JP2002015940A - Chip-type electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip-type electronic component which exhibits high durability with respect to mechanical stresses, such as bending or tensile stress and against thermal stress and exhibits high reliability and also to improve flexibility which is one of reliability estimating items of chip-type electronic components. SOLUTION: With respect to a laminate 11, which is formed by alternately stacking ceramic layers 13 and inner electrode layers 12a, 12b and 12c, plural isolation reinforcing layers 14, exhibiting higher ductility and malleability than the ceramic layers 13, are formed on the outside of the outermost inner electrodes 12a, 12b and 12c, in such a way that their ends are not connected to the counterposing external electrodes 15 and 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type electronic component such as a multilayer ceramic capacitor which is surface-mounted on a printed circuit board for a switching power supply circuit, a DC-DC converter circuit, and a lighting inverter circuit.

[0002]

2. Description of the Related Art Conventionally, various chip-type electronic components mounted on a printed circuit board have been known. For example, there is a multilayer ceramic capacitor as an example. The conventional technology of this multilayer ceramic capacitor will be described below with reference to the drawings.

[0003] As a conventional multilayer ceramic capacitor,
For example, there is one disclosed in JP-A-9-251903. According to that, as shown in FIG.
First, the ceramic layer 33 and the internal electrodes 32a, 32b, 32
c are alternately laminated, and one end of the reinforcing layer 34 provided on the upper and lower layers of the laminated
external electrodes 30 provided on both exposed end faces of
It was configured to be connected to.

[0004]

However, in such a conventional structure, since the reinforcing layer 34 provided on the upper and lower layers of the laminate 31 is only one layer, the strength of the laminate 31 is weak, and the laminate 31 has a low strength. However, there is a problem that durability against mechanical stress such as the above and thermal stress is insufficient, and in some cases, it may be broken. In addition, since one end of the reinforcing layer 34 is connected to the external electrodes 30 provided on the exposed both end surfaces of the internal electrodes 32b and 32c, a capacitance component is generated or a short circuit is generated. Therefore, the electric characteristics may be deteriorated.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and can improve durability against mechanical stress such as bending and tension and further thermal stress, improve flexural strength, and at least one of deterioration of electrical characteristics. It is an object of the present invention to provide a chip-type electronic component capable of realizing one of the following.

[0006]

In order to achieve this object, a chip-type electronic component according to the present invention comprises a first laminated body having an internal electrode layer provided between a first plurality of ceramic layers, and a second laminated body. A plurality of loose reinforcing layers laminated between the ceramic layers, and a second laminate provided outside the first laminate, and an internal electrode layer provided on the first and second laminates. A pair of external electrodes electrically connected to at least one of the external electrodes was provided, and the plurality of loose reinforcing layers were arranged in non-contact with the pair of external electrodes.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that a first laminate having an internal electrode layer provided between a first plurality of ceramic layers and a plurality of sheets laminated between a second plurality of ceramic layers are provided. A second laminate having a loose reinforcing layer and provided outside the first laminate, and electrically connected to at least one of the internal electrode layers provided in the first and second laminates; With a pair of external electrodes joined, the chip-type electronic component characterized in that the plurality of loose reinforcing layers are arranged in non-contact with the pair of external electrodes,
By providing a plurality of loose reinforcing layers, it is possible to realize a highly reliable chip-type electronic component having high durability against mechanical stress and thermal stress, and by providing a plurality of loose reinforcing layers, unnecessary capacity is reduced. It is possible to prevent the plurality of loose reinforcing layers from being in a non-contact structure with the external electrode, which is likely to be generated or that the probability of occurrence of poor bonding with the external electrode is increased and the electrical characteristics are deteriorated.

According to a second aspect of the present invention, the second laminate is provided on both outer sides of the first laminate so as to sandwich the first laminate. By using a chip-type electronic component, a chip-type electronic component with high reliability against mechanical stress and thermal stress and excellent reliability can be realized.

According to a third aspect of the present invention, the first laminate and the second laminate are joined such that the first plurality of ceramic layers and the second plurality of ceramic layers are substantially parallel. By forming the chip-type electronic component according to item 1, it is possible to form a chip-type electronic component by continuously laminating the first laminate and the second laminate, thereby improving productivity.

According to a fourth aspect of the present invention, the loose reinforcement layers formed on the surface of at least one ceramic layer in the second laminate are divided so as not to be in contact with each other. Item 1 is a chip-type electronic component, whereby the stress applied to the loose reinforcing layer can be divided into two, so that a chip-type electronic component with high flexural strength and excellent reliability can be realized. Having.

According to a fifth aspect of the present invention, the thickness of the free reinforcing layer is in the range of 1 to 7 μm.
The chip-type electronic component described above has an effect that the durability against mechanical stress such as bending and tension is greatly improved, and a chip-type electronic component with high flexural strength can be realized. If the thickness of the loose reinforcing layer is less than 1 μm, sufficient durability against mechanical stress such as bending and tension cannot be obtained,
On the other hand, if the thickness exceeds 7 μm, voids, which are a source of cracks, are likely to be formed at the ends of the free reinforcing layer.

According to a sixth aspect of the present invention, the free reinforcing layer is made of Ni.
The chip-type electronic component according to claim 1, wherein the chip-type electronic component has a good adhesion between the free reinforcing layer and the ceramic layer, thereby greatly increasing the flexural strength. This has the effect of realizing a chip-type electronic component with improved performance.

According to a seventh aspect of the present invention, an external electrode is provided up to the side surface of the first and second laminates, and at least a part of at least one of the plurality of free reinforcing layers is formed of the external electrode. The chip-type electronic component according to claim 1, wherein a portion formed on a side surface of the chip-type electronic component is interposed via a ceramic layer, thereby further improving mechanical or thermal strength. .

Hereinafter, a chip type electronic component of the present invention will be described with reference to the drawings using a multilayer ceramic capacitor which is one of the electronic components.

(Embodiment 1) FIG. 1 is a sectional view showing a chip-type electronic component according to Embodiment 1 of the present invention.
1 is a laminate, 12a, 12b and 12c are internal electrodes, 13
Is a ceramic layer, 14 is a loose reinforcing layer, 15 is a lower external electrode, and 16 is an upper external electrode.

First, a plurality of ceramic layers 13 are laminated,
A predetermined number of free reinforcing layers 14 and ceramic layers 13 are alternately stacked on this, and a plurality of free reinforcing layers 14 (however, one free reinforcing layer 14 is formed on the surface of the ceramic layer 13). Form. As shown in FIG. 1, the plurality of loose reinforcing layers 14 are formed such that one end and the other end thereof are not connected to the lower external electrode 15 facing the lower layer.

Next, the internal electrodes 12b and 12c are formed via the ceramic layer 13. The internal electrodes 12b, 12
“c” is formed such that one end is exposed to the opposite end face of the laminate 11.

Next, an internal electrode 12a is formed on the internal electrodes 12b and 12c via a ceramic layer 13. The internal electrode 12a is opposed to the internal electrodes 12b and 12c via the ceramic layer 13 and the laminated body 11
Is formed so as not to be exposed at the end of.

After that, a desired number of internal electrodes 12b and 12c and internal electrodes 12a are alternately laminated via the ceramic layer 13.

Next, a plurality of loose reinforcing layers 14 as described above are formed on the internal electrodes 12b and 12c with the ceramic layer 13 interposed therebetween to form a laminate 11.

The loose reinforcing layer 14 and the internal electrodes 12a, 12
b and 12c are formed using an electrode paste containing Ni as a main component, whereby the loose reinforcing layer 14 has better ductility and malleability than the ceramic layer 13.

Next, the internal electrodes 12 of the laminate 11
An electrode paste containing Ni as a main component and serving as the lower external electrode 15 is applied to the exposed both end surfaces of b and 12c and baked.

As described above, by using Ni for the lower external electrode 15, physical connection between the internal electrodes 12b and 12c and the lower external electrode 15 can be easily performed, and the impedance can be relatively reduced. This is advantageous for circuit design.

Thereafter, an Ag paste is applied on the lower external electrode 15 and on the upper, lower, and both side surfaces of the laminated body 11, and the upper external electrode 16 is formed by heat treatment.

Through the above steps, a multilayer ceramic capacitor according to the first embodiment of the present invention is obtained.

In the first embodiment, the loose reinforcing layer 1
4 is laminated on each side by two layers, and a total of four layers of the free reinforcing layer 14 is used. However, three or more layers of the free reinforcing layer 14 are formed on one side (a total of six or more free reinforcing layers 14). May be provided. Preferably, the number of layers is preferably 6 or less on one side (total number of free reinforcing layers 14 is 12 or less) so as to prevent the element from being enlarged and to reduce the number of manufacturing steps.

Further, in the first embodiment, the number of the free reinforcing layers 14 on both sides is the same number of layers (two layers on each side). However, one free reinforcing layer 14 is two layers and the other free reinforcing layer 14 is two. May be referred to as three layers, and the number of layers may be different.

Further, in the first embodiment, the internal electrodes 12
Although a plurality of free reinforcing layers 14 are laminated on both sides so as to sandwich a, 12b, and 12c, the free reinforcing layer 14 may be provided only on one side depending on the specifications and the environment in which it is used.

In order to increase the durability of the multilayer ceramic capacitor against mechanical stress and thermal stress, the end of at least one free reinforcing layer 14 (preferably all free reinforcing layers 14) (I.e., the upper external electrode 16 provided on the side surface of the multilayer body 11 and the end of the free reinforcing layer 14 are interposed via the ceramic layer 13). Facing each other). The reason for this is that, when a place where a crack occurs in a deflection test, which is one of the reliability evaluation items of a multilayer ceramic capacitor, is investigated,
1 and the upper external electrode 16 have many interfaces, and cracks grow obliquely from this interface toward the side surfaces of the laminate 11. Therefore, by providing the loose reinforcing layer 14 in this portion, the occurrence of cracks can be suppressed.

Further, although the free reinforcing layer 14 is formed using a Ni paste, a metal oxide or the like may be used as long as it exhibits a higher ductility and malleability than the ceramic layer 13.

In the first embodiment, the lower external electrode 15 and the upper external electrode 16 are laminated as external electrodes. However, for example, a single-layer external electrode may be used.
External electrodes having more than two layers may be used. When the external electrode is formed of three or more layers, for example, the upper external electrode 16 shown in FIG.
A bonding layer made of a bonding material such as solder or lead-free solder may be laminated thereon.

(Embodiment 2) FIG. 2 is a sectional view showing a chip-type electronic component according to Embodiment 2 of the present invention.
1 is a laminate, 22a, 22b and 22c are internal electrodes, 23
Is a ceramic layer, 24 is a loose reinforcing layer, 25 is a lower external electrode, and 26 is an upper external electrode.

First, a plurality of ceramic layers 23 are laminated,
A predetermined number of loose reinforcing layers 24 and ceramic layers 23 are alternately stacked on this to form a plurality of loose reinforcing layers 24.
As shown in FIG. 2, the plurality of loose reinforcing layers 24 are divided into two on the same plane, and one ends of the divided loose reinforcing layers 24 face each other on the same plane with a gap therebetween.
Each of the other ends is formed so as not to be connected to the opposing lower external electrode 25.

Next, the internal electrodes 22b and 22c are formed via the ceramic layer 23. The internal electrodes 22b, 22
“c” is formed such that one end is exposed to the opposite end face of the laminate 21.

Next, an internal electrode 22a is formed on the internal electrodes 22b and 22c via a ceramic layer 23. The internal electrode 22a is opposed to the internal electrodes 22b and 22c via the ceramic layer 23, and
Is formed so as not to be exposed at the end of.

After that, a desired number of the internal electrodes 22 b and 22 c and the internal electrodes 22 a are alternately laminated via the ceramic layer 23.

Next, a plurality of loose reinforcing layers 24 as described above are formed on the internal electrodes 22b and 22c with the ceramic layer 23 interposed therebetween to form a laminate 21.

The free reinforcing layer 24 and the internal electrodes 22a, 22
The b and 22c are formed using an electrode paste containing Ni as a main component, whereby the loose reinforcing layer 24 has better ductility and malleability than the ceramic layer 23.

Next, the internal electrode 22 of the laminate 21
An electrode paste containing Ni as a main component and serving as the lower external electrode 25 is applied to the exposed both end surfaces of the b and 22c and fired. After firing, the loose reinforcement layer 24 has a thickness of 3-4 μm.

Thereafter, by forming the upper layer external electrode 26 in the same manner as in the first embodiment, the multilayer ceramic capacitor according to the second embodiment is obtained.

In the first embodiment, the loose reinforcing layer 2
4 is laminated on each side by two layers, and a total of four free reinforcing layers 24 are provided. However, three or more free reinforcing layers 24 are provided on one side (a total of six or more free reinforcing layers 24 in total). May be provided. Preferably, the number of layers is preferably 6 or less on one side (total number of free reinforcing layers 24 is 12 or less) so as to prevent an increase in the size of the element and to reduce the number of manufacturing steps.

Further, in the first embodiment, the number of the free reinforcing layers 14 on both sides is the same number of layers (two layers on each side). However, one free reinforcing layer 14 is used as two layers, and the other free reinforcing layer 14 is used. May be referred to as three layers, and the number of layers may be different.

Further, in the second embodiment, for example, the free reinforcing layer 24 formed on the surface of one ceramic layer 23 is divided to form two free reinforcing layers 24 which are not in contact with each other. 3 or more loose reinforcement layers 2 to be in contact
4 may be provided, and preferably seven or less loose reinforcement layers 24 are provided on one ceramic layer 23 in consideration of productivity and the like.

Further, in the second embodiment, two free reinforcing layers 24 are provided so as not to be in contact with each other on the surface of any ceramic layer 23. However, the free reinforcing layer 24 formed on the surface of the ceramic layer is provided. May be different. That is,
For example, in FIG.
May be formed, and three loose reinforcement layers 24 thereunder may be formed.

Further, in the second embodiment, the internal electrodes 22
Although a configuration in which a plurality of free reinforcing layers 24 are laminated on both sides so as to sandwich a, 22b, and 22c is adopted, the free reinforcing layer 24 may be provided only on one side depending on the specifications and the environment in which it is used.

In order to improve the durability of the multilayer ceramic capacitor against mechanical stress and thermal stress, the end of at least one free reinforcing layer 24 (preferably all free reinforcing layers 24) (That is, the end of the upper external electrode 26 provided on the side surface of the multilayer body 21 and the end of the free reinforcing layer 24 via the ceramic layer 23). Facing each other). The reason is that, when a place where a crack occurs in a deflection test which is one of the reliability evaluation items of the multilayer ceramic capacitor is examined,
1 and the upper external electrode 26 have many interfaces, and cracks grow obliquely from the interface toward the side surfaces of the laminate 21. Therefore, by providing the loose reinforcement layer 24 in this portion, the occurrence of cracks can be suppressed.

Although the free reinforcing layer 24 is formed using a Ni paste, a metal oxide or the like may be used as long as it exhibits a higher ductility or malleability than the ceramic layer 23.

In the second embodiment, the lower external electrode 25 and the upper external electrode 26 are laminated as external electrodes. However, for example, a single-layer external electrode may be used.
External electrodes having more than two layers may be used. When the external electrode is formed of three or more layers, for example, the upper external electrode 26 shown in FIG.
A bonding layer made of a bonding material such as solder or lead-free solder may be laminated thereon.

A configuration in which the first and second embodiments are combined is also conceivable. That is, one loose reinforcing layer is formed on the surface of a certain ceramic layer as in the first embodiment, and a plurality of separate reinforcing layers are formed on the surface of the other ceramic layer so as to be in non-contact with each other as in the second embodiment. This is a configuration in which a loose reinforcement layer is formed.

In the above embodiment, a multilayer ceramic capacitor in which the internal electrode layers have a series structure has been described. However, not only a multilayer ceramic capacitor in which the internal electrode layers have a parallel structure, but also the ceramic layers and the internal electrode layers are alternated. The present invention can obtain the same effect in all chip-type electronic components (for example, a multilayer inductor) stacked on a substrate.

[0051]

As described above, according to the present invention, a first laminate having an internal electrode layer provided between a first plurality of ceramic layers and a plurality of sheets laminated between a second plurality of ceramic layers are provided. A second laminated body having a loose reinforcing layer and provided outside the first laminated body, and a pair electrically connected to at least one of the internal electrode layers provided on the first and second laminated bodies; By providing a plurality of loose reinforcing layers by disposing a plurality of loose reinforcing layers in a non-contact manner with a pair of external electrodes, the durability against mechanical stress and thermal stress is high, A highly reliable chip-type electronic component can be realized, and furthermore, by providing a plurality of loose reinforcing layers, unnecessary capacitance is likely to be generated, or the probability of occurrence of poor connection with an external electrode is increased, and electric characteristics are improved. Deterioration that multiple loose reinforcement The preventable by the external electrode and the non-contact structure.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a chip-type electronic component according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a chip-type electronic component according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional chip-type electronic component.

[Explanation of symbols]

 Reference Signs List 11 laminated body 12a internal electrode 12b internal electrode 12c internal electrode 13 ceramic layer 14 free reinforcing layer 15 lower external electrode 16 upper external electrode 21 laminated body 22a internal electrode 22b internal electrode 22c internal electrode 23 ceramic layer 24 free reinforcing layer 25 lower external electrode 26 upper layer external electrode 30 external electrode 31 laminated body 32a internal electrode 32b internal electrode 32c internal electrode 33 ceramic layer 34 reinforcing layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Iwao Ueno 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Kazuyuki Okano 1006 Kazuma Kadoma, Kazuma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] A first laminated body having an internal electrode layer provided between a first plurality of ceramic layers; and a plurality of loose reinforcing layers laminated between a second plurality of ceramic layers. A second laminate provided outside the laminate, and a pair of external electrodes provided on the first and second laminates and electrically connected to at least one of the internal electrode layers; The chip-type electronic component, wherein the plurality of loose reinforcing layers are arranged in non-contact with the pair of external electrodes. 2. The chip-type electronic component according to claim 1, wherein said second laminate is provided on both outer sides of said first laminate so as to sandwich said first laminate. 3. The first laminate and the second laminate are joined so that the first plurality of ceramic layers and the second plurality of ceramic layers are substantially parallel to each other. The described chip-type electronic component. 4. The chip type according to claim 1, wherein the free reinforcing layers formed on the surface of at least one ceramic layer in the second laminate are divided so as not to be in contact with each other. Electronic components. 5. The chip-type electronic component according to claim 1, wherein the thickness of the free reinforcing layer is in the range of 1 to 7 μm. 6. The chip-type electronic component according to claim 1, wherein the loose reinforcing layer is made of a metal containing Ni as a main component. 7. An external electrode is provided up to a side surface of the first and second laminates, and at least a part of at least one of the plurality of free reinforcing layers is formed on a side surface of the external electrode. 2. The chip-type electronic component according to claim 1, wherein the chip-type electronic component is opposed to the bent portion via a ceramic layer.