阅读说明：本技术 复合烧结体、半导体制造装置部件及复合烧结体的制造方法 (Composite sintered body, semiconductor manufacturing apparatus component, and method for manufacturing composite sintered body ) 是由 永井明日美 井上胜弘 胜田祐司 于 2019-02-18 设计创作，主要内容包括：复合烧结体的制造方法具备：将混合Al<Sub>2</Sub>O<Sub>3</Sub>、SiC以及MgO而得到的混合粉末成型为规定形状的成型体的工序(步骤S11)、以及将该成型体烧成而生成复合烧结体的工序(步骤S12)。并且,步骤S11中,SiC相对于混合粉末的比例为4.0重量％以上且13.0重量％以下。另外,步骤S11中的Al<Sub>2</Sub>O<Sub>3</Sub>的纯度为99.9％以上。由此,能够抑制Al<Sub>2</Sub>O<Sub>3</Sub>的异常粒生长,并且,能够很好地制造具有高相对介电常数及耐电压、以及低tanδ的复合烧结体。(A method for producing a composite sintered body, comprising: mixing Al 2 O 3 A step of molding a mixed powder of SiC and MgO into a molded body having a predetermined shape (step S11), and a step of firing the molded body to produce a composite sintered body (step S12). In step S11, the ratio of SiC to the mixed powder is 4.0 wt% or more and 13.0 wt% or less. In addition, Al in step S11 2 O 3 The purity of (A) is 99.9% or more. This can suppress Al 2 O 3 The composite sintered body of (2) can be produced satisfactorily, and the composite sintered body has a high relative permittivity and withstand voltage and a low tan.)

1. A composite sintered body, wherein,

the disclosed device is provided with: alumina, silicon carbide and magnesium-aluminum composite oxide,

the magnesium-aluminum composite oxide has a spinel-type crystal structure,

the silicon carbide comprises a beta-type silicon carbide,

the grain size of the silicon carbide is 0.7 μm or more in D50,

the ratio of carbon in the silicon carbide to the composite sintered body is 1.0 wt% or more and 4.0 wt% or less.

2. The composite sintered body according to claim 1,

the ratio of magnesium in the magnesium-aluminum composite oxide to the composite sintered body is 0.01 wt% or more and 1.0 wt% or less.

3. The composite sintered body according to claim 1 or 2,

the closed porosity is 1.0% or less.

4. The composite sintered body according to any one of claims 1 to 3,

the particle diameter of the silicon carbide is 0.3 μm or more in D10.

5. The composite sintered body according to any one of claims 1 to 4,

the particle diameter of the silicon carbide is 1.5 μm or more in terms of D90.

6. The composite sintered body according to any one of claims 1 to 5,

the content of beta-type silicon carbide in the silicon carbide is more than 50%.

7. The composite sintered body according to any one of claims 1 to 6,

the sintered particle size of the alumina has an average particle size of 2 μm or more.

8. The composite sintered body according to any one of claims 1 to 7,

the withstand voltage is more than 25 kV/mm.

9. The composite sintered body according to any one of claims 1 to 8,

the dielectric loss tangent at a frequency of 40Hz and a frequency of 1MHz was 1.0 × 10^－2The following.

10. The composite sintered body according to any one of claims 1 to 9,

a relative dielectric constant of 12 or more at a frequency of 40Hz and a frequency of 1 MHz.

11. The composite sintered body according to any one of claims 1 to 10,

volume resistivity at 25 ℃ is 1.0 × 10¹⁵Omega cm or more.

12. The composite sintered body according to any one of claims 1 to 11,

the 4-point bending strength is 450MPa or more.

13. The composite sintered body according to any one of claims 1 to 12,

the open porosity is 0.1% or less.

14. A semiconductor manufacturing apparatus component used in a semiconductor manufacturing apparatus, wherein,

the semiconductor manufacturing apparatus component is manufactured using the composite sintered body according to any one of claims 1 to 13.

15. The semiconductor manufacturing apparatus component of claim 14,

the semiconductor manufacturing apparatus component is an electrostatic chuck,

the electrostatic chuck is provided with:

a chuck body produced using the composite sintered body; and

and an internal electrode disposed inside the chuck body.

16. A method for producing a composite sintered body, comprising:

a) a step of molding a mixed powder obtained by mixing alumina, silicon carbide, and magnesium oxide into a molded body having a predetermined shape; and

b) a step of firing the molded article to produce a composite sintered body,

the silicon carbide comprises a beta-type silicon carbide,

in the step a), the ratio of the silicon carbide in the mixed powder is 4.0 wt% or more and 13.0 wt% or less,

the purity of the alumina in the step a) is 99.9% or more.

17. The method for producing a composite sintered body according to claim 16,

in the step a), the ratio of the magnesium oxide in the mixed powder is 0.05 wt% or more and 1.0 wt% or less.

18. The method for producing a composite sintered body according to claim 16 or 17,

the raw material particle diameter of the silicon carbide in the step a) is 0.3 μm or more in D10, 1 μm or more in D50, and 2 μm or more in D90.

19. The method for manufacturing a composite sintered body according to any one of claims 16 to 18,

the sintered particle size of the alumina after the step b) is 2 μm or more in average particle size.

Technical Field

The invention relates to a composite sintered body, a semiconductor manufacturing apparatus component, and a method for manufacturing the composite sintered body.

Background

Conventionally, in manufacturing apparatuses for semiconductor substrates and the like, there have been used susceptors such as an electrostatic chuck for holding a semiconductor substrate by attracting the semiconductor substrate by coulomb force or johnson rahbek force, a heater for heating the semiconductor substrate at a high temperature, and an electrostatic chuck heater formed by combining these. The electrostatic chuck is provided with: the semiconductor device includes a substantially disk-shaped main body portion on which a semiconductor substrate is mounted, and an internal electrode implanted in the main body portion. In the electrostatic chuck, a dc voltage is applied between the internal electrode and the semiconductor substrate, so that a portion between the internal electrode and the semiconductor substrate in the main body portion functions as a dielectric layer, and the semiconductor substrate is attracted to the main body portion.

Japanese patent No. 6032022 (document 1) and japanese patent No. 6103046 (document 2) disclose dielectric materials for electrostatic chucks, which are formed of a composite sintered body in which conductive particles having a small particle size are dispersed in an insulating material. The insulating material may be Al₂O₃For example, SiC is given as an example of the conductive particles. The SiC particles used in the production of the dielectric material in document 1 include 50 to 100% by weight of SiC particles having a particle diameter of 0.05 μm or less. Further, SiC particles used in the production of the dielectric material in document 2 include 67 to 75% by weight of SiC particles having a particle diameter of 0.05 μm or less.

On the other hand, japanese patent No. 5501040 (document 3) discloses a method for producing an alumina sintered body used for an electrostatic chuck or the like, in which Al is used₂O₃And MgF₂The hot-pressing firing of the mixed powder of (1).

In addition, jp 2006-₂O₃A sintered body containing 5 to 35 wt% of SiC particles having an average particle diameter of 0.5 to 2 μm and an Mg content of 0.05 wt% or less in terms of oxide is proposed.

In paragraph 0030 of Japanese patent laid-open publication No. 2000-34174 (document 5), it is proposed to add MgO as a sintering aid to Al₂O₃-a SiC composite material. As described in claim 1, paragraph 0011 and the like, an oxide layer is provided on the surface of the SiC particles, and Al is mixed with the oxide layer₂O₃The particles react to form a liquid phase, promoting sintering.

However, semiconductor manufacturing apparatus parts such as electrostatic chucks are required to have high corrosion resistance against halogen-based etching gases and plasmas of the etching gases. However, in the dielectric materials of documents 1 and 2, SiC having relatively low corrosion resistance has a small particle size, and Al₂O₃Since the particle diameter of (a) is also small, the unevenness of the electrostatic chuck surface becomes remarkable with the corrosion and the falling off of SiC, and the particles further fall off, and there is a possibility that the corrosion amount per unit time becomes large. In addition, Al is present when the semiconductor substrate is adsorbed₂O₃Particles are dislodged from the electrostatic chuck and may also generate particles.

In recent years, in the production of multilayer three-dimensional NAND and the like, a high-power and high-speed etching apparatus is used for microfabrication with a high aspect ratio. The electrostatic chuck used in the etching apparatus is required to have a low RF loss, a high dielectric constant, and a low dielectric breakdown. In addition, in order to suppress heat generation when RF is applied, it is also required that tan (that is, dielectric loss tangent) be low.

On the other hand, in the dielectric material of document 2, the tan at 40Hz is 0.018 to 0.042, the tan at 1MHz is 0.0034 to 0.0062, and the withstand voltage of the dielectric materials of documents 1 and 2 is 16kV/mm or less. The tan of the material is not sufficiently low and there is a possibility of heat generation due to a high frequency (RF) environment. Further, the withstand voltage is not sufficiently high, and when the dielectric material is used for the electrostatic chuck of the etching apparatus, dielectric breakdown may occur. In addition, since the SiC particles are finely and highly dispersed in the dielectric material, the SiC particles are likely to become conductive paths, and the withstand voltage is unlikely to increase. Further, it is presumed that the sintering property of the dielectric material is reduced due to the fine SiC particles, and it is difficult to reduce tan and improve withstand voltage even by the closed pores generated thereby. In order to suppress heat generation of the ceramic at the time of RF application, tan is preferably 0.01 or less, and more preferably 0.005 or less. The withstand voltage is preferably 25kV/mm or more, and more preferably 30kV/mm or more.

In addition, in document 4, it is considered that commercially available easy-to-sinter Al previously added with MgO is used according to the descriptions of paragraph 0019 and table 1, and the like₂O₃Raw materials. The easily sinterable alumina raw material contains a large amount of impurities (for example, several hundred ppm or more) such as sodium (Na), and an amorphous phase derived from the impurities is generated in the grain boundary of the sintered body. In this sintered body, Mg or the like added as a sintering aid also easily enters the amorphous phase, and a compound derived from Mg or the like is amorphized in the grain boundary without forming a crystal structure. The above conclusion can also be determined by the following, that is, described in paragraph 0010 of cited document 4: if the Mg content exceeds 0.05 wt%, Al is contained in₂O₃The grain boundary and the like of (2) form a low-melting-point magnesium work, and the high-temperature strength of the sintered body is lowered. Therefore, for Al₂O₃Inhibition of abnormal grain growth (i.e., inhibition of coarsening of sintered grain size) is limited.

In the same manner as in document 5, Mg or the like added as a sintering aid is incorporated into the surface oxide layer of SiC particles and Al₂O₃A liquid phase (i.e., an amorphous phase) formed by the reaction of the particles. Therefore, compounds derived from Mg and the like are amorphized at the grain boundaries of the sintered body without forming a crystalline structure. Therefore, for Al₂O₃Inhibition of abnormal grain growth is limited.

Disclosure of Invention

The present invention relates to a composite sintered body, and an object thereof is to provide a composite sintered body which suppresses abnormal grain growth of alumina, has a high relative permittivity and withstand voltage, and has a low tan.

A composite sintered body according to a preferred embodiment of the present invention includes: alumina, silicon carbide, and a magnesium-aluminum composite oxide having a spinel-type crystal structure. The silicon carbide comprises beta-type silicon carbide. The particle diameter of the silicon carbide is 0.7 μm or more in D50. The ratio of carbon in the silicon carbide to the composite sintered body is 1.0 wt% or more and 4.0 wt% or less. According to the present invention, a composite sintered body can be provided which can suppress abnormal grain growth of alumina, has a high relative permittivity and withstand voltage, and has a low tan.

Preferably, the ratio of magnesium in the magnesium-aluminum composite oxide to the composite sintered body is 0.01 wt% or more and 1.0 wt% or less.

Preferably, the composite sintered body has a closed porosity of 1.0% or less.

Preferably, the particle size of the silicon carbide is 0.3 μm or more in D10.

Preferably, the particle size of the silicon carbide is 1.5 μm or more in D90.

Preferably, the content of β -type silicon carbide in the silicon carbide is greater than 50%.

Preferably, the sintered particle size of the alumina has an average particle size of 2 μm or more.

Preferably, the composite sintered body has a withstand voltage of 25kV/mm or more.

Preferably, the dielectric loss tangent of the composite sintered body at a frequency of 40Hz and a frequency of 1MHz is 1.0 × 10^－2The following.

Preferably, the composite sintered body has a relative dielectric constant of 12 or more at a frequency of 40Hz and a frequency of 1 MHz.

Preferably, the volume electricity of the composite sintered body is 25 DEG CResistivity of 1.0 × 10¹⁵Omega cm or more.

Preferably, the composite sintered body has a 4-point bending strength of 450MPa or more.

Preferably, the composite sintered body has an open porosity of 0.1% or less.

The invention also relates to a semiconductor manufacturing apparatus component. A semiconductor manufacturing apparatus member according to a preferred embodiment of the present invention is manufactured using the above-described composite sintered body. According to the present invention, a semiconductor manufacturing apparatus component can be provided which can suppress abnormal grain growth of alumina, has a high relative permittivity and withstand voltage, and has a low tan.

The invention also relates to a method for producing the composite sintered body. A method for producing a composite sintered body according to a preferred embodiment of the present invention includes: a) a step of molding a mixed powder obtained by mixing alumina, silicon carbide, and magnesium oxide into a molded body having a predetermined shape; and b) firing the molded article to produce a composite sintered body. The silicon carbide comprises beta-type silicon carbide. In the step a), the ratio of the silicon carbide in the mixed powder is 4.0 wt% or more and 13.0 wt% or less. The purity of the alumina in the step a) is 99.9% or more. According to the present invention, a composite sintered body can be provided which can suppress abnormal grain growth of alumina, has a high relative permittivity and withstand voltage, and has a low tan.

Preferably, in the step a), the ratio of the magnesium oxide in the mixed powder is 0.05 wt% or more and 1.0 wt% or less.

Preferably, the raw material particle size of the silicon carbide in the step a) is 0.3 μm or more in D10, 1 μm or more in D50, and 2 μm or more in D90.

Preferably, the sintered particle size of the alumina after the step b) is 2 μm or more in average.

Drawings

Fig. 1 is a cross-sectional view of an electrostatic chuck.

Fig. 2 is a diagram showing a manufacturing flow of the chuck body.

Fig. 3 is an SEM image of the polished surface of the composite sintered body.

Fig. 4 is an SEM image of the polished surface of the composite sintered body.

Fig. 5 is an X-ray diffraction pattern of the composite sintered body.

Fig. 6 is an enlarged view of an X-ray diffraction pattern of the composite sintered body.

Fig. 7 is an element map image of the composite sintered body.

Fig. 8 is a diagram showing the results of element mapping of the composite sintered body.

Fig. 9 is a diagram showing the results of element mapping of the composite sintered body.

Fig. 10 is a diagram showing the results of element mapping of the composite sintered body.

Detailed Description

Fig. 1 is a sectional view of an electrostatic chuck 1 according to an embodiment of the present invention. The electrostatic chuck 1 is a semiconductor manufacturing apparatus component used in a semiconductor manufacturing apparatus. The electrostatic chuck 1 holds a substantially disk-shaped semiconductor substrate 9 (hereinafter, simply referred to as "substrate 9") by being attracted to and held by coulomb force or johnson rabek force.

The electrostatic chuck 1 includes: chuck section 21, and base section 22. The chuck section 21 is a substantially disk-shaped member. Chuck section 21 is mounted on base section 22. The chuck unit 21 includes: a chuck body 23, and an internal electrode 24. The chuck body 23 is a substantially disk-shaped member formed of a composite sintered body. The substrate 9 is placed on the upper surface of the chuck body 23. The internal electrode 24 is an electrode disposed inside the chuck body 23. In the electrostatic chuck 1, a dc voltage is applied between the internal electrode 24 and the substrate 9, so that a portion between the internal electrode 24 and the substrate 9 in the chuck main body 23 functions as a dielectric layer, and the substrate 9 is attracted to the upper surface of the chuck main body 23. Although not shown, a heater electrode may be provided inside the chuck body 23 on the base portion 22 side.

The chuck body 23 is a composite sintered body, and includes: al (Al)₂O₃(aluminum oxide), SiC (silicon carbide), and Mg-Al composite oxide (magnesium-aluminum composite oxygen) having a spinel-type crystal structureCompound (ii). In the following description, the above-mentioned Mg — Al composite oxide having a spinel-type crystal structure is also simply referred to as "Mg — Al composite oxide". The ratio of C (carbon) to the entire composite sintered body (i.e., the ratio of C in SiC to the composite sintered body) is 1.0 wt% or more and 4.0 wt% or less. Preferably, the ratio of C in the composite sintered body is 1.1 wt% or more and 3.8 wt% or less. The proportion of Mg in the Mg — Al composite oxide (i.e., Mg contained in the Mg — Al composite oxide) to the entire composite sintered body is preferably 0.01 wt% or more and 1.0 wt% or less. More preferably, the proportion of Mg in the composite sintered body is 0.01 wt% or more and 0.7 wt% or less. In the chuck body 23, particles of SiC are dispersed in Al₂O₃The interior of the particles, the grain boundaries, and the triple points of the grain boundaries, the particles of the Mg — Al composite oxide are present in the form of particles and dispersed in the composite sintered body.

The particle diameter (i.e., particle diameter) of the SiC particles dispersed in the composite sintered body is preferably 0.3 μm or more in D10. Further, D50 is preferably 0.7 μm or more. D90 is preferably 1.5 μm or more. D10, D50, and D90 are particle diameters at which the cumulative volume percentages in the volume particle size distribution of SiC particles are 10 volume%, 50 volume%, and 90 volume%, respectively. With respect to Al in the chuck body 23₂O₃The sintered particle size of (2) is preferably 2 μm or more in average particle size. The chuck body 23 preferably has a closed porosity of 1.0% or less.

The withstand voltage of the chuck main body 23 is preferably 25kV/mm or more, and the tan (i.e., the dielectric loss tangent) of the chuck main body 23 at a frequency of 40Hz and a frequency of 1MHz is preferably 1.0 × 10^－2More preferably, the tan is 1.0 × 10 in the range of 40Hz to 1MHz^－2The relative dielectric constant of the chuck body 23 at a frequency of 40Hz and a frequency of 1MHz is preferably 12 or more, more preferably 12 or more in a range of 40Hz to 1MHz, and the volume resistivity of the chuck body 23 at a temperature of 25 ℃ is preferably 1.0 × 10¹⁵Omega cm or more. The 4-point bending strength of the chuck body 23 is preferably 450MPa or more.

Next, referring to FIG. 2, the chuck body 23 is manufacturedThe manufacturing method is explained. In manufacturing the chuck body 23, first, Al is mixed₂O₃The mixed powder of SiC and MgO (magnesium oxide) is molded into a molded body having a predetermined shape (step S11).

For example, in step S11, Al is first mixed₂O₃SiC and MgO powders are wet-mixed in an organic solvent to prepare a slurry. Then, the slurry is dried to prepare a mixed powder (i.e., a mixed powder), and the mixed powder is molded into the molded article. The solvent used in the wet mixing may be, for example, ion-exchanged water. In addition, Al₂O₃The powders of SiC and MgO may be mixed by dry mixing instead of wet mixing.

The mixed powder is filled in, for example, a hot press mold, and molded into a molded body having a predetermined shape. When the shape of the molded article is a plate, the mixed powder may be filled in a die for uniaxial press molding or the like to be molded. The molded article may be formed by various other methods as long as the shape can be maintained. Further, the slurry can be poured into a mold in a fluid state as in the case of the slurry described above, and then the solvent component can be removed to form a molded article having a predetermined shape.

In step S11, the ratio of SiC in the mixed powder is 4.0 wt% or more and 13.0 wt% or less. Preferably, the ratio of SiC in the mixed powder in step S11 is 4.0 wt% or more and 10.0 wt% or less. The proportion of MgO in the mixed powder is preferably 0.025 wt% or more and 1.0 wt% or less, and more preferably 0.05 wt% or more and 0.3 wt% or less. Al (Al)₂O₃The purity of SiC and MgO is preferably 99% or more, and more preferably 99.9% or more.

Since the SiC used in step S11 is preferably β -SiC (i.e., a crystal form of β type SiC), tan can be reduced as compared with the case of using α -SiC (i.e., a crystal form of α type SiC), the particle size (i.e., the raw material particle size) of SiC in step S11 is preferably 0.3 μm or more in D10, 1 μm or more in D50, and 2 μm or more in D90The results obtained by the laser diffraction method and the particle size distribution measuring apparatus. When the particle diameter of the SiC raw material is within the above range, the SiC raw material is dispersed in Al as a dispersion when the SiC raw material is mixed or pulverized to form a sintered body₂O₃The particle size of the SiC particles (observed by SEM (scanning electron microscope)) in (1) is easy to obtain, wherein D10 is 0.3 μm or more, D50 is 0.7 μm or more, and D90 is 1.5 μm or more. The particle size distribution of the SiC starting material was measured by laser diffraction, and as a result, D10 was 0.8. mu.m, D50 was 2.5 μm, and D90 was 5.7. mu.m.

After the molded body is obtained in step S11, the molded body is fired to produce a composite sintered body, i.e., the chuck body 23 (step S12). In the case of the hot pressing method, the molded body is placed in a hot pressing mold and heated and pressed to obtain a composite sintered body. In the hot press method, the molded article is fired in, for example, a vacuum atmosphere or a non-oxidizing atmosphere. The heating temperature, pressing pressure and firing time at the time of hot pressing can be determined appropriately. The maximum temperature of the heating temperature at the time of hot pressing is preferably 1650 ℃ or more and 1725 ℃ or less. By setting the maximum temperature to the above range, it is possible to sinter SiC particles with each other, thereby significantly changing the particle size distribution and avoiding the possibility of conversion of β -SiC to α -SiC.

The electrode material may be implanted into the molded body at the same time as the step S11, and the electrode material may be fired together with the molded body at the step S12, thereby generating the internal electrode 24 inside the chuck body 23. Alternatively, the inner electrode 24 may be disposed inside the chuck body 23 formed of the 2 composite sintered bodies by sandwiching the inner electrode 24 between the 2 composite sintered bodies generated in steps S11 to S12. The formation and arrangement of the internal electrodes 24 can be performed by various methods.

Next, referring to tables 1 to 6, the composite sintered bodies of experimental examples 1 to 13 of the composite sintered body according to the present invention and comparative examples 1 to 5 for comparison with the composite sintered body will be described. As shown in Table 1, in Experimental examples 1 to 13, Al was used as a raw material₂O₃At least one of the composition ratios of SiC and MgO and the maximum temperature of the firing temperature is different. Experiment ofIn examples 1 to 13, SiC was added to Al₂O₃The ratio of the mixed powder of SiC and MgO was 4.0 wt% or more and 13.0 wt% or less, in experimental examples 1 to 13, β -SiC powder was used as the raw material SiC, and in experimental examples 1 to 13, the ratio of MgO to the mixed powder was 0.05 wt% or more and 1.0 wt% or less.

In comparative example 1, only Al was added₂O₃The raw material does not contain SiC and MgO. In comparative example 2, Al was added₂O₃And SiC as a raw material, wherein MgO is not contained in the raw material. In comparative example 3, Al of low purity (less than 99%) was used₂O₃Powder was used as a raw material in comparative example 4, SiC powder (purity 99% or more) having an average particle size of as small as 0.3 μm was used as a raw material, while SiC as a raw material in comparative example 4 included α -SiC powder and β -SiC powder, SiC α -SiC powder was used as a raw material in comparative example 5, and SiC α powder having an average particle size of 2.9 μm and a purity of 98% or more was used as a raw material in comparative example 5.

< raw material powder >

In Experimental examples 1 to 13, Al is used₂O₃High-purity Al with a purity of 99.99% or more and an average particle diameter of 0.4 to 0.6 μm is used₂O₃And (3) powder. With respect to the high purity Al₂O₃The impurity content in the powder, Si is 40ppm or less, Mg, Na and copper (Cu) are 10ppm or less, respectively, and iron (Fe) is 20ppm or less, in examples 1 to 13, β -SiC powder having a purity of 99.9% or more and an average particle size of 2.5 μm is used, and with respect to the impurity content in the β -SiC powder, Al is 100ppm or less, and Mg and Na are 50ppm or less, respectively, high-purity MgO powder having a purity of 99.9% or more and an average particle size of 1 μm or less is used, and with respect to the impurity content in the MgO powder, Al is 10ppm or less, and Si is 10ppm or less, in comparative examples 1 to 5, conditions which are not described in the above paragraph are the same as in the examples.

< Mixed powder >

The raw material powders were weighed in the weight% shown in table 1, and wet-mixed for 4 hours using a nylon pot with isopropyl alcohol as a solvent. Examples 1 to 4 of the wet mixingIn examples 7 to 9 and comparative examples 1 to 5, alumina ball stones with a diameter of 3mm were used, and nylon balls with a diameter of 20mm and an iron core were used in examples 5 to 6 and 10 to 13. The pebbles used in the mixing are not particularly limited, and for example, when pebbles having a high specific gravity and a high pulverization efficiency are used, the raw material powder (SiC particles in this case) is pulverized, and the particle diameter after wet mixing may be smaller than the raw material particle diameter, so that attention is required. The time for wet mixing is preferably adjusted to be within a range of 4 hours to 20 hours so as to disperse in Al₂O₃The particle diameter of the SiC particles in (b) is in the aforementioned preferable range. The mixed slurry was removed and dried at 110 ℃ in a stream of nitrogen. Then, the dried powder was sieved through a 30-mesh sieve to obtain a mixed powder. The solvent in wet mixing may be, for example, ion-exchanged water. Alternatively, the slurry may be dried by a rotary evaporator and then sieved through a 100-mesh sieve to obtain a mixed powder. Alternatively, a spray dryer or the like may be used to obtain a granulated powder. The mixed powder is subjected to heat treatment at 450 ℃ for 5 hours or more in an atmospheric atmosphere, if necessary, to remove carbon components mixed in the wet mixing.

< molding >

Mixing the above powders at a ratio of 100kgf/cm²The pressure of (3) was uniaxially pressed to prepare a disk-shaped molded article having a diameter of 50mm and a thickness of about 20mm, and the molded article was stored in a graphite mold for firing. The molding pressure is not particularly limited, and the shape may be maintained, and various modifications may be made. The mixed powder may be filled in a hot press mold in an unmolded powder state.

< firing >

The molded article was fired by a hot press method under a vacuum atmosphere. The pressing pressure was 250kgf/cm². The maximum temperature during heating is 1650-1725 ℃, and the holding time at the maximum temperature is 4-8 hours.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

[ Table 6]

< evaluation >

The composite sintered body obtained by the above firing was processed and used for various evaluations, and the evaluations described in tables 2 to 6 were performed.

The open porosity, bulk density and apparent density were measured by the Archimedes method using pure water as a medium, a 3mm × 4mm × 40mm bending bar was used for the measurement, the surface was finished with #800, and the respective raw materials (i.e., Al) mixed at the time of producing the composite sintered body were assumed₂O₃SiC and MgO) were all left in the composite sintered body in the original state, and the theoretical density was calculated based on the theoretical density of each raw material and the amount (wt%) of each raw material used. Calculated Al₂O₃Has a theoretical density of 3.99g/cm³The theoretical density of SiC was 3.22g/cm³The theoretical density of MgO is 3.60g/cm³. The bulk density was divided by the theoretical density and multiplied by 100 to calculate the relative density. Assuming that the theoretical density is equal to the true density, the apparent density is divided by the true density, and the value obtained by subtracting the value from 1 is multiplied by 100 to calculate the closed porosity.

A4-point bending test was performed in accordance with JIS R1601 to calculate the 4-point bending strength. The relative dielectric constant and tan were measured in the air at room temperature by the method in accordance with "JIS C2141" using a test piece having a thickness of 2 mm.

The volume resistivity was measured under a vacuum atmosphere and at room temperature by a method in accordance with "JIS C2141". The test piece had a shape of phi 50 mm. times.1 mm. The diameter of the main electrode is 20 mm. The inner and outer diameters of the guard electrode were 30mm and 40mm, respectively. The diameter of the application electrode was 45 mm. The main electrode, the guard electrode, and the application electrode are formed of Ag (silver). The applied voltage was 500V/mm. The current value 1 minute after the voltage application was read, and the volume resistivity was calculated from the current value.

The withstand voltage is: the instantaneous withstand voltage was measured by applying a DC voltage to a test piece having a thickness of 0.2mm in the atmosphere at room temperature by the method in accordance with "JIS C2141".

The particle size of SiC was determined by SEM observation. Specifically, in an SEM image obtained by observing the polished surface of the composite sintered body at a magnification of 3000 times or more, the major axis of the SiC particles was measured as a particle diameter, and particle diameters corresponding to 10%, 50%, and 90% of all the measurement results (60 points or more) were set as D10, D50, and D90, starting with particles having a small particle diameter. Fig. 3 and 4 are SEM images of the polished surfaces of the composite sintered bodies of experimental example 1 and experimental example 2.

Determination of Al by means of the line intercept method₂O₃The particle size of (1). Specifically, an arbitrary number of line segments are drawn on an SEM image obtained by observing the polished surface of the composite sintered body, and the number n of crystal particles crossed by a line segment of length L is determined. When the end of the line segment is located inside the crystal grains, 1/2 crystal grains are present. The average grain size (i.e., average intercept length) L is a value obtained by dividing the length L of the line segment by n, and the average grain size is a value obtained by multiplying the average grain size L by a coefficient of 1.5.

In an arbitrary number of line segments on the SEM image, one Al₂O₃The maximum length of a line segment L1 on a particle divided by one Al₂O₃The minimum length L2 on the particle was determined to obtain Al₂O₃The particle diameter ratio of (A) is L1/L2.Al₂O₃The higher the uniformity of the distribution of the crystal grain diameter of (3), Al₂O₃The particle diameter ratio of (A) is closer to 1 as compared with L1/L2, and if the uniformity is low, the value is larger as it is farther from 1. As shown in Table 5, if the MgO content of the raw material is low, Al is present₂O₃The particle diameter ratio of (A) to (B) tends to increase in comparison with L1/L2. If Al is present₂O₃When the particle diameter ratio of (3) is close to 1 in the ratio of L1/L2, the uniformity of in-plane corrosion in the chuck main body 23 of the electrostatic chuck 1 is improved, and as a result, the generation of undesirable dust is suppressed. From increasing Al₂O₃From the viewpoint of uniformity of distribution of crystal grain diameters of (1), Al₂O₃The particle diameter ratio of (A) is preferably 8 or less, more preferably 5 or less. Therefore, the ratio of Mg in the Mg — Al composite oxide to the composite sintered body is preferably 0.05 wt% or more, and more preferably 0.075 wt% or more.

The ratio of C in SiC to the entire composite sintered body (C amount) and the ratio of Mg in a Mg — Al composite oxide having a spinel-type crystal structure to the entire composite sintered body (Mg amount) were determined by analytical methods in accordance with "JIS R1616" and "JIS R1649". The amount of C is a value obtained by subtracting the amount of free C from the total amount of C in the composite sintered body. The amount of free C is the impurity carbon in the raw material and the carbon derived from the spherulite used in the mixing, and is 0.03 wt% in example 1. Here, the ratio of the SiC amount to the entire composite sintered body can be derived using the C amount, the atomic weight of carbon (12.01), and the molecular weight of SiC (40.1). For example, in experimental example 1, from table 2, the amount of SiC was derived to be 8.3 wt% since the amount of C was 2.48 wt%, and in experimental example 4, the amount of SiC was derived to be 9.9 wt% since the amount of C was 2.97 wt%. This value may be slightly different from the SiC amount in the raw material composition ratio in table 1, but it is because of the impurity amount of the powder raw material, errors in weighing and analysis, and the like. Although the ratio of the amount of SiC to the entire composite sintered body can be derived by analyzing the amount of C and the amount of Si with respect to the entire composite sintered body, in the scope of the experimental example of this time, if the possibility that a part of SiC reacts to form a reaction phase between Si and the Mg — Al composite oxide is taken into consideration, it is preferable to derive the amount of C by using the amount of C (in the case where SiC reacts, C is discharged to the outside of the system at the time of firing).

In each of examples 1 to 13, the open porosity was 0.1% or less, the closed porosity was 1.0% or less, the 4-point bending strength was 450MPa or more, the relative dielectric constant at a frequency of 300kHz was 12 or more, and the volume resistivity was 1.0 × 10¹⁵Omega cm or more and a withstand voltage of 25kV/mm or more in Experimental examples 1 to 13, tan at frequencies of 40Hz, 300kHz and 1MHz was 1.0 × 10^－2The following. In examples 1 to 13, the particle size of SiC was 0.3 μm or more in D10, 0.7 μm or more in D50, and 1.5 μm or more in D90. Al (Al)₂O₃Has a sintered particle diameter (average particle diameter) of 2 μm or more. The ratio of C in SiC to the entire composite sintered body (C amount) is 1.0 wt% or more and 4.0 wt% or less. The ratio of Mg in the Mg — Al composite oxide to the entire composite sintered body (Mg amount) is 0.01 wt% or more and 1.0 wt% or less.

In comparative examples 1 to 3, the composite sintered body did not contain a Mg-Al composite oxide having a spinel-type crystal structure. In comparative example 1, the relative dielectric constant was less than 12. In comparative example 2, the closed porosity was more than 1.0%. It is considered that the increase in closed porosity in comparative example 2 is due to Al caused by the absence of MgO₂O₃Abnormal grain growth (i.e., excessive grain size, also referred to as coarsening of the grain size). Al in sintered body of comparative example 2₂O₃Has an average particle diameter of 93.3. mu.m. In comparative example 3, the open porosity was more than 0.1%. It is considered that the increase in the open porosity in comparative example 3 is due to Al as a raw material₂O₃The purity of the powder is low so that Mg-Al composite oxide having a spinel-type crystal structure is not substantially formed and Al occurs₂O₃Abnormal grain growth of (2). Al in sintered body of comparative example 3₂O₃Has an average particle diameter of 8.7. mu.m. In comparative example 4, with respect to the particle size of SiC, D10 was less than 0.3 μm, D50 was less than 0.7 μm, and D90 was less than 1.5. mu.m. This is considered to be because the average particle size of SiC of the raw material is as small as 0.3 μm. In comparative example 4, the open porosity was more than 0.1%, and the closed porosity was more than 1.0%. Consider comparative exampleThe reason why the open porosity and closed porosity in 4 were increased was that the average particle diameter of SiC as a raw material was as small as 0.3. mu.m in comparative example 4, the tan at frequencies of 300kHz and 1MHz was higher than 1.0 × 10^－2It is considered that the tan increase in comparative example 4 is because the SiC as the raw material contains α -SiC in comparative example 5, the tan at a frequency of 40Hz is 1.0 × 10^－2Hereinafter, however, the tan at frequencies of 300kHz and 1MHz is higher than 1.0 × 10^－2It is considered that the increase in tan at frequencies of 300kHz and 1MHz in comparative example 5 is due to the fact that the SiC as the raw material is α -SiC.

Experimental examples 14 to 17 in tables 7 and 8 show the relationship between the content of α -SiC in SiC contained in the raw material and the relative permittivity and tan of the composite sintered body. The composite sintered bodies of experimental examples 14 to 17 were produced by the same production method as in experimental examples 1 to 13. In experimental examples 14 to 17, the content of α -SiC was changed. The content of the α -SiC powder was determined by dividing the weight of the α -SiC powder in the SiC powder by the total weight of the SiC powder (i.e., the total of the weight of the α -SiC powder and the weight of the β -SiC powder). The content of β -SiC was also determined in the same manner. The α -SiC powder and the β -SiC powder used in experimental examples 14 to 17 were the same as the α -SiC powder and the β -SiC powder of comparative example 5 and experimental example 1, respectively.

[ Table 7]

[ Table 8]

In examples 14 to 17, the α -SiC contents were 5%, 10%, 25%, 50%, and the β -SiC contents were 95%, 90%, 75%, 50%, respectively, and in examples 14 to 17, the relative permittivity at a frequency of 300kHz was 12 or more, and the tan at frequencies of 40Hz, 300kHz, and 1MHz was 1.0 × 10^－2The following. In Experimental example 17, the relative dielectric constant was 12 or more, but the frequencies were 40Hz, 300kHz andtan higher than 1.0 × 10 at 1MHz^－2In experimental examples 14 to 17, tan at frequencies of 40Hz, 300kHz, and 1MHz increased as the content of β -SiC decreased, and from the viewpoint of decreasing tan, the content of β -SiC in SiC contained in the raw material is preferably more than 50%.

In addition, not described in tables 7 and 8, in experimental examples 14 to 17, the open porosity was 0.1% or less, the closed porosity was 1.0% or less, and the 4-point bending strength was 450MPa or more, and the volume resistivity was 1.0 × 10¹⁵Omega cm or above and the withstand voltage of 25kV/mm or above. The SiC particle diameters are 0.3 μm or more in D10, 0.7 μm or more in D50, and 1.5 μm or more in D90. Al (Al)₂O₃The sintered particle size (average particle size) of (2 μm) or more, the ratio of C in SiC to the entire composite sintered body (C amount) of 1.0 wt% or more and 4.0 wt% or less, and the ratio of Mg in the Mg — Al composite oxide to the entire composite sintered body (Mg amount) of 0.01 wt% or more and 1.0 wt% or less, it was confirmed in experimental examples 14 to 17 that the content of α -SiC in the composite sintered body was substantially the same as the content of α -SiC in SiC contained in the raw material by the Rietveld method, and the Rietveld method was carried out in accordance with JIS K0131 (general X-ray diffraction analysis).

Fig. 5 is an X-ray diffraction pattern obtained by measuring the powder of the composite sintered body of experimental example 2 with an X-ray diffraction apparatus. In this measurement, the composite sintered body as a material was pulverized with a mortar, and the crystal phase was identified with an X-ray diffraction apparatus. The measurement conditions were CuK α, 40kV, 40mA, and 2 θ were 5 to 70 °, and an enclosed tube X-ray diffractometer (D8 ADVANCE, Bruker AXS) was used. The step length was measured at 0.02 °.

In FIG. 5 (Experimental example 2), Al was detected as a constituent phase₂O₃、SiC、MgAl₂O₄(spinel) these 3 phases. Peaks consistent with spinel were detected as extremely small peaks.

FIG. 6 shows a schematic view of a MgAl alloy₂O₄The peaks of fig. 5 are more distinct and the resulting plot is magnified for the low count portion of fig. 5. In FIG. 6, MgAl on the high angle side₂O₄The peak of (a) is buried in other peaks, and it is difficult to determine a clear peak position. Examples of the experiments2, and a general MgAl shown in the lower side of FIG. 6₂O₄Peak position of MgAl₂O₄The peak positions of (a) are shifted. Thus, it is believed that: in the composite sintered body according to the present embodiment, MgAl is used₂O₄Although Mg is contained in the form of a crystal phase of type (i.e., Mg — Al composite oxide having a spinel crystal structure), for example, the ratio of the constituent elements changes and a solid solution reaction occurs due to the coexistence of SiC.

Therefore, the composite sintered body according to the present embodiment is described as a Mg — Al composite oxide as described above with respect to the structure containing Mg. The Mg — Al composite oxide can contain Si by solid solution. It is also estimated that the composite sintered body according to the present embodiment includes: due to MgAl₂O₄The decrease in crystallinity of the compound (b) and the like, and the compound (b) cannot be detected in the X-ray diffraction pattern. In this case, the presence of the Mg — Al composite oxide can be confirmed by elemental mapping by EDS (energy dispersive X-ray spectrometer) or EPMA (electron probe microanalyzer).

Fig. 7 is an EDS elemental map image obtained by applying a magnification of 1000 times to the composite sintered body of experimental example 2. The elements Al, Si, Mg, and O are present in higher concentrations in brighter (closer to white in the drawing) parts. In the distribution diagram of Al in FIG. 7, the gray undertone portion is Al₂O₃In the presence position of (2), Al was not detected in the black island-like scattered portion. When the distribution of Si and O was compared with the island-like portions, Si was detected and O was not detected. Therefore, it was confirmed that the island-like portions correspond to SiC particles, and SiC is dispersed in Al in a granular form₂O₃The situation in (1).

In the Mg distribution diagram of fig. 7, the area surrounded by the circles of the solid line and the broken line is the area where Mg exists. On the other hand, in the Al, Si, and O distribution diagrams, the region surrounded by the circle of the solid line overlaps with the region surrounded by the circle of the solid line in the Mg distribution diagram. In the region surrounded by the solid line circle, Al and O are present in the Mg-present portion, and almost no Si is present. Therefore, a Mg — Al composite oxide exists in this portion. Similarly, in the region surrounded by the dashed circle in the Mg distribution diagram, the Mg — Al composite oxide is also present in the portion where Mg is present.

Fig. 8 to 10 are EPMA elemental map images obtained by applying the composite sintered body of experimental example 2 at a magnification of 3000 times. The region surrounded by the circle of reference numeral 81 in fig. 8 is a region where Al exists, and the region surrounded by the circle of reference numeral 82 in fig. 9 is a region where Mg exists. In fig. 10, the region surrounded by the circle indicated by reference numeral 83 is a region in which O (oxygen) is present. Therefore, the Mg — Al composite oxide exists in the overlapping region of the region 81, the region 82, and the region 83.

Note that the EPMA element map image is classified into red, orange, yellow green, cyan, and blue according to the density, and color-labeled, where red indicates the highest density, blue indicates the lowest density, and black indicates zero. However, since fig. 8 to 10 are displayed in a single color, the original colors of fig. 8 to 10 will be described below. In Al in fig. 8, the ground color is yellow, and island-like portions are green to cyan. In Mg in fig. 9, the ground color is blue, and dotted portions are cyan, and in O in fig. 10, the ground color is orange, and island portions are green to cyan.

As described above, the composite sintered body includes: al (Al)₂O₃The SiC comprises β -SiC, wherein D50 is 0.7 [ mu ] m or more with respect to the particle diameter of SiC in the composite sintered body, and the proportion of C in SiC to the composite sintered body is 1.0 wt% or more and 4.0 wt% or less, whereby the Mg-Al composite oxide having a spinel crystal structure is dispersed in Al with high uniformity₂O₃As a result, Al can be suppressed₂O₃Abnormal grain growth of (2). Further, a composite sintered body having a high relative permittivity and withstand voltage and a low tan can be provided.

Specifically, the relative dielectric constant of the composite sintered body at a frequency of 40Hz and a frequency of 1MHz is preferably 12 or more. This can improve the insulation properties of the composite sintered body. In addition, when the composite sintered body is used in the electrostatic chuck 1, the attraction force of the substrate 9 can be increased. The relative permittivity is more preferably 13 or more, and still more preferably 14 or more. The relative permittivity is more preferably 12 or more (more preferably 13 or more, and even more preferably 14 or more) in the range of the frequency of 40Hz or more and 1MHz or less.

The withstand voltage of the composite sintered body is preferably 25kV/mm or more. Thus, dielectric breakdown of the composite sintered body can be prevented or suppressed satisfactorily. The withstand voltage is more preferably 30kV/mm or more, and still more preferably 50kV/mm or more.

The tan of the composite sintered body at a frequency of 40Hz and a frequency of 1MHz is preferably 1.0 × 10^－2As a result, the dielectric loss of the composite sintered body when an alternating current is applied can be favorably suppressed, and the temperature rise of the composite sintered body can be suppressed, and the tan is more preferably 5.0 × 10^－3Hereinafter, more preferably 3.0 × 10^－3In addition, the tan is more preferably 1.0 × 10 in the range of the frequency of 40Hz or more and 1MHz or less^－2Hereinafter (more preferably 5.0 × 10)^－3Hereinafter, more preferably 3.0 × 10^－3Below). The value of tan tends to depend on the frequency, and the lower the measurement frequency, the lower the value of tan, even in the measurement using the same sample.

The volume resistivity of the composite sintered body at a temperature of 25 ℃ is preferably 1.0 × 10¹⁵Omega cm or more, thereby preventing or suppressing leakage of current through the composite sintered body, and the volume resistivity is more preferably 5.0 × 10¹⁵Omega cm or more, more preferably 1.0 × 10¹⁶Omega cm or more.

The closed porosity of the composite sintered body is preferably 1.0% or less. This can prevent or suppress leakage of current through the composite sintered body. The closed porosity is more preferably 0.7% or less, and still more preferably 0.5% or less.

The 4-point bending strength of the composite sintered body is preferably 450MPa or more. This can prevent or suppress breakage of the composite sintered body. The 4-point bending strength is more preferably 470MPa or more, and still more preferably 490MPa or more.

In the composite sintered body, the grain size of SiC is preferably 0.3 μm or more in D10. Further, D90 is preferably 1.5 μm or more. In this way, the grain diameter ratio of SiC in the composite sintered body is large, and therefore, the SiC can be prevented from falling off due to corrosion. As a result, the surface roughening of the composite sintered body can be suppressed. Further, since SiC particles can be suppressed from becoming conductive paths, the withstand voltage can be increased.

As described above, the content of β -SiC in the composite sintered body is preferably more than 50%. This can further reduce tan of the composite sintered body. More preferably, the content of β -SiC in SiC is substantially 100%. In other words, the crystal form of SiC is β type. This can further reduce tan of the composite sintered body.

Al of step S12₂O₃The sintered particle size of (2) has an average particle size of 2 μm or more. Thus, Al in the composite sintered body₂O₃Has a large grain diameter ratio of (3), so that Al can be suppressed₂O₃The particles are detached from the composite sintered body, and generation of particles can be suppressed.

The composite sintered body containing the Mg-Al oxide having a spinel crystal structure can prevent or suppress an increase in firing temperature due to the inclusion of SiC and Al₂O₃Abnormal grain growth of (2). As a result, the density and uniformity of the particle size distribution of the composite sintered body can be improved, and the yield of the composite sintered body can be improved. As an index of the densification, the open porosity in the composite sintered body is preferably 0.1% or less. In addition, in the composite sintered body, the ratio of Mg in the Mg — Al composite oxide to the composite sintered body is 0.015 wt% or more and 0.5 wt% or less, whereby Al can be further favorably prevented or suppressed₂O₃Abnormal grain growth of (2).

As described above, the composite sintered body has a high relative permittivity and withstand voltage, and a low tan, and is therefore suitable for semiconductor manufacturing apparatus components used in semiconductor manufacturing apparatuses. The composite sintered body is particularly suitable for semiconductor manufacturing equipment parts used in high-output power semiconductor manufacturing equipment such as a high-power etching equipment. The electrostatic chuck 1 is a preferable example of a semiconductor manufacturing apparatus component manufactured using the composite sintered body. The electrostatic chuck 1 includes: the chuck body 23 manufactured using the composite sintered body as described above, and the internal electrode 24 disposed inside the chuck body 23.

The electrostatic chuck 1 can hold the substrate 9 by being attracted to the substrate in a satisfactory manner in a semiconductor manufacturing apparatus. In addition, as described above, Al in the composite sintered body₂O₃And the grain diameter ratio of SiC is large, so that the SiC can be prevented or suppressed from falling off due to corrosion. As a result, the surface roughening of the chuck body 23 can be suppressed. Further, Al can be suppressed when the substrate 9 is adsorbed₂O₃The particles are detached from the chuck body 23, and generation of particles can be suppressed.

As described above, the method for manufacturing a composite sintered body includes: mixing Al₂O₃A step of molding a powder mixture of SiC and MgO into a molded body having a predetermined shape (step S11), and a step of firing the molded body to produce a composite sintered body (step S12). SiC is contained in β -SiC in step S11, the ratio of SiC to the powder mixture is 4.0 wt% or more and 13.0 wt% or less, and Al in step S11 is contained in Al₂O₃The purity of (A) is 99.9% or more. Thus, the Mg-Al composite oxide having a spinel-type crystal structure is dispersed and arranged in Al with high uniformity₂O₃As a result, Al can be suppressed₂O₃Abnormal grain growth of (2). Further, a composite sintered body having a high relative permittivity and withstand voltage and a low tan can be produced favorably.

In step S11, the ratio of MgO to the mixed powder is 0.05 wt% or more and 1.0 wt% or less. This makes it possible to favorably prevent or suppress an increase in firing temperature due to the inclusion of SiC and Al₂O₃Abnormal grain growth of (2).

As described above, regarding the particle size of SiC (i.e., the raw material particle size) in step S11, D10 is 0.3 μm or more, D50 is 1 μm or more, and D90 is 2 μm or more. This makes it possible to produce the composite sintered body having a relatively large SiC particle diameter.

< modification example >

The composite sintered body, the semiconductor manufacturing apparatus component, and the composite sintered body described above can be variously modified in the manufacture thereof.

For example, the ratio of Mg in the Mg — Al composite oxide to the composite sintered body in the composite sintered body may be less than 0.01 wt%, or more than 1.0 wt%, the open porosity of the composite sintered body may be more than 0.1%, the closed porosity may be more than 1.0%, the withstand voltage of the composite sintered body may be less than 25kV/mm, the frequency may be 40Hz or more and 1MHz or less, and the tan of the composite sintered body may be more than 1.0 × 10^－2The relative dielectric constant of the composite sintered body having a frequency of 40Hz or more and 1MHz or less may be less than 12, and the volume resistivity of the composite sintered body at a temperature of 25 ℃ may be less than 1.0 × 10¹⁵Omega cm. The 4-point bending strength of the composite sintered body may be less than 450 MPa.

In the composite sintered body, Al is dispersed₂O₃The particle size of the SiC particles in (1) can be less than 0.3 μm in D10 and less than 1.5 μm in D90. With respect to Al₂O₃The sintered particle size of (2) may be less than 2 μm in average particle size.

In the production of the composite sintered body, the proportion of MgO in step S11 to the mixed powder may be less than 0.025 wt%, or greater than 1.0 wt%. Regarding the particle diameter of SiC (i.e., the raw material particle diameter) in step S11, D10 may be less than 0.3 μm. In addition, D50 can be less than 1 μm and D90 can be less than 2 μm.

The maximum firing temperature in step S12 may be less than 1650 ℃ or higher than 1725 ℃. In step S12, a composite sintered body may be produced by various firing methods other than the hot press method.

The composite sintered body can be used for manufacturing various semiconductor manufacturing apparatus components other than the electrostatic chuck 1. For example, the composite sintered body can be used to manufacture a base used when high frequency is applied to the substrate 9. Further, a member used in an apparatus other than the semiconductor manufacturing apparatus can be formed using the composite sintered body. For example, the composite sintered body can be used for manufacturing a ceramic heater for heating an object.

The configurations in the above embodiments and the modifications may be appropriately combined as long as they are not contradictory to each other.

Industrial applicability

The present invention is applicable to the field related to semiconductor manufacturing apparatuses, for example, the manufacture of an electrostatic chuck for adsorbing and holding a semiconductor substrate by coulomb force or johnson rahbek force.

Description of the symbols

1 Electrostatic chuck

9 semiconductor substrate

23 chuck body

24 internal electrode

S11-S12