JP2002284580A - Method for manufacturing ceramic green sheet and ceramic electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic green sheet without building up a crack and capable of making a thick layer in case that a aqueous solvent is used. SOLUTION: In the method for manufacturing the ceramic green sheet that forms the ceramic sheet on a substrate by using a dielectric paint, the method for manufacturing the ceramic green sheet is characterized in that the substrate at least satisfies any property selected from the group consisting of permeability of larger than 0 g/cm<2> s and smaller than 2 g/cm<2> s, a gas cavity diameter of longer than 0.5 μm and shorter than 11 μm and a gas cavity amount of more than 0.05 cc/g and less than 0.63 cc/g.

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 green sheet and a method for manufacturing a ceramic electronic component, which can increase the thickness of a sheet without causing cracks even when an aqueous solvent is used.

[0002]

2. Description of the Related Art In order to manufacture ceramic electronic components such as a CR-embedded substrate and a multilayer ceramic capacitor, usually,
First, a dielectric paint composed of a ceramic powder, a binder (such as an acrylic resin or a butyral resin), a plasticizer, and an organic solvent (such as methylene chloride) is prepared. Next, this dielectric paint is PET-coated using a doctor blade method or the like.
After coating on a film and drying by heating, the PET film is peeled off to obtain a ceramic green sheet. next,
The internal electrodes are printed on this ceramic green sheet and dried, and the laminated body is cut into chips to obtain green chips, and after firing these green chips,
Form external electrodes and manufacture electronic components such as multilayer ceramic capacitors.

When manufacturing a multilayer ceramic capacitor, the interlayer thickness of a sheet on which internal electrodes are formed is in a range of about 2 μm to 50 μm based on a desired capacitance required as a capacitor. In the multilayer ceramic capacitor, a portion where no internal electrode is formed is formed in an outer portion of the capacitor chip in the stacking direction.

The thickness of the dielectric layer corresponding to the portion where the internal electrode is not formed is about several hundred μm, and this portion is formed using a relatively thick ceramic green sheet on which no internal electrode is printed. . Since the thickness of the green sheet on which the internal electrodes are printed is relatively thin, if the outer portion is formed using this thin green sheet, the number of layers increases, the number of manufacturing steps increases, and the manufacturing cost decreases. Leads to an increase. In the case of a ceramic paint containing an organic solvent, the molded thickness of the sheet can be relatively freely changed according to the purpose of the site to be used, and a relatively thick sheet can be molded.

[0005]

On the other hand, in recent years, in the production of ceramic electronic parts, not only the cost of organic solvents but also the emission of organic solvents to the atmosphere by drying and exhaustion, that is, problems of air pollution and warming. Or, the problem of the cost of the solvent recovery device has been pointed out. For this reason, there is an increasing demand for a water-soluble binder that does not use an organic solvent, as a binder for a ceramic green sheet paint. Among the water-soluble binders, polyvinyl alcohol is widely used because it has excellent coating properties, high film strength, and excellent handling properties as compared with other water-soluble binders.

[0006] However, polyvinyl alcohol is
Since it is insoluble in solvents other than water, the main solvent in the paint is only water. Since water has a higher boiling point than an organic solvent, it is necessary to raise the drying temperature of the green sheet.
As a result, cracks are likely to occur during the formation of the ceramic green sheet.

Therefore, it has been extremely difficult to form a relatively thick green sheet (for example, 100 μm to several hundred μm) of a green sheet, which is possible with an organic solvent-based paint, using a water-based paint.

[0008] In addition, if the drying temperature is not gradually increased and time is required, the sheet cannot be formed, so that there is a problem that the drying time of the sheet forming is increased (the drying speed cannot be increased).

An object of the present invention is to increase the thickness of a sheet (for example, to 1) without generating cracks even when an aqueous solvent is used.
It is an object of the present invention to provide a method for producing a ceramic green sheet, a method for producing a ceramic electronic component, and a substrate for producing a ceramic green sheet.

[0010]

In order to achieve the above object, a method for manufacturing a ceramic green sheet according to the present invention comprises a method for forming a ceramic green sheet on a substrate using a dielectric paint. Wherein the substrate satisfies at least one of the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g.

A method for manufacturing a ceramic electronic component according to the present invention comprises the steps of forming a ceramic green sheet on a substrate using a dielectric coating, and firing a pre-fired element body on which the ceramic green sheets are laminated. A method for producing a ceramic electronic component having:
It is characterized by satisfying at least one of the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g.

A substrate for producing a ceramic green sheet according to the present invention is a substrate for forming a ceramic green sheet by applying a dielectric paint, and is characterized by satisfying at least one of the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g.

Preferably, the substrate satisfies the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g.

Preferably, the dielectric coating has a dielectric material, a water-soluble binder, and a solvent water.

The ceramic green sheet according to the present invention is a ceramic green sheet having a water-soluble binder, and has an average thickness of more than 120 μm.

[0016]

Conventionally, it has been considered difficult to obtain a thick green sheet (for example, over 120 μm) with a water-based dielectric paint. Therefore, in order to obtain such a thick green sheet, it has been necessary to use an organic solvent-based dielectric paint. However, when an organic solvent-based dielectric paint is used, various inconveniences such as a cost for the organic solvent and a problem of air pollution may occur.

The present inventors have paid attention to the substrate on which the coating material is applied, and as a result of intensive studies on this, as a result, they have found that a thick film sheet can be formed even using an aqueous dielectric coating material, and have reached the present invention.

In the method for producing a ceramic green sheet and the method for producing a ceramic electronic component according to the present invention,
A specific substrate is used as a medium for applying a dielectric paint when forming a ceramic green sheet. By using a specific substrate, even when a water-based dielectric paint is used, the drying speed at which moisture in the paint evaporates is increased, and the coatability during sheet forming is improved. For this reason, even with the water-based dielectric coating, a sufficiently thick film (preferably more than 120 μm, more preferably 140 μm) having the required strength and shape is required.
m or more, more preferably 160 μm or more, particularly preferably 250 μm or more)
Molding can be performed without causing cracks.

That is, according to the present invention, it is possible to form a thick-film green sheet using a water-based dielectric paint.

Examples of the ceramic electronic component include, but are not limited to, multilayer ceramic capacitors, piezoelectric elements, chip inductors, chip varistors, chip thermistors, chip resistors, and other surface mount (SMD) chip type electronic components.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention, FIG. 2 is a graph showing the relationship between the water permeability of a substrate and the limit film thickness of a green sheet,
FIG. 3 is a graph showing the relationship between the pore diameter of the substrate and the critical film thickness of the green sheet, and FIG. 4 is a graph showing the relationship between the pore amount of the substrate and the critical film thickness of the green sheet.

As shown in FIG. 1, a multilayer ceramic capacitor 1 as an example of a ceramic electronic component has a capacitor element body 10 having a structure in which interlayer dielectric layers 2 and internal electrode layers 3 are alternately stacked. At both ends of the capacitor element body 10, a pair of external electrodes 4 are formed which are electrically connected to the internal electrode layers 3 alternately arranged inside the element body 10. The shape of the capacitor element body 10 is not particularly limited, but is generally a rectangular parallelepiped. The size is not particularly limited, and may be an appropriate size depending on the application. Usually, the size is (0.6 to 5.6 mm) × (0.3 to 5.
0 mm) × (0.3 to 1.9 mm).

The internal electrode layers 3 are laminated so that each end face is alternately exposed on the surfaces of two opposing ends of the capacitor element body 10. The pair of external electrodes 4 are formed at both ends of the capacitor element body 10 and connected to the exposed end faces of the alternately arranged internal electrode layers 3 to form a capacitor circuit.

In the capacitor element body 10, outer dielectric layers 2a are arranged at both outer ends in the laminating direction of the internal electrode layer 3 and the interlayer dielectric layer 2, so as to protect the inside of the element body 10. I have.

Although the composition of the interlayer dielectric layer 2 and the outer dielectric layer 2a is not particularly limited in the present invention, it is composed of, for example, the following dielectric ceramic composition. The dielectric ceramic composition of the present embodiment has a main component containing, for example, calcium titanate, strontium titanate, and / or barium titanate.

The dielectric ceramic composition of the present embodiment may contain various subcomponents in addition to the main components. Sr, Y, Gd, Tb, Dy, V, Mo, Zn, and C are subcomponents contained in the dielectric ceramic composition together with the main component.
d, Ti, Sn, W, Ba, Ca, Mn, Mg, Cr,
Subcomponents containing at least one selected from oxides of Si and P are exemplified. By adding the sub-component, it is possible to improve the temperature characteristics, fire at a low temperature, and improve the reliability. However, in the present invention, the composition of the interlayer dielectric layer 2 is not limited to the above.

Although various conditions such as the number of layers and the thickness of the interlayer dielectric layer 2 shown in FIG. 1 may be appropriately determined according to the purpose and application, in this embodiment, the thickness of the interlayer dielectric layer 2 is , 2
It is about 50 μm. The thickness of the outer dielectric layer 2a is, for example, about 100 μm to several hundred μm.

The conductive material contained in the internal electrode layer 3 is not particularly limited, but a base metal can be used because the constituent material of the interlayer dielectric layer 2 has reduction resistance. As the base metal, Ni, Cu, a Ni alloy or a Cu alloy is preferable. When the main component of the internal electrode layer 3 is Ni, a method of firing at a low oxygen partial pressure (reducing atmosphere) is adopted so that the dielectric is not reduced. On the other hand, a method of shifting the composition ratio of the dielectric from the stoichiometric composition so as not to be reduced is employed. The thickness of the internal electrode layer 3 may be appropriately determined according to the application or the like, but is usually 0.5 to 5 μm.
m, preferably about 1 to 2.5 μm.

The conductive material contained in the external electrode 4 is not particularly limited, but is usually Cu or a Cu alloy, Ni or N
An i alloy or the like is used. In addition, Ag, Ag-Pd alloy, etc.
Of course, it can be used. In the present embodiment, inexpensive Ni, Cu, or an alloy thereof can be used.
The thickness of the external electrode 4 may be appropriately determined according to the use or the like, but is preferably about 10 to 50 μm.

Next, a method for manufacturing a multilayer ceramic capacitor according to an embodiment of the present invention will be described.

In the present embodiment, a green chip is produced by a normal printing method or sheet method using a paste, fired, and then external electrodes are printed or transferred and fired. Hereinafter, the manufacturing method will be specifically described.

First, a dielectric layer paste is prepared. In the present embodiment, the dielectric layer paste is a dielectric material,
It is composed of an aqueous dielectric paint having at least a binder resin and solvent water. If necessary, a plasticizer, a dispersant, a wetting agent, and the like are added to this paint.

Using this dielectric layer paste, the interlayer dielectric layer 2 and the outer dielectric layer 2a shown in FIG. 1 can be formed.
Since it is assumed that a green sheet having a thickness of more than 0 μm is manufactured, the following description mainly describes a case where the outer dielectric layer 2a having a large thickness is formed.

As the dielectric raw material, a raw material constituting a main component and a raw material constituting a subcomponent are used in accordance with the composition of the above-described dielectric ceramic composition.

The raw materials constituting the main components include Ti, B
An oxide of a, Sr, Ca, and Zr and / or a compound that becomes an oxide by firing is used. Raw materials constituting the sub-components include Sr, Y, Gd, Tb, Dy, V, M
o, Zn, Cd, Ti, Sn, W, Ba, Ca, Mn,
One or more, preferably three or more, single oxides or composite oxides selected from oxides of Mg, Cr, Si, Li and P and / or compounds that become oxides upon firing are used.

These raw material powders usually have an average particle size of about 0.005 to 5 μm. In order to obtain a dielectric material from such a raw material powder, for example, the following method may be used. First, starting materials are blended in a predetermined ratio, and are wet-mixed by, for example, a ball mill. Next, it is dried by a spray drier or the like and then calcined to obtain a dielectric oxide of the above formula constituting a main component. The calcination is usually performed at 500 to 1300 ° C., preferably 50 to 1300 ° C.
0 to 1000 ° C, more preferably 800 to 1000 ° C
For about 2 to 10 hours in air. Next, the material is pulverized by a jet mill, a ball mill or the like until a predetermined particle size is obtained, thereby obtaining a dielectric material. Sub-component and sintering aid (S
iO ₂ or Li ₂ O) is calcined separately from the main components, and mixed with the obtained dielectric material.

The content of the dielectric material in the water-based dielectric paint may be about 55 to 75% by weight.

The binder resin is not particularly limited as long as it is a water-soluble binder. Examples thereof include polyvinyl alcohol, cellulose, water-soluble acrylic resin, water-soluble polyvinyl acetal, water-soluble polyvinyl butyral, and water-soluble urethane resin. . The weight ratio of the binder resin to 100 parts by weight of the dielectric material may be about 4 to 8 parts by weight.

The plasticizer is not particularly limited as long as it imparts flexibility to the water-soluble binder. Examples of the plasticizer include triethanolamine (TEA), polyethylene glycol (PEG), glycerin, ethylene glycol, triethylene glycol, and the like. Examples include trimethylpropane. The weight ratio of the plasticizer to 100 parts by weight of the binder resin may be about 50 to 150 parts by weight.

The dispersant is not particularly limited as long as it disperses the powder particles so as not to condense. For example, ammonium polycarboxylate, allyl ether copolymer, sodium benzenesulfonate, polyethylene glycol type nonionic dispersion And the like. The weight ratio of the dispersant to 100 parts by weight of the dielectric material is
It may be about 0.1 to 2 parts by weight.

The wetting agent is not particularly limited as long as it improves the wettability between the powder particles and the dispersion medium, and examples thereof include a polyethylene glycol type nonionic wetting agent and a sulfonic acid type anionic wetting agent. . Dielectric material 1
The weight ratio of the wetting agent to 00 parts by weight may be about 0.1 to 2 parts by weight.

The above-mentioned dielectric material, binder resin,
The plasticizer, the dispersant, the wetting agent, and the solvent water are mixed with, for example, a ball mill to form a paste (slurry).
In addition, upon mixing, the dielectric raw material, the dispersant, and the wetting agent are primarily mixed with a small amount of solvent water, and then, the binder resin, the plasticizer, and the remaining solvent water are secondarily mixed, thereby obtaining an aqueous dielectric. A dielectric layer paste composed of a paint may be obtained.

In the present invention, the substrate used for forming the dielectric layer paste into a sheet satisfies at least one of the following characteristics.

Preferably, all of the following characteristics are satisfied.

Water permeability: more than 0 g / cm ² · s 2 g / cm
Less than ² · s, preferably 0.01 g / cm ² · s or more and less than 2 g / cm ² · s. Pore size: more than 0.5 μm and less than 11 μm, preferably 1 μm
Not less than 11 μm. Porosity: more than 0.05 cc / g and less than 0.63 cc / g;
0.1 cc / g or more and less than 0.63 cc / g.

When the water permeability of the substrate is 0 g / cm ² · s, moisture does not permeate from the substrate and it is difficult to dry.
When a sheet of a thick film (for example, more than 120 μm) is formed, cracks occur. If the water permeability of the substrate is too large, moisture easily permeates through the substrate, and the drying speed of the paint increases, so that when a thick film sheet is formed, cracks occur or the paint itself passes through the substrate. It becomes difficult to apply the paint.

If the pore diameter of the substrate is too small, moisture does not permeate from the substrate and it is difficult to dry. Therefore, when a thick film (for example, more than 120 μm) is formed into a sheet, cracks occur. If the pore diameter of the substrate is too large, moisture easily permeates through the substrate, and the drying speed of the coating material increases.Therefore, when a thick film is formed, cracks occur or the coating material itself passes through the base material. It becomes difficult to apply the paint.

If the pore volume of the substrate is too small, moisture does not permeate from the substrate and it is difficult to dry. Therefore, when a thick film (for example, more than 120 μm) is formed into a sheet, cracks occur. If the porosity of the substrate is too large, moisture easily permeates through the substrate, and the drying speed of the coating material increases.Therefore, when a thick film is formed, cracks occur or the coating material itself passes through the base material. It becomes difficult to apply the paint.

As the substrate having such specific characteristics, a commercially available product may be used. For example, “High Needs Paper (water permeability: 0.42 g / cm ² · S, manufactured by Oji Paper Co., Ltd.
Pore diameter: 5.00 μm, Pore volume: 0.45 cc /
g) "; CH185 manufactured by Oji Paper Co., Ltd. (water permeability: 2.0
0 g / cm ² · S, pore size: 11.00 μm, pore volume: 0.63 cc / g), and coated with a PVB-based resin paint (S-LEC KX-1, Sekisui Chemical Co., Ltd.)
185 paper treatment (water permeability: 0.053 g / cm ² · S,
Pore diameter: 3.65 μm, porosity: 0.34 cc /
g) ”;“ Solpore (permeability: 0.022) ”manufactured by Teijin Limited
g / cm ² · S, pore diameter: 3.00 μm, pore volume:
0.20 cc / g); Teijin Ltd. sorbore (water permeability: 0.022 g / cm ² · S, pore diameter: 3.00 μm)
m, pore volume: 0.20 cc / g), and a PVB-based resin paint (ESLEK KX-1, manufactured by Sekisui Chemical Co., Ltd.) was applied on the “solpore treatment (water permeability: 0.010 g / cm ² ···).
S, pore size: 1.40 μm, pore volume: 0.10 cc /
g) "; and the like.

In the present invention, on such a specific substrate,
For example, a dielectric layer paste is applied to a predetermined thickness by various application methods such as a doctor blade method, a gravure method, a spray method, a roll method, a nozzle method, and a wire method, and dried to form a sheet.

The internal temperature of the drying oven for drying the sheet is preferably 25 ° C. to 70 ° C. If the drying temperature is too low, drying takes time, and if the drying temperature is too high, the sheet tends to crack.

The drying temperature gradient is less than 7.5 ° C./min, preferably 0.7 ° C./min to 1.7 ° C./min, more preferably 0.7 ° C./min to 1.07 ° C./min. is there. The green sheet is placed in a drying oven by a conveying means such as a conveyor. If the conveying speed is too fast, the drying temperature gradient of the green sheet per unit time rises, and the water tends to evaporate rapidly, and the sheet tends to crack. On the other hand, if the transport speed is too slow, the drying temperature gradient of the green sheet per unit time decreases, and cracks are less likely to occur, but productivity tends to decrease.

The drying time is preferably 15 minutes to 65 minutes.
Minutes, more preferably 30 minutes to 65 minutes. If the drying time is too short, the drying temperature gradient of the green sheet per unit time will increase, and the water will rapidly evaporate, and the sheet will tend to crack. If the drying time is too long, the productivity tends to decrease.

The green sheet formed as described above is a portion constituting the outer dielectric layer 2a shown in FIG. 1, and is preferably more than 120 μm, more preferably 140 μm.
m, more preferably 160 μm or more, particularly preferably 250 μm or more.

Separately from the green sheet for the outer dielectric layer, the surface of the green sheet for the interlayer dielectric layer, which is formed to be thin to about 2 to 50 μm, has an internal electrode layer 3 to be the internal electrode layer 3 shown in FIG. The paste is applied and dried in a predetermined pattern.

The internal electrode layer paste was prepared as follows.
(See FIG. 1), and is prepared by kneading the above-mentioned conductive material and the like and an organic vehicle.

The shape of the conductive material used in producing the internal electrode paste is not particularly limited, such as a sphere or a scale, and a mixture of these shapes may be used. The average particle size of the conductive material is usually 0.1 to 1
A material having a thickness of 0 μm, preferably about 0.2 to 1 μm may be used.

The green sheets for the interlayer dielectric layer coated with the paste for the internal electrode layers are alternately laminated, and the outer dielectric layer green sheets are laminated in a single layer or multiple layers at both outer ends in the laminating direction. I do.

Next, the laminate thus obtained is
After cutting into a predetermined size of the laminate to form a green chip, binder removal processing and firing are performed. Then, heat treatment is performed to reoxidize the dielectric layers 2 and 2a.

The binder removal treatment may be performed under ordinary conditions, but when a base metal such as Ni or a Ni alloy is used as the conductor material of the internal electrode layer, it is particularly preferably performed under the following conditions. Heating rate: 5 to 300 ° C / hour, especially 10 to 50 ° C / hour, Holding temperature: 200 to 400 ° C, especially 250 to 350 ° C, Holding time: 0.5 to 20 hours, especially 1 to 10 hours, atmosphere Gas: A humidified mixed gas of N ₂ and H ₂ .

The firing conditions are preferably as follows. Heating rate: 50 to 500 ° C / hour, especially 200 to 300
° C / hour, holding temperature: 1100-1300 ° C, especially 1150-12
50 ° C., holding time: 0.5 to 8 hours, especially 1 to 3 hours, cooling rate: 50 to 500 ° C./hour, especially 200 to 300
° C / hour, atmosphere gas: humidified mixed gas of N ₂ and H ₂ , etc.

[0063] However, the oxygen partial pressure in an air atmosphere at firing ^{is, 10} -2 Pa or less, in particular ^{10 -} 2 ^~10 -8 Pa
It is preferred to carry out at. When the ratio exceeds the above range, the internal electrode layer tends to be oxidized, and when the oxygen partial pressure is too low, the conductive material of the internal electrode layer tends to be abnormally sintered and cut off.

The heat treatment after the calcination is performed at a holding temperature or a maximum temperature, preferably 1000 ° C. or more,
More preferably, it is preferable to carry out at 1000-1100 ° C. If the holding temperature or the maximum temperature during the heat treatment is less than the above range, the insulation resistance life tends to be shortened due to insufficient oxidation of the dielectric material. Not only does it decrease, but it also reacts with the dielectric substrate, which tends to shorten its life. The oxygen partial pressure during the heat treatment is an oxygen partial pressure higher than the reducing atmosphere during the firing, and is preferably 10 ⁻³ Pa to 1 P.
a, more preferably 10 ⁻² Pa to 1 Pa. Below this range, reoxidation of the dielectric layer 2 is difficult, and beyond this range, the internal electrode layer 3 tends to oxidize.

The other heat treatment conditions are preferably as follows. Holding time: 0 to 6 hours, especially 2 to 5 hours, Cooling rate: 50 to 500 ° C / hour, especially 100 to 300
° C / hour, atmosphere gas: humidified N ₂ gas, etc.

In order to humidify the N ₂ gas or the mixed gas, for example, a wetter may be used. In this case, the water temperature is preferably about 0 to 75 ° C. Further, the binder removal treatment, the sintering, and the heat treatment may be performed continuously or independently. When these are continuously performed, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of firing, firing is performed, and then the temperature is lowered to the holding temperature of the heat treatment. It is preferable to perform the heat treatment while changing the atmosphere. On the other hand, when these are performed independently, at the time of firing, the N ₂ gas or the humidified N ₂
After raising the temperature in a gas atmosphere, it is preferable to change the atmosphere and continue to further raise the temperature. After cooling to the holding temperature during the heat treatment, change to an N ₂ gas or humidified N ₂ gas atmosphere again and cool. Is preferably continued. In the heat treatment, the temperature may be raised to a holding temperature in an N ₂ gas atmosphere, and then the atmosphere may be changed, or the entire heat treatment may be performed in a humidified N ₂ gas atmosphere.

The thus obtained sintered body (element body)
10) For example, by barrel polishing, sand plasting, etc.
After polishing the end surface, baking the paste for external electrodes
The electrode 4 is formed. The firing conditions for the external electrode paste are as follows:
For example, humidified N₂And H ₂60 in a mixed gas with
It is preferable to set the temperature at 0 to 800 ° C. for about 10 minutes to 1 hour.
Good. Then, if necessary, plating or the like on the external electrode 4
Is performed to form a pad layer. In addition, external electrode
Paste is the same as the internal electrode layer paste described above.
May be prepared.

The multilayer ceramic capacitor of the present invention thus manufactured is mounted on a printed circuit board or the like by soldering or the like, and is used for various electronic devices and the like.

In the method of manufacturing a ceramic green sheet and the method of manufacturing a multilayer ceramic capacitor according to the present embodiment, a specific substrate is used as a medium for applying an aqueous dielectric paint. A sufficiently thick film (preferably 12
A ceramic green sheet having a thickness of more than 0 μm, more preferably 140 μm or more, further preferably 160 μm or more, and particularly preferably 250 μm or more can be formed without causing cracks. Therefore,
In order to form the outer dielectric layer 2a in the capacitor 1 shown in FIG. 1, it is not necessary to stack a large number of thin green sheets, which contributes to a reduction in manufacturing steps and manufacturing costs.

Further, according to the present embodiment, since no organic solvent is used in producing the ceramic green sheet, various inconveniences caused by using the organic solvent can be prevented.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and can be implemented in various modes without departing from the gist of the present invention. Of course.

For example, in the above-described embodiment, the outer dielectric layer 2a is formed using a specific substrate, but may be used for forming the interlayer dielectric layer 2 if necessary.

Further, for example, the ceramic electronic component manufactured using the specific substrate of the present invention is not limited to a multilayer ceramic capacitor having a large number of internal electrode layers 3 as shown in FIG. In FIG. 1, a large number of internal electrode layers 3 are stacked, but there are capacitors and other electronic components in which only one pair or only a plurality of pairs of internal electrodes are stacked. Also in that case, it is necessary to make the thickness of the outer dielectric layer 2a sufficient, and
Being able to be constituted by a single layer or a laminate of a plurality of green sheets, instead of a laminate of many green sheets, greatly contributes to a reduction in the number of manufacturing steps and a reduction in the manufacturing cost.

[0074]

EXAMPLES Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

[0075]Example 1 First, as a starting material base material, BaTiO₃(BT-0
5 powder / Sakai Chemical Industry Co., Ltd.). BaTiO₃
Has an average particle size of 0.86 μm and a specific surface area of BET value.
2.3m²/ G. For this base material, (B
a, Ca) SiO ₃: 1.48% by weight, Y
₂O₃: 1.01% by weight, MgCO₃: 0.72 weight
%, Cr₂O₃: 0.13% by weight and V₂
O₅: 0.045% by weight of each in a ball mill at 16:00
Wet pulverization was performed to obtain a dielectric material.

The obtained dielectric raw materials were mixed in a ball mill using zirconia balls at the compounding ratios shown below to form a slurry to obtain a coating material. That is, first, 100 parts by weight of the obtained dielectric material: ammonium polycarboxylate (dispersant / SN546 manufactured by San Nopco Co., Ltd.)
8): 2 parts by weight and polyethylene glycol type nonionic wetting agent (SN Wet 366 manufactured by San Nopco Co., Ltd.):
0.4 parts by weight and 17.5 parts by weight of solvent water (ion-exchanged water) were primarily mixed by a ball mill for 16 hours to obtain a primary mixed solution. Next, polyvinyl alcohol (binder resin / 18% aqueous solution of PVA217S manufactured by Kuraray Co., Ltd.): 6 parts by weight, triethanolamine (plasticizer / special grade TEA manufactured by Junsei Chemical Co., Ltd.): 55 parts by weight, and solvent water:
27.3 was added to the primary mixed solution by a ball mill.
Secondary mixing was performed for 6 hours to obtain a water-based dielectric paint sample.

High-needs paper as a substrate fixed on a stainless steel plate (manufactured by Oji Paper Co., Ltd., water permeability: 0.42 g /
cm ² · S, pore diameter: 5.00 μm, pore volume: 0.4
(5 cc / g), and the resulting paint samples were applied in various thicknesses using a bar coater, and then dried at 50 ° C. for 15 minutes to evaluate paint leakage during application, critical thickness, and drying speed of the paint. did.

Paint leakage at the time of application was evaluated as follows. The coating was applied to the substrate fixed on the stainless steel plate with a bar coater, and left at room temperature for 15 minutes. After that, the paint that passed through the base and adhered to the stainless steel plate was evaluated as “paint leakage”, and the paint that did not pass through the substrate and did not adhere to the stainless steel plate was evaluated as “no paint leakage”. Was evaluated. In addition, the presence or absence of paint leakage
Performed visually. As a result, there was no paint leakage.

The critical thickness was determined as follows. The coating thickness on the substrate is 50 μm, 100 μm, 120 μm,
140 μm, 160 μm, 180 μm and 250 μm
And the presence or absence of film formation after drying the sheet was evaluated.
However, when a crack occurred, it was excluded from the limit thickness. The evaluation of the critical thickness at which film formation was possible was performed visually. As a result, the limit thickness was 160 μm.

The drying speed of the paint was evaluated as follows. A paint is applied to a substrate fixed on a stainless steel plate with a bar coater so as to have a thickness of 250 μm.
Dry for 5 minutes at ° C. Here, the weight change rate when the paint weight immediately after application corresponding to a thickness of 250 μm is W1 and the paint weight after drying is W2 ((W1−W2 / W1))
× 100) was calculated. As a result, the weight change rate is 14.
6%.

The water permeability of the substrate was measured by measuring the time required when 200 g of water was filtered under a pressure of 0.1 MPa while the substrate was sandwiched between stainless steel holders KST47 (manufactured by Toyo Roshi Kaisha) with a tank. Permeability was calculated by converting per unit area to per unit time. The pore diameter and the pore volume of the substrate are measured by a mercury porosimeter (CE INSTRUME).
NTSC, PASCAL140, PASCAL44
0).

Example 2 As a substrate, a CH185 paper treatment (water permeability: 0.053 g / c) obtained by applying a PVB-based resin paint (Eslek KX-1, manufactured by Sekisui Chemical Co., Ltd.) on CH185 (manufactured by Oji Paper Co., Ltd.)
m ² · S, pore diameter: 3.65 μm, pore volume: 0.34
In the same manner as in Example 1, except for using cc / g), the paint leakage during application, the critical thickness, and the drying speed of the paint were evaluated. As a result, there was no paint leakage. The limit thickness was 180 μm. The weight change rate before and after drying with respect to the drying speed of the paint was 12.5%.

Example 3 As a substrate, Sorpore (manufactured by Teijin Limited, water permeability: 0.022)
g / cm ² · S, pore diameter: 3.00 μm, pore volume:
Except for using 0.20 cc / g), the same procedure as in Example 1 was performed to evaluate paint leakage during application, critical thickness, and drying rate of the paint. As a result, there was no paint leakage. The limit thickness was 250 μm. The weight change rate before and after drying with respect to the drying speed of the paint was 11.6%.

[0084]Example 4 As a substrate, a PVB-based resin
(Slek KX-1, Sekisui Chemical Co., Ltd.)
Sol pore treatment (water permeability: 0.010 g / cm ²・
S, pore diameter: 1.40 μm, pore volume: 0.10 cc /
g) except that g) was used.
Paint leak, critical thickness, and paint drying speed
evaluated. As a result, there was no paint leakage. Limit thickness
Was 140 μm. Drying speed of paint
The weight change rate before and after was 10.1%.

Comparative Example 1 As a substrate, PH50 (manufactured by Hokuetsu Paper Co., Ltd., water permeability: 8.0)
0 g / cm ² · S, pore diameter: 30.00 μm, pore volume: 3.00 cc / g), in the same manner as in Example 1 except for paint leakage at application, critical thickness, and drying of paint. The speed was evaluated individually. As a result, paint leakage occurred, the critical thickness could not be determined, and the rate of change in weight of the paint before and after drying could not be calculated.

Comparative Example 2 As a substrate, CH185 (manufactured by Oji Paper Co., Ltd., water permeability: 2.
(00g / cm ² · S, pore size: 11.00 μm, pore volume: 0.63 cc / g), except that the paint leakage during application, the critical thickness, and the drying of the paint were performed in the same manner as in Example 1. The speed was evaluated individually. As a result, there was no paint leakage. The limit thickness was 100 μm. The weight change rate before and after drying with respect to the drying speed of the paint was 16.0%.

COMPARATIVE EXAMPLE 3 As a substrate, a BM-2 (PET film, manufactured by Toyo Metallizing Co., Ltd., water permeability: 0 g / cm ² · S,
Except for using a pore diameter of 0.5 μm and a pore volume of 0.05 cc / g), the paint leakage during application, the critical thickness, and the drying speed of the paint were evaluated in the same manner as in Example 1. As a result, there was no paint leakage. The limit thickness is 12
It was 0 μm. The weight change rate before and after drying with respect to the drying speed of the paint was 9.0%.

The results are shown in Table 1 and FIGS.

[0089]

[Table 1]

According to Table 1 and FIG. 2, the water permeability of the substrate was 0 g.
/ Cm ² · s more than 2 g / cm ² · s, water-based ceramic green sheet thick film (over 120 μm)
It was confirmed that it could be done. From Table 1 and FIG. 3, it was confirmed that when the pore diameter of the substrate was more than 0.5 μm and less than 11 μm, the water-based ceramic green sheet could be made into a thick film (more than 120 μm). According to Table 1 and FIG. 4, when the pore volume of the substrate is more than 0.05 cc / g and less than 0.63 cc / g, the ceramic green sheet is thickened (more than 120 μm).
It was confirmed that it could be done. That is, it was confirmed that when a specific substrate was used as in this example, a thick green sheet could be formed even with an aqueous dielectric paint.

[0091]

As described above, according to the present invention, a method of manufacturing a ceramic green sheet and a method of manufacturing a ceramic electronic component, which can increase the thickness of a sheet without generating cracks even when an aqueous solvent is used. A method and a substrate for producing a ceramic green sheet can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the water permeability of a substrate and the critical film thickness of a green sheet.

FIG. 3 is a graph showing a relationship between a pore diameter of a substrate and a critical film thickness of a green sheet.

FIG. 4 is a graph showing the relationship between the amount of porosity of a substrate and the critical film thickness of a green sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 2 ... Interlayer dielectric layer 2a ... Outer dielectric layer 3 ... Internal electrode layer 4 ... External electrode 10 ... Capacitor element body

Continuation of the front page (72) Inventor Tomoko Uchida 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Shigeki Sato 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation F-term (reference) 4G030 AA04 AA07 AA10 AA12 AA16 AA19 AA22 AA37 BA09 CA08 GA14 GA20 4G031 AA03 AA04 AA06 AA08 AA11 AA16 AA30 BA09 CA08 GA04 GA06 4G052 DA02 DB02 DB10 5E001 AB03 AC04 AD04 AE00 FG00

Claims (8)

[Claims] 1. A method for producing a ceramic green sheet, wherein a ceramic green sheet is formed on a substrate using a dielectric paint, wherein the substrate satisfies at least one of the following characteristics. Sheet manufacturing method. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g. 2. The method according to claim 1, wherein the substrate satisfies the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g. 3. The method for producing a ceramic green sheet according to claim 1, wherein the dielectric paint has a dielectric material, a water-soluble binder, and a solvent water. 4. A method for manufacturing a ceramic electronic component, comprising: a step of forming a ceramic green sheet on a substrate using a dielectric paint; and a step of firing a pre-fired element body on which the ceramic green sheets are laminated. Wherein the substrate satisfies at least one of the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g. 5. The method according to claim 4, wherein the base satisfies the following characteristics. Water permeability: more than 0 g / cm ² · s 2 g / cm ² ·
s, pore diameter: more than 0.5 μm and less than 11 μm, pore volume: more than 0.05 cc / g and less than 0.63 cc / g. 6. A substrate for forming a ceramic green sheet by applying a dielectric paint to form a ceramic green sheet, wherein the substrate satisfies at least one of the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g. 7. The substrate for producing a ceramic green sheet according to claim 6, wherein the substrate satisfies the following characteristics. Water permeability: 0g / cm ² · s Ultra 2 g / cm less than ² · s, the pore diameter: less than 0.5μm super 11 [mu] m, pore volume: 0.05 cc / g and less than 0.63cc / g. 8. A ceramic green sheet having a water-soluble binder, the ceramic green sheet having an average thickness of more than 120 μm.