JP2003292372A - Ceramic sintered compact and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic sintered compact having a small thermal expansion coefficient and a large value obtained by dividing its Young's modulus by its density, and to provide a producing method therefor. <P>SOLUTION: The sintered compact comprises cordierite of 90 to 99.8 vol.% and mullite of 0.2 to 10 vol.%. Both contents can be measured by an X-ray diffraction method, and the ratio of the peak strength of the mullite crystal (110) plane to that of the cordierite crystal (110) plane is 0.2 to 20. The sintered compact has a density of ≥2.48 g/cm<SP>3</SP>, and the average particle diameter of the cordierite crystal contained is ≤2 μm. The sintered compact has the thermal expansion coefficient of -0.2 to 0.2 ppm/K, and the value obtained by dividing its Young's modulus by its density is ≥54.3 GPa/g/cm<SP>3</SP>. The sintered compact is produced by mixing the powder, or the like, of oxides of Mg, Si, and Al so that cordierite and mullite are contained according to the above contents and then burning the mixture. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ceramic sintered body and a method for manufacturing the same. More specifically, by dispersing a specific amount of mullite in cordierite,
The present invention relates to a ceramic sintered body having a low thermal expansion and a large value obtained by dividing Young's modulus by density (hereinafter, referred to as "specific rigidity") and a method for manufacturing the same. The present invention relates to a ceramic part for semiconductor manufacturing equipment, a ceramic part for precision control machines,
It is used for ceramic parts for optical devices and catalyst carriers.

[0002]

2. Description of the Related Art Lithium aluminosilicate ceramics such as aluminum titanate, eucryptite, β-spodumene and petalite, and magnesium aluminosilicate ceramics such as cordierite have been known as low thermal expansion ceramics. There is. This aluminum titanate or lithium aluminosilicate ceramics has a small coefficient of thermal expansion, but since it has a small Young's modulus, it is easily deformed by an external force or its own weight. Therefore, its application to precision machine parts and optical equipment parts that are sensitive to dimensional changes and shape changes is limited. On the other hand, cordierite has been conventionally applied to filters, honeycombs, refractories, etc. as a low thermal expansion ceramics sintered body. But,
These are porous bodies and have a Young's modulus of 70 to 90 G
It is as small as Pa. The thermal expansion coefficient is 0.5 ppm /
It is not as small as K. Up to now, there has been known a method of coexisting a petalite phase or a β-spodumene phase in order to obtain a dense cordierite having a small thermal expansion coefficient (see, for example, Patent Document 2). However, by this method, a cordierite sintered body having a sufficiently small thermal expansion coefficient has not been obtained. Further, a technique of adding a rare earth element in order to obtain a cordierite sintered body having a small porosity and a small thermal expansion coefficient is known (for example, refer to Patent Document 1). Even in this case, the thermal expansion coefficient cannot be said to be sufficiently small.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 10-53460

[Patent Document 2] Japanese Patent Laid-Open No. 11-209171

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems, and to provide a ceramic sintered body having a low thermal expansion and a high specific rigidity, and a method for producing the same.

[0005]

The ceramic sintered body of the present invention has a cordierite content of 90 to 90% when the total content of cordierite and mullite is 100% by volume.
It is characterized by being composed of 99.8% by volume and 0.2 to 10% by volume of mullite and having a density of 2.48 g / cm ³ or more. In addition, other ceramics sintered body of the present invention,
The ratio of the peak intensity value B of the (110) plane of the cordierite crystal to the peak intensity value A of the (110) plane of the mullite crystal, which is composed of cordierite and mullite and is measured by an X-ray diffraction method [the above C (hereinafter, referred to as “peak intensity ratio”) obtained by the calculation formula (1)] of 0.
2 to 20 and the density is 2.48 g / cm ³ or more. In the present invention and other inventions, it is possible to provide a ceramics sintered body having an average particle diameter of cordierite crystals of 2 μm or less. Furthermore, 20-25
Coefficient of thermal expansion measured at ° C is -0.2 to 0.2 ppm / K
And a ceramics sintered body having a specific rigidity of 54.3 GPa / g / cm ³ or more. Also,
This ceramic sintered body is a member for semiconductor manufacturing equipment,
It can be a member for a vacuum chuck and a member for an electrostatic chuck.

The method for producing a ceramics sintered body according to the present invention comprises (1) at least one of Mg oxide powder and Mg compound powder which is heated to become Mg oxide, Al oxide powder and heated. Mixing at least one of Al compound powders that become Al oxides with at least one of Si oxide powders and Si compound powders that become Si oxides when heated, or (2) Mg , Al, Si
Or a mixture of two or more of the complex oxide powders of
(3) The total content of cordierite and mullite is obtained by mixing at least one of the metal oxide powders and the metal compound powders and at least one of the metal composite oxide powders. Is 100% by volume, the firing is performed so that cordierite is 90 to 99.8% by volume and mullite is 0.2 to 10% by volume. In this manufacturing method, the ceramics sintered body has a coefficient of thermal expansion of −0.2 to 0.2 ppm / K measured at 20 to 25 ° C. and a specific rigidity of 54.3 GPa / g / cm ³ or more. be able to. In the present invention,
When the coefficient of thermal expansion is less than 0 ppm / K, it means that the sintered body undergoes thermal contraction.

[0007]

The present invention will be described in detail below.
The ceramic sintered body of the present invention is made of cordierite (2
MgO.2Al ₂ O ₃ .5SiO ₂ ) and mullite (3
When the total content of (Al ₂ O ₃ .2SiO ₂ ) is 100% by volume, it is composed of 90 to 99.8% by volume of cordierite and 0.2 to 10% by volume of mullite. The cordierite content is 90-99.8% by volume, preferably 92-99.5% by volume, more preferably 95-9.
It is 9.3% by volume, and more preferably 95-99.2% by volume. When the content is less than 90% by volume, the specific rigidity increases, but the thermal expansion coefficient also increases, which is not preferable. Further, when the content exceeds 99.8% by volume, a spinel phase or a glass phase having a large thermal expansion coefficient, a cristobalite phase having a small Young's modulus, and the like are precipitated, so that the thermal expansion coefficient becomes large and the specific rigidity further becomes small. Not preferable. Here, the "volume%" is the total volume of cordierite and mullite produced by the reaction of the raw material powder during firing to be 1
The volume% occupied by each when the volume is 00% is shown.

The content of the mullite is 0.2 to 10% by volume, preferably 0.5 to 8% by volume, more preferably 0.7 to 5% by volume, still more preferably 0.8 to 5% by volume. %. If the content is less than 0.2% by volume, a spinel phase or a glass phase having a large coefficient of thermal expansion, a cristobalite phase having a small Young's modulus, etc. are precipitated, so that the coefficient of thermal expansion is increased and the specific rigidity is further reduced. Not preferable. Further, if the content exceeds 10% by volume, the specific rigidity increases, but the thermal expansion coefficient also increases, which is not preferable. In addition, normally, in this sintered body, the crystal phase detected by X-ray diffraction measurement is composed only of a cordierite phase and a mullite phase. In addition to the above cordierite and mullite, trace amounts of other components (inevitable impurities in production, other components) may be contained as long as they do not affect the density, the coefficient of thermal expansion and the specific rigidity. .

Another ceramics sintered body of the present invention is composed of cordierite and mullite and has a peak intensity ratio of 0.2 to 20, preferably 0.5 to 16, and more preferably 0.7 to. 10, more preferably 0.8 to 10. When the peak intensity ratio is less than 0.2, a spinel phase or a glass phase having a large thermal expansion coefficient, a cristobalite phase having a small Young's modulus, and the like are deposited, so that the thermal expansion coefficient becomes large and the specific rigidity becomes small, which is preferable. Absent.
When the peak intensity ratio exceeds 20, the specific rigidity increases, but the thermal expansion coefficient also increases, which is not preferable. In addition, normally, in this sintered body, the crystal phase detected by X-ray diffraction measurement is composed only of a cordierite phase and a mullite phase. In addition to the above cordierite and mullite, trace amounts of other components (inevitable impurities in production, other components) may be contained as long as they do not affect the density, the coefficient of thermal expansion and the specific rigidity. .

The densities of the ceramics sintered bodies of both the above inventions are 2.48 g / cm ³ or more, and preferably 2.4.
It is 9 / cm ³ or more, more preferably 2.50 / cm ³ or more. When this density is less than 2.48 g / cm ³ ,
It is not preferable because a large Young's modulus cannot be obtained and the specific rigidity becomes small. Further, since the number of pores increases, it is difficult to obtain surface smoothness when the surface is polished.

The average particle size of the cordierite crystals contained in the above ceramic sintered body is preferably 2 μm or less, more preferably 1.9 μm or less, and further preferably 1.8 μm or less. Since cordierite crystals have different coefficients of thermal expansion between the a-axis and the c-axis, if they exceed 2 μm, microcracks will occur in the sintered body during the firing process due to this difference in thermal expansion, and the specific rigidity of the resulting ceramics will be low. Therefore, it is not preferable.

The above ceramics sintered body has a temperature of 20 to 25 ° C.
The coefficient of thermal expansion measured by is preferably -0.2 to 0.2 p
pm / K, more preferably -0.16 to 0.16 ppm
/ K, more preferably -0.11 to 0.11 ppm /
K, particularly preferably -0.08 to 0.08 ppm / K. The specific rigidity is preferably 54.3 GPa / g /
cm ³ or more, more preferably 54.6 GPa / g / cm
³ or more, more preferably 54.8 GPa / g / cm ³ or more, and particularly preferably 54.9 GPa / g / cm ³ or more. Of these, the coefficient of thermal expansion is preferably -0.2 to
0.2 ppm / K and specific rigidity 54.3 GPa / g /
cm ³ or more, more preferably a thermal expansion coefficient of −0.16 to
0.16 ppm / K and specific rigidity 54.6 GPa / g
/ Cm ³ or more, more preferably a coefficient of thermal expansion of −0.11.
~ 0.11 ppm / K and specific rigidity of 54.8 GPa /
g / cm ³ or more, particularly preferably a coefficient of thermal expansion of −0.0.
8 to 0.08 ppm / K and specific rigidity of 54.9 GPa
/ G / cm ³ or more.

Further, depending on the content of mullite, as shown in FIG. 1, the coefficient of thermal expansion and the specific rigidity are as follows.
(4) is preferred. (1) When the mullite is 0.2 to 10% by volume, the coefficient of thermal expansion is -0.03 to 0.20 ppm / K and the specific rigidity is 54.4 to 56.6 GPa / g / cm ³ (2) When the content of mullite is 0.5 to 8% by volume, the coefficient of thermal expansion is -0.03 to 0.16 ppm / K and the specific rigidity is 5
4.7-56.5 GPa / g / cm ³ (3) When mullite is 0.7-5% by volume, the coefficient of thermal expansion is −0.03 to 0.08 ppm / K and the specific rigidity is 5
4.9-56.0 GPa / g / cm ³ (4) When mullite is 0.8-5% by volume, the coefficient of thermal expansion is −0.03 to 0.08 ppm / K and the specific rigidity is 5
5.0-56.0 GPa / g / cm ³

The method for producing the ceramic sintered body of the present invention will be described below. In the manufacturing method of the present invention, as raw material powder, at least one of Mg oxide powder and Mg compound powder that is heated to become Mg oxide, Al oxide powder, and Al that is heated to become Al oxide. At least one of the compound powders is mixed with at least one of the Si oxide powder and the Si compound powder that is heated to form the Si oxide. Each of these compounds may be a compound that becomes an oxide when heated, and examples thereof include carbonates, hydrogen carbonates, hydroxides and nitrates of the respective metals. In addition to the metal oxide powders and the metal compound powders, two or more kinds of the composite oxide powders of the metals (Mg, Al, Si) can be mixed and used. Examples of the composite oxide powder include powders of cordierite, mullite, and other aluminosilicates. Further, at least one of the above metal oxide powders and each of the metal compound powders and at least one of the above metal composite oxide powders can be mixed and used. For example, one or more powders of cordierite, mullite and other aluminosilicates,
One or more powders of magnesia, magnesium carbonate, alumina, aluminum hydroxide, silica and the like can be used. Moreover, a calcined powder can be used as the raw material powder.

The average particle size of each powder is preferably 2.
It is 0 μm or less, more preferably 1.9 μm or less, still more preferably 1.8 μm or less. If it exceeds 2.0 μm, a sintered body having a large Young's modulus cannot be obtained, and the specific rigidity becomes small, which is not preferable. The above-mentioned metal oxide powders and the like react with each other during the firing and the cordierite phase 90 to 9
Weigh and mix so that a sintered body composed of 9.8% by volume and 0.2 to 10% by volume of mullite phase is obtained. Usually, in this sintered body, the crystal phase detected by X-ray diffraction measurement is composed only of the cordierite phase and the mullite phase. The density,
As long as it does not affect the coefficient of thermal expansion and the specific rigidity, a small amount of other raw materials (inevitable impurities in production, other raw materials) that compose other than the above cordierite phase and mullite phase are mixed. You can also Thereafter, the mixture is usually used for molding. In the above, the shape, size, etc. of the molded body are not particularly limited, and the molding method thereof is also not particularly limited. Then, by firing this molded body, a ceramics sintered body is obtained. Firing is usually 1300 to 1450 ° C in a predetermined atmosphere
For 1 to 5 hours. The firing atmosphere is not limited, and is usually an air atmosphere, but firing in an inert gas atmosphere such as argon, vacuum, or a non-oxidizing atmosphere such as nitrogen gas is also possible. Further, this sintered body is usually obtained by pressureless firing, but it is also possible to perform HIP treatment after pressureless sintering in order to obtain a denser sintered body. Further, pressure sintering such as HP (hot press) is also possible. The above-mentioned thermal expansion coefficient and specific rigidity can be applied to the ceramics sintered body manufactured by this manufacturing method.

The ceramic sintered body of the present invention and the other ceramics of the present invention are useful as a member for a semiconductor manufacturing apparatus, a member for a vacuum chuck, and a member for an electrostatic chuck. By adopting this ceramic sintered body as a member for a semiconductor manufacturing apparatus used for manufacturing a semiconductor wafer, for example, it is possible to suppress deformation of the apparatus due to heat and obtain a semiconductor wafer with excellent dimensional accuracy. You can Further, for example, by adopting as a member for a vacuum chuck used for manufacturing a semiconductor wafer, deformation of the member due to heat can be suppressed, and a semiconductor wafer having excellent dimensional accuracy can be obtained. Further, this ceramic sintered body is, for example,
It can also be used as a member for an electrostatic chuck used for holding a wafer by Coulomb force.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples. (1) Preparation of Ceramic Sintered Body A predetermined amount of magnesia powder, silica powder, alumina powder, and mullite powder was weighed so that commercially available cordierite powder had the composition shown in Table 1, and high-purity alumina ball stone ( Wet grinding was carried out using water having a purity of 99.9% or more) as a solvent. The average particle size of the powder after pulverization was 1.7 μm. Then, a binder was added and spray drying was performed. Then, it was molded into a predetermined shape and fired. At this time, firing was carried out on all the samples in the atmosphere at normal pressure, and the firing temperature was set to 1300 to 1450 ° C. and the holding time was set to 2 hours to obtain the samples of Examples 1 to 6 and Comparative Examples 1 to 3. still,
The average particle diameter is the 50% diameter when the particle size distribution is measured by the laser scattering method. Table 1 shows the blending amount of each raw material powder and the firing temperature.

[0018]

[Table 1]

(2) Evaluation method of physical properties, etc. The ceramic sintered bodies of Examples and Comparative Examples shown in Table 1 were evaluated by the following methods. Content of cordierite and mullite: X-ray diffraction measurement was performed on the sintered body, and the amount of mullite was calculated from a calibration curve previously prepared from the peak intensity of the mullite crystal (110) plane and the peak intensity of the cordierite crystal (110) plane. It was calculated. For the calibration curve, sinters obtained by adding 0, 5, 10% by volume of mullite to cordierite were prepared, and these sinters were measured by X-ray diffraction.
It was determined from the ratio of the peak intensity of the mullite crystal (110) plane to the peak intensity of the cordierite crystal (110) plane. Sintered body density; evaluated by the Archimedes method specified in JIS R 1634, and the numerical value is JIS Z 8401.
Rounded to two decimal places. Peak intensity ratio: The sintered body was subjected to X-ray diffraction measurement, and the obtained cordierite crystal (110) plane and mullite crystal (1
10) The peak intensity of the plane was calculated by the above calculation formula (1) (see the X-ray diffraction chart of the ceramic sintered body of Example 3 in FIG. 2). The Young's modulus was measured at room temperature by the ultrasonic pulse method defined by JIS R 1602. Average particle size of cordierite particles in the sintered body; SE is obtained by mirror-polishing the sintered body and performing thermal etching.
M (scanning electron microscope) observation was performed and calculated from the SEM photograph by the intercept method. The average particle size of the cordierite particles of each of the examples and comparative examples in Table 1 was 1.8 μm. Specific stiffness: Young's modulus value was divided by density. Thermal expansion coefficient: Evaluation was performed using a laser interference method defined in JIS R 3251 and calculated as an average thermal expansion coefficient of 20 to 25 ° C. Table 2 shows the amounts of cordierite and mullite contained in each ceramic sintered body of Examples and Comparative Examples, and the density, peak strength ratio, Young's modulus, specific rigidity and thermal expansion coefficient of the sintered body. In Table 2, "volume%" indicates the volume% of each of the cordierite and mullite produced by the reaction of the raw material powder when the total volume is 100 volume%. Further, FIG. 1 shows the relationship between the amount of mullite, the coefficient of thermal expansion, and the specific rigidity of Examples 1 to 6 and Comparative Examples 1 and 2.

[0020]

[Table 2]

(3) Effects of Examples As shown in FIG. 1 and Table 1, Comparative Example 1 (ceramics sintered body consisting only of cordierite containing no mullite) and Comparative Example 2 (87% by volume of cordierite) And mullite 13% by volume) have large thermal expansion coefficients of 0.22 ppm / K and 0.48 ppm / K, respectively. In particular, Comparative Example 2 has a very large coefficient of thermal expansion.
The specific rigidity is 54.2 GPa / g / cm ³ , 5 respectively.
It was 6.6 GPa / g / cm ³ , and it can be seen that Comparative Example 1 has a small specific rigidity. Furthermore, according to Table 1, Comparative Example 3
(Comprising 97% by volume of cordierite and 3% by volume of mullite and having a small density of 2.37 g / cm ³ ) is
Although the coefficient of thermal expansion is as small as 0.06 ppm / K, the specific rigidity is very small as 50.6 GPa / g / cm ³ .

On the other hand, as shown in FIG. 1 and Table 1, Examples 1 to 6 have a coefficient of thermal expansion of −0.03 to 0.1.
6 ppm / K, both of which are small. Among them, Examples 1 to 5 are particularly small, -0.03 to 0.10 ppm / K, which is about 1/10 to 1/3 of that of Comparative Example 1. small. In particular, Examples 1 and 3 have a thermal expansion coefficient of about 1/10, which is extremely small as compared with Comparative Example 1. That is, in Examples 1 and 3 in which cordierite contained a small amount of mullite of 1% by volume or 3% by volume, respectively, the coefficient of thermal expansion was from 0.22 ppm / K of Comparative Example 1 to 0.02 ppm / K.
Suddenly becomes smaller. Further, in Examples 1 to 6, the specific rigidity was 55.2 G to 56.5 GPa / g / cm ³ and Comparative Example 1
Big compared to. From the above, it can be seen that Examples 1 to 6 have excellent thermal expansion coefficient and specific rigidity, and are extremely well balanced. Further, the coefficient of thermal expansion has a substantially curved downward convex shape as shown in FIG. 1, which shows an unexpected and unexpected behavior.

In each of the above-mentioned embodiments, the coefficient of thermal expansion is small and the specific rigidity is large as compared with the conventionally known cordierite, and there are effects that cannot be predicted from the prior art. This effect is considered to be obtained for the following reasons. That is, the cordierite generation region is very narrow, and a slight composition shift causes the second phase to precipitate.
Therefore, by slightly shifting the composition of the cordierite sintered body toward the mullite formation side, precipitation of a phase having a small Young's modulus and a large coefficient of thermal expansion is suppressed, and a sintered material having a small coefficient of thermal expansion and a large Young's modulus is obtained. The body can be manufactured stably. Even if a cordierite single phase is used, a glass phase or the like is generated, the cordierite single phase cannot be stably obtained, and the thermal expansion coefficient becomes large.

(4) Application Example of Ceramics Sintered Body of Example Since the ceramics sintered bodies of the present invention and other inventions are mainly composed of cordierite having a small thermal expansion coefficient, The overall coefficient of thermal expansion is extremely small, and there are few dimensional changes and shape changes due to temperature changes. Moreover, by firing the material for forming the above-mentioned ceramic sintered body, it is possible to obtain a ceramic sintered body having a high density and a high specific rigidity. Therefore, by using the above-mentioned ceramic sintered body, there is little dimensional change or shape change due to temperature change,
Further, it is possible to obtain a ceramic component having high rigidity, for example, a ceramic component which can be suitably used for a semiconductor manufacturing device, a precision control machine, an optical device, a catalyst carrier and the like.

The use of the ceramic member made of the above-mentioned ceramic sintered body will be described below. First, a vacuum chuck using a ceramics sintered body having the configuration of the above embodiment and a semiconductor manufacturing apparatus using the vacuum chuck will be described. As shown in FIG. 3, the vacuum chuck 1 is a disk-shaped suction plate that sucks and holds the semiconductor wafer 3 by a suction force due to reduced pressure. The vacuum chuck 1 includes a disk-shaped substrate 11 and suction holes 111 that penetrate the substrate 11 in the plate thickness direction (for decompression).
And a large number of protrusions 112 protruding to the suction surface K side of the substrate 11 (semiconductor wafer 3 side), and an annular seal portion 113 provided upright so as to surround the periphery of the protrusions 112.

Although not shown, the above-mentioned vacuum chuck 1 is used by being mounted on a known polishing machine which constitutes a part of a semiconductor manufacturing apparatus. This polishing machine is a CMP apparatus for chemical-mechanical polishing (CMP) the semiconductor wafer 3, and mainly includes a rotatably arranged platen and a platen arranged above the platen, and vacuum-fixes the semiconductor wafer 3 to fix it. And a polishing head capable of Then, in this polishing machine, the vacuum chuck 1 is attached to the polishing head and the vacuum pump is operated to reduce the pressure in the space inside the polishing head, whereby the surface of the vacuum chuck 1 on which the protrusion 112 is formed, The space formed by the seal portion 113 and the semiconductor wafer 3 is depressurized through the suction holes 111, and the semiconductor wafer 3 is sucked and fixed to the suction surface K side of the vacuum chuck 1. Next, while the semiconductor wafer 3 is placed between the polishing pad mounted on the platen and the vacuum chuck 1, slurry for CMP is supplied to the surface of the polishing pad,
The surface of the semiconductor wafer 3 is polished by rotating the platen and the polishing head. This vacuum chuck 1 is made of a ceramics sintered body having the above-mentioned properties, has low thermal expansion and high rigidity, and has little dimensional change or shape change due to temperature change, and therefore has a high dimensional accuracy. Can be manufactured.

Next, as another application example, an electrostatic chuck using a ceramics sintered body having the structure of the above embodiment will be described. As shown in FIG. 4, the electrostatic chuck 2
1 has a disk-shaped member made of the above-mentioned ceramics sintered body as a base body 211, and one surface of the electrostatic chuck 21 (the back surface in the lower part of FIG. 1) has a metal disk-shaped member with a bonding layer 4 interposed therebetween. The base plate 22 of is joined. The electrostatic chuck 21 to which the base plate 22 is joined is referred to as an electrostatic chuck device 2.

Inside the electrostatic chuck 21 (hence the inside of the base body 211), a pair of internal electrodes 2111 and 211 are provided.
2 is embedded, and the other surface of the electrostatic chuck 21 (upper surface in the figure) is, for example, an adsorption surface (chuck surface) 2113 for adsorbing and fixing the semiconductor wafer 3. still,
A through hole (not shown) is provided through the electrostatic chuck 21 and the base plate 22 in the vertical direction in FIG. 4, and He gas for cooling or the like is supplied to the adsorption surface 2113 side through the through hole. Good. In the electrostatic chuck 21, when used, a DC voltage of about ± 1000 V is applied to the chuck to generate a Coulomb force for adsorbing the semiconductor wafer 3, and the adsorbing force adsorbs and fixes the semiconductor wafer 3. The electrostatic chuck 21 is made of a ceramics sintered body having the above-mentioned properties, and since the dimensional change and the shape change due to the temperature change are small, the semiconductor wafer 3 having high dimensional accuracy can be manufactured.

[0029]

The ceramic sintered body of the present invention has a coefficient of thermal expansion smaller than that of conventional cordierite ceramics, and has a large specific rigidity and an excellent performance balance between the two. Therefore, it can be suitably used especially for precision machine parts and optical equipment parts that require low thermal expansion and high specific rigidity, or parts that require high thermal shock resistance. Further, according to the manufacturing method of the present invention, it is possible to easily manufacture a ceramic sintered body having a small coefficient of thermal expansion and a large specific rigidity.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of mullite contained, a coefficient of thermal expansion, and a specific rigidity value.

2 is an X-ray diffraction chart of a ceramics sintered body of Example 3. FIG.

FIG. 3 is a partially cutaway perspective view showing a semiconductor wafer and a vacuum chuck made of a ceramics sintered body.

FIG. 4 is a partially cutaway perspective view showing an electrostatic chuck device including an electrostatic chuck and a base plate.

[Explanation of symbols]

1; vacuum chuck, 3; semiconductor wafer, 11; substrate, 1
11: suction hole, K; suction surface, 112; protrusion, 113;
Sealing part, 21; electrostatic chuck, 211; substrate, 4; bonding layer, 22; base plate, 2; electrostatic chuck device, 211
1, 2112; a pair of internal electrodes, 2113; adsorption surface.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ken Mitsuoka             14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Japan special             Within Toyo Co., Ltd. (72) Inventor Kazuhiro Urashima             14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Japan special             Within Toyo Co., Ltd. F-term (reference) 4G030 AA07 AA36 AA37 BA18 BA20                       BA24 CA01 GA09 HA04 HA18                 5F004 BB21 BB22 BB29                 5F031 CA02 HA02 HA03 HA08 HA13                       HA16 HA39 MA22 PA11

Claims (9)

[Claims] 1. When the total content of cordierite and mullite is 100% by volume, it is composed of 90 to 99.8% by volume of cordierite and 0.2 to 10% by volume of mullite, and has a density of 2.48 g / cm ³ or more, a ceramics sintered body characterized by the above. 2. A peak intensity value of the (110) plane of a cordierite crystal composed of cordierite and mullite, which is measured by an X-ray diffraction method is defined as B, and a peak intensity of the (110) plane of the mullite crystal is defined as B. When the value is A, the value of C represented by the following formula (1) is 0.2 to 20, and the density is 2.48 g / cm ³ or more. C = (A / B) × 100 (1) 3. The ceramic sintered body according to claim 1, wherein the cordierite crystals have an average particle size of 2 μm or less. 4. The coefficient of thermal expansion measured at 20 to 25 ° C. is −
The ceramic sintered body according to any one of claims 1 to 3, which has a value of 0.2 to 0.2 ppm / K and a value obtained by dividing Young's modulus by density is 54.3 GPa / g / cm ³ or more. . 5. A member for a semiconductor manufacturing apparatus.
The ceramic sintered body according to any one of items 1 to 4. 6. The ceramic sintered body according to claim 1, which is a member for a vacuum chuck. 7. The ceramic sintered body according to claim 1, which is a member for an electrostatic chuck. 8. (1) Mg oxide powder and heated M
At least one of Mg compound powders that become g oxide, Al oxide powder, and A that becomes Al oxide when heated.
a mixture of at least one of the 1 compound powder and at least one of the Si oxide powder and the Si compound powder which is heated to become the Si oxide, or (2) Mg,
A mixture of two or more of Al and Si composite oxide powders, or (3) at least one of the above metal oxide powders and each metal compound powders and the above metal composite oxide powders When at least one kind is mixed and the total content of cordierite and mullite is 100% by volume, cordierite is 90 to 99.8% by volume and mullite is 0.2 to 10% by volume. A method for producing a ceramics sintered body, comprising: 9. The coefficient of thermal expansion of the present ceramics sintered body measured at 20 to 25 ° C. is −0.2 to 0.2 ppm / K, and the value obtained by dividing Young's modulus by the density is 54.3 GPa /
The method for producing a ceramics sintered body according to claim 8, wherein the method is g / cm ³ or more.