JPH02153514A - Manufacture of laminated capacitor - Google Patents

Abstract

PURPOSE:To suppress the generation of unsatisfactory breakdown strength and defective appearance by a method wherein, before conducting a powder coating using resin powder, an integrally formed capacitor unit is dipped into resin paste. CONSTITUTION:Laminated capacitor units 21, 22 and 23 are laminated, external electrodes 24a, 24b, 25a, 25b, 26a and 26b are coupled and formed into one body with each other, and at the same time, lead terminals 29 and 30 are connected. Then, adhesive tapes 31 and 32 are adhered to the tip part of the lead terminals 29 and 30, and the units 21 to 23 are dipped into the vessel 34 wherein fused resin paste 33 is stored. Then, the units 21 to 23, located on the circumference where resin paste is adhered, are dipped into dried resin powder 41. The units 21 to 23 are picked up in the state as it is, the adhered dried resin powder 41 is fused by heating, and then it is hardened. Lastly, the adhesive tapes 31 and 32 are peeled off, and a large capacity laminated capacitor with lead can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a multilayer capacitor, and particularly relates to a method for manufacturing a multilayer capacitor in which a plurality of capacitor units are integrated in order to increase the capacity. .

[Conventional technology]

For example, as one method of obtaining a capacitor device with a larger capacity using a multilayer capacitor, a structure in which a plurality of multilayer capacitor units are stacked and integrated has been proposed.

FIG. 2 is a cross-sectional view for explaining an example of the above multilayer capacitor. Three multilayer capacitor units 1 to 3 (the cross section of the sintered body is omitted) are connected to the external electrode 4a.
, 4b to 6a, and 6b are aligned and overlapped. Each multilayer capacitor unit 1 to 3 is provided by a well-known multilayer capacitor manufacturing method, and has an external electrode 4a.
, 4b to 6a, and 6b are integrated by joining them with solder 7.8. Lead terminals 9.10 are bonded to this solder 7.8, forming a multilayer capacitor with leads.

Further, as schematically indicated by the dashed line A, the entire body is covered with a resin. This resin exterior is turned upside down from the state shown in Fig. 2, embedded in dry resin powder heated from the multilayer capacitor unit l side, heated in that state to melt the dry resin powder, and then solidified. Performed by.

In the multilayer capacitor shown in FIG. 2, a plurality of multilayer capacitor units 1 to 3 are stacked one on top of the other, and lead terminals 7.
8 in parallel, it is possible to achieve a large capacity that cannot be obtained with a single multilayer capacitor unit.

[Technical problem to be solved by the invention] However,
As is clear from Fig. 2, multilayer capacitor unit 1
A gap 11.12 is formed between the external electrodes 4a to 3 due to the thickness of the external electrodes 4a to 6b. Therefore, even if the resin exterior is applied with powder coating as described above, this gap 11
．． In reality, it is impossible to ensure that the exterior resin is filled into the gap 1112 without any gaps, and air bubbles tend to occur due to the gaps 1112.

As a result, a large number of air bubbles tend to exist in the exterior resin, which tends to cause cracks during handling, and defective products with poor dielectric strength and poor appearance.
This caused a decrease in yield.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a large-capacity multilayer capacitor, which is less likely to cause poor voltage resistance or poor appearance, and which can effectively improve yield.

[Means for solving technical problems]

The present invention prepares a plurality of capacitor units in which a pair of external electrodes are formed on the side surface of a sintered body, stacks the plurality of capacitor units, and integrates the external electrodes by bonding them with a conductive bonding agent. , a pair of lead terminals are bonded to the integrated capacitor unit so as to be electrically connected to external electrodes, and the integrated capacitor unit is immersed in resin paste to adhere the resin paste to the outer surface. A resin paste is filled between the capacitor units, the resin powder is applied to the outer surface of the integrated capacitor unit using the viscosity of the resin paste, and the resin powder is melted and solidified to form an exterior. It is characterized by comprising a process.

[Effect]

Prior to powder coating with resin powder, the integrated capacitor unit is dipped into a resin paste. Therefore, the viscous resin paste can be adhered to the outer surface of the capacitor unit and filled into the gaps between the units. Therefore, in the obtained multilayer capacitor,
Since bubbles due to gaps between capacitor units are less likely to occur, cracks, poor pressure resistance, or poor appearance are less likely to occur.

The resin paste is also applied to the outer surface of the integrated capacitor unit, and the resin powder is applied using its viscosity. Therefore, when attaching resin powder,
There is no need to heat the resin powder at all.

That is, the immersion process in the resin paste used in the present invention fills the gaps between the plurality of capacitor units to prevent the generation of air bubbles, and also eliminates the need for heating when powder is attached during powder coating. It serves both purposes. Therefore, it is possible to efficiently manufacture a large-capacity multilayer capacitor without dielectric breakdown voltage defects or appearance defects.

[Explanation of Examples]

First, an electrode paste for forming internal electrodes is applied to one surface of multiple ceramic green sheets, and the ceramic green sheets are stacked, pressed in the thickness direction, and then fired. A sintered body is obtained.

A multilayer capacitor unit is obtained by providing a pair of external electrodes electrically connected to different internal electrodes alternately on a pair of side surfaces of this sintered body.

As for the method of manufacturing this multilayer capacitor unit, a conventionally well-known method of manufacturing a multilayer capacitor can be used.

Next, a plurality of 81-layer capacitor units obtained as described above are prepared and assembled as shown in FIG. That is, a plurality of laminated capacitor units 21, 22, 23
are superimposed to form external electrodes 24a, 24b, 25, respectively.
a, 25b, 26a and 26b with a conductive bonding agent 27.2
8 to join and integrate. Conductive bonding agent 27.2
As the material 8, any material such as solder or conductive adhesive can be used.

Further, the lead terminals 29 and 30 are also bonded using the conductive bonding agent 27 and 28 . The tip sides of the lead terminals 29 and 30 are connected to multilayer capacitor units 21 to 23 as shown in the figure.
is bent to the opposite side. This is to facilitate mounting on a printed circuit board or the like by utilizing the bent tip. However, the lead terminal 9 shown in FIG.
It is also possible to use a straight lead terminal as shown in 10. In addition,
It is preferable to use flat plate-shaped lead terminals 9 and 10.

Next, easily peelable adhesive tapes 31 and 32 are adhered to the tip portions of the lead terminals 29 and 30. This adhesive tape 31
．． 32 is pasted to mask the tip portions of the lead terminals 29 and 30 during the next resin paste adhesion process and resin powder coating. Therefore, it is preferable to use an easily peelable adhesive tape 31, 32, but
It is also possible to use masking materials other than adhesive tapes 31, 32, as long as they can be masked and removed. Note that this mask material may be provided as needed and is not necessarily required.

Next, the plurality of laminated capacitor units 21 to 23 are immersed in the tank 34 shown in the lower part of FIG. 1 in which the molten resin paste 33 is stored, with the orientation upside down as shown in FIG. By this immersion, the resin paste 33 is applied to the gaps 35, 36 between the plurality of laminated capacitor units 21 to 23.
is filled without any gaps. At the same time, the resin paste will adhere to the outer surface of the immersed part. This state,
It is shown in Figure 3.

In FIG. 3, in order to schematically show the adhered resin paste, the laminated capacitors 21 to 230 portions and the gap 3 are shown.
5.36 is marked with a black circle. Although not shown with hunting, the external electrode 24
a to 26b, solder 27.28 and lead terminal 29.3
Note that resin paste is also applied to the outer surface of the 0.

Next, as shown below the arrow in FIG. 3, a tank 42 in which dry resin powder 41 is stored is prepared. Then, a plurality of integrated multilayer capacitor units (21 to 23) having resin paste attached to their peripheries are immersed in this dry resin powder 41 as shown in the direction of the illustrated arrow. In this case, the dry resin powder 41 will adhere to the outer surfaces of the multilayer capacitor units 21 to 23 and the like due to the viscosity of the resin paste 33. Therefore, the tank 42
The integrated multilayer capacitor units 21 to 23 are pulled up and heated to melt the attached dry resin powder 41, and then hardened to form a resin sheath 43 as shown in FIG. That will happen. Thereafter, by peeling off the adhesive tapes 31, 32 pasted near the tips of the lead terminals 29, 30, a large capacity multilayer capacitor with leads can be obtained.

In the f1 layer capacitor shown in FIG. 4, the resin paste 33 is filled in the gaps 35° 36 between the plurality of laminated capacitor units 21 to 23 without any gaps. Further, when applying the resin sheath 43, there is no need to heat the dry resin powder 41 or the multilayer capacitor units 21 to 23, so the resin paste filled in the gaps 35 and 36 between the plurality of multilayer capacitor units 21 to 23 is 33 is difficult to form bubbles.

Therefore, cracks are less likely to occur in the resin exterior, and the occurrence of poor pressure resistance, poor appearance, etc. can be effectively prevented.

Note that the number of stacked multilayer capacitor units is not limited to the illustrated embodiment;
The present invention can also be applied to the production of a multilayer capacitor, which may be formed by stacking individual multilayer capacitor units, or by stacking four or more multilayer capacitor units.

Furthermore, the capacitor units to be stacked are not limited to the laminated type, but may be of the flat type.

Furthermore, regarding the formation positions of the external electrodes 24a to 26b, it is not necessarily necessary to form them on a pair of opposing end surfaces.
It may be formed on other side parts, in which case,
The lead terminal 2930 is joined to be electrically connected to the external electrode at the other side portion where the external electrode is formed.

〔Effect of the invention〕

According to the present invention, since the resin paste is filled in advance in the gaps between stacked capacitor units, air bubbles are less likely to form in the gaps between the capacitor units. It becomes possible to obtain a large-capacity multilayer capacitor that is resistant to defects and has excellent reliability.

In addition, since the resin paste is also applied to the outer surface of the capacitor unit, during powder coating with resin powder, the resin powder can be applied to the surrounding area without heating the resin powder or the capacitor unit. The process can be simplified.

Furthermore, by appropriately combining sintered bodies with different permittivity-temperature characteristics as stacked capacitor units, it is easy to improve the capacitance-temperature characteristics, and the capacitance value can also be improved by stacking capacitor units. By making appropriate selections, capacitors with various capacitance values can be easily realized.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining the process of immersing an integrated capacitor unit in a resin paste in an embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining the conventional manufacturing method of a multilayer capacitor. 3 and 3 are cross-sectional views for explaining the process of attaching dry resin powder, and FIG. 4 is a cross-sectional view of a multilayer capacitor provided with a resin exterior. In the figure, 21 to 23 are capacitor units, 24a
, 24b to 26a, 26b have external 1 as the pole, 27.38
29 and 30 are conductive bonding agents, 29 and 30 are lead terminals, 33 are resin pastes, 41 are resin powders, and 43 are exterior resins. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A step of preparing a plurality of capacitor units in which a pair of external electrodes are formed on the side surface of a sintered body, overlapping the plurality of capacitor units, and bonding the external electrodes with a conductive bonding agent. a step of joining and integrating the integrated capacitor unit; a step of joining a pair of lead terminals to the integrated capacitor unit so as to be electrically connected to an external electrode; and a step of bonding the integrated capacitor unit with a resin paste. A step of immersing the capacitor in the capacitor unit and applying the resin paste to the outer surface and filling the space between the plurality of capacitor units with the resin paste, and applying resin powder to the outer surface of the integrated capacitor unit using the viscosity of the resin paste. A method for manufacturing a multilayer capacitor, comprising: a step of attaching the resin powder; and a step of applying an exterior package by melting and solidifying the resin powder.