JP2001335366A - Glassy carbon tube precursor and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal molding method for efficiently manufacturing thermosetting resin moldings (glassy carbon tube precursors) having neither bubbles nor cracks, by performing the curing rapidly and efficiently at the time of the centrifugal molding, and to provide a manufacturing method for a glassy carbon tube with a high quality in high productivity. SOLUTION: A mold having an increased inner surface area by roughing is used. The raw materials containing a thermosetting resin are centrifugally molded to produce the glassy carbon tube precursor and further to produce the glassy carbon tube by carbonizing the precursor.

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 thermosetting resin tube by centrifugal molding using a thermosetting resin as a raw material, and carbonizing the tube to produce a glassy carbon tube. When manufacturing a thermosetting resin tube which is a precursor of a glassy carbon tube by a centrifugal molding method, a device is devised so that the molding can be performed efficiently in a short time while suppressing defects during the centrifugal molding as much as possible. It relates to the production method. The glassy carbon tube produced by this method can be suitably used particularly as an inner tube of a CVD apparatus for semiconductor production.

[0002]

2. Description of the Related Art Quartz glass is generally used for members requiring heat resistance, gas impermeability, corrosion resistance and the like, such as an inner tube of a CVD apparatus for semiconductor production. However, quartz glass has a problem that it is easily corroded by a fluorine-based gas or a mixed solution of nitric acid and hydrofluoric acid for cleaning, and its life is extremely short.

Therefore, glassy carbon is expected as a material to replace quartz glass. Glassy carbon is a carbon material that is usually obtained by using a thermosetting resin such as a phenolic resin or a furan resin as a precursor and carbonizing the same at a high temperature range of about 1000 ° C. or higher. It has excellent heat resistance, mechanical strength and hardness equal to those of quartz glass, extremely low gas permeability, and extremely excellent corrosion resistance to the above-mentioned chemicals.

[0004] For these reasons, materials containing glassy carbon as a main component have been used in various fields as structural members requiring high heat resistance. However, in order to obtain a glassy carbon tube, it is necessary to manufacture a thermosetting resin tube as a precursor thereof. Unlike a thermoplastic resin, a thermosetting resin has a low viscosity in a molten state and an extremely long holding time. Therefore, it is difficult to obtain a tubular molded body by a method such as extrusion molding, compression molding, injection molding, or the like in which a thermoplastic resin is used alone with a thermosetting resin alone. In particular, the inner tube used in the CVD apparatus has, for example, a diameter of about 300 mm, a length of 1000 mm, and a thickness of 3 to 5 mm.
It has a cylindrical shape with both ends open, and it is difficult to form such a shape using only a thermosetting resin.

In order to manufacture a large-diameter tube, a method of mixing a thermosetting resin with an inorganic filler such as magnesia, talc, mica, or the like has been adopted, and if such a composite material is used. By extrusion molding, it is possible to form a high-strength tube suitable as an electric resistance welded tube or the like. Also,
When a liquid thermosetting resin is impregnated into a non-woven carbon fiber cloth and compression-molded, a carbon fiber-thermosetting resin composite having high strength and elastic modulus can be obtained. That is, when used as a thermosetting resin molded body without being carbonized, the composite of the filler and the reinforcing material is preferable because the physical properties of the molded body can be enhanced and the amount of expensive resin used can be saved.

However, in order to obtain a glassy carbon molded body, it is necessary to carbonize a previously molded thermosetting resin molded body in a high-temperature inert atmosphere. The following problems may occur. That is, since a thermosetting resin molded article generally shrinks by more than 10% with the release of hydrogen and oxygen during carbonization, when a thermosetting resin tube with a filler is carbonized, a glassy carbon part is formed. Then, cracks occur at the interface of the filler portion where the dimensional change is small, and as a result, gas impermeability and corrosion resistance, which are the characteristics of glassy carbon, are significantly impaired.
For example, in the above-described carbon fiber-thermosetting resin composite (so-called precursor of carbon-carbon composite material), a member obtained by carbonizing the composite contains many fine cracks and voids. The impregnation and carbonization had to be repeated several times.

Further, the filler component has poor corrosion resistance as compared with glassy carbon, and there is a possibility that impurities derived from the filler itself may scatter in the CVD apparatus and contaminate the CVD film. It lacks suitability for inner tubes and the like.

[0008] For these reasons, there is a strong demand for the development of a glassy carbon tube containing no filler, preferably having a glassy carbon content of 95% or more, more preferably substantially only glassy carbon. For example, it is desired to develop a method for producing a glassy carbon tube that can be suitably used as an inner tube or the like used in a CVD apparatus.

Accordingly, the present inventors have focused on a thermosetting resin tube containing no filler as a precursor of a glassy carbon tube, and have intensively studied a molding method thereof. As a result, it has been found that it is possible to obtain a tubular thermosetting resin molded article by injection molding or compression molding that has been widely used in the past. However, in order to facilitate release of the thermosetting resin molded article from the mold, it is necessary to taper the inner surface of the pipe at least at an angle of about 0.5 ° or more, preferably about 1 ° or more. It is also found that the size and shape of the glassy carbon tube, which is the final product, become non-uniform due to the change in size and shape caused in the carbonization step, and the difference in inner diameter between both ends exceeds about 1% of the length. This is a defect that cannot be neglected in obtaining an industrially useful tube with high dimensional accuracy. In addition, the injection molding method and the compression molding method are not originally suitable for molding a thermosetting resin molded article, so that the productivity is poor. Further, the precursor of the large-diameter glassy carbon pipe as described above is used. Since an extremely large mold is required to mold a resin tube to be a body, it is extremely difficult to manufacture the resin tube with good productivity and low cost on an industrial scale.

[0010] Under such circumstances, in the production of a glassy carbon tube containing no filler, in order to obtain a tube having a small inner diameter error by compression molding or injection molding, it is necessary to use a taper for demolding. A tube that is so short and thin that it is not necessary to apply it, specifically, a tube having a length of about 60 mm or less and a diameter of about 15 mm or less has been regarded as a limitation in manufacturing technology. And, in order to manufacture a large-diameter and long tube exceeding this, it is necessary to perform taper processing for demolding, and as described above, a difference in inner diameter of the tube exceeding 1% with respect to the length occurs. As described above, it is difficult to extrude a thermosetting resin containing no filler into a tubular shape.

In addition to such a molding method, a centrifugal molding method is known as a method suitable for molding a tubular molded body using a thermosetting resin (JP-A-6-247770,
JP-A-4-149067). However, the methods disclosed in these publications are methods using a resin material with a composite filler, and there is no description suggesting a method using a resin material without a composite filler.
In fact, the present inventors attempted to mold a glassy carbon tube containing no filler using the methods disclosed in these publications, and found that the step of forming a thermosetting resin tube as a precursor thereof was In order to prevent this, extremely long molding and strict temperature control were required, and it was not possible to produce a tube having no void defect with high reproducibility under high productivity. Even if a satisfactory resin tube is obtained, many vacancy defects are generated in the final molded product due to the volatilization of residual solvent and decomposition gas generated in the subsequent carbonization step, resulting in gas insufficiency. A glassy carbon tube excellent in permeability and corrosion resistance could not be obtained.

Further, a reference ("Carbon", 1996, vol.
34, No. 6, p. 789-796), by continuously applying liquid phenolic resin to the outer surface of a rotating metal cylinder in the form of a spray, while removing the solvent and promoting the curing reaction of the resin. Discloses a method for producing a phenol resin tube which is a precursor of glassy carbon. However, the glassy carbon tube disclosed in this document has an inner diameter of one.
It has a small diameter of about 2.7 mm, and the production method of a tube having a diameter larger than that is not disclosed. Also,
When the present inventors conducted additional tests of this method, many factors were strictly determined, such as the resin supply speed and the rotation speed of the cylindrical mold, as well as the temperature for controlling the curing reaction of the resin and the amount of evaporation of the solvent. Even if it was controlled, it was not possible to obtain a resin tube with high dimensional accuracy and uniform thickness.

As described above, various studies have been made on the method of producing a glassy carbon tube. However, there are many techniques for producing a thermosetting resin tube as a precursor of the glassy carbon tube, particularly a large-diameter tube. The problem remains, after all, heat resistance, gas impermeability, corrosion resistance,
A glassy carbon tube excellent in durability and the like, particularly an inner tube of a CVD apparatus for semiconductor production with less contamination has not been provided.

[0014]

The present invention is based on the above circumstances.
Paying special attention, especially the inner tube of CVD equipment for semiconductor manufacturing
Low-contamination vitreous coal with excellent performance
We have been conducting further research for the production of raw tubes.
One of the results is the use of raw material precursors.
10% curing degree at 115 ° C as thermosetting resin
Arrival time (T_{1 0}) For 5 to 60 minutes
It has a disk type defined in JIS-K6911
Shows more than 60mm fluidity at 100 ℃ in flow test
Heat-curable resin, and centrifuging the resin.
A tube-shaped thermosetting resin molded body was formed and was carbonized.
If a method that manages
Knowing that a lath carbon tube can be obtained
I made my wish.

In the prior invention, a centrifugal molding method is used for the production of a thermosetting resin tube which is a precursor of a glassy carbon tube as described above, and the thermosetting characteristics and the thermal flow characteristics of the thermosetting resin used are used. By efficiently escaping the gas generated during the curing reaction, it is possible to efficiently produce a centrifugally molded body (precursor tube) free from pore defects and cracks, and to carbonize the precursor tube. By processing, it is possible to produce a glassy carbon tube with the target performance, compared to the prior art described above,
It can be said that this method is extremely excellent in both production efficiency and product characteristics.

However, as the research for further improvement was continued,
It has been found that the prior invention has room for improvement in the following points.

That is, the centrifugal molding method employed in the invention of the prior application itself is a method in which the raw material resin in a molten state is caused to flow toward the inner surface side of the mold by the centrifugal force to be cured, so that the tube-shaped material can be easily molded. Thus, the molded article has a high dimensional accuracy, and has an advantage that the gas escape is good because the inner surface is open even during molding.

However, in centrifugal molding, a heat source for curing the resin must be provided outside the rotary mold due to restrictions on the apparatus, and the heating efficiency is poor. Moreover, since heat transfer to the resin necessarily proceeds gradually from the mold surface to the resin layer through the inner peripheral wall in the thickness direction of the resin layer, the progress of the curing reaction may become uneven in the tube thickness direction. . In addition, it is not impossible to provide a heating source in the mold, but not only is the configuration of the centrifugal molding apparatus complicated, but also it is difficult to control the temperature, and it is not easy to obtain a uniform heating state over the whole. . Therefore, in order to ensure a uniform curing state over the whole, the curing reaction has to be performed at a relatively low temperature for a long time, and as a result, the curing takes a considerable time and the productivity is reduced. . If the curing reaction is performed at a high temperature to shorten the curing time, defects such as bubbles and cracks are likely to occur due to the temperature distribution and local heating generated in the precursor centrifugal molded body, and these defects will be carbonized later. Since it is not cured even in the treatment step, it becomes a defect of the glassy carbon tube as the final product substantially as it is.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a thermosetting resin molding to be a precursor of a glassy carbon tube by centrifugally molding a thermosetting resin material. During molding, the thermosetting resin during centrifugal molding is efficiently cured in a short time, and a thermosetting resin molded article (glassy carbon tube precursor) free from defects such as bubbles and cracks is efficiently produced. An object of the present invention is to provide a method capable of manufacturing, and thus, a high-quality glassy carbon tube with high productivity.

[0020]

Means for Solving the Problems The manufacturing method of the present invention which solves the above-mentioned problems is to use a molding die having an increased inner peripheral surface area and centrifugally mold a raw material containing a thermosetting resin to form a thermosetting resin. The gist is that a glassy carbon tube precursor made of a resin is produced, or is further carbonized to obtain a glassy carbon tube.

The molding die used in carrying out this manufacturing method may be one having an inner peripheral surface whose surface area is increased by a surface roughening treatment, and more preferably, the surface roughness of the inner peripheral surface may be reduced by a center line average roughness. The height Ra is 1 to 10 μm, and the maximum height Rmax is 10 to 10 μm.
The surface area is increased by setting the surface roughness to 50 μm. By using a mold having such a surface roughness, a thermosetting resin tube having no internal defects and serving as a precursor of a glassy carbon tube can be efficiently produced. It is preferable because it can be used.

In the present invention, it is used as a molding raw material.
As the thermosetting resin to be obtained
As described above, the time to reach a degree of cure of 10% at 115 ° C.
(T_{1 0}) Has a curing property of 5 to 60 minutes, and JI
1 in the disk type flow test specified in S-K6911
Shows fluidity of 60mm or more at 00 ° C, solid at room temperature
(Powder) thermosetting resin or gel time 5-6
A liquid curable resin of 0 minutes is preferably used.
99% by mass or more of thermosetting resin
By using raw materials that are not contained in
Can significantly enhance the properties of glassy carbon tubing
it can. And by using such molding materials,
The glassy carbon tube obtained is heat-resistant and gas-free.
Uniform and excellent in all aspects such as permeability, corrosion resistance and durability
It has excellent performance, especially for semiconductor manufacturing CVD equipment.
Shows excellent performance as an inner tube.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have established a concrete method for promoting the above-mentioned problems, in particular, a curing reaction when centrifugally molding a thermosetting resin in a shorter time and uniformly over the whole. As a result, the productivity and homogeneity of the thermosetting resin tube-shaped centrifugal molded product, which is the precursor of the glassy carbon tube, can be increased, and the high-quality glassy carbon tube can be manufactured with high productivity. In order to do this, I have been conducting research from various angles. As a result, as described above, if the surface area of the inner peripheral surface of the centrifugal molding die is increased and the efficiency of heat transfer from the inner surface of the molding die to the resin material layer is increased, the thermosetting adhered to the inner surface of the molding die by centrifugal force It has been found that the present invention is capable of uniformly heating the conductive resin in a shorter time, thereby significantly reducing the curing time while suppressing the temperature gradient and local heating of the resin as much as possible.

In the present invention, the means for enlarging the surface area of the inner surface of the centrifugal molding die is not particularly limited. In short, any means capable of providing an effect of enlarging the effective area of heat transfer from the outer surface to the resin layer can be used. Means may be adopted, but specific means include a method of roughening the inner surface by sand blasting or shot blasting, a method of forming countless irregularities on the inner surface by laser beam irradiation, etc., In addition, a method of forming uneven strips of any shape in any direction such as a circumferential direction, a longitudinal direction, an oblique direction, a spiral direction, or a cross direction obtained by combining these in any direction can be adopted. Although the size and shape of these irregularities and irregularities are not particularly limited, a simpler and more effective method for effectively exhibiting the effect of expanding the heat transfer effective area is a method of increasing the inner surface roughness by sandblasting or shot blasting. It is.

Although the degree of the inner surface roughness is not particularly limited, it is necessary to provide an inner surface roughness of a certain degree or more in order to effectively exert the effect of improving the heat transfer efficiency by increasing the surface area. In addition, the surface of the resin molded article serving as a precursor is excessively roughened, and deteriorates the appearance as a commercial product (a precursor as an intermediate product or a glassy carbon tube obtained by carbonizing the precursor). Therefore, in order to ensure sufficient heat transfer efficiency without causing a deterioration in appearance as a product (or an intermediate product), the inner surface roughness is determined by the center line average roughness Ra.
1 to 10 μm, more preferably 3 to 7 μm, and a maximum roughness Rmax of 10 to 50 μm, more preferably 20 to 35 μm.
m is desirable.

The irregularities or irregularities have no undercuts in order to facilitate the removal of the thermosetting resin molded article after centrifugal molding, and have a mountain-like, valley-like or wavy irregularity with a relatively gentle inclination angle. Alternatively, it is desirable that the ridges are uneven.

FIG. 1 is a schematic vertical sectional explanatory view illustrating a centrifugal molding die used in the present invention, and shows a structure in which a cylindrical molding die body 1, a back plate 2 and a holding plate 3 are integrally assembled. The mold body 1 is usually provided with a split mold structure (divided into two or three or more pieces) in order to facilitate demolding after molding the precursor, and these are integrally assembled by appropriate means. After the molding, the preform is disassembled and the precursor molded body can be removed from the mold.

Then, the mold is fixed to the back plate 2, and the back plate 2 side is directly or indirectly connected to a rotation driving device (not shown) via a belt or a gear, and the pressing plate 3 side is a ball bearing. The thermosetting resin R is injected into the inside of the molding die body 1 while the molding die body 1 is rotated at a high speed by operating the rotation drive device, and the resin is centrifugally supported. The curing reaction is advanced by bringing R into fluid contact with the inner peripheral surface of the mold body 1 and heating the outer surface side with any heating means.

When performing a heat curing reaction by a centrifugal molding method,
The resin R softened or melted by the heating is pressed against the inner peripheral wall of the mold by centrifugal force, and may be used as a gas component (moisture generated by a condensation / polymerization reaction) generated along with the curing reaction, or as needed. Since the volatile vapor of the solvent or the like receives a force (buoyancy) in a direction in which it is pushed to the inner peripheral side of the tube, the forced exhaust means for these gases and vapor is not necessarily required. However, for example, if the inside of the molding die body 1 is suctioned and decompressed from the vicinity of the center of the holding plate 3 and the generated gas and the solvent vapor are forcibly exhausted, the curing reaction can be further promoted, and
This is preferable because pore defects due to generated gas and volatile vapor can be more reliably eliminated.

In the present invention, the surface area is increased by forming innumerable irregularities on the inner peripheral surface of the mold body 1 for centrifugal molding as described above. As a result, heat from the outer surface side of the molding die body 1 is efficiently and uniformly transmitted to the thermosetting resin layer R to be centrifugally molded, and the curing of the thermosetting resin layer R proceeds rapidly. That is, in the present invention, the irregularities formed on the inner surface side of the mold main body are provided in order to efficiently transfer heat from the outer surface side of the mold to the thermosetting resin layer R to promptly and uniformly progress the curing reaction. Because there are no restrictions on the shape, structure, size, etc.,
As described above, various modes of unevenness are included.

When the production method of the present invention is employed, the irregularities formed on the inner peripheral surface of the mold 1 are transferred to the outer peripheral surfaces of the precursor tube and the glassy carbon tube as the final product, and the irregularities are formed. However, the most influential on the quality of the inner tube used in the CVD apparatus for semiconductor manufacturing is shown in FIG. 2 which is a conceptual diagram of the CVD apparatus (in the figure, 4 is an inner tube, 5 is an outer tube, 6 is a Si wafer, 7 is a boat for supporting a wafer, and 8 is a source gas, respectively).
Since the properties of the outer peripheral surface of the inner tube have almost no effect, irregularities on the outer peripheral surface do not become defects in quality.

As the raw material resin used in the present invention, various thermosetting resins such as a phenolic resin, a furan resin and an epoxy resin can be used. Particularly preferred in the present invention are shown below. It is a solid (powder) thermosetting resin having similar curing properties and fluidity during heating, or a liquid thermosetting resin having a gelation time of 5 to 60 minutes.

That is, the thermosetting resin particularly preferably used as a tube material in the present invention has a resin curing degree of 1
In addition to having a curing property of not less than 5 minutes and not more than 60 minutes at 115 ° C. to reach 0% (T ₁₀ ), JIS-K6
It is a solid (powder) thermosetting resin exhibiting a fluidity at the time of heating of not less than 60 mm at 100 ° C. in a disc flow test specified in 911, or a liquid thermosetting resin having a gelation time of 5 to 60 minutes. .

That is, when the thermosetting resin is subjected to centrifugal molding, it is necessary to flow or plastically deform the molten resin into a cylindrical shape along the inner peripheral surface of the mold before completing the curing reaction of the raw resin. since there are, the curing characteristics of the powder-like thermosetting resin resin, preferably those T ₁₀ at 115 ° C. is not less than 5 minutes. Gas said T ₁₀ is the case where less than 5 minutes, contained or curing of the resin is completed before the material is deformed into a cylindrical shape along the inner peripheral surface of the mold by centrifugal force, or the raw material resin The curing of the resin is completed before the components and gas components generated during molding (or solvent vapor which may be mixed) are dissipated, which may cause pore defects and cracks.

[0035] More preferred time T ₁₀ is not less than 10 minutes, if longer time until completion of curing, it is possible to perform the centrifugal molding with a smaller centrifugal force (less speed). However, resin curing time is too long, generally tends to generate a large amount of gas during the curing reaction in the rotary, so liable to occur pore defects, the T ₁₀ is less than 60 minutes, more preferably within 40 minutes It is desirable to use one.

It should be noted the T ₁₀ in the present invention uses a Curelastometer, sandwiched sample between the set upper and lower molds to 115 ° C., the rotational vibration of the minute angle in addition to the one mold,
The generated shear stress (torque) is continuously measured. The time required for the resin to completely cure and reach a constant torque is represented by T
And _100, a to reach 10% torque time was T _10.

In centrifugal molding of a powdery thermosetting resin,
Since the centrifugal molding is performed at a temperature higher than the temperature at which the resin undergoes a curing reaction, it is necessary that the thermosetting resin used as a raw material has an appropriate fluidity at the molding temperature when heated. Therefore, in the present invention, JIS-K6911
It is desirable to use one having a fluidity value of 60 mm or more when the disk-type flow test specified in (1) is performed at 100 ° C. In this test, the temperature was set to 100 ° C. for the following reason. That is, the curing reaction of the thermosetting resin usually starts around 100 ° C., and the fluidity of the resin gradually decreases as the curing reaction proceeds. Therefore, in order to shape the resin into a cylindrical shape by centrifugal force, it is essential that the resin undergoes an appropriate flow deformation at this temperature. In order to evaluate such a flowability under heat, the test temperature is set to 100 ° C. I have.

If the value of the fluidity of the molding raw material confirmed in this test is less than 60 mm, it becomes difficult to form a desired cylindrical shape even when a large centrifugal force is applied under heating. If the resin shows a value of 60 mm or more, it can be shaped into a cylindrical shape by centrifugal molding, but at a lower rotation speed, and in order to smoothly carry out centrifugal molding in a short time, the value is 100 mm or more. It is desirable to use those.

Although the upper limit of the above-mentioned hot fluidity of the raw material resin does not particularly exist, a resin having excessively high fluidity during hot generally contains a large amount of low molecular weight oligomer components, so that a large amount of gas is generated during the curing reaction. Since the foaming of the raw material resin becomes remarkable and the pore defects are likely to occur, or the curing takes a long time, which may cause a decrease in productivity. It is desirable to use a resin of 150 mm or less.

When a liquid thermosetting resin is used, if the gelation time is less than 5 minutes, the curing proceeds before the generated gas is dissipated, resulting in poor outgassing and resulting in pore defects and cracks. And the gelation time is 60
If the amount exceeds the limit, the final cured product may be insufficiently cured. In addition, the said gel time is JIS K69.
It refers to the gel time determined at 115 ° C. in accordance with the “room temperature gel time” measurement method specified in No. 01, and the more preferable gel time of the liquid thermosetting resin is 10 to 40 minutes.

As described above, by using a powdery thermosetting resin having proper curing characteristics and fluidity during heating or a thermosetting resin having an appropriate gelation time as a raw material,
Conventionally, even when using a resin containing no filler, which was almost impossible to centrifugally mold, it is possible to reliably produce a tube-shaped precursor resin molded article without cracks or pore defects, and furthermore, By subjecting this to a carbonization treatment according to a conventional method, a glassy carbon tube having no defect can be manufactured with high productivity.

As the raw material resin used in the present invention, any resin can be used as long as it exhibits appropriate fluidity and curing properties at the time of heating as described above. Although a thermosetting resin may be used, a thermosetting resin in powder form is particularly preferably used. The reason is that in the case of a liquid resin or a solution resin dissolved in a solvent,
Even if it has favorable thermal fluidity and curing characteristics, it is easy to cause foaming due to gas and solvent vapor generated in the centrifugal molding process, and a thermosetting resin tube as a precursor or carbonized This is because vacancy defects easily occur in the glassy carbon tube obtained by the treatment.

In particular, when the present invention is used for manufacturing an inner tube of a CVD apparatus for manufacturing semiconductors, 95% or more of a thermosetting resin having the above-mentioned preferable fluidity and hardening properties at the time of molding is used as a molding material. It is more preferable to use a raw material occupying 99% or more, and it is preferable because impurity contamination at the time of manufacturing a semiconductor using the inner tube for a CVD apparatus for manufacturing a semiconductor can be reduced as much as possible.

As described above, phenol resin and furan resin are particularly preferably used as the thermosetting resin used as a molding material. Among them, phenol resin is a material after carbonization. The yield is large and the dimensional change is small compared to other thermosetting resins. Therefore, it is preferable in obtaining a glassy carbon pipe having a desired shape and dimensions. In addition, the fluidity and curing characteristics of the resin raw material when heated can be controlled by the type of the thermosetting resin contained, the amount of the curing catalyst used, the heating temperature, and the like, and can also be adjusted by the type and amount of the filler and the solvent. It is possible.

In producing a thermosetting resin molded article by centrifugal molding, a raw material containing a thermosetting resin is charged into a substantially cylindrical mold rotatable in a circumferential direction, and the substantially cylindrical mold is removed. The resin may be heated to the curing temperature of the resin while rotating to produce a substantially cylindrical thermosetting resin molded body.

In manufacturing the thermosetting resin tube, as shown in FIG. 1, a molding die 1 having an appropriate surface irregularity formed on the inner peripheral surface to increase the surface area is used. The raw material resin is charged into the mold 1 and the mold 1 is heated while rotating at a high speed to perform centrifugal molding. As described above, it is recommended to use a split mold as the molding die 1 used here. There is no particular limitation on the material of the mold 1, such as metal materials such as SUS, ceramics,
Alternatively, a resin or the like can be used, but a metal is most common in consideration of strength, workability (including inner surface roughening) and the like.

According to the present invention, since the outer diameter and the length of the precursor resin tube and the glassy carbon tube are determined by the inner diameter and the length of the mold 1, the inner diameter and the length of the mold 1 are changed. Thus, a precursor tube having an arbitrary outer diameter and length can be obtained. Further, the inner diameter of the tube can be arbitrarily adjusted by changing the amount of the resin loaded in the mold 1.

The raw material resin R is loaded into the molding die 1 as shown in FIG. 1, and the resin may be loaded while the molding die 1 is stationary or while rotating. May go. The rotational speed of the mold 1 should be appropriately selected and determined according to the diameter of the mold, the curing properties of the resin, and the fluidity during heating. However, in order to more reliably obtain a precursor molded body having no void defects, , About twice the gravity, preferably 1 centrifugal force
It is desirable to set the gravitational force of about 0 G or more to act on the resin layer R, and the preferable rotation speed varies depending on the inner diameter of the mold 1, but it is usually 500 to 5,000 rpm, more generally 1,000 rpm. 3,000 rpm.

When the raw material resin is loaded into the molding die 1 and heated from the outer surface side of the molding die 1 while rotating the die, and the resin is heated to a temperature at which the curing reaction proceeds, the raw resin is melted by heating, It is pressed against the inner peripheral surface of the mold 1 by centrifugal force generated by the rotation of the mold 1, and is formed into a tube having a substantially constant inner diameter and a uniform thickness. At this time, the inner peripheral surface of the molding die 1 has been subjected to the surface area expansion processing as described above,
The heat from the outer peripheral surface is uniformly and promptly transmitted to the resin layer R through the inner peripheral surface whose surface area is enlarged by roughening or the like,
The curing reaction proceeds quickly.

During this time, volatile components that may be contained in the raw material resin and gas components generated during the molding process are dissipated from the inner surface of the resin layer R. As described above, it is preferable to forcibly evacuate the resin layer R from the inner surface side in order to promote the dissipation of the gas component and to more reliably suppress the generation of pore defects.

Since various gases such as water vapor are generated during the curing reaction of the thermosetting resin, it is important to release the gas during molding. For example, a large-diameter pipe such as an inner tube for a CVD apparatus is compressed. In the case of molding by such a general method, degassing is practically impossible, and
When the molded body is taken out of the mold at a stage where the curing reaction is insufficient to suppress generation of gas, the molded body is deformed, so that the shape cannot be maintained.

On the other hand, in the method of the present invention, a compressive force acts on the resin layer due to the centrifugal force generated by the rotation of the mold. Since the surface of the tube that is not in contact with the mold (the inner surface side) is open to the atmosphere, the generated gas easily dissipates outside the molded body. Further, the resin is heated while receiving a compressive force due to centrifugal force, and the curing reaction can be advanced to a completely cured state while extruding the gas component toward the inner surface side of the resin layer R. The temperature at the time of centrifugal molding differs depending on the type of resin used, the curing catalyst, and the like, but is usually 80 ° C or higher, preferably 100 ° C or higher.

After the thermosetting resin tube serving as the precursor is thus formed, it is converted into a glassy carbon tube by carbonization. The carbonization treatment does not require exceptional special conditions, and is performed by heating the precursor tube in a non-oxidizing atmosphere at a temperature of usually about 800 ° C. or more, preferably about 1000 ° C. or more, according to a conventional method. If necessary, before the carbonization treatment, a post-curing treatment (curing) in which the precursor tube is heated to about 100 to 300 ° C. in the air or in a non-oxidizing atmosphere can be performed.

Thus, according to the present invention, the diameter is, for example, 1
Even in the case of a precursor resin tube having a large diameter of 5 mm or more (and 60 mm or more), heat curing of the resin layer is promoted efficiently and as uniformly as possible by the effect of improving the heat transfer efficiency from the mold to the resin layer. It is possible to efficiently produce a precursor resin tube having no internal defects under excellent productivity, and by performing carbonization treatment on the precursor resin tube according to a conventional method, there is no dimensional accuracy without internal defects. It is possible to efficiently produce a glassy carbon pipe excellent in quality. In particular, according to the present invention, a large-diameter tube can be obtained without any obstacle even from a raw material substantially consisting of only a thermosetting resin, and an inner tube for a CVD apparatus for semiconductor production which does not cause an impurity obstacle. Can be used very effectively.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are not intended to limit the present invention, and the present invention will not be limited to the following Examples and Examples. Modifications can be made and implemented, all of which are included in the technical scope of the present invention.

Example 1 An inner diameter 325 made of SUS304 material was used as a centrifugal molding die.
A mold having a diameter of 2 mm and a length of 1000 mm and having a two-part cylindrical shape and having the entire inner peripheral surface roughened by shot blasting was used. As shot blast material, the particle size is 0.4m
m using a near white metal (Steel Shot manufactured by Shinto Breiter Co., Ltd.), using a blast speed of 80 m / s and a blast material amount of about 50 kg / m ² , and using the surface roughness as the center line average roughness Ra. The thickness was adjusted to about 5 μm and the maximum roughness Rmax to about 30 μm.

In this mold, the tube thickness is about 3 mm.
The following amount of thermosetting resin (about 3 kg) was charged so as to be calculated as follows, and the inner peripheral surface of the mold was heated to 120 ° C. at a rate of 5 ° C./min while rotating the mold at 1000 rpm. The mold was kept at the same temperature for 2 hours, and the mold was heated using a heater arranged so as to surround the rotating mold. The heating temperature was measured with a thermocouple embedded in the inner peripheral surface of the mold. Thereafter, the molded body was allowed to cool to room temperature and then released from the mold.
Was obtained. During demolding, the molded body can be easily demolded by uniform moderate shrinkage, and no deformation, cracking, or internal foaming is observed in the obtained tubular molded body. No residual was observed.

[Raw material resin] Thermosetting resin: 100 parts by mass of a liquid phenol resin (trade name “REGITOP PL-4804” manufactured by Gunei Chemical Co., Ltd.) and 5 parts by mass of tetramethylenehexamine (HTM) as a curing catalyst are mixed. And stirred at 65 ° C. for 1 hour. Gel time: 30 minutes

Comparative Example 1 A phenol resin tube was subjected to centrifugal molding in the same manner as in Example 1 except that a mold whose entire inner peripheral surface was mirror-finished was used.

In the obtained tube, local adhesion to the mold, which is considered to be caused by uneven heating, occurred. When the mold was released, the tube became a starting point, and cracks occurred. In addition, residual bubbles were observed in some places on the inner peripheral surface of the obtained tube.

Example 2 The same centrifugal mold as that used in Example 1 was used, and the amount (about 3 kg) calculated so that the tube thickness was about 3 mm in this mold. Is filled with the following solid phenolic resin, and the inner peripheral surface of the mold is heated to 150 ° C. at a rate of 5 ° C./min while rotating the mold at 1000 rpm, and the mold is heated for 2 hours. Is
The heating was performed using a heater arranged so as to surround the rotating mold, and the heating temperature was measured by a thermocouple embedded in the inner peripheral surface of the mold. Thereafter, the molded body was allowed to cool to room temperature and then released from the mold.
m was obtained.

[Raw material resin] Phenol and formalin were mixed at a molar ratio of 1: 0.8, and oxalic acid was added as a catalyst in an amount of 2% by mass based on phenol.
Stir for ~ 4 hours. Thereafter, water and low molecular weight components were distilled off under reduced pressure to obtain a solid phenol resin, and each was subjected to the centrifugal molding.

[0063] Table 1 shows the T ₁₀ and hot fluidity and molding results of the solid phenolic resin used in the above experiments.

[0064]

[Table 1]

[0065] As is evident from Table 1, codes with proper T ₁₀ and solid phenolic resin having a hot fluidity b~
In (d), a good phenol resin tube free from pore defects and the like was obtained. On the other hand, T ₁₀
In the case of a solid phenol resin having an extremely long flowability and a high fluidity during heating, a large amount of gas is generated at the time of centrifugal molding, and traces of bubbles are not completely eliminated. Also, in T ₁₀ is extremely short hot flowable low solids phenolic resin as code e, resin flowability progressed cured before being centrifugal molding is lost cylindrical, uniform shaping of thick You lose your body.

Example 3 Example 2 was repeated except that the following liquid phenol resin was used.
The phenol resin tube was subjected to centrifugal molding in exactly the same manner as in the above.

[Raw material resin] A commercially available liquid resol type phenol resin (viscosity: 0.5 Pa · s, non-volatile content: 60)
Mass%) and hexamethylenetetramine in a mass ratio of 10%.
After mixing at a ratio of 0: 2 and stirring at 70 ° C. for 0.5 to 4 hours, water and low molecular weight components were distilled off under reduced pressure to produce a liquid phenol resin, which was subjected to the centrifugal molding.

Table 2 shows the gel time and molding results of each solid phenolic resin used in this experiment.

[0069]

[Table 2]

As is clear from Table 2, the reference numerals B to D using the liquid phenol resin having an appropriate gelation time provide good phenol resin tubes free from pore defects and the like. On the other hand, in the case of a liquid phenol resin having an excessively long gelation time as indicated by the symbol A, it is difficult to remove the mold due to insufficient curing, and a large amount of gas is generated during centrifugal molding, and the trace of bubbles is not completely eliminated. Therefore, many defects are seen in the molded body. Further, in the case of a liquid phenol resin having an extremely short gelation time such as E, the gelation proceeds and the viscosity increases before the resin is centrifugally molded into a cylindrical shape, and the escape of the internal gas becomes insufficient. In addition to the formation of pore defects, gelation proceeds before centrifugal molding, and a molded article having a uniform thickness cannot be obtained.

Example 4 An inner diameter 325 made of SUS304 material was used as a centrifugal molding die.
A mold having a two-part cylindrical shape having a length of 2,000 mm and a length of 2,000 mm and having the entire inner peripheral surface subjected to four types of surface roughening treatments shown in Table 2 by shot blasting was used. As the shot blast material, a near white metal having a particle size of 0.2 to 0.8 mm (steel shot manufactured by Shinto Breiter Co., Ltd.) is used, the blast speed is 65 to 110 m / s, and the blast material amount is about 50 kg / m ^2. Was adopted to adjust the surface roughness. The surface roughness of the inner surface of the mold was measured using a stylus roughness meter manufactured by Rank Taylor Co., Ltd.
It was measured in accordance with IS B0651.

Into this mold, 6 kg of the same thermosetting resin as used in Example 1 was charged, and the inner peripheral surface of the mold was heated to 100 ° C. while rotating the mold to perform centrifugal molding. Was. The heating of the mold was performed using a heater arranged so as to surround the rotating mold, and the heating temperature was measured in advance by a thermocouple embedded in the inner peripheral surface of the mold.

While maintaining the same temperature, the mold was continuously rotated at a speed of 600 rpm, and the time required for the mass reduction rate of the resin layer to reach 20% by mass was measured. This is because, when the above-mentioned phenol resin is used, the curing is almost completed when the mass reduction rate reaches 20% by mass, and the subsequent demolding and carbonization can be performed without any trouble. The mass reduction rate was determined by quantifying the water generated from the raw resin, that is, the sum of the excess water evaporated from the raw resin and the water generated by the curing reaction. When the mass reduction rate reaches 20% by mass, the centrifugal molding is terminated, and the molded body is allowed to cool to room temperature, and then the molded body is removed from the mold. I got Table 3 shows the curing time for producing each resin tube.

Each phenol resin tube obtained above was
After curing by heating in air at 300 ° C for 200 hours, it is further heated up to 2000 ° C in an inert gas (argon).
Over 0 hours, heat and heat to carbonize, outer diameter 260m
A tube made of glassy carbon having a length of 1600 mm, a length of 1600 mm and a thickness of about 2.1 mm was obtained. Both ends of the tube were cut to form a 1000 mm long inner tube for CVD, and the performance as an inner tube for CVD was evaluated by the following method.

[Performance evaluation method as inner tube]
Each of the inner tubes obtained above was replaced with a vertical semiconductor manufacturing C
SiH ₄ at 650 ° C CVD temperature
By supplying a mixed gas of H ₂ and H ₂ , a polysilicon film was formed on the Si wafer. The performance of the inner tube was evaluated based on the amount of particles (foreign matter) attached to the surface of the polysilicon film. The amount of particles generated is determined by measuring the number of particles of 0.2 μm or more adhering to the surface of the silicon wafer to “6” manufactured by Tencor.
220 type ".

The results are collectively shown in Table 3. For the performance as the inner tube, the results of the same evaluation test performed on the conventional quartz and SiC inner tubes are also shown.

[0077]

[Table 3]

As is clear from Table 3, if the method of the present invention in which the inner surface of the mold is roughened is employed, the curing time of the thermosetting resin during centrifugal molding can be greatly reduced. . Also, by roughening the inner surface of the mold,
The peripheral surface of the obtained thermosetting resin tube, and thus the glassy carbon tube, is also roughened. Even when the performance as an inner tube for a CVD apparatus is compared with that of a conventional quartz or SiC, It can be seen that the tube obtained by the method has a small particle generation amount and has excellent performance.

[0079]

The present invention is configured as described above.
For example, a high-performance glassy carbon tube that can be effectively used as an inner tube or the like of a CVD apparatus for semiconductor production and a thermosetting resin tube as a precursor thereof can be stably and reliably produced with high productivity.

[Brief description of the drawings]

FIG. 1 is a schematic sectional explanatory view illustrating a centrifugal molding die used in the present invention.

FIG. 2 is a schematic cross-sectional explanatory view illustrating a CVD apparatus for manufacturing a semiconductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold main body 2 Back plate 3 Holding plate 4 Inner tube 5 Outer tube 6 Si wafer 7 Wafer support boat 8 Raw material gas R Thermosetting resin (layer)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/205 C23C 16/44 B 5F045 // C23C 16/44 B29K 101: 10 B29K 101: 10 B29L 23: 00 B29L 23:00 C08L 61:06 C08L 61:06 C04B 35/52 A F term (reference) 3H111 BA15 BA37 CB02 CB23 DA08 DB10 DB11 EA07 EA12 4F073 AA12 AA13 AA17 BA21 BB03 GA01 GA03 4F205 AA37 AG01 GS01 GN28 4G032 AA14 BA02 GA06 GA11 4K030 KA46 5F045 BB08 BB14 DP19 EC02 EC05

Claims (8)

[Claims] 1. A method for producing a glassy carbon tube precursor, wherein a raw material containing a thermosetting resin is centrifugally molded by using a mold having an increased inner peripheral surface area. 2. A thermosetting resin tube is produced by centrifugally molding a raw material containing a thermosetting resin by using a mold having an increased inner peripheral surface area, and a carbonizing treatment is performed on the tube. To make vitreous carbon tubes. 3. The method according to claim 1, wherein the inner peripheral surface of the mold has a surface area increased by a roughening treatment. 4. The surface roughness of the inner peripheral surface of the mold is 1 to 10 μm in center line average roughness Ra and 10 to 50 in maximum roughness Rmax.
The method according to claim 3, wherein the particle size is μm. 5. The method according to claim 1, wherein the glassy carbon tube is an inner tube of a CVD apparatus for semiconductor production. 6. A thermosetting resin having a hardening property in which a reaching time (T ₁₀ ) to a hardening degree of 10% at 115 ° C. is 5 to 60 minutes, and a disk flow test specified in JIS-K6911. The method according to any one of claims 1 to 5, wherein a thermosetting resin which is solid at room temperature and has a fluidity of not less than 60 mm at 100 ° C is used. 7. The thermosetting resin has a gelation time of 5 to 5.
The method according to any one of claims 1 to 5, wherein a thermosetting resin liquid at room temperature for 60 minutes is used. 8. The method according to claim 1, wherein 99% by mass or more of the raw material is a thermosetting resin.