JPH09283607A - Electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the excessive lowering of the resistance value of an insulating part even when the temperature rise of an electrostatic chuck, to improve the corrosion resisting property of the electrostatic chuck against the plasma of halogen gas, and to improve the mechanical strength and the thermal shock resistance of the electrostatic chuck. SOLUTION: This electrostatic chuck 8 is provided with an electrode 3 and insulating parts 1 and 2 which are formed on both sides of the electrode 3. At least the insulating part 1 on the side of an attracting surrace 6 consists of a composite sintered body. This composite sintered body contains aluminum oxide and silicon carbide, silicon carbide grains are brought into contact with each other through mullite material, and the cubical intrinsic resistance value in room temperature of the composite sintered body is between 1×10<8> and 1×10<15> Ω/cm. The desirable content of the silicon carbide in the composite sintered body is between 5 and 30wt.%, the mullite material in the composite sintered body is present as oxide of 0.1μm or smaller in thickness on the surface of the silicon carbide grains.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor wafer,
Adheres metal wafers, glass plates, etc. by electrostatic force,
The present invention relates to an electrostatic chuck for holding.

[0002]

2. Description of the Related Art For example, when manufacturing a semiconductor, a liquid crystal, or the like, a vacuum chuck or a clamp is used as a method for fixing a semiconductor wafer or a glass plate. However, the fixing method using a vacuum chuck cannot be adopted because there is no pressure difference under vacuum conditions. In the mechanical fixing method using a clamp, the fixed part of the semiconductor wafer or glass plate cannot be used as a device, and the semiconductor wafer or glass plate is partially distorted. Have a problem.

As a solution to the above problems of the conventional technique, a ceramic electrostatic chuck utilizing electrostatic force has begun to attract attention. As a material of the ceramic electrostatic chuck, a composite sintered body containing titanium oxide in alumina (Japanese Patent Laid-Open No. 62-94953 and Japanese Patent Laid-Open No. 3-204924) and titanium nitride in ceramics such as alumina are used. Composite sintered body (Japanese Patent Laid-Open No. 6-80
No. 89) has been proposed.

[0004]

However, in an electrostatic chuck having an insulating portion made of titanium oxide contained in alumina, the temperature dependence of the resistance value of the composite sintered body is large, so that the plasma When the temperature of the electrostatic chuck rises due to such factors as described above, the resistance value of the insulating portion is lowered, an excessive current flows through the wafer, and the circuit of the wafer is broken.

Titanium oxide has poor corrosion resistance to plasma of halogen gases such as CF ₄ and BCl ₃ .
Plasma etching device using these halogen-based gases as etching or cleaning gas, CV
There are restrictions on the use of the D device. Furthermore, the alumina containing titanium oxide has lower strength than the alumina containing no titanium oxide. In addition, since the thermal expansion coefficient is large, the thermal shock resistance is poor, and there is a high risk of damage due to thermal stress when used at high temperatures.

On the other hand, in an electrostatic chuck provided with an insulating portion made by containing titanium nitride in ceramics such as alumina, surface deterioration due to oxidation of titanium nitride is remarkable in an etching gas atmosphere containing oxygen. . Further, as with the alumina containing titanium oxide, CF ₄ , BCl
Corrosion resistance of halogen-based gases such as _{3 to} plasma is poor, and there are restrictions on the use in plasma etching equipment, CVD equipment, etc., which use these gases as etching or cleaning gases.

The present invention prevents the resistance value of the insulating portion from excessively decreasing when the temperature of the electrostatic chuck rises, improves the corrosion resistance of the electrostatic chuck to the plasma of halogen gas, and It is also to improve its strength and thermal shock resistance.

[0008]

SUMMARY OF THE INVENTION The present invention is an electrostatic chuck comprising an electrode and insulating portions provided on both sides of the electrode, wherein at least the insulating portion on the suction surface side is a composite burner. The composite sintered body contains aluminum oxide and silicon carbide particles, and the silicon carbide particles are in contact with each other through a mullite substance. Volume resistivity of 1 × 10 ⁸ Ω · cm or more, 1 × 10 ¹⁵ Ω · cm
The present invention relates to an electrostatic chuck, characterized in that:

In a preferred embodiment of the present invention, the content of carbon silicon in the composite sintered body is 5% by weight or more and 30% by weight or less. In another preferred embodiment, the mullite substance in the composite sintered body is present on the surface of the silicon carbide particles as an oxide having a thickness of 0.1 μm or less.

In still another preferred embodiment, the composite sintered body has a mean particle size of 0.5 μm or less and a silicon carbide powder having an oxide film with a thickness of 0.05 μm or less on the surface layer, and an aluminum oxide powder. And a sintered body of the mixed powder of and in a non-oxidizing atmosphere. In still another preferred embodiment, the average particle diameter of the silicon carbide particles in the composite sintered body is 1 μm.
It is as follows.

The inventor of the present invention has conducted various studies to develop an electrostatic chuck having a low temperature dependence of electric conductivity, excellent corrosion resistance to halogen gas, high hardness and strength, and high heat resistance. As the material of the electrostatic chuck,
It has been found that a composite sintered body containing aluminum oxide and silicon carbide and having silicon carbide particles in contact with each other through a mullite substance is suitable.

That is, at least the adsorption surface side of the insulating portion of the electrostatic chuck contains aluminum oxide and silicon carbide, the silicon carbide particles are in contact with each other through the mullite substance, and the volume resistivity at room temperature is 1 × 10 ⁸ Ω ・
It was decided to form a composite sintered body having a size of 1 cm or more and 1 × 10 ¹⁵ Ω · cm or less. "Mullite substances" here
The term generically refers to a solid solution or glass of aluminum oxide and mullite, or a solid solution or glass of silicon oxide and mullite.

That is, since the electrostatic chuck formed of this composite sintered body is less corroded by the plasma of halogen gas and is superior in strength and hardness as compared with alumina, it is less likely to generate particles, and Has excellent heat resistance and there is no risk of damage due to thermal stress when used at high temperatures. By controlling the particle size of the composite sintered body, the amount of silicon carbide, and the amount of the mullite substance present, the volume resistivity value is 1 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁵ Ω ·
The value is set to cm or less.

The content of silicon carbide in the composite sintered body is preferably 5% by weight or more and 30% by weight or less. That is, although depending on the particle size of the sintered body and the like, when the content of silicon carbide is 5% by weight or more, the effect of increasing the hardness and strength of the composite sintered body by adding silicon carbide becomes remarkable. , And the volume resistivity is 1 × 10 ¹⁵ Ω · cm
Because of the following, the responsiveness of adsorption / desorption of wafers and the like is improved. On the other hand, when the content of silicon carbide is 30% by weight or less, the volume resistivity becomes 1 × 10 ⁸ Ω · cm or more, so that the leak current from the electrostatic chuck to the wafer can be suppressed and the device can be destroyed. Less risk of

Further, the mullite in the composite sintered body is preferably present on the surface of the silicon carbide particles as an oxide having a thickness of 0.1 μm or less. That is, the electrical conductivity of the composite sintered body is mainly due to silicon carbide. Therefore, in the composition region where the silicon carbide particles in the composite sintered body are in direct contact with each other to form a conductive path, the electric resistance sharply decreases and it becomes difficult to control the resistance value. Therefore,
When an appropriate amount of mullite substance is present on the surface of silicon carbide particles,
Since the silicon carbide particles in the composite sintered body are in contact with each other through the mullite substance, there is no sudden decrease in electric resistance and the resistance value can be controlled well.

Here, if the thickness of the mullite oxide existing on the surface of the silicon carbide particles exceeds 0.1 μm, the resistance between the silicon carbides in the composite sintered body increases and the volume resistivity at room temperature increases. Of more than 1 × 10 ¹⁵ Ω · cm, the adsorption / desorption responsiveness of wafers and the like may be deteriorated, and the corrosion resistance of the halogen-based gas to plasma may be deteriorated. Therefore, it is preferable that the thickness of the mullite oxide is 0.1 μm or less.

A small amount of impurities is allowed in the composite sintered body. However, the decrease in lifetime and gate voltage in the semiconductor manufacturing process is due to the transition metal element and the alkali metal. In addition, aluminum,
If the amount of metal impurities other than silicon exceeds 0.1% by weight, the semiconductor wafer is more likely to be contaminated, and the temperature dependence of the electric resistance of the electrostatic chuck increases.
Not preferred. Therefore, the content of metal impurities other than aluminum and silicon in the composite sintered body forming the insulating portion is preferably 0.1% by weight or less.

Further, in the above composite sintered body, a mixed powder consisting of an aluminum oxide powder and a silicon carbide powder having an oxide film with an average particle diameter of 0.5 μm or less and a thickness of 0.05 μm or less on the surface layer is non-oxidized. It can be produced by sintering in a strong atmosphere.

That is, in a composite sintered body using a silicon carbide powder having an average particle diameter exceeding 0.5 μm, the average particle diameter of silicon carbide in the sintered body exceeds 1 μm, and the strength of the composite sintered body is increased. The effect of increase is small, and when exposed to plasma, the electric field concentrates on the silicon carbide portion and is greatly damaged, which is not preferable. In addition, the thickness of the surface of the silicon carbide particles is 0.05
By using the silicon carbide powder having an oxide film of not more than μm, the silicon oxide on the surface of the silicon carbide particles and the aluminum oxide can be reacted with each other to form an insulating film of mullite oxide on the surface of the silicon carbide particles, This makes it possible to suppress a sharp decrease in the resistance value.

The silicon carbide raw material powder used is preferably a powder obtained by a plasma CVD method. In particular, a raw material gas of a silane compound or silicon halide and hydrocarbon is introduced into plasma in a non-oxidizing atmosphere, and a gas phase reaction is performed while controlling the pressure of the reaction system within the range of less than 1 atm to 0.1 Torr. The average particle size obtained was 0.1μ
The ultrafine powder having a particle size of m or less has excellent sinterability, has high purity, and has a spherical particle shape, and therefore has good dispersibility during molding.

On the other hand, the aluminum oxide raw material powder is not particularly limited as long as it has a high purity. Further, by setting the atmosphere during sintering to a non-oxidizing atmosphere, excessive oxidation of silicon carbide during sintering can be suppressed. Known means can be adopted for the molding method and the sintering method during the production of the composite sintered body.

Furthermore, by setting the average particle size of the silicon carbide particles in the composite sintered body to 1 μm or less, the effect of improving the strength by adding silicon carbide is remarkable, and the electric field when exposed to plasma is the silicon carbide portion. It is preferable because there is no danger of being seriously damaged by being concentrated on.

The specific form and manufacturing method of the electrostatic chuck of the present invention are not particularly limited. A suitable electrostatic chuck configuration and manufacturing method will be described with reference to FIGS. 1 and 2. 1A is a plan view showing the disk-shaped insulating portion 1 on the attracting surface side, and FIG. 1B is a plan view showing the disk-shaped insulating portion 2 on the base side of the electrostatic chuck. FIG.
In order to manufacture the disk-shaped insulating portion 1 of (a), first, a disk-shaped sintered body is manufactured, and a through hole 1a is formed in this disk-shaped sintered body by machining. Disk-shaped insulating portion 2 of FIG. 1 (b)
In order to manufacture, the disk-shaped sintered body is manufactured first, and the through-hole 2a and the electrode insertion hole 2b are formed in this disk-shaped sintered body by machining. At least the insulating portion 1 is formed of the composite sintered body of the present invention.

Then, as shown in FIG. 2 (a), in a region A within a circle having a radius of 90 mm from the center of the disk-shaped insulating portion 2,
A conductive material is applied to form a coating layer 15, and an insulating material is applied to the outer peripheral edge region B outside the circular region A to form a coating layer 16. Examples of such a conductive material include a mixed powder of a conductive ceramics powder such as tantalum carbide and titanium nitride and an aluminum oxide-silicon dioxide glass powder. Examples of such an insulating material include various glass powders such as aluminum oxide-silicon dioxide glass. In this state, the disk-shaped insulating portions 1 and 2 are superposed and heat-treated to bond them to each other to obtain the electrostatic chuck 8 as shown in FIG. 2B.

In FIG. 2B, a circular electrode 3 made of a conductive material is formed, and an insulating portion 1 is provided on the adsorption surface 6 side when viewed from the electrode 3. A lead-out electrode 14 made of a conductive ceramic such as tantalum carbide or titanium nitride is inserted into the electrode insertion hole 2b of the disk-shaped insulating portion 2, and the lead-out electrode 14 is formed on the electrode 3 by a brazing material such as active metal or silver brazing. Join to each other.

[0026]

【Example】

(Example 1) [Production of electrostatic chuck] β-type silicon carbide ultrafine powder having an average particle diameter of 0.05 µm was vapor-phase synthesized by a plasma CVD method. This powder was heat-treated in air at 350 ° C. for 50 hours to obtain silicon carbide ultrafine powder having a 0.002 μm-thick oxide film of silicon dioxide on the surface. The thickness of this oxide film was calculated from the measurement results of the amount of oxygen and the specific surface area of the ultrafine silicon carbide powder.

8% by weight of this ultrafine silicon carbide powder and 92% by weight of aluminum oxide powder having an average particle diameter of 0.5 μm were mixed for 5 hours using an ultrasonic disperser to obtain a mixed powder. The mixed powder was dried, shaped, and then sintered for 2 hours under a condition of an argon atmosphere and a temperature of 1700 ° C. to obtain two disc-shaped composite sintered bodies having a diameter of 195 mm and a thickness of 4 mm.

Then, the average particle diameter and the volume resistivity of the silicon carbide particles in this composite sintered body were measured, and the results are shown in Table 1. The average particle diameter of the silicon carbide particles was measured by the SEM observation method, and the volume resistivity value was
The measurement was performed according to the method specified in "JIS C2141".

Further, it was confirmed by TEM observation that adjacent silicon carbide particles were in contact with each other in the composite sintered body via a mullite oxide having a thickness of 0.005 μm.

Further, the Vickers hardness and room temperature 4-point bending strength of the above-mentioned separately prepared composite sintered body were measured according to "JIS R160".
It was measured according to the method specified in "1". Table 1 shows the results.

Then, the disc-shaped sintered body is machined,
Each disk-shaped insulating portion shown in FIGS. 1A and 1B was manufactured. However, in FIG. 1A, a through hole 1 a having a diameter of 15 mm is formed in the center of the insulating portion 1. In FIG. 1B, a through hole 2 having a diameter of 15 mm is formed at the center of the insulating portion 2.
Form a, and place a diameter of 1 mm at a location 25 mm away from the center.
An electrode insertion hole 2b of 0 mm was formed.

Then, the radius of 9 mm from the center of the disk-shaped insulating portion 2
In the circular area A within 0 mm, tantalum carbide (30 vol
%) And aluminum oxide-silicon dioxide glass powder (7
The mixed powder with 0 vol%) was applied by screen printing. Outer peripheral region B (radius 90 to radius 97.5
The area (mm) was coated with aluminum oxide-silicon dioxide glass powder by screen printing. Insulation part 1
After the layers 2 and 2 were overlapped with each other, heat treatment was performed to bond them.

Next, after grinding the disk-shaped insulating portion 1 for 1.3 mm, a lead-out electrode 14 made of tantalum carbide is inserted into the electrode insertion hole 2b of the insulating portion 2 and joined by using a silver brazing agent. The electrostatic chuck 8 shown in FIG. 2B was produced.

[Measurement of Electrostatic Characteristic] The electrostatic chucking force thus prepared, the electrostatic chucking force, the chucking time, and the desorbing time are measured at room temperature and 400 ° C. at the respective temperatures shown in FIG. Was measured using.

That is, the heater 9 is installed on the table 10,
The electrostatic chuck 8 was installed on the heater 9. The pressing member 11 was inserted into the through hole 10 a of the table 10, the through hole 9 a of the heater 9, and the through hole of the electrostatic chuck 8. An 8-inch silicon wafer 18 was placed on the attraction surface 6 of the electrostatic chuck 8. Pressing member 11 against silicon wafer 18
The upper ends of the. A voltage of 300 V DC is applied between the silicon wafer 18 and the take-out electrode 14, and the silicon wafer 18 is electrostatically adsorbed for 5 minutes.
The lifter 12 lifted the electrostatically adsorbed silicon wafer 18 to remove it. The desorption force required at this time was measured by a load cell and used as the electrostatic adsorption force.

The adsorption time is the time until the electrostatic adsorption force reaches 10 kgf / cm ² when a DC voltage of 300 V is applied, and the desorption time is a DC voltage of 300 V for 5 minutes. It is the time from when the application is stopped after the application to when the electrostatic adsorption force reaches 50 gf / cm ² .
Table 2 shows the measurement results.

Then, the electrostatic chuck was mounted in a plasma CVD apparatus, and 1.0 Torr of CF ₄ 20 vol was used.
%, O _{2 and} 80 vol% of O _{2 and} exposed to plasma in a mixed gas atmosphere for 20 hours, the same electrostatic adsorption characteristic test as described above was performed. Table 3 shows the results.

Further, in each electrostatic adsorption characteristic test before and after exposing the electrostatic chuck to plasma, the temperature up to 400 ° C.
The temperature was raised at a temperature rising rate of ° C / min. As a result, the electrostatic chuck was not damaged or damaged by thermal stress. Therefore, the item of thermal stress resistance in Tables 2 and 3 was described as “good”.

Example 2 Except that the composition of the composite sintered body was 25% by weight of silicon carbide and 75% by weight of alumina.
A composite sintered body was obtained in the same manner as in Example 1. It was confirmed by TEM observation that the silicon carbide particles in this composite sintered body were in contact with each other through a mullite oxide having a thickness of 0.005 μm.

The average particle size and volume resistivity of the silicon carbide particles in this composite sintered body were measured according to Example 1.
Table 1 shows the results. In addition, the Vickers hardness and room temperature four-point bending strength of the above-mentioned composite sintered body prepared separately were determined according to Example 1
It measured according to. Table 1 shows the results. Then, using this composite sintered body, an electrostatic chuck was prepared according to Example 1, and electrostatic adsorption characteristics were measured before and after the halogen gas plasma exposure. The results are shown in Tables 2 and 3.

In each electrostatic adsorption characteristic test before and after exposing the electrostatic chuck to the plasma, 400 ° C.
Although the temperature was raised up to 80 ° C./min, the electrostatic chuck was not damaged or damaged by thermal stress.

Example 3 β having an average particle size of 0.05 μm
Type silicon carbide ultrafine powder was vapor-phase synthesized by the plasma CVD method. This powder was heat-treated at 400 ° C. for 5 hours in the air to obtain a silicon carbide ultrafine powder having a 0.003 μm-thick oxide film of silicon dioxide on the surface. Two disc-shaped composite sintered bodies having a diameter of 195 mm and a thickness of 4 mm were obtained in the same manner as in Example 1 except that this ultrafine silicon carbide powder was used.

The silicon carbide particles in this composite sintered body are
It was confirmed by TEM observation that the mullite oxide having a thickness of 0.004 μm was in contact.

The average particle diameter and volume resistivity of the silicon carbide particles in this composite sintered body were measured according to Example 1.
Table 1 shows the results. In addition, the Vickers hardness and room temperature four-point bending strength of the above-mentioned composite sintered body prepared separately were determined according to Example 1
It measured according to. Table 1 shows the results. Then, using this composite sintered body, an electrostatic chuck was prepared according to Example 1, and electrostatic adsorption characteristics were measured before and after the halogen gas plasma exposure. The results are shown in Tables 2 and 3.

In each electrostatic adsorption characteristic test before and after exposing the electrostatic chuck to plasma, both were 400 ° C.
Although the temperature was raised up to 80 ° C./min, the electrostatic chuck was not damaged or damaged by thermal stress.

Example 4 A composite sintered body was obtained in the same manner as in Example 1 except that the sintering time was 20 hours. It was confirmed by TEM observation that the silicon carbide particles in this composite sintered body were in contact with each other through a mullite oxide having a thickness of 0.009 μm.

The average particle size and volume resistivity of the silicon carbide particles in this composite sintered body were measured according to Example 1.
Table 1 shows the results. The Vickers hardness and room temperature 4-point bending strength of the separately prepared composite sintered body were measured in accordance with Example 1. Table 1 shows the results. Then, using this composite sintered body, an electrostatic chuck was prepared according to Example 1, and electrostatic adsorption characteristics were measured before and after the halogen gas plasma exposure. The results are shown in Tables 2 and 3.

In each of the electrostatic adsorption characteristic tests before and after exposing the electrostatic chuck to plasma, both were 400 ° C.
Although the temperature was raised up to 80 ° C./min, the electrostatic chuck was not damaged or damaged by thermal stress.

(Comparative Example 1) A composite sintered body was obtained in the same manner as in Example 1 except that the composition of the composite sintered body was 100% by weight of aluminum oxide.

The average particle diameter and volume resistivity of the silicon carbide particles in this composite sintered body were measured according to Example 1.
Table 1 shows the results. In addition, the Vickers hardness and room temperature four-point bending strength of the above-mentioned composite sintered body prepared separately were determined according to Example 1
It measured according to. Table 1 shows the results. Then, using this composite sintered body, an electrostatic chuck was prepared according to Example 1, and electrostatic adsorption characteristics were measured before and after the halogen gas plasma exposure. The results are shown in Tables 2 and 3.

In each of the electrostatic adsorption characteristic tests before and after exposing the electrostatic chuck to plasma, both were 400 ° C.
Up to 80 ° C./min. As a result, the peripheral portion of the electrostatic chuck was partially damaged during the electrostatic adsorption characteristic test both before and after the halogen gas plasma exposure.

(Comparative Example 2) A composite was prepared in the same manner as in Example 1 except that β-type silicon carbide ultrafine powder having an average particle size of 0.05 μm which was vapor-phase synthesized by the plasma CVD method was used without heat treatment. A sintered body was obtained. In addition, the fact that the silicon carbide particles in the composite sintered body are in contact with each other is
It was confirmed by EM observation.

The average particle diameter and volume resistivity of the silicon carbide particles in this composite sintered body were measured according to Example 1.
Table 1 shows the results. The Vickers hardness and room temperature 4-point bending strength of the separately prepared composite sintered body were measured in accordance with Example 1. Table 1 shows the results. Then, using this composite sintered body, an electrostatic chuck was prepared according to Example 1, and electrostatic adsorption characteristics were measured before and after the halogen gas plasma exposure. The results are shown in Tables 2 and 3.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

In Examples 1, 2, 3, and 4 of the present invention, a high electrostatic adsorption force was obtained even after exposure to plasma, and the response time of adsorption time and desorption time was good.
High thermal stress resistance. Among these, in Examples 1, 2, and 3, the content of silicon carbide in the composite sintered body was 5% by weight or more and 30% by weight or less, and the thickness of the mullite material was 0.1 μm or less. The silicon carbide particles had an average particle diameter of 0.2 μm or 0.3 μm, but both had a high electrostatic adsorption force at room temperature and 400 ° C., and the electrostatic adsorption characteristics after exposure to plasma were also particularly high.

On the other hand, in Comparative Example 1, the electrostatic adsorption force was low even before the plasma exposure, and the adsorption time was
Desorption time is long. In Comparative Example 2, the electrostatic adsorption property before plasma exposure was good, but 40 after plasma exposure.
The electrostatic attraction force at 0 ° C. was particularly low, and discharge was observed between the silicon wafer and the electrostatic chuck.

[0059]

As described above, according to the electrostatic chuck of the present invention, at least the adsorption surface side of the insulating portion contains aluminum oxide and silicon carbide, and the silicon carbide particles are intercalated by the mullite substance. The volume resistivity at room temperature is 1 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁵ Ω
-By forming a composite sintered body having a size of cm or less, it is less corroded by halogen gas, has better strength and hardness than alumina, has less generation of particles, and has excellent heat resistance at high temperatures. In use, there is no risk of damage due to thermal stress, and moreover, it has good electrostatic adsorption properties.

Further, by setting the content of the above-mentioned silicon carbide in the composite sintered body to 5% by weight or more and 30% by weight or less, the hardness and the strength of the composite sintered body are remarkably improved by the addition of silicon carbide. Therefore, the response of adsorption and desorption of the wafer and the like is good, and the risk of device destruction due to the leak current from the electrostatic chuck to the wafer can be effectively eliminated.

Further, the mullite material in the composite sintered body is
By being present as an oxide having a thickness of 0.1 μm or less on the surface of silicon carbide particles, the volume resistivity of the composite sintered body can be easily controlled, and the adsorption / desorption responsiveness of a wafer or the like, halogen Corrosion resistance of the system gas to plasma is improved.

Further, the composite sintered body has an average particle diameter of 0.5.
The effect of increasing the strength is obtained by using a sintered body of a mixed powder of a silicon carbide powder having an oxide film with a thickness of 0.05 μm or less on the surface layer and an aluminum oxide powder in a non-oxidizing atmosphere. The plasma resistance is remarkably improved, and a predetermined volume resistivity value is obtained.

Further, by setting the average particle size of the silicon carbide particles in the composite sintered body to 1 μm or less, the effect of increasing the strength is remarkable, and when exposed to plasma, the electric field concentrates on the silicon carbide portion and is damaged. I will not receive it.

[Brief description of drawings]

FIG. 1A is a plan view showing a disk-shaped insulating portion on a suction surface side, and FIG. 1B is a plan view showing a disk-shaped insulating portion on a substrate side.

FIG. 2A is a plan view showing a state in which a conductive material and an insulating material are applied onto the disk-shaped insulating portion 2,
(B) is a sectional view of the electrostatic chuck.

FIG. 3 is a schematic view showing a device for measuring the attraction force of an electrostatic chuck.

[Description of sign]

 1 Disc-shaped insulating part on adsorption side 1a Through hole 2 Disc-shaped insulating part on base side 2b Electrode insertion hole 3 Circular electrode 4 Insulating bonding layer 6 Adsorption surface 8 Electrostatic chuck 15 Coating layer of conductive material 16 Insulation Coating layer of conductive material 18 Semiconductor wafer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Inazuma 585 Tomimachi, Funabashi, Chiba Sumitomo Osaka Cement Co., Ltd.

Claims (5)

[Claims] 1. An electrostatic chuck comprising an electrode and insulating portions provided on both sides of the electrode, wherein at least the insulating portion on the suction surface side is formed of a composite sintered body. The composite sintered body contains aluminum oxide and silicon carbide particles, and the silicon carbide particles are in contact with each other through a mullite substance, and the volume resistivity value at room temperature of the composite sintered body is 1 × 10 ⁸ Ω ・ c
An electrostatic chuck characterized in that it is not less than m and not more than 1 × 10 ¹⁵ Ω · cm. 2. The electrostatic chuck according to claim 1, wherein the content of carbon silicon in the composite sintered body is 5% by weight or more and 30% by weight or less. 3. The mullite material in the composite sintered body comprises:
3. The electrostatic chuck according to claim 1, which is present on the surface of the silicon carbide particles as an oxide having a thickness of 0.1 μm or less. 4. The average particle size of the composite sintered body is 0.5.
7. A sintered body of a mixed powder of a silicon carbide powder having an oxide film having a thickness of 0.05 μm or less and a surface layer having a thickness of 0.05 μm or less and an aluminum oxide powder in a non-oxidizing atmosphere. The electrostatic chuck according to any one of claims 1 to 3. 5. The electrostatic chuck according to claim 1, wherein the silicon carbide particles in the composite sintered body have an average particle diameter of 1 μm or less.