JPH10208907A - Electronic device and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device in which possibility of moisture intrusion through the end part of the electrode is eliminated by coating the end part of the electrode with resin. SOLUTION: Outer electrodes 3 are formed on the opposite end faces of a varistor element 1 comprising an alternate laminate of a ceramic sheet 1a and an inner electrode 2. The porous surface in the varistor element 1 is then coated with Si resin while filling the pores and an outer surface insulation layer 31 is formed to cover the inner surface insulation layer 30, the outer surface of the varistor element 1 and the end part of the outer electrode 3 thus completing a multilayer varistor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic component such as a multilayer varistor and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional electronic component has at least a pair of electrodes on the outer surface of a body, and impregnates only the surface of the body on which no electrodes are formed with resin.

[0003]

According to this structure, although the moisture resistance is improved by the resin impregnated in the element body, there is a problem that moisture and the like infiltrate from the end of the electrode to cause deterioration of characteristics. I was

Accordingly, an object of the present invention is to provide an electronic component capable of preventing the penetration of moisture or the like from an electrode end by coating the electrode end with an insulating layer.

[0005]

In order to achieve the above object, an electronic component according to the present invention comprises: a body having a curved end;
At least one pair of electrodes formed at predetermined intervals on the outer surface of the end of the element body, and an insulating layer provided so as to cover a part of the element body surface where the electrode is not formed and an end of the electrode. At least a part of the insulating layer is impregnated on the inner surface of the element body, and the insulating layer on the outer surface prevents peeling of the electrode end, preventing intrusion of moisture and the like from the electrode end. Can be prevented.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a body having a curved end portion and at least a pair of body members formed at predetermined intervals on the outer surface of the body end portion. An electrode, and an insulating layer provided so as to cover a portion of the element body surface where the electrode is not formed and an end of the electrode, and at least a part of the insulating layer is impregnated on an inner surface of the element body. In addition, the insulating layer impregnated on the inner surface can prevent the deterioration of the moisture resistance property, and the insulating layer on the outer surface can also prevent peeling of the electrode end.

According to a second aspect of the present invention, there is provided the electronic component according to the first aspect, wherein the insulating layer is formed by using at least one of a metal alkoxide and a resin. In addition to preventing deterioration, the insulating layer on the outer surface can also prevent peeling of the electrode end.

According to a third aspect of the present invention, the insulating layer is formed using a metal alkoxide.
2. The electronic component according to claim 1, wherein the electronic component has at least one metal selected from silicon, titanium, aluminum, zirconium, yttrium, and magnesium. In addition, the metal alkoxide on the outer surface can prevent peeling of the electrode end.

According to a fourth aspect of the present invention, the insulating layer is formed using a resin, and the resin is at least one of a silicon resin, an epoxy resin, an acrylic resin, a polybutadiene resin, and a phenol resin. The electronic component according to claim 1, wherein the number of types is equal to or more than one, wherein the resin impregnated on the inner surface can prevent the moisture resistance property from deteriorating, and the resin on the outer surface can also prevent peeling of the electrode end.

The invention according to claim 5 is the electronic component according to claim 1, wherein the thickness of the insulating layer impregnated on the inner surface of the element body is 10 μm or more. Therefore, moisture resistance can be ensured.

According to a sixth aspect of the present invention, there is provided the electronic component according to the first aspect, wherein the thickness of the insulating layer on the outer surface of the element body is smaller than the maximum thickness of the electrode adjacent to the insulating layer. And electronic components can be easily mounted.

According to a seventh aspect of the present invention, there is provided an element having a curved end portion, at least one pair of electrodes formed at predetermined intervals on an outer surface of the end portion of the element body, An insulating layer provided on at least a portion of the surface where no electrodes are formed,
The outer surface of the element body is a glossy electronic component, and has a glossy surface. Therefore, when an electronic component is selected, it can be easily determined whether or not it is a completed product.

The invention according to claim 8 is a step of forming at least a pair of electrodes at predetermined intervals on the outer surface of the end of the element having a curved end, and then forming the outer surface of the element. A step of contacting the impregnating liquid containing at least an organic substance to coat the outer surface of the element body with the impregnating liquid, and a step of removing a part of the impregnating liquid covering the outer surface of the element body, and then, A method of manufacturing an electronic component having a step of curing an organic substance and a step of polishing and removing the cured organic substance on the outer surface of the electrode of the element afterwards, wherein an insulating layer is formed on the outer surface as well as the surface of the element. Therefore, it is possible to obtain an electronic component in which exfoliation of the end of the electrode is prevented in addition to deterioration of the moisture resistance.

According to a ninth aspect of the present invention, there is provided the method of manufacturing an electronic component according to the eighth aspect, wherein the step of contacting the element body with the impregnating liquid is repeated a plurality of times, wherein the organic substance is sufficiently impregnated inside the element body. Therefore, an electronic component having more excellent moisture resistance can be obtained.

According to a tenth aspect of the present invention, there is provided a method of manufacturing an electronic component according to the eighth aspect, wherein an organic material containing at least one of a metal alkoxide and a resin is used. It is possible to obtain an electronic component in which peeling of the end of the electrode is prevented.

[0016] The invention according to claim 11 includes a metal alkoxide as an organic substance, wherein the metal alkoxide is at least one or more of silicon, titanium, aluminum, zirconium, yttrium, and magnesium. The electronic component can be obtained in which not only the deterioration of the moisture resistance property but also the peeling of the end of the electrode is prevented.

According to a twelfth aspect of the present invention, a resin is contained as an organic substance, and the resin is at least one or more of a silicone resin, an epoxy resin, an acrylic resin, a polybutadiene resin, and a phenol resin. According to the electronic component manufacturing method of the eighth aspect, it is possible to obtain an electronic component in which not only the end portions of the electrodes are prevented from peeling off in addition to the deterioration of the moisture resistance property.

According to a thirteenth aspect of the present invention, there is provided the electronic component manufacturing method according to the eighth aspect, wherein the element body is pressurized in contact with the impregnating liquid, and the impregnating liquid is easily impregnated into the element body. be able to.

According to a fourteenth aspect of the present invention, the organic substance on the outer surface of the element body is removed by at least one of centrifugation, washing with a liquid in which the organic substance is soluble, and contact with a powder that does not react with the impregnating liquid. The method for producing an electronic component according to claim 8, wherein the impregnating liquid can be easily impregnated into the ceramic body.

[0020] The invention according to claim 15 is characterized in that S
at least one of iO ₂ , ZrO ₂ , Al ₂ O ₃ , and MgO
The method for producing an electronic component according to claim 14, wherein the method includes using one containing more than one kind, and unnecessary organic substances can be easily removed.

According to a sixteenth aspect of the present invention, there is provided the electronic component manufacturing method according to the eighth aspect, wherein the polishing step is performed by moving a container containing at least the element body and the liquid, and does not hinder the subsequent steps. Organic substances on the electrode surface can be removed to a certain extent.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking a laminated varistor as an example.

(Embodiment 1) FIG. 1 is a cross-sectional view of a laminated varistor according to the present embodiment, FIG. 2 is a manufacturing process diagram of the laminated varistor according to the present embodiment, and FIG. FIG. 4 is a cross-sectional view of the varistor element after the centrifugation step, FIG. 5 is a cross-sectional view of the varistor element after immersion in toluene, FIG. 6 is a cross-sectional view of the varistor element after curing of Si resin, and FIG. It is a cross-sectional view of a varistor element,
Reference numeral 1 denotes a varistor element having a curved end face, and a plurality of internal electrodes 2 mainly containing Ni are provided inside. These internal electrodes 2 are alternately drawn to both end faces of the varistor element 1, and are electrically connected to the external electrodes 3 at both end faces. The external electrode 3 has at least a double structure. The inner layer 3a has Ni as a main component, and the outer layer 3b has Ag as a main component. Further, the ceramic sheet 1a between the internal electrodes 2 and outside thereof has SrTiO ₃ as a main component,
It contains Nb ₂ O ₅ , SiO _{2 and the} like as subcomponents. 3
Numeral 0 is an inner surface insulating layer formed by covering or filling the pore surface inside the varistor element 1 with Si resin. Reference numeral 31 denotes an outer surface insulating layer which covers the end of the external electrode 3 and is formed of Si resin. On the surface of the external electrode 3, a plating layer 4 made of Ni plating 4a and solder plating 4b is formed.

As shown in FIG. 2, the ceramic sheet 1a
Is formed by mixing, calcining, pulverizing, slurrying, and sheet forming the raw materials as shown by (11) in FIG.
Next, the ceramic sheet 1a and the internal electrode 2 are laminated (12), and cut (13), de-built (14),
Chamfer (15) and make the ends curved. Next, the inner layer 3a of the external electrode 3 is applied (16), and 1200 to 1300
At 17 ° C., and then the outer layer 3b is applied (1).
8) and heated at 800 to 850 ° C. for re-oxidation (1
9). Next, the completely dried varistor element 1 was immersed in a Si varnish containing 75% of toluene as a solvent (2).
0), the varistor element 1 is impregnated with Si varnish.

Thereafter, while the varistor element 1 is immersed in the Si varnish, the pressure is increased to ⁶ to 1500 kg / cm ² (21).
In order to further impregnate the varistor element 1 with the i-varnish, the varistor 1 is kept at, for example, 2 minutes and then returned to the atmospheric pressure where the laminated varistor is used. The varistor element 1 at this time is shown in FIG.
As shown in (1), the entire surface is thickly covered with the Si varnish 5, and the inside of the external electrode 3 and the inside of the varistor element 1 are also impregnated with the Si varnish 5. The pressing force at this time is determined by the density of the varistor element 1. In other words, the varistor element 1 having a higher density has a higher pressing force to facilitate impregnation. For example, in the case of a varistor element containing ZnO as a main component, the pressure is increased to 500 to 1500 kg / cm ² because of its high density. After that, the varistor element 1 is taken out from the Si varnish, placed in a metal net basket (or net or the like), and set in, for example, a centrifuge having an inner diameter of 60 cm.
Operating at 0 to 1500 r / min (22), unnecessary Si adhered to the outer surface of the varistor element 1 as shown in FIG.
The varnish 5 is roughly removed. Further, the metal net basket was immersed in toluene and vibrated for 5 to 60 seconds, and then taken out (23).
As shown in (1), the Si varnish adhering to the outer surfaces of the varistor element 1 and the external electrode 3 is removed. Also, instead of being immersed in toluene, the varistor element 1 is taken out of a metal mesh basket and is a powder SiO 2 which does not react with the Si varnish 5.
_{After the} powder ₂ is brought into contact with the varistor element 1 and unnecessary Si varnish 5 on the outer surface of the varistor element 1 is sucked into the SiO ₂ powder, the varistor element 1 may be separated using a sieve or the like. By the above method, the varistor element 1
Unnecessary Si varnish 5 on the surface is removed. After that, the varistor elements 1 are arranged on a metal net, and the temperature (about 125 to 200
6C) for heating the Si resin (24), and FIG.
A varistor element 1 as shown in FIG. With this heating,
S impregnated inside the varistor element 1 and the external electrode 3
Part of the i-resin precipitates. Thereafter, the varistor element 1, an abrasive made of SiC, and water are put in a container made of, for example, polyethylene and sealed, and the surface is polished by moving it by a mechanical method such as rotation or vibration (25), and shown in FIG. As described above, the Si resin on the surface of the external electrode 3 is removed to such an extent that the subsequent steps such as plating are not affected. This surface polishing (2
According to 5), the mechanical stress applied to the end surface of the varistor element 1 and the adhesive strength with the cured Si resin are superior to the ceramic body compared to the external electrode 3, so the Si resin on the external electrode 3 is selected. Can be removed. At this time, the Si resin remains on the inner surface of the external electrode 3, but this Si resin remains.
The electrical connection of the external electrodes 3 is not hindered by the resin. Further, the resin on the inner surface of the external electrode 3 can prevent the plating solution from entering the inside of the external electrode 3 in the subsequent plating (26).

Next, the surface of the external electrode 3 of the varistor element 1 is plated (26) to obtain a laminated varistor as shown in FIG.

As described above, Si inside the varistor element 1
By forming the inner surface insulating layer 30 impregnated with the resin, excellent moisture resistance is obtained, and by forming the outer surface insulating layer 31, exfoliation of the end of the external electrode 3 does not occur. It is possible to obtain a laminated varistor that does not affect the subsequent steps such as plating (26).

Here, the features of the laminated varistor and the manufacturing method according to the present embodiment will be described below. (1) As shown in FIG. 1, the outer surface insulating layer 31 is formed so as to cover the end of the external electrode 3 formed so as to cover the side surface of the varistor element 1, so that the external electrode 3 and the varistor element 1 A plating solution from the boundary to the inside of the varistor element 1;
Infiltration of moisture and the like can be further prevented. (2) Since the outer surface insulating layer 31 and the inner surface insulating layer 30 have luster, it is determined whether the inner surface insulating layer 30 and the outer surface insulating layer 31 have been formed by checking the gloss of the surface of the laminated varistor. Can be visually judged, and sorting can be easily performed. (3) S for forming the outer surface insulating layer 31 and the inner surface insulating layer 30
Although i resin was used, any resin may be used as long as it has heat resistance, high insulation, high water repellency, and low water absorption after curing.
In addition to the resin, there are an epoxy resin, an acrylic resin, a polybutadiene resin, a phenol resin and the like, and one or more of these may be used.

Instead of the resin or by mixing with the resin, silicon, titanium, aluminum, zirconium,
At least one selected from yttrium and magnesium
Similar effects can be obtained by using more than two kinds of metal alkoxides.

When a metal alkoxide is used, an impregnating liquid is prepared using a solvent capable of dissolving the metal alkoxide such as alcohol. (4) The thickness of the inner surface insulating layer 30 is desirably as large as possible without affecting the characteristics as a laminated varistor.
It is desirable that the thickness be 10 μm or more where the thickness is thinnest. This can be adjusted by selecting the viscosity, solvent ratio, and pressure of the Si varnish. (5) Before the varistor element 1 is impregnated with Si varnish and pressurized, a state lower than the atmospheric pressure may be provided to enhance the effect of pressurization. (6) SiO ₂ is used as a powder that does not react with the Si varnish, but any powder that does not react with the impregnating liquid impregnating the varistor element 1 may be used, such as ZrO ₂ , Al ₂ O ₃ , MgO, or a mixture thereof. Etc. can also be used. (7) Before impregnating and curing the varistor element 1 with the Si varnish, the solvent contained in the Si varnish is sufficiently removed by heating to a temperature that does not cause bumping, and then the curing treatment of the Si resin is performed. The outer surface insulating layer 31 having a high density can be formed. (8) By repeating the process from immersion of the Si varnish to polishing of the surface a plurality of times, preferably twice, the varistor element 1 can be impregnated with the Si resin, so that the moisture resistance can be further improved. (9) By chamfering (15) the varistor element 1 and making the ends curved, the Si resin on the external electrode 3 can be partially removed when the Si resin on the external electrode 3 is removed by surface polishing (25). It is possible to prevent mechanical stress from being applied.

In this embodiment, the laminated varistor containing strontium titanate as a main component is described as an example. Even if they are not provided, similar effects can be obtained in electronic parts in general such as thermistors, capacitors, and resistors. Further, the shape may be any shape such as a disk type as well as a lamination type.

[0032]

As described above, according to the present invention, the insulating layer impregnated on the inner surface prevents the deterioration of the moisture resistance, and the insulating layer on the outer surface improves the strength of the electrode. . In addition, the infiltration of moisture and the like from the electrode end can be prevented, so that the moisture resistance is further improved.

[Brief description of the drawings]

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

FIG. 2 is a manufacturing process diagram of a laminated varistor according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a varistor element after impregnation with a Si varnish according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a varistor element after a centrifugation step in one embodiment of the present invention.

FIG. 5 is a sectional view of a varistor element after immersion in toluene according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view of a varistor element after curing of a Si resin in one embodiment of the present invention.

FIG. 7 is a cross-sectional view of a varistor element after polishing in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Varistor element 3 External electrode 5 Si varnish 30 Inner surface insulating layer 31 Outer surface insulating layer

Claims (16)

[Claims] An element having a curved end portion, at least a pair of electrodes formed at predetermined intervals on an outer surface of the element end portion, and a portion of the element surface where the electrode is not formed. And an insulating layer provided to cover an end of the electrode,
An electronic component in which at least a part of the insulating layer is impregnated on an inner surface of the element body. 2. The electronic component according to claim 1, wherein the insulating layer is formed using at least one of a metal alkoxide and a resin. 3. The method according to claim 1, wherein the insulating layer is formed by using a metal alkoxide, and the metal alkoxide has at least one metal selected from silicon, titanium, aluminum, zirconium, yttrium, and magnesium. Electronic components as described. 4. The insulating layer is formed using a resin, and the resin is at least one of a silicon resin, an epoxy resin, an acrylic resin, a polybutadiene resin, and a phenol resin. Electronic components according to the above. 5. The electronic component according to claim 1, wherein the thickness of the insulating layer impregnated on the inner surface of the element body is 10 μm or more. 6. The electronic component according to claim 1, wherein the thickness of the insulating layer on the outer surface of the element body is smaller than the maximum thickness of the electrode adjacent to the insulating layer. 7. An element having a curved end portion, at least a pair of electrodes formed at predetermined intervals on the outer surface of the element end portion, and at least an electrode-free portion of the element surface. An electronic component, comprising: an insulating layer provided on the substrate; 8. A step of forming at least a pair of electrodes at predetermined intervals on the outer surface of the end of the element body having a curved end, and then applying the outer surface of the element to an impregnating liquid containing at least an organic substance. Contacting the element body outer surface with the impregnating liquid, and removing a part of the impregnating liquid covering the element body outer surface, and then curing the organic matter in the impregnating liquid, Removing the hardened organic matter from the outer surface of the electrode of the element body by polishing. 9. The method for manufacturing an electronic component according to claim 8, wherein the step of bringing the element body into contact with the impregnation liquid is repeated a plurality of times. 10. The method according to claim 8, wherein the organic material contains at least one of a metal alkoxide and a resin. 11. The electronic component according to claim 8, wherein the organic substance includes a metal alkoxide, and the metal alkoxide is at least one metal alkoxide of silicon, titanium, aluminum, zirconium, nitrite, and magnesium. Production method. 12. The electronic device according to claim 8, wherein the organic material includes a resin, and the resin is at least one of a silicon resin, an epoxy resin, an acrylic resin, a polybutadiene resin, and a phenol resin. The method of manufacturing the part. 13. The method for manufacturing an electronic component according to claim 8, wherein the element body is pressurized while being brought into contact with the impregnating liquid. 14. The method according to claim 8, wherein the organic substance on the outer surface of the element body is removed by at least one of centrifugal separation, washing with a liquid in which the organic substance is soluble, and contact with a powder that does not react with the impregnating liquid. Manufacturing method of electronic components. 15. The powder is made of SiO ₂ , ZrO ₂ , Al
₂ O _3, method for manufacturing the electronic component according to claim 14 comprising at least one or more of MgO. 16. The method of manufacturing an electronic component according to claim 8, wherein the polishing is performed by moving a container containing at least a body and a liquid.