JPH10154633A - Ceramic electronic component and method of manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Problem] An internal electrode containing Ni as a main metal component, and Ag and Cu
A ceramic electronic component that includes an external electrode made of a sintered body containing a metal component and a glass component whose main components are Ni and Cu, where the boundary between the external electrode and the internal electrode is formed of an alloy phase mainly containing Ni and Cu By doing so, a good bonding property between the electrodes is achieved, and a highly reliable ceramic electronic component is provided. SOLUTION: The metal constituting the external electrode is made of a metal mainly composed of Cu and Ag, and these are used in an atmosphere of low oxygen partial pressure.
By firing at a low temperature in the range of 0 to 800 ° C. and softening, the whole is composed of an alloy phase 6 mainly containing Cu-Ag, and Ni
An external electrode 3 is obtained in which an alloy phase 5 containing Ni-Cu as a main component is formed at the boundary with the internal electrode. Thus, the external electrode 3 can be sintered at a low temperature, deterioration of the electrical characteristics due to reduction of the ceramic component can be prevented, and the manufacturing cost of the external electrode can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic electronic component such as a multilayer ceramic capacitor, a multilayer varistor, a dielectric resonator, a piezoelectric element and the like, and a method of manufacturing the same. The present invention relates to a ceramic electronic component having electrodes and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as an external electrode of a ceramic electronic component having an internal electrode in which Ni is a main metal component (hereinafter referred to as a Ni internal electrode), a metal paint using only Cu powder as a metal material has been used. Sintered film (hereinafter C
u External electrode. ) Was common. This is because Ni and Cu are all solid-solution systems and are liable to form a bond essentially and to easily form a joint between an internal electrode and an external electrode. Since the melting point of Cu is as high as 1083 ° C., a good sintered bonding state is achieved between the Ni internal electrode and the Cu external electrode (that is, the boundary between the Cu external electrode and the Ni internal electrode) and within the Cu external electrode. To achieve this, the firing temperature must be 80
It was necessary to raise the temperature to above 0 ° C. and to perform sintering in a low oxygen partial pressure atmosphere in order to suppress sintering bond inhibition by oxidation. On the other hand, when a ceramic electronic component (ceramic element) is exposed to a high temperature and a low oxygen partial pressure, its ceramic component may be reduced and may cause deterioration in characteristics. .

As described above, when an external electrode of a ceramic electronic component having a Ni internal electrode is formed by sintering a coating film containing Cu powder, Cu and Ni are easily oxidized in the atmosphere. It is necessary to perform sintering in an atmosphere with a low oxygen partial pressure in order to prevent oxidation of sintering, and sintering is usually performed in an N ₂ gas atmosphere. Normally, N ₂ gas atmosphere used industrially contains a trace amount of oxygen, and its oxygen partial pressure reaches several ppm. However, before sintering, the binder or Cu powder contained in the coating film itself becomes N ₂ gas. When a small amount of oxygen in the atmosphere is consumed by combustion or oxidation, the atmosphere during actual sintering has an extremely low oxygen partial pressure, which results in the reduction of ceramic components in ceramic electronic components (ceramic elements). There is.

In order to suppress the reduction of the ceramic in an atmosphere having a low oxygen partial pressure, it is necessary to reduce the firing temperature at the time of forming the external electrode as low as possible to reduce the reduction reaction rate of the ceramic. However, in the conventional paint for forming an external electrode, that is, in a coating film of a metal paint using only Cu powder as a metal material, if this is fired at a low temperature, the sintering state of the formed external electrode itself becomes poor, And Ni
There was also a problem that the bonding property with the internal electrode became insufficient, and as a result, poor electrical characteristics were caused.

A multilayer ceramic capacitor formed by firing an external electrode in an air atmosphere has been proposed (Japanese Patent Laid-Open No. 2-150010). However, in this method, an alloy phase cannot be obtained at the boundary between the external electrode and the internal electrode, and as a result, it is difficult to integrate the external electrode and the internal electrode firmly, and the designed capacity is stably taken out. There was a problem that it was not possible. Further, by firing a high Cu content alloy having a Cu: Ag ratio of 100: 1 to 100: 40 as an external electrode at 900 ° C. or more,
A method of forming a molten state and forming an external electrode has been proposed (JP-A-2-248020). However, this method has a problem that the firing at a high temperature causes the reduction of the ceramic component as described above, resulting in a decrease in insulation resistance or deterioration due to use to cause poor electrical characteristics.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention sinters itself in a good condition without reducing the ceramic of the ceramic element, and furthermore, sinters the Ni internal electrodes to one another. It is an object of the present invention to provide a ceramic electronic component including an external electrode whose parts are integrated with good bonding properties, and a method for manufacturing the same.

[0007]

In order to achieve the above-mentioned object, a ceramic electronic component according to the present invention comprises a ceramic electronic component having an internal electrode in which Ni is a main metal component. An electronic component, wherein the external electrode is made of a sintered body containing a metal component and a glass component, and the constituent metal of the metal component of the external electrode is Ag.
And a metal containing Cu as a main component, and a boundary portion with the internal electrode is formed of an alloy phase containing Ni and Cu as a main component.

In the ceramic electronic component, it is preferable that the constituent metals of the metal component of the external electrode are Ag and Cu, and the boundary with the internal electrode is formed of an alloy phase composed of Ni and Cu.

In the above ceramic electronic component,
The constituent metal of the metal component of the external electrode is mainly composed of Ag and Cu, and at least one type of metal component whose other component forms an alloy with each of Ag and Cu and whose melting point is lower than the melting point of each of Ag and Cu. It is preferable that a boundary portion with the internal electrode be formed of an alloy phase including Ni and Cu.

In the above-mentioned ceramic electronic component,
The constituent metal of the metal component of the external electrode is mainly composed of Ag and Cu, and at least one type of metal component whose other component forms an alloy with each of Ag and Cu and whose melting point is lower than the melting point of each of Ag and Cu. It is preferable that a metal is contained and a boundary between the internal electrode and the internal electrode is formed of an alloy phase including Ni, Cu, and a metal component included as the others.

In the above-mentioned ceramic electronic component,
The constituent metals of the metal component of the external electrode are mainly Ag and Cu, and other components are Bi, Ce, Ga, In, and
It is preferable to include at least one metal selected from Pb, Sn and Zn.

In the above-mentioned ceramic electronic component,
Weight ratio of Ag to Cu (Ag: Cu) of the external electrode is 1: 9
It is preferably in the range of 9 to 99: 1. In the ceramic electronic component, the weight ratio of Ag to Cu (Ag: Cu) of the external electrode is preferably in the range of 3: 7 to 9: 1.

In the above-mentioned ceramic electronic component,
It is preferable that the weight ratio of the metal component included as another component of the external electrode is 0.001 or more with respect to the total weight of Ag and Cu.

In the above-mentioned ceramic electronic component,
It is preferable that the external electrode sintered body includes inorganic oxide particles which are not bonded to the metal component and exist while maintaining the initial particle shape at the time of powder mixing.

In the above-mentioned ceramic electronic component,
Preferably, the inorganic oxide particles are in the form of flakes. In the ceramic electronic component, the flake-like inorganic oxide particles are preferably one kind selected from mica powder and clay powder containing montmorillonite as a main component, or a mixture thereof.

Further, in the ceramic electronic component,
It is preferable that the metal component of the external electrode sintered body is in the range of 60 to 97% by weight and the glass component is in the range of 3 to 40% by weight. Further, in the ceramic electronic component, the internal electrode Ni
It is preferable that the content be in the range of 90 to 100% by weight and the other metal component be in the range of 0 to 10% by weight.

In the above-mentioned ceramic electronic component,
Other metal components constituting the internal electrode are Fe, Co,
It is preferably at least one metal selected from Cu and Cr.

Next, a method of manufacturing a ceramic electronic component according to the present invention is a method of manufacturing a ceramic electronic component including an external electrode attached to an outer edge of a ceramic electronic component having an internal electrode in which Ni is a main metal component. The external electrode is a metal powder obtained by mixing Ag powder and Cu powder, Cu
At least one metal powder selected from a metal powder composed of an Ag alloy, a metal powder having a Cu powder surface coated with Ag, and a metal powder having a Ag powder surface coated with Cu, a glass frit, and an organic material for a binder. A coating containing a substance is applied to the outer edge of the ceramic electronic component to form a coating film, and thereafter, the coating film is fired in a low oxygen partial pressure atmosphere at a temperature in the range of 500 to 800 ° C. The method is characterized in that the external electrode is obtained.

In the above method, the paint is made of Ag and C.
It is preferable that at least one kind of metal powder or metal oxide powder selected from metal components which form an alloy with u and whose melting point is lower than the melting points of Ag and Cu is contained as another additive.

In the above method, the paint is Bi, C
It is preferable that at least one metal powder selected from e, Ga, In, Pb, Sn and Zn is contained as another additive.

In the above method, the paint is In, B
It is preferable to contain, as another additive, an oxide powder of at least one metal component selected from i, Sn and Pb.

In the above method, the weight ratio of Ag to Cu (Ag: Cu) in the metal powder is 1: 99-9.
It is preferably in the range of 9: 1. In the above method, the weight ratio of Ag to Cu in the metal powder (Ag:
Cu) is preferably in the range of 3: 7 to 9: 1.

In the above method, the weight ratio of other metal powder or metal oxide powder added to Ag and Cu as a metal component may be 0.001 or more with respect to the total weight of Ag and Cu. preferable.

[0024] In the above method, the paint is at 900 ° C.
It is preferable to contain inorganic oxide particles having the above softening point. In the above method, the inorganic oxide particles are preferably in the form of flakes.

In the above method, the flake-like inorganic oxide particles are preferably at least one kind of powder selected from mica powder and clay powder containing montmorillonite as a main component.

In the above method, the metal component of the external electrode sintered body is 60 to 97% by weight, and the glass component is 3 to 40% by weight.
Preferably it is in the range of weight%. In the above method, the Ni content of the internal electrode is preferably in the range of 90 to 100% by weight, and the other metal component is preferably in the range of 0 to 10% by weight.

In the above method, the other metal components constituting the internal electrode may be Fe, Co, Cu, Cr
It is preferably at least one metal selected from the group consisting of: Further, in the above method, the atmosphere having a low oxygen partial pressure at the time of firing the external electrode may have an oxygen partial pressure of 0 ppm or more and 1000 pp.
m or less. A more preferred oxygen partial pressure is in the range of 0 to 500 ppm.

The external electrode for a ceramic electronic component and the method of manufacturing the same according to the present invention have the above-mentioned structure. As the material for forming the external electrode, Cu, which is easily alloyed with Ni of the Ni internal electrode, and an alloy with Cu are formed. 500 to 8 by using a metal material containing Ag having a function of lowering the alloy formation temperature and a paint containing a glass material or the like.
Even when firing at a low temperature of 00 ° C., it is possible to obtain an external electrode having a good sintered state and good bonding with the Ni internal electrode. Further, Bi, which has an effect of forming an alloy with Cu and Ag at a low temperature and further lowering the alloy formation temperature,
By including a metal component such as Ce, Ga, In, Pb, Sn, and Zn, it is possible to obtain an external electrode having a better sintered state and good bonding with the Ni internal electrode.

Hereinafter, the formation mechanism of the external electrode of the present invention will be described. Ag and Cu have a eutectic point at 779 ° C., and when a metal powder of Ag and Cu is mixed, a liquid phase is formed at 779 ° C. However, in reality, Ag and Cu partially start bonding at a temperature below the eutectic point to form a substance that lowers the melting point, and the bonding is further promoted starting from this,
A further eutectic of Ag and Cu was formed. Therefore, the sinterability of the metal in the entire external electrode is lower than that of Cu itself, and the entire external electrode is substantially sintered at a temperature lower than the Ag-Cu eutectic point. Will be done.

On the other hand, the eutectic alloy composition (Ag and Cu
Eutectic material) has a lower softening temperature,
It easily migrates to the Ni surface of the internal electrode. As a result, alloying of Ni and Cu from the surface of Ni is promoted by using the eutectic material as a medium, and an alloy is formed. At this time, Ag and C
The eutectic material of u includes Ag which is hardly bonded to Ni, but Ag plays a role of transporting Cu to the Ni surface without inhibiting the bonding between Ni and Cu. As compared with the case where only Cu is used, an alloy of Ni and Cu is formed at a lower temperature, and a better connection state between the internal electrode and the external electrode can be formed.

By the same mechanism, Ag and Cu
Bi that has the effect of forming an alloy and softening at a lower temperature
When metals such as Pb, Sn, and Zn are contained, an alloy of Ni and Cu is formed at a lower temperature, and a favorable bonding state between the internal electrode and the external electrode can be formed. In some cases, an alloy may be formed from Ni, Cu and the additional metal element, and a very good connection state between the internal electrode and the external electrode can be achieved.

Here, Bi, In, Sn, Pb and the like may be added as a metal component, or may be added in the form of an oxide. This is because when these oxides are fired in an atmosphere having a low oxygen partial pressure, they are easily reduced to become metal components in exchange for combustion of the binder contained in the paint. In general, since the oxide particles are relatively fine and hard, they have the advantage of being easily dispersed uniformly in the coating material, and promote the combustion of the binder component when reduced from the oxide to the metal component, and have a ceramic Since it also has a function of suppressing the reduction of the device, it is preferable to add it in the form of an oxide, which makes it possible to form a better external electrode and manufacture a ceramic electronic component.

As apparent from the above description, the present invention provides
A ceramic electronic component including an internal electrode containing i as a main metal component and an external electrode formed of a sintered body containing a metal component containing Ag and Cu as main components and a glass component, wherein a boundary between the external electrode and the internal electrode is provided. By forming the portion with an alloy phase containing Ni and Cu as main components, good bonding between electrodes can be achieved and a highly reliable ceramic electronic component can be provided.

According to the method of the present invention, the metal constituting the external electrode is a metal mainly composed of Cu and Ag, and more preferably the weight ratio of Ag: Cu of the external electrode is 3: 7 to 9: 1. In a low oxygen partial pressure atmosphere at 500 to 8
By firing and softening at a low temperature in the range of 00 ° C,
The whole is composed of an alloy phase mainly composed of Cu-Ag,
i An external electrode having an alloy phase mainly composed of Ni-Cu formed at the boundary with the internal electrode is obtained, whereby low-temperature sintering of the external electrode becomes possible and reduction of the ceramic component of the ceramic electronic component is achieved. Deterioration of electrical characteristics can be prevented, and manufacturing costs of external electrodes can be reduced.

[0035]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. (Example 1) In order to modelly examine the bonding (alloying) state between the Ni internal electrode and the external electrode of the present invention, the average particle diameter was set to 0.1.
A metal paint was prepared by kneading 100 parts by weight of 5 μm Cu powder, 2 parts by weight of ethyl cellulose as a binder component, and 30 parts by weight of terpineol as a solvent.
Separately, Cu powder having an average particle size of 0.5 μm and Ag powder having an average particle size of 1 μm were mixed at a weight ratio shown in Table 1 (total mixing amount of 100 μm).
Parts by weight), 2 parts by weight of ethyl cellulose as a binder component, and 30 parts by weight of terpineol as a solvent were kneaded together with a metal paint. For each paint,
The paint is applied on a Ni metal foil and dried, and the paint film is N ₂
An external electrode material was prepared by firing at a temperature of 500 to 750 ° C. in an atmosphere. N ₂ gas is 20~30pp
The gas had an oxygen partial pressure of m.

After firing, the state of the alloy phase in the cross section was observed with an optical microscope to examine the bonding state between Ni and the external electrode material. As a result, a clear alloy phase was observed from a low temperature in the case where Ag was added, and the alloy phase was composed of Cu and Ni.
As a result of elemental analysis, it was found that the alloy was only an alloy. Table 1 shows the thickness of the alloy phase.

[0037]

[Table 1]

As is clear from Table 1, Cu and Ni are metals that easily form an alloy by nature, but a high temperature is required to form an alloy with a Ni film using Cu powder alone.
It has been found that adding Ag powder to the powder has an effect of forming an alloy of Ni and Cu even at a low temperature. In particular, when the Ag weight% in the metal material was 30 to 90, the alloying was remarkable, and the alloying was confirmed even at a low temperature of 500 ° C.

In the present embodiment, a mixed powder of Cu powder and Ag powder was used, but Ag-Cu alloy powder and Cu powder were mixed with A powder.
Similar results were obtained using a powder coated with g and a powder coated with Cu on an Ag powder.

Example 2 In order to modelly examine the bonding (alloying) state between the Ni internal electrode and the external electrode of the present invention,
A metal paint obtained by kneading only Cu powder having an average particle size of 0.5 μm with ethyl cellulose as a binder component and terpineol as a solvent;
Powder and Ag powder having an average particle diameter of 1 μm are blended at a predetermined ratio, and further, a powder obtained by adding and mixing Sn powder having an average particle diameter of 1 μm in a weight ratio of 0.02 with respect to the total weight of Ag and Cu, A metal coating kneaded with ethyl cellulose as a binder component and terpineol as a solvent was prepared. For each of these paints, an external electrode material was formed by firing on a Ni metal foil as in Example 1. After firing, the state of the alloy phase in the cross section was observed with an optical microscope to examine the bonding state between Ni and the external electrode material. as a result,
A clear alloy phase was observed from a low temperature in the case where Ag and Sn were added to Cu, and the alloy phase was composed of Cu, Ni, and S.
Elemental analysis revealed that it was an alloy of n. Table 2 shows the thickness of the alloy phase.

[0041]

[Table 2]

As is clear from Table 2, Cu and Ni are metals that easily form an alloy by nature, but a high temperature is required to form an alloy with a Ni film using Cu powder alone.
It has been found that the addition of Ag powder and Sn powder to the powder has the effect of producing an alloy containing Ni and Cu as main components even at a low temperature. Further, from a comparison with Example 1, it was found that an alloy was easier to be formed by adding Sn powder than by simply adding Ag powder. In this case, alloying was remarkably achieved in a wide range where the Ag weight% in the metal material was 1 to 99, and alloying was confirmed even at a low temperature of 500 ° C.

In this embodiment, an experiment was described in which the weight ratio of the other metal component Sn added to Cu and Ag was 0.02 with respect to the total weight of Ag and Cu, but the weight ratio of the other metal component Sn was described. Was 0.001 or more with respect to the total weight of Ag and Cu, and the alloy forming effect was confirmed.

Further, in this embodiment, an experiment performed on Sn as another metal component added to Cu and Ag was described. However, an alloy was formed with Ag and Cu, and the melting points of Ag and Cu were the same as those of Ag and Cu. When a metal element lower than the above was confirmed in detail, the same effect was obtained, and alloy formation was confirmed at a low temperature.

Example 3 In order to modelly examine the bonding (alloying) state between the Ni internal electrode and the external electrode of the present invention,
A metal paint obtained by kneading only Cu powder having an average particle size of 0.5 μm with ethyl cellulose as a binder component and terpineol as a solvent;
Powder and Ag powder having an average particle size of 1 μm are blended in a predetermined ratio, and PbO powder having an average particle size of 0.5 μm is further mixed with Ag and C in a weight ratio.
A metal coating was prepared by kneading powder mixed and added so that the Pb content became 0.005 with respect to the total weight of u, together with ethyl cellulose as a binder component and terpineol as a solvent. For each of these paints, an external electrode material was formed by firing on a Ni metal foil as in Example 1. After firing, the state of the alloy phase in the cross section was observed with an optical microscope to examine the bonding state between Ni and the external electrode material. As a result, a clear alloy phase was observed from a low temperature in the case where Ag and PbO were added to Cu, and as a result of elemental analysis, it was found that the alloy phase was an alloy of Cu and Ni only. Table 3 shows the thickness of the alloy phase.

[0046]

[Table 3]

As is clear from Table 3, Cu and Ni are metals that easily form an alloy by nature, but a high temperature is required to form an alloy with a Ni film using Cu powder alone.
It has been found that adding Ag powder and PbO powder to the powder has an effect of forming an alloy of Ni and Cu even at a low temperature. Further, from a comparison with Example 1, it was found that an alloy was formed more easily when PbO powder was also added than when only Ag powder was simply added. In this case, alloying was remarkably achieved in a wide range of 1 to 99% by weight of Ag in the metal material, and alloying was confirmed even at a low temperature of 500 ° C.

In this embodiment, an experiment was described in which the weight ratio of the metal oxide PbO added to Cu and Ag as the metal Pb content was 0.005 with respect to the total weight of Ag and Cu.
The alloy forming effect was confirmed to be 0.001 or more with respect to the total weight of g and Cu.

Further, in this embodiment, an experiment conducted on PbO as a metal oxide to be added to Cu and Ag was described. However, Bi and In which are other metal oxides which promote binder combustion and are themselves reduced are described. When oxides such as Sn and Sn were confirmed in detail, the same effect was obtained, and alloy formation was confirmed at a low temperature.

Example 4 A metal paint was prepared by kneading 100 parts by weight of metal powder, 6 parts by weight of glass frit, and 3 parts by weight of ethyl cellulose as a binder together with terpineol as a solvent. Here, the metal powder includes a Cu powder having an average particle size of 0.8 μm and an average particle size of 1.5 μm.
Only one of the μm Ag powders or a mixture of these at a predetermined ratio was used. In addition, a coating material in which SnO ₂ powder having an average particle size of 0.5 μm was mixed as another component so that the total weight of Ag and Cu was 0.01 by weight as Sn was 0.01%. Further, a coating material in which Zn powder having an average particle size of 1.0 μm as another component was mixed so that the total weight of Ag and Cu was 0.01 in a weight ratio of 0.01 was also prepared.

As an element for evaluation, a Ni internal electrode laminated ceramic capacitor (F characteristic, 0.1 μF product, about 2.0 mm × 1.25 m) made of a barium titanate-based dielectric was used.
m × thickness 0.65 mm), the metal coating was applied to the end of the device and dried, and baked at 650 ° C. in an N ₂ atmosphere to form external electrodes. Conventional example (comparative example)
Using a metal paint prepared in the same manner as the above metal paint except that the metal powder was made of Cu powder alone, applied to the end of the Ni internal electrode multilayer ceramic capacitor and dried,
Firing was performed at 900 ° C. in _two atmospheres (N ₂ gas had an oxygen partial pressure of 20 to 30 ppm) to form external electrodes. Thereafter, the capacity of each sample was confirmed as an index of the bonding state between Ni of the internal electrode and the external electrode.
Table 4 shows the results.

[0052]

[Table 4]

As is clear from Table 4, when the paint was baked at 650 ° C., the sample in which the external electrode was formed using the paint containing Cu powder alone or Ag powder alone as the metal powder was the Ni internal electrode and the external electrode. Poor bonding with electrodes and incomplete extraction of capacitance (capacity extraction ratio in conventional example: 0 to 0)
50%), but in any of the samples in which the external electrode was formed using a paint containing a mixture of Cu powder and Ag powder as the metal powder, the bonding between Ni of the internal electrode and the external electrode was improved. , The tendency to draw out the specified capacity was observed. In particular, those containing 30 to 90% by weight of the Ag powder based on the whole metal powder have considerably improved bonding, and among them, 30 to 60% by weight.
Good contents could be drawn out in all the cases containing by weight. In the case of an electrode obtained by firing a paint containing Cu powder alone as the metal powder, the capacity extraction was improved by raising the firing temperature to 900 ° C. In this example, the capacity extraction ratio was 95 to 100%, and even at a low level, it was 80% or more.

The samples in which the external electrode was formed by using a paint containing a mixture of Cu powder and Ag powder and adding SnO ₂ powder as another component were all used as the Ni electrode of the internal electrode.
And the external electrode was further improved, and the specified capacity could be drawn out. In this case, the bonding was improved when the Ag powder was contained in an amount of 1 to 99% by weight based on the whole metal powder, and in particular, the powder containing 10 to 90% by weight was able to draw good capacity in all the cases. Furthermore, Cu powder and Ag
Samples in which an external electrode was formed using a paint containing Zn powder as an additional component in a mixture of the powders, the bonding between the internal electrode Ni and the external electrode was further improved,
There was a tendency that the specified capacity could be drawn out. Again, A
The bonding was improved by containing 1 to 99% by weight of the g powder based on the whole metal powder, and in particular, those containing 30 to 70% by weight were able to draw out a good capacity in all cases.

FIG. 1 shows an electrode structure of a capacitor using a ceramic according to an embodiment of the present invention, and is a cross-sectional view schematically showing a joint portion between a Ni internal electrode and an external electrode.
That is, a sample in which an external electrode was formed by sintering a coating film of a paint containing Cu powder alone as a metal powder and Cu powder and A
A sample in which an external electrode is formed by sintering a coating film of a paint containing a mixture of Ag powder and Ag powder in an amount of 50% by weight based on the entire metal powder, and further, Cu powder and Ag powder are formed of metal powder. A coating film containing a mixture obtained by adding SnO ₂ powder to Sn at a weight ratio of 0.01 to the total weight of Ag and Cu in a mixture of 50% by weight with respect to the whole is fired to form an external electrode. FIG. 4 is a cross-sectional view schematically showing a joint portion between a Ni internal electrode and an external electrode of a sample on which is formed. FIGS. 2 and 3 are enlarged views of the portion specified by reference symbol A in FIG. 1. FIG. 2 shows that a coating film of a paint containing 50% by weight of Ag powder based on the whole metal powder is fired at 650 ° C. A sample in which an external electrode is formed, or a mixture of Cu powder and Ag powder so that the Ag powder is 50% by weight based on the entire metal powder, wherein SnO ₂ powder is Sn and the weight ratio of Ag and Cu is 0%. The sample was prepared by firing the coating film containing the additive added so as to be 0.011 at 650 ° C. in an N ₂ atmosphere to form an external electrode, or a coating film containing a Cu powder alone as a metal powder. FIG. 3 shows an electrode structure of a sample capacitor in which an external electrode was formed by firing at 900 ° C., and FIG. 3 shows an electrode of a sample capacitor in which a coating film of a paint containing Cu powder alone was fired at 650 ° C. to form an external electrode. Structure. In these figures, 1 is a dielectric layer (ceramic layer), 2 is Ni
Internal electrode, 3 is external electrode, 4 is Cu sintered powder, 5 is Ni-
Cu alloy phase or Ni-Cu-Sn alloy phase (Ni-Cu
Is a Cu-Ag alloy phase or a Cu-Ag-Sn alloy phase (an alloy phase containing Cu-Ag as a main component) or a Cu metal phase, and 7 is a void.

As shown in FIG. 3, C was used as the metal powder.
In the sample in which the external electrode was formed by sintering the coating film of the coating material containing the u powder alone at 650 ° C., the bonding state between the electrodes was not well understood, but as shown in FIG. 650 ° C. at 50% by weight
In the case of the sample in which the external electrodes were formed by baking with Ni, the Ni-
A state where the Cu alloy phase was growing was observed. Further, in this case, it was confirmed that the metal bonding in the external electrode was promoted as compared with the case of using the Cu powder alone, and the continuity as an electrode was also improved. Further, when the coating film of the paint containing only Cu powder was fired at 900 ° C. to form the external electrode, the same alloy state and electrode continuity as described above were confirmed.

Further, a sample in which an external electrode was formed by firing a coating film of a coating material obtained by adding SnO ₂ powder as a component to be added to a mixture of Cu powder and Ag powder at 650 ° C.
As shown in FIG. 2, between the electrodes, that is, the external electrodes 3
The state where the Ni—Cu—Sn alloy phase was growing at the boundary with the internal electrode 2 was observed. Also in this case, the metal bonding in the external electrode is promoted as compared with the case of using the Cu powder alone,
It was confirmed that the continuity as an electrode was further improved.

In this embodiment, the external electrode structure in the case where SnO ₂ powder is added as a component to be added to the mixture of Cu powder and Ag powder is shown as an example. Was formed, and the case where a metal element whose melting point was lower than that of each of Ag and Cu was added was confirmed in detail. As a result, a similar external electrode structure was confirmed.

(Example 5) Cu powder having an average particle diameter of 0.5 μm, Ag powder having an average particle diameter of 1.0 μm, and glass frit were added in an amount of 50% by weight, 42% by weight, and 8% by weight, respectively, based on the whole powder. A metal coating material was obtained by kneading 100 parts by weight of the powder and 3 parts by weight of ethyl cellulose as a binder component together with terpineol as a solvent. This metallic paint was treated with Ni in the same manner as in Example 4.
An internal electrode laminated ceramic capacitor element is coated and dried, and fired at 600 ° C. in an N ₂ atmosphere (N ₂ gas has an oxygen partial pressure of 20 to 30 ppm) to form an external electrode. 100 pieces each of which was fired to form an external electrode and those which were fired at 800 ° C. to form an external electrode were produced. Thereafter, a high-temperature load accelerated life test was performed on each of the samples (300 pieces) thus manufactured. In this test, after Ni-solder plating is applied to the external electrodes of the sample, this is mounted on a predetermined substrate, and DC250V is applied at 150 ° C.
Further, as a comparative sample, a paint prepared in the same manner as described above except that the metal powder was Cu powder alone,
i. An internal electrode laminated ceramic capacitor element was coated and dried at the end, and fired at 900 ° C. in an N ₂ atmosphere to produce 100 external electrodes, and subjected to the same high-temperature load accelerated life test as described above.

Table 5 shows the results, and the average life time (Hr) in the table shows the average time until the insulation resistance of each sample (element) deteriorates and short-circuits.

[0061]

[Table 5]

As is evident from Table 5, it was found that the device life was shortened as the firing temperature was increased. As a result of the analysis, the inventor has revealed that a reduction in device life is caused by a reduction in characteristics due to reduction of ceramic components of the device. Therefore, the reduction of the ceramic component of the element at the time of electrode formation by firing is promoted at higher temperatures, which confirms that the element characteristics are degraded, and the superiority of low-temperature sintering is clarified.

(Example 6) Cu powder having an average particle diameter of 0.5 μm, Ag powder having an average particle diameter of 1.0 μm, and glass frit were added in an amount of 54% by weight, 40% by weight, and 6% by weight, respectively, based on the whole powder. Montmorillonite in an amount such that the volume occupancy of the metal material component (Cu powder and Ag powder) is 5 to 50%, 100 parts by weight of a powder blended so as to give 3 parts by weight of ethyl cellulose as a binder component, and Clay powder as a component was kneaded with terpineol as a solvent to obtain a metal coating. This metal paint is applied to the end of the Ni internal electrode laminated ceramic capacitor element and dried in the same manner as in Example 4, and fired at 650 ° C. in an N ₂ atmosphere (N ₂ gas has an oxygen partial pressure of 20 to 30 ppm). To form an external electrode. Then, N is applied to the external electrode.
An i-solder plating was applied, and the semiconductor device was mounted on a predetermined substrate and subjected to a bending strength test (according to JIS C 6484 bending test). As a comparative sample, an external electrode was formed at an end of a Ni internal electrode laminated ceramic capacitor element using a paint prepared in the same manner as described above except that a clay powder mainly composed of montmorillonite was not added. Then, the same bending test as described above was performed.

As a result of the test, in a comparative sample in which an external electrode was formed using a coating material to which a clay powder containing montmorillonite as a main component was not added, the element was broken when the substrate was bent by 3 to 5 mm. Although the sample was short-circuited, in a sample in which an external electrode was formed using a coating material to which a clay powder containing montmorillonite as a main component was added, no element destruction occurred up to a total number of 10 mm. The addition of the clay powder containing montmorillonite as a main component to the paint can suppress the destruction of the sample (electronic component) due to the bending load of the board during mounting for the following reason. That is, the clay powder containing montmorillonite as a main component has a softening point of 900 ° C. or higher, and maintains its particle shape in an external electrode obtained by firing a coating film without binding to other components such as metal. Disperse at random. For this reason, when stress is applied to the sample (electronic component) due to the deflection of the substrate, the interface between the clay powder containing montmorillonite as a main component and other components such as metal in the electrode becomes a minute sliding surface, and the external surface becomes fine. The entire electrode is plastically deformed, and as a result, the deflection of the substrate is absorbed by the plastic deformation of the external electrode,
Stress on the sample (electronic component) is reduced.

The present inventors further studied the addition of other inorganic oxide particles having a softening point of 900 ° C. or higher, such as mica powder, titanium oxide powder, copper oxide powder, etc., in addition to clay powder containing montmorillonite as a main component. However, it was also confirmed that when these were added, the effect of suppressing the destruction of the sample (electronic component) due to the bending load of the substrate was similarly obtained. Clay powder and mica powder mainly composed of montmorillonite are flake-like particles, and when they are added, the particle surface area is large, and the continuity of the external electrode is more effectively inhibited. Compared to the case where a powder such as copper oxide or titanium oxide having a shape is added, the above-mentioned sliding action at the interface with other components such as metal is more remarkably exhibited, and the sample (electron (Parts) It was also found that the degree of the effect of suppressing destruction was increased. In addition, these clay oxides, mica powders, and inorganic oxides such as titanium oxide and copper oxide containing montmorillonite as a main component can be added as a mixture of two or more selected from them.

Example 7 100 pieces were fired under the same conditions as in Example 5 except that the temperature was 600 ° C. and the firing atmosphere of the external electrode was different in the following oxygen partial pressure. A ceramic capacitor was obtained. (1) Oxygen partial pressure in N ₂ gas atmosphere: 50 ppm (2) Oxygen partial pressure in N ₂ gas atmosphere: 100 ppm (3) Oxygen partial pressure in N ₂ gas atmosphere: 500 ppm (4) N ₂ gas atmosphere Oxygen partial pressure: 1000 ppm (5) Oxygen partial pressure in N ₂ gas atmosphere: 2000 ppm Table 6 shows the results, and the average capacity (nF) in the table is 1 kHz.
The capacitance value at z, 1V is shown.

[0067]

[Table 6]

As is apparent from Table 6, it was confirmed that a practically sufficient product could be obtained at an oxygen partial pressure of 1000 ppm or less in the N ₂ gas atmosphere. In addition, oxygen partial pressure: 50
At 0 ppm or less, the capacity was more stably drawn out, and it was confirmed that a stable product without quality variation was obtained.

[0069]

As described above, according to the present invention, the external electrode of the ceramic electronic component having the Ni internal electrode is
By further adding Ag to Cu that forms an alloy with i, the action of forming an alloy of Cu and Ni at a low temperature is promoted, and the bonding of metal components in the electrode is also improved.
In addition, Ag and Cu are further alloyed with Ag and Cu as other components, and a metal component whose melting point is lower than the melting point of each of Ag and Cu is added. Promotes the alloy forming action of the alloy. Accordingly, at a low firing temperature, a sufficient bond can be obtained between the internal electrode and the external electrode, and an external electrode that is stable in terms of strength can be formed. In addition, an effect that an external electrode having excellent electric and mechanical characteristics can be manufactured with low power consumption without causing deterioration of characteristics of the electronic component due to reduction of the ceramic component is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a capacitor electrode structure using a ceramic according to an embodiment of the present invention, showing a joint portion between a Ni internal electrode and an external electrode.

FIG. 2 is an enlarged cross-sectional view showing a capacitor electrode structure using a ceramic according to one embodiment of the present invention, which is indicated by a symbol A in FIG.

FIG. 3 is an enlarged sectional view of a portion corresponding to a symbol A in FIG. 1 showing a capacitor electrode structure using a ceramic according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dielectric layer (ceramic layer) 2 Ni internal electrode 3 External electrode 4 Cu sintered powder 5 Alloy phase containing Ni-Cu as a main component 6 Alloy phase or Cu metal phase containing Cu-Ag as a main component 7 Vacancies

Claims (28)

[Claims] 1. A ceramic electronic component including an external electrode attached to an outer edge of a ceramic electronic component including an internal electrode in which Ni is a main metal component, wherein the external electrode includes a metal component and a glass component. And the constituent metals of the metal component of the external electrode are Ag and C
A ceramic electronic component comprising: a metal mainly composed of u; and a boundary part between the internal electrode and the internal electrode is formed of an alloy phase mainly composed of Ni and Cu. 2. The method according to claim 1, wherein the metal constituting the metal component of the external electrode is A
2. The ceramic electronic component according to claim 1, wherein g and Cu are formed, and a boundary between the g and Cu is formed of an alloy phase composed of Ni and Cu. 3. 3. The metal constituting the metal component of the external electrode is mainly composed of Ag and Cu, and other components form an alloy with each of Ag and Cu, and their melting points are Ag and Cu.
At least one metal selected from metal components lower than each melting point, and the boundary with the internal electrode is Ni
The ceramic electronic component according to claim 1, wherein the ceramic electronic component is formed of an alloy phase consisting of Cu and Cu. 4. The metal constituting the metal component of the external electrode is mainly composed of Ag and Cu, and other components form an alloy with each of Ag and Cu, and their melting points are Ag and Cu.
At least one metal selected from metal components lower than each melting point, and the boundary with the internal electrode is Ni
2. The ceramic electronic component according to claim 1, wherein the ceramic electronic component is formed of an alloy phase composed of Cu and Cu and a metal component included as the other. 5. The metal constituting the metal component of the external electrode is mainly Ag and Cu, and Bi,
The ceramic electronic component according to claim 1, 3 or 4, comprising at least one metal selected from Ce, Ga, In, Pb, Sn and Zn. 6. A weight ratio (A) of Ag and Cu of the external electrode.
6. The ceramic electronic component according to claim 1, wherein g: Cu) is in the range of 1:99 to 99: 1. 7. A weight ratio (A) of Ag and Cu of the external electrode.
The ceramic electronic component according to claim 2, wherein g: Cu) is in a range of 3: 7 to 9: 1. 8. The weight ratio of a metal component contained as another component of the external electrode is 0.00 to the total weight of Ag and Cu.
The ceramic electronic component according to claim 3, wherein the number is one or more. 9. The external electrode sintered body contains inorganic oxide particles which are not bonded to the metal component and exist while maintaining the initial particle shape at the time of powder mixing. The ceramic electronic component according to any one of the above. 10. The ceramic electronic component according to claim 9, wherein said inorganic oxide particles are in the form of flakes. 11. The ceramic electronic component according to claim 10, wherein the flake-shaped inorganic oxide particles are one selected from mica powder and clay powder containing montmorillonite as a main component, or a mixture thereof. 12. The metal component of the external electrode sintered body is 60
2. The ceramic electronic component according to claim 1, wherein the glass component is in a range of 3 to 40% by weight. 13. The Ni content of the internal electrode is 90-10.
0 to 10% by weight of other metal components in the range of 0% by weight
The ceramic electronic component according to claim 1, wherein 14. The ceramic electronic component according to claim 13, wherein the other metal component forming the internal electrode is at least one metal selected from Fe, Co, Cu, and Cr. 15. A method for manufacturing an electronic component including an external electrode attached to an outer edge of a ceramic electronic component having an internal electrode in which Ni is a main metal component, comprising: a metal in which Ag powder and Cu powder are mixed. Powder, Cu-Ag
At least one metal powder selected from an alloy metal powder, a metal powder having a Cu powder surface coated with Ag, and a metal powder having a Ag powder surface coated with Cu; a glass frit; and an organic material for a binder. Is applied to the outer edge of the ceramic electronic component to form a coating film. Thereafter, the coating film is fired at a temperature in the range of 500 to 800 ° C. in a low oxygen partial pressure atmosphere to thereby form the external coating. A method for manufacturing a ceramic electronic component, comprising forming an electrode. 16. The coating material forms an alloy with each of Ag and Cu, and has a melting point lower than that of each of Ag and Cu. The method for producing a ceramic electronic component according to claim 15, comprising: 17. The method according to claim 17, wherein the paint is Bi, Ce, Ga, In,
17. The method for producing a ceramic electronic component according to claim 15, wherein at least one metal powder selected from Pb, Sn, and Zn is contained as another additive. 18. The method according to claim 18, wherein the paint is In, Bi, Sn and P.
17. An oxide powder of at least one metal component selected from b. as another additive.
3. The method for manufacturing a ceramic electronic component according to claim 1. 19. The method for manufacturing a ceramic electronic component according to claim 16, wherein a weight ratio of Ag to Cu (Ag: Cu) in the metal powder is in a range of 1:99 to 99: 1. 20. The method according to claim 15, wherein a weight ratio of Ag to Cu (Ag: Cu) in the metal powder is in a range of 3: 7 to 9: 1. 21. The weight ratio of other metal powder or metal oxide powder added to Ag and Cu as a metal component to the total weight of Ag and Cu is 0.001 or more. The method for producing a ceramic electronic component according to any one of the above. 22. The method for producing a ceramic electronic component according to claim 15, wherein the coating material contains inorganic oxide particles having a softening point of 900 ° C. or higher. 23. The method according to claim 22, wherein the inorganic oxide particles are in the form of flakes. 24. The flake-like inorganic oxide particles are at least one kind of powder selected from mica powder and clay powder containing montmorillonite as a main component.
3. The method for manufacturing a ceramic electronic component according to claim 1. 25. The metal component of the external electrode sintered body is 60
The method for manufacturing a ceramic electronic component according to claim 15, wherein the glass component is in a range of 3 to 40% by weight, and the glass component is in a range of 3 to 40% by weight. 26. The Ni content of the internal electrode is 90-10.
0 to 10% by weight of other metal components in the range of 0% by weight
The method for manufacturing a ceramic electronic component according to claim 15, wherein 27. The method according to claim 15, wherein the other metal component forming the internal electrode is at least one metal selected from Fe, Co, Cu, and Cr. 28. The method for manufacturing a ceramic electronic component according to claim 15, wherein the atmosphere having a low oxygen partial pressure at the time of firing the external electrode has an oxygen partial pressure of 0 ppm or more and 1000 ppm or less.