JP2001332504A - Cvd inner tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inner tube which is used in a semiconductor manufacturing CVD apparatus, possessed of excellent heat-resistant and corrosion-resistant properties and an inner surface giving high adhesion to a CVD film component, and capable of protecting an Si wafer against contamination to the utmost. SOLUTION: An inner tube used in a semiconductor manufacturing CVD apparatus is formed of glassy carbon and made to have characteristics such as a linear expansion coefficient, the surface roughness of a tube inner surface, and the number ratio of oxygen atom to carbon atom (O/C) in the inner surface of the tube or a ratio I (D)/I (G) in the inner surface of the tube [in an equation, I (D) denotes the C-C bond peak value of a diamond structure, and I (G) denotes the C-C bond peak value of a graphite structure], where the above characteristics are controlled so as to improve the inner tube in adhesion to a CVD film component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner tube of a CVD apparatus used in the manufacture of semiconductors, and more particularly to an inner tube of a CVD apparatus which has an improved effect of suppressing generation of particles which cause Si wafer contamination. Things.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of semiconductor devices, silicon produced by chemically reacting one or more compound gases in a gas phase,
A so-called chemical vapor deposition method (hereinafter, referred to as a CVD method) in which silicon nitride or the like is formed on a wafer in a thin film form is used. Here, the inner tube used as a jig is made of Si as shown in FIG.
It is arranged so as to surround the wafer, and plays a role of equalizing the temperature of the wafer in the CVD process and controlling the flow of the reaction gas.

Since the CVD process in the manufacture of Si semiconductor devices is usually in a severe condition of high temperature and in a reactive (corrosive) gas atmosphere such as SiH ₄ , the inner tube also has high heat resistance and corrosion resistance. Further, a certain mechanical strength is required. Conventionally, quartz glass has been used as a material having such heat resistance as to withstand such a severe situation.

Incidentally, Si wafers are required to be manufactured in a cleaner condition, and it is necessary to minimize the attachment of impurities and the like. However, in the above-mentioned CVD method, as shown in FIG. 1, an Si-containing gas 5 is sprayed from above in a sealed container to chemically deposit a Si-containing layer on the surface of the wafer 3. First, the gas component adhered to the inner tube 1 is also attached to the inner surface of the inner tube 1 (hereinafter, the gas component attached to the inner tube may be referred to as a “CVD film component”). The inner tube to which the Si component adheres is not replaced one by one from the viewpoint of productivity and the like, but is repeatedly used. Therefore, the above-mentioned CVD film components are gradually laminated, and eventually peel off from the inner tube main body and adhere to the wafer as particles (fine particle impurities), thereby lowering the product yield.

Conventionally, in order to prevent such generation of particles, the inner tube is regularly cleaned with a chemical such as hydrofluoric acid or nitric acid to remove deposits. The work lowers the production efficiency and increases the production cost. In addition, when the material of the inner tube is quartz glass, it is corroded by hydrofluoric acid or the like during cleaning, and is greatly consumed and has a short life. Therefore, a reduction in production efficiency for replacement and an increase in manufacturing cost are unavoidable.

Recently, as a material for the inner tube,
And SiH used in the production of Si wafers _FourCorrosive gas such as
Corrosion resistance not only to such chemicals at the time of cleaning
Is used as silicon carbide. But yes
Particle generation due to peeling of CVD film components regardless of deviation
At present, the problem of life has not been solved.

Accordingly, the inner tube used in the CVD process of semiconductor manufacturing is required to have excellent heat resistance and corrosion resistance, and to reduce the burden of maintenance such as film removal, the inner tube is deposited on the main body. It is required that the film component has an internal surface that is difficult to peel off.

[0008]

SUMMARY OF THE INVENTION The present inventors have paid attention to the above circumstances, and have been conducting research for the purpose of producing a glassy carbon inner tube having higher performance. First, as a thermosetting resin used for production of a raw material precursor, a degree of curing at 115 ° C. of 10%
A thermosetting resin having a curing property in which the arrival time of (T ₁₀ ) is 5 to 60 minutes and exhibiting a fluidity of 60 mm or more at 100 ° C. in a disk flow test specified in JIS-K6911 is selected. If the resin is formed into a tubular thermosetting resin by a centrifugal molding method, and a method of carbonizing the resin is employed, a glassy carbon tube satisfying the required heat resistance and corrosion resistance can be obtained. I knew that and filed a patent application first.

[0009] However, while further studying the improvement, the above glassy carbon tube was replaced by a CVD for semiconductor production.
When applied to inner tubes used in equipment, CVD
Physical properties of the inner tube in preventing the generation of microparticles due to the separation of the CVD film component adhered and deposited on the inner surface of the inner tube in the process and preventing the contamination of the Si wafer by the microparticles. Was found to be extremely important.

The present invention has been made in view of such problems, and its object is to provide not only excellent heat resistance and corrosion resistance but also adhesion to a CVD film component on the inner surface. An object of the present invention is to provide an inner tube for CVD in which the generation of particles is suppressed by improving the performance and contamination of the Si wafer is suppressed as much as possible.

[0011]

The inner tube for CVD according to the present invention, which has solved the above-mentioned problems, is characterized in that it is made of glassy carbon and has at least one of the following characteristics. .

The coefficient of linear expansion is 2 × 10 ^{-6 to} 3.5 × 10
^-6 , the surface roughness of the inner surface measured by a method according to JIS B0651 and JIS B0601 is 5 to 100 nm, and the oxygen / carbon atomic ratio of the inner surface measured by X-ray photoelectron spectroscopy (O / C) is 0.04 to 0.4, an index I (D) / I (G) representing a chemical bonding state of the inner surface measured by Raman spectroscopy, where I (D) is Represents a peak value indicating a CC bond of a diamond structure, and I (G) represents a peak value indicating a CC bond of a graphite structure.] Is 0.8 to 1.4.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Under the above-described circumstances, the inventors of the present invention have found that S particles originating from particles generated by peeling of a CVD film component laminated on the inner surface of an inner tube.
Intensive research has been conducted with the aim of developing an inner tube for CVD that can minimize i-wafer contamination. As a result, it was found that it is effective to make the inner tube for CVD into glassy carbon, and as a result of examining the properties of glassy carbon from various angles in order to further suppress the generation of particles, the present invention was reached. Things.

In the present invention, glassy carbon is used as a material of an inner tube of a CVD apparatus for semiconductor manufacturing. In particular, in order to enhance adhesion to a laminated CVD film component and suppress generation of particles, It has been found that it is desirable to satisfy the following characteristics.

Hereinafter, the reason for defining each characteristic will be described in detail.

Coefficient of linear expansion; 2 × 10 ^{−6 to} 3.5 × 10 ^{−6 The} present inventors have found that one of the causes of the generation of minute impurities adhering on a Si wafer, so-called particles, is the temperature in a series of CVD steps. We focused on the difference. That is, CVD
In the process, chemical vapor deposition is usually performed at about 500 to 600 ° C., and when the wafer is taken out after the operation is completed, the temperature is lowered to about room temperature. Therefore, when the material of the inner tube and the coefficient of linear expansion of the film component adhering to the inner tube are significantly different, a tensile stress or a compressive stress acts on the film component due to the above-mentioned temperature change. It is considered that interfacial delamination occurs and particles are generated.

In connection with this, when the linear expansion coefficient of quartz or silicon carbide, which has been used as a material of a conventional inner tube for CVD, was investigated, the linear expansion coefficient of a typical CVD film component was Si: 3.9 × 10 ^-6 , Si ₃ N ₄ ; 2.6
Whereas a × 10 ^-6, the coefficient of linear expansion of the quartz or silicon ^{_{carbide, SiO 2; 0.5 × 10 -6}} , SiC; 4.5 ×
10 ^-6 , which was found to be significantly different from those of the CVD film components silicon nitride and polysilicon.

Accordingly, if a material having a coefficient of linear expansion close to that of the CVD film component is used as the material of the inner tube, the CVD film component is peeled off from the inner wall surface of the inner tube even in a situation where a remarkable temperature difference occurs as described above. It was found that the generation of particles could be suppressed effectively.

Therefore, according to the present invention, the linear expansion coefficient of the glassy carbon inner tube is set to a value such as that of Si or Si ₃ N _4.
It is preferable that the coefficient of linear expansion be close to the coefficient of linear expansion of the VD film component. If the coefficients of linear expansion are extremely different from each other, the CVD film component may be separated. Therefore, the coefficient of linear expansion of the inner tube for CVD is 2 × 10 ⁻⁶ or more, preferably 2.5 × 1 ^−6.
And 0 ^-6, also 3.5 × 10 ^-6 or less, and preferably an be suppressed to 2.9 × 10 ^-6 or less.

The linear expansion coefficient is measured according to JIS 1
618 “Method of measuring linear expansion by thermomechanical analysis”
The average linear expansion coefficient at T1 = 25 ° C. and T2 = 600 ° C. was adopted.

In order to obtain an inner tube satisfying the above-mentioned range of the linear expansion coefficient, a powdery or liquid phenol resin is used as a raw material in the production of the glassy carbon inner tube of the present invention, and the inner tube is formed in a nitrogen atmosphere at 800 to 800 μm. 2
It is preferable to fire at 600 ° C, preferably at 1000 to 2000 ° C.

Surface roughness of inner surface of inner tube for CVD: 5 to 100 nm by a method according to JIS B0651 and JIS B0601.

The inventors of the present application have examined the generation factors of particles from still another viewpoint. One of the factors is that the inner surface of the inner tube made of quartz or silicon carbide, which has been used so far, and silicon nitride, It was found that the bonding strength with a CVD film component such as polysilicon was insufficient. Then, as a result of examining a material having good adhesion to the CVD film component, it was found that an inner tube made of substantially only glassy carbon and having an appropriately roughened surface was C
It was confirmed that the adhesive easily adhered firmly to the VD film component, and the effect of suppressing particle generation was high.

Japanese Patent Application Laid-Open No. 9-77534 proposes a material in which the inner surface of a quartz member is coated with glassy carbon, but the surface roughness of the glassy carbon is unknown. Further, the present inventors examined the glassy carbon of 0.8 μm disclosed in the above-mentioned publication, but the effect was insufficient with such a thin film.

Japanese Patent Application Laid-Open No. 10-287495 describes that
A method of making the surface of an inner tube made of silicon carbide smoother, that is, a method of forming a silicon carbide film on the surface of glassy carbon having a smooth surface and then removing the glassy carbon is disclosed. However, in this publication, the surface roughness of silicon carbide, not glassy carbon, is specified, and its purpose is to make the gas flow on the material surface uniform, and it is intended to suppress the generation of particles as in the present invention. Does not prescribe the surface roughness of glassy carbon.

The present inventors have examined the relationship between the surface condition of the glassy carbon inner tube and the adhesiveness with the components of the CVD film. In particular, when the resin of the glassy carbon is in a molten or liquid state, Due to the physical anchor effect, the surface roughness created by carbonizing the "natural surface" as it is,
It has been found that it has the effect of increasing the adhesion to the CVD film components and suppressing the generation of particles.

In the present invention, the preferable surface roughness of the inner tube made of glassy carbon is such that the "natural surface" when the resin of glassy carbon is in a molten or liquid state is carbonized as described above. Specified based on roughness.

If the surface roughness is too small, the above-mentioned adhesiveness is not exhibited and the components of the CVD film are easily peeled off.
According to JIS B0651 and JIS B0601, the surface roughness measured with a stylus having a radius of curvature of 5 μm is 5
nm or more, more preferably 10 n
m or more. If the surface roughness is too large, surface defects increase, and the inner surface of the tube itself tends to fall off. Therefore, the thickness is preferably 100 nm or less, more preferably 60 nm or less.

As a method for obtaining such a preferable surface roughness, as described above, a glassy carbon precursor is formed by centrifugal molding using a liquid resin or a resin which becomes liquid under molding conditions as a raw material. It is also effective to provide groove-like irregularities on the inner surface of the inner tube. In particular, it is desirable that the formation direction of the groove is a direction crossing the length direction of the inner tube, which is considered to be due to the fact that the dimensional change in the length direction of the inner tube is dominant. Can be

Such a groove can be formed by performing a grinding process in a state of a resin molded body during the inner tube manufacturing process, a resin molded body after curing, or a fired product.

An appropriate surface roughness can be obtained by polishing the surface in this manner. However, when polishing is performed, there is a possibility that impurities adhere, work distortion, or processing scratches occur. In order to keep the surface roughness within the above-mentioned preferred range, it is preferable to produce the above-mentioned liquid resin or the like by centrifugal molding.

The oxygen / carbon atom ratio (O /
C): 0.04 to 0.4 by X-ray photoelectron spectroscopy.

The present inventors have further focused on the oxygen content on the inner surface of the inner tube as a factor affecting the adhesion to the CVD film components. In other words, when the oxygen content on the inner surface of the inner tube is extremely low, the inner surface is considered to be chemically stable. In such a state, typical film components such as silicon nitride and polysilicon are removed from the inner tube. It is easily peeled off from the surface and is likely to cause the generation of particles. Therefore, it has been found that the adhesive property can be enhanced by adding a certain amount of oxygen to the inner surface of the inner tube to activate the inner tube and increasing the chemical affinity with the CVD film component.

In the present invention, the oxygen-containing state on the inner surface of the inner tube is defined by the oxygen / carbon atomic ratio (O / C) measured by X-ray photoelectron spectroscopy. / C) value is preferably at least 0.04, more preferably at least 0.06.

On the other hand, when the oxygen on the inner surface of the inner tube is excessive, that is, when the (O / C) value is too large, gases such as CO ₂ and CO are generated in the CVD step, and these gases are used as devices. In addition to causing defects, the CVD film component may be peeled off during degassing, which may promote generation of particles, which is not preferable. Therefore, the (O / C) value is preferably suppressed to 0.4 or less, more preferably 0.2 or less.

The oxygen concentration on the inner surface of the inner tube can be adjusted by the following method. That is, when the oxygen concentration is less than the above specified range, a method of performing a heat treatment in an atmosphere containing an oxidizing gas such as oxygen, an electrochemical oxidation method, or immersion in a chemical solution such as concentrated nitric acid or dichromic acid. The oxygen concentration can be increased by a method or the like. When the oxygen concentration exceeds the above specified range, one of the causes is considered to be insufficient oxygenation due to insufficient oxygen-containing functional groups in the raw material resin. Therefore, in such a case, the oxygen concentration can be adjusted to a specified range by performing heat treatment again at a high temperature.

Index I indicating the chemical bonding state of the inner surface
(D) / I (G) [wherein I (D) represents a peak value indicating a CC bond of a diamond structure in Raman spectroscopy,
I (G) represents a peak value indicating a CC bond of a graphite structure] is 0.8 to 1.4.

The present inventors consider that the chemical bonding state of glassy carbon on the inner surface of the tube is an important factor in order to increase the heat resistance and corrosion resistance of the glassy carbon inner tube and also to increase the effect of suppressing the generation of particles. I found something.

In the present invention, such a chemical bond state of glassy carbon is determined by I (D) / I (G) in Raman spectroscopy.
(Peak value indicating CC bond of diamond structure; I
(D) and a peak value indicating a CC bond of a graphite structure; a ratio of I (G)) as an index.
By setting (D) / I (G) within a certain specific range, it was found that the corrosion resistance and the like were improved and the generation of particles was significantly suppressed.

That is, if the above I (D) / I (G) is too small, a large amount of particles are generated and the corrosion resistance is not preferable. ) Is preferably at least 0.8, more preferably at least 0.9.

When I (D) / I (G) is too small, the glassy carbon on the inner surface of the tube is in a state where graphite is more occupied than diamond and is chemically stable. It is considered that the properties of graphite are developed and the adhesion to the CVD film components is reduced, and the corrosion resistance is also reduced due to the properties of graphite.

Also, when the value of I (D) / I (G) is extremely large, particles are likely to be generated.
(D) / I (G) is preferably suppressed to 1.4 or less, more preferably 1.3 or less. When the value of I (D) / I (G) is extremely large, the CV is extremely unstable on the inner surface of the tube, that is, there are many active structures.
It is considered that such a structure is easily decomposed in the step D, and a large amount of particles are generated.

It should be noted that the I (D) in the Raman spectroscopy described above is used.
The principle of measuring / I (G) is as follows. That is, the carbon test
Raman spectrum of the material comes from the graphite structure
Raman band (G band) is 1580cm^-1Appears and ends
As the crystallinity (degree of graphitization) becomes lower, the G band becomes 160
0cm^-1With high wave number shift to 1360cm ^-1
Near the Raman band (D-bar)
Appears). I (D) / I (G) of the above carbon material is
G and D band signals by Lorentz function
The G band and the D band
It is indicated by the area ratio of the gate.

In order to obtain an inner tube satisfying the above-mentioned range of I (D) / I (G), the phenolic resin molded body is required to have a temperature of 1000 ° C. or more and 2000 ° C. or less in producing the glassy carbon inner tube of the present invention. It is preferable that the inner surface is not mirror-finished.

In the present invention, in order to further improve the adhesion of the glassy carbon inner tube to the CVD film component,
It is preferable to satisfy at least one or more of the characteristics described above, and most preferably to satisfy all of the above characteristics.

As the resin used as a raw material of the glassy carbon inner tube in the present invention, all generally known thermosetting resins such as a phenol resin and a furan resin can be used. However, it is not particularly preferable that the solid resin has a hardening characteristic in which a reaching time (T10) of a hardening degree of 10% at 115 ° C. is 5 to 60 minutes, and a disc-shaped flow defined in JIS-K6911. In the test, a thermosetting resin exhibiting a fluidity of 60 mm or more at 100 ° C., and a liquid resin is a liquid thermosetting resin having a gelation time of 5 to 60 minutes. When the liquid thermosetting resin is used, if the gelation time is less than 5 minutes, the curing proceeds before the generated gas escapes, which may result in poor gas release and cause pore defects or cracks. ,
Conversely, when the gelation time exceeds 60 minutes, the molding takes an extremely long time and, in many cases, contains a large amount of volatile components. It is difficult to obtain. The gel time refers to a gel time measured at 115 ° C. according to a method according to JIS 6901, and a more preferable gel time of the liquid thermosetting resin is 10 to 40 minutes.

Further, it is preferable to use a raw material which is a thermosetting resin at 99% by mass or more of the molding raw material and which does not substantially contain a filler or the like.

The above-mentioned glassy carbon inner tube may be manufactured by a general method for manufacturing glassy carbon.
The method for producing glassy carbon generally comprises roughly the steps of molding the raw material resin and carbonizing the obtained molded body.Preheating is performed before the carbonization step to prevent distortion of the molded body in the carbonization step. May go.

In the production of the inner tube made of glassy carbon, the raw material resin is molded into a cylindrical shape in the above molding step, but the molding method in this case is not particularly limited, and the centrifugal molding method, the injection molding method, the extrusion molding method, and the like. A molding method or the like can be adopted. Among the molding methods, preferably a centrifugal molding method,
The reason is that, in the molding method, the raw material resin in a molten state is caused to flow to the inner surface side of the mold by the centrifugal force and is cured, so that the tube-shaped material is easily molded, the dimensional accuracy of the molded body is high, and the molding is further performed. In some cases, the inner side is open, so that gas can be vented well.

When molding by the centrifugal molding method,
It is recommended to use the centrifugal molding device shown in FIG. In FIG. 2, 6 is preferably cylindrical, and at least one end preferably has an opening through which gas generated during the resin curing reaction can escape. Further, it is desirable that the molding die 6 has a structure that can be rotated at a high speed by a motor or a pulley and that can be divided from the viewpoint of facilitating removal of the manufactured inner tube. As a material of the mold, metal, ceramic, resin, or the like can be used, but metal is preferable in terms of strength and ease of processing.

The resin raw material is loaded into the molding die 6 shown in FIG. Loading of the resin may be performed while the mold is stationary or while the mold is being rotated. The rotational speed of the molding die varies depending on the diameter of the die and the properties and reactivity of the resin, but it is desirable that the rotational speed is set to be twice or more the gravity, preferably 10 G or more.

In the present invention, it is desirable to load the resin raw material 8 into a centrifugal molding die and, while rotating the die, heat the resin to a temperature higher than the temperature at which the curing reaction proceeds. As shown in FIG. Preferably, heating is performed by a heater (heating furnace) 7 arranged on the outer periphery of the mold 6. When the resin raw material 8 has the above properties, the resin is melted by heating,
Compressive force is exerted by centrifugal force generated by rotation of the mold, and is preferably formed into a pipe having a uniform thickness and a uniform wall thickness. Volatile components contained in the resin and gaseous components generated during the molding process can be dissipated from the resin surface not in contact with the mold.

[0053]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention is not limited thereto. Modifications can be made and implemented, all of which are included in the technical scope of the present invention.

(1) Examples relating to coefficient of linear expansion (1-1) Production of raw material resin Thermosetting resins such as phenolic resin and furan resin are suitable as raw materials for glassy carbon. BRL-240 manufactured by Showa Kobunshi Co., Ltd., which is a phenolic resin used in the present invention. Curing characteristics of the above phenolic resin: gel time at 115 ° C. is 50 minutes

(1-2) Molding A centrifugal molding machine equipped with a cylindrical mold having an inner diameter of 325 mm and a length of 2000 mm was used. The centrifugal molding machine used was one in which an electric heater was disposed so as to cover the rotary mold, and was capable of molding while heating. The mold was charged with 6 kg of the resin, and the temperature of the inner surface of the mold was heated to 100 ° C. to melt the resin. While maintaining this temperature, the mold was rotated at a speed of 600 revolutions per minute for 10 hours. Then, it cooled to room temperature and took out the phenolic resin molded object from the metal mold.

The phenolic resin molded product has a thickness of 2.5
mm, a length of 2000 mm, and an outer diameter of 325 mm.

(1-3) Curing The above-mentioned phenol resin molded product was cured at 300 ° C. in air for 200 hours.
Heated for hours. This treatment is performed to prevent thermal deformation of the phenolic resin molded article in the next carbonization step, and may be omitted when there is no fear of deformation.

(1-4) Carbonization Step Five phenol resin molded articles were prepared, and each of them at 800 ° C., 1100 ° C. and 1600 under an inert gas atmosphere.
C., 2100.degree. C., and 2600.degree. C. to carbonize.
In each case, a glassy carbon cylinder having a thickness of 2.1 mm and a length of 1600 mm was obtained, and both ends of the cylinder were cut to obtain a 1000 mm long inner tube for CVD.

(1-5) Evaluation method The linear expansion coefficient is measured according to “Method for measuring linear expansion by thermomechanical analysis” described in JIS1618, and T1 = 25.
° C, T2 = average linear expansion coefficient of 600 ° C.

In addition, the amount of particles generated can be determined by attaching the inner tube to a vertical LP-CVD apparatus and flowing a mixed gas of SiH ₄ and H ₂ at a processing temperature of 650 ° C. to form a polysilicon film on a Si wafer. After formation, the number of particles of 0.2 μm or more on the wafer surface was
r) Measured by Surfscan Model 6220 manufactured by Company.

Table 1 shows the results.

[0062]

[Table 1]

The coefficient of linear expansion is 2 × 10 ^{-6 to} 3.5 × 10 ^-6
Experiment No. within the range of No. In Nos. 1 to 5, the generation of particles adhering to the wafer surface was significantly suppressed. On the other hand, in the inner tube made of quartz or silicon carbide having a coefficient of linear expansion outside the specified range of the present invention, a large amount of particles were generated.

(2) Example of Surface Roughness (2-1) Production of Raw Material Resin As in the case of Example (1), a commercially available phenol resin, BRL-240 manufactured by Showa Kobunshi, was used.

The phenol resin and the catalyst, tetramethylenehexamine (HMT), were mixed in the proportions shown in Table 2 below, and reacted at 65 ° C. for 6 hours. Then, heating was continued under vacuum to obtain a water content of 5 mass. %.

(2-2) Molding / Curing Molding / curing was performed in the same manner as in Example (1) except that the rotation time during molding was set to 5 hours.

(2-3) Carbonization treatment step
It was carbonized by heat treatment at 600 ° C. A glassy carbon cylinder having a thickness of 2.1 mm and a length of 1600 mm was obtained, and both ends of each cylinder were cut to obtain a 1000 mm long inner tube for CVD.

(2-4) Evaluation Method As in the case of Example (1), a polysilicon film was formed on a Si wafer, and the amount of generated particles was measured.
Table 2 shows the results.

[0069]

[Table 2]

The experiment No. Experiment Nos. 10 to 12 are Nos.
Prepare the same inner tube as in 6, and use diamond slurries with different particle sizes on the inner surface,
Polishing is performed by a general method.

The center line surface roughness (Ra) was measured using a stylus type roughness meter manufactured by Rank Taylor Co., Ltd., and the surface in the direction parallel to the length direction of the inner tube in a region free from surface flaws generated during handling or the like. The roughness was measured according to JIS B 0651 and J
According to IS B0601, the measurement was performed using a stylus having a radius of curvature of 5 μm.

From the results shown in Table 2, in the case of Experiment No. in which Ra was within the range of the present invention. It can be seen that particles Nos. 6 to 10 can significantly reduce particles as compared with conventional quartz or silicon carbide inner tubes.

On the other hand, in Experiment No. In the case of No. 11, many particles were generated, which is considered to be due to the fact that Ra was below the specified range of the present invention and the surface was too smooth, so that the effect of physically bonding with the CVD film component was small.
Experiment No. Although a large number of particles were generated even in the case of No. 12, it is conceivable that microcracks are generated during polishing as a cause of this.

(2-5) Embodiment in which Irregularities are Provided on Tube Inner Surface In the present invention, experiments were also conducted on a case where the surface roughness was adjusted by providing irregularities on the inner tube inner surface. That is, in the same manner as in the case of the example relating to the surface roughness, a raw material resin is manufactured, and molded, cured, and carbonized.
Grinding processing for forming grooves on the surface was performed in the following experiment No.
Experiment No. 13 was not performed. In No. 14, after the resin molded body was molded, Experiment No. 14 was performed. In the test 15, after curing, the experiment N
o. In No. 16, the process was performed after the carbonization process. The grinding process is
Each test was performed while rotating the cylindrical member around the center of the cylinder in the length direction.

The center line surface roughness (Ra) was measured in the same manner as described above by using a stylus type roughness meter manufactured by Rank Taylor Co., Ltd., and the surface roughness in a direction parallel to the length direction of the inner tube was determined as J.
The measurement was performed according to ISB0651 and JIS B0601.

Table 3 shows the measurement results of the respective surface roughnesses.

[0077]

[Table 3]

From Table 3, it can be seen from Experiment Nos. 1
In Nos. 4 to 16, the surface roughness is equivalent to that of the inner tube made of quartz or silicon carbide, but the generation of particles is significantly reduced by providing groove-like irregularities in a direction perpendicular to the length direction of the tube. I was able to.

(3) Example on Surface Oxygen Concentration (3-1) Production of Raw Material Resin As in Example (1), a commercially available phenol resin, BRL-240, manufactured by Showa Kobunshi was used.

Further, 100 parts by mass of a phenol resin and 8 parts by mass of tetramethylenehexamine (HMT) as a catalyst were mixed and reacted at 65 ° C. for 6 hours. Then, heating was continued under vacuum, and the water content was 5 mass% or less. Dehydrated until it became.

(3-2) Molding / Curing Molding / curing was performed in the same manner as in Example (1) except that the rotation time during molding was set to 5 hours.

(3-3) Carbonization Step Four phenolic resin molded articles were prepared, and each of them was heated to 1000 ° C., 1500 ° C., and 2000 ° C. in an inert gas atmosphere.
C. and carbonized by heat treatment at 2500.degree. In each case, a glassy carbon cylinder having a thickness of 2.1 mm and a length of 1600 mm was obtained.
mm inner tube for CVD was obtained.

Further, a tube carbonized at 2500 ° C. was separately prepared, and was placed in a 0.1 mol / l NaOH aqueous solution.
Electrolytic oxidation was performed for 5 minutes or 20 minutes at 0 mA / cm ² .

(3-4) Evaluation Method The oxygen / carbon atom ratio was measured with an X-ray photoelectron spectrometer after the inner tube obtained by the carbonization treatment was ultrasonically washed in ethanol for about 5 minutes.

The analysis conditions of the X-ray photoelectron spectrometer used for the measurement are as follows.

Analyzer: PHI manufactured by Perkin-Elmer
5400MC X-ray photoelectron spectrometer X-ray source: MgKα X-ray output: 400 W (15 kV, 26.7 mA) Analysis area: 1.1 mmφ Angle between detector and sample: 45 ° Ar ⁺ Sputter rate: 20 Å in terms of SiO ₂ / Min (1.5 kV / 25 mA) All sputtering depths in the text are shown in terms of SiO ₂ .

Table 4 shows the production conditions, XPS analysis results, and evaluation results.

[0088]

[Table 4]

The O / C tends to decrease as the carbonization temperature is increased. This is because oxygen atoms in the phenol resin as a raw material are more easily desorbed by thermal decomposition as the temperature is increased. Conceivable.

From Table 4, it can be seen that Experiment No. 17-19,21
Satisfies the numerical range of O / C defined in the present invention, and it has been found that particles generated on the wafer can be significantly reduced as compared with the conventional inner tube made of quartz or silicon carbide. On the other hand, in experiment no. 20 is O /
C was less than the prescribed range of the present invention, resulting in generation of many particles.

Also, in Experiment No. As shown in FIG. 21, even when carbonization was performed at a high temperature, particles could be significantly reduced by performing appropriate electrolytic oxidation. However, Experiment No. As shown in FIG. 22, when the electrolytic oxidation was performed excessively, more particles were generated than those made of quartz or silicon carbide.

(4) Example relating to crystallinity (4-1) Production of raw material resin In the present invention, PL-4804 manufactured by Gunei Chemical Co., Ltd., which is a commercially available liquid phenol resin, was used as a raw material of glassy carbon.

Curing characteristics of the above liquid phenolic resin: 11
The gel time at 5 ° C. is 40 minutes.
Parts by weight and tetramethylenehexamine (H
MT) was mixed and stirred at 65 ° C. for 1 hour to obtain a forming raw material.

(4-2) Molding / Curing Molding / curing was performed in the same manner as in Example (1) except that the rotation time during molding was set to 5 hours.

(4-3) Carbonization Step Four phenolic resin molded articles were prepared, and each of them was placed in an inert gas atmosphere at 1000 ° C., 1500 ° C., and 2000 ° C.
C. and carbonized by heat treatment at 3000.degree. In each case, a glassy carbon cylinder having a thickness of 2.1 mm and a length of 1600 mm was obtained.
A 0 mm inner tube for CVD was obtained.

[0096] It is to be noted that an experiment No. Experiment No. 27 is Experiment No. 27.
The inner surface of the inner tube manufactured under the same conditions as in No. 23 was mirror-finished by precision polishing.

(4-4) Evaluation Method As described above, the Raman spectrum of the carbon sample was such that the Raman band (G band) derived from the graphite structure was 158.
Appeared to 0 cm ^-1, crystalline as the (degree of graphitization) is lowered, together with the G band is high wavenumber shifts to 1600 cm ^-1, the Raman bands (D-band) near 1360 cm ^-1
Appears.

In the present invention, the signals of the G band and the D band are curve-fitted using the Lorentz function to determine the area value, and the area ratio between the G band and the D band is calculated as I (D) / I (G).
Was evaluated.

The setting conditions of the Raman spectrophotometer used for this measurement are as follows.

Apparatus: NR-1000 type laser Raman spectrophotometer manufactured by JASCO Corporation Measurement method: 90 degree scattering method Excitation light source: Argon ion laser Excitation wavelength: 488.0 nm Excitation light output: 300 mW Measurement area: 1000-2000 cm ^-1 resolution: about 8 cm ^{-1 The} production conditions and the evaluation results are shown in Table 5.

[0101]

[Table 5]

Experiment No. 23 to 25 satisfied I (D) / I (G) defined in the present invention, and the generation of particles could be made very small. In contrast, experiment N
o. In No. 26, I (D) / I (G) did not satisfy the specified range of the present invention, and the result was that particles were generated equal to or more than when quartz or silicon carbide was used. The reason is that when I (D) / I (G) is small, that is, when the ratio of CC double bonds is high, the chemical interaction with the CVD film component is small, and the adhesion strength of the film is low. It is thought that it will decrease.

Further, in Experiment No. At 27, I (D) / I
(G) exceeds the specified range of the present invention, and also in this case, particles were generated to the same extent as in the case of quartz or silicon carbide. This is presumed to be due to a structural disorder due to polishing or a minute crack caused by the structural disorder, which contributes to peeling of the film.

[0104]

The present invention is constituted as described above. By using glassy carbon as a material, the present invention has excellent heat resistance and corrosion resistance, and furthermore, it is possible to prevent the generation of particles of a CVD film component. An inner tube for CVD in which peeling hardly occurs was provided. Further, the properties of the inner tube made of glassy carbon include a coefficient of linear expansion, a surface roughness of the inner surface of the tube, an oxygen content concentration on the inner surface of the tube, or an index I (D) / I representing a chemical bonding state of the inner surface of the tube.
By defining (G), it was possible to provide an inner tube for CVD in which the effect of suppressing the generation of particles was further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional explanatory view illustrating a CVD apparatus for manufacturing a semiconductor.

FIG. 2 is a schematic cross-sectional explanatory view illustrating a centrifugal molding apparatus that can be used for manufacturing a product of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner tube 2 Outer tube 3 Si wafer 4 Wafer support board 5 Raw material gas 6 Mold 7 Heater 8 Resin raw material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G032 AA07 4K030 CA04 GA01 KA08 KA46 5F045 BB14 DP19 DQ05 EC02 EC05 EF02

Claims (5)

[Claims] 1. An inner tube for CVD comprising glassy carbon. 2. A coefficient of linear expansion of 2 × 10 ^{−6 to} 3.5 × 10.
^The inner tube for CVD according to claim 1, which is ^-6 . 3. JIS B0651 and JIS B060
The surface roughness of the inner surface measured by the method according to 1 is 5 to
The inner tube for CVD according to claim 1 or 2, which has a thickness of 100 nm. 4. The CVD according to claim 1, wherein the oxygen / carbon atom ratio (O / C) of the internal surface is 0.04 to 0.4 as measured by X-ray photoelectron spectroscopy. For inner tube. 5. An index I (D) / I (G) representing the state of chemical bonding on the inner surface, as measured by Raman spectroscopy, wherein I (D) is a peak value indicating a CC bond of a diamond structure. Represents
I (G) represents a peak value indicating a CC bond of a graphite structure] is 0.8 to 1.4. The inner tube for CVD according to any one of claims 1 to 4.