JP3256112B2 - Ceramic green sheet and method of manufacturing ceramic substrate using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic substrate having a small thickness and a small number of surface defects, and a ceramic green sheet used for a circuit board, a multilayer circuit board, a vibration plate, an elastic plate and the like.

[0002]

2. Description of the Related Art In order to obtain a ceramic green sheet or a ceramic substrate having a small thickness, a ceramic powder, an organic binder, an organic solvent and the like are mixed as described in Japanese Patent Application Laid-Open No. 55-134991. There is known a method of producing a slurry, filtering the ceramic slurry through a mesh net (60) shown in FIG. 6 by a suction method, and removing aggregates and the like in the ceramic slurry.

[0003]

Conventionally, ceramic substrates and ceramic green sheets having a particularly small thickness, for example, a thickness of at most 30 μm, have recently been demanded. No findings were obtained. Therefore, conventional ceramics technology has been used to reduce the size of the particles, but it is difficult to obtain products with few surface defects, and many must be disposed of as defective products. I had to.

On the other hand, ceramic powder, organic binder,
In the ceramic slurry mixed with an organic solvent, in addition to impurities, coarse aggregated particles such as coarse aggregated particles, dry solidified granular material, reaggregate, or coarse aggregated particles such as fine bubbles are usually contained. is there. In the ceramic green sheet or the ceramic substrate obtained from such a ceramic slurry, the coarse aggregated particles and the like are present as defects. As the thickness of the ceramic substrate becomes thinner, the defects become more evident and easily cause a decrease in surface smoothness, a decrease in strength, generation of cracks, a decrease in dimensional stability, a decrease in electrical insulation, a decrease in airtightness, and the like. . In the case of the reverse roll coater method, since the molding is a transfer method, a fatal defect is created on the surface of the ceramic green sheet when the coarse aggregated particles and the like are present in the ceramic slurry. In particular, in the case of a thin ceramic substrate used for a circuit board, a multilayer circuit board, a vibrating plate, an elastic plate, and the like having a thickness value of at most 30 μm, these improvements have been a problem in manufacturing technology.

According to the method described in JP-A-55-134991, a method for removing coarse aggregated particles and the like is as follows.
Although an example of passing a net of 100 to 500 mesh is disclosed, in the case of this net, 500 mesh (25
Even when using (μm opening), coarse aggregated particles of 25 μm or less cannot be removed. In addition, making the openings even smaller makes it extremely difficult to produce a mesh.
Because of clogging in a short time, it was not practically used at all. Further, in the above-mentioned method, since the organic solvent in the ceramic slurry is easily evaporated due to suction filtration, there are also problems such as generation of undesired air bubbles and partial generation of a solidified and dried product.

[0006]

Means for Solving the Problems The present invention has been made to solve the above problems, and a ceramic green sheet according to the first invention has a reduced thickness after firing.
Value for ceramic substrates whose value is at most 30 μm.
Lamix green sheet comprising ceramic particles having a sphere-equivalent diameter of primary particles of 0.01 to 0.5 μm and an average degree of cohesion of at most 10 as a ceramic component, and secondary particles having a particle diameter of 20 μm or more in volume ratio. It is characterized in that it is at most 1% and the surface roughness Ra is at most 0.2 μm.

[0007] In a preferred embodiment of the ceramic green sheet of the present invention, the main component of the ceramic particles is a material mainly composed of partially stabilized zirconia, fully stabilized zirconia, alumina or a mixture thereof, or after firing. Is formed by using a material that is used as the material of the above.

According to a second aspect of the present invention, there is provided a method for manufacturing a ceramic substrate having a thickness of at most 30 μm, the method comprising the steps of: A step of producing a ceramic slurry having a viscosity adjusted to 100 to 10,000 mPas by mixing an organic solvent, a step of removing coarse aggregated particles from the ceramic slurry, and a ceramic green sheet using the ceramic slurry by a reverse roll coater method. , And firing the ceramic green sheet so that the average crystal particle diameter of the sintered body is at most 2 μm.

As a preferable step of removing the coarse aggregated particles, a step of pressurizing the ceramic slurry and filtering through a depth type filter having a mean pore diameter of at most 100 μm is preferable.

[0010] Further, as a preferable step of removing coarse aggregated particles, at least 10
A step of applying an acceleration of 0 m / s ² to separate coarse aggregated particles is preferable.

The ceramic powder has a sphere equivalent diameter of primary particles of 0.01 to 0.5 μm and an average agglomeration degree of up to 10 μm.
It is preferable that

Here, the sphere equivalent diameter is represented by a diameter (μm) = 6 / ρS corresponding to a sphere converted from the specific surface area of the ceramic particles, and ρ is the density (g) of the ceramic particles. / Cm ³ ), and S is a specific surface area value (m ² / m) of the ceramic particles by a gas adsorption method (BET method).
g).

The average degree of agglomeration is represented by a value obtained by dividing a median diameter of a ceramic powder measured by a laser scattering method by a sphere equivalent diameter of the primary particles. In this case, a 0.2% aqueous solution of sodium hexametaphosphate 3 was used as a sample to be subjected to particle size measurement by a laser scattering method.
0 ml and 50 mg of ceramic powder were weighed, placed in a container, and dispersed for 1 minute with a homogenizer (ultrasonic vibrator). The measuring device used was LA-700 manufactured by Horiba, Ltd.

The sample for measuring the sphere equivalent diameter and average agglomeration degree of the primary particles of the ceramic green sheet was obtained by slowly heating the ceramic green sheet under an oxidizing atmosphere as shown in the profile of FIG.
By performing heat treatment at ℃, binders are sufficiently decomposed,
It was measured by the same method as above, using the ceramic powder that had been removed and powdered. In addition, the volume ratio of the secondary particles indicates the volume ratio of the total value of the particles having a particle diameter of 20 μm or more measured by a laser scattering method.

In the above-mentioned manufacturing method, the depth type filter is preferably a porous ceramic filter or a porous resin filter.

The average pore diameter of these filters is a median pore diameter measured by a mercury intrusion method. The measuring device was Carlo. An Elbe mercury intrusion porosimeter Autopore 9220 type was used.

As the organic binder, polyester acrylates such as polyvinyl butyral, ethyl cellulose, polyethyl acrylate and polybutyl acrylate, and polyester methacrylates such as polymethyl methacrylate and polybutyl methacrylate are preferable. Any soluble organic binder can be used.

In the above-mentioned production method, the viscosity was measured using a viscometer, LVT type, manufactured by BROOK FIELD, and the measurement conditions were a No. 3 rotor and a rotation speed of 12 rpm.
The temperature of the ceramic slurry of the sample was 25 ° C.

[0019]

The ceramic green sheet according to the present invention comprises, as a ceramic component, ceramic particles whose primary particles have an equivalent sphere diameter of primary particles of 0.01 to 0.5 μm and an average degree of cohesion of 10 or less. By defining the sphere equivalent diameter and the average agglomeration degree of the primary particles in a specific range in this manner, it is suitable for producing a ceramic substrate having a small thickness.

The equivalent spherical diameter of the primary particles is more preferably 0.05 to 0.3 μm, and still more preferably 0.1 to 0.2 μm.
The range of m is good. When the sphere equivalent diameter is large, the firing temperature for forming a ceramic substrate is increased, or the crystal grains grow coarsely, which is not preferable because the surface smoothness is reduced and the strength of the ceramic substrate is reduced. In addition, when the equivalent spherical diameter is small, the cohesive force between the ceramic particles becomes strong, and it becomes difficult to uniformly disperse the ceramic slurry, and the slurry properties suitable for molding cannot be obtained, so that a ceramic green sheet having a uniform thickness can be obtained. Further, coarse aggregated particles are easily formed in the slurry, and the drying shrinkage when changing from the slurry to the sheet becomes non-uniform. Further, at the time of firing, the firing shrinkage of the coarse agglomerated particles is significantly different from that of the other portions, so that the dimensional stability after firing decreases.
When the coprecipitation method is used as a powder preparation method, the sphere equivalent diameter of the primary particles can be changed, for example, by the pH, temperature, concentration, etc. of the solution at the time of coprecipitation. Depending on the baking temperature, the higher the temperature, the larger it can be. When using the solid-phase reaction method,
It depends on the particle size of the starting material powder and the calcination temperature for powder synthesis. Further, in each of the synthesis methods, the sphere equivalent diameter of the primary particles can be controlled by the conditions of the pulverizing step, the heat treatment temperature after the pulverization, and the like.

The present invention is characterized in that the average degree of agglomeration of the ceramic particles is controlled, and the maximum is preferably not more than 10, preferably 7, and more preferably 5. If the average cohesion of the ceramic particles becomes excessive, the thickness of the ceramic green sheet becomes uneven or deformed,
It is unsuitable for a ceramic substrate having a small thickness, such as cracks or a large surface roughness when the ceramic substrate is formed, and dimensional stability is reduced.

Further, the particles having a large average agglomeration degree of the ceramic particles not only cause surface defects when the substrate becomes a ceramic substrate, but also cause scratches on the surface of the ceramic green sheet when being formed by a reverse roll coater method. And other defects. Therefore, in the present invention, it is also an essential requirement that secondary particles having a particle diameter of 20 μm or more are not contained in an amount of more than 1% by volume, and secondary particles having a particle diameter of 10 μm or more, more preferably 5 μm
It is desirable that the above secondary particles do not contain more than 1% by volume, respectively. The average cohesion degree is 1
It can be controlled by the same method as that for controlling the equivalent spherical diameter of the secondary particles.

The ceramic particles of the present invention include partially stabilized zirconia, fully stabilized zirconia, alumina,
Materials containing spinel, mullite, silicon nitride, aluminum nitride, silicon carbide, titania, beryllia, or a mixture thereof as a main component, or a material that becomes such a material after firing, are used. Materials based on stabilized zirconia, alumina, or mixtures thereof are preferred. Among them, a compound such as yttrium oxide is added to zirconia, and the crystal phase is mainly tetragonal, or a mixed crystal composed of at least two or more crystal phases of cubic, tetragonal and monoclinic. It is more preferable to use zirconia whose main component is partially stabilized. In addition, the partially stabilized zirconia referred to here is a zirconium oxide (zirconia) in which a crystal phase is partially stabilized so that crystal transformation occurs only partially when heat or stress is applied. means. The above-mentioned material may contain up to 30% of a sintering aid, for example, clay, silica, magnesia, transition metal oxide and the like.

Further, it is essential that the ceramic green sheet of the present invention has a surface roughness Ra of 0.2 μm or less, preferably 0.15 μm or less, more preferably 0.10 μm or less. desirable.
The surface roughness Ra was measured using a surface roughness tester Surfcom 470A manufactured by Tokyo Seimitsu Co., Ltd.
mR 90 ° cone, cutoff value 0.80mm, trace speed 0.30mm / s, measurement length 2.5mm3
It is measured as the average value of the center line average roughness of the point measurement.

In the method of manufacturing a ceramic substrate according to the second aspect of the present invention, the viscosity is preferably adjusted when the ceramic powder is mixed with an organic binder and an organic solvent to form a ceramic slurry. Is 100 to 10000 mPa · s, more preferably 5
It is adjusted to 00 to 2000 mPa · s. The reason for this is that if the viscosity is high, it becomes difficult to remove the coarse aggregated particles in the next step of removing coarse aggregated particles, and for example, when filtering with a depth type filter, clogging may occur. This is likely to occur, and the filtration efficiency is reduced. Also, in the step of separating coarse aggregated particles by applying acceleration, the moving speed of the coarse aggregated particles is reduced, and the separation efficiency is reduced. On the other hand, if the viscosity is too low, green sheet molding becomes difficult, and the homogeneity of the ceramic slurry is reduced.

Filters can be broadly classified into surface type and depth type filters shown in FIG. 3 based on the structure of the media. The surface type refers to a type in which a medium to be filtered passes through a short distance, as typified by a screen mesh made of a stainless wire or the like. In this type, the size of the particles that can be removed is determined by the aperture of the surface. However, it has been found that clogging is easily performed in filtering a material having a small particle size as in the technical field of the present invention, and it is not practical at all.

On the other hand, filtration with a depth-type filter is also referred to as depth filtration or volume filtration, and has a certain thickness of the medium. In a preferred embodiment of the method of the present invention, the filtration through the depth type filter is used to remove coarse aggregated particles.
The embodiment will be described below with reference to FIGS.

In order to remove coarse agglomerated particles in the ceramic slurry, the ceramic slurry whose viscosity has been adjusted is pressurized, and is subjected to a depth type filter (1), for example, a filter made of porous ceramics or porous resin, according to the flow shown in the figure. Filter. The filter used here has an average pore diameter of 100 μm or less, preferably 50 μm.
m, more preferably 30 μm or less. In the present invention, the thickness (t) of the filter (1) is preferably 5 mm or more, but may be appropriately determined in consideration of the size of coarse particles to be filtered, the strength of the filter body, and the like. The pressure for pressing the slurry is desirably in the range of 0.1 to 5.0 kg / cm ² . If the pressure is too low, it takes too much time to filter the ceramic slurry. If the pressure is too high, the pores of the filter may expand or break, and particles having a predetermined particle size or more may pass. It is also preferable to subject the ceramic slurry to a vacuum degassing treatment before and after filtration.

In the embodiment of the method of the present invention, the use of the depth-type filtration is different from the surface-type filtration, and it is possible to remove particles much smaller than the average pore diameter corresponding to the opening of the filter layer main body. in spite of,
Based on the findings of the research results that resulted in less clogging and higher filtration efficiency. The difficulty of clogging is that the pores of the filter layer body are connected in a complicated manner between the front and back sides, which have a certain distance, and the relatively soft slurry layer adsorbed inside the pores causes the flow of coarse aggregated particles. It is thought that this is due to blocking.

In the step of removing coarse agglomerated particles in the present invention, at least 100 m
The step of separating coarse aggregated particles by applying an acceleration of / s ² is recommended as a mode different from the above-mentioned filtration step.
For example, an acceleration of 100 m / s ² is provided in the form of a centrifugation process as shown in FIG. By subjecting the ceramic slurry contained in the container to centrifugal separation, coarse aggregate particles such as aggregates and dried ceramic slurry can be sedimented and fixed on the bottom surface of the container and separated. The acceleration in this case is 100 m / s ² or more, preferably 1000 m / s ² or more, and more preferably 5000
m / s ² or more. Furthermore, in the filter,
When ceramic particles having an average cohesion degree of 10 or more are used, separation may be difficult due to clogging by coarse aggregate particles, but the centrifugal separation method enables separation regardless of the average cohesion degree. Since the ratio of the ceramic particles to the organic composition changes when the rate of sedimentation and fixation increases, the equivalent spherical diameter of the primary particles of the ceramic powder used is 0.01 to
It is preferable that the average agglomeration degree is 0.5 μm or less.

Next, in the step of forming a ceramic green sheet using the ceramic slurry of the present invention, a reverse roll coater method is employed. With the doctor blade method, which is widely used in sheet forming, it is difficult to form a green sheet with a thin and uniform film thickness, and traces scraped off with a blade remain on the thin sheet surface as vertical streaks. However, this causes a decrease in strength and a decrease in surface smoothness. Therefore, in order to obtain a sheet having few surface defects, molding by a reverse roll coater method is essential.

Next, in the present invention, the ceramic green sheet is fired by laminating other green sheets or independently, depending on the application, under conditions suitable for binder removal and sintering as in the prior art. Is done. In this case, it is an essential requirement that the ceramic component be fired into a sintered body having an average crystal particle diameter of at most 2 μm. Further, within a range in which the average crystal particle diameter is 2 μm at the maximum, the surface roughness Ra is set at 0.
It is preferably at most 30 μm, particularly preferably at most 0.20 μm. This is because the method for manufacturing a ceramic substrate having a small thickness as in the present invention is required to have few surface defects and to have excellent surface smoothness. The average crystal particle diameter was determined by polishing the cross section of the ceramic substrate, finishing the mirror surface, and then performing thermal etching in accordance with a conventional method to reveal the grain boundaries. Using an electron microscope, the particle number n and the area S (μm ² ) were determined. Measured, average crystal particle diameter D
(Μm) = √ (4S / πn).

The surface roughness Ra of the ceramic substrate is as follows:
Using the same surface roughness meter as the measurement of the green sheet,
5μm R90 ° cone with diamond tip, 0.80mm cut-off value, 0.30mm / trace speed
s, measured as the average value of the center line average roughness of a three-point measurement with a measurement length of 2.5 mm.

In the present invention, the following organic binders, organic solvents, and plasticizers and dispersants that can be used to improve properties are recommended. As the organic binder, polyvinyl butyral, polyester methacrylate, ethyl cellulose and the like are suitable, but any organic binder soluble in an organic solvent can be used. As organic solvents, methyl alcohol, ethyl alcohol, isopropyl alcohol, alcohols such as n-butyl alcohol, benzene, toluene, aromatic hydrocarbons such as xylene, methyl ethyl ketone, methyl isobutyl ketone, ketones such as acetone, trichloroethylene, A common organic solvent such as tetrachloroethylene or a mixed solvent thereof can be used. General plasticizers such as phthalates, sebacates, and ethylene glycol can be used. As the dispersant, a general dispersant such as a sorbitan fatty acid ester-based dispersant and a surfactant can be used.

The ceramic substrate of the present invention has a relative density of generally 90% or more, preferably 95% or more.
The above dense body, more preferably a dense body of 98% or more is desirable in terms of material properties such as strength and Young's modulus.

The method for producing a ceramic green sheet and a ceramic substrate of the present invention comprises a multilayer ceramic substrate, an IC substrate, a solid electrolyte for a fuel cell, and various sensors, actuators, oscillators, vibrators, and the like.
It can be preferably applied to a diaphragm, an elastic plate, and the like used for a display, a microphone, a speaker, a filter, and the like, and to manufacture thereof. In addition, as an application means in the above-mentioned application, not only is the ceramic green sheet used alone, but when printing on the ceramic green sheet and laminating them, or when using as a diaphragm or an elastic plate, Is used by laminating it with another ceramic green sheet as a base, and forming a passive element or an active element on a substrate.

[0037]

Next, the present invention will be described based on embodiments. (Example 1) A ceramic powder having a sphere equivalent diameter and an average cohesion degree described in the table is prepared. 100 parts by weight of partially stabilized zirconia powder containing 3 mol% of yttrium oxide as a ceramic powder, 4.5 parts by weight of dioctyl phthalate as a plasticizer, 2 parts by weight of a sorbitan fatty acid ester-based dispersant, 20 parts by weight of toluene as a solvent, isopropyl 30 parts by weight of alcohol is put into an alumina container together with a zirconia cobblestone, and mixed in a ball mill for 5 hours. Next, 9 parts by weight of a polyvinyl butyral resin, 10 parts by weight of toluene, and 10 parts by weight of isopropyl alcohol are additionally charged into the alumina container as an organic binder solution, and mixed by a ball mill for 30 hours. At this time, the viscosity of the ceramic slurry is adjusted to 1500 mPa · s. This slurry is filtered under a pressure of 1 kg / cm ² using a resin cylindrical filter (filter thickness t: 20 mm, outer diameter D ₁ : 70 mmφ, inner diameter D ₂ : 30 mmφ, filter width L: 250 mm). A ceramic green sheet having a thickness of about 10 μm was formed from the ceramic slurry thus obtained by a reverse roll coater. FIG. 1 is a schematic cross-sectional view of a filtration unit of the cylindrical depth filter device used here. The ceramic powder was prepared by calcining a raw material obtained by a coprecipitation method, pulverizing the raw material by a ball mill, and heat-treating the raw material. The sphere equivalent diameter of the primary particles depends on the calcination temperature, and can be increased as the temperature increases, and can be changed according to the conditions of the coprecipitation step, for example, pH, temperature, concentration, and the like. . Furthermore, it can be changed by the conditions of the ball mill pulverizing step and the heat treatment step. The average agglomeration degree can be changed by the processing conditions of the ball mill pulverizing step and the heat treatment step. The ceramic green sheet thus obtained was fired (in the air) at a predetermined temperature to obtain a ceramic substrate having a thickness of 7 μm.

The surface roughness Ra of the ceramic green sheet and the temperature of the ceramic green sheet at 350 ° C.
And then calcined to obtain a ceramic powder, and its sphere equivalent diameter, average agglomeration degree, and volume ratio of secondary particles were measured. Table 1 shows the results. Table 2 shows the number of defects having a size of 10 μm or more (observed by a stereoscopic microscope), surface roughness Ra, and average crystal particle diameter present on the surface of the ceramic substrate after firing.

[0039]

[Table 1]

[0040]

[Table 2]

Example 2 100 parts by weight of a partially stabilized zirconia powder containing 3 mol% of yttrium oxide as a ceramic component, 4.5 parts by weight of dioctyl phthalate as a plasticizer, 2 parts by weight of a sorbitan fatty acid ester-based dispersant, and a solvent as a solvent 20 parts by weight of toluene and 30 parts by weight of isopropyl alcohol are put into an alumina container together with zirconia balls, and mixed in a ball mill for 5 hours. next,
As an organic binder solution, 9 parts by weight of a polyvinyl butyral resin, 10 parts by weight of toluene, and 10 parts by weight of isopropyl alcohol were additionally charged into the alumina container,
Mix with ball mill for hours. At this time, the viscosity of the ceramic slurry is adjusted to 1500 mPa · s. Then
The mixture was placed in a glass container with a lid, treated with a centrifuge for 30 minutes, and a ceramic green sheet having a thickness of about 10 μm was formed from the ceramic slurry by a reverse roll coater method. The ceramic green sheet thus obtained was fired (in the air) at a predetermined temperature to obtain a ceramic substrate having a thickness of 7 μm. The results are shown in Tables 3 and 4. The evaluation method is the same as in Example 1.

[0042]

[Table 3]

[0043]

[Table 4]

Comparative Example 1 100 parts by weight of a partially stabilized zirconia powder containing 3 mol% of yttrium oxide as a ceramic powder, and dioctyl phthalate 4.5 as a plasticizer
Parts by weight, 2 parts by weight of a sorbitan fatty acid ester-based dispersant,
20 parts by weight of toluene and 30 parts by weight of isopropyl alcohol are charged together with a zirconia ball into a container made of alumina and mixed with a ball mill for 5 hours. Next, as an organic binder solution, 9 parts by weight of polyvinyl butyral resin, 10 parts by weight of toluene, 10 parts by weight of isopropyl alcohol
Additional parts by weight are charged into the alumina container and mixed with a ball mill for 30 hours. At this time, the viscosity of the ceramic slurry is adjusted to 1500 mPa · s. Then 325
The mixture was filtered through a stainless steel mesh (opening: 44 μm), and the ceramic slurry was formed into a ceramic green sheet having a thickness of about 10 μm by a reverse roll coater. The ceramic green sheet thus obtained was fired (in the air) at a predetermined temperature to obtain a ceramic substrate having a thickness of 7 μm. The results are shown in Tables 5 and 6. The evaluation method is the same as in Example 1.

[0045]

[Table 5]

[0046]

[Table 6]

(Embodiment 3) Operations are performed in exactly the same manner as in Embodiment 1 except for the following. The average pore diameter of the resin-made cylindrical filter was 30 μm. As the ceramic powder, fully stabilized zirconia powder (Sample No. 23 in Tables 7 and 8), alumina powder (No. 21), 90 parts by weight of partially stabilized zirconia powder + 10 parts by weight of alumina powder (No. 22) were used. Three types were used. The results are shown in Tables 7 and 8. The evaluation method is the same as in Example 1.

[0048]

[Table 7]

[0049]

[Table 8]

(Embodiment 4) Operations are performed in exactly the same manner as in Embodiment 2 except for the following. The acceleration due to centrifugation is 6000 m / s ² . As the ceramic powder, fully stabilized zirconia powder (Sample No. 26 in Tables 9 and 10) and alumina powder (No. 2 in Table 9).
4) Three types of 90 parts by weight of partially stabilized zirconia powder + 10 parts by weight of alumina powder (No. 25) were used.
The results are shown in Tables 9 and 10. The evaluation method is the same as in Example 1.

[0051]

[Table 9]

[0052]

[Table 10]

[0053]

As described above, in the ceramic green sheet according to the first aspect of the present invention, by controlling the sphere equivalent diameter and the average agglomeration degree of the ceramic particles, the number of surface defects is small, the smoothness is high, and A thin ceramic green sheet was obtained. In the method for manufacturing a ceramic sheet according to the second invention of the present invention, the sphere-equivalent diameter and average agglomeration degree of the ceramic particles are controlled, and coarse aggregate particles in the ceramic slurry are removed, so that surface defects are reduced and smoothness is reduced. A ceramic sheet with high properties and a thin thickness was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a filtration unit of a cylindrical depth filter device.

FIG. 2 is a perspective view of a cylindrical depth filter media.

FIG. 3 is a schematic diagram of a surface filter and a depth filter.

FIG. 4 is an explanatory diagram of a centrifugal separation process.

FIG. 5 Profile for pulverizing ceramic green sheets

FIG. 6 is a conventional surface filter filter.

[Explanation of symbols]

1: filter, 2: container A, 3: slurry supply port,
4: Slurry outlet from which aggregates were removed, 5: Container A, 1
0: slurry, 20: agglomerated particles or slurry dry matter,
30: air bubbles, 40: settled aggregates, etc., 50: filtration device, 60: net, 70: suction bottle, 80: vacuum tube,
90: A slurry from which aggregates have been removed.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takahiro Maeda 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Insulator Co., Ltd. (56) References JP-A-5-4868 (JP, A) JP-A Sho 55-133491 (JP, A) JP-A-62-278177 (JP, A) JP-A-62-186921 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B28B 1/30 101 B28B 11/02 H05K 1/03 610 C04B 35/00

Claims (6)

(57) [Claims] (1) The thickness after firing is at most 30 μm.
Ceramic green sheet for ceramic substrates
The ceramic component is composed of ceramic particles having a sphere equivalent diameter of primary particles of 0.01 to 0.5 μm and an average agglomeration degree of at most 10, and secondary particles having a particle diameter of 20 μm or more are at most 1 in volume ratio. % And the surface roughness R
A ceramic green sheet, wherein a is at most 0.2 μm. 2. The method according to claim 1, wherein a main component of the ceramic particles is partially stabilized zirconia, fully stabilized zirconia, alumina or a mixed material thereof, or a material which becomes a component thereof after firing. The described ceramic green sheet. 3. A method of manufacturing a ceramic substrate having a thickness of at most 30 μm, wherein an organic binder and an organic solvent are mixed with a ceramic powder to have a viscosity of 100 to 100 μm.
Manufacturing a ceramic slurry adjusted to 10,000 mPas, removing coarse aggregated particles from the ceramic slurry, forming a ceramic green sheet using the ceramic slurry by a reverse roll coater method, A method of manufacturing a ceramic substrate, comprising a step of firing and setting an average crystal particle diameter of a sintered body at a maximum of 2 μm. 4. The ceramic powder according to claim 1, wherein said ceramic powder is composed of ceramic particles having a sphere equivalent diameter of primary particles of 0.01 to 0.5 μm and an average degree of agglomeration of at most 10. The step of removing said coarse agglomerated particles comprises adding a ceramic slurry. 4. The method for producing a ceramic substrate according to claim 3, wherein the step of pressing is a step of filtering through a depth type filter having a mean pore diameter of at most 100 [mu] m. 5. The step of removing the coarse aggregated particles is a step of applying an acceleration of at least 100 m / s ² to the ceramic slurry to separate the coarse aggregated particles.
3. The method for producing a ceramic substrate according to item 1. 6. The ceramic powder according to claim 3, wherein the ceramic particles comprise primary particles having a sphere equivalent diameter of 0.01 to 0.5 μm and an average cohesion of at most 10.
A method for manufacturing a ceramic substrate according to claim 5.