JP2013252678A - Ceramic substrate manufacturing method and ceramic base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the damage of the bottom face of a ceramic base material, and to improve an yield, in the ceramic base material which has a plurality of substrate regions corresponding to a plurality of ceramic substrates, and in which the adjacent substrate regions can be divided.SOLUTION: A ceramic base material has a plurality of substrate regions corresponding to a plurality of ceramic substrates, and an R-face or a C-face is formed at an outside ridge corner 12 of the ceramic base material.

Description

  The present invention relates to a method for manufacturing a ceramic substrate by cleaving a ceramic base material, and a ceramic base material suitable for the method.

  Alumina ceramics are widely used as substrates for electronic components because of their characteristics such as electrical insulation and chemical stability. In order to facilitate the handling of these substrates, a large number of substrates are printed on a single large-area base material in order to improve the production efficiency of electronic components such as printing of wiring patterns and mounting of semiconductor elements later. doing. In such a substrate, break grooves (divided grooves) are formed on the surface in order to facilitate division into individual pieces. Such a dividing groove is manufactured by pressing a cutter blade or a press die on the surface of an unfired ceramic green sheet formed by a doctor blade or the like and then firing it (Patent Documents 1 and 2). 3).

JP2007-258228A Japanese Patent No. 3330104 Japanese Patent No. 3876259 JP 2001-335371 A

  In the high-power type of light emitting diode, the area of the substrate is enlarged, so that the area of the ceramic base material necessary for taking a large number of ceramic substrates is also increased. Due to the increase in size of the ceramic base material, warping and deformation due to non-uniform shrinkage increase during firing, and the quality tends to deteriorate. Further, since the size of the ceramic base material is increased, there is a problem that the strength of the base material is reduced and the ceramic base material is easily broken during printing or the like. Furthermore, since the distance between the break grooves becomes longer due to the increase in the size of each substrate, the break groove tends to be displaced from the desired line.

  In order to solve the various problems as described above, the present inventor has actually manufactured various ceramic base materials, and has conducted research by cutting them. However, in this process, I discovered a major problem that was previously overlooked. In other words, the ceramic base material is placed on the setter and fired. However, even if it is designed to suppress deformation such as warping and insufficient shrinkage as much as possible, the lower surface of the base material is now damaged. The scratches cause defects such as bleeding and defects during printing of conductors and phosphors, and linear light transmittance in members that require translucency, such as translucent alumina. As a result, it has become a defective product, resulting in a significant decrease in yield. Such a problem has not been so much a problem with a ceramic base material having a side of about 100 mm, but is easily caused by increasing the size of the ceramic base material to have a side of 120 mm or more. Therefore, it is thought that it has been overlooked conventionally.

  An object of the present invention is to provide a ceramic base material having a plurality of substrate regions corresponding to a plurality of ceramic substrates, and capable of cleaving adjacent substrate regions. It is to improve.

  The ceramic base material according to the present invention has a plurality of substrate regions corresponding to a plurality of ceramic substrates, and is a ceramic base material in which adjacent substrate regions can be cleaved, at an outer edge corner portion of the ceramic base material. An R surface or a C surface is formed.

In addition, the present invention is a ceramic base material having a plurality of substrate regions corresponding to a plurality of ceramic substrates, and the adjacent substrate regions can be cleaved, and an R-face or A molding step for obtaining a ceramic base material formed with a C-plane;
When the molded body is placed on a setter and fired to obtain a ceramic base material, a firing process in which the R or C surface is arranged on the setter side, and a plurality of substrate regions are separated by cleaving the ceramic base material And a cleaving step for obtaining a ceramic substrate.

  As a result of examining a large number of samples with respect to the case where the ceramic base material is flawed, the present inventor has found that all the flaws are concentrated on the bottom surface side of the sample. Many scratches were observed at the corners of the outer peripheral edge of the sample. This cause was estimated as follows. At the time of firing, a large amount of firing shrinkage occurs in the molded body, and the dimension in plan view is reduced. At this time, when the size of the sample was small, it was considered that the scratch was not easily generated, and when the compact was baked and contracted, it was still rubbed against the setter surface in a soft state.

  Based on this hypothesis, the inventor tried to form an R-plane or a C-plane from the surface toward the thickness direction at the corner of the ceramic base material. And when this molded object was sintered, it discovered that the flaw mentioned above was suppressed and reached | attained this invention.

(A) is the perspective view which looked at the whole external appearance of the ceramic base material 1 from the upper surface 1a side, (b) is the perspective view which looked at the whole external appearance of the ceramic base material 1 from the bottom face 1b side. 1 is a schematic perspective view showing a state where a molded body 1A is installed on a setter 10. FIG. (A) is a bottom view of the ceramic base material 21 of a comparative example, (b) is a cross-sectional view of the base material 21 of (a). FIG. 4 is an enlarged view of a portion A in FIG. (A) is a bottom view of the ceramic base material 1 of the example of this invention, (b) is a cross-sectional view of the base material 1 of (a). FIG. 6 is an enlarged view of a portion B in FIG. It is an enlarged view of the corner | angular part periphery of 1 A of base materials which concern on other embodiment. (A) is the perspective view which looked at the whole external appearance of ceramic base material 1D from the upper surface 1a side, (b) is the perspective view which looked at the whole external appearance of ceramic base material 1D from the bottom face 1b side. It is a figure which shows the measurement point of the curvature in a ceramic base material.

  As shown in FIGS. 1A and 1B, the ceramic base material 1 is divided into a plurality of substrate regions 2, and division grooves 6 are formed so as to surround each substrate region 2. On the upper surface 1a side of the base material 1, the upper surface 2a of each substrate region 2 is substantially flat. On the bottom surface 1 b side of the base material 1, a recess 4 is formed in the bottom surface 2 b of each substrate region 2, and a thick portion 5 is formed so as to surround the recess 4. A predetermined number of substrate regions 2 are arranged. An unused portion 3 that is not used as the substrate region 2 is provided on the outer edge of the base material so as to surround the substrate region 2. The thickness of the unused portion 3 is equal to or greater than the maximum thickness of the substrate region 2.

  Thus, by providing the unused portion 3 thicker than the substrate region 2 at the outer edge of the base material, it is possible to suppress cracks when handling the base material.

  From this viewpoint, it is preferable that the thickness of the unused portion is equal to or greater than the maximum thickness of the substrate region. Further, from the above viewpoint, since the effect is poor even if the thickness of the unused portion is too thick, it is preferable to set the thickness to not more than twice the maximum thickness of the substrate region.

  Further, the width of the unused portion is preferably 5 mm or more from the viewpoint of suppressing cracking of the base material. Moreover, although there is no problem if the width of the unused portion is too large, the material is wasted, so 20 mm or less is preferable.

  For example, as shown in FIG. 1, the unused portion is preferably provided so as to be connected over the entire periphery at the outer edge of the base material, whereby the effect of suppressing cracking of the base material is most remarkable.

3 and 4 show a comparative example.
A predetermined number of substrate regions 2 are formed in the base material 21, and the substrate regions are arranged at predetermined intervals, for example, vertically and horizontally. In this example, each board | substrate area | region is surrounded by the division | segmentation groove | channel 6 for elongate cleavage. Adjacent substrate regions 2 are also separated by grooves. A central portion of each substrate region 2 is thin, and a recess 4 that opens toward the bottom surface 21b is formed. The upper surface 21a is substantially flat.

  In this example, the thick part 5 is formed in each substrate region 2 so as to surround the periphery of the recess 4 over the entire circumference. Each groove 6 is formed in the thick portion 5 and is not formed in the concave portion. Through holes 7 are formed at predetermined positions in each substrate region. At the time of firing, firing is performed with the bottom surface of the molded body 30 in contact with the setter as shown in FIG.

  Here, as shown in FIG. 4, on the bottom surface 21 b side of the base material 21, the outer edge corner portion 12, the corner portion 13 facing the groove 6, and the corner portion 14 facing the recess 4 are all R-surface, C No surface is provided and no special processing is performed. When the base material 21 is placed on a setter in this state and fired, scratches may occur near the corners on the bottom surface 21b side. This scratch was particularly remarkable in the vicinity of the outer edge corner portion 12.

5 and 6 show examples of the present invention.
A predetermined number of substrate regions 2 are formed in the base material 1, and the substrate regions are arranged at predetermined intervals, for example, vertically and horizontally. In this example, each board | substrate area | region is surrounded by the division | segmentation groove | channel 6 for elongate cleavage. Adjacent substrate regions 2 are also separated by grooves. The central portion of each substrate region 2 is thin, and a recess 4 is formed that opens toward the bottom surface 1b. The upper surface 1a is substantially flat.

  In this example, the thick part 5 is formed in each substrate region 2 so as to surround the periphery of the recess 4 over the entire circumference. Each groove 6 is formed in the thick portion 5 and is not formed in the concave portion. Through holes 7 are formed at predetermined positions in each substrate region. At the time of firing, as shown in FIG. 2, firing is performed with the bottom surface of the molded body in contact with the setter 10.

  Here, as shown in FIG. 6, on the bottom surface 1 b side of the base material 1, the outer edge corner portion 12, the corner portion 13 facing the groove 6, and the corner portion 14 facing the recess 4 are all provided with an R surface. It has been. In this example, an R surface is provided at the outer edge corner also on the upper surface 1 a side of the base material 1.

  It was found that when the molded body 30 of the base material 1 was placed on the setter 10 and fired in this state, scratches near the corners described above were less likely to occur.

  In the example shown in FIG. 7, on the bottom surface 1 b side of the base material 1 </ b> A, the outer edge corner 12, the corner 13 facing the groove 6, and the corner 14 facing the recess 4 are all provided with a C-plane. ing. In this example, a C surface is provided at the outer edge corner also on the upper surface 1 a side of the base material 1.

  As shown in FIG. 8, the ceramic base material 1 </ b> D is divided into a plurality of substrate regions 2, and division grooves 6 are formed so as to surround each substrate region 2. On the upper surface 1a side of the base material 1D, the upper surface 2a of each substrate region 2 is substantially flat. On the bottom surface 1 b side of the base material 1 </ b> D, a recess 4 is formed in the bottom surface 2 b of each substrate region 2, and a thick portion 5 is formed so as to surround the recess 4. A predetermined number of substrate regions 2 are arranged. In this example, a thick unused area is not provided.

  In the case where the substrate region is subjected to countersink (thinning) and the recess is formed, the thickness of the thin portion under the recess is preferably 90% or less of the maximum thickness of the substrate region. Further, from the viewpoint of the substrate strength, the thickness of the thin portion under the recess is preferably 60% or more of the maximum thickness of the substrate region.

  In each substrate region, the width of the thick portion surrounding the recess is preferably 0.5 mm or more from the viewpoint of substrate strength.

  In the present invention, the R surface or C surface is provided at the corner of the outer edge on the bottom surface side of the base material, but the corner facing the dividing groove, the corner facing the recess, and the corner facing the through hole also have the R surface or C surface. It is preferable to provide a C-plane.

  When the R surface is provided at the outer edge corner of the base material, the dimension t12 in the thickness direction of the R surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. Further, the dimension t12 in the thickness direction of the R plane is preferably 10% or more, more preferably 20% or more of the substrate thickness T from the viewpoint of the present invention. In addition, the dimension t12 in the thickness direction of the R surface is preferably 50% or less of the substrate thickness T from the viewpoint of ease of molding. The radius of curvature R12 of the R surface at the outer corner is preferably 0.1 mm or more, and more preferably 0.2 mm or more, from the viewpoint of suppression of scratches. The curvature radius R12 is preferably 50% or less of the substrate thickness.

  When the R surface is provided at the corner 13 of the dividing groove 6, the dimension t13 in the thickness direction of the R surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. Further, the dimension t13 in the thickness direction of the R surface is preferably 10% or more, and more preferably 20% or more of the groove depth D6 from the viewpoint of the present invention.

  When the R surface is provided at the corner 14 of the recess 4, the dimension t14 in the thickness direction of the R surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. Further, the dimension t14 in the thickness direction of the R surface is preferably 10% or more, more preferably 20% or more, of the recess depth D4 from the viewpoint of the present invention.

  When the C surface is provided at the outer edge corner portion of the base material, the dimension t12 in the thickness direction of the C surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. Further, the dimension t12 in the thickness direction of the C plane is preferably 10% or more, more preferably 20% or more of the substrate thickness T from the viewpoint of the present invention. In addition, the dimension t12 in the thickness direction of the C surface is preferably 50% or less of the substrate thickness T from the viewpoint of ease of molding.

  When the C surface is provided at the corner 13 of the dividing groove 6, the dimension t13 in the thickness direction of the C surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. Further, the dimension t13 in the thickness direction of the C surface is preferably 10% or more, and more preferably 20% or more of the groove depth D6 from the viewpoint of the present invention.

  When the C surface is provided in the corner portion 14 of the recess 4, the dimension t14 in the thickness direction of the C surface is preferably 0.1 mm or more, and more preferably 0.2 mm or more from the viewpoint of the present invention. In addition, from the viewpoint of the present invention, the dimension t14 in the thickness direction of the C surface is preferably 10% or more, and more preferably 20% or more of the recess depth D4.

  The material of the ceramic base material is not particularly limited as long as it is a ceramic used in an electronic component, such as alumina, magnesia, silica, yttria, silicon nitride, boron nitride, titanium nitride, boron nitride aluminum nitride, aluminum oxynitride, spinel, An example is yttrium-aluminum garnet.

  The present invention is particularly suitable for dense alumina, particularly translucent alumina. Hereinafter, a ceramic substrate made of translucent alumina will be described.

  Translucent ceramics, particularly translucent alumina, can be used, for example, as a diffusing plate for a light emitting diode element, which can dramatically extend the life of the light emitting diode element.

  The thickness of the ceramic substrate is preferably 0.05 mm or more and 2 mm or less. If the diffusing plate is too thin, it will be easily broken by impact, or the ratio of linearly transmitted light will be too high, resulting in insufficient light diffusion. When the ceramic substrate is too thick, the total light transmittance is lowered.

  The linear transmittance in the visible light region of the translucent ceramic substrate is preferably 65% or less, and more preferably 10% or less, for light diffusion. The total light transmittance of the translucent ceramic substrate is preferably 90% or more from the viewpoint of luminous efficiency.

  The crystal grain size of the ceramic constituting the translucent ceramic substrate is not particularly limited, but from the viewpoint of obtaining appropriate translucency, it is preferably 0.1 μm or more, and more preferably 1 μm or more. The crystal grain size of the ceramic is preferably 100 μm or less, and more preferably 40 μm or less.

  Further, the relative density of the ceramics constituting the translucent ceramic substrate is preferably 98% or more, and more preferably 99% or more, from the viewpoint of ensuring translucency. The pores in the ceramic scatter incident light and significantly reduce the total light transmittance.

The method for forming the ceramic substrate is not particularly limited, and may be any method such as a doctor blade method, an extrusion method, or a gel cast method. Particularly preferably, the ceramic substrate is manufactured using a gel cast method. In a preferred embodiment, a slurry containing a ceramic powder, a dispersion medium, and a gelling agent is cast, and the slurry is gelled to obtain a molded body. No. 2001-335371).
In the case of forming a groove by pressing a cutter blade or a press die on a conventional unfired green sheet, a fine crack may enter the bottom of the groove and the break strength may become unstable. This can be avoided by forming the divided groove shape by the protrusions formed on the mold.

Particularly preferably, a raw material in which an auxiliary of 150 to 1000 ppm is added to high-purity alumina powder having a purity of 99.9% or more (preferably 99.95% or more) is used. Examples of such high-purity alumina powder include high-purity alumina powder manufactured by Daimei Chemical Co., Ltd.
As the above-mentioned auxiliary agent, magnesium oxide is preferable, but ZrO ₂ , Y ₂ O ₃ , La ₂ O ₃ ,
Sc ₂ O ₃ can also be exemplified.

The average particle size of the ceramic raw material powder is not particularly limited, but is preferably 0.5 μm or less, and more preferably 0.4 μm or less, from the viewpoints of densification during low temperature sintering and improvement of translucency. More preferably, the average particle size of the ceramic raw material powder is 0.3 μm or less (primary particle size). The lower limit of the average particle size is not particularly limited. The average particle diameter of the raw material powder can be determined by direct observation of the raw material powder by SEM (scanning electron microscope).
The average particle diameter here is n = the value of (longest axis length + shortest axis length) / 2 of primary particles excluding secondary agglomerated particles on an SEM photograph (magnification: X30000, arbitrary two fields of view). It is an average value of 500.

Examples of the gel casting method include the following methods.
(1) Along with inorganic powder, a prepolymer such as polyvinyl alcohol, epoxy resin, phenol resin, or the like, which becomes a gelling agent, is dispersed in a dispersion medium together with a dispersing agent to prepare a slurry. The slurry is solidified by crosslinking and gelation.
(2) The slurry is solidified by chemically bonding an organic dispersion medium having a reactive functional group and a gelling agent.

  The above-described C surface and R surface can be formed with high precision if a form corresponding to the inner surface of the gel casting mold is provided.

  The setter used for firing is formed of a material that can withstand the conditions during firing. For example, in the case of translucent ceramics, a material that can withstand a high temperature of 1800 ° C. or higher in a hydrogen atmosphere is preferable. From this viewpoint, the setter is made of a refractory metal such as molybdenum, tungsten, or an alloy thereof. Alumina may become brittle even if it adheres to the molded body or grows depending on the firing temperature.

Example 1
A base material 1 as described with reference to FIGS. 1, 5, and 6 was manufactured.
Specifically, 100 parts by weight of alumina powder as a raw material powder and 0.025 part by weight of magnesia, 30 parts by weight of a polybasic acid ester as a dispersion medium, 4 parts by weight of MDI resin as a gelling agent, and Marialim AKM0351 (as a dispersing agent) (Product name, manufactured by Nippon Oil & Fat Co., Ltd.) 2 parts by weight and a mixture of 0.2 part by weight of triethylamine as a catalyst were used. This slurry was cast in an aluminum alloy mold at room temperature, left at room temperature for 1 hour, solidified, and then released. Furthermore, it was left at room temperature and then at 90 ° C. for 2 hours to obtain a substrate-like powder compact. This was calcined at 1200 ° C. in the atmosphere to obtain a calcined body. Subsequently, it was baked at 1800 ° C. in an atmosphere of hydrogen: nitrogen = 3: 1 to make it dense and translucent.

Each dimension is as follows.
Base material dimensions: 120mm x 120mm
Base material thickness: 1mm
Unused part 3 width: 10 mm
Unused part 3 thickness: 1 mm
Divided groove depth: 0.36 mm
The thickness t12 of the R surface of the outer corner 12 is 0.1 mm.
The radius of curvature R12 of the R surface of the outer corner 12 is 0.1 mm.
The concave surface 4 and the R and C surfaces of the corner 13 facing the dividing groove were not provided.

  In 10 samples of the obtained base material, scratches with a depth of about 0.1 mm were generated on 2 samples. Moreover, when the curvature of the base material was measured, it was 0.1 mm. As a method for measuring warpage, a difference between the maximum value and the minimum value when a substrate is placed on a surface plate and the height of nine points on the specified substrate is measured with a height gauge is taken as a measured value of warpage (FIG. 9). reference). Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 2)
In the same manner as in Example 1, a base material 1A shown in FIGS. 1, 5, and 7 was produced. However, the thickness t12 of the R surface of the outer edge corner portion 12 was 0.2 mm, and the curvature radius R12 was 0.2 mm.

  In 10 samples of the obtained base material, scratches with a depth of about 0.1 mm were generated on one sample. Moreover, when the curvature of the base material was measured, it was 0.1 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 3)
In the same manner as in Example 1, a base material 1A shown in FIGS. 1, 5, and 7 was produced. However, the outer edge corner portion 12 was not provided with an R surface, and a C surface was provided instead. The inclination angle of the C plane is 45 °. Further, the thickness t12 of the C surface of the outer edge portion 12 is 0.2 mm.

  In 10 samples of the obtained base material, scratches with a depth of about 0.1 mm were generated on one sample. Moreover, when the curvature of the base material was measured, it was 0.11 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Comparative Example 1)
In the same manner as in Example 1, the base materials shown in FIGS. 1, 3, and 4 were produced. The production conditions were the same as in Example 1, except that the R and C surfaces of the outer corner 12 were not provided.

  In 10 samples of the obtained base material, scratches having a depth of about 0.1 mm were generated on 5 samples. Moreover, when the curvature of the base material was measured, it was 0.15 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

Example 4
In the same manner as in Example 1, the base materials shown in FIGS. 1, 5, and 6 were produced. The production conditions are the same as in Example 1. However, the recessed part 4 was provided in the board | substrate area | region, and the thickness of the recessed part was 0.6 mm. The corner surface 14 facing the recess 4 was not provided with an R surface and a C surface.

  In 10 samples of the obtained base material, shallow scratches of about 0.005 mm were generated on one sheet. Moreover, when the curvature of the base material was measured, it was 0.06 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 5)
In the same manner as in Example 4, the base materials shown in FIGS. 1, 5, and 6 were produced. The production conditions are the same as in Example 1. However, an R surface is provided at the corner 14 facing the recess 4, the thickness t14 of the R surface is 0.2 mm, and the curvature radius R14 is 0.2 mm.

  In the 10 samples of the base material obtained, no scratches were observed. Moreover, when the curvature of the base material was measured, it was 0.04 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 6)
In the same manner as in Example 3, the base materials shown in FIGS. 1, 5, and 6 were produced. The production conditions are the same as in Example 1. However, the thickness of the unused part 3 of the outer peripheral part of the base material was 2 mm.

  In 10 samples of the obtained base material, the generation of scratches was observed on one sheet. Moreover, when the curvature of the base material was measured, it was 0.06 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 7)
In the same manner as in Example 3, the base materials shown in FIGS. 1, 5, and 6 were produced. The production conditions are the same as in Example 1. However, the R surface is provided at the corner 13 facing the dividing groove, the thickness t13 of the R surface is 0.2 mm, and the curvature radius R13 is 0.2 mm.

  In the 10 samples of the base material obtained, no scratches were observed. Moreover, when the curvature of the base material was measured, it was 0.12 mm. Furthermore, it did not come off from the dividing groove at the time of cleaving and cracked.

(Example 8)
In the same manner as in Example 2, the base material shown in FIGS. 1 and 5 was produced. The production conditions are the same as in Example 1. However, the thickness t12 of the R surface of the outer edge corner portion 12 was 0.5 mm, and the curvature radius R12 was 0.5 mm.

  In 10 samples of the obtained base material, generation of shallow scratches was observed on one sheet. Moreover, when the curvature of the base material was measured, it was 0.1 mm.

Example 9
In the same manner as in Example 2, the base material shown in FIGS. 1 and 5 was produced. The production conditions are the same as in Example 1. However, the thickness t12 of the R surface of the outer edge corner portion 12 was 0.6 mm, and the curvature radius R12 was 0.6 mm.

  In 10 samples of the obtained base material, generation of shallow scratches was observed on one sheet. Moreover, when the curvature of the base material was measured, it was 0.1 mm. However, chipping occurred in a part of the outer edge of the two samples of the obtained base material.

(Comparative Example 2)
In the same manner as in Example 2, the base materials shown in FIGS. 1 and 5 were produced. The production conditions are the same as in Example 1. However, the thickness of the unused portion 3 of the outer peripheral portion of the base material was 2.5 mm, and the R and C surfaces of the outer edge corner portion 12 were not provided.

As a result, two of the ten samples were broken at the dividing groove during production.
In eight samples of the obtained base material, scratches having a depth of about 0.1 mm were generated on four sheets. Moreover, when the curvature of the base material was measured, it was 0.1 mm.

(Comparative Example 3)
A base material shown in FIGS. 1 and 5 was produced in the same manner as in Example 5. The production conditions are the same as in Example 1. However, the recessed part 4 was provided in the board | substrate area | region, the thickness of the recessed part was 0.4 mm, and the R surface and C surface of the outer edge corner | angular part 12 were not provided.

As a result, two of the ten samples were broken at the dividing groove during production.
In eight samples of the obtained base material, scratches having a depth of about 0.1 mm were generated on four sheets. Moreover, when the curvature of the base material was measured, it was 0.04 mm.

(Comparative Example 4)
In the same manner as in Example 2, the base material shown in FIGS. 1 and 5 was produced. The production conditions are the same as in Example 1. However, the unused part was not provided in the outer peripheral part of the base material (see FIG. 8). Further, the R and C surfaces of the outer edge corner portion 12 were not provided.

As a result, three of the ten samples were broken at the dividing groove during production.
In seven samples of the obtained base material, scratches having a depth of about 0.1 mm were observed in three samples. Moreover, when the curvature of the base material was measured, it was 0.1 mm.

  The breakdown and evaluation of Examples and Comparative Examples are shown in Tables 1 and 2 described later.

Claims (14)

  A ceramic base material having a plurality of substrate regions corresponding to a plurality of ceramic substrates, wherein the substrate region is cleaved, and an R surface or a C surface is formed at an outer edge corner portion of the ceramic base material. A ceramic base material characterized in that   2. The ceramic base material according to claim 1, wherein a thickness of the R surface or the C surface is 0.1 mm or more and 50% or less of a thickness of the ceramic base material.   The ceramic base material according to claim 1, wherein a concave portion is formed in each ceramic substrate region.   The ceramic base material according to claim 3, wherein an R surface or a C surface is formed at corners around the recess.   The outer edge portion of the ceramic base material is provided with an unused portion that is not used as the ceramic substrate region, and the thickness of the unused portion is equal to or greater than the maximum thickness of the ceramic substrate region. The ceramic base material according to any one of claims 1 to 4.   The ceramic base material according to any one of claims 1 to 5, wherein the plurality of substrate regions are divided by dividing grooves.   The ceramic base material according to claim 6, wherein an R surface or a C surface is formed at a corner of the dividing groove.   The ceramic base material according to any one of claims 1 to 7, wherein the ceramic base material is made of translucent alumina. A ceramic base material having a plurality of substrate regions corresponding to a plurality of ceramic substrates, wherein the substrate region is cleaved, and an R surface or a C surface is formed at an outer edge corner portion of the ceramic base material. A molding process for obtaining a molded body of a ceramic base material,
When the molded body is placed on a setter and fired to obtain the ceramic base material, the firing step of placing the R surface or C surface on the setter side, and cleaving the ceramic base material A method for producing a ceramic substrate, comprising a cleaving step of separating a plurality of substrate regions to obtain a ceramic substrate.   The method according to claim 9, wherein in the molding step, the molded body is molded by a gel casting method using a molding die having a molding surface corresponding to the R surface or the C surface.   The method according to claim 9 or 10, wherein a concave portion is formed in each ceramic substrate region.   The outer edge portion of the ceramic base material is provided with an unused portion that is not used as the ceramic substrate region, and the thickness of the unused portion is equal to or greater than the maximum thickness of the ceramic substrate region. Item 12. The method according to any one of items 9 to 11.   The plurality of substrate regions are divided by dividing grooves, and the ceramic base material is cleaved along the dividing grooves in the cleaving step, according to any one of claims 9 to 12. The method described.   The method according to claim 9, wherein the ceramic matrix is made of translucent alumina.

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