JPH10144559A - Terminal electrode paste, laminated electronic component and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perfectly stick the end part of an element to an external electrode layer, by mixing a kind of powder which is selected out of nickel powder, nickel powder and a specified amount of cobalt to the nickel powder, copper and palladium, with oxide powder in such a manner that the oxide powder has, a specified volume. SOLUTION: Powder of nickel, copper and copper oxide, as powder for conduction, and anti-reducing ceramic powder, as oxide powder, whose main component is barium titanate are mixed. At this time, compounding is so performed by calculating the weight ratio from density of the respective powders that the vol.% of the anti-reducing ceramic powder is set to be 15-70 as a desirable value. The respective mixed powders, organic binder which is previously adjusted, and vehicle composed of solvent are kneaded, and terminal electrode paste is obtained. Copper is mixed in nickel powder to be greater than 0wt.% and lower than or equal to 5wt.%. Otherwise, copper oxide is mixed to be greater than 0wt.% and lower than or equal to 6wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal electrode paste for obtaining electrical connection with internal electrodes of a laminated electronic component, and a laminate of a laminated ceramic capacitor, a laminated ceramic varistor, a laminated piezoelectric element and the like using the terminal electrode paste. The present invention relates to an electronic component and a method for manufacturing the laminated electronic component.

[0002]

2. Description of the Related Art Conventionally, in a multilayer electronic component such as a multilayer ceramic capacitor, an internal electrode layer is formed of a metal mainly composed of a noble metal such as silver or palladium. Further, in order to obtain electrical conduction with the internal electrode layer, the external electrode layer is formed mainly using silver.

[0003] However, from the viewpoint of manufacturing cost reduction, in order to realize a base metalization of the internal electrode layer, for example,
In a multilayer ceramic capacitor, an internal electrode layer is formed of nickel. Also, in order to obtain electrical continuity, instead of forming the external electrode layer with silver which does not form an alloy with nickel, first, the same nickel as the internal electrode layer is used as the first external electrode layer. A method has been used in which a paste as a main component is applied in the state of a raw chip, the raw chip is fired, and then a second external electrode layer, for example, silver is provided thereon by baking. There is also known a method of baking an external electrode layer after main baking using a paste containing copper as a main component which can easily obtain electrical conduction with nickel of an internal electrode layer.

[0004] After baking the external electrode layer formed by any of the above methods, nickel plating, furthermore,
By performing solder plating for improving solderability, a multilayer ceramic capacitor can be obtained.

[0005]

In the case of a multilayer ceramic capacitor having a base metal such as nickel or the like in its internal electrode layer, since the main firing of the element body is performed at a high temperature of about 1000 ° C. or more, it is necessary to prevent oxidation of the internal electrode layer. And fired in a low oxygen partial pressure atmosphere. For this reason, a reduction-resistant ceramic is used as a dielectric so that the element is not reduced during the main firing.

The above-described nickel plating and solder plating steps are performed by an electrolytic plating method using an electrolytic solution containing metal ions of nickel and an electrolytic solution containing metal ions of tin and lead, respectively. At this time, if the adhesion between the external electrode layer and the multilayer ceramic capacitor element, that is, the sealing property at the end of the element body is not perfect, in other words, a minute gap is formed between the external electrode layer and the multilayer ceramic capacitor element. If so, the electrolytic solution penetrates into the element body by entering from the gap between the terminal extraction portion of the internal electrode layer and the dielectric effective layer, so that the electrolytic solution, that is, water remains in the element body even after the plating step.

[0007] Therefore, in particular, in the multilayer ceramic capacitor using the above-mentioned reduction-resistant ceramic, there is a problem that the insulation resistance of the multilayer ceramic capacitor element after the plating step is reduced, and the life characteristics of the element are remarkably deteriorated. . In addition, even if water permeating the inside of the multilayer ceramic capacitor body is removed after the plating step, in the high temperature and humidity resistance load life test, moisture penetrates inside the body, which also causes a deterioration in characteristics due to a decrease in insulation resistance. There was also.

An object of the present invention is to provide a terminal electrode paste capable of completely adhering an end of a body and an external electrode layer while ensuring electrical conduction between an internal electrode layer and an external electrode layer. It is.

Another object of the present invention is to completely prevent the intrusion of water into the multilayer electronic component body by using the above-mentioned terminal electrode paste for the external electrode layer of the multilayer electronic component, thereby achieving an initial stage. An object of the present invention is to provide a multilayer electronic component having excellent characteristics and life characteristics and a method for manufacturing the multilayer electronic component.

[0010]

Means for Solving the Problems To solve the above problems, the terminal electrode paste according to the present invention contains nickel powder or more than 0% by weight of nickel powder and nickel powder.
A powder obtained by mixing one type of powder selected from cobalt, copper and palladium of not more than weight% and an oxide powder are mixed with each other so that the oxide powder is 15 to 70% by volume. And a vehicle comprising an organic binder and a solvent are mixed and dispersed.

Further, another terminal electrode paste according to the present invention is selected from nickel oxide powder or cobalt oxide and copper oxide of more than 0% by weight and 5% by weight or less based on the nickel oxide powder and the nickel oxide powder. And a powder obtained by mixing one type of powder with an oxide powder.
A powder obtained by mixing so as to be 0 to 60% by volume and a vehicle comprising an organic binder and a solvent are mixed and dispersed.

Another terminal electrode paste according to the present invention is nickel powder or one type of powder selected from cobalt oxide and copper oxide in an amount of more than 0% by weight to 6% by weight with respect to the nickel powder. Is mixed with a powder obtained by mixing the oxide powder and the oxide powder so that the oxide powder becomes 15 to 70% by volume, and a vehicle comprising an organic binder and a solvent. It is.

[0013] Further, another terminal electrode paste according to the present invention is a powder of nickel oxide or nickel oxide powder.
A powder obtained by mixing one kind of powder selected from cobalt, copper and palladium in an amount of more than 4% by weight and not more than 4% by weight, and an oxide powder, wherein the oxide powder is 10 to 60% by volume. The powder is obtained by mixing and dispersing powder obtained by mixing as described above and a vehicle comprising an organic binder and a solvent.

In each of the terminal electrode pastes described above, an oxide powder for completely sealing the end of the element body of the laminated electronic component is added at a compounding ratio within a certain range. When used as an external electrode layer, the end of the element body and the external electrode layer can be completely adhered to each other while ensuring electrical continuity between the internal electrode layer and the external electrode layer.

Next, a laminated electronic component according to the present invention includes a nickel internal electrode layer and an external electrode layer formed from any of the terminal electrode pastes described above. In this case, the terminal electrode paste to which the oxide powder for completely sealing the end of the element body is added at a compounding ratio within a certain range can be used as the external electrode layer of the laminated electronic component. By applying a thickness within a certain range to the terminal extraction part and baking by simultaneous baking, the end of the body and the external electrode layer can be completely adhered, and the penetration of water into the body can be completely prevented. Can be stopped. As a result, a multilayer electronic component that satisfies the initial insulation resistance value and has good life characteristics can be manufactured with high yield.

Next, a method of manufacturing a multilayer electronic component according to the present invention is a method of manufacturing a multilayer electronic component having a nickel internal electrode layer, comprising the steps of chamfering a raw chip of the multilayer electronic component, and taking out terminals of the raw chip. A step of applying and drying any one of the terminal electrode pastes described above at least once as a first external electrode layer, a step of removing the raw chip from the binder, and firing the raw chip; Forming an external electrode layer.

According to the manufacturing method described above, a terminal electrode paste to which an oxide powder for completely sealing the end of the element body is added at a compounding ratio within a certain range is used as an external electrode layer of the laminated electronic component. Since it can be applied to the terminal extraction part of the raw chip with a certain range of thickness and baked by simultaneous firing,
The end of the body and the external electrode layer can be completely adhered,
Intrusion of water into the body can be completely prevented.
As a result, a multilayer electronic component that satisfies the initial insulation resistance value and has good life characteristics can be manufactured with high yield.

The thickness of the terminal electrode paste applied to the terminal extraction portion of the raw chip after drying is 5 to 50 μm.
It is preferred that In addition, the second external electrode layer is
It is preferably formed by applying and baking a paste mainly containing at least one selected from silver, copper, and oxides thereof.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The terminal electrode paste according to the present invention is a terminal electrode paste for co-firing, comprising nickel powder or nickel oxide powder, or conductive powder containing these as a main component, and a laminated electronic component element from a terminal portion. It is composed of a powder obtained by mixing an oxide powder for sealing intrusion of water into the body at a compounding ratio within a certain range, an organic binder and a solvent. Further, according to the present invention, a laminated electronic component using a terminal electrode paste is a laminated electronic component having a nickel internal electrode layer and an external electrode layer containing nickel or nickel as a main component, wherein the external electrode layer has a terminal portion. Is formed by applying the above-mentioned terminal electrode paste prepared by blending an oxide powder within a certain range for preventing water from entering the inside of the multilayer electronic component body, and baking by simultaneous firing. It is a thing. The oxide powder is not particularly limited, but is preferably a powder having the same sintering temperature as the laminated electronic component body and good sintering adhesion, for example, a powder having the same composition as the body. It is desirable.

Hereinafter, embodiments of the present invention will be described in detail. (Embodiment 1) First, as a conductive powder, nickel,
Copper and copper oxide powders, and as a powdered oxide for sealing the intrusion of water into the multilayer ceramic capacitor body from the terminal extraction portion, a reduction-resistant ceramic powder containing barium titanate as a main component. Were prepared, and powders were mixed in the respective mixing ratios shown in Table 1.

[0021]

[Table 1]

At this time, the weight ratio was calculated from the density of each powder so that the reduction-resistant ceramic powder had a desired volume ratio, and the powder was blended. Each of these mixed powders and a previously prepared vehicle composed of ethyl cellulose as an organic binder and α-terpineol as a solvent were kneaded with a three-roll mill to obtain each terminal electrode paste.

Separately, a 15 μm-thick green sheet comprising a reduction-resistant ceramic powder containing barium titanate as a main component and an organic binder is prepared, and nickel is formed on the green sheet to form an internal electrode layer. The conductive paste as the main component was printed in an appropriate pattern. At this time, the dry thickness of the internal electrode layer was 2.5 μm. When such a green sheet has a dielectric effective layer of 5
It was laminated and pressure-bonded so as to have 0 layers, and further cut into a predetermined shape to obtain a raw chip for a laminated ceramic capacitor.

This raw chip is chamfered to make the corners round. Then, as a first external electrode layer, each of the terminal electrode pastes previously prepared is dried, and the thickness after drying is as shown in Table 1. It applied so that it might become. The coating thickness at this time was adjusted by, for example, performing re-coating to a desired thickness while checking each time with an optical microscope.

Each of the raw chips with terminal electrodes thus obtained is debindered by holding it at 400 ° C. for 4 hours in a nitrogen atmosphere.
The main baking was performed by maintaining the temperature at 00 ° C. for 2 hours.
Thereafter, a silver paste for an external electrode is applied so as to cover the entire terminal electrode portion of the sintered body, dried, and dried in air.
By baking at 00 ° C., a second external electrode layer was formed.

Next, the defect rate of each experimental sample due to missing capacity was measured. The results are shown in Table 1. Note that the capacity loss here is one less than the design capacity value.
0% or more of low capacity. Next, a nickel layer and a solder layer were formed on the second external electrode layer by plating each for 45 minutes by an electrolytic plating method to obtain a multilayer ceramic capacitor.

Each of the multilayer ceramic capacitors obtained as described above was evaluated by an insulation resistance deterioration rate after plating, a high temperature load life test, and a high temperature moisture resistance load life test. The results are shown in Table 1. here,
The high-temperature load life test and the high-temperature moisture resistance load life test are performed by extracting a sample whose insulation resistance has not deteriorated after plating. Each test condition is a temperature of 125 ° C.
And the applied voltage is 32V, and the temperature is 85 ° C and the humidity is 85% R.
H, the applied voltage was 16 V, and the insulation resistance deterioration rate after 1000 hours was evaluated. As a criterion for determining insulation resistance deterioration, those having an insulation resistance value of 10 MΩ or less were regarded as deteriorated products. In addition, the part where the numerical value is not described in the failure occurrence rate in Table 1 is because it was determined that the part was not worthy of evaluation.

As can be seen from Table 1, Experiment No. 1
In samples 2 and 3, as the number of reduction-resistant ceramics contained in the terminal electrode paste was increased, the number of defective insulation resistances after plating was reduced. However, when the life test was performed, the samples in which the insulation resistance did not initially decrease did not decrease. Also, the deterioration of the insulation resistance was observed.

Further, the addition amount of the reduction resistant ceramic is set to 50.
When the volume% was set, several dry thicknesses of the terminal electrodes were prepared (Experiment Nos. 6 to 10) and evaluated.
With regard to Sample No. 10, although the occurrence rate was low, deterioration of the insulation resistance was observed both after plating and after the life test. In addition, when the amount of the reduction-resistant ceramic contained in the terminal electrode paste was excessively increased, that is, in Experiment Nos. 12 and 13, a sample having a capacity loss occurred.

Here, each experimental sample after plating in the present embodiment was embedded in a resin, polished to a mirror surface, and the vicinity of the element end was observed with an optical microscope. In the samples of Experiment Nos. 1 and 2, delamination was clearly observed between the multilayer ceramic body and the terminal electrode. Regarding the sample of Experiment No. 3, no clear delamination could be observed in the observation sample, but it is presumed that sufficient ceramics for sealing the end of the element body was not added to the terminal electrode paste. You.

For the sample of Experiment No. 6,
In some of the samples, it was observed that the terminal electrode was cut because the thickness was too small. For the sample of Experiment No. 10, the difference in the sintering shrinkage behavior between the ceramics and nickel in the terminal electrode was observed. Cracks were observed near the terminal electrodes of the body. In other experimental samples, no structural abnormality was found near the terminal electrode portion.

In the present embodiment, copper or copper oxide is used as the conductive powder to be mixed with the nickel powder. Similar results were obtained with the following cobalt oxides. However, if added above the above amount, each additive element diffuses into the elementary body,
Deterioration of the capacitance temperature characteristic was observed. In addition, silver was used for forming the second external electrode layer. However, even if a paste containing a powder containing at least one selected from silver, copper, and their oxides as a main component is used, it is also possible to use silver. No problem.

(Embodiment 2) First, nickel oxide, copper, and copper oxide powders as conductive powders and a sealant for sealing water from entering the multilayer ceramic capacitor body from a terminal extraction portion. As the oxide powder, a reduction-resistant ceramic powder containing barium titanate as a main component was prepared, and the powders were mixed at the compounding ratio shown in Table 2.

[0034]

[Table 2]

At this time, the weight ratio was calculated from the density of each powder so that the reduction-resistant ceramic powder had a desired volume ratio. Each of these mixed powders, and an organic vehicle made of ethyl cellulose as a binder and α-terpineol as a solvent prepared in advance were kneaded with a three-roll mill to obtain each terminal electrode paste.

Separately, a 15 μm-thick green sheet comprising a reduction-resistant ceramic powder containing barium titanate as a main component and an organic binder is prepared, and nickel is formed on the green sheet to form an internal electrode layer. The conductive paste as the main component was printed in an appropriate pattern. At this time, the dry thickness of the internal electrode layer was 2.5 μm. When such a green sheet has a dielectric effective layer of 5
It was laminated and pressure-bonded so as to have 0 layers, and further cut into a predetermined shape to obtain a raw chip for a laminated ceramic capacitor.

This raw chip was chamfered to make the corners round. Then, each of the terminal electrode pastes prepared above was used as a first external electrode layer, and the thickness after drying was as shown in Table 2. It applied so that it might become. The coating thickness at this time was adjusted by, for example, performing re-coating to a desired thickness while checking each time with an optical microscope.

Each of the raw chips with terminal electrodes thus obtained is debindered by holding it at 400 ° C. for 4 hours in a nitrogen atmosphere.
The main baking was performed by maintaining the temperature at 00 ° C. for 2 hours.
Thereafter, a silver paste for an external electrode is applied so as to cover the entire terminal electrode portion of the sintered body, dried, and dried in air.
By baking at 00 ° C., a second external electrode layer was formed.

Next, the defect rate of each experimental sample due to missing capacity was measured. The results are shown in Table 2. Note that the capacity loss here is one less than the design capacity value.
0% or more of low capacity. Next, a nickel layer and a solder layer were formed on the second external electrode layer by plating each for 45 minutes by an electrolytic plating method to obtain a multilayer ceramic capacitor.

The multilayer ceramic capacitors obtained as described above were evaluated by the insulation resistance deterioration rate after plating, the high temperature load life test, and the high temperature humidity load life test. The results are shown in Table 2. here,
The high-temperature load life test and the high-temperature moisture resistance load life test are performed by extracting a sample whose insulation resistance has not deteriorated after plating. Each test condition is a temperature of 125 ° C.
And the applied voltage is 32V, and the temperature is 85 ° C and the humidity is 85% R.
H, the applied voltage was 16 V, and the insulation resistance deterioration rate after 1000 hours was evaluated. As a criterion for determining insulation resistance deterioration, those having an insulation resistance value of 10 MΩ or less were regarded as deteriorated products. In addition, the part where the numerical value is not described in the defect occurrence rate in Table 2 is because it was determined that it was not worthy of evaluation.

As can be seen from Table 2, Experiment No. 1
In samples 6, 17, and 18, as the number of reduction-resistant ceramics contained in the terminal electrode paste was increased, the number of insulation resistance defects after plating decreased, but the life resistance test did not decrease the insulation resistance at the initial stage. Also, the deterioration of the insulation resistance was observed for the sample.

Further, the addition amount of the reduction-resistant ceramic is set to 40.
In the case of volume%, several dry thicknesses of the terminal electrodes were prepared (Experiment Nos. 21 to 25) and evaluated.
For Examples 1 and 25, although the rate of occurrence was low, deterioration of the insulation resistance was observed both after plating and after the life test. In addition, when the amount of the reduction-resistant ceramic contained in the terminal electrode paste was excessively increased, that is, in Experiment Nos. 27 and 28, a sample with a capacity loss occurred.

Here, each experimental sample after plating in the present embodiment was embedded in resin, mirror-polished, and the vicinity of the element end was observed with an optical microscope. Experiment number 1
In samples 6 and 17, delamination was clearly observed between the multilayer ceramic body and the terminal electrode. For the sample of Experiment No. 18, no clear delamination could be observed in the observation sample, but it is presumed that sufficient ceramics for sealing the end of the element body was not added to the terminal electrode paste. You.

Further, with respect to the sample of Experiment No. 21, it was observed that some of the samples had the terminal electrodes cut off because the thickness was too small. Cracks were observed in the vicinity of the terminal electrodes of the element, probably due to the difference in sintering shrinkage behavior with the reduced nickel. In other experimental samples, no structural abnormality was found near the terminal electrode portion.

In this embodiment, copper or copper oxide is used as the conductive powder to be mixed with the nickel oxide powder.
Instead, similar results were obtained with 5% by weight or less of cobalt oxide, or 4% by weight or less of cobalt or palladium with respect to nickel oxide, respectively. However, when added in more than the above amounts, each additive element diffused into the element body, and deterioration of the capacitance temperature characteristic was observed. Further, although silver was used for forming the second external electrode layer, a paste containing powder containing at least one selected from silver, copper, and their oxides as a main component may be used. Absent.

[0046]

As described above, according to the present invention, an oxide powder for complete sealing of the end of the element body is added to the terminal electrode paste at a compounding ratio within a certain range. The obtained terminal electrode paste is applied to the terminal take-out part of the raw chip of the laminated electronic component in a certain range of thickness and baked by simultaneous firing to completely prevent water from entering the element body. In addition, it is possible to manufacture a multilayer electronic component that satisfies the initial insulation resistance value and has good life characteristics with good yield.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01G 4/12 364 H01G 1/147 C (72) Inventor Hideaki Omura 1006 Ojidoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Tomoyuki Washizaki 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A nickel powder or cobalt powder containing nickel powder and nickel powder in an amount of more than 0% by weight and not more than 5% by weight,
A powder obtained by mixing one type of powder selected from copper and palladium, and a powder obtained by mixing an oxide powder so that the oxide powder is 15 to 70% by volume. Terminal electrode paste obtained by mixing and dispersing a vehicle comprising an organic binder and a solvent. 2. A mixture of nickel oxide powder or one powder selected from cobalt oxide and copper oxide in an amount of more than 0% by weight and 5% by weight or less based on the nickel oxide powder and the nickel oxide powder. A terminal obtained by mixing and dispersing a powder obtained by mixing a powder obtained by mixing the above-mentioned powder and an oxide powder so that the oxide powder becomes 10 to 60% by volume, and a vehicle comprising an organic binder and a solvent. Electrode paste. 3. A powder comprising a mixture of nickel powder or one powder selected from cobalt oxide and copper oxide of not less than 0% by weight and not more than 6% by weight based on the nickel powder; A terminal electrode paste obtained by mixing and dispersing a powder obtained by mixing an oxide powder with an organic powder in an amount of 15 to 70% by volume, and a vehicle comprising an organic binder and a solvent. 4. A powder obtained by mixing nickel oxide powder or one kind of powder selected from cobalt, copper and palladium in an amount of more than 0% by weight and 4% by weight or less based on the nickel oxide powder. A terminal electrode paste obtained by mixing and dispersing a powder obtained by mixing an oxide powder with an oxide powder in an amount of 10 to 60% by volume, and a vehicle comprising an organic binder and a solvent. 5. A multilayer electronic component comprising a nickel internal electrode layer and an external electrode layer formed from the terminal electrode paste according to claim 1. 6. A method for manufacturing a laminated electronic component including a nickel internal electrode layer, comprising: a step of chamfering a raw chip of the laminated electronic component; A step of applying and drying the terminal electrode paste according to any one of claims 1 to 4, at least once, a step of removing the green chip from the binder, and a step of firing the green chip; Forming an external electrode layer of the above. 7. The dry thickness of the terminal electrode paste applied to the terminal take-out portion of the raw chip is 5 to 50.
The method for manufacturing a laminated electronic component according to claim 6, wherein the thickness is μm. 8. The second external electrode layer is formed by applying and baking a paste mainly containing at least one selected from silver, copper, and oxides thereof. The manufacturing method of the laminated electronic component as described in the above.