JP2764512B2 - Paste for internal electrode of ceramic component and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste for an internal electrode of a multilayer ceramic component and a method for producing the same, and more particularly, to a reduction in the thickness, prevention of defects and cost reduction of an internal electrode used in a small and high-capacity multilayer ceramic chip capacitor. And a method for producing the same.

[0002]

2. Description of the Related Art A conventional paste for an internal electrode is prepared by adding a zirconia ball, palladium powder, an organic metal such as organoplatinum (platinum resinate) and organorhodium (rhodium resinate) and a solvent to a polypot and performing ball mill dispersion. It is manufactured by discharging a medium from a polypot to a grinder, charging a binder, and mixing. As a specific example, 225 g of 5 mmφ zirconia balls are put into a polypot having a capacity of 100 ml, and palladium powder 5 is further added.
0 g, organic platinum 5.8 g, organic rhodium 1.2 g, solvent 1
2 g was charged, the rotation speed of the polypot was set to 60 rpm, and the mixture was dispersed in a ball mill for 168 hours (7 days). After that, the mixture was discharged from the polypot to a grinder, and a binder obtained by dissolving 10% by weight of ethyl cellulose in a solvent was used. It is put into a crusher, and a dispersion medium and a binder are mixed to form a paste.

Conventionally, palladium powder having a particle size of 0.3 μm or less and having high dispersibility has been used as a paste in order to reduce the thickness of the internal electrode of the multilayer ceramic component. There was a problem in the case of multilayering.

Further, in order to suppress the occurrence of defects, the palladium oxidative expansion is increased by using palladium powder of good crystallinity having a half-width of a diffraction peak by X-ray diffraction having a particle diameter of 0.5 μm or more and 0.6 or less. Al ₂ O ₃ , SiO _2, etc. used as a co-material of an organic metal or a noble metal resinate or a dielectric ceramic were added and made into a paste, but when this method was used, the density when dried became low. It is very difficult to reduce the thickness of the internal electrode film, and defects have occurred due to unevenness of the internal electrode.

By the way, palladium powder having a particle size of 0.3 μm or less has a high activity, and starts oxidizing at a low temperature of 300 ° C. to expand in volume. The strength (shape retention) of barium titanate (BaTiO ₃ ) or strontium titanate (SrTiO ₃ ) used in a multilayer ceramic capacitor is lowest around 250 ° C., and increases as the temperature rises. Since the temperature at which the palladium powder starts to oxidize and expand is 300 ° C., which is a temperature at which the shape retaining force of the multilayer ceramic capacitor is extremely weak, cracks are likely to occur. Therefore, it was very difficult to make the internal electrode layers multilayer.

On the other hand, in the case of palladium powder of good crystallinity having a half-width of a diffraction peak by X-ray diffraction having a particle size of 0.5 μm or more and 0.6 or less, the oxidation initiation temperature is as high as 600 ° C. Further, when an organic metal is added to the palladium powder, expansion due to oxidation of palladium is suppressed, and
When the temperature is higher than 00 ° C., the multilayer ceramic capacitor has a high shape-retaining force, and thus the ceramic capacitor body is hardly cracked.

However, it is necessary to increase the thickness of the internal electrode paste to 4 to 5 μm immediately after the screen printing in a non-dried state. The step due to the unevenness of the internal electrode has a great effect, and when fired, the adhesion strength between the green sheets is reduced, which may cause cracks.

Further, Al ₂ O ₃ , SiO ₂ used as a co-material of an organic metal such as organoplatinum and organorhodium and a dielectric ceramic for suppressing oxidation and expansion of palladium powder.
Similarly, when an inorganic substance such as the above is added to form a paste, the paste density at the time of drying is similarly greatly reduced, so that cracks may be generated due to steps generated at the time of drying.

[0009]

SUMMARY OF THE INVENTION The present invention relates to the problems of the prior arts, namely, the difficulty in forming multilayered internal electrode layers, the occurrence of irregularities, and the large decrease in density after drying. It is an object to solve the problems of the paste for internal electrodes of components and the method of manufacturing the same.

[0010]

In order to solve the above-mentioned problems, in the present invention, an organic metal and dibutylaminopropylamine and diethylaminopropylamine are added to an internal electrode paste as additives for suppressing the oxidation and expansion of palladium. , Dimethylaminopropylamine, that is, an internal electrode of a multilayer ceramic component obtained by adding a common material of an organic metal and a ceramic body such as platinum, gold, palladium, rhodium, chromium, calcium, and titanium to palladium powder. Paste composition, and 10 to 25 parts by weight of dibutylaminopropylamine, or 15 to 30 parts by weight of diethylaminopropylamine, or 20 to 40 parts by weight of dimethylaminopropylamine based on the organic metal. Characterized by the internal The invention is characterized in that it is a "paste for" and "a palladium powder and one of the organic metal and the ceramic layer body and one of the dialkylaminopropylamine and a solvent are weighed, and the weighed one is stirred and dispersed, and then an appropriate amount. A method for producing a paste for a ceramic internal electrode, comprising mixing with a binder.

[0011]

[Function] By increasing the drying density of the internal electrode paste, the thickness of the internal electrode after screen printing can be reduced,
Cracks caused by steps of the internal electrodes are suppressed.
In addition, by using palladium powder having good crystallinity and an additive that suppresses oxidative expansion of palladium, generation of cracks during firing due to oxidative expansion of palladium is prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each of the methods tested for inventing the paste for a ceramic internal electrode and the method for producing the paste for a ceramic internal electrode of the present invention will be described together with data.

Example 1 First, when the time when dibutylaminopropylamine was added to the conventional production method was added at the time of ball mill dispersion, when it was added when the dispersion medium and the binder were mixed by a crusher, paste was formed. When the paste was added after the addition, and when the addition was not performed, the following procedure was performed, and the paste density of the thus obtained dried paste was measured. When measuring the paste density during drying, spread the paste evenly on the film so that there is no unevenness,
A palladium sheet was prepared by drying at 110 ° C. for 90 minutes, the sheet was punched out with a 20 mmφ punch, the weight and the film thickness were measured, and the density was calculated.

The amount of dibutylaminopropylamine added at this time was 10 parts by weight based on 100 parts by weight of the total of organoplatinum and organorhodium, and the amount of the solvent was reduced by an amount corresponding to the weight of dibutylaminopropylamine. the above~
The method will be specifically described.

A solvent was added to the palladium powder, the organic metal and dibutylaminopropylamine, and the mixture was dispersed for 168 hours using a ball mill. Then, a binder was added, and the mixture was mixed with a crusher to form a paste. The density of the thus obtained internal electrode paste at the time of drying was 5.0 to 5.5 g.
/ Cm ³ .

A solvent was added to the palladium powder and the organic metal, and the mixture was dispersed for 168 hours using a ball mill. Then, a binder and dibutylaminopropylamine were added and mixed with a mortar to form a paste. The dry density of the internal electrode paste obtained in this manner is 4.5 to 5.0.
g / cm ³ .

A solvent was added to the palladium powder and the organic metal, and the mixture was dispersed for 168 hours using a ball mill. Then, a binder was added and mixed with a grinder, and dibutylaminopropylamine was added to form a paste. The dry density of the internal electrode paste thus obtained was 4.0 to 5.0 g / cm ³ .

A solvent was added to the palladium powder and the organic metal, and the mixture was dispersed for 168 hours using a ball mill. Then, a binder was added, and the mixture was mixed with a crusher to form a paste. The dry density of the internal electrode paste thus obtained was 3.5 to 4.0 g / cm ³ .

From these results, when the method of adding dibutylaminopropylamine during dispersion in a ball mill, the density of the paste when dried is the highest. Further, regardless of the method of adding dibutylaminopropylamine, the paste density at the time of drying becomes higher as compared with the case without the addition.

Next, when the amount of dibutylaminopropylamine added was changed in the range of 0.1 to 40 parts by weight with respect to 100 parts by weight of the total amount of organoplatinum and organorhodium in the production method, drying of the paste was performed. The density at the time was measured in the same manner and the pH was measured with a PH meter. In addition, as a comparative example, a sample to which no organic metal (organoplatinum, organorhodium) and dibutylaminopropylamine were added was also measured. Table 1 shows the measurement results.

[0021]

[Table 1]

As shown in this table, as the addition amount of dibutylaminopropylamine increases, the density of the internal electrode paste at the time of drying increases, and it is the maximum when the addition amount is in the range of 10 to 25 parts by weight. With the above, the density becomes slightly small, and the density of the internal electrode paste when dried becomes large even when the organic metal and dibutylaminopropylamine are not added.

When the organic metal is added, the density of the internal electrode paste during drying decreases. This means that when the binder ethyl cellulose and the organic metal are mixed, coated on a film, and dried, the state is observed with a scanning electron microscope. This was also observed from the fact that the addition amount of dibutylaminopropylamine increased and a uniform film was formed. Since the non-uniformity causes the density of the internal electrode paste to be reduced when dried, the uniformity can increase the density of the internal electrode paste when dried.

The PH of the paste is 1 or less because the pH of the organic metal is 1 or less, and the pH of the sample No. 1 to which only the organic metal is added is 1-2, and the pH of dibutylaminopropylamine is 8 or more. Therefore, as the amount of dibutylaminopropylamine added increases, it becomes closer to 7 which is neutral. Note that the reason why the pH of the internal electrode paste becomes 1-2 by the addition of the organic metal is that the pH of the organic metal is 1 or less, and that the pH becomes neutral by the addition of dibutylaminopropylamine. The amine has a pH of 8 or more, and neutralizes the acidity of the organic metal.

In order to observe the occurrence of cracks and the like,
After a dielectric slurry is formed into a sheet having a thickness of 15 μm on a base film, the internal electrode paste having the composition shown in Table 1 is printed by screen printing and dried, and 120 layers are laminated. The chip was cut into pieces.

The paste-free portion (non-lamination) generated on the cut surface of the chip after cutting was observed with a stereo microscope of 40 × magnification. Next, this was debindered and fired, and 1000 cracks generated in the fired chip were observed with a stereoscopic microscope of 40 × magnification. Further, the chip was embedded in an epoxy resin and polished until the internal electrode layer was visible, and 100 gaps (delamination) generated on the polished surface of the chip were observed with a metal microscope of 400 magnifications. Table 2 shows the results. In addition, the film thickness after printing and drying in the table is a value measured by a surface roughness meter.

[0027]

[Table 2]

As shown in Table 2, when the amount of dibutylaminopropylamine relative to 100 parts by weight of organoplatinum and organorhodium as the organic metal is 5 parts by weight or more, the occurrence of non-lamination is suppressed. If there is, delamination will occur. Therefore, the amount of dibutylaminopropylamine necessary to suppress the occurrence of non-lamination and delamination is 5 to 25 parts by weight based on 100 parts by weight of organoplatinum and organorhodium as the organic metal.

Table 3 shows the results of examining the variation in capacity when the amount of palladium deposited during printing was changed with respect to the paste dry density according to the amount of dibutylaminopropylamine. Note that the number of samples for which the capacitance was measured was 50, and when the unbiased variance of the capacitance was σ _n-1 and the average value was E, the variation coefficient was A =
_Let 3σ _n-1 / E. ○ indicates A ≦ 5%, Δ indicates 5 <A ≦
10%, x mark 10% <A.

[0030]

[Table 3]

According to Table 3, when the density during drying of the paste is kept constant, the dispersion of the capacity is smaller when the amount of palladium deposited is larger, but when the amount of deposited palladium is kept constant, the drying time of the paste is lower. The larger the density of the sample, the smaller the variation in capacity. In addition, the larger the paste density at the time of drying, the smaller the variation in capacity even if the amount of palladium deposited is reduced. In this case, the addition amount of dibutylaminopropylamine may be 5 to 25 parts by weight, but the range of 10 to 25 parts by weight is a practical addition amount.

In summary, the amount based on the organic metal is 10 to 25 parts by weight in the case of dibutylaminopropylamine, and 15 to 30 parts by weight in the case of diethylaminopropylamine.
Parts by weight, in the case of dimethylaminopropylamine, 20 to
It can be said that an optimum ceramic component internal electrode paste can be obtained when the addition amount is 40 parts by weight.

In the production method of Example 2, the paste obtained when the addition amount of diethylaminopropylamine was changed in the range of 0.1 to 50 parts by weight based on 100 parts by weight of the total amount of organoplatinum and organorhodium was used. The dried density was measured in the same manner and the pH was measured with a PH meter. Table 4 shows the measurement results.

[0034]

[Table 4]

As shown in this table, as the amount of diethylaminopropylamine added increases, the density of the internal electrode paste at the time of drying increases, and the maximum value is obtained in the range of 15 to 30 parts by weight. Further, PH is similar to that of dibutylaminopropylamine, and approaches 7 which is neutral as the added amount increases. In order to observe the state of generation of cracks and the like, observation was performed in the same manner as for the internal electrode paste to which dibutylaminopropylamine was added. Table 5 shows the results.

[0036]

[Table 5]

As shown in Table 5, when the amount of diethylaminopropylamine is at least 10 parts by weight based on 100 parts by weight of the total amount of organoplatinum and organorhodium, the occurrence of non-lamination is suppressed and the amount is at least 40 parts by weight. And delamination occurs. Therefore, the amount of diethylaminopropylamine required to suppress the occurrence of non-lamination and delamination is 10 to 30 parts by weight based on 100 parts by weight of the total amount of organoplatinum and organorhodium. Next, Table 6 shows the results of examining the capacity variation when the amount of palladium deposited during printing was changed with respect to the paste dry density according to the amount of diethylaminopropylamine.

[0038]

[Table 6]

According to Table 6, the addition amount of diethylaminopropylamine may be 10 to 30 parts by weight,
The range of 0 parts by weight is a practical addition amount.

In the production method of Example 3, the paste was prepared by changing the addition amount of dimethylaminopropylamine in the range of 0.1 to 50 parts by weight based on 100 parts by weight of the total amount of organoplatinum and organorhodium. Was dried in the same manner as above, and the pH was measured with a PH meter. Table 7 shows the measurement results.

[0041]

[Table 7]

As shown in this table, as the amount of dimethylaminopropylamine added increases, the density of the internal electrode paste at the time of drying increases, and the maximum value is obtained in the range of 20 to 4 parts by weight. Also, PH becomes closer to neutral 7, which is the same as that of dibutylaminopropylamine, when the amount of addition is increased. In order to observe the state of generation of cracks and the like, observation was performed in the same manner as for the internal electrode paste to which dibutylaminopropylamine was added. Table 8 shows the results.

[0043]

[Table 8]

As shown in Table 8, when the amount of dimethylaminopropylamine is 15 parts by weight or more with respect to 100 parts by weight of the total amount of organoplatinum and organorhodium, the occurrence of non-lamination is suppressed. If there is, delamination will occur. Therefore, the amount of dimethylaminopropylamine required to suppress the occurrence of non-lamination and delamination is 15 to 40 parts by weight based on 100 parts by weight of the total amount of organoplatinum and organorhodium.

Next, Table 9 shows the results of examining the capacity variation when the amount of palladium deposited during printing was changed with respect to the paste dry density according to the amount of dimethylaminopropylamine.

[0046]

[Table 9]

According to Table 9, the addition amount of dimethylaminopropylamine may be 15 to 40 parts by weight,
The range of parts by weight is a practical addition amount.

The paste for an internal electrode of the present invention has been described for a multilayer ceramic capacitor, but is applied to a multilayer ceramic component such as a multilayer varistor and a multilayer inductor composed of a ceramic layer and internal electrodes.

[0049]

According to the structure of the present invention, it is possible to increase the dry density of the paste for internal electrodes, thereby reducing the thickness of the internal electrodes after screen printing. Thus, the step caused by the step is reduced, and even if the internal electrodes are multilayered, the crack caused by the step can be suppressed. In addition, by using palladium powder having good crystallinity, by adding dibutylaminopropylamine or the like that suppresses oxidative expansion of palladium to form a paste, the oxidation and expansion of palladium are suppressed, and cracking during firing is prevented. You.

Therefore, it is possible to make the internal electrodes thinner, so that a small-sized multilayered and highly reliable laminated electronic component can be obtained. Further, the internal electrodes are formed of a palladium layer occupying more than half the cost of the laminated component. Cost reduction is possible by thinning.

Continuing from the front page (72) Inventor Takaya Ishigaki TDK Corporation, 1-13-1 Nihonbashi, Chuo-ku, Tokyo (58) Field surveyed (Int. Cl. ⁶ , DB name) H01G 4/12

Claims (5)

(57) [Claims] 1. A paste composition for an internal electrode of a laminated ceramic component, wherein a palladium powder is added with a common material of an organic metal such as platinum, gold, palladium, rhodium, chromium, calcium, titanium and a ceramic body, further comprising: A paste for an internal electrode of a ceramic part, wherein 10-25 parts by weight of dibutylaminopropylamine is added to an organic metal. 2. A paste composition for an internal electrode of a multilayer ceramic component, wherein a palladium powder is added with a common material of an organic metal such as platinum, gold, palladium, rhodium, chromium, calcium, titanium and a ceramic body, and further comprising: A paste for an internal electrode of a ceramic part, wherein 15-30 parts by weight of diethylaminopropylamine is added to an organic metal. 3. A paste composition for an internal electrode of a multilayer ceramic component, wherein a palladium powder is added with a common material of an organic metal such as platinum, gold, palladium, rhodium, chromium, calcium, titanium and a ceramic body, and further comprising: A paste for an internal electrode of a ceramic component, wherein 20-40 parts by weight of dimethylaminopropylamine is added to an organic metal. 4. The paste density in a dry state is 4.0.
4. The paste for an internal electrode of a ceramic electronic component according to claim 1, wherein the paste is in the range of 6.0 to 6.0 g / cm < ² > and the pH is in the range of 6 to 7. 5. A method of weighing one of a palladium powder, an organic metal and a ceramic layer and a dialkylaminopropylamine and a solvent, stirring and dispersing the weighed material, and then mixing the weighed material with an appropriate amount of a binder. Manufacturing method for internal electrode paste.