component, comprising: immersing in a solution containing, and heat-treating, and then forming a plating layer by electroplating so as to cover the external electrodes.