JP2016188160A - Corrosion-resistant member and electrostatic chuck member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a corrosion-resistant member capable of increasing the adsorption force of an electrostatic chuck when an electric field is applied and reducing the residual adsorption force of the electrostatic chuck when the application of the electric field is stopped, when used for an electrostatic chuck member; and the electrostatic chuck member.SOLUTION: There are provided a corrosion-resistant member substantially formed of a composite oxide containing samarium, aluminum and oxygen and including a perovskite crystal, in which a segregated part derived from the samarium, existing on at least a main surface of the corrosion-resistant member and having the maximum length of 0.1 mm or more, is 10 or less pieces; and an electrostatic chuck member including the corrosion-resistant member.SELECTED DRAWING: None

Description

  The present invention relates to a corrosion-resistant member and a member for an electrostatic chuck including the same.

  A chuck apparatus is used to hold a wafer in a film forming apparatus such as a CVD apparatus or a sputtering apparatus used in a semiconductor manufacturing process or an etching apparatus for performing fine processing.

  Conventionally, a vacuum chuck method or a mechanical clamp method has been adopted as the chuck device. However, as the semiconductor manufacturing process has been advanced in recent years, an electrostatic chuck method that attracts a semiconductor wafer by electrostatic attraction is used. It has become to. This electrostatic chuck method exhibits superior characteristics compared to the conventional vacuum chuck method and mechanical clamp method in terms of wafer flatness correction and soaking. The operation characteristics of the electrostatic chuck are to generate a large attracting force while applying a voltage to prevent the object to be attracted from dropping, etc. It is desirable that objects can be easily removed.

In addition, a production line for semiconductor devices such as IC, LSI, VLSI, and the like includes a process using a halogen-based corrosive gas such as a fluorine-based corrosive gas or a chlorine-based corrosive gas, and a plasma thereof. In these steps, for example, dry etching, plasma etching, cleaning, and the like are performed on the semiconductor wafer fixed by the electrostatic chuck. For these treatments, fluorine-based gases such as CF ₄ , SF ₆ , HF, NF ₃ , and F ₂ , chlorine-based gases such as Cl ₂ , SiCl ₄ , BCl ₃ , and HCl, and plasmas of these gases are used. Is done. Since these corrosive gases and plasmas are highly corrosive, corrosion of the electrostatic chuck members constituting the electrostatic chuck by these corrosive gases and plasmas has become a problem.

Conventionally, as corrosion-resistant materials used for electrostatic chuck members, there are yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ , hereinafter abbreviated as YAG), and rare earth oxides other than yttrium oxide added to YAG. It is used (for example, see Patent Documents 1 to 3).

JP 2004-315308 A JP 2011-151336 A JP 2012-94826 A

The corrosion-resistant members described in Patent Documents 1 to 3 have high corrosion resistance against halogen-based corrosive gases such as fluorine-based corrosive gases and chlorine-based corrosive gases and their plasmas.
However, as a chuck device in the future semiconductor manufacturing process, the electrostatic chuck is strongly attracted to the wafer when an electric field is applied, and the electrostatic chuck's residual attracting force is weak when the application of the electric field is stopped. It becomes important.

  Therefore, when the present invention is used for a member for an electrostatic chuck, the electrostatic chuck attracting force when applying an electric field is made stronger than before, and the residual chucking of the electrostatic chuck when applying the electric field is stopped. An object of the present invention is to provide a corrosion-resistant member capable of making the force even weaker than before, and an electrostatic chuck member including the same.

As a result of intensive studies in view of the above problems, the present inventors focused on a corrosion-resistant material containing a perovskite crystal, particularly a composite oxide containing samarium and aluminum, as a material having a higher dielectric constant. The inventors have found that the problem can be solved by reducing the segregation portion having a predetermined size derived from samarium existing on the main surface, and have arrived at the present invention.
That is, the present invention is as follows.

[1] A corrosion resistant member substantially composed of a composite oxide containing samarium and aluminum, wherein the composite oxide includes a perovskite crystal and is present on at least one main surface of the corrosion resistant member. A corrosion-resistant member having a segregation part derived from the samarium having a length of 0.1 mm or more and 10 or less.
[2] The corrosion-resistant member according to [1], wherein the relative density of the corrosion-resistant member is 97% or more.
[3] An electrostatic chuck member comprising the corrosion-resistant member according to [1] or [2].

  According to the present invention, when used for an electrostatic chuck member, the electrostatic chuck attracting force when an electric field is applied is increased, and the residual chucking force of the electrostatic chuck is decreased when the application of the electric field is stopped. It is possible to provide a corrosion-resistant member that can be used, and an electrostatic chuck member including the same.

2 is a photograph showing the surface of a corrosion-resistant member of Example 1. 2 is a photograph showing the surface of a corrosion-resistant member of Comparative Example 1.

[Corrosion resistant material]
The corrosion-resistant member of the present invention is substantially composed of a complex oxide containing samarium and aluminum (hereinafter sometimes referred to as “the complex oxide according to the present invention”). By being substantially composed of a composite oxide containing samarium and aluminum, corrosion resistance against various corrosive gases can be exhibited.

  Here, “substantially constituted” allows the inclusion of other elements and compounds (particularly oxides) in addition to the composite oxide according to the present invention to such an extent that the effects of the present invention are not inhibited. Means that. The ratio of the composite oxide according to the present invention in the corrosion-resistant member is, for example, preferably 80% by volume or more, more preferably 90% by volume or more, and further preferably 95% by volume or more. The ratio of the complex oxide according to the present invention can be confirmed by elemental analysis by fluorescent X-ray analysis and quantitative analysis by powder X-ray diffraction.

The composite oxide according to the present invention includes a perovskite crystal. The perovskite crystal is, for example, SmAlO ₃ . Most perovskite type compounds have a structure distorted from cubic lattices such as tetragonal, orthorhombic, and trigonal crystals, so they exhibit ferroelectricity and are used for electrostatic chuck members to which a strong electric field is applied. Was considered inappropriate. However, the present inventors have found that although SmAlO ₃ has an orthorhombic perovskite structure (LaAlO ₃ structure), it is suitable for use as a member for an electrostatic chuck.
That is, by including a perovskite crystal, the dielectric constant of the corrosion-resistant member can be increased, and when the corrosion-resistant member of the present invention is used for an electrostatic chuck member, the adsorption force of the electrostatic chuck when an electric field is applied And the residual chucking force of the electrostatic chuck when the application of the electric field is stopped can be made weaker.

  Further, the perovskite type crystal in the composite oxide according to the present invention is preferably 50% by volume or more, and more preferably 80% by volume or more. The ratio of perovskite crystals can be confirmed by quantitative analysis by powder X-ray diffraction.

If the samarium is not uniformly dispersed at the stage of manufacturing the sintered body to be the corrosion resistant member, that is, if the samarium is segregated on the surface, black spots may be generated on the surface of the sintered body. This black spot is caused by segregation of Sm ₂ O ₃ , and when sintered in a vacuum or in an inert atmosphere, it is presumed that metal samarium is likely to be reduced by reduction, and residual adsorption and dielectric loss increase when an electrostatic chuck is used. Is done. In addition, characteristics such as dielectric constant and adsorption force may not be stabilized.

The above-mentioned black spots are present on the surface more than can be visually confirmed, and in particular often affect the adsorption force, residual adsorption and dielectric loss. Therefore, in the corrosion-resistant member of the present invention, the number of segregated portions derived from samarium having a maximum length of 0.1 mm or more that is present on at least one main surface is 10 or less. The number of segregation parts derived from the samarium is preferably 5 or less, and more preferably 0. When the number of segregation parts derived from samarium exceeds 10, it is estimated that residual adsorption and dielectric loss increase when an electrostatic chuck is used.
In addition, even if the segregation part derived from samarium having a maximum length of less than 0.1 mm is present, the effect of the present invention is not greatly affected.

A samarium-derived segregation part having a maximum length of 0.1 mm or more can be measured with an optical microscope or the like.
The above “at least one main surface” means, for example, at least one flat surface when the corrosion-resistant member of the present invention has a plate shape such as a disk shape. In other words, it refers to a surface that mainly exerts its function when the corrosion-resistant member is applied to various uses, for example, a chuck surface when used as an electrostatic chuck.

  The range of samarium: aluminum (molar ratio) in the composite oxide is preferably 73:27 to 35:65, more preferably 65:35 to 40:60, and 60:40 to 45:55. More preferably. When the range of samarium: aluminum (molar ratio) in the composite oxide is 73:27 to 35:65, the main structure of the composite oxide can be a perovskite crystal.

  The relative dielectric constant (temperature: 25 ° C.) at a frequency of 40 Hz of the corrosion-resistant member of the present invention is preferably 20 or more, more preferably 23 or more, and further preferably 25 or more. When the relative dielectric constant of the corrosion-resistant member of the present invention is 20 or more, when the corrosion-resistant member is used for the electrostatic chuck member, the adsorption force of the electrostatic chuck when an electric field is applied can be increased.

  The relative density in the corrosion-resistant member of the present invention is preferably 97% or more, more preferably 97.5% or more, and further preferably 98% or more. When the relative density of the corrosion-resistant member is 97% or more, the strength of the corrosion-resistant member can be increased and the relative dielectric constant of the corrosion-resistant member can be increased. Further, since pores in the corrosion-resistant member cause an increase in dielectric loss, the dielectric loss of the corrosion-resistant member can be reduced when the relative density in the corrosion-resistant member is 97% or more.

  Electrostatic adsorption force when the corrosion-resistant member of the present invention is processed to a thickness of 1 mm, bonded with an alumina ceramic / electrode / sintered structure, and a voltage of 2.0 kv is applied at a sample mounting surface temperature of 25 ° C. Is preferably 12 kPa or more, more preferably 13 kPa or more, and even more preferably 15 kPa. When the electrostatic attraction force is 12 kPa or more, a substrate such as a silicon wafer can be reliably fixed to the electrostatic chuck by using the electrostatic chucking force as a member for electrostatic chuck.

  Moreover, after processing the corrosion-resistant member of the present invention to a thickness of 1 mm, bonding with a configuration of alumina ceramic / electrode / sintered body, and applying an applied voltage of 2.0 kv at a sample mounting surface temperature of 25 ° C. for 60 seconds, The residual adsorptive force measured immediately after the voltage application is released is preferably 1 kPa or less, more preferably 0.9 kPa or less, and even more preferably 0.8 kPa or less. When the residual adsorption force is 1 kPa or more, the substrate can be easily removed from the electrostatic chuck after predetermined processing on the substrate such as a silicon wafer is completed by using the corrosion-resistant member of the present invention for the electrostatic chuck member. Can be removed.

  The dielectric loss of the corrosion-resistant member of the present invention at a frequency of 40 Hz is preferably 0.1 or less, and more preferably 0.05 or less. When the dielectric loss is 0.1 or less, the residual adsorption is reduced and the dielectric loss can be favorably used.

  Further, the bending strength of the corrosion-resistant member of the present invention is preferably 150 MPa or more, more preferably 160 MPa or more, and further preferably 170 MPa or more. Here, the bending strength is measured by a four-point bending test in accordance with JIS R1601. When the corrosion-resistant member has a bending strength of 150 MPa or more, when the corrosion-resistant member is used as an electrostatic chuck member, there is no practical problem with respect to strength.

[Method of manufacturing corrosion-resistant member]
The corrosion-resistant member of the present invention is manufactured through the following steps, for example.
That is, (A) a raw material powder dispersion liquid preparation step for preparing a raw material powder dispersion liquid in which the particle size distribution d50 of the raw material powder is 0.5 μm or less and d90 is 0.9 μm or less, and (B) obtained from the previous step. After obtaining the raw material mixed powder by spray-drying the raw material powder dispersion, the molding step of molding and degreasing the raw material mixed powder, (C) the firing step of sintering the compact after degreasing, and (D) this step And an annealing treatment step of annealing the sintered body obtained in (1).
Hereinafter, each process will be described.

(A) Raw material powder dispersion preparation step:
A composite oxide containing samarium and aluminum and containing a perovskite crystal (samarium / aluminum / perovskite: SAP) is a mixture of Sm ₂ O ₃ powder and Al ₂ O ₃ powder and subjected to reactive sintering at high temperature. Thus, a sintered body is obtained. However, simply mixing may increase the residual adsorption of the sintered body and increase the dielectric loss. That is, in a method in which Al ₂ O ₃ powder and Sm ₂ O ₃ powder are dispersed and mixed in water and the dispersion slurry is dried by spray drying to obtain a raw material mixed powder, Sm ₂ O ₃ is more than Al ₂ O _3. Since the specific gravity is large, it precipitates in the dispersed slurry. As a result, black spots are caused in the sintered body, segregation of Sm ₂ O ₃ occurs due to the addition of conductivity, and when sintered in a vacuum or in an inert atmosphere, metal samarium is easily reduced due to reduction. It is presumed that adsorption and dielectric loss will increase.

In the production method according to the corrosion-resistant member of the present invention, in this raw material powder dispersion preparation step, the Sm ₂ O ₃ powder and the Al ₂ O ₃ powder are uniformly mixed by improving the dispersibility of the raw material powder dispersion, Since reaction sintering occurs uniformly, segregation of Sm ₂ O ₃ can be prevented.

The raw material powder dispersion preparation step will be described more specifically.
First, in this step, a powder (raw material powder dispersion) is prepared by mixing and dispersing a powder as a raw material of each crystal phase in a solvent.

The particle diameters of the Al ₂ O ₃ powder and the Sm ₂ O ₃ powder that are raw material powders are preferably about 0.01 to 1 μm. When the particle size is about 1 μm or less, the surface free energy necessary for sintering is not insufficient, and a dense sintered body is easily obtained. Moreover, if it is about 0.01 micrometer or more, it will not become expensive commercially but can prevent an increase in cost.

  A solvent is used to mix and make a slurry of the raw material powder, but the solvent to be used is not limited, and examples thereof include water and alcohol.

As a dispersion method, first, a dispersant is added to Sm ₂ O ₃ powder having a high specific gravity, stirring and ultrasonic treatment are performed, and preliminary dispersion is performed to prepare an Sm ₂ O ₃ dispersion. Examples of the dispersant include a polymethacrylic acid dispersant, an acrylic copolymer, and an alkyl ammonium salt. Further, the dispersant is preferably about 5 to 10 wt% relative to _Sm 2 _{O 3} powder.
The obtained dispersion is dispersed and pulverized by a wet atomizer using ultra-high pressure.

Apart from Sm ₂ O ₃ powder, Al ₂ O ₃ powder is added to the solvent, and stirring and ultrasonic treatment are performed to prepare an Al ₂ O ₃ dispersion. A dispersant may or may not be used for the Al ₂ O ₃ powder. It is preferable to use a polycarboxylic acid-based dispersant as the dispersion. Further, the dispersant is preferably about 5 to 10 wt% with respect to _Al 2 _{O 3} powder.
Thereafter, the Al ₂ O ₃ dispersion and the Sm ₂ O ₃ dispersion are mixed and stirred and sonicated, and the obtained mixed dispersion is dispersed and pulverized with a wet atomizer to obtain a particle size distribution. A fine slurry (raw powder dispersion) is obtained.

  As the characteristics of the particle size distribution of the raw material powder in the obtained slurry, the volume-based d50 (50% cumulative diameter) measured by laser diffraction / scattering method is 0.5 μm or less, and d90 (90% cumulative diameter) is 0.9 μm. The following is preferable. When d50 is 0.5 μm or less and d90 is 0.9 μm or less, segregation of samarium oxide is difficult to occur, and the generation of black spots can be suppressed or eliminated.

(B) Molding process:
In this step, the slurry obtained in step (A) is granulated into granules, and the granules are further molded into a desired molded body. A spray dryer or the like is preferably used as a method for granulating the slurry into a granular shape. The granules thus obtained are molded by a known molding means, and then degreased at about 50 to 600 ° C. in the atmosphere.

(C) Firing step:
In this step, the molded body obtained in step (B) is fired. A dense sintered body having a relative density of 97% or more can be produced by firing at 1300 ° C. to 1800 ° C. for about 1 to 3 hours in the air or in an inert gas atmosphere. When the temperature is 1300 ° C. or higher, sintering proceeds well, and the density of the obtained sintered body can be improved. Moreover, melt | dissolution can be prevented by setting it as 1800 degrees C or less.

  As a firing method, normal pressure firing may be used, but in order to obtain a dense sintered body, a pressure firing method such as hot pressing or hot isostatic pressing (HIP) is preferable. The pressure applied during pressure firing is not particularly limited, but is usually about 10 to 40 MPa.

(D) Annealing process:
In this step, the sintered body obtained in step (C) is heat-treated in the atmosphere. The annealing treatment temperature is preferably 1280 ° C to 1600 ° C, and the treatment time is preferably 2 to 12 hours. By setting the annealing temperature to 1280 ° C. or higher, oxygen defects can be eliminated. Moreover, favorable adsorption power can be maintained by setting it as 1600 degrees C or less. Moreover, if the treatment time is 2 hours or longer, oxygen defects can be eliminated, and if the treatment time is 12 hours or shorter, a good adsorption force can be maintained.

  Through the above steps, a known treatment is appropriately performed to produce the corrosion-resistant member of the present invention.

As described above, in the manufacturing method according to the corrosion-resistant member of the present invention, since specific dispersion treatment is performed in the raw material dispersion preparation step, the Sm ₂ O ₃ powder and the Al ₂ O ₃ powder are uniformly distributed. A ligation can be obtained.
This, Sm ₂ by mixing with _Sm 2 _{O 3} powder by performing the process at high pressure disperser to fine enough grain size at the beginning of the advance to prepare a _Sm 2 _{O 3} dispersion, _Al 2 _{O 3} dispersion This is because a slurry in which O ₃ powder and Al ₂ O ₃ powder are uniformly mixed is obtained. And a uniform raw material mixed powder is obtained by drying this slurry. By using this uniform raw material mixed powder, segregation of Sm in the sintered body can be prevented, generation of black spots on the surface of the corrosion-resistant member can be suppressed, a large adsorption force can be obtained, and an increase in dielectric loss or residual can be obtained. An increase in adsorption force can be suppressed.

[Electrostatic chuck members]
The electrostatic chuck member of the present invention includes the corrosion-resistant member of the present invention. The electrostatic chuck member includes, for example, a plate-like body having a sample mounting surface for electrostatically adsorbing a sample, an internal electrode layer for electrostatic adsorption provided on the back surface, and an internal electrode layer for electrostatic adsorption And an insulating material layer provided on the opposite side of the adhesive layer from the plate-like body. The corrosion-resistant member of the present invention is used on at least the sample mounting surface of the plate-like body in the electrostatic chuck member.

  Since the electrostatic chuck member of the present invention includes the corrosion-resistant member of the present invention, the electrostatic chuck when the electric field is applied is made stronger than before and the application of the electric field is stopped. The residual adsorbing power can be made even weaker than before.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.

Measurements and evaluations in Examples and Reference Examples described below were performed as follows.
(1) Relative density of corrosion resistant member The density of the corrosion resistant member obtained in Examples and Reference Examples was measured by the Archimedes method, and the relative density was calculated by dividing the measured density by the theoretical density obtained by the following formula. .
Unit cell weight (g) = unit cell weight of samarium aluminum oxide crystal phase × mol% of each crystal phase
Unit cell volume (cm ³ ) = unit cell volume of samarium aluminum oxide crystal phase × mol% of each crystal phase
Theoretical density (g / cm ³ ) = unit cell weight / unit cell volume The mol% of each crystal phase% of samarium aluminum oxide was calculated from the charged amount of raw material powder.

(2) Identification of crystal phase of corrosion-resistant member The crystal phase of the corrosion-resistant member obtained in Examples and Reference Examples was identified by a powder X-ray diffraction method. For powder X-ray diffraction, an X-ray diffractometer (manufactured by PANalytical, X'Pert PRO MPD) was used.

(3) Particle Size Distribution of Slurry The particle size distribution of the raw material powder in the slurry was measured using Shimadzu Corporation model name “SALD-2000J” as a measuring device to obtain d50 and d90.

(4) Relative permittivity and dielectric loss of sintered body After processing the corrosion resistant member obtained in Examples and Reference Examples to φ48 × 1 mm, the relative permittivity of the corrosion resistant member in the frequency range from 40 MHz to 1 MHz is charged / discharged. It measured using the evaluation apparatus (Toyo System Co., Ltd. product, TOSCAT-3000).

(5) Adsorption power and residual adsorption power / adsorption power of the sintered body The corrosion-resistant member obtained in Examples and Reference Examples was processed to a thickness of 1.0 mm, and an electrode was placed between the processed corrosion-resistant member and alumina ceramics. An embedded adhesive layer was formed to produce an electrostatic chuck. The sample mounting surface temperature of the electrostatic chuck was set to 25 ° C., and a voltage of 2.0 kV was applied to the electrodes for 60 seconds to adsorb the 1 inch silicon wafer to the electrostatic chuck in vacuum (<0.5 Pa). . And the adsorption power with respect to a 1-inch silicon wafer was measured. The measurement was performed by peeling using a load cell, and the maximum peeling stress generated at that time was taken as the adsorption force.

-Residual adsorption force Corrosion resistant members obtained in the examples and reference examples were processed to a thickness of 1.0 mm, and an adhesive layer was formed by embedding electrodes between the processed corrosion resistant members and alumina ceramics. Produced. The sample mounting surface temperature of the electrostatic chuck was set to 25 ° C., and a voltage of 2.0 kV was applied to the electrodes for 60 seconds to adsorb the 1 inch silicon wafer to the electrostatic chuck in vacuum (<0.5 Pa). . Thereafter, the application of voltage was stopped, and the residual adsorption force with respect to the 1-inch silicon wafer immediately after the application of voltage was stopped was measured. The measurement was performed by peeling using a load cell, and the maximum peeling stress generated at that time was defined as the residual adsorption force.

(6) Evaluation of black spot on corrosion-resistant member surface The number of black spots having a maximum length of 0.1 mm or more was counted with an optical microscope.

(7) Corrosion resistance evaluation Gases of (i) CF ₄ / O ₂ / Ar (2/2/16 mL / min) and (ii) SF ₆ (10 mL / min) were applied to the corrosion resistant members obtained in the examples and reference examples. The seed was irradiated and a plasma exposure test was performed. The conditions were vacuum degree: 1 mTorr, electrode frequency: 2.5 GHz, bias frequency: 13.56 MHz, voltage: 3400 V, current: 1.8 A, plasma power: 420 W (CF ₄ ) and 400 W (SF ₆ ).
The surface roughness of the unexposed part and the exposed part was measured, and the etching rate was calculated from the difference.

Example 1
(A) Raw material powder dispersion preparation step:
Commercially available (Daimei Chemical Co., Ltd., model number: TM-5D) aluminum oxide (Al ₂ O ₃ ) powder and commercially available (Yttrium Japan, model number: N-SM3CP) samarium oxide (Sm ₂ O) ₃ ) Each powder was weighed so as to have the raw material composition shown in Table 1.
Then, was added 5 wt% of the dispersing agent to _Sm 2 _{O 3} powder in _Sm 2 _{O 3} powder, adding water as a solvent, was adjusted to an aqueous solution of 30 wt%. Stirring and ultrasonic treatment were performed, and preliminary dispersion was performed to prepare an Sm ₂ O ₃ dispersion.

A polymethacrylic acid type dispersant was used as the dispersant. The Sm ₂ O ₃ dispersion was dispersed and pulverized by a wet atomization apparatus (apparatus name: Starburst, manufactured by Sugino Machine Co., Ltd.) using ultra high pressure.
Apart from Sm ₂ O ₃ powder, Al ₂ O ₃ powder was added to an aqueous solvent, and stirring and ultrasonic treatment were performed to prepare an Al ₂ O ₃ dispersion (Al ₂ O ₃ : 30% by mass). Thereafter, the Al ₂ O ₃ dispersion and the Sm ₂ O ₃ dispersion are mixed and stirred and sonicated, and the obtained mixed dispersion is dispersed and pulverized by a wet atomizer to obtain a slurry. It was.
A part of the slurry after dispersion was taken, and the particle size distribution (d50 and d90) of the raw material powder was measured. The results are shown in Table 1.

(B) Molding step, and (C) Firing step:
This slurry was granulated with a spray dryer to form granules. Next, this granule was molded into a predetermined shape. Subsequently, this molded body was heated in the atmosphere at 500 ° C. for 4 hours to perform a degreasing treatment. Using a hot press, it was subjected to pressure firing at 1500 ° C. for 2 hours in argon to obtain a sintered body. The pressing force at this time was 20 MPa.

(D) Annealing process:
The obtained sintered body was subjected to heat treatment (annealing treatment) at 1480 ° C. for 10 hours in the atmosphere to produce a corrosion-resistant member.
The obtained corrosion-resistant member was evaluated by X-ray diffraction measurement, relative dielectric constant measurement, and adsorption force measurement. Table 1 shows the properties of the obtained corrosion-resistant member. Moreover, the photograph of the one main surface of the produced corrosion-resistant member is shown in FIG.

(Example 2)
A commercially available aluminum oxide (Al ₂ O ₃ ) powder and a commercially available samarium oxide (Sm ₂ O ₃ ) powder are weighed so as to have the raw material composition shown in Table 1, and 1% by weight of the Sm ₂ O ₃ powder is dispersed. Except that the agent was added to the Sm ₂ O ₃ powder, the same procedure as in Example 1 was performed to prepare a corrosion-resistant member, and the obtained sintered body was evaluated. The results are shown in Table 1.

Example 3
A commercially available aluminum oxide (Al ₂ O ₃ ) powder and a commercially available samarium oxide (Sm ₂ O ₃ ) powder were weighed so as to have the composition shown in the raw materials of Table 1, and used for the Sm ₂ O ₃ powder. A corrosion-resistant member was produced in the same manner as in Example 1 except that the agent was an acrylic copolymer dispersant, and the obtained sintered body was evaluated. The results are shown in Table 1.

(Reference Example 1)
(A) Raw material powder dispersion preparation step:
Commercially available aluminum oxide (Al ₂ O ₃ ) powder and commercially available samarium oxide (Sm ₂ O ₃ ) powder were weighed so as to have the raw material compositions shown in Table 1. 1% by mass of a dispersant was added to the Al ₂ O ₃ powder, and ultrasonic treatment was performed using water as a solvent to perform dispersion. Dispersion was performed by adding 5% by mass of a dispersant to the Sm ₂ O ₃ powder and performing ultrasonic treatment using water as a solvent. Each dispersion was mixed and then dispersed with a high-pressure disperser to obtain a slurry. A part of the slurry after dispersion was taken and the particle size distribution was measured.
The steps (B) to (D) were the same as in Example 1, and the obtained corrosion-resistant member was evaluated. The results are shown in Table 1. Moreover, the photograph of the one main surface of the produced corrosion-resistant member is shown in FIG.

(Reference Example 2)
Commercially available aluminum oxide (Al ₂ O ₃ ) powder and commercially available samarium oxide (Sm ₂ O ₃ ) powder were weighed so as to have the raw material compositions shown in Table 1. A dispersant was not added, and water was used as a solvent to stir the Al ₂ O ₃ powder and the Sm ₂ O ₃ powder to obtain a dispersion. The subsequent steps were performed in the same manner as in Example 1, and the obtained corrosion-resistant member was evaluated. The results are shown in Table 1.

In the evaluation of corrosion resistance, in all the examples and reference examples, “(CF ₄ / O ₂ ) Ar” in (i) is within a range of 0.01 to 0.1 μm / hr, and (ii) “SF ₆ / Ar” was in the range of 0.1 to 0.5 μm / hr, and good corrosion resistance could be confirmed.

In each of the examples, since the predetermined dispersion treatment was performed in the raw material powder dispersion preparation step, the distribution of Sm ₂ O ₃ and Al ₂ O ₃ became uniform, and a corrosion-resistant member in which the generation of black spots on the surface was suppressed was obtained. (See FIG. 1). As a result, compared with the reference example, a large attractive force was exhibited, and a low dielectric loss and a low residual attractive force were obtained. In the reference example, the occurrence of black spots as shown in FIG. 2 was confirmed.

Claims (3)

A corrosion-resistant member substantially composed of a composite oxide containing samarium and aluminum,
The composite oxide includes a perovskite crystal;
A corrosion-resistant member having 10 or less segregation parts derived from the samarium having a maximum length of 0.1 mm or more, which is present on at least one main surface of the corrosion-resistant member.   The corrosion-resistant member according to claim 1, wherein the relative density of the corrosion-resistant member is 97% or more.   An electrostatic chuck member comprising the corrosion-resistant member according to claim 1.