JPH11265835A - Laminated electronic component, their manufacture, and ceramic powder for the component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of the reliability, such as the life time characteristic, etc., of laminated electronic components due to such cases in that the adhesion of ceramic green sheets becomes insufficient at a part where no conductive pattern is printed, because the adhering amount of the green sheets become insufficient, and delamination is apt to occur among the sheets after baking. SOLUTION: In a laminated electronic component manufacturing method, ceramic power containing porous ceramic particles is used as the raw material of ceramic green sheets. The ceramic forming the ceramic layer of the electronic components contains the porous ceramic particles. It is preferable that the volumetric ratio of the pores be adjusted to the whole body of each porous particles to 5-10 vol.%. As the material of the porous ceramic particles BaTiO3 , CaTiO3 , BaZrO3 , PbTiO3 , or Ba(Ti, Zr)O3 are included.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer electronic component having a ceramic layer and an internal conductive layer, such as a multilayer ceramic capacitor, a multilayer piezoelectric component, a multilayer inductor, a multilayer filter, a ceramic multilayer substrate, and a method of manufacturing the same. The present invention relates to a ceramic powder for a laminated electronic component used for forming a ceramic layer of a laminated electronic component.

[0002]

2. Description of the Related Art In general, a multilayer electronic component of this kind is formed by printing a large number of conductive patterns for forming internal conductive layers such as internal electrodes on the surface of a ceramic green sheet in a matrix.
A plurality of the ceramic green sheets are stacked, cut into chips for each conductive pattern, and the obtained chip-shaped laminate is fired and sintered at a high temperature of, for example, about 1200 ° C., and external electrodes are formed thereon. It is manufactured by forming.

Here, as shown in FIG. 1A, the conductive pattern 10 is printed on a part of the surface of the ceramic green sheet 12, and the conductive pattern 10 and the ceramic pattern of the printed portion of the ceramic green sheet 12 are connected to each other. Green sheet 1
Since the integrated thicknesses of the 2,12 (t ₁ + 2t ₂₎ is thicker integrated thickness of the ceramic green sheets 12 and 12 of the unprinted portion of the conductive pattern 10 from the (2t ₂₎ by t _1, FIG. As shown in FIG. 1 (b), simply stacking the ceramic green sheets 12 on which the conductive patterns 10 are printed simply causes t ₁ between the ceramic green sheets 12 where the conductive patterns 10 are not printed.
Only a gap is formed and does not adhere.

Therefore, in the above-described method for manufacturing a laminated electronic component, the laminated ceramic green sheets 12, 1
2 is pressed by applying a large pressure in the thickness direction before cutting the conductive patterns 2 into chips for each conductive pattern 10.

[0005] The laminated ceramic green sheets 12
Is pressed in the thickness direction, as shown in FIG. 1C, first, the adjacent ceramic green sheets 12 and the conductive patterns 10 are firmly adhered to each other by lamination, and then the conductive patterns 10 are printed. The portion of the ceramic green sheet 12 is compressed and slightly flows toward the ceramic green sheet 12 where the conductive pattern 10 is not printed, as indicated by the arrow A, and the portion where the conductive pattern 10 is printed is printed. The accumulated thickness of the non-existing portions is equal to t ₃ , and the adjacent ceramic green sheets 12, 12 adjacent to the portions where the conductive pattern 10 is not printed are firmly adhered.

[0006] With the recent trend toward miniaturization and higher density of electronic circuits, multilayer electronic components are also required to have smaller sizes and larger capacities. In order to reduce the size and capacity of the multilayer electronic component, attempts have been made to increase the number of stacked ceramic green sheets and conductive patterns.

Here, in order to increase the number of stacked ceramic green sheets and conductive patterns, it is conceivable to reduce the thickness of the conductive patterns and the thickness of the ceramic green sheets. However, if the conductive pattern is made too thin, the electrical resistance of the formed internal electrodes and the like increases, and Q deteriorates.
There is a limit in thinning the conductive pattern. Therefore, thinning of ceramic green sheets has been mainly studied.

[0008]

However, as the thickness of the ceramic green sheet is reduced, as shown in FIGS. 2 (a) and 2 (b), the ceramic green sheet 1 becomes thinner.
The ratio of the thickness of t ₅ of the conductive pattern 10 for 2 thickness t ₄ increases, as shown in FIG. 2 (c), during the crimping, the sheet 12 of the portion where the conductive pattern 10 is printed Need to flow a large amount as shown by the arrow B toward the ceramic green sheet 12 where the conductive pattern 10 is not printed.

Therefore, in order to compress the ceramic green sheet 12 at the portion where the conductive pattern 10 is printed and to flow a large amount toward the ceramic green sheet 12 at the portion where the conductive pattern 10 is not printed, the ceramic green sheet 12 is formed. Studies have been made to increase the amount of the organic binder in the ceramic green sheet 12 or to add a plasticizer to the ceramic green sheet 12 to improve the flexibility and plasticity of the ceramic green sheet 12.

However, there is a limit in improving the flexibility and plasticity of the ceramic green sheet 12 by increasing the amount of the organic binder and adding a plasticizer, and the ceramic green sheet 12 is not greatly different from the conductive pattern 10. When the thickness is reduced, the flow amount of the ceramic green sheet 12 becomes insufficient, and the adhesion of the ceramic green sheet 12 on the portion where the conductive pattern 10 is not printed becomes insufficient. As shown in FIG. Delamination 14 is likely to occur, and the reliability of the laminated electronic component, such as the life characteristics, is reduced.

Also, the addition of a large amount of an organic binder or a plasticizer requires a long time for the debinding step, and furthermore, the emission of combustion gas generated by burning off the organic binder or the plasticizer to the environment has become a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly reliable laminated electronic component, which does not cause delamination even when the ceramic green sheet is thinned so as not to be so different from the conductive pattern, and a method of manufacturing the same. It is another object of the present invention to provide a ceramic powder for a multilayer electronic component used for forming a ceramic layer of such a multilayer electronic component.

[0013]

A laminated electronic component according to the present invention is a laminated electronic component comprising at least an internal electrode and a ceramic layer laminated, wherein the ceramic layer is made of ceramic formed by sintering ceramic powder. Become
The ceramic powder contains ceramic particles having pores therein. The ceramic forming the ceramic layer also contains crystal particles having pores therein.

Further, according to the method of manufacturing a laminated electronic component of the present invention, there is provided a step of forming a laminated body formed by laminating a ceramic green sheet and a conductive pattern, and pressing the laminated body in a thickness direction. A method of manufacturing a laminated electronic component, comprising: a step of firing a laminated body that has been press-bonded; It is assumed that.

Further, the ceramic powder for a laminated electronic component according to the present invention is characterized by containing ceramic particles having pores therein.

In each of the above inventions, the volume ratio of pores in the ceramic particles is preferably 5 to 10% by volume. When the volume ratio of the holes is 5 to 10% by volume, desired temperature characteristics can be obtained, the occurrence of delamination is prevented, and reliability is ensured, but when the volume ratio of the holes is less than 5% by volume. Delamination occurs and reliability cannot be secured.
If the content exceeds 0% by volume, desired temperature characteristics cannot be obtained.

In each of the above inventions, the ceramic powder for a multilayer electronic component may be, for example, BaTiO ₃ , Ca
TiO ₃ , BaZrO ₃ , PbTiO ₃ or Ba (T
i, Zr) O ₃ can be mentioned, but it is not limited to these compounds, and compounds other than these may be used.

In the examples described later, BaTiO ₃ powder having a predetermined porosity is used as the ceramic powder. However, a ceramic powder having a predetermined porosity and a ceramic powder having no porosity are mixed. May be used.

In the embodiments described later, a multilayer ceramic capacitor is described as an example. However, the present invention is not limited to a multilayer ceramic capacitor.
The present invention can be applied to all laminated electronic components having a ceramic layer and an internal conductive layer, such as a laminated piezoelectric component, a laminated inductor, a laminated filter, and a ceramic multilayer substrate.

[0020]

EXAMPLE First, BaTiO ₃ , Sr was used as a starting material.
TiO ₃ , CaZrO ₃ , MgCO ₃ , MnO, SiO
_Two were prepared. Here, as for BaTiO ₃ , one containing pores inside one particle and one not containing pores inside one particle were prepared. The one that contains voids inside
As shown in Table 1, five different kinds of pores having different volume ratios were prepared. In addition, each of the starting materials was 99% pure.
% Or more was used.

Next, Ba having different volume ratios of the inner holes is used.
For each TiO ₃ , these starting materials were weighed at a predetermined ratio, placed in a ball mill together with water, and thoroughly stirred and mixed by a wet method. Then, the obtained slurry is dried, and the obtained dried product is pulverized, and is crushed in air at 1000
Calcination was performed at ℃ to obtain ceramic powder.

Next, this ceramic powder was put into a ball mill together with an organic binder, a plasticizer and water, and sufficiently stirred and pulverized to obtain a ceramic slurry.

Next, the ceramic slurry was put into a vacuum defoamer to remove bubbles, and a thin film made of the ceramic slurry was formed by a doctor blade method. Then, the thin film made of the ceramic slurry was dried and cut to obtain a ceramic green sheet of a predetermined size. The thickness of the obtained ceramic green sheet was 4 μm.

Next, a large number of conductive patterns made of a conductive paste were printed in a matrix on one surface of the obtained ceramic green sheet. The thickness of the conductive pattern after drying was 2 μm.

Next, 60 ceramic green sheets on which the conductive pattern is printed are laminated, and ceramic green sheets for a protective layer, on which the conductive pattern is not printed, are laminated on the upper and lower sides of the ceramic green sheets to a thickness of 50 μm. At a temperature of 100 ° C., these were pressed in the thickness direction with a pressure of 100 kg / cm ₂ , and pressed to obtain a plate-shaped laminate.

Next, the plate-shaped laminate was cut into small grids for each conductive pattern to obtain a chip-shaped laminate.

Next, this chip-shaped laminate was heated at 300 ° C. for 2 hours in the air to burn off the organic binder contained therein. Then, it is baked at 1200 ° C. for 2 hours in a reducing atmosphere made of a N ₂ -1% H ₂ mixed gas, and then at 600 ° C. in an oxidizing atmosphere for 30 hours.
It was baked for a minute and reoxidized to obtain a chip-shaped laminated sintered body.

Next, the chip-shaped laminated sintered body thus obtained is cut so that the cut surface is at right angles to the internal electrodes, and the cut surface is polished. Observation was made by observation, and the presence or absence and the number of delaminations were examined. The results were as shown in Table 1.

The volume ratio of vacancies in BaTiO ₃ particles is 0
In the case of% and 3%, delamination was observed. However, the volume ratio of vacancies in the BaTiO ₃ particles is 5% to 1%.
At 1%, no delamination was observed.

Next, when the polished cut surface was observed with an electron microscope, it was found that pores were present in the ceramic crystal particles. The pores were found more in the periphery than in the upper and lower parts of the internal electrode. This is because internal stress is likely to remain above and below the internal electrode during lamination bonding, and this residual internal stress acts on the pores during sintering and is alleviated, so that there are few pores above and below the internal electrode. It is thought that it is.

Next, these chip-shaped laminated sintered bodies were
The sample was placed at a high temperature of 5 ° C., a DC 12 V was applied, the insulation resistance was measured after 1000 hours, and the reliability was evaluated. Here, the reliability was unacceptable if there was one or more insulation resistances lower than 1 MΩ. The results were as shown in Table 1.

From the results shown in Table 1, when the volume ratio of the holes in the BaTiO ₃ particles is 0% and 3%, the insulation resistance is 1%.
Some were below MΩ and did not satisfy the reliability.
However, the volume ratio of vacancies in the BaTiO ₃ particles is 5 to 1
In the case of 1%, there is no insulation resistance below 1MΩ,
It was found that the reliability was satisfied.

Next, the temperature characteristics of these chip-shaped laminated sintered bodies were examined. The results were as shown in Table 1. Temperature characteristics are as follows: Put this chip-shaped laminated sintered body in a thermostat,
The capacitance was measured and measured between 25 ° C. and 85 ° C. under the conditions of a frequency of 1 kHz and a voltage (effective value) of 1 V.

From the results shown in Table 1, when the pore volume ratio in BaTiO ₃ was 0%, 3%, 5%, and 7%, the temperature characteristics satisfied the B characteristics (JIS C 6422). But,
When the volume ratio of the holes in the BaTiO ₃ particles was 11%, the temperature characteristics did not satisfy the B characteristics.

From the above results, when the volume ratio of the vacancies in the BaTiO ₃ particles is 5% to 10%, the desired temperature characteristics are satisfied, and a highly reliable multilayer ceramic capacitor free from delamination is generated. Is obtained.

[0036]

[Table 1]

In the above embodiment, BaTiO ₃ powder having a predetermined void volume ratio was used, but BaTiO ₃ powder having a predetermined void volume ratio was used.
Similar results were obtained by using a mixture of TiO ₃ powder and BaTiO ₃ powder having no pores.

[0038]

According to the present invention, the ceramic green sheet is not much different from the conductive pattern, probably because the internal stress of the laminate is reduced by the disappearance of the pores inside the ceramic particles during the sintering of the laminate. Even if the thickness is reduced, no delamination occurs in the laminated electronic component. For this reason,
There is an effect that a highly reliable small-sized and large-capacity laminated electronic component having desired electric characteristics can be provided.

Further, according to the present invention, in the step of pressing the laminate, a rubber press or the like performed for applying a uniform pressing force to the laminate can be omitted, so that the process can be simplified. Therefore, there is an effect that the manufacturing cost of the multilayer electronic component can be reduced.

Further, since it is not necessary to add a large amount of the organic binder and the plasticizer, the time of the debinding step is shortened, and the amount of the combustion gas generated by burning and removing the organic binder and the plasticizer to the environment is reduced. There is an effect that it can be reduced.

[Brief description of the drawings]

FIG. 1A is an explanatory diagram showing a state before lamination of a ceramic green sheet and a conductive pattern in which the thickness of the ceramic green sheet is thicker than the thickness of the conductive pattern.

FIG. 1 (b) is an explanatory view showing a state after lamination of the ceramic green sheets and conductive patterns of FIG. 1 (a).

FIG. 1 (c) is an explanatory diagram showing a state when the ceramic green sheet of FIG. 1 (b) and a conductive pattern are pressed.

FIG. 2 (a) is an explanatory diagram showing a state before lamination of a ceramic green sheet and a conductive pattern, in which the thickness of the ceramic green sheet is not so different from the thickness of the conductive pattern.

FIG. 2 (b) is an explanatory view showing a state after laminating the ceramic green sheets and conductive patterns of FIG. 2 (a).

FIG. 2 (c) is an explanatory view showing a state where the ceramic green sheet of FIG. 2 (b) and a conductive pattern are pressed.

FIG. 2D is an explanatory view showing a state when the laminate of FIG. 2C is sintered.

[Explanation of symbols]

 Reference Signs List 10 conductive pattern 12 ceramic green sheet 14 delamination

Claims (10)

[Claims] 1. A laminated electronic component comprising at least an internal electrode and a ceramic layer laminated, wherein the ceramic layer is made of ceramic formed by sintering ceramic powder, and the ceramic powder has pores therein. A laminated electronic component comprising particles. 2. The method according to claim 1, wherein the volume ratio of the pores inside the ceramic particles is 5 to 10% by volume.
3. The laminated electronic component according to item 1. 3. The method according to claim 2, wherein the ceramic particles are BaTiO ₃ ,
CaTiO ₃ , BaZrO ₃ , PbTiO ₃ or Ba
(Ti, Zr) claim 1, characterized in that it consists of O ₃
Or the laminated electronic component of 2. 4. The multilayer electronic component according to claim 1, wherein the ceramic forming the ceramic layer contains crystal particles having pores therein. 5. A step of forming a laminated body formed by laminating a ceramic green sheet and a conductive pattern, a step of pressing the laminated body in a thickness direction and compressing the laminated body, and firing the laminated laminated body. And (c) using a ceramic powder containing ceramic particles having pores therein as a raw material of the ceramic green sheet. 6. The volume ratio of pores inside the ceramic particles is 5 to 10% by volume.
3. The method for producing a multilayer electronic component according to item 1. 7. The method according to claim 1, wherein the ceramic particles are BaTiO ₃ ,
CaTiO ₃ , BaZrO ₃ , PbTiO ₃ or Ba
6. The method according to claim 5, wherein said (Ti, Zr) O _{3 is formed.}
Or the laminated electronic component according to 6. 8. A ceramic powder for a laminated electronic component, comprising ceramic particles having pores therein. 9. The method according to claim 8, wherein the volume ratio of the pores in the ceramic particles is 5 to 10% by volume.
The ceramic powder according to 1. 10. The method according to claim 1, wherein the ceramic particles are BaTiO ₃ ,
CaTiO ₃ , BaZrO ₃ , PbTiO ₃ or Ba
9. The method according to claim 8, wherein the material comprises (Ti, Zr) O _3.
Or the ceramic powder for laminated electronic components according to 9.