JP3168801B2 - Ceramic capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type ceramic capacitor which is directly soldered to a circuit board.

[0002]

2. Description of the Related Art With the miniaturization and high-speed digitalization of electronic devices, there is a strong demand for electronic components used in these electronic devices to be miniaturized and compatible with high-speed digitalization. For this reason, a chip-type ceramic capacitor using a ceramic dielectric, for example, a chip-type multilayer ceramic capacitor excellent in high-frequency characteristics and small in capacity has been widely used in a capacitor which is a typical electronic component.

This chip-type multilayer ceramic capacitor is provided at both ends of a multilayer dielectric ceramic body composed of a plurality of dielectric ceramic layers and a plurality of internal electrode layers laminated to each other via the dielectric ceramic layers. External electrodes connected to predetermined ones of the internal electrodes are formed.
The mounting on the circuit board is performed by directly bonding the external electrodes 2 of the chip-type multilayer ceramic capacitor 1 and the conductor portions 6 of the circuit board 5 with solder 4 as shown in FIG.

[0004]

Such a chip-type multilayer ceramic capacitor has no flexibility because its main constituent material is ceramic. Therefore, the mounted ceramic capacitor is easily affected by physical stresses such as expansion and contraction due to flexure and thermal stress of the circuit board, and cracks C and the like are generated as shown in FIG. There was something. Such destruction, instead of tantalum electrolytic capacitors and aluminum electrolytic capacitors, as chip-type ceramic capacitors,
Taking advantage of high frequency characteristics and non-polarity, it often occurred when a large-capacity, large-sized chip-type multilayer ceramic capacitor was used.

[0005] As a countermeasure, attempts have been made to minimize the amount of solder used when soldering to a circuit board and to reduce the stress applied to the chip-type multilayer ceramic capacitor via the solder. However, this method makes it difficult to maintain a constant amount of solder with good reproducibility during mass production.On the other hand, if the amount of solder is too small, the bonding strength will be insufficient, and conversely, the reliability of the connection will be deteriorated. Is not a viable solution.

Accordingly, an object of the present invention is to minimize the influence of physical stress applied to a chip-type ceramic capacitor after being mounted on a circuit board, and to reduce the reliability of the chip-type ceramic capacitor without cracking or peeling. Another object of the present invention is to provide a ceramic capacitor having high performance.

[0007]

In order to achieve the above object, a ceramic capacitor according to the present invention comprises a plurality of chip-type ceramic capacitors having external electrodes formed at both ends thereof, which are arranged side by side in the same direction. Adjacent external electrodes are electrically connected by a flexible conductive resin,
Adjacent portions where no external electrodes were provided were mechanically joined by a flexible insulating resin, and the external electrodes formed of a material to which solder was attached among the opposing external electrodes were positioned at diagonal positions to each other. It is characterized by the following.

[0008]

The ceramic capacitor according to the present invention is formed by joining a plurality of ceramic capacitors adjacently with a flexible resin, and the external electrodes soldered to the circuit board are:
They are formed so as to be located diagonally to each other in the joined ceramic capacitors. Therefore, after mounting on a circuit board, even if the ceramic capacitor is stressed via the soldered portion due to bending or thermal stress of the circuit board, the portion of the flexible resin to which the ceramic capacitor is bonded is deformed and the stress is reduced. Be relaxed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the ceramic capacitor according to the present invention will be described below with reference to the drawings, taking a chip-type multilayer ceramic capacitor as an example. FIG. 1 is a perspective view showing a first embodiment, and FIG. 2 is a perspective view showing a state where the ceramic capacitor of the first embodiment of FIG. 1 is mounted on a circuit board by soldering.

The ceramic capacitor of this embodiment has a structure in which two chip-type multilayer ceramic capacitors are adhered to each other. That is, in FIG. 1, reference numeral 1 denotes a chip-type multilayer ceramic capacitor which is juxtaposed and juxtaposed to each other, 2 denotes an external electrode to which solder is applied by applying and baking an electrode paste mainly composed of Ag or the like, and 3 denotes a Pd or the like. It is an external electrode without solder that is coated and baked with a paste as a main component. Reference numeral 7 denotes an epoxy-based flexible conductive resin containing Ag as a main component.
And the external electrode 3 are joined and electrically connected. Reference numeral 8 denotes an epoxy-based insulating resin having flexibility, which mechanically joins the two chip-type multilayer ceramic capacitors 1.

In the ceramic capacitor formed as described above, the external electrodes 2 to which the solder is attached are located at diagonal positions with respect to each other. Therefore, when mounting on a circuit board, FIG.
As shown in (1), only the diagonally positioned external electrodes 2 to which solder is applied are soldered to the conductor portions 6 of the circuit board 5.
In addition, the mounted ceramic capacitor is made of a conductive resin 7 having two laminated ceramic capacitors 1 having flexibility.
Also, since the circuit board 5 is joined by the flexible insulating resin 8, the solder 4
, The portions of the conductive resin 7 having flexibility and the insulating resin 8 having flexibility are easily deformed, and the stress is relieved. For this reason, there is no fear that cracks, peeling, and the like may occur in the ceramic capacitor without being able to withstand the stress.

The external electrode material of the chip type multilayer ceramic capacitor is not limited to the above embodiment. For example, as an external electrode to which solder is attached, there is conventionally known Cu as an external electrode of a multilayer ceramic capacitor.
An electrode, a Ni (lower layer) -Sn (upper layer) plated electrode, a solder plated electrode, or the like can be used. Further, as the external electrode to which no solder is attached, a Ni-based electrode or an electrode obtained by adding a large amount of glass frit to a baked electrode mainly containing Ag can be used.

The conductive resin for electrically connecting the external electrodes of the chip-type multilayer ceramic capacitor or the insulating resin for joining the chip-type multilayer ceramic capacitor is not limited to the above embodiment. For example,
As the conductive resin having flexibility, Cu or the like can be used in addition to Ag as the conductive component, and as the resin component, a silicon resin or the like can be used. Silicon resin or the like can also be used as the flexible insulating resin.

Furthermore, the number and direction of the chip-type multilayer ceramic capacitors to be bonded are not limited to those in the above-described embodiment, but can be appropriately designed according to the capacitance of the ceramic capacitors, the application, and the like. Hereinafter, another embodiment will be described.

FIG. 3 shows a second embodiment in which three chip-type multilayer ceramic capacitors are stacked and joined in the direction of decreasing thickness. The other parts are the same as those of the first embodiment shown in FIG. FIG. 4 shows a third embodiment, in which four chip-type multilayer ceramic capacitors are joined. The other parts are the same as those of the first embodiment shown in FIG.

In the above embodiment, the case of a chip-type multilayer ceramic capacitor has been described as a ceramic capacitor. However, the present invention is not limited to this, and the same applies to a case of a chip-type ceramic capacitor. Needless to say, the effect is obtained.

[0017]

As is clear from the above description, according to the ceramic capacitor of the present invention, after mounting on a circuit board, the ceramic capacitor is subjected to stress through soldering parts due to bending of the board or thermal stress. Even
The stress is relieved at the portion of the flexible resin to which the ceramic capacitor is bonded, and damage such as cracks can be prevented from occurring in the ceramic capacitor. Therefore, a highly reliable ceramic capacitor can be obtained.

This effect is particularly remarkable when applied to a large-capacity, large-sized ceramic capacitor in place of a tantalum electrolytic capacitor or an aluminum electrolytic capacitor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a ceramic capacitor according to the present invention.

FIG. 2 is a perspective view showing a state in which the ceramic capacitor of the first embodiment is soldered and mounted on a circuit board.

FIG. 3 is a perspective view showing a second embodiment of the ceramic capacitor of the present invention.

FIG. 4 is a perspective view showing a third embodiment of the ceramic capacitor of the present invention.

FIG. 5 is a perspective view showing a state in which a conventional ceramic capacitor is mounted on a circuit board by soldering.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip-type multilayer ceramic capacitor 2 External electrode with solder 3 External electrode without solder 4 Solder 5 Circuit board 6 Conductor part of circuit board 7 Flexible conductive resin 8 Flexible insulating resin

Claims (1)

(57) [Claims] 1. A plurality of chip-type ceramic capacitors having external electrodes formed at both ends are juxtaposed and juxtaposed in the same direction, and the adjacent external electrodes are electrically connected with a conductive resin having flexibility. And adjacent portions where the external electrodes are not provided are mechanically joined by a flexible insulating resin, and the external electrodes formed of a material to which solder is attached among the opposing external electrodes are at diagonal positions with respect to each other. A ceramic capacitor, characterized in that: