JP2001358032A - Chip type electronic components - Google Patents

Abstract

(57) [Problem] To provide a chip-type electronic component having high durability against mechanical stress such as bending and tension and further thermal stress, and excellent in reliability. SOLUTION: A ceramic layer 3 and internal electrodes 2a, 2b,
2c, lower and upper external electrodes 5 and 6 provided on both side end surfaces of the multilayer 1, and at least upper and lower external electrodes 6 provided in the multilayer 1 on the side of the upper external electrode 6. And a reinforcing layer 4 having two layers. The reinforcing layer 4 is made of a material having better ductility and malleability than the ceramic layer 3.

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.

[0002]

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

A conventional multilayer ceramic capacitor is shown in FIG.
As shown in FIG. 1, first, the ceramic layer 3 and the internal electrodes 2a, 2
b and 2c are alternately laminated, and only one layer of the reinforcing layer 4 is provided on each of the upper and lower layers of the laminated layers, thereby producing the laminated body 1.

Next, the internal electrodes 2b, 2c of the laminate 1
External electrodes 10 were formed on both exposed end surfaces of the multilayer ceramic capacitor, thereby forming a multilayer ceramic capacitor.

[0005]

However, in such a conventional configuration, the strength of the laminate 1 is low, and the durability against mechanical stress such as bending and tension and further thermal stress is insufficient. In some cases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chip-type electronic component having high durability against mechanical stress such as bending and pulling and thermal stress, and excellent reliability.

[0007]

In order to achieve this object, a chip-type electronic component according to the present invention comprises a reinforcing layer, which is superior in ductility and malleability to a ceramic layer, comprising a ceramic layer and an internal electrode layer. Are provided on the upper and lower external electrode sides of the laminate in which at least two layers are alternately laminated. By adopting such a configuration, cracks are prevented from being generated, and even if a crack is generated, the crack has a function of stopping the progress of the generated crack, so that the above object can be achieved.

Further, in the chip-type electronic component of the present invention, at least one of the reinforcing layers is connected to an external electrode. At this time, it is preferable that the reinforcing layer connected to the external electrode be closest to the upper surface and the lower surface of the laminate.

The first and second external electrodes are formed so as to extend from the side end surface of the laminated body to the upper surface and the lower surface, respectively.
In the direction between the first and second external electrodes, at least one layer of the reinforcing layer has one end between the side end surface of the multilayer body and the end of the external electrode, and the other end has the external end. It is present between the side of the electrode and half of the distance between both end faces of the laminate.

[0010] At least one end of each reinforcing layer is preferably on a non-coplanar surface in a side end surface direction of the laminate.

The reinforcing layer is formed using at least one and the same element as the external electrode. This same element is Ni
It is preferred that

It is preferable that the metal forming the reinforcing layer and the metal forming the external electrode form an alloy.

Further, it is preferable that the external electrode has a two-layer structure of an upper layer and a lower layer, and the lower layer is provided only on the end face of the laminate.
In this case, the lower layer of the external electrode is preferably formed using at least one same element as the internal electrode.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a laminate in which ceramic layers and internal electrode layers are alternately laminated, and first and second layers provided on both side end surfaces of the laminate. An external electrode, and an upper electrode and a lower electrode in the stacked body, each of which is provided on the first and second external electrode sides outside the innermost electrode formed on the outermost side of the formed internal electrodes. A chip-type electronic component having at least two reinforcing layers, which is more excellent in ductility and malleability than the ceramic layer, has high durability against mechanical stress and thermal stress, and has high reliability. It is excellent.

According to a second aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein at least one of the at least two reinforcing layers is connected to an external electrode. Since the shear stress is applied to the electrode as a whole, the shear stress can be dispersed as a whole, so that the durability against mechanical stress and thermal stress is high.

According to a third aspect of the present invention, the reinforcing layer connected to the external electrode is closest to the upper surface and the lower surface of the laminate in at least two reinforcing layers.
In the chip-type electronic component described in (1), by connecting a reinforcing layer that is most susceptible to stress to an external electrode, the durability is further improved with respect to mechanical stress and thermal stress.

According to a fourth aspect of the present invention, the first and second external electrodes are formed so as to extend from the side end surface to the upper surface and the lower surface of the laminate, respectively. In the direction between the electrodes, at least one layer of the reinforcing layer has one end between the side end surface of the laminate and the end of the external electrode, and the other end of the reinforcement layer extends from the side of the external electrode to the end of the laminate. The chip-type electronic component according to claim 1, which is present up to half of the distance between both side end faces, which prevents deterioration of electrical characteristics and exhibits a function as a reinforcing layer.

According to a fifth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein at least one end of each reinforcing layer is on a non-coplanar surface in a side end surface direction of the laminate.
By dispersing the stress applied to the laminated body, durability against mechanical stress and further thermal stress is high and reliability is excellent.

According to a sixth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein the reinforcing layer is formed using at least one same element as the external electrode. Can easily be physically connected.

According to a seventh aspect of the present invention, the same element is Ni
7. The chip-type electronic component according to claim 6, which has a relatively low impedance and is a high-performance chip-type electronic component.

According to an eighth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein the metal forming the reinforcing layer and the metal forming the external electrode form an alloy. Physical connection of external electrodes can be facilitated.

According to a ninth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein the external electrode has a two-layer structure of an upper layer and a lower layer, and the lower layer is provided only on the end face on the side of the laminate. When the laminate and the lower external electrode are fired at the same time, a large stress is applied to the laminate to prevent cracks and the like from occurring.

According to a tenth aspect of the present invention, there is provided the chip-type electronic component according to the ninth aspect, wherein the lower layer of the external electrode is formed using at least one same element as the internal electrode. Since the constituent metal and the metal forming the external electrode form an alloy, the physical and electrical connection between the internal electrode and the external electrode is facilitated, and the shear stress can be dispersed as a whole. The durability against stress and thermal stress is high.

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 cross-sectional view of a multilayer ceramic capacitor according to Embodiment 1 of the present invention, in which 1 is a laminated body, 2a, 2b, and 2c are internal electrodes, 3 is a ceramic layer, and 4 is a reinforcing layer. Reference numeral 5 denotes a lower external electrode, and reference numeral 6 denotes an upper external electrode.

First, a plurality of ceramic layers 3 are stacked, and a predetermined number of reinforcing layers 4 and ceramic layers 3 are alternately stacked thereon. The reinforcing layer 4 is provided on substantially the same surface as shown in FIG. 1, and one end reaches each end surface of the laminated body 1 where the internal electrodes 2b and 2c are exposed, and the other end is formed. In the direction of both end faces of the laminate 1 (horizontal direction in FIG. 1), it is longer than the upper external electrode 6 to be formed later and shorter than の of the horizontal length of the laminate 1.

Next, the internal electrodes 2 are interposed via the ceramic layer 3.
b, 2c are formed. The internal electrodes 2b and 2c are formed such that one ends thereof are exposed to the opposite end surfaces of the multilayer body 1, respectively.

Next, an internal electrode 2a is formed on the internal electrodes 2b and 2c via the ceramic layer 3. The internal electrode 2a is formed so as to face the internal electrodes 2b and 2c via the ceramic layer 3 and not to be exposed at the end of the laminate 1.

Thereafter, the internal electrodes 2b and 2c and the internal electrodes 2
a are alternately laminated via the ceramic layer 3.

Next, the reinforcing layer 4 as described above is formed on the internal electrodes 2b and 2c with the ceramic layer 3 interposed therebetween to obtain a laminate 1.

The reinforcing layer 4 and the internal electrodes 2a, 2b, 2c are formed using an electrode paste containing Ni as a main component.

Next, the internal electrodes 2b, 2
c, An electrode paste containing Ni as a main component and serving as the lower external electrode 5 is applied to the exposed end faces of the reinforcing layer 4 and fired. Thus, by forming the lower external electrode 5, the reinforcing layer 4, and the internal electrodes 2b and 2c using the same element,
Physical connection between the reinforcing layer 4 and the lower external electrode 5 and between the internal electrodes 2b and 2c and the lower external electrode 5 can be easily performed. Also, by using Ni, the impedance can be relatively reduced.

Thereafter, an Ag paste is applied on the lower external electrode 5 and on the upper, lower, and both side surfaces of the laminate 1 and heat-treated to form the upper external electrode 6.

Through the above steps, the multilayer ceramic capacitor according to the first embodiment is manufactured.

(Embodiment 2) FIG. 2 is a sectional view of a multilayer ceramic capacitor according to Embodiment 2 of the present invention.
Reference numerals a and 4b denote reinforcing layers, and the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted.

First, a plurality of ceramic layers 3 are laminated, on which reinforcing layers 4a and 4b and ceramic layers 3 are alternately laminated. The reinforcing layers 4a and 4b are provided on substantially the same plane as shown in FIG. As shown in FIG. 2, one of the reinforcing layers 4 a, 4 b on the front surface side of the laminate 1 is connected to the lower external electrode 5 at one end thereof so as to be electrically connected to the lower surface external electrode 5. It was formed so as to be exposed. Further, among the reinforcing layers 4a and 4b, the reinforcing layer 4b on the inner side of the multilayer body 1 is provided on the end face of the multilayer body 1 so as to be electrically disconnected from the lower external electrode 5 as shown in FIG. It is formed so as not to be exposed.

One end of each of the reinforcing layers 4a and 4b has an outer layer provided on the upper surface and the lower surface of the laminate 1 from the end face of the laminate 1 in the direction of both end faces of the laminate 1 (horizontal direction in FIG. 2). The other end is present between the ends of the electrode 6 (B in FIG. 2), and the other end is closer to both end faces of the laminate 1 than the ends of the upper external electrodes 6 provided on the upper and lower surfaces of the laminate 1. Inside and laminate 1
Is shorter than の of the distance L between both end faces of the multilayer body 1 from the end face.

That is, in the reinforcing layers 4a and 4b, one end of each exists in the section B of FIG. 2, and the other end thereof exists in the section A of FIG.

Next, the internal electrodes 2 are interposed via the ceramic layer 3.
b, 2c are formed. The internal electrodes 2b and 2c are formed such that one ends thereof are exposed to the opposite end surfaces of the multilayer body 1, respectively.

Next, an internal electrode 2a is formed on the internal electrodes 2b and 2c via the ceramic layer 3. The internal electrode 2a is formed so as to face the internal electrodes 2b and 2c via the ceramic layer 3 and not to be exposed at the end of the laminate 1.

Thereafter, the internal electrodes 2b and 2c and the internal electrodes 2
a are alternately laminated via the ceramic layer 3.

Next, the reinforcing layers 4a and 4b as described above are formed on the internal electrodes 2b and 2c with the ceramic layer 3 interposed therebetween, and the laminated body 1 is obtained.

The reinforcing layers 4a, 4b and the internal electrodes 2a, 2
b and 2c are formed using an electrode paste containing Ni as a main component.

Next, the internal electrodes 2b, 2
c, An electrode paste containing Ni as a main component and serving as the lower external electrode 5 is applied to the exposed end faces of the reinforcing layer 4a and fired. As described above, by forming the lower external electrode 5, the reinforcing layer 4a, and the internal electrodes 2b, 2c using the same element, the reinforcing layer 4a, the lower external electrode 5, and the internal electrodes 2b, 2c are formed.
And the lower external electrode 5 can be easily physically connected. Also, by using Ni, the impedance can be relatively reduced.

Thereafter, an Ag paste is applied on the lower external electrode 5 and on the upper, lower, and both side surfaces of the laminate 1 and heat-treated to form the upper external electrode 6.

Through the above steps, the multilayer ceramic capacitor of the second embodiment is manufactured.

In the second embodiment, the reinforcing layer 4b on the inner side of the laminate 1 is formed so as not to be connected to the lower external electrode 5. When the reinforcing layer not connected to the lower external electrode 5 is formed in this manner, the reinforcing layer 4b on the inner side of the multilayer body 1 is not connected, and the surface side of the multilayer body 1, that is, the outermost reinforcing layer 4a is the lower layer. By connecting to the external electrode 6, stress can be dispersed, so that durability against mechanical stress and further thermal stress is improved.
It is needless to say that one end of the reinforcing layer 4b on the inner side of the multilayer body 1 may be exposed to the end face of the multilayer body 1 so as to be electrically connected to the lower external electrode 5.

Although the present invention has been described with reference to the first and second embodiments, various other modifications are possible.

In each of the above embodiments, the reinforcing layer 4
Although only the case where two layers 4a and 4b are provided above and below the laminate 1 has been described, the same effect can be obtained when two or more layers are provided. However, in order to increase the durability of the multilayer ceramic capacitor against mechanical stress and thermal stress, all the reinforcing layers are located above and below the laminated body 1 (in the thickness direction) near the end of the upper external electrode 6. Is desirably present. The reason for this is that when a portion where a crack occurs in the deflection test is examined, there are many interfaces between the laminate 1 and the upper external electrode 6, and the cracks extend obliquely from this interface toward the side surface of the laminate 1. Therefore, by providing the reinforcing layers 4, 4a, and 4b in this portion, generation of cracks can be suppressed.

Further, the reinforcing layers 4, 4a, 4b are made by using a Ni paste. However, the reinforcing layers 4, 4a, 4b need not be made of a metal such as a metal oxide as long as they exhibit ductility and malleability better than the ceramic layer 3. Absent.

In the present invention, by connecting at least the outermost layers 4, 4a of the reinforcing layer to the lower external electrode 5,
Since the stress applied to the outermost reinforcing layers 4 and 4a where the stress is most concentrated is also applied to the lower and upper external electrodes 5 and 6, the shear stress can be dispersed as a whole.
It has high durability against mechanical stress and thermal stress.

In the present invention, it is desirable that the reinforcing layers 4, 4a, 4b be formed as long as possible in order to increase the durability against mechanical stress and thermal stress, but the reinforcing layers 4, 4a, 4b are made of metal. When it is formed, if it is made longer, the distance between the reinforcing layers 4, 4a, 4b provided substantially on the same surface becomes shorter, and there is a possibility that a capacitance component is generated or a short-circuit defect is generated, thereby deteriorating electrical characteristics. Therefore, the laminate 1
The reinforcing layers 4, 4a, 4
b, at least one end thereof is present in the section B of FIG. 2 and the other end thereof is present in the section A of FIG. The ability as 4, 4a, 4b can be exhibited.

In the above embodiment, two reinforcing layers 4, 4a, 4b are formed on substantially the same plane, but three or more reinforcing layers may be formed. Also in this case, the reinforcing layer is always present at least near the end of the upper external electrode 6 in the side end surface direction of the laminate 1.

Further, by forming the lower external electrode 5 and the reinforcing layers 4 and 4a connected to the lower external electrode 5 using at least one same element, the lower external electrode 5 is connected between the reinforcing layers 4 and 4a and the lower external electrode 5. An alloy can be formed and physical connection can be easily performed, and the stress applied to the reinforcing layers 4 and 4a is also applied to the lower and upper external electrodes 5 and 6, thereby dispersing the shear stress as a whole. Therefore, the durability against mechanical stress and thermal stress is high. Of course, the use of the same material results in higher durability against mechanical stress and thermal stress.

Further, by providing the lower external electrode 5 only on the end face of the multilayer body 1, when the multilayer body 1 and the lower external electrode 5 are simultaneously fired, a large mechanical stress and thermal stress are applied to the multilayer body 1, and cracks occur. Can be prevented from occurring. By forming the lower external electrode 5 and the internal electrodes 2b and 2c using at least one same element, an alloy is formed between the lower external electrode 5 and the internal electrodes 2c and 2b,
Physical connections can be easily made.

Further, in the above embodiment, the upper external electrode 6 is made of a metal whose main component is Ag and the lower external electrode 5 is made of a metal whose main component is Ni. When a stress such as a twist is applied to the laminated body 1, this stress is transmitted directly from the lower external electrode 5 to the upper external electrode 6, and the end portion of the upper external electrode 6 The occurrence of cracks in the laminate 1 can be prevented.

In the above embodiment, the multilayer ceramic capacitor having the internal electrodes 2a, 2b, and 2c of the series structure has been described. However, not only the multilayer ceramic capacitor having the internal electrodes of the parallel structure but also the ceramic layer and the internal electrodes are used. The present invention can obtain the same effect in a ceramic electronic component in which are alternately laminated.

[0058]

As described above, the first aspect of the present invention provides
A laminate in which ceramic layers and internal electrode layers are alternately laminated; first and second external electrodes provided on both side end surfaces of the laminate; and an upper portion and a lower portion formed in the laminate. And at least two reinforcing layers provided on the first and second external electrode sides, respectively, outside of the innermost electrode formed on the outermost side of the internal electrodes, wherein the reinforcing layer is larger than the ceramic layer. It is a chip-type electronic component having excellent ductility and malleability, has high durability against mechanical stress and thermal stress, and has excellent reliability.

According to a second aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein at least one of the at least two reinforcing layers is connected to an external electrode. Since the shear stress is applied to the electrode as a whole, the shear stress can be dispersed as a whole, so that the durability against mechanical stress and thermal stress is high.

According to a third aspect of the present invention, the reinforcing layer connected to the external electrode is closest to the upper surface and the lower surface of the laminate in each of the at least two reinforcing layers.
In the chip-type electronic component described in (1), by connecting a reinforcing layer that is most susceptible to stress to an external electrode, the durability is further improved with respect to mechanical stress and thermal stress.

According to a fourth aspect of the present invention, the first and second external electrodes are formed so as to extend from the side end surface of the laminated body to the upper surface and the lower surface, respectively. In the direction between the electrodes, at least one layer of the reinforcing layer has one end between the side end surface of the laminate and the end of the external electrode, and the other end of the reinforcement layer extends from the side of the external electrode to the end of the laminate. The chip-type electronic component according to claim 1, which is present up to half of the distance between both side end faces, which prevents deterioration of electrical characteristics and exhibits a function as a reinforcing layer.

According to a fifth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein at least one end of each reinforcing layer is on a non-coplanar surface in a side end surface direction of the laminate.
By dispersing the stress applied to the laminated body, durability against mechanical stress and further thermal stress is high and reliability is excellent.

According to a sixth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein the reinforcing layer is formed by using at least one same element as the external electrode. Can easily be physically connected.

According to a seventh aspect of the present invention, the same element is Ni
7. The chip-type electronic component according to claim 6, which has a relatively low impedance and is a high-performance chip-type electronic component.

The invention according to claim 8 is the chip-type electronic component according to claim 1, wherein the metal forming the reinforcing layer and the metal forming the external electrode form an alloy. Physical connection of external electrodes can be facilitated.

According to a ninth aspect of the present invention, there is provided the chip-type electronic component according to the first aspect, wherein the external electrode has a two-layer structure of an upper layer and a lower layer, and the lower layer is provided only on the end face on the side of the laminate. When the laminate and the lower external electrode are fired at the same time, a large stress is applied to the laminate to prevent cracks and the like from occurring.

According to a tenth aspect of the present invention, there is provided the chip-type electronic component according to the ninth aspect, wherein the lower layer of the external electrode is formed by using at least one same element as the internal electrode. Since the constituent metal and the metal forming the external electrode form an alloy, the physical and electrical connection between the internal electrode and the external electrode is facilitated, and the shear stress can be dispersed as a whole. The durability against stress and thermal stress is high.

[Brief description of the drawings]

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

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

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

[Explanation of symbols]

 Reference Signs List 1 laminated body 2a internal electrode 2b internal electrode 2c internal electrode 3 ceramic layer 4 reinforcing layer 4a reinforcing layer 4b reinforcing layer 5 lower external electrode 6 upper external electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Naoki Noda 1006 Kadoma Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Yuichi Murano 1006 Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] 1. A laminate in which ceramic layers and internal electrode layers are alternately laminated, first and second external electrodes provided on both side end surfaces of the laminate, and an upper portion and a lower portion in the laminate. And at least two reinforcing layers provided on the first and second external electrode sides, respectively, outside the outermost formed internal electrode of the formed internal electrodes. A chip-type electronic component having more excellent ductility and malleability than the ceramic layer. 2. In each of the at least two reinforcing layers,
The chip-type electronic component according to claim 1, wherein at least one layer is connected to an external electrode. 3. The chip-type electronic component according to claim 2, wherein the reinforcing layer connected to the external electrode is closest to the upper surface and the lower surface of the laminate in at least two reinforcing layers. 4. The first and second external electrodes are formed so as to extend from a side end surface of the multilayer body to an upper surface and a lower surface of the multilayer body, respectively, in a direction between the first and second external electrodes. In at least one layer of the reinforcing layer, one end thereof is present between the side end face of the laminate and the end of the external electrode, and the other end is located between the side of the external electrode and both end faces of the laminate. 1 / distance
2. The chip-type electronic component according to claim 1, wherein the chip-type electronic component is present up to 2. 5. The chip-type electronic component according to claim 1, wherein at least one end of each reinforcing layer is on a non-coplanar surface in a side end surface direction of the laminate. 6. The chip-type electronic component according to claim 1, wherein the reinforcing layer is formed using at least one same element as the external electrode. 7. The chip-type electronic component according to claim 6, wherein the same element is Ni. 8. The chip-type electronic component according to claim 1, wherein the metal forming the reinforcing layer and the metal forming the external electrode form an alloy. 9. The external electrode has a two-layer structure of an upper layer and a lower layer,
The chip-type electronic component according to claim 1, wherein the lower layer is provided only on the laminated body side end surface. 10. The lower layer of the external electrode is formed using at least one same element as the internal electrode.
2. The chip-type electronic component according to item 1.