JPS61237412A - Chip capacitor and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a chip capacitor having electrode terminals at both ends of a cylindrical dielectric, and a method for manufacturing the same.

(Prior Art) In recent years, with the miniaturization and high-density packaging of electronic devices, chip-type capacitors are increasingly being used.

As this type of chip-type capacitor, a square capacitor represented by a multilayer capacitor and a cylindrical capacitor are in practical use.

Among these, cylindrical chip capacitors are relatively suitable for the multi-mount method, which has recently been attracting attention as a mounting method. This cylindrical chip capacitor has electrode films formed on the inner and outer peripheral surfaces of a cylindrical dielectric made of a dielectric material such as ceramic, and these electrode films are attached to both ends of the dielectric. The electrode film is coated with an insulating resin, and the manufacturing method is as follows.

First, as shown in FIG. 2(a), a cylindrical dielectric body l made of a ceramic material and open at both ends is prepared. Silver (Ag), copper (Cu) is applied to the inner peripheral surface and outer periphery of this dielectric material l.
Alternatively, electrode films 2 and 3 are formed, respectively, by applying a metal paste such as zinc (Zn) and baking it, or by dry or wet plating, as shown in FIG. 2(b). These electrode films 2 and 3 have a separation band 4 with a width d formed near one end of the dielectric 1, and a width d extending inside the through hole 1a of the dielectric 1 from the end face of the other end of the dielectric 1. .

They are separated from each other by a separation band 5. Thereafter, as shown in FIG. 2(c), metal cap terminals 6 and 7 are attached to both ends of the dielectric 1 and soldered (not shown). ), an exterior resin 9 is applied to the outer periphery of the dielectric 1.

By the way, in a cylindrical chip capacitor like the one above, the dielectric ■ is the through hole! The cavity 10 (Fig. 2 (
(See d)), so if an external shock is applied, the dielectric l will break or crack. There was a limit. In addition, since there is a cavity in the dielectric l, the capacitor itself becomes too lightweight, and in the case of a small one,
There was also the problem that it could not be handled smoothly by automatic machines. Furthermore, since air is confined within the cavity IO, the air within the dielectric 1 expands when the exterior resin IO is baked by heating or the like.

For this reason, the air within the dielectric material i is absorbed by the minute gap (not shown) that exists between the dielectric material 1 and the cap terminal 6.7.

), and due to the air coming out of this gap, the exterior resin 10, which has been baked and has not yet hardened, is damaged, as shown by the dotted line in FIG. 2(d). It bulges outward near the cap terminals 7 and 8.

If the exterior resin 9 is torn at this bulge and a pinhole is generated, moisture will enter the dielectric l through this pinhole.
The withstand voltage of the chip capacitor decreases. Furthermore, in the above-mentioned chip capacitor, the electrode 2 is formed by applying a metal paste, wet or dry plating, etc., but the electrode 2 reaches the outside from the inside of the dielectric I through one end surface thereof. It has been extremely difficult to form such an electrode 2 efficiently into a dielectric material.

In particular, when the inner diameter of the dielectric 1 becomes small, it becomes very difficult to form the electrode 2.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems in cylindrical chip capacitors and their manufacture. The aim is to provide highly reliable chip capacitors that will not cause any problems.

Another object of the present invention is to provide a method for manufacturing a chip capacitor in which electrodes can be easily formed and the chip capacitor can be manufactured with high efficiency.

(Structure of the Invention) The first invention of the present application is the structure of a deep capacitor.
Lee-Yu-Kah (Monday: Dainyu) 1. L-g layered laminated paste (
The back surface is provided with an electrode terminal formed at one end thereof and a dielectric layer formed from the electrode terminal to the other end, and an electrode film is formed on the dielectric layer to form a pillar. It is characterized by facing metal injected into the body.

The second invention of the present application relates to a method for manufacturing a chip capacitor according to the first invention of the present application, in which a column that becomes porous by firing is prepared, and the column is made of a dielectric material with one end remaining. The dielectric material is deposited from one end of the column to the other by immersing it in a slurry made of the column and pulling it up, and firing this to form a unit in which a dielectric layer is formed on the column, This unit is immersed in molten metal, and then the molten metal is pressurized to inject the molten metal into the pores of the column. Thereafter, an electrode film is formed on the dielectric layer, and this electrode film and the column are The electrode terminal formed at the one end of the electrode terminal is electrically conductive.

(Effects of the Invention) According to the first invention of the present application, static electricity is generated between the metal poured into the porous column and the electrode film on the dielectric layer formed on the outer peripheral surface of the column. Since the capacitance is obtained, there is no cavity inside the chip capacitor, and the dielectric material is not destroyed by external shocks, etc., and the thickness of the dielectric material can be made as thin as possible, achieving high capacitance and miniaturization. Moreover, it is possible to completely eliminate the possibility that the air inside the dielectric expands when the exterior resin is baked and pinholes are generated in the exterior resin, thereby reducing the reliability of the chip capacitor. Furthermore, since there is no cavity inside and metal is injected, the chip capacitor itself can be appropriately weighted, making it extremely easy to handle with automatic machines.

Furthermore, since the formed dielectric layer can be made bottomed,
Accordingly, the capacity can be increased, and it is also possible to increase the capacity and downsize.

Further, according to the second invention of the present application, since the metal injected into the porous column functions as one electrode of the chip capacitor, the electrode can be formed by injection of molten metal, and the electrode can be formed by injecting molten metal. It is easy to form, and a large number of chip capacitors can be manufactured at once through multi-processing.
Highly mass-producible.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 1(a), a columnar body 11 made of a ceramic material and having a large number of pores H is prepared. This column 11 can be formed, for example, by extrusion molding of a ceramic material.

The column 11 is immersed in a slurry (not shown) made of a dielectric material and pulled up from the other end 11b, leaving one end 11a of the column 11. As a result, the dielectric material is deposited from one end 11a to the other end 11b of the columnar body 11, and is fired.
), a unit 13 in which a dielectric layer 12 having a desired thickness (for example, about 5 to 500 μm) is formed is formed on the columnar body 11. In this case, the column 11
becomes porous when fired. Of course, the dielectric layer 12 is formed densely. Further, the thickness of the dielectric layer to be formed can be controlled by the viscosity of the slurry, the pulling rate, the number of times, the amount of binder, etc.

Next, the unit 13 is housed in a container (not shown 6) in which metal such as lead (Pb) or zinc (Zn) is heated to 330°C to 400°C to melt it, and this container is sealed. After reducing the pressure inside, the unit 13 is immersed in the molten metal such as lead or zinc, and then the inside of the container is pressurized to, for example, 5 to 30 atmospheres. In this process, the air in the pores of the columnar body 11 is removed, and the pores H are filled with arrows A in FIG. 1(C).
As shown, the molten metal (hereinafter referred to as reference numeral 14) is injected from the one end 11a side of the columnar body 11. In this injection step, the pressure inside the container may be reduced while the unit 13 is immersed in the molten metal in the container.

As described above, the metal 1.1 in the pores [1] of the column 11 is
Fortune telling (-ha: λ shi41fi--+ -,,,L
IQ+-) --, )r After immersing in an electroless plating solution (not shown) to form a metal film such as nickel on the surface, this metal film is attached to one end 11a of the column 11.
It is removed by a method such as sandblasting on the dielectric layer 12 in the vicinity of the dielectric layer 12 . As a result, on the surface of the unit 13, as shown in FIG. is formed. The electrode terminal 15 and the electrode film 16 are separated from each other by a separation band 17 formed by a sandblasting method. Note that the separation band 17 may be formed by forming a resist film in advance and removing it after plating.

Next, by applying the exterior resin 18 from the separation strip 17 to the vicinity of the other end 11b of the columnar body 11 and baking it, a depth capacitor 19 having the structure shown in FIG. 1(d) is obtained.
can be obtained.

In this chip capacitor 19, the metal 14 injected into the pores H of the columnar body 11 is electrically connected to the electrode terminal 15, and the columnar body! The electrode film 16 exposed on the other end 11b side of l serves as another electrode terminal 16a, and the metal 14 injected into the pores of the columnar body 11 and the electrode film 16 are connected to the dielectric layer 1.
2 are opposed to each other, and a capacitance is formed between them.

This capacitance is extracted from between the electrode terminals 15 and 16a. Note that the electrode terminal 15 and the electrode film 16 do not necessarily have to be formed at the same time. In addition, both electrode terminals 15.1
6a may have a multilayer structure, and a cap terminal (not shown) may be fitted therein. Furthermore, the electrode terminal I5.16a itself may be formed of a cap terminal.

In this embodiment, the electrode film 16 formed on the dielectric layer I2
Since the electrodes (metal 14) facing each other with the dielectric layer 12 in between are formed by injecting molten lead, zinc, etc. into the pores H of the column 11, electrode formation is greatly simplified. . Further, since the metal injected into the pores H of the columnar body 11 can be an inexpensive material such as lead or zinc, the material cost of the chip capacitor is also reduced. Moreover, column 11
Since metal is injected into the capacitor, the chip capacitor itself can be appropriately weighted, making it easier to handle.

In addition, in the above embodiment, the electrode terminal 15 and the electrode film 16 are formed by wet plating of appropriate materials in addition to wet plating of nickel.
It may be formed by dry plating, and may also be formed by silver (Ag).
It may also be formed by applying or baking a paste such as.

The shape of the column 11 may be cylindrical, triangular, quadrangular, polygonal, star-shaped, or elliptical in cross section. There may be.

Furthermore, the material of the metal 14 is not limited to lead or zinc.

[Brief explanation of drawings]

Figure 1(a), Figure 1(b), Figure 1(C), Figure 1(
d) and FIG. 1(e) are explanatory diagrams of the manufacturing process of a chip capacitor according to the method of the present invention, and FIG. 2(a), respectively. FIG. 2(b), FIG. 2(c), and FIG. 2(d) are explanatory diagrams of a conventional method of manufacturing a chip capacitor, respectively. 11... Column, 12... Dielectric layer, I3.
...unit, I4...metal, 15...electrode terminal, 16...electrode film, 18...exterior resin,
H...Stomata.

Claims (2)

[Claims] (1) On the outer surface of a porous column in which metal is injected, an electrode terminal is formed at one end thereof, and a dielectric layer is formed from the electrode terminal to the other end;
A chip capacitor characterized in that an electrode film is formed on the dielectric layer and faces the metal injected into the columnar body. (2) Prepare a column that becomes porous by firing,
This column is immersed in a slurry made of a dielectric material, leaving one end of the column, and pulled up, and the dielectric material is deposited from one end of the column to the other end, and this is fired to coat the column. A unit with a dielectric layer formed thereon is formed, this unit is immersed in molten metal, the molten metal is then pressurized to inject the molten metal into the pores of the column, and then the molten metal is poured onto the dielectric layer and A method for manufacturing a chip capacitor, characterized in that an electrode film and an electrode terminal are respectively formed on the one end of the columnar body.