JPH11168024A - Manufacturing method of multilayer ceramic electronic component - Google Patents

Abstract

(57) [Problem] To provide a method for manufacturing a multilayer ceramic electronic component which prevents occurrence of short-circuit failure and delamination failure in a multilayer ceramic electronic component compatible with thin layers and high lamination. SOLUTION: It comprises a dense first ceramic sheet 3 composed of a ceramic powder, a binder and a plasticizer, a second ceramic sheet 2 having the same composition and a higher porosity than the first ceramic sheet, and an internal electrode 4. In the laminate,
The internal electrodes 4 are printed on the first ceramic sheet 3 and the second ceramic sheet 2 is laminated on the printed internal electrodes 4. The green laminated body produced by repeatedly repeating the first ceramic sheet 3, the internal electrode 4, and the second ceramic sheet 2 in a plurality of layers in this manner is cut into a predetermined shape, and then fired at a predetermined temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer ceramic electronic component having internal electrodes, such as a multilayer ceramic capacitor (hereinafter referred to as a multilayer capacitor).

[0002]

2. Description of the Related Art The prior art will be described by taking a multilayer capacitor as an example.

FIG. 4 is a partial sectional view of a green chip of a conventional multilayer capacitor, and FIG. 5 is a sectional view of a conventional multilayer capacitor. 4, 11 is a green chip, 12 is a ceramic sheet, 13 is an internal electrode, 14 is an ineffective layer, and in FIG. 5, 15 is an external electrode and 16 is a multilayer capacitor.

In a conventional multilayer capacitor 16, an internal electrode 13 is printed on a ceramic sheet 12 made of a ceramic powder, a binder, and a plasticizer, and the ceramic sheet 12 is further laminated on the internal electrode 13, and then laminated. The internal electrode 13 is printed on the ceramic sheet 12 such that the internal electrode 13 is printed on the ceramic sheet 12.
Green chips 11 formed by alternately laminating a plurality of layers 3
Was fired at a predetermined temperature, and then external electrodes 15 were provided at both ends.

The internal electrodes 13 are printed so as to be electrically connected alternately to the external electrodes 15 at both ends.

[0006]

In the conventional multilayer capacitor 16 as described above, the ceramic sheet 12 needs to be made thinner as the size of the ceramic sheet 12 becomes smaller due to the increase in size and capacity.
In this case, there is a problem that the internal electrode 13 paste seeps and a short circuit occurs between the internal electrodes 13. As a countermeasure, if the ceramic sheet 12 is densified to prevent penetration of the internal electrode 13 paste, the compressibility of the ceramic sheet 12 is reduced. , The adhesiveness between the laminated ceramic sheets 12 was reduced, and this was one of the causes of the occurrence of internal structural defects (delamination).

The present invention solves the above-mentioned problems and prevents short-circuiting between the internal electrodes 13 even in thin layers and high lamination.
It is another object of the present invention to provide a method for manufacturing a multilayer ceramic electronic component free from delamination failure.

[0008]

In order to solve the above-mentioned problems, the present invention provides a laminated body in which ceramic layers and internal electrodes are alternately laminated, wherein the ceramic layer comprises a dense first ceramic sheet; The first ceramic sheet is composed of a second ceramic sheet having a higher porosity than the first ceramic sheet, and the first ceramic sheet, the internal electrodes, and the second ceramic sheet are repeatedly laminated in the above-described order to form a plurality of layers. An object of the present invention is to provide a multilayer ceramic electronic component which prevents short circuit between internal electrodes and does not cause delamination.

[0009]

The invention according to claim 1 is a laminate in which ceramic layers and internal electrodes are alternately laminated,
The ceramic layer is composed of a dense first ceramic sheet and a second ceramic sheet having a higher porosity than the first ceramic sheet, wherein the first ceramic sheet, the internal electrodes, and the second ceramic sheet. A method for producing a multilayer ceramic electronic component, comprising stacking a plurality of layers of sheets repeatedly in the order described above, and further providing an ineffective layer made of a second ceramic sheet on the upper and lower outermost layers,
Since the ceramic layer is composed of a dense first ceramic sheet and a second ceramic sheet having a higher porosity than the first ceramic sheet, the thickness steps of the internal electrodes when a predetermined number of layers are stacked are reduced by a gap. While absorbing with the second ceramic sheet having a large ratio, the penetration of the internal electrode paste is prevented by the dense first ceramic sheet, so that a short circuit between the internal electrodes is prevented, and the occurrence of delamination is also prevented. Can be prevented.

According to a second aspect of the present invention, the difference in density between the first ceramic sheet and the second ceramic sheet is at least 0.4 g / cm ³ or more.
Wherein the density difference between the first ceramic sheet and the second ceramic sheet is at least 0.4 g / cm ³ or more,
The thickness step of the internal electrode printed on the first ceramic sheet is absorbed by the second ceramic sheet having high compressibility, and the occurrence of delamination is prevented. In addition, since the density difference is 0.4 g / cm ³ or more, the printed internal electrode paste is formed without being absorbed by the second ceramic sheet, so that a short circuit does not occur.

According to a third aspect of the present invention, the density of the first ceramic sheet and the second ceramic sheet having the same composition comprising a ceramic powder, a binder and a plasticizer is determined by adding the binder and the plasticizer to the ceramic powder. 2. The method according to claim 1, wherein the mixing and dispersing time is adjusted by controlling the mixing and dispersing time when performing the mixing and dispersing with a ball mill.
Or a method of manufacturing a multilayer ceramic electronic component according to 2, wherein the desired density can be easily obtained by controlling the mixing and dispersing time, and the compositions of the first ceramic sheet and the second ceramic sheet are made the same. Therefore, the adhesion between the ceramic sheets is good, and the occurrence of delamination can be prevented.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a partial cross-sectional view of a green chip of a multilayer capacitor of the present invention, FIG. 2 is a cross-sectional view showing a laminating method in a manufacturing process, and FIG. FIG. In FIG. 1, 1 is a green chip, 2 is a second ceramic sheet having a large porosity, 3 is a dense first ceramic sheet, 4 is an internal electrode, and 5 is an ineffective layer. In FIG. 2, 6 is a PET film, 7 is a fixed film, and 8 is a base plate. In FIG. 3, 9 is an external electrode, and 10 is a multilayer capacitor.

First, for 100 parts by weight of a ceramic powder containing barium titanate as a main component, 8 parts by weight of a polyvinyl butyral resin as a binder, 3.6 parts by weight of dibutyl phthalate as a plasticizer, and 53 parts by weight of butyl acetate as a solvent. After the addition, the mixture is mixed and dispersed by a ball mill to prepare a slurry. At this time, three kinds of slurries were prepared by changing the mixing and dispersing time to 24 hours, 60 hours, and 120 hours.

Next, each of the three types of slurries is
Using a 20 μm gap applicator, the composition was applied onto a PET film 6 which had been subjected to a release material treatment, and dried to produce three types of ceramic sheets. Table 1 shows the characteristics of the produced ceramic sheets.

[0015]

[Table 1]

As shown in Table 1, when mixing and dispersing for 120 hours despite the use of the applicator having the same gap, the dispersion of the ceramic powder progresses, and the sheet thickness becomes thin and the density becomes high. The porosity is small and dense. On the other hand, when the mixing and dispersion are performed for 24 hours, the dispersion of the ceramic powder is small, the sheet thickness is large, the density is low, and the porosity is large. In addition, it can be seen that the average value obtained when the mixed dispersion was performed for 60 hours was close to the average value obtained when the mixed dispersion was performed for 24 hours and the time when the mixed dispersion was performed for 120 hours. Therefore, by changing the mixing and dispersing time of the slurry, it is possible to produce a ceramic sheet having a desired initial density and porosity, so that the density of the ceramic sheet can be adjusted by controlling the mixing and dispersing time. is there.

The porosity in the table is calculated based on the theoretical closest packing density calculated assuming that the density of the ceramic powder is 6.00 g / cm ³ and the density of the binder and the plasticizer is 1.10 g / cm ³ .
It was determined from 10 g / cm ³ . The density after pressurization was measured after applying a pressure of 70 kg / cm ² at a temperature of 110 ° C. to the dried ceramic sheet, and the compressibility was the shrinkage of the thickness before and after heating and compression under the above conditions. It is shown.

Of the three types of ceramic sheets thus obtained, those mixed and dispersed for 120 hours were used as the first ceramic sheet 3 and those mixed and dispersed for 24 hours were used as the second ceramic sheet 2. As shown in FIG. 2, an ineffective layer 5 formed by laminating 24 second ceramic sheets 2 is provided on a polyester fixing film 7 adhered to a metal base plate 8, and then the first ceramic A sheet on which the internal electrodes 4 are printed on the surface of the sheet 3 is laminated by heating.
Next, the second ceramic sheet 2 is heated and laminated on the first ceramic sheet 3 so as to be adhered thereto. After that, the first ceramic sheet 3 and the second ceramic sheet 2 on which the internal electrodes 4 are sequentially printed are repeatedly heated and laminated so that the internal electrodes 4 have 120 layers.
Are laminated by heating the ineffective layer 5 to form a green chip 1, which is baked at a predetermined temperature, and external electrodes 9 are provided at both ends as shown in FIG. 3 to obtain a multilayer capacitor 10. The results obtained by examining the short-circuit occurrence rate and the delamination occurrence rate of the thus-obtained sample are shown as Sample 1 in (Table 2).

Also, as the first ceramic sheet 3, 1
A sample 1 was prepared by mixing and dispersing for 20 hours and using a mixture that was mixed and dispersed for 60 hours as the second ceramic sheet 2.
The multilayer capacitor 10 manufactured in the same manner as that described above is used as a sample 2.

FIG. 4 shows a conventional example for comparison.
The green chip 11 obtained by repeatedly heating and laminating the ceramic sheet 12 prepared from the slurry mixed and dispersed for 120 hours and the internal electrode 13 to laminate the internal electrode 13 into 120 layers as shown in FIG. Later, FIG.
As shown in Table 2, a multilayer capacitor 16 manufactured by providing external electrodes 15 at both ends is shown as Sample 3 in Table 2.

Further, a multilayer capacitor 16 prepared in the same manner as Sample 3 using a ceramic sheet 12 prepared from a slurry mixed and dispersed for 60 hours was used as a sample 4 and a ceramic sheet 12 prepared from a slurry mixed and dispersed for 24 hours. The multilayer capacitor 16 manufactured in the same manner as the sample 3 is described as a sample 5 in (Table 2).

In the samples 1 to 5 produced as described above, the shape of the green chip 1 or 11 is set to 3.
The dimensions were 7 x 1.9 x 1.4 mm in thickness, and firing was performed at 1300 ° C for 1 hour.

[0023]

[Table 2]

As shown in Table 2, a dense first ceramic sheet 3 prepared from a slurry mixed and dispersed for 120 hours and a second ceramic sheet 2 having a large porosity prepared from a slurry mixed and dispersed for 24 hours were used. In the case of the sample 1 in which the combination of (1) and (2), short-circuit and delamination failure did not occur at all. On the other hand, in the case of Sample 2 in which the first ceramic sheet 3 was the same as Sample 1 and the second ceramic sheet 2 was prepared from a slurry mixed and dispersed for 60 hours, short-circuit failure occurred. No, but delamination failure has occurred. This is 24
As compared with the ceramic sheet 2 of the sample 1 mixed and dispersed for a time,
The ceramic sheet 2 of Sample 2 produced from the slurry mixed and dispersed for 60 hours has a high density and a low porosity. For this reason, it is considered that the compression ratio at the time of heating and laminating becomes small, and it becomes difficult to absorb the thickness step of the internal electrode 4, and delamination has occurred. Therefore, in order to suppress the short-circuit defect and sufficiently absorb the thickness step of the internal electrode 4, the density difference between the dense first ceramic sheet 3 and the second ceramic sheet 2 having a large porosity should be at least 0.4 g. / Cm ³ is preferably provided.

On the other hand, the sample 3 using only one type of ceramic sheet 12 according to the conventional manufacturing method manufactured as a comparative example has a high density, a high porosity, Since the compression ratio is low, short-circuit failure of the internal electrode 13 does not occur, but the thickness difference of the internal electrode 13 cannot be absorbed, and delamination failure frequently occurs, which is not preferable. In the case of Sample 4, the ceramic sheet 1 used in comparison with Sample 3 was used.
2, the mixing and dispersion time is as short as 60 hours, so the density is small,
Although the occurrence of the delamination failure is reduced by an amount corresponding to the increase in the compression ratio at the time of heating and laminating, the shortage failure occurs due to the increased porosity. Further, in the case of the sample 5, since the mixing and dispersing time of the used ceramic sheet 12 is even shorter as 24 hours, the density is small, and the occurrence of delamination failure can be prevented by an amount corresponding to the increase in the compression ratio during heating and lamination. Short circuit failures occur more frequently as the porosity increases, which is not appropriate.

From the above results, the ceramic layer between the internal electrodes 4 is composed of two layers in which the dense first ceramic sheet 3 and the second ceramic sheet 2 having a higher porosity than the first ceramic sheet 3 are combined. With the configuration, the penetration of the internal electrode 4 paste is prevented by the dense first ceramic sheet 3, the occurrence of short-circuit failure of the internal electrode 4 is prevented, and the thickness step of the internal electrode 4 is reduced by the first ceramic sheet 3. Since it can be absorbed by the second ceramic sheet 2 having a larger porosity than that of the second ceramic sheet 2, it is possible to manufacture the multilayer capacitor 10 that can prevent the delamination failure.

By setting the density difference between the first ceramic sheet 3 and the second ceramic sheet 2 to 0.4 g / cm ³ or more, the thickness difference of the internal electrodes 4 can be sufficiently absorbed.
More preferred.

[0028]

As described above, according to the present invention, in a laminated ceramic electronic component in which ceramic layers and internal electrodes are alternately laminated, the ceramic layers are formed by a dense first ceramic sheet and a first ceramic sheet. Since it is composed of the second ceramic sheet having a large porosity, when the first ceramic sheet, the internal electrode, and the second ceramic sheet are sequentially and repeatedly laminated in a plurality of layers, the penetration of the internal electrode paste is dense A single ceramic sheet prevents the occurrence of short-circuit failure and suppresses the occurrence of short-circuit failure, and the thickness difference of the internal electrode is absorbed by the second ceramic sheet having a large porosity. Can be provided.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a green chip of a multilayer capacitor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a lamination method in the manufacturing process.

FIG. 3 is a sectional view of the multilayer capacitor.

FIG. 4 is a partial cross-sectional view of a green chip of a conventional multilayer capacitor.

FIG. 5 is a sectional view of the multilayer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Green chip 2 Second ceramic sheet 3 First ceramic sheet 4 Internal electrode 5 Invalid layer 6 PET film 7 Fixed film 8 Base plate 9 External electrode 10 Multilayer capacitor

Claims (3)

[Claims] 1. A laminated body in which ceramic layers and internal electrodes are alternately laminated, wherein the ceramic layer is a dense first ceramic sheet and a second ceramic sheet having a higher porosity than the first ceramic sheet. A ceramic sheet, the first ceramic sheet, the internal electrode, and the second ceramic sheet are repeatedly laminated in a plurality of layers in the above order, and furthermore, an inactive layer formed of the second ceramic sheet is formed on the upper and lower outermost layers. A method for manufacturing a multilayer ceramic electronic component, comprising: 2. The method according to claim 1, wherein a density difference between the first ceramic sheet and the second ceramic sheet is at least 0.4 g / cm ³ or more. 3. The density of the first ceramic sheet and the second ceramic sheet having the same composition comprising a ceramic powder, a binder and a plasticizer is determined by adding the binder and the plasticizer to the ceramic powder and mixing and dispersing the mixture by a ball mill. 3. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the mixing and dispersing time is adjusted by controlling the mixing and dispersing time.