JPS6232605B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a multilayer capacitor, particularly suitable for a feedthrough type capacitor.

This type of multilayer capacitor includes a first dielectric sheet made of, for example, porcelain, which has a through hole in the center and has a first electrode on one plane thereof exposed only on the outer peripheral surface of the plane. and a second dielectric sheet having a through hole in the center and provided with a second electrode on one plane thereof exposed only on the circumferential surface of the through hole on the plane, at least one pair of;
Both the first and second electrodes are overlapped except for the vicinity of each exposed portion, and are stacked alternately to form a laminate so that the through holes communicate with each other, while the outer peripheral surface of the laminate and the inner peripheral surface of the through hole The structure is such that external electrode surfaces electrically isolated from each other are formed using silver or the like.

However, the method for forming the external electrode of the multilayer capacitor described above employs a method of applying conductive metal paint to the outer circumferential surface of the multilayer body and the inner circumferential surface of the through hole with a brush or a brush, and then baking it. Therefore, each piece had to be done manually, which resulted in very low productivity and a drawback of uneven quality.

In addition, this method has the disadvantage that the external electrode is applied with a brush or brush, so the thickness of the external electrode cannot be made uniform, and the dimensions of the outer diameter and inner diameter cannot be made uniform. When used as such, there was a major problem in that loading the case and inserting the through shaft into the case could not be carried out smoothly. Furthermore, when manufacturing smaller products, when applying with a brush or a brush, so-called protruding parts are likely to occur, resulting in a short circuit between opposing external electrodes. Moreover,
Silver is used for this external electrode from the viewpoint of workability, but there is also a concern that migration is likely to occur with this silver, and it does not have excellent life characteristics.

This invention was made in view of the above-mentioned drawbacks, and the first and second dielectric sheets each having a through-hole and having different exposed portions are alternately arranged so that the through-holes communicate with each other. After applying external electrodes to the entire laminate by electroless plating, surface polishing is performed to electrically separate external connection electrodes from each other, that is, electrodes on the outer periphery of the laminate and electrodes on the inner periphery of the through holes. It is an object of the present invention to provide a method for manufacturing a multilayer capacitor, which can be mass-produced by forming the capacitor, has high precision with little variation in quality, and is particularly useful for through-type capacitors.

Hereinafter, this invention will be explained in detail with reference to an embodiment shown in the drawings.

As shown in FIG. 1, the multilayer capacitor according to the manufacturing method of the present invention includes at least a pair of donut-shaped first and second dielectric sheets 1 and 2 each having a through hole 1a and 2a in the center. do.

Among the pair of first and second dielectric sheets 1 and 2, on the upper surface 1b of one of the first dielectric sheets 1,
With the same inner diameter as the through hole 1a of the first dielectric sheet 1,
Further, a first electrode 3 made of palladium, platinum, an alloy thereof, or the like and having an outer diameter smaller than the diameter of the first dielectric sheet 1 is formed by coating or printing. Further, the upper surface 2b of the other second dielectric sheet 2 has a through hole 2a having the same outer diameter as the diameter of the second dielectric sheet 2, similarly to the first dielectric sheet 1. A second electrode 4 made of the same material as described above and having an inner diameter larger than that is formed by the same method as described above. Therefore, the first electrode 3 is exposed on the outer peripheral surface side of the through hole 1a of the first dielectric sheet 1, and the second electrode 4 is exposed on the outer peripheral surface side of the through hole 1a of the first dielectric sheet 1.
It will be exposed on the inner peripheral surface side of the dielectric sheet 2.

As shown in FIG. 2, the first and second dielectric sheets 1 and 2 constructed in this manner are alternately laminated in an appropriate number, and a dielectric sheet without electrodes is placed on top as a dummy sheet. 5 to 1
A laminate X is formed by placing at least one of them. In this case, one or more dummy sheets are usually provided under the laminate X as well.

This laminate X, that is, the first and second
The plurality of first and second dielectric sheets 1 and 2 provided with electrodes 3 and 4 are compressed and fired using a press or the like, and the first and second electrodes 3 and 4 are simultaneously fired.

Next, as shown in FIG. 3, the corners Xa, Xa on the upper and lower surfaces of the laminate X and the corners Xc, Xc on the upper and lower sides of the through-hole Xb are chamfered by barrel polishing or the like to form circular arc surfaces. Form.

After chamfering the corners Xa, Xa and Xc, Xc of the laminate X, as shown in FIG. 4, the entire laminate An electroless plating film of, for example, approximately 4 μm in thickness is formed. In this case, after forming the electroless plating film, heat treatment may be performed as appropriate.

After forming the external electrode S on the entire surface of the laminate X,
As shown in FIG. 5, the external electrodes S on the upper and lower surfaces of the laminate X, that is, the upper and lower surfaces of the dielectric sheets 2 and 5 located above and below the laminate X, are polished by surface polishing. As a result, as shown in FIG. 5, the stacked body X is divided into an outer electrode S _A of the stacked body X and an inner electrode S _B of the through hole X _B , which are electrically isolated from each other. The outer electrode S _A is electrically connected to each of the second electrodes 4, and the inner electrode S _B is connected to the first electrode 4.
It will be electrically connected to the electrode 3.

As described above, multilayer capacitors of uniform quality can be manufactured by performing extremely simple operations one after another. Note that the shape of the dielectric sheet used in the present invention is not limited to the circular shape shown in the drawings.

As described above, according to the manufacturing method of the present invention, at least one pair of dielectric sheets provided with electrodes are alternately stacked and fired to form a laminate, and then a chamfering process is performed, and then the laminate is From the simple process of forming external electrodes on the entire surface by electroless plating, and then polishing the top and bottom surfaces of the laminate to divide it into an electrode on the outer periphery of the laminate and an electrode on the inner periphery of the through hole, which are electrically isolated from each other. So,
Mass production becomes possible, and multilayer capacitors of the same quality can be manufactured.

That is, the barrel polishing method can be used for chamfering, the flat polishing method can be used for polishing the upper and lower surfaces, and the electroless plating method can be used for applying external electrodes, all of which are excellent in mass production.

In addition, since the external electrodes are formed by electroless plating, the plating layer can be thin and have a uniform thickness, and the dimensional accuracy is excellent, which simplifies the polishing work.Furthermore, since no silver is used, migration is easy. Coupled with this fact, the dielectric sheet serving as a dummy sheet can be made to have the minimum required thickness, thereby eliminating waste of materials and promoting downsizing of the capacitor body.

Furthermore, the corners of the upper and lower surfaces of the laminate on which the external electrodes are formed and the upper and lower corners of the through holes are chamfered, which reliably prevents the inner and outer peripheral electrodes from peeling off during surface polishing, improving quality. can be achieved.

[Brief explanation of the drawing]

1 is a schematic perspective view showing an example of the shape of a dielectric sheet used in a multilayer capacitor according to the manufacturing method of the present invention, FIG. 2 is a schematic perspective view showing a state in which the insulator sheets of FIG. 1 are laminated, and FIG. The figure is a schematic perspective view showing the state of the laminate shown in FIG. 2 after chamfering treatment,
FIG. 4 is a schematic perspective view showing a state in which electroless plating has been applied, and FIG. 5 is a schematic perspective view showing a state in which a laminate has been polished after electroless plating. 1, 2...first and second dielectric sheets, 1a, 2
a...Through hole, 3, 4...First, second electrode, 5...
...Dummy sheet _, S _B ...Inner circumferential electrode.

Claims (1)

[Claims] 1. A first dielectric ceramic green sheet having a through hole in the center is provided with a first electrode exposed only on the outer peripheral surface of the sheet on one plane, while a second dielectric ceramic green sheet also having a through hole in the center is provided. A second plate exposed only on the circumferential surface of the through hole on one plane of the green sheet.
At least one pair of the first dielectric ceramic green sheet and the second dielectric ceramic green sheet provided with electrodes are stacked together with a dummy sheet consisting of a green sheet to which no electrodes are provided to form a laminate, and this laminate is formed. After firing the body and chamfering the top and bottom corners of this laminate and the top and bottom corners of the through holes, electroless plating is applied to the entire surface of the laminate to form external electrodes, and then this laminate is Manufacturing a multilayer capacitor characterized in that the external electrode is formed by polishing the upper and lower surfaces of the capacitor, and the external electrode is divided into a through-hole inner electrode and a multilayer outer electrode, which are electrically separated from each other. Method.