JPH07115943B2 - Ceramic substrate processing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for processing a ceramic substrate. More specifically, the ceramics substrate is treated with a zirconia sol having a particle size not exceeding 500 mμ, and two or more substrates are superposed and heat-treated to impart smoothness to the substrate or maintain the smoothness of the substrate. At the same time, the present invention relates to a method for treating a ceramics substrate, which is characterized by reducing warpage without sticking to each other.

(Prior Art) Electronic materials, insulating materials, baking shelf board materials, and many other materials such as alumina, mullite, silica, chamotte, cordierite, zirconia, and other ceramic substrates made of many metal oxide compounds, or In the manufacture of ceramics substrates made of silicon nitride, aluminum nitride, silicon carbide, boron nitride and other non-oxidizing compounds, generally fine powder of zirconia powder is thinly applied between the substrates to correct the warpage of the finished substrate. However, several dozen sheets were piled on top of each other and a weight was placed on top, and heat treatment was performed again at 1000 ° C or higher. As a result, the spread powder bites into the substrate or forms recesses in the substrate, and the warpage of the substrate is repaired, but the smoothness is often impaired. Therefore, the number of substrates that emphasize smoothness is one or several.
There was a problem that each set had to be baked on the plane of the setter to repair the sled. In addition, even if heat treatment is required at a high temperature, the substrates stick to each other. Therefore, there is a problem that smoothness is impaired when heat treatment is performed by spreading powder.

(Problems to be Solved by the Invention) A method capable of treating a large number of substrates at a time without sticking even if two or more substrates are stacked and fired to correct the warp of the substrates and the smoothness is not impaired. The purpose is to provide.

(Means for Solving the Problems) That is, according to the present invention, a ceramic substrate is made of a zirconia sol having a particle diameter of not more than 500 mμ in a method in which two or more ceramic substrates are heat-treated and the warp of the ceramic substrate is corrected. The present invention relates to a method of processing a ceramic substrate, which is characterized by processing.

The zirconia sol used in the present invention is a sol having water and / or an organic solvent as a dispersion medium, and those obtained by a known method can be used. The organic solvent is not particularly limited, but alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol and glycerin, polyhydric alcohols, solvents such as toluene, MEK and hexane, and many other solvents such as cellosolve can be used. Zirconia sol particles having a size not exceeding 500 mμ can be used, and preferably 10 to 300 mμ.
This particle system is 20mμ in addition to those shown by the size of independent particles.
In the agglomerated particle system where the following single particles are agglomerated by several dozen or more,
The size of 500mμ can be used. A particularly preferred particle size is zirconia sol having a particle size of 10 to 200 mμ.

The ceramic substrate used in the present invention is aluminalite, silica, chamotte, cordierite, zirconia,
It is applicable to spinel and many other metal oxides, and to silicon nitride, aluminum nitride, silicon carbide boron nitride, and other non-oxidizing compounds. These ceramic substrates are generally manufactured by a conventional method such as a doctor blade method or a pressing method, but those obtained by other methods, for example, a method such as injection or extrusion slurry casting can also be used. Further, two or more types of substrates of different types may be stacked in two or more. As the method of treating the substrate with the zirconia sol that can be used in the present invention, the impregnation and lifting method and the spraying method can be preferably used, and the bar coating method and other processing methods can also be used.
After the substrate treatment as described above, the zirconia sol is dispersed in the surface as solid zirconia particles as a zirconia solid particle and reacted with a substrate compound by performing heat treatment at room temperature or by heating and drying, and the smoothness is improved by filling the concave portion with the substrate, Since the surface forms a zirconia-based material or a smooth coating containing a large amount of zirconia-based material, it has extremely high heat resistance. 1800
At temperatures below ℃, even if the substrates are stacked and fired, they do not stick to each other and give a smooth film with good releasability. The dry coating of this zirconia is 0.1-150μ, especially 0.1-80
μ is preferred.

The heat treatment conditions of these treated substrates depend on whether the substrate for treating the zirconia sol is, for example, a degreasing treatment state of a raw sheet at 600 ° C or less, a pre-sintering state of about 600 to 1100 ° C, or a state after firing at 1200 ° C or more. Although different, the heat treatment temperature may be an arbitrary temperature of 100 to 1800 ° C. depending on the purpose of using the substrate. The preferred range is 800-1600 ° C. The time of this heat treatment can be arbitrarily selected, but is generally 30 minutes to 10 hours, but is not limited to this.

In carrying out the present invention, the zirconia sol may be used in combination with several additives depending on the purpose. A surfactant and a low boiling point organic solvent may be used for improving the permeability, a leveling agent, a thickening agent, etc. may be used for improving the smoothness, and a thickening agent, a leveling agent, etc. may be used for increasing the film thickness.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 and Comparative Example 1 Five sol having 70 mμ of particle system as zirconia sol and 5 wt% of ZrO ₂ as water as a dispersion medium were prepared. Rectangular alumina substrate with remaining warp (250 m / m x 60 m / m x 0.6 m / m)
Was impregnated in the sol, pulled up in the vertical direction at a speed of 100 m / m / min, dried at room temperature for 30 minutes, and then dried at 60 ° C. for 3 hours. This operation was repeated once again. Eight substrates thus prepared were stacked, a weight of about 300 g was placed on the substrates, and the substrates were heated at 1600 ° C. for 6 hours according to a conventional method, subjected to warp correction processing, and allowed to cool. After cooling, the peeling of each sheet was good, no sticking, and no warping. The smoothness was improved to 0.15μ compared to the substrate smoothness Ra of 0.30μ which was not treated with zirconia sol.

As a comparative example, the warp correction process was performed in the same manner as the example except that the zirconia sol process was not performed, but the substrates may stick to each other, and this method cannot be used. Had to do.

In addition, when the warp was corrected by stacking the substrates, a fine zirconia powder having a particle size of 5 μ or less was thinly and evenly interleaved one by one, and the heat treatment for warp correction was performed as in the example. After cooling, the peeling of each sheet was good and the warp could be corrected, but the smoothness was not improved and the recesses were often increased.

Example 2 and Comparative Example 2 One sol having a particle system of 150 mμ and water containing 12% by weight of ZrO ₂ as a dispersion medium was prepared. Square silica substrate (80m / m
× 80m / m × 1.5m / m) Evenly spray the above sol with a spray gun.
Apply at a coating amount of 5g / m ² and immediately dry at 80 ° C for 1 hour.
It was further dried at 120 ° C. for 1 hour. Stack 25 of these boards 1
Heat treatment was performed at 200 ° C. for 2 hours. The sled decreased, and the boards did not stick together. As a comparative example, the same process as in the example was carried out except that the coating process of zirconia sol was not carried out. Was difficult.

Further, as another comparative example, ZrO ₂ was used instead of the method of the present invention.
When heat treatment was performed in the same manner as in the example except that 12% by weight of basic zirconium acetate was used, and one sheet was peeled off,
There was a substrate that was difficult to peel off, and considerable unevenness was noticeable in the coating layer on the substrate surface, and this method was not applicable to this method.

Example 3 One organosol having a particle diameter of 8 μm and containing 2% by weight of ZrO ₂ as methanol as a dispersion medium was prepared. A rectangular silicon nitride substrate (60 m / m x 80 m / m x 4 m / m) was impregnated into the sol, pulled up vertically at a rate of 100 m / m per minute, dried at room temperature for 1 hour, and then dried at 100 ° C for 2 hours. did. This operation was repeated twice. The three substrates thus prepared were stacked, a weight was placed on the stacked substrates, and the substrates were heated at 1500 ° C. for 3 hours according to a conventional method, warped, and then left to cool. After cooling, the peeling of each sheet was good, there was no sticking, there was no warp, and pore closure and smoothness were also good.

Example 4 and Comparative Example 3 One sol having a particle diameter of 25 mμ as zirconia sol and 18 wt% of ZrO ₂ as a dispersion medium of water was prepared. The total thickness of zirconia after drying is about 3μ on one side of a 50 x 50 m / m green sheet of alumina substrate made by a conventional method.
30 sheets were sprayed and dried at 40 ° C. in an air circulation dryer for 2 hours, and then 30 sheets were piled up, heated to 1600 ° C., kept at that temperature for 3 hours and allowed to cool. Each of the fired substrates thus prepared had good peelability and did not stick to each other at all. As a comparative example, the same procedure as in Example 4 was performed except that the zirconia sol was not applied. Fusing phenomenon occurred in some places on the fired substrate, which hindered peeling.

Claims (1)

[Claims] 1. A method for correcting the warp of a ceramic substrate by superposing two or more ceramic substrates on heat treatment, wherein the ceramic substrate is treated with a zirconia sol having a particle diameter not exceeding 500 mμ. Processing method.