JPS6113367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic capacitor and a method of manufacturing the same, and more particularly to a magnetic capacitor that improves loss characteristics (Q characteristics) or stabilizes the characteristics and a method of manufacturing the same.

Capacitor electrodes made of dielectric ceramics such as titanium oxide and barium titanate are mainly made by the silver baking method or the nickel plating method. The former silver baking method has the advantage of being able to form electrodes with excellent electrical properties and solderability, but has the disadvantage of poor mass production, the disadvantage of being expensive because it uses silver, and the disadvantage of being expensive for capacitors. It has a drawback that during use with voltage supplied, so-called migration occurs, in which silver from one electrode migrates to the other electrode through cracks in the porcelain due to the influence of moisture and the like.

On the other hand, the latter nickel-metsuki method has the advantages of excellent mass production, low cost, and no migration, but compared to the silver baking method, Q =
It has the disadvantage that 1/tan δ is small.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ceramic capacitor that can increase Q and prevent deterioration of characteristics, and a method for manufacturing the same.

The first invention of the present application to achieve the above object is to provide a dielectric ceramic, a dielectric synthetic resin coating that can adhere metal to all or a part of the surface of the dielectric ceramic, and Porcelain comprising one metal electrode provided on a synthetic resin coating and the other metal electrode provided on the dielectric synthetic resin coating or the dielectric porcelain. It is related to capacitors.

The dielectric synthetic resin coating in the above invention is CH ₃
A silicone having a (methyl) group is preferable, and for example, silicone KF54, KF393, and KS705F+PS3 manufactured by Shin-Etsu Chemical Co., Ltd. are preferable.

According to the above invention, since the dielectric synthetic resin coating is provided between the metal electrode and the porcelain, there is no possibility that a gap will be created between the porcelain surface and the electrode due to the unevenness of the porcelain surface, and the inside of the porcelain The infiltration of solutions such as acids or alkalis, or moisture, etc., is prevented. Therefore, Q can be increased and deterioration of characteristics can be prevented.

A second invention of the present application relates to a method for manufacturing a ceramic capacitor according to the first invention, which includes impregnating the dielectric ceramic with silicone and heating the silicone at a temperature of 100°C to 600°C. It includes baking the dielectric ceramic to form a silicone film as the dielectric synthetic resin film, and forming the one metal electrode and the other metal electrode on the silicone film by electroless plating. It is characterized by this.

According to the present invention, a silicone film is formed by impregnating silicone and then baking, and then electrodes are formed by electroless plating, so it is possible to reduce the cost of a ceramic capacitor, and
It becomes possible to prevent a solution such as acid or alkali used in electroless plating from penetrating into the interior of the ceramic, and a ceramic capacitor with a large Q can be obtained.

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 First, a disc-shaped dielectric ceramic 1 whose main component is titanium oxide as shown in FIG. 1A is prepared.

Then the structural formula (Me is a methyl group, φ is a phenyl group, n and m are integers) 3% silicone oil KF54 (manufactured by Shin-Etsu Chemical Co., Ltd.) in xylene (silicone oil/xylene x 100 = 3 %) dielectric ceramic 1 shown in FIG. At this time, the dielectric porcelain 1 is placed in a vacuum of 10 ^-2 torr and vacuum suction is applied, and then the porcelain 1 is immersed in a diluted solution of silicone oil in a vacuum.
Vacuum impregnation with oil. As a result, the silicone oil not only adheres to the surface of the porcelain 1 but also penetrates into the interior of the porcelain 1. Next, the vacuum-impregnated product is placed in a centrifuge to remove excess silicone oil. Next, in order to evaporate the xylene, a drying process was performed at 150°C for 30 minutes in the air, and then a baking process was performed at 500°C for 30 minutes in the air, resulting in the surface of the porcelain 1 as shown in Figure 1B. silicone coating 2 as a dielectric synthetic resin coating.
is formed to a thickness of approximately 50 to 100 Å. Although not shown in detail in FIG. 1B, since the silicone oil penetrates into the recesses and inside of the surface of the porcelain 1,
The silicone coating 2 is formed not only on the surface but also on the recesses and the like on the surface.

Next, the silicone coating 2 formed thereon is immersed in a sensitizer containing stannous chloride (SnCl ₂ ) for 3 to 5 minutes.

Next, the sensitized product was washed with water, and then added to an activator containing palladium chloride (Pd Cl ₂ ) in an aqueous solution of 0.07 to 0.4 grams at 40 to 60°C. , perform the activation treatment by soaking for 3 to 5 minutes. Next, wash with water, and then
Heat treatment is performed at a temperature of 80 to 600°C for 5 to 60 minutes. This brings the palladium film into close contact with the silicone coating 2.

Next, the plate that has been treated with the sensitizer and activator is immersed in an electroless plating solution containing sodium hypophosphite (NaH ₂ PO ₂ ) and nickel sulfate (NiSO ₄ ) to form a film with a thickness of 2 μm or more. A nickel layer 3 is formed as shown in FIG. 1C. This electroless plating is performed by a chemical change as shown in the following formula.

NaH ₂ PO ₂ +H ₂ O→NaH ₂ PO ₃ +H ₂ NaH ₂ PO ₃ +NiSO ₄ →Ni +H ₂ SO ₄ +NaPO _3At this time, palladium deposited in the pretreatment process acts as a catalyst and has a reducing effect. As a result, a nickel layer 3 is generated.

Once the nickel layer 3 shown in FIG. 1C is formed, heat treatment is performed at a temperature of 200 to 400°C for 5 to 60 minutes. This heat treatment is performed in the air or in a neutral atmosphere (argon or carbon dioxide gas). If the heating time is in the range of 5 to 60 minutes, the effect of heat treatment can be obtained, but
Preferably it is carried out for 30 to 40 minutes. Of course, the heat treatment may be performed for 60 minutes or more, but the effect of the heat treatment is hardly improved, resulting in a loss of time.

Next, the outer peripheral surface of the disk-shaped porcelain 1 having the silicone coating 2 and the nickel layer 3 is polished to remove at least the nickel layer 3 on the outer peripheral surface, and one metal electrode 4 is placed on the upper surface as shown in FIG. 1D. The other metal electrode 5 is formed on the lower surface. a pair of metal electrodes 4,
5 is, of course, what remains of the nickel layer 3 of FIG. 1C.

Thereafter, terminal members (not shown) such as lead wires are bonded to the pair of metal electrodes 4 and 5, respectively, as necessary, to complete the device.

As a result, it was possible to obtain a ceramic capacitor having Q=1/tan δ=2300 and with little characteristic deterioration.

For comparison, a ceramic capacitor having the same structure as in FIG. 1 except that the silicone film 2 in FIG. 1 was not provided was made in exactly the same manner and Q was determined, and Q=200. Therefore, according to the present invention, Q can be increased by about 10 times. The reason why Q increases significantly in this way is not necessarily clear, but the acid or alkali solution used when forming the pair of metal electrodes 4 and 5 by nickel plating penetrates into the inside of the dielectric ceramic 1. What you do is
This seems to be because the silicone coating 2 prevents this. In this case, the silicone coating 2 is applied to the recesses 6 on the surface of the porcelain 1, as shown in an enlarged view in FIG.
In contrast, when a nickel plating layer is provided directly on the surface of the porcelain 1, nickel is Not only is it difficult to sufficiently penetrate into the recess 6, but also the acid or alkaline solution penetrates into the inside of the porcelain and into the recess 6 and lowers the Q, so it is thought that a large difference in Q occurs between the two.

Example 2 In order to investigate the relationship between the dilution degree of silicone oil and Q when forming the silicone coating 2 in FIG. 1, only the dilution rate with xylene was used.
When the Q was varied from 0.2% to 50%, a ceramic capacitor was manufactured using the same structure and method as in Example 1, and the Q was measured, and the relationship shown in FIG. 3 was obtained. In FIG. 3, the horizontal axis shows the dilution rate, and the vertical axis shows Q. As is clear from this result, 1-10%
Q is 2000 or more or around 2000 in the range of
Effects appear from 0.2% or higher.

Example 3 In order to investigate the relationship between the baking temperature and Q when forming the silicone coating 2 shown in FIG. 1, a large number of ceramic capacitors were made by varying the baking temperature from room temperature to 600° C., and Q was measured. However, except for changing the baking temperature in Example 1, the structure and method were the same as in Example 1.
I made a porcelain capacitor in exactly the same way. Fourth
The figure shows this result. As is clear from Fig. 4, it is possible to obtain a Q of more than 500 in the range of 100 to 600 °C, and a Q of 2000 in the range of 300 to 550 °C.
It becomes possible to obtain the above Q. Therefore 100～
It is desirable to bake the silicone at a temperature in the range of 600°C, and it is more desirable to bake the silicone at a temperature of 300 to 550°C. If the temperature exceeds 600°C, the quality of the silicone changes, making it difficult to obtain favorable results, and if the temperature exceeds 100°C, a significant increase in Q cannot be expected.

Example 4 Similarly to Example 1 described above, a disk-shaped dielectric ceramic 1 as shown in FIG. 5A is prepared, and a silicone coating 2 is formed thereon in the same manner as in Example 1. Next, as in Example 1, processing using a sensitizer,
and treatment with an activator, 80 to 600
A palladium film is formed on the silicone film 2 by heat treatment at a temperature of 5 to 60 minutes. next,
As shown in FIG. 5C, a plating-resistant coating 11 is formed on the side surface on which no electrode is formed. Next, a pair of metal electrodes 4 and 5 made of nickel layers are formed using the same electroless plating method as in Example 1, as shown in FIG. 5D.
In this case, since the plating pretreatment is performed before forming the plating-resistant coating 11, the nickel layer 3 is formed only on the portion where the plating-resistant coating 11 is not formed. As a result, a ceramic capacitor having a Q of 2000 or more can be obtained as in Example 1.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be further modified. For example, the nickel layer 3 in FIG. 1C may be selectively removed by etching to form a silicone coating 2 remaining around the entire circumference as shown in FIG. Also the fifth
After removing the plating-resistant coating 11 in Figure D, the sixth
A structure as shown in the figure may be used. It is also applicable to the case where a silicone coating 2 and a pair of metal electrodes 4, 5 are provided on a cylindrical ceramic 1a as shown in FIG. 7 in the same manner as in the first embodiment. Further, as shown in FIG. 8, a plate-shaped porcelain 1b having a through hole 12
It is also applicable to a structure in which a silicone coating 2 and a pair of metal electrodes 4 and 5 are provided in the same way as in Example 1, and lead wires 13 are connected. It is also applicable to porcelain condensers of various other structures. Also, in the example
KF54 silicone oil was used, but silicone oil KF393 manufactured by Shin-Etsu Chemical Co., Ltd., which similarly has a CH ₃ (methyl) group, and KS705F+PS3, which can produce a rubbery film, can also be used. . Of course, it is not limited to this type of silicone, and may be any other synthetic resin that can be coated with metal and can also prevent acid or alkaline solutions and moisture from entering the interior of the porcelain. good. Further, a solder plating layer or the like may be formed on the metal electrodes 4 and 5 formed by electroless plating. Although it is desirable to provide the silicone coating 2 over the entire surface, a certain degree of effect can be obtained even if the silicone coating 2 is provided only under one metal electrode 4 and not under the other metal electrode 5. Further, the present invention is also applicable to cases where the metal electrodes 4 and 5 are formed of metals other than nickel.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a ceramic capacitor according to an embodiment of the present invention in order of process, Fig. 2 is an enlarged sectional view of an electrode portion, and Fig. 3 is a relationship between the dilution rate of silicone oil and Q in Embodiment 2. A graph showing,
FIG. 4 is a graph showing the relationship between baking temperature and Q in Example 3, FIG. 5 is a sectional view showing the ceramic capacitor according to Example 4 in the order of steps,
8 and 8 are cross-sectional views showing modified examples, respectively. In the symbols used in the drawings, 1 is a dielectric ceramic, 2 is a silicone coating, 3 is a nickel layer, 4 is one metal electrode, and 5 is the other metal electrode.

Claims (1)

[Scope of Claims] 1. Dielectric porcelain, a dielectric synthetic resin coating that is adhered to all or part of the surface of the dielectric porcelain and is capable of metal attachment, and one side provided on the dielectric synthetic resin coating. A ceramic capacitor comprising: a metal electrode; and the other metal electrode provided on the dielectric synthetic resin coating or the dielectric ceramic. 2. The ceramic capacitor according to claim 1, wherein the derivative synthetic resin film is a silicone film having CH ₂ groups (methyl groups). 3. The one metal electrode is a nickel electrode,
3. The ceramic capacitor according to claim 1, wherein said other metal electrode is also a nickel electrode. 4. Dielectric ceramic, a dielectric synthetic resin coating to which metal can be attached, which is fixed to all or a part of the surface of the dielectric ceramic, one metal electrode provided on the dielectric synthetic resin coating, and the above-mentioned A method for manufacturing a ceramic capacitor comprising a dielectric synthetic resin coating or the other metal electrode provided on the dielectric porcelain, comprising: impregnating the dielectric porcelain with silicone; and heating the silicone at 100°C. baking the dielectric ceramic at a temperature of ~600°C to form a silicone film as the dielectric synthetic resin film; and applying the one metal electrode and the other metal electrode onto the silicone film by electroless plating. A method of manufacturing a ceramic capacitor, the method comprising: forming a ceramic capacitor. 5. The method of manufacturing a porcelain capacitor according to claim 4, wherein the silicone is silicone oil diluted to 1 to 10% with a solvent.