JP2003226576A - Method of manufacturing vitreous carbon cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method to obtain a vitreous carbon cylinder high in circularity. <P>SOLUTION: The vitreous carbon cylinder is manufactured by heat-treating a thermosetting resin cylinder at 800-1,300°C under an inert gas atmosphere to obtain a vitreous carbon cylinder 2 before a high temperature heat treatment, applying circularity correcting die 4 on the outside of the vitreous carbon cylinder 2 before the high temperature treatment, heat-treating the vitreous carbon cylinder 2 before the high temperature treatment at a high temperature of ≥1,500°C with the circularity correcting die 4 under an inert atmosphere. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A glassy carbon cylindrical body is suitably used as a core tube of a vapor phase reaction furnace, an inner tube of a CVD apparatus for semiconductor production, and the like. The present invention relates to a manufacturing method for obtaining a glassy carbon cylinder having a high roundness.

[0002]

2. Description of the Related Art Glassy carbon is a carbon material obtained by heat-treating a thermosetting resin, and has a glassy very homogeneous and dense structure. This material has the characteristics of general carbon materials such as thermal conductivity, chemical stability, heat resistance, and high purity, as well as the excellent characteristics that constituent particles do not fall off. It is used for applications such as manufacturing equipment members.

The glassy carbon cylinder made of glassy carbon can be obtained by preparing a thermosetting resin cylinder and heat-treating it in an inert atmosphere. That is,
In an inert atmosphere, a temperature of generally 800 ° C or higher,
Preferably 1000 to 1200 ° C., more preferably 1
By heat-treating at 300 to 2500 ° C., a glassy carbon cylinder is obtained.

However, the glassy carbon has a large degree of roundness (good roundness) because it shrinks greatly in the process of carbonizing and firing the thermosetting resin cylindrical body and has a volume shrinkage of about 20%. It was difficult to obtain a glassy carbon cylinder.

Therefore, for the purpose of ensuring the roundness, for example, Japanese Patent Laid-Open Nos. 11-189470 and 11-18.
No. 9471 discloses that a graphite core is placed inside a thermosetting resin cylinder before carbonization and firing, and a graphite core is placed inside a glassy carbon cylinder before high temperature heat treatment. A method of arranging them is proposed. Specifically, in consideration of shrinkage of the thermosetting resin cylindrical body during carbonization and firing, a core having the same outer diameter as the inner diameter of the target glassy carbon cylindrical body is used.

[0006]

However, as a result of studies by the present inventor, in the above-mentioned conventional method using the core, a glassy carbon cylindrical body having a high roundness (good roundness) is surely obtained. It turns out that it is not always possible. Then, the present inventor has found that the reason why the roundness is not improved is that the glassy carbon cylindrical body expands at a temperature of 1200 ° C. or higher in the high temperature heat treatment performed after the carbonization and firing.

The present invention was created based on the above findings, and an object thereof is to provide a method for manufacturing a glassy carbon cylindrical body having a high roundness.

[0008]

In order to achieve the above object, the invention of claim 1 is characterized in that the thermosetting resin cylindrical body is heat-treated at a temperature of 800 to 1300 ° C. in an inert atmosphere before the high temperature heat treatment. To obtain a glassy carbon cylinder, and then place the roundness correction mold on the outside of the glassy carbon cylinder before the high temperature heat treatment, and thereafter, before the high temperature heat treatment in an inert atmosphere. A method for manufacturing a glassy carbon cylinder, which comprises subjecting a glassy carbon cylinder to a high temperature heat treatment at a temperature of 1500 ° C. or higher together with the roundness correcting mold.

According to a second aspect of the present invention, in the method for manufacturing a glassy carbon cylinder according to the first aspect, the roundness correcting die is made of graphite.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below.
In the method for manufacturing a glass-like carbon cylinder according to the present invention, first, a thermosetting resin cylinder is heated in an inert atmosphere at 800 to
By heat-treating (carbonizing and firing) at a temperature of 1300 ° C., the thermosetting resin cylindrical body undergoes volumetric shrinkage to be glassy carbonized to become a glassy carbon cylindrical body before high-temperature heat treatment.
In this case, in the heat treatment (carbonization firing), from the viewpoint of ensuring roundness, it is preferable to arrange the cylindrical core inside the thermosetting resin cylindrical body and perform the heat treatment. Next, a roundness correction mold is arranged outside the glassy carbon cylinder before the high temperature heat treatment so as to surround the cylinder. Thereafter, the glass-like carbon cylindrical body before the high temperature heat treatment in an inert atmosphere together with the roundness correcting mold at a temperature of 1500 ° C. or higher,
For example, high temperature heat treatment is performed at 1500 ° C. By being subjected to the heat treatment at this high temperature, the circularity straightening mold simply thermally expands by passing through the temperature range of 1200 to 1500 ° C., while the glassy carbon cylindrical body thermally expands. In addition,
Expands due to the structural change of carbon. As a result, the glassy carbon cylindrical body after the high temperature heat treatment is fixed to the shape of the circular inner peripheral wall surface of the roundness correcting type (following the shape of the circular inner peripheral wall surface) and has a high circularity. Become.

FIG. 1 is a graph showing an example of the relationship between the temperature and the change in length when the glassy carbon molded product before the high temperature heat treatment is heated. The heating rate is 200 ° C./h. The glass-like carbon molded body (test piece), which is a rectangular parallelepiped having a thickness of 2 mm, a width of 2 mm, and a length of 20 mm, was heat-treated (carbonized and fired) at a temperature of 900 ° C.

As can be seen from FIG. 1, glassy carbon production
The feature expands to about 950 ° C. and then expands to 950-120
Shrinks between 0 ° C and 0 to above 1200 ° C
Re-increasing at an increasing slope greater than that at 900 ° C
And the behavior of expanding. 0 to 900 ℃
The linear expansion coefficient of the glassy carbon molded product is 3 × 10. ^-6
(K^-1). On the other hand, between 1200 and 1500 ° C
The glassy carbon molding is approximately 10 x 10^-6(K^-1) Line
The coefficient of linear expansion is indicated by the coefficient of linear expansion and the coefficient of linear expansion.
Number 3 x 10^-6(K^-1) Is the temperature range 1200
This is due to the structural change peculiar to -1500 ° C. Tsuma
Molded glassy carbon (in this example, carbonized at 900 ° C
(Baked) has a temperature range of 1200 to 1500 ° C.
When passing for the first time, it expands. This expansion is strange
The mechanism of carbonization is not clear, but the structure of carbon
It is thought to be due to changes.

From the above, heat treatment (carbonization firing) for obtaining a glassy carbon cylindrical body to be subjected to high temperature heat treatment
The temperature should be 1200 ° C to 1500 ° C in the next high temperature heat treatment for the first time, and 1200 ° C or less is preferable from Fig. 1, considering that there is some variation depending on the raw material resin. The upper limit value was set to 1300 ° C. The lower limit of the heat treatment (carbonization and firing) temperature was set to 800 ° C. at which the thermosetting resin cylindrical body was vitrified into carbon. In this case, it is desirable that the lower limit of the material shrinkage is almost completed (in the case of the glassy carbon molded product heat-treated at 900 ° C., the material temperature is between 950 and 1200 ° C. as shown in FIG. (Shrinkage has occurred) It is preferable that the value is as close as possible to 1200 ° C. Because in high temperature heat treatment, this 950-12
When the glassy carbon cylinder has a large shrinkage when passing through the temperature range of 00 ° C., the glassy carbon cylinder is too far from the circular inner peripheral surface of the roundness correcting type surrounding the glassy carbon cylinder, This is because the correction effect due to the subsequent expansion phenomenon cannot be obtained. The reason why the temperature is set to 1500 ° C. or higher in the high temperature heat treatment is that if the temperature is lower than this temperature, the effect of correcting the roundness due to the expansion phenomenon due to the structural change cannot be sufficiently obtained. The upper limit of the temperature range of the high temperature heat treatment depends on the quality of the intended glass-like carbon cylinder, the operating temperature, etc., but is usually 2500 ° C.

The roundness correction type material used in the present invention is preferably one having heat resistance and a linear expansion coefficient as close as possible to that of a glassy carbon cylinder which is heat-treated at a high temperature, and graphite is preferable. Other examples include glassy carbon and carbon fiber molded bodies.

[0015]

EXAMPLES Next, examples will be described. First, a phenol resin cylindrical body 1 having a thickness of 2.5 mm, an outer diameter of 330 mm and a length of 1200 mm was produced. As a resin raw material,
A commercially available phenol resin (PL-4804 manufactured by Gunei Chemical Industry Co., Ltd.) was dehydrated and used, and a phenol resin cylindrical body 1 was produced by a centrifugal molding method using a centrifugal molding machine equipped with a centrifugal molding die. The centrifugal molding method is a method in which a thermosetting resin in a molten state is caused to flow to the inner surface side of a centrifugal molding die by a centrifugal force to be cured. According to centrifugal molding method, outer diameter is 300m
It is easy to mold a large-diameter and long thermosetting resin cylindrical body having a diameter of more than 1000 mm and a length of more than 1000 mm, and a cylindrical body with good dimensional accuracy can be obtained. Further, the inner surface side is released at the time of molding. Therefore, it is possible to obtain a thermosetting resin cylindrical body with good gas release and no pore defects inside.

Next, as shown in FIG. 2, a phenol resin cylindrical body 1 having a carbon fiber felt core (hereinafter simply referred to as felt core) 3 disposed inside thereof is carbonized and fired at a temperature of 1200.degree. Then, a glassy carbon cylinder 2 was obtained. That is, core 3 with felt inside
Put the phenolic resin cylinder 1 where is placed in an electric furnace,
1200 ° C at a heating rate of 2 ° C / h in a nitrogen atmosphere
The phenol resin cylindrical body 1 is carbonized and baked by raising the temperature to 1,200 ° C. for 1 hour, and then the felted core 3 is removed to obtain a thickness of 1.9 mm, an outer diameter of 249 mm in terms of a perfect circle, and a long length. A glassy carbon cylindrical body 2 having a length of 900 mm before high temperature heat treatment was obtained. Here, as shown in FIG. 2, the felted core 3 has a graphite cylindrical body 3a having a thickness of 15 mm, an outer diameter of 240 mm and a length of about 1200 mm.
One layer of carbon fiber felt 3b having a thickness of 3 mm is wound around the outer peripheral surface of.

3A and 3B are views showing an example of a roundness correction mold used for carrying out the present invention, in which FIG. 3A is a plan view and FIG. 3B is a sectional view taken along line AA of FIG. Is. As shown in FIG. 3, the roundness correction mold 4 made of graphite has an outer shape of 300 m on each side.
It has a square shape of m and a thickness of 30 mm, and has a circular through hole 4a having a diameter of 250 mm at the center thereof.
It is possible to insert the glassy carbon cylinder 2 into the circular through hole 4a.

Then, as shown in FIG. 4, a roundness correcting die 4 is placed outside the one end portion of the glassy carbon cylinder 2 and placed in an electric furnace for high temperature heat treatment. It was That is, in a nitrogen atmosphere, the temperature is raised to 1200 ° C. at a temperature rising rate of 20 ° C./h, and further raised from 1200 ° C. to 1500 ° C. at a temperature rising rate of 2 ° C./h.
It was kept at 500 ° C. for 1 hour to obtain a large-diameter and long glass-like carbon cylindrical body that had been subjected to high-temperature heat treatment. After the high temperature heat treatment, the roundness correcting mold 4 was removed.

The deviation of the outer diameter (difference between the maximum outer diameter and the minimum outer diameter) at the end portion of the obtained glassy carbon cylindrical body on the side where the roundness correcting mold 4 was disposed is , 0.3
It was mm. In this way, a large-diameter and long glass-like carbon cylinder having a high roundness was obtained. This glassy carbon cylinder is suitable as an inner tube of a plasma CVD apparatus for semiconductor production, which requires a particularly high roundness on one end side of the cylinder.

Next, a comparative example will be described. First, similarly to the example, the thickness is 2.5 mm, the outer diameter is 330 mm,
A 1200 mm long phenolic resin cylinder was produced. Next, the felted core 3 was placed inside the phenol resin cylinder, and heat treatment was performed.

That is, the phenol resin cylinder having the felt core 3 inside is placed in an electric furnace,
1500 at a heating rate of 2 ° C./h in a nitrogen atmosphere
The temperature was raised to ℃ and held at 1500 ℃ for 1 hour to perform heat treatment. The glass-like carbon cylindrical body of the obtained comparative example has a deviation of its outer diameter (difference between the maximum outer diameter and the minimum outer diameter) of 1.2 mm, and has a lower roundness than that of the example. It was a thing.

[0022]

As described above, according to the method for producing a glassy carbon cylinder according to the present invention, it is suitable as an inner tube of a plasma CVD apparatus for semiconductor production.
A glassy carbon cylinder having a high roundness can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing an example of a relationship between a temperature and a change in length when a glassy carbon molded product before high temperature heat treatment is heated.

FIG. 2 is a cross-sectional view showing a state in which carbon fiber felt cores are arranged inside a phenol resin cylindrical body in an example.

3A and 3B are views showing an example of a roundness correction mold used for implementing the present invention, in which FIG. 3A is a plan view and FIG. 3B is a sectional view taken along line AA.

FIG. 4 is a cross-sectional view showing a state in which a roundness correcting mold is fitted and arranged on the outside of a glassy carbon cylinder before high temperature heat treatment in an example.

[Explanation of symbols]

1 ... Cylinder made of phenolic resin 2 ... Cylinder made of glassy carbon before high temperature heat treatment 3 ... Core made of carbon fiber felt 3a ... Cylindrical body made of graphite 3b ... Carbon fiber felt 4 ... Roundness correction type 4a ... Circular shape Through hole

Claims (2)

[Claims] 1. A thermosetting resin cylinder is heat-treated in an inert atmosphere at a temperature of 800 to 1300 ° C. to obtain a glassy carbon cylinder before high temperature heat treatment, and then the glassy carbon before high temperature heat treatment. A circularity correction mold is placed on the outside of the cylindrical body, and then the glassy carbon cylinder before the high temperature heat treatment is performed in an inert atmosphere together with the circularity correction mold at a temperature of 1500 ° C. or higher. A method for manufacturing a glass-like carbon cylindrical body, characterized in that the glass-like carbon cylinder is heat-treated at high temperature. 2. The method for manufacturing a glassy carbon cylindrical body according to claim 1, wherein the roundness correcting mold is made of graphite.