JPH1199514A - Manufacture of ceramic slurry and manufacturing of ceramic electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent impurities from being included and realize the thorough dispersion of ceramic powder in a more perfect homogeneous form by first performing the high pressure dispersion of a ceramic liquid made up of organic solvent or water and a specific ceramic powder under a specific pressure, and adding a specified amount of a resin or a plasticizer. SOLUTION: A ceramic liquid made up of an organic solvent or water and ceramic powder with an average particle diameter of 0.01 μm or more and 3 μm or less is loaded from a casting port 1. Then this ceramic liquid is set in a highly pressurized state at 10 g/cm<2> or higher in a pressurizing part 2 with the help of a hydraulic pump or the like. The ceramic liquid is the organic solvent or the water in which the ceramic powder is dispersed. A dispersant, a suspension agent or the like is added, if necessary. Thus it is possible to deal with the highly characterizing of ceramic electronic pert, needless to say the manufacture of a green sheet, without fear that the characteristic of a finished product might deteriorate even when the green sheet and a ceramic layer after sintering are as thin as 2 μm or less.

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 ceramic electronic component such as a multilayer ceramic capacitor, a multilayer varistor, a multilayer piezoelectric element and the like used in various electronic devices. The present invention relates to a method for manufacturing a ceramic slurry and a method for manufacturing a ceramic electronic component for the purpose of improving the characteristics of various ceramic electronic components, improving the product yield, and reducing the cost by increasing the dispersion of the ceramic electronic components.

[0002]

2. Description of the Related Art In order to further reduce the size and increase the capacity of multilayer ceramic electronic components such as multilayer ceramic capacitors, it is required to reduce the thickness of the dielectric layers and ceramic layers and increase the number of layers. However, when the thickness of the dielectric layer after sintering is reduced to 2 μm or less or 1 μm or less, short-circuits occur frequently, and the reliability is rapidly reduced.

[0003] Various approaches have been taken from dielectric materials to solve such problems, but it is quite difficult.
For this reason, proposals have been made to try to bring out the ability of the material itself by devising a part for dispersing the dielectric powder and forming a green sheet. For example, JP-A-7-153
As proposed in Japanese Patent No. 646, a ball mill is used for primary mixing and dispersion, a sand mill is used for secondary mixing and dispersion, and an ultrasonic dispersion unit is used for tertiary mixing and dispersion.

[0004]

However, in such a conventional dispersing method, the properties of jigs and beads (also known as cobblestones) used in ball mills and sand mills are changed because they are mixed as impurities. Had become. Therefore, as a medium, conventionally, stabilized zirconia, alumina, rubber, glass and the like of 0.3mm to 10mmφ
Used differently, but mixed in as impurities.

[0005] Japanese Patent Application Laid-Open No. 3-47528 discloses a method of producing ceramic hollow spheres by preparing an O / W emulsion using a water-soluble metal compound. Stirring homogenizers and pressure homogenizers have been proposed.
Homogenizers can be used to disperse such water-soluble materials, however, they have never been used to disperse non-water-soluble materials such as ceramic powder.

In Japanese Patent Application Laid-Open No. 3-214704,
As a method for manufacturing a resistance temperature measuring element, it has been proposed to use a homogenizer to bond SiC whiskers. However, this proposal is intended to promote bonding by bringing the SiC whiskers in the dispersion liquid into excessive contact with each other, and to form a molded product which is hardly broken. Conventionally, there has been proposed a dispersion method using a disk which is homogenizer-dispersed and rotates at an ultra-high speed. However, when the dispersion method is used for dispersing a ceramic material, the disk material is worn out, which has been a problem as an impurity.

However, there has been no proposal of a high-pressure dispersion treatment when dispersing a slurry to more uniformly disperse the ceramic powder as proposed in the present patent. Further, even in the case of performing such high-pressure dispersion, there is a concern that members of the high-pressure dispersion machine may be mixed as impurities. When a hard material such as a ceramic slurry is dispersed, a problem arises in that equipment is worn.

[0008]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention uses a high-pressure disperser for dispersing a ceramic slurry, thereby preventing impurities such as beads, which have conventionally been a problem, from being mixed. The powder can be more uniformly dispersed in the powder, and a more stable green sheet can be produced. Further, by using the green sheet, the performance of the multilayer ceramic electronic component can be improved, and further, by optimizing the viscosity and the composition of the ceramic slurry, the high-pressure dispersion method can be put to practical use. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention
Is an organic solvent or water with an average particle size of 0.01 μm or more
A ceramic liquid consisting of a ceramic powder of 3 μm or less
Pressure 10kg / cm ^TwoAfter the high pressure dispersion as described above, a predetermined amount of resin
Alternatively, add a plasticizer to produce a ceramic slurry.
Is a method of producing ceramic slurry, which is dispersed under high pressure.
As a result, a ceramic slurry with a uniform particle size and
Has the effect of being

[0010] The invention according to claim 2 of the present invention provides an organic solvent
Agent or water and average particle size of 0.01μm or more and 3μm or less
10kg of ceramic liquid consisting of ceramic powder
/cm ^TwoAfter high pressure dispersion as described above, a predetermined amount of resin or
Add a plasticizer and apply a viscosity of 1 poise to 100 poise.
Create a lamic slurry and place it on a given substrate
Apply and dry to a thickness of at least 10 μm
A ceramic green sheet is formed and the ceramic green sheet is formed.
Laminate, cut and fire lean sheet with base metal internal electrode
After the production of ceramic electronic components to form external electrodes
This is a method of dispersing the composition by high pressure dispersion.
That high-performance ceramic electronic components can be manufactured.
It has a function.

According to a third aspect of the present invention, a ceramic green sheet is formed by applying and drying using a die coater or a gravure coater or using an ink jet apparatus. The method for manufacturing a ceramic electronic component according to the above, wherein a ceramic slurry that can be more uniformly dispersed by using high-pressure dispersion is obtained, so that even when a ceramic green sheet is formed using a die coater or a gravure coater, a more uniform green A sheet is obtained, which has an effect that a ceramic electronic component with high characteristics can be manufactured.

[0012] The invention according to claim 4 of the present invention is characterized in that the ceramic liquid is formed from a resin or a dispersant, an organic solvent or water, and a ceramic powder having an average particle diameter of 0.01 µm or more and 3 µm or less. A method for manufacturing a ceramic electronic component according to claim 2, which has an effect that various ceramic electronic components can be manufactured at low cost by using a multilayer ceramic green sheet.

According to a fifth aspect of the present invention, when the ceramic liquid is dispersed under high pressure, a pressure of 1 is applied from a plurality of coating portions.
^{3. The} method for producing a ceramic electronic component according to claim 2, wherein the liquids collide with each other at 0 kg / cm ² or more, and the liquids collide with each other, whereby mixing of impurities can be minimized. It has the effect that various ceramic electronic components with high characteristics can be manufactured.

According to a sixth aspect of the present invention, when the ceramic liquid is dispersed under high pressure, a pressure of 10 kg / min.
^{3. The} method of claim 2, wherein the particles are dispersed by colliding with a diamond, ceramic, or cemented metal surface with a diameter of ² cm or more.
A method for manufacturing a ceramic electronic component as described above, which has an effect of minimizing mixing of impurities by causing liquids to collide with each other and manufacturing various ceramic electronic components with high characteristics.

According to a seventh aspect of the present invention, a ceramic liquid is filtered with a filter having an opening diameter of 100 μm or less, and then dispersed under high pressure at a pressure of 10 kg / cm ² or more. 3. The method for producing a ceramic electronic component according to claim 2, wherein a ceramic slurry is formed by adding a predetermined amount of a resin or a plasticizer after filtration. This has the effect of minimizing the production of various ceramic electronic components with high characteristics.

According to an eighth aspect of the present invention, the ceramic liquid has a solid content of 30% by weight to 80% by weight, a viscosity of 0.01 to 50 poises, and an opening diameter of 10 to 50 poises.
After filtration through a filter medium of not more than 00 μm and not less than 10 μm,
^{3. The} method for producing a ceramic electronic component according to claim 2, wherein the dispersion is performed a predetermined number of times at a pressure of 10 kg / cm ² or more using a high-pressure disperser, and the dispersion is performed with a filter medium having an opening diameter of 50 μm or less. By doing so, the mixing of impurities during dispersion can be minimized, and various ceramic electronic components with high characteristics can be manufactured.

According to a ninth aspect of the present invention, the ceramic liquid is dispersed at a pressure of 10 kg / cm ² or more using a high-pressure dispersing machine having a plurality of high-pressure dispersing parts before and after the high-pressure dispersing device. 3. The method for manufacturing a ceramic electronic component according to claim 2, wherein the pressure of the rear high-pressure application section is set to half or less of the pressure of the application section, and the back pressure is reduced to reduce the kind of back pressure to the front high pressure. It can be applied to the application section, thus making it possible to make the dispersion uniform and extend the life of the equipment itself, and has the effect that various ceramic electronic components with high characteristics can be manufactured at low cost.

According to a tenth aspect of the present invention, a ceramic liquid comprising an organic solvent or water and a ceramic powder having an average particle size of 0.01 μm or more and 3 μm or less is subjected to a pressure of 10 μm.
After high-pressure dispersion at a pressure of at least kg / cm ² , a predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 20 poise. After coating in a reverse pattern or stripe pattern by gravure printing or ink jet printing so as to have the following thickness and drying to form a ceramic green sheet, laminating the ceramic green sheet together with the base metal internal electrode, cutting and firing A method of manufacturing a ceramic electronic component forming an external electrode, in order to absorb the thickness of the internal electrode of the multilayer ceramic electronic component, by forming a reverse pattern or a stripe pattern by gravure printing or ink jet printing,
This has the effect that ceramic electronic components can be manufactured with a high yield.

According to the invention of claim 11 of the present invention, a ceramic liquid comprising an organic solvent or water and a ceramic powder having an average particle diameter of 0.01 μm or more and 3 μm or less is pressurized at a pressure of 10 μm.
After dispersing under a high pressure of at least kg / cm ² , a predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 10 poise, and this is used as a base metal internal electrode formed on a base film. Is coated in a reverse pattern or stripe pattern by gravure printing or ink jet printing to a thickness of 1 μm or more and 10 μm or less so as to cover the entire surface, dried to form a ceramic green sheet, and the ceramic green sheet is laminated and cut. This is a method for manufacturing a ceramic electronic component in which external electrodes are formed after firing, and a more uniform ceramic raw sheet with embedded electrodes can be produced, so that various ceramic electronic components can be manufactured with a high yield. Having.

According to a twelfth aspect of the present invention, a ceramic liquid comprising an organic solvent or water and a ceramic powder having an average particle size of 0.01 μm or more and 3 μm or less is compressed to a pressure of 10 μm.
After dispersing under a high pressure of at least kg / cm ² , a predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 10 poise, and this is used as a base metal internal electrode formed on a base film. Is coated in a reverse pattern or stripe pattern by gravure printing or ink jet printing to a thickness of 1 μm or more and 10 μm or less so as to fill the gap, and dried to form a ceramic green sheet, and the ceramic green sheet is laminated and cut. This is a method for manufacturing a ceramic electronic component in which an external electrode is formed after firing. Since the occurrence of irregularities on the base metal internal electrode can be prevented, various ceramic electronic components can be manufactured with a high yield.

According to a thirteenth aspect of the present invention, a ceramic liquid comprising an organic solvent or water and a ceramic powder having an average particle diameter of 0.01 μm or more and 3 μm or less is pressurized at a pressure of 10 μm.
After dispersing under a high pressure of at least kg / cm ² , a predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 10 poise, and the slurry is formed into a plurality of layers formed on a base film. The base metal internal electrode and the ceramic green sheet are multilayered, and the base metal
A method for manufacturing ceramic electronic components in which ceramic green sheets are formed by coating and drying to a thickness of not more than μm or less, and after laminating, cutting and firing the ceramic green sheets, external electrodes are formed. Using a green sheet has the effect that various ceramic electronic components can be manufactured at low cost.

(Embodiment 1) FIG. 1 shows a high-pressure disperser. In FIG. 1, reference numeral 1 denotes an inlet from which a ceramic liquid or ceramic slurry is injected. Reference numeral 2 denotes a pressure unit, which pumps the applied ceramic liquid or ceramic slurry to 10 kg / cm ² or more (usually 500 kg) using a hydraulic pump or the like.
/ Cm ² or 1700 kg / cm ² , which can be adapted to the intended use).

Here, the ceramic liquid is obtained by dispersing a ceramic powder in an organic solvent or water, and a dispersant, a suspending agent and the like can be added as necessary. The ceramic slurry forms a ceramic green sheet by coating and drying. That is, the ceramic liquid corresponds to a work in process of the ceramic slurry. Reference numeral 3 denotes a mixing and dispersing unit, in which a high-pressure ceramic liquid or ceramic slurry is sprayed on a special jig, or a plurality of capillaries eject a high-pressure ceramic liquid or ceramic slurry against each other. Is the place to do the dispersion.

In the pressure section, the pressure of the ceramic liquid or ceramic slurry is raised to a high pressure of at least 100 kg / cm ² or more. The pressure during this dispersion can be monitored by attaching a pressure gauge to the pressure section 2 (or between the pressure section 2 and the mixing / dispersion section 3). The inside of the mixing and dispersing section 3 can be protected from abrasion by locally forming it from diamond, ceramic, or superhard metal. In this way, a ceramic liquid or a ceramic slurry to which a high pressure of 100 kg / cm ² or more is applied is introduced into the mixing and dispersing portion, and the liquids collide with each other (or the liquid to a predetermined jig) at a speed exceeding the speed of sound and are dispersed. . The high pressure dispersed ceramic liquid or ceramic slurry is discharged from the coating outlet 4.

As such an apparatus, a pressure-type homogenizer manufactured by Gorin, USA, or the like can be used. By using such an apparatus, a ceramic liquid or ceramic slurry can be applied to 100 kg / cm ² or more (3000 k depending on the equipment specifications).
g / cm ² ). In order to extend the life of the disperser and stabilize the dispersion while avoiding contamination of the ceramic liquid or ceramic slurry with impurities, the material of the mixing and dispersing part should be made of diamond, ceramic or cemented carbide. It is desirable to use.

As the ceramic powder, a powder mainly composed of barium titanate having a particle size of 2 μm was selected and mixed with a binder resin in a solvent to obtain a ceramic slurry. Next, this ceramic slurry was dispersed under high pressure. The pressure at the time of dispersion can be measured by directly attaching a pressure gauge to the mixing / dispersing section 3.

For this dispersion, a high-pressure disperser as shown in FIG. 1 was used. In FIG. 1, reference numeral 1 denotes a charging port through which a ceramic slurry which has been preliminarily kneaded is supplied. Reference numeral 2 denotes a pressure unit which can bring the supplied ceramic slurry into a high pressure state of 100 kg / cm ² or more by a hydraulic pump or the like. Reference numeral 3 denotes a mixing and dispersing unit, in which the ceramic slurry in a high pressure state is sprayed on a special jig or the ceramic slurries ejected at a high pressure from a plurality of capillaries collide with each other to perform dispersion. Location.

In the pressure section, the ceramic slurry is raised to a high pressure of at least 100 kg / cm ² or more. The pressure at the time of this dispersion is the pressure part 2 (or the pressure part 2).
And a mixing / dispersing section 3), a pressure gauge can be attached to monitor. The inside of the mixing and dispersing section 3 can be protected from abrasion by locally forming it from diamond, ceramic, or superhard metal. In this manner, the ceramic slurry to which a high pressure of 100 kg / cm ² or more is applied is introduced into the mixing and dispersing portion, and the liquids collide with each other (or the liquids collide with a predetermined jig) at a speed exceeding the speed of sound. The ceramic slurry thus dispersed under high pressure is discharged from the discharge port 4.

As such an apparatus, a pressure-type homogenizer manufactured by Gorin, USA, or the like can be used. By using such a device, 100 kg /
cm (depending on the device specification 3000 kg / cm ² or higher) ^more by dispersing while applying a high pressure, easily increase the density of the current collector coating film 0.35 g / cc or more (particularly 0.50 or higher) Let me do. In order to extend the life of the disperser and stabilize the dispersion while avoiding contamination of the ceramic slurry with impurities, the material of the mixing and dispersing part should be made of diamond, ceramic, or cemented carbide. desirable. Some of such dispersers are called microfluidizers, nanomizers, and the like.

For comparison, a conventional ceramic slurry dispersion method was conducted using a rotary homogenizer, an ultrasonic homogenizer, and various other mixers, ball mills, and sand mills. Is 4 μm or more, high characteristics are obtained, but 3 μm
m or less, especially around 2 μm, the characteristics dropped sharply. On the other hand, in the case of high-pressure dispersion, even if the thickness of the sintered ceramic layer was 2 μm or less, the same high characteristics and high reliability as those of 4 μm or more were obtained.

Then, when these samples were analyzed,
In spite of the fact that the ceramic powder as the starting material was the same, the one prepared by the conventional dispersing method had voids (micro defects and micro holes, which are likely to cause defects) of about 0.1 μm to 1 μm. Many voids were generated, but almost no such voids were generated in the sample subjected to high-pressure dispersion. From this, it was found that the packing (densification, high density) of the ceramic particles was improved by the high pressure dispersion. In addition, the composition analysis of the ceramic layer was also performed.Contamination of impurity elements that could deteriorate the reliability and the temperature characteristics of capacitance was considerably confirmed in the conventional product. Almost never.

In the case of a high-pressure disperser, the ceramic slurry is dispersed by hitting the liquids under high pressure (without touching air) or by striking against a backing plate.
There is also an advantage that bubbles are hardly generated even when the ceramic slurry is dispersed with various dispersants added thereto.

The pressure of the high-pressure disperser is 10 kg / cm ²
The above (especially 200 kg / cm ² or more) is desirable. 5 kg / cm ²
In the following, the pressure is insufficient and the dispersing effect is often insufficient. The dispersion pressure is desirably 250 kg / cm ² or more and 500 kg / cm ² or less. When such high-pressure dispersion is performed, the ceramic slurry self-heats from about 50 ° C. to about 80 ° C., which may cause lot fluctuation of the ceramic slurry. Therefore, it is desirable to add a water cooling mechanism for minimizing heat generation of the ceramic slurry. 1000kg / cm ²
An ultra-high pressure disperser capable of the above dispersion, 3000 kg / cm ²
Ultra-high pressure dispersers of the order can also be used. Also, the number of times of dispersion need not be limited to one. By repeatedly processing a predetermined ceramic slurry a plurality of times with the same disperser, the quality of the ceramic slurry can be stabilized. Further, even when the dispersion pressure pulsates (the pressure fluctuates up and down regularly), the degree of dispersion can be stabilized by repeating the dispersion a plurality of times.

(Embodiment 2) In Embodiment 2, FIG.
The structure of the mixing / dispersing unit 3 will be described in detail with reference to FIG. FIG. 2 shows the inside of the mixing / dispersing unit of FIG. 5a and 5b for ceramic liquid and ceramic slurry
Flows at high speed along the directions indicated by arrows from the plurality of input portions indicated by. Then, they merge with each other in the collecting section 6a, where they are mixed, dispersed and homogenized violently.

As described above, by mixing the liquids,
The ceramic liquid or the ceramic slurry can be highly dispersed while the pulverization of the ceramic powder is prevented, and the contamination of impurities can be suppressed.

For comparison, a ceramic green sheet was prepared by using a ceramic slurry prepared by a conventional ball mill method and a ceramic slurry prepared in the second embodiment. It was also found that the surface roughness was small, and the latter was highly dispersed. Further, a multilayer ceramic capacitor was prepared using the thus prepared ceramic green sheets.
Despite the use of ceramic powder having the same X7R characteristics, the former did not become a commercial product because the temperature characteristics deviated from X7R. On the other hand, the latter had a temperature characteristic satisfying X7R, and could be commercialized.

The average particle size of the ceramic powder is 0.1.
It is desirable that the thickness be from 01 μm to 3 μm. Ceramic particles having a particle size of 0.005 μm or less have too large a specific surface area and are difficult to be slurried. When ceramic powder having a size of 4 to 5 μm or more is used, a laminated ceramic component having a fired ceramic layer thickness of 4 μm or less (because only one particle is contained) cannot be formed in principle. By setting the viscosity of the ceramic slurry to 1 poise or more and 100 poise or less, the slurry can be applied by a die coater or a gravure coater.
If the solid content of the ceramic slurry is reduced even at 0.5 poise or less, the coating itself can be performed, but the reliability of the finished product may be poor. The coating itself is possible even with a viscosity of 200 poise or more, but the surface of the finished ceramic green sheet becomes rough, and there is a limit to the ultra-thin ceramic layer.

Such a high-pressure dispersion is suitable for the production of a ceramic green sheet which is coated on a resin film of polyester or the like in an ultrathin layer of 1 μm to 10 μm.
Further, since the amount of impurities mixed into the ceramic slurry is small, it can be used for manufacturing a multilayer ceramic electronic component using a base metal internal electrode, which is liable to be a problem of mixing.
The present invention can be used for manufacturing multilayer ceramic electronic components having a small capacity change rate with respect to temperature, such as B characteristics, X7R characteristics, and further C characteristics.

(Embodiment 3) In Embodiment 3, FIG.
The structure of the mixing / dispersing unit will be described in detail with reference to FIG.
FIG. 3 shows the inside of the mixing / dispersing unit of FIG. The ceramic liquid or the ceramic slurry flows at a high speed from the input portion indicated by 5c in the direction indicated by the arrow. Then, it is caused to violently collide with the collision surface indicated by 7, where it is mixed, dispersed and homogenized.

As described above, by colliding the liquid with the collision surface 7 at a high pressure and at a high speed, the average particle size of the ceramic powder can be reduced (that is, miniaturized), and at the same time, contamination of impurities can be suppressed.

For comparison, alumina beads and zirconia beads were used in a conventional bead mill, and the same ceramic powder (average particle size: 1.5 μm) was used.
The pulverization of the ceramic powder was performed until the thickness became 7 μm. As an example of the invention, the ceramic powder was ground in the same manner as in the third embodiment. The average particle size of the ceramic powder thus completed was measured.
It was crushed to μm. However, in the case of the conventional product, when elemental analysis was performed, a large amount of alumina element was detected in the case of using alumina beads. Also, a small amount of zirconia element was detected in the sample using zirconia beads. On the other hand, in the case of the present embodiment, such an element was not detected. In particular, since diamond is used for the collision surface 7 used in the third embodiment, even if diamond is detected as an impurity, it is expected that the diamond is volatilized during firing because the element is carbon. It does not matter when manufacturing the part.

When dispersing the ceramic liquid, high-pressure dispersion can be performed in a state where a plasticizer or a dispersant is added in advance. The solvent at this time is an organic solvent, a water-soluble organic solvent,
Water, alcohol, or a mixed solvent thereof may be used. Also, in the ceramic liquid, 0.1
By adding about 3% by weight of the resin, the dispersion of the ceramic powder can be stabilized (without increasing the viscosity of the ceramic liquid). Such resins include butyral resin, cellulose resin, and acrylic resin.

(Embodiment 4) In Embodiments 1 to 3,
The effect on the ceramic powder and the ceramic green sheet has been described. In the fourth embodiment, the ceramic slurry prepared in this manner is used to prevent the unevenness of the internal electrode, which is a problem at the time of high lamination of the multilayer ceramic capacitor. . First, Patent No. 2 previously proposed by the inventors
According to JP-A-636306, an electrode-embedded GS was prepared (note that nickel, which is a base metal electrode, was used for the electrode). At this time, a high-pressure disperser was used to disperse the ceramic slurry used for embedding the electrodes. By using a high-pressure disperser, it was possible to easily flatten the ceramic green sheet with embedded electrodes.

Then, using this ceramic green sheet with embedded electrodes, 600 layers were laminated, and a product could be manufactured without any problem. Also, up to 1000 layers were stacked as a stacking experiment, but no particular problem occurred. On the other hand, in the one made with the conventional ball mill,
Despite having the same composition of the ceramic slurry (resin amount, ceramic amount, etc.), planarization is insufficient.
When the 00 layers were laminated, the irregularities due to the thickness of the internal electrodes became too large, and the ceramic green sheets were broken during lamination, and the lamination could not be performed.

Then, when the viscosity of these ceramic slurries was measured, it was found that the viscosity of the ceramic slurry was less than half that of the conventional product when subjected to high pressure dispersion. As a reminder, the solids of both ceramic slurries were measured and were the same. From the above, it was found that the fluidity of the ceramic slurry was improved by the high-pressure dispersion, and the leveling (flattening) at the time of embedding the electrode was improved.

It is desirable that the solid content of the ceramic liquid or ceramic slurry is 30% by weight or more and 80% by weight or less and the viscosity is 0.01 poise to 50 poises in a state of high pressure dispersion (according to experiments by the inventors). In the case of a 50 poise ceramic slurry mainly composed of polyvinyl butyral resin, barium titanate and butyl acetate,
By performing high-pressure dispersion at 100 kg / cm ^2, the viscosity could be reduced to 10 poise or less.)

In the case of high-pressure dispersion, agglomerates in the liquid may cause clogging of the apparatus due to passage through the narrow gaps shown in FIGS. In order to prevent this, it is desirable to perform high-pressure dispersion after filtering with a filter medium having an opening diameter of 1000 μm or less and 10 μm. The inventors used a stainless steel sieve, but when the opening diameter of the sieve was 1500 μm, the device was packed, and the work was stopped for half a day for repair and cleaning. When the opening diameter of the sieve was 5 μm, both the ceramic liquid and the ceramic slurry were packed in the sieve and could not be filtered (aggregates of several μm were observed later when measured by a particle size distribution system).

After the completion of the high-pressure dispersion, it is desirable to filter the ceramic liquid or ceramic slurry with a filter having an opening diameter of 50 μm or less. By doing so, it is possible to remove lint and dust mixed from the atmosphere in the work place.

(Embodiment 5) In Embodiment 5, in order to flatten an internal electrode formed on a base material, when a reverse pattern is formed using a ceramic slurry, the ceramic slurry dispersed under high pressure is used. Using. In FIG.
Reference numeral 8 denotes an internal electrode, which is formed on a support 9. FIG.
4A is a perspective view, and FIG. 4B is a sectional view. In FIG. 5, reference numeral 10 denotes a ceramic reverse pattern, which is formed on the support 9. FIG. 6 shows a state in which the internal electrode 8 and the ceramic reverse pattern 10 are formed on the support 9 so as to be smooth on the same plane without overlapping each other. As shown in FIG. 6, the internal electrode 8 of FIG. 4 and the ceramic reverse pattern 10 of FIG. 5 have a front-to-back (or negative-positive) relationship.
In order to prevent the internal electrode 8 and the ceramic reverse pattern 10 from actually overlapping, it is desirable to design a gap of about 50 μm.

This will be described in more detail. The high-pressure dispersed ceramic slurry proposed in the present invention has high fluidity (it can be highly dispersed even if the viscosity is as low as about 0.01 poise if a resin is selected). Ceramic reverse pattern 10
It can print continuously for a long time. After flattening the electrode 8 with the ceramic reverse pattern 10 in this way, the inventors stack the layers as shown in Japanese Patent Application Laid-Open No. 64-65831, fire, and form external electrodes to obtain the fired dielectric. Various multilayer ceramic capacitors having a layer thickness of 1 to 2 μm and a number of laminations of 500 to 1000 were produced with high yield.

On the other hand, various types of multilayer ceramic capacitors having a ceramic layer thickness of 1 to 2 μm after firing were similarly prepared by using conventional ball mills, rotary homogenizers, bead mills and the like. Some of the characteristics were out of the standard.

In particular, in the case of the product prepared by the present dispersion method, a narrow gap is passed at a high pressure and at a high speed, so that an aggregate of 10 μm to 50 μm or more hardly remains in the ceramic liquid or ceramic slurry. Therefore, even when gravure printing is performed for a long time, the doctor blade and the gravure plate are not damaged. In addition, even when non-contact printing is performed by ink jet printing, the coating outlet (diameter: 10 μm to 100 μm) of the ink jet is not filled.

By setting the viscosity to 0.01 poise or more and 10 poise or less, a slurry used for both ink jet printing and gravure printing can be prepared. The viscosity is 0.
If it is less than 005 poise, printing cannot be performed even with an ink jet. In addition, if it becomes 10 poise or more, even if gravure printing can be performed, the surface of the printed coating film will be rough,
Leveling worsens.

(Embodiment 6) In Embodiment 6, a method of forming a ceramic stripe pattern instead of the ceramic reverse pattern 10 will be described. FIG.
5A, a ceramic stripe pattern 11 is formed on a support 9 so as to fill a gap between the internal electrodes 8. Further, in FIG.
And the ceramic raw sheet 12 is formed so as to fill both the ceramic stripe patterns 11. As described above, by forming the ceramic stripe pattern 11, by forming a pattern between the internal electrodes as proposed by the present inventors in Japanese Patent No. 2658223, the ceramic raw sheet with embedded electrodes can be further laminated. In addition to being able to do so, we succeeded in making the thickness of the ceramic layer ultra-thin to the order of 1 μm.

In particular, the inventors proposed such a ceramic sheet with embedded electrodes at the time of 1988. After that, experiments were conducted on several hundred types of ceramic slurry compositions, various binder resins, additives and dispersants. I've been repeating. However, even if the ceramic slurry is optimized, when the dispersion is performed, the mixing of impurities from the disperser has become a problem. Initially, products were developed by taking into account such contaminants, but could not cope with ultra-thin ceramic layers of less than 2 μm. By introducing such a high-pressure dispersion method, the inventors were able to prevent, for the first time, mixing of impurities such as metals, metal oxides, and ceramics.

(Embodiment 7) In Embodiment 7, a method for manufacturing a ceramic electronic component for solving the problem of side cracks, which are likely to occur when multilayer ceramic capacitors are super-laminated, will be described. FIG. 8 is a partial cross-sectional perspective view of a multilayer ceramic capacitor in which side cracks have occurred.
In FIG. 8, 13 is a ceramic layer and 14 is an internal electrode, which is formed of a base metal such as nickel or copper, or an alloy thereof. Reference numeral 15 denotes an external electrode. Reference numeral 16 denotes a side crack, which is likely to occur when the number of stacked internal electrodes 14 exceeds 200 to 400 or when the thickness of the ceramic layer sandwiched between the plurality of internal electrodes 14 is reduced to 1 to 2 μm.

By selecting the high-pressure dispersion method of the ceramic liquid or ceramic slurry proposed in the present invention, the homogenization and pulverization and the homogenization of the ceramic powder can be performed, so that the side surface crack is hardly generated from the ceramic material side. Also, by introducing a ceramic reverse pattern or a ceramic stripe pattern as proposed in the fifth and sixth embodiments, side cracks can be physically prevented.

In the high-pressure dispersing machine shown in FIG. 1, a plurality of mixing / dispersing sections 3 may be provided. By doing so, a pulsating flow at the time of coating the liquid from the coating outlet 4 can be prevented, and uniform dispersion at a uniform pressure can be performed. At this time, by setting the set pressure of the pressure application portion on the rear side (closer to the coating outlet 4) lower than the pressure application portion on the front side (closer to the inlet 1), a kind of back pressure can be obtained. Is applied to the front pressure application portion, and the life of the equipment can be extended.

[0059]

As described above, according to the present invention, even when the thickness of the green sheet and the ceramic layer after sintering is reduced to 2 μm or less, the characteristics of the product are not deteriorated. In addition, it can respond to the improvement of characteristics of ceramic electronic components.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a high-pressure disperser according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a dispersed portion according to a second embodiment of the present invention.

FIG. 3 is a conceptual diagram of a dispersion part according to a third embodiment of the present invention.

FIG. 4 (a) is a perspective view illustrating an internal electrode formed on a support according to a fifth embodiment of the present invention.

FIG. 5A is a perspective view illustrating a ceramic reverse pattern formed on a support according to the embodiment; FIG.

FIG. 6A is a perspective view illustrating a state in which an internal electrode and a ceramic reverse pattern are formed on a support according to the embodiment; FIG.

FIG. 7 is a perspective view illustrating a state in which internal electrodes and ceramic stripes are formed on a support according to a sixth embodiment of the present invention.

FIG. 8 is a partial cross-sectional perspective view of a multilayer ceramic capacitor having side cracks.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input port 2 Pressure part 3 Mixing / dispersing part 4 Coating outlet 5a, 5b, 5c Input part 6a, 6b, 6c Recovery part 7 Collision surface 8 Internal electrode 9 Support body 10 Ceramic reverse pattern 11 Ceramic stripe pattern 12 Ceramic raw sheet 13 Ceramic Layer 14 Internal electrode 15 External electrode 16 Side crack

Claims (13)

[Claims] An organic solvent or water having an average particle size of 0.0
A method for producing a ceramic slurry, comprising dispersing a ceramic liquid comprising ceramic powder having a size of 1 μm or more and 3 μm or less at a pressure of 10 kg / cm ² or more under high pressure, and then adding a predetermined amount of a resin or a plasticizer to produce a ceramic slurry. 2. An organic solvent or water having an average particle size of 0.0
After a high-pressure dispersion of a ceramic liquid comprising a ceramic powder of 1 μm or more and 3 μm or less at a pressure of 10 kg / cm ² or more, a predetermined amount of resin or plasticizer is added to prepare a ceramic slurry having a viscosity of 1 to 100 poise. It is coated on a predetermined substrate to a thickness of 1 μm or more and 10 μm or less, dried to form a ceramic green sheet, and the ceramic green sheet is laminated, cut, and fired with a base metal internal electrode, and then the external electrode is formed. A method for manufacturing a ceramic electronic component for forming the same. 3. The method for producing a ceramic electronic component according to claim 2, wherein the ceramic green sheet is formed by applying and drying using a die coater or a gravure coater or using an ink jet device. 4. The method according to claim 1, wherein the ceramic liquid is a resin or a dispersant.
Organic solvent or water and average particle size of 0.01μm or more and 3μ
3. The method for manufacturing a ceramic electronic component according to claim 2, wherein the ceramic electronic component is formed from a ceramic powder of m or less. 5. The ceramic electronic component according to claim 2, wherein, when the ceramic liquid is dispersed under high pressure, the liquids collide with each other at a pressure of 10 kg / cm ² or more from a plurality of coating portions and dispersed. Production method. 6. The method according to claim ² , wherein when the ceramic liquid is dispersed at a high pressure, the liquid is colliding with a diamond, ceramic, or cemented metal surface at a pressure of 10 kg / cm ² or more from the coating portion to be dispersed. Manufacturing method of ceramic electronic components. 7. A ceramic liquid is filtered through a filter having an opening diameter of 100 μm or less, and then dispersed under high pressure at a pressure of 10 kg / cm ² or more, and filtered through a filter having an opening diameter of 10 μm or less. 3. The method for manufacturing a ceramic electronic component according to claim 2, wherein a ceramic slurry is formed by adding an agent. 8. The ceramic liquid is filtered through a filter medium having a solid content of 30% by weight to 80% by weight, a viscosity of 0.01 poise to 50 poises and an opening diameter of 1000 μm to 10 μm, and then a high-pressure dispersing machine. 10kg / using
^{3. The} method for producing a ceramic electronic component according to claim 2, wherein the particles are dispersed a predetermined number of times in a range of not less than ² cm ² and filtered through a filter having an opening diameter of 50 μm or less. 9. The pressure of the ceramic liquid is 10 kg / cm using a high-pressure dispersing machine having a plurality of high-pressure dispersing parts before and after.
^3. The pressure is dispersed at ² or more, and the pressure of the rear high pressure application unit is set to be less than half the pressure of the front high pressure application unit.
The manufacturing method of the ceramic electronic component described in the above. 10. An organic solvent or water having an average particle size of 0.1.
After high-pressure dispersion of a ceramic liquid comprising a ceramic powder of not less than 01 μm and not more than 3 μm at a pressure of 10 kg / cm ² or more,
A predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 20 poise, which is gravure-printed or ink-jet printed on a predetermined base material to a thickness of 1 μm to 10 μm. Coating and drying in reverse pattern or stripe pattern by printing to form a ceramic green sheet, laminating the ceramic green sheet together with the base metal internal electrode, cutting and firing, then manufacturing the ceramic electronic component to form the external electrode Method. 11. An organic solvent or water having an average particle size of 0.1.
After high-pressure dispersion of a ceramic liquid comprising a ceramic powder of not less than 01 μm and not more than 3 μm at a pressure of 10 kg / cm ² or more,
A ceramic slurry having a viscosity of 0.01 poise or more and 10 poise or less is prepared by adding a predetermined amount of resin or plasticizer, and the slurry is 1 μm or more and 10 μm or less so as to entirely cover the base metal internal electrode formed on the base film. A ceramic green sheet is formed by applying a reverse pattern or a stripe pattern by gravure printing or ink jet printing to a thickness of, forming a ceramic green sheet, and laminating, cutting and firing the ceramic green sheet, and then forming a ceramic to form an external electrode. Manufacturing method of electronic components. 12. An organic solvent or water having an average particle size of 0.1.
After high-pressure dispersion of a ceramic liquid comprising a ceramic powder of not less than 01 μm and not more than 3 μm at a pressure of 10 kg / cm ² or more,
A ceramic slurry having a viscosity of 0.01 poise to 10 poise is prepared by adding a predetermined amount of resin or plasticizer, and the slurry is 1 μm or more and 10 μm or less so as to fill gaps between base metal internal electrodes formed on the base film. A ceramic green sheet is formed by applying a reverse pattern or a stripe pattern by gravure printing or ink jet printing to a thickness of, forming a ceramic green sheet, and laminating, cutting and firing the ceramic green sheet, and then forming a ceramic to form an external electrode. Manufacturing method of electronic components. 13. An organic solvent or water having an average particle size of 0.1.
After high-pressure dispersion of a ceramic liquid comprising a ceramic powder of not less than 01 μm and not more than 3 μm at a pressure of 10 kg / cm ² or more,
A predetermined amount of a resin or a plasticizer is added to prepare a ceramic slurry having a viscosity of 0.01 poise to 10 poise, and a plurality of base metal internal electrodes and a ceramic green sheet formed on a base film are multilayered. After coating the base metal internal electrode or the ceramic green sheet to a thickness of 1 μm or more and 10 μm or less and drying to form a ceramic green sheet, and laminating, cutting and firing the ceramic green sheet, A method for manufacturing a ceramic electronic component for forming an electrode.