JP2001048682A - Production of glassy carbon material coated with silicon carbide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glassy carbon material coated with an SiC-film which is suitably used as a heat-resistant member such as a member of a semiconductor production device used under the atmosphere of high temp. and high purity. SOLUTION: In a method for providing an SiC-film on the surface of a substrate made of a glassy carbon material by thermally decomposing a source gas in a gaseous phase by a CVD method, the temp. at the gaseous phase thermal decomposition for coating the SiC-film by depositing SiC on the surface of the substrate is controlled in such a manner that the temp. is gradually raised from the initial film forming process to the final film forming process and is then kept at the temp. of the gaseous phase thermal decomposition in the final film forming process for a prescribed time. Concretely, the gaseous phase thermal decomposition temp. is set and controlled to be in the range of 1,000 to 1,200 deg.C in the initial film forming process and the temp. is further set and controlled to be in the range of 1,200 too 1,700 deg.C in the final film forming process, and the temp. difference between the initial film forming process and the final film forming process is controlled to 100 to 700 deg.C, and the temp. raising rate is controlled to 20 deg.C/min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glassy carbon material coated with a SiC film, which is suitably used as a heat-resistant member used in a high-temperature, high-purity atmosphere, including members of a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, a uniform and dense SiC film is formed on a surface of a carbonaceous material by CVD in order to impart oxidation resistance to the carbonaceous material. A heat-resistant material having a SiC film formed thereon by a CVD method is useful in a wide range of application fields. In addition, SiC
Since the formation of the coating can prevent the volatilization of impurities in the carbon base material, it is useful as a member of a semiconductor manufacturing apparatus requiring high purity.

[0003] However, when used as a member of a semiconductor manufacturing apparatus that repeatedly repeats heating and cooling by rapid heating and rapid cooling, the difference in the coefficient of thermal expansion between the graphite base material and the SiC film is large. Cracks are likely to occur due to the difference, and there is a problem that the SiC coating peels off from the cracks.

A protective tube for a thermocouple, which is one of the members of a semiconductor manufacturing apparatus, is made of a graphite or SiC sintered body having a base material coated with high-purity SiC. However, when repeatedly subjected to thermal cycles of heating and cooling, cracks and peels occur in the SiC layer, exposing the base material surface and diffusing impurities in the base material, thereby contaminating the inside of the system. There is.

[0005]

On the other hand, a glassy carbon material has a coefficient of thermal expansion closer to that of SiC as compared with graphite, and thus has the advantage that cracks due to thermal cycles are less likely to occur. However, since the glassy carbon material has a smooth and dense surface, the glassy carbon material has a problem that adhesion to the SiC film is weak.

Accordingly, the present inventors have conducted intensive studies on a method of depositing a SiC film on a substrate surface by a CVD method using a glassy carbon material as a substrate. It has been found that by setting and controlling the temperature, the adhesion is strong and the SiC film can be formed and adhered firmly.

The present invention has been developed based on this finding, and its object is to provide a member of a semiconductor manufacturing apparatus, for example, a thermocouple protective tube, a liner tube,
S useful as a heat-resistant member for various heat treatments used in semiconductor manufacturing such as process tubes and wafer boats
An object of the present invention is to provide a method for producing a glassy carbon material having an iC film.

[0008]

According to the present invention, there is provided a method for producing a glassy carbon material having a SiC film coated thereon, the method comprising: In the method of decomposing and depositing a SiC film on a substrate surface, the vapor phase thermal decomposition temperature for depositing SiC on the substrate surface and depositing the SiC film is gradually increased from the initial film forming process to the final film forming process. It is characterized in that it is heated and maintained at a vapor phase pyrolysis temperature in a final film forming process for a predetermined time.

More specifically, the gas phase pyrolysis temperature in the initial film formation process is set to 1000 to 1200 ° C., the gas phase pyrolysis temperature in the final film formation process is set to 1200 to 1700 ° C. The temperature is controlled to a high temperature of 700 ° C. The rate of temperature rise from the initial film forming process to the final film forming process is set and controlled to 20 ° C./min or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A glassy carbon material as a base material is obtained by molding and hardening a thermosetting resin such as a phenol-based, furan-based, or polyimide-based resin, and then heating to a temperature of 800 ° C. or more in a non-oxidizing atmosphere. The carbonaceous material is a carbon material having a three-dimensional network structure of a macroscopically non-porous structure obtained by calcining and carbonizing and having a vitreous dense structure. Compared with ordinary carbon materials such as graphite, chemical stability, gas impermeability, surface smoothness,
There is a feature that is excellent in abrasion resistance and the like.

The deposition of the SiC film by the CVD method involves setting a glassy carbon substrate in a reaction chamber of a CVD apparatus, heating the raw material gas, and thermally decomposing the source gas in a gas phase to deposit SiC on the surface of the substrate. Is performed by a method of depositing a SiC film. The source gas contains Si and C atoms in one molecule, for example, trichloromethylsilane (CH ₃ SiCl ₃ ),
A halogenated organosilicon compound such as dichloromethylsilane (CH ₃ SiHCl ₂ ) or trichlorophenylsilane (C ₆ H ₅ SiCl ₃ ) is used. Or carbon tetrachloride
SiC is deposited by sending a silicon compound such as (SiCl ₄ ) and a carbon compound such as methane (CH ₄ ) into a reaction chamber together with a carrier gas such as hydrogen or argon gas to cause a gas phase reaction, thereby depositing SiC. Is to be adhered to.

According to the present invention, this SiC is vapor-phase deposited to form S
characterized in that the thermal decomposition temperature at the time of depositing the iC film is gradually increased from the initial film formation process to the final film formation process, and is maintained at the gas phase thermal decomposition temperature in the final film formation process for a predetermined time, Specifically, the gas phase thermal decomposition temperature is set to 1 in the initial film forming process.
000-1200 ° C, and 1 in the final film formation process.
It is set and controlled at 200 to 1700 ° C. In addition,
The initial film formation step is a step in which a glassy carbon substrate is set in a reaction chamber of a CVD apparatus, heated to a predetermined temperature, and then a raw material gas is fed to cause a gas phase pyrolysis reaction. The film process refers to a process in which the pyrolysis temperature is gradually increased from the initial film formation process, and is maintained for a predetermined time after reaching the set temperature to terminate the gas phase pyrolysis reaction. Also,
The gas phase pyrolysis temperature in the final film formation process is 1
It is necessary to set the temperature higher by 00 to 700 ° C.

If the temperature in the initial film forming process is lower than 1000 ° C., free Si which is a starting point of peeling of the SiC film remains in the film, and if the temperature exceeds 1200 ° C., adhesion of the deposited SiC film to the substrate surface. And the SiC film cannot be firmly adhered to the substrate surface. On the other hand, if the temperature in the final film forming step is lower than 1200 ° C., the corrosion resistance of the SiC film is not sufficient, and if it is higher than 1700 ° C., the thickness of the SiC film becomes uneven and the dispersion becomes large. That is, the present invention sets and controls the gas phase pyrolysis temperature in the initial film formation process and the final film formation process to a specific temperature range, thereby firmly depositing the SiC film on the substrate surface of the glassy carbon material. It is. It should be noted that the time for maintaining the predetermined gas phase pyrolysis temperature in the final film forming process is appropriately set according to the desired thickness of the SiC film.

Further, the rate of temperature rise from the initial film forming process to the final film forming process is set to 20 ° C./min or less. If the heating rate is high, the denseness of the vapor-deposited SiC film decreases, and the adhesion to the substrate surface also decreases. That is, the heating rate is 20 ° C.
When the heating rate exceeds 20 / min, the thermal shock resistance of the deposited SiC film is reduced, so that cracks are likely to occur due to thermal cycling, and the corrosion resistance of the SiC film is also reduced. The settings are controlled as follows.

[0015]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples.

Example 1 A phenol resin precondensate prepared from phenol and formalin produced by distillation under reduced pressure was poured into a mold.
After degassing under a reduced pressure of 10 Torr for 3 hours, it was placed in an electric oven at 80 ° C. and left standing for 24 hours to form a cylindrical tube with an inner diameter of 10 mmφ, an outer diameter of 15 mmφ and a length of 1500 mm. Next, the mold was taken out of the mold and heated at a rate of 10 ° C./hour for 1 hour.
The temperature was raised to 80 ° C., and held for 24 hours to cure. This cured resin molded product was put in an electric furnace while being sandwiched by a high-purity graphite tube with an inner diameter of 15 mmφ and the surroundings were 100 ppm in total ash.
Less than 1000 graphite powder at a rate of 2 ° C./hour.
℃, and calcined and carbonized. Furthermore, it is transferred to a vacuum furnace in which atmosphere can be replaced, and chlorine / helium (molar ratio: 5/9
5) While supplying the purified gas at a rate of 5 L / min, the temperature was raised to 2000 ° C. to perform a high-purity treatment, and
A high-purity glassy carbon material having a cylindrical shape with a bottom having a diameter of 15 mm, an outer diameter of 15 mm and a length of 1500 mm was produced.

The glassy carbon material was set in a reaction chamber (volume: 570 l) of a CVD reactor, and the system was heated after purging the system with hydrogen gas. After reaching a temperature of 1100 ° C., a mixed gas (concentration of trichloromethylsilane: CH ₃ SiCl ₃ / H ₂ = 7.5 Vol%) using trichloromethylsilane as a raw material gas and hydrogen as a carrier gas is 240 liter / min. 10 minutes after passing at a flow rate of 10 ° C /
At a heating rate of 1500 min.
Holding for 0 minutes, the SiC film was applied.

Examples 2 to 9 and Comparative Examples 1 to 5 High-purity glassy carbonaceous materials produced in the same manner as in Example 1 were subjected to the vapor phase pyrolysis temperature and the temperature increase during the initial film formation process and the final film formation process. By changing the speed and the holding time, SiC films having different thicknesses were deposited.

A thermal shock test and a corrosion resistance test were performed on the glassy carbon material coated with the SiC film thus manufactured by the following method. The results obtained are shown in Table 1 in comparison with the conditions for depositing the SiC film. Indicated. Thermal shock test: Heating using an electric furnace held in an air atmosphere, and raising and lowering the temperature from 500 ° C. to 1200 ° C. were repeated 20 times, and the crack generation state and appearance inspection of the SiC film by this thermal cycle test were performed. Was done. Corrosion resistance test: In a hydrogen chloride gas atmosphere at a temperature of 1200 ° C (H
(Cl; 100%) was measured for 15 hours, and the weight loss rate was calculated.

[0020]

[Table 1]

From the results shown in Table 1, it can be seen that in Examples 1 to 9 satisfying the manufacturing requirements of the present invention, since the SiC film is firmly adhered to the glassy carbon substrate surface, cracks are generated even in the thermal shock test. No appearance was observed, the appearance was good, and the corrosion resistance test showed that the weight loss rate was small. On the other hand, in Comparative Examples 1 to 5 in which the gas phase pyrolysis temperature conditions deviate from the requirements of the present invention, the thermal shock resistance and the corrosion resistance are inferior, and the temperature in the initial film formation process is low, and the temperature in the final film formation process is low. In Comparative Example 2, the corrosion resistance was significantly reduced, and in Comparative Example 3 in which the rate of temperature rise was large, the occurrence of cracks in the thermal shock test was increased. In Comparative Example 4, in which the thermal decomposition temperature in the final film formation process was high, SiC was used. It was recognized that the thickness of the film was uneven, and the dispersion was large.

[0022]

As described above, according to the method for producing a glassy carbon material with a SiC film deposited thereon according to the present invention, S
The vapor phase pyrolysis temperature at the time of depositing the iC film is set to a temperature range of 1000 to 1200 ° C. in the initial stage, 1200 to 1700 ° C. in the final stage, and the temperature difference between the initial stage and the final stage is set to 100 ° C. By setting the temperature in a temperature range of ~ 700 ° C and gradually increasing the temperature at a rate of 20 ° C / min or less from the initial stage to the final stage, a SiC film having excellent corrosion resistance is firmly formed on the glassy carbon substrate surface. Adhesion is possible, and peeling due to thermal cycling is also reduced. In addition, SiC
Variations in film thickness are suppressed without the film being deposited in a patchy manner. Therefore, it is extremely useful as a method for manufacturing members for various heat treatments used for manufacturing semiconductors such as thermocouple protection tubes, liner tubes, process tubes, and wafer boats.

Claims (3)

[Claims] In a method of depositing a SiC film on a substrate surface by vapor-phase pyrolyzing a raw material gas by a CVD method using a glassy carbon material as a substrate, depositing SiC on the substrate surface and coating the SiC film on the substrate surface. Characterized in that the temperature of the vapor phase pyrolysis to be deposited is gradually increased from the initial film formation process to the final film formation process, and is maintained at the gas phase pyrolysis temperature in the final film formation process for a predetermined time. Method for producing carbonaceous material. 2. The gas phase thermal decomposition temperature in the initial film formation process is 100.
2. The method according to claim 1, wherein the temperature is from 0 to 1200 ° C., the gas phase thermal decomposition temperature in the final film forming process is from 1200 to 1700 ° C., and the temperature is set to 100 to 700 ° C. higher than the initial film forming process. A method for producing a glassy carbon material coated with a SiC film. 3. The method according to claim 1, wherein the rate of temperature rise from the initial film forming step to the final film forming step is 20 ° C./min or less.
A method for producing a glassy carbon material coated with an iC film.