JP2000281430A - Black SiO2 corrosion-resistant member and method of manufacturing the same - Google Patents

Abstract

[Problem] To provide a dense black SiO ₂ sintered body having high purity black which has excellent corrosion resistance even when exposed to corrosive gas or the like and can improve the energy efficiency of heat treatment. obtain. The total amount of metals other than Si is 0.1% by weight or less, the hydroxyl group content is 20 ppm or less, and the average particle size is 5 μm.
m below the SiO ₂ powder, by adding an organic binder and molded into a predetermined shape, after generating the carbon to decompose the organic binding agent at a temperature of 250 to 450 ° C. C. in an oxidizing atmosphere, a non-oxidizing atmosphere Baked at 1100 to 1600 ° C in a medium having a carbon content of 0.05 to 1.0% by weight and a density of 2.03 to 2.21.
g / cm ³ , a hydroxyl group content of 5 ppm or less, a total amount of metals other than Si of 0.5% by weight or less, and a wavelength of 200
A corrosion-resistant member made of an amorphous sintered body having a linear transmittance of １６16000 nm and a linear transmittance of 1% or less is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to, as a corrosion resistant member for exposed heat treatment corrosive gas or the like, in particular to a semiconductor and a field a useful high purity black SiO ₂ quality corrosion resistant member and a manufacturing method thereof LCD manufacturing is there.

[0002]

2. Description of the Related Art Conventionally, in a process of forming a highly integrated circuit such as a semiconductor device or a liquid crystal, a quartz glass member that can relatively easily produce a high-purity member has been frequently used because impurities have an influence on device characteristics. However, in particular, in a heat treatment process such as infrared heating, energy loss in using a transparent quartz glass member has been attracting attention in recent years, and a black high-purity material that does not transmit infrared light has been demanded.

Conventionally, blackening of the quartz glass, V ₂ O ₅ or the like in a quartz glass, which is produced by adding transition metal oxide, such as Va metal or Fe ₂ O ₃ as a coloring agent (JP See JP-A-54-157121, JP-A-7-196335, JP-A-4-254433, and the like. However, such materials tend to be discolored by high-temperature heat histories and contain relatively large amounts of coloring metals that may adversely affect semiconductors. Was not preferred.

On the other hand, there has been proposed a method of uniformly blackening quartz glass by adding silicon carbide or carbon without adding an impurity metal (Japanese Patent Laid-Open No. 5-170).
477, JP-A-5-306142 and JP-A-6-122533).

Japanese Patent Application Laid-Open No. 5-306142 proposes that a carbon component is added to a quartz glass powder and then calcined to produce a 1 to 5% by weight carbon-containing black quartz glass.

Further, a carbon-containing quartz glass obtained by calcining a mixture of a carbon powder and a silica powder is also disclosed in JP-A-3-279209.
Has been proposed.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No.
When silicon carbide is added as disclosed in Japanese Patent No. 70477, the densification is inhibited and a low-density porous body is obtained.
It was necessary to densify using a hot isostatic press or the like.
Further, since the color tone changes during the vitrification process, it has been difficult to obtain a stable material.

Although the above-mentioned carbon-containing black quartz glass is excellent in heat resistance and oxidation resistance, it is not sufficient in terms of corrosion resistance to corrosive gases and the like. When used in an apparatus, there has been a problem that the carbon-containing black quartz glass is corroded by the corrosive gas, and particles are generated to adversely affect the system.

In particular, quartz glass containing more than 1% by weight of carbon as disclosed in Japanese Patent Application Laid-Open No. 5-306142 has a problem that when it comes into contact with a corrosive gas, it tends to be corrosive. .

The present invention provides a metal impurity which has excellent corrosion resistance even when exposed to a corrosive gas or the like, exhibits a high-purity black color which can improve the energy efficiency of heat treatment, and has a significant effect on a semiconductor manufacturing process. It is intended to provide a dense black SiO ₂ sintered body which does not contain OH and has a reduced content of a hydroxyl group which deteriorates heat resistance and plasma characteristics, and a production method for stably producing the same.

[0011]

The black SiO ₂ corrosion-resistant member of the present invention has a carbon content of 0.05 to 1.0% by weight.
The density is 2.03 to 2.21 g / cm ³ , the hydroxyl group content is 5 ppm or less, the total amount of metals other than Si is 0.5% by weight or less, and the linear transmittance at a wavelength of 200 to 16000 nm is 1% or less. It is characterized by being made of an amorphous sintered body.

The method for producing a black SiO ₂ -based corrosion-resistant member of the present invention is characterized in that the total amount of metals other than Si is 0.1% by weight or less, the hydroxyl group content is 20 ppm or less, and the average particle size is 5 μm.
m or less of an SiO ₂ powder, an organic binder is added thereto, and the mixture is molded into a predetermined shape.
After heat treatment at a temperature of 0 ° C. to decompose the organic binder to form carbon, the carbon is produced in a non-oxidizing atmosphere.
It is characterized by firing at 0 ° C. to obtain a sintered body having a density of 2.03 to 2.21 g / cm ³ and a carbon content of 0.05 to 1.0% by weight.

[0013]

The black SiO ₂ corrosion-resistant member of the present invention has a wavelength of 2
It has a linear transmittance of 1% or less (substantially below the detection limit of a measuring device) in a wide wavelength range from the far-infrared region from 00 nm to 16000 nm. In this case, it is effective for improving the thermal efficiency as compared with the transparent quartz glass member. In addition, since it is substantially composed of only an amorphous phase, at least 1400
Characteristics can be maintained without crystallization or discoloration up to a temperature of ° C.

Further, since the hydroxyl group content is 5 ppm or less, it exhibits high corrosion resistance to corrosive gases, maintains high strength against high-temperature heat histories in a heat treatment process, and has a high level in a plasma treatment process. The release of hydroxyl groups does not adversely affect the plasma.

In producing a black SiO ₂ sintered body having the above characteristics, the total amount of metals other than Si is 0.1% by weight.
Hereinafter, the content of hydroxyl groups is 20 ppm or less, and the average particle size is 5 μm.
m or less of an SiO ₂ powder, an organic binder is added thereto, and the mixture is molded into a predetermined shape.
By performing a heat treatment at a temperature of 0 ° C. to decompose the organic binder to generate carbon, the carbon can be converted into a state in which the carbon is easily dissolved in the SiO ₂ glass network,
Then, in a vacuum or non-oxidizing atmosphere, 1100-1
By baking at 600 ° C., a member having the above excellent characteristics can be stably manufactured.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The black SiO ₂ corrosion-resistant member of the present invention is in contact with a corrosive gas typified by a halogen-containing gas such as HF, HC1, ClF _3, etc. It is useful as a forming process, particularly as a member for bell jars, rings, furnace tubes and the like of heat treatment apparatuses such as lamp annealing, CVD, and diffusion furnaces.
Since the linear transmittance at 0 to 16000 nm is 1% or less, it is possible to use energy that has been emitted to the outside as light in transparent quartz glass, which is effective in improving thermal efficiency.

The black SiO ₂ corrosion-resistant member of the present invention contains 0.05 to 1.0% by weight of carbon, especially 0.2 to
It is a sintered body containing 0.8% by weight and the balance substantially consisting of SiO ₂ . This carbon is a component that blackens the sintered body, but if the carbon content is less than 0.05% by weight, color unevenness occurs and it is difficult to exhibit a uniform black color. Is more than 1% and is used as a member, there is no effect on the improvement of thermal efficiency.

On the other hand, if the carbon content exceeds 1.0% by weight, the sinterability is rapidly reduced, and a predetermined density cannot be obtained, resulting in a porous body. Further, even if the firing temperature is increased, a gas is generated by the reaction between carbon and silica, so that a foam is formed and the strength is greatly reduced.

The sintered body constituting the corrosion resistant member has a density of 2.03 to 2.21 g / cm ³ , especially 2.1.
0 to 2.20 g / cm ³ . This density is 2.03g
If it is lower than / cm ^{3, the} strength decreases due to residual pores and the light transmittance increases. If it is higher than 2.21 g / cm ³ , SiO ₂ is crystallized or carbon is converted to SiC, resulting in poor heat resistance. descend.

Further, the SiO ₂ sintered body according to the present invention is substantially composed of only amorphous. SiO ₂
In the + C system, a crystal phase such as quartz, cristobalite, and silicon carbide is easily formed.
By known crystal phase detection methods such as X-ray diffraction measurement,
These crystal phases are not detected. This is because, when the high-temperature heat history is repeated in the presence of the crystal phase, the life of the member is shortened due to the growth of the crystal phase or the occurrence of cracks due to the difference in thermal expansion between the amorphous phase and the crystal phase. It is.

The existence form of carbon contained in the SiO ₂ sintered body in the present invention may be such that the silicon carbide crystal phase is not confirmed as described above, and the carbon content may be substantially the same depending on the production method. In the sintered body of the present invention, a binder that can be a carbon source uniformly dispersed between fine SiO ₂ particles is decomposed by heat treatment and taken into a glass network because the body becomes a transparent body or a white body having a crystalline phase. Rarely, it is considered that the solid solution was uniformly solidified and blackened during the firing process.

It is important that the hydroxyl group content is 5 ppm or less, especially 1 ppm or less. This hydroxyl group
When it comes into contact with a corrosive gas, it reacts with the gas to cut the glass network, and further promotes the reaction, thereby significantly reducing the corrosion resistance. Further, there is a problem that the heat resistance at high temperature is low and the member is deformed by repeating the high temperature heat history. Furthermore, when a member is used in plasma, the corrosion resistance of the member surface to the plasma is reduced, and the release of hydroxyl groups from the member adversely affects the plasma state. Is more likely to occur.

The hydroxyl group content C (ppm)
Can be calculated by measuring the transmittance of infrared rays having wavelengths of 2.60 μm and 2.73 μm and calculating the following equation 1 based on the Lambert-Beer equation.

[0024]

(Equation 1)

In consideration of prevention of impurities from being mixed during the production of semiconductor elements, the content of metals other than Si is 0.5% by weight or less, particularly 0.3% by weight or less and 0.1% by weight or less. It is necessary.

In addition, corrosion resistance upon contact with corrosive gas
In order to improve the property, the above SiO _TwoPart consisting of sintered body
The average surface roughness Ra of the material surface is 1 μm or less, especially 0.5 μm
m or less, more preferably 0.1 μm or less.
No. This is due to the contact area with corrosive gas when the surface roughness is rough.
Is increased and the progress of corrosion is accelerated.

Next, as a method for producing the above-mentioned black SiO ₂ corrosion-resistant member, the total amount of metals other than Si as a raw material powder is 0.1% by weight or less, particularly 0.05% by weight or less.
High-purity SiO ₂ having a hydroxyl content of 20 ppm or less, particularly 15 ppm or less, and an average particle size of 5 μm or less, particularly 1 μm or less.
Prepare powder. In particular, this SiO ₂ powder is desirably a synthetic raw material rather than a natural raw material.

If the total amount of metals other than Si in the SiO ₂ raw material powder is more than 0.1% by weight, the total amount of metals other than Si in the sintered body may be reduced to 0.5% by weight or less. It becomes difficult, and in addition to mixing of impurities from the member into the semiconductor element and particle formation of the impurities, crystallization using the impurity metal as a crystal nucleus in the sintered body progresses and whitening occurs,
This is because problems such as a decrease in heat resistance and deterioration due to heat history occur, and a target amorphous sintered body cannot be obtained.

If the average particle size of the raw material is larger than 5 μm, the temperature required for sintering rises to near the melting point, the powder is melted, gas is generated by the reaction between carbon and silica, and a foam is formed. Therefore, a desired sintered body cannot be obtained. Therefore, by using a raw material powder having an average particle size of 5 μm or less, a dense sintered body can be manufactured without melting at a temperature lower than the melting point by 100 ° C. or more.

The raw material powder has a hydroxyl group content of 20 pp.
If m is exceeded, it becomes difficult to reduce the hydroxyl groups remaining in the sintered body to 5 ppm or less. Since it is difficult to remove hydroxyl groups in the raw material by post-synthesis treatment, it is necessary to minimize the amount of hydroxyl groups in the raw material in order to obtain a sintered body having a low hydroxyl group content. In order to reduce the hydroxyl group content, for example, a method of reacting an oxidizable silicon compound with oxygen gas by laser heating (Japanese Patent Publication No. 53-2443)
No. 5), a method of performing a heat treatment in a hydrogen atmosphere (Japanese Unexamined Patent Publication No.
4859) or the like.

As a method of synthesizing the raw materials, any method may be used as long as the resulting SiO ₂ powder has the above-mentioned characteristics, but from the viewpoint of obtaining a fine powder having a small hydroxyl group content, , A high-temperature hydrolysis method of SiCl ₄ , a plasma method in which oxygen or a mixture of oxygen and Ar is reacted in plasma, and a method of burning high-purity metallic Si powder in an oxidizing gas flow. Since the sol-gel method using silicate alkoxide as a raw material often contains a large amount of chemically adsorbed water, it cannot be said that it is preferable as a raw material for producing the sintered body of the present invention.

Next, an organic binder such as wax or polyvinyl alcohol which can serve as a carbon source is added to the powder together with a solvent such as isopropyl alcohol or water, and mixed uniformly. If desired, crushing and pulverization can be performed separately or simultaneously.

Thereafter, the mixed raw material is formed into a predetermined shape. As the molding method, an appropriate molding method may be selected according to the shape of the target member. Specifically, any of dry molding methods such as mold press molding and isotropic isostatic press molding, and wet molding methods such as cast molding, extrusion molding and injection molding may be used.

When crushing, pulverizing, etc. are performed by a wet method,
Although the solvent is not particularly limited, for example, the use of water does not affect the hydroxyl group content of the sintered body at all.

The thus formed SiO ₂ molded body is subjected to a heat treatment at a temperature of 250 to 450 ° C. in an oxidizing atmosphere to perform a degreasing and decomposition treatment. At this time,
When the treatment is performed in a vacuum or non-oxidizing atmosphere, the binder evaporates without being decomposed, and the amount of residual carbon required for blackening cannot be obtained. When the heat treatment temperature is lower than 250 ° C., the binder remaining undecomposed is degreased without decomposition during firing, and the sintered body is not uniformly blackened. 450 ° C
Is exceeded, the oxidation of carbon becomes remarkable, and the carbon content becomes 0.0
Since it is less than 5% by weight, a black sintered body cannot be obtained.

Further, since the carbon decomposed and remaining at this stage hardly changes quantitatively even by firing, the heat treatment temperature is within the temperature range specified in the present invention, depending on the decomposition temperature of the added binder and the like. The carbon content may be appropriately selected and the necessary amount of carbon may be adjusted.

The SiO ₂ molded body thus treated is placed in a non-oxidizing atmosphere such as vacuum or nitrogen gas, argon gas, or a mixed gas of hydrogen and argon, etc.
By baking at a temperature in the range of 600 ° C., more preferably 1250 to 1450 ° C., carbon uniformly dispersed in the compact during the sintering process is taken into the glass network without reacting and is dense and uniform. Blackened SiO ₂
A member made of a sintered body can be obtained.

In order to reduce the hydroxyl group content in the sintered body, it is preferable to perform vacuum firing, but a hydroxyl group content of 5 ppm or less can be achieved even in the non-oxidizing atmosphere. The degree of vacuum during vacuum firing is desirably 0.2 Torr or less.

On the other hand, in the case of firing in an oxidizing atmosphere such as air, blackening cannot be achieved for the same reason as in the previous heat treatment step, and the hydroxyl content in the sintered body is 10%.
The content is 0 ppm or more, so that a target black SiO ₂ sintered body cannot be produced.

When the firing temperature is lower than 1100 ° C.,
Since the sinterability is reduced, a dense sintered body cannot be obtained, and since the solid solution of carbon is insufficient, the sintered body has a white, gray or uneven color. Further, if the temperature is higher than 1600 ° C., the raw material particle diameter is so fine that melting starts, not only the whole becomes vitrified and the shape cannot be maintained, but also a gas is generated by the reaction of carbon and SiO ₂ , and a large amount of bubbles And the carbon required for blackening is consumed, so that the desired black SiO
_{2 A} sintered body cannot be obtained.

The black SiO ₂ sintered body thus obtained can be used as it is, or a member having a desired shape can be formed by grinding or the like, depending on the shape of the member to be applied.
In addition, although it is possible to clean and use the member as it is depending on the purpose of the member that comes into contact with the corrosive gas, it can be processed into a desired shape by grinding and polishing as appropriate.

[0042]

EXAMPLE The amount of metal other than Si produced by burning fine metal Si powder in an oxygen stream is 0.01 to 0.2% by weight.
Hydroxyl content 10-25 ppm, average particle size 0.2-15
A sintered body was prepared using the μm SiO ₂ raw material powder, and the physical properties were evaluated.

First, the raw material powder was wet-crushed with a ball mill using ultrapure water as a solvent, and various compounds shown in Table 1 were added as an organic binder to prepare a slurry. High-purity SiO ₂ is used as a medium during wet crushing.
A ball was used. The raw material powder obtained by granulating this slurry is molded by a mold press under a load of 0.8 ton / cm ² ,
This was degreased under the conditions shown in Table 1.

The degreased body thus produced was fired under the firing conditions shown in Table 1, and the following characteristics of the obtained SiO ₂ sintered body were measured.

For evaluation of the characteristics, the sintered body density was measured by measuring the bulk density by the Archimedes method. The color tone of the sintered body was visually determined by cutting out the vicinity of the center of the sintered body and processing it to a thickness of 1 mm. The linear transmittance of light was measured at a wavelength of 200 to 16000 nm from a material processed to a thickness of 1 mm, and the maximum value was shown. The hydroxyl content is
IR (infrared absorption spectrum) was measured and calculated based on the above equation (1).

The crystal phase of the sintered body was measured by a powder X-ray diffraction method by cutting out the center of the sintered body and pulverizing it. Regarding the material strength, a test piece of 4 mm × 3 mm × 50 mm was cut out from the sintered body, and a bending test was performed by a four-point bending test based on JISR1601.

The heat resistance of the sintered body was maintained at 1400 ° C. for 2 hours, and changes in weight, dimensions, color tone, and presence or absence of cracks were evaluated.

Further, for the corrosion resistance, a sintered body having a diameter of 200 mm was prepared, and the surface thereof was made to have an average surface roughness Ra of 0.08.
After being mirror-polished to a thickness of μm, this was exposed to HF plasma at room temperature using a RIE (reactive ion etching) apparatus, and the etching rate was measured.

[0049]

[Table 1]

[0050]

[Table 2]

According to the results shown in Tables 1 and 2, among the samples No. 1 to 10 degreased in the air, the sample No. 8 baked in the air has a carbon component oxidized in the calcination process. Detached,
A transparent sintered body was obtained because the amount of carbon in the sintered body was insufficient. Also, since a large amount of hydroxyl groups remained in the sintered body, the viscosity was lowered at high temperature and the sintered body was deformed.

In Sample No. 9, the degreasing temperature was low, the decomposition of the binder did not proceed, and crystallization occurred with free carbon as a nucleus, resulting in a translucent sintered body. At a high temperature, the fine crystals contained therein grew, and micro-cracks were generated, resulting in partial cloudiness.

Sample No. 10 had a high degreasing temperature, and the binder decomposed into carbon reacted with oxygen to be desorbed, resulting in a transparent body having a low carbon content. Sample No. 11 was baked as it was without performing a degreasing treatment, and as a result, the binder was removed without oxidative decomposition during the calcination, resulting in a transparent body.

Samples Nos. 12 and 13 were not in an oxidizing atmosphere, and were melted and desorbed without decomposing the binder during degreasing, resulting in a transparent sintered body having a low carbon content. When these transparent sintered bodies are heat-treated at a high temperature, crystallization proceeds from the surface unless they contain an impurity metal, and they become cloudy and cannot be used.

Of the samples 14 to 17 having different firing temperatures,
Sample No.14 is not densified because the firing temperature is too low, the sample No.17 reacts the SiO ₂ and carbon for the firing temperature is too high to form a SiC crystal becomes dark green, upon further reaction Bubbles were generated inside by the generated gas, and the density was reduced.

When the purity of the raw material was changed, in Sample No. 19, since the amount of metals other than Si was more than 0.1% by weight, the amount of metals other than Si in the sintered body increased, and the sintered body was colored dark brown. At the same time, crystallization occurred with the impurities as nuclei, and at high temperatures, the crystallization proceeded further and became cloudy.

Regarding the hydroxyl group content in the raw material, 20 p
In Sample No. 21 exceeding pm, hydroxyl groups were not completely removed during the firing step and remained, causing deformation at high temperatures.

Regarding the average particle size of the raw materials, it was difficult to densify the sample Nos. 25 and 26 exceeding 5 μm at a temperature at which carbon did not react with SiO ₂ .

Further, in sample No. 28 to which graphite was added as a carbon source, the sintering was hindered because the carbon content exceeded 1%, and further crystallization occurred, so that the desired black SiO ₂ sintered body was not obtained. I couldn't get it. Also, when a binder or the like serving as a carbon source was not added as in Sample No. 29, blackening could not be achieved.

[0060] Samples No.1~7,15,16,18,20,2 contrast, a SiO ₂ sintered body in the present invention
For 2 to 24 and 27, the density is 2.03 to 2.21 g / cm.
^{3. The} linear transmittance was at most 1% at a wavelength of 200 to 16000 nm. Further, since the hydroxyl group content is 5 ppm or less, and it has no crystal phase, it has heat resistance so as not to cause deformation and discoloration even when heat-treated at 1400 ° C., and has an excellent etching rate of 50 nm / min or less. It showed corrosion resistance.

[0061]

As described in detail above, according to the present invention,
A semiconductor manufacturing process that uses a dense sintered body as a corrosion-resistant member that contains no metal impurities, reduces the amount of hydroxyl groups that degrade heat resistance and plasma characteristics, and has high corrosion resistance even in contact with corrosive gases. In this case, it is possible to improve the energy efficiency of the heat treatment by prolonging the life of the member and without mixing metal impurities having a significant effect.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Hamada 1-1, Yamashita-cho, Kokubu-shi, Kagoshima F-term in the Kokubu Plant of Kyocera Corporation 4G030 AA37 AA60 BA33 GA11 GA27 PA12

Claims (2)

[Claims] (1) a carbon content of 0.05 to 1.0% by weight, a density of 2.03 to 2.21 g / cm ³ , and a hydroxyl content of 5 to 5%;
ppm or less, a total amount of metals other than Si is 0.5% by weight or less, and an amorphous sintered body having a linear transmittance of 1% or less at a wavelength of 200 to 16000 nm is a black SiO ₂ material. Corrosion resistant material. 2. The total amount of metals other than Si is 0.1% by weight or less, the hydroxyl group content is 20 ppm or less, and the average particle size is 5 μm.
m or less of an SiO ₂ powder, an organic binder is added thereto, and the mixture is molded into a predetermined shape.
After heat treatment at a temperature of 0 ° C. to decompose the organic binder to form carbon, the carbon is produced in a non-oxidizing atmosphere.
Calcined at 0 ° C., a density 2.03~2.21g / cm ^3, the manufacturing method of black SiO ₂ anti-corrosion member, characterized in that to obtain a carbon content from 0.05 to 1.0% by weight of the sintered body.