JPH113837A - Multilayer ceramic capacitor combining body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To a large capacity multilayer ceramic capacitor of superior reliability with no generation of mounting crack. SOLUTION: A multilayer ceramic capacitor combination body constituted by piling up a plurality of multilayer ceramic capacitors has an exposure surface where an internal electrode is led out. The exposure surface and a metal part 15 of a supporting member for supporting main parts of ceramic sintered body 11A and 13B of the multilayer ceramic capacitor where an external electrode is not provided are mechanically and electrically connected together, and, however, the top and bottom surfaces thereof and the metal part are not bonded. When the number of multilayer ceramic capacitors piled up is increased, the multilayer ceramic capacitor combination body has large capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer ceramic capacitor, and more particularly to a structure of external electrode terminals of a chip-shaped multilayer ceramic capacitor.

[0002]

2. Description of the Related Art A multilayer ceramic capacitor has a small size and a large capacitance, and is used for a wide range of electronic equipment. In recent years, a higher capacitance has been demanded. In order to increase the capacity of the multilayer ceramic capacitor, it is only necessary to increase the number of layers, but as the number of layers increases, uniform firing becomes difficult. Alternatively, a problem such as a decrease in the yield due to an increase in the lamination shift occurs.

[0003] In order to solve these problems, for example, there is a method (means) disclosed in Japanese Utility Model Publication No. 06-014458. That is, a large-capacity capacitor is manufactured by laminating a plurality of multilayer ceramic capacitors in parallel and fixing them with an adhesive, and then bonding a metal terminal plate to external electrodes of the multilayer ceramic capacitors via solder.

[0004] By the way, cream solder is simply applied to a metal terminal plate and heated with a hot plate or a belt furnace.
When the multilayer ceramic capacitor is bonded to the metal terminal plate, a failure that the metal terminal plate is obliquely bonded during the solidification and contraction of the solder frequently occurs. Therefore, the actual fair 06-014458
7, the external electrodes 25 of the multilayer ceramic capacitor are provided so as not to reach the upper and lower surfaces of the ceramic sintered body, and the supporting shelf 21 is attached to the metal terminal plate 23. By providing the adhesive, the occurrence of the adhesion failure can be prevented to some extent.

[0005]

However, external electrodes 2 are provided on the upper and lower surfaces of the main body of the multilayer ceramic capacitor.
Since No. 3 is not provided, moisture in the environment easily reaches the internal electrode portion through the interface between the ceramic sintered body and the external electrode, and there is a problem that the reliability with respect to humidity is reduced. .

In the case of a conventional multilayer ceramic capacitor in which external electrodes are also provided on the upper and lower surfaces of the ceramic sintered body, when the multilayer capacitor is bonded to a metal terminal plate having such a supporting shelf, the multilayer ceramic is bonded. The state is no different from the case where the capacitor alone is mounted on a substrate, and a so-called mounting crack is easily generated, which causes a problem that reliability is reduced.

A technical object (object) of the present invention is to provide a large-capacity multilayer ceramic capacitor which is free from cracks and has excellent reliability.

[0008]

According to the present invention, in order to support a plurality of multilayer ceramic capacitors and a ceramic sintered body of the multilayer ceramic capacitor, internal electrodes of the multilayer ceramic capacitor are drawn out. And a support member for connecting the exposed surfaces to each other, wherein an internal electrode of the multilayer ceramic capacitor is electrically and mechanically coupled via the exposed surface.

[0009]

The stacked multilayer ceramic capacitor has an exposed surface from which the internal electrodes are drawn. The exposed surface is mechanically and electrically coupled to the metal component of the support member that supports the ceramic sintered body main body portion to which the external electrode of the multilayer ceramic capacitor is not provided. The result is a multilayer ceramic capacitor combination. In this way, a large-capacity multilayer ceramic capacitor combined body is obtained, and since the upper and lower surfaces thereof are not combined with the metal component, the reliability is excellent.

If the number of stacked ceramic capacitors is increased, the combined capacity of the multilayer ceramic capacitors becomes large.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012]

First, referring to FIG. 1, a plurality of conventional multilayer ceramic capacitors 11 and 13 are connected to exposed surfaces 11-1 and 13-1, 11-2 and 13-2 from which internal electrodes are drawn out. By stacking them together, the main body structure of the combined multilayer ceramic capacitor of the present invention is obtained.
At this time, the multilayer ceramic capacitors 11 and 13 may be fixed using an adhesive.

Next, as shown in FIG. 2, two metal parts (supporting members) 15 having an L-shaped cross section and a convex part, ie, a convex part 15-1 on one surface, are attached to the metal part 15. Convex part 1
The stacked multilayer ceramic capacitors are placed with 5-1 as a fulcrum. Here, the external electrodes of the stacked multilayer ceramic capacitors and the protrusions 1 of the metal component 15 are formed.
The position of the convex portion 15-1 of the metal component 15 is adjusted in advance so that 5-1 does not contact. Also,
The shape of the metal component is not limited to an L-shaped cross section, and may be a U-shaped or the like.

Adhering the surface of the metal component 15 having no projection 15-1 to the exposed surface from which the internal electrodes of the laminated ceramic capacitor are drawn out using cream solder or a conductive resin. And metal parts 1
5 and the stacked ceramic capacitors are electrically and mechanically connected by the solder portion 17.

In the above example, the convex portion 15-1 of the metal part 15 is formed by bending. However, as shown in FIG. 3, another member is bonded by an adhesive or welding, or FIG. As shown, a metal part having the same effect can be produced by forming a hemispherical convex portion on one surface of the metal part. Furthermore, the same effect can be obtained even if the shape of the convex portion of the metal component is not only the shape shown in FIGS.

In the following, specific examples and comparative examples will be given to illustrate the multilayer ceramic capacitor combination of the present invention.

(Embodiment) In the embodiment, first, the outer dimensions are 5.7 × 5.0 × 3.0 mm and the nominal capacitance is 22 μF.
As shown in FIG. 1, two multilayer ceramic capacitors 11 and 13 were stacked with their external electrodes aligned.

Here, the multilayer ceramic capacitor 1
For the elements 1 and 13, ordinary ones were used in which external electrodes (not shown) were also provided on the upper and lower surfaces of the exposed surfaces from which the internal electrodes were drawn out. The laminated ceramic capacitors thus stacked were bonded to the metal component 15 made of copper in the shape shown in FIG. 2 by soldering to produce 50 laminated ceramic capacitor combined bodies. The average capacitance of the combined multilayer ceramic capacitor was 47 μF, indicating a large capacitance.

In addition, there was no appearance defect such as displacement of the multilayer ceramic capacitor stacked on the metal component 15.

Next, this combined multilayer ceramic capacitor was mounted on an aluminum substrate (not shown) using solder, and a temperature cycle test was performed in a temperature range of -25 ° C. to + 125 ° C. Up to 300 cycles, no failure such as a decrease in capacitance and insulation resistance was observed.

COMPARATIVE EXAMPLE Similar to the embodiment, a comparison is made between the laminated ceramic capacitor stacked and the metal composite 23 having a supporting shelf 21 on one surface as shown in FIG. An example was produced.
Further, it was mounted on an aluminum substrate (not shown), and the same temperature cycle test as in the example was performed. In this case, the number of cycles was 100, and 10 out of 50 insulation failures occurred. As a result of observing the cross-section of the device where the defect occurred, as shown in FIG.
Cracks 27 were confirmed in one.

From the examples and the comparative examples, it was confirmed that the multilayer ceramic capacitor combination according to the present invention can easily realize an increase in capacitance and at the same time have excellent reliability with little occurrence of cracks 27. Was done.

[0023]

According to the present invention, since the convex portion of the metal component supports the multilayer ceramic capacitor without being in contact with the external electrode of the multilayer ceramic capacitor, the molten solder and the like are exposed to the internal electrodes. It does not go around the lower surface portion of the surface. Therefore, even when using a normal multilayer ceramic capacitor in which external electrodes are also provided on the upper and lower surfaces of the main body from the exposed surface from which the internal electrodes are drawn out, the metal parts and the mechanical parts are mechanically only on the exposed surface from which the internal electrodes are drawn out. In addition, since they are electrically coupled, it is possible to obtain a coupled body of a large-capacity multilayer ceramic capacitor which is less likely to crack and has excellent reliability.

[0024] Further, since the laminated multilayer ceramic capacitor is mounted on the protruding portion of the metal component, the metal component and the multilayer ceramic capacitor are bonded. When the bonding material such as solder is cured, the metal component and the multilayer ceramic capacitor are cured. The occurrence of defects due to misalignment is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main body structure of a combined multilayer ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a multilayer ceramic capacitor combination according to an embodiment of the present invention.

FIG. 3 is a perspective view of a metal component (support member) 15 of FIG. 2;

FIG. 4 is a modified example of the metal component (support member) 15 of FIG.

FIG. 5 is a cross-sectional view of the metal component (support member) 15 of FIG. 4 cut along line VV.

FIG. 6 is a perspective view of a comparative example of a combined multilayer ceramic capacitor.

FIG. 7 is a schematic vertical sectional view of a defective product after a temperature-cycle test in the comparative example of FIG. 6;

[Explanation of symbols]

11, 13 Multilayer ceramic capacitor 11-1, 11-2 Exposed surface from which internal electrode is drawn out 13-1, 13-2 Exposed surface from which internal electrode is drawn out 15 Metal component (support member) 17 Solder part 21 Support Shelf 23 Metal parts (metal terminal plate) 25 External electrode 27 Crack 29 Solder part 31 Internal electrode

Claims (1)

[Claims] 1. A plurality of multilayer ceramic capacitors,
A support member for connecting the exposed surfaces of the internal electrodes of the multilayer ceramic capacitor to support the ceramic sintered body of the multilayer ceramic capacitor, wherein the internal electrodes of the multilayer ceramic capacitor are exposed. A multilayer ceramic capacitor combination characterized by being electrically and mechanically coupled via a surface.