JP3457257B2 - Inner tube for CVD - Google Patents

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 for manufacturing a semiconductor, and more particularly to an inner tube of a CVD apparatus having a further enhanced effect of suppressing generation of particles causing contamination of Si wafers. It is a thing.

[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) for forming a thin film of silicon nitride or the like on a wafer is adopted. The inner tube used as a jig here is made of Si as shown in FIG.
It is arranged so as to surround the wafer and plays a role of uniformizing the temperature of the wafer in the CVD process and controlling the flow of the reaction gas.

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

By the way, the Si wafer is required to be manufactured in a cleaner state, and it is necessary to avoid adhesion of impurities and the like as much as possible. However, in the above-mentioned CVD method, as shown in FIG. 1, the Si-containing gas 5 is sprayed from above in a sealed container in order to chemically deposit the Si-containing layer on the surface of the wafer 3, and if the gas component is only on the wafer. Instead, it also adheres to the inner surface of the inner tube 1 (hereinafter, the gas component adhered to the inner tube may be referred to as "CVD film component"). The inner tube to which the Si component is attached is not replaced one by one from the viewpoint of productivity and is repeatedly used. Therefore, the above CVD film components are gradually laminated and finally peeled off from the inner tube main body and adhered to the wafer as particles (fine particle impurities), thereby lowering the product yield.

Conventionally, in order to prevent the generation of such particles, the inner tube is regularly washed with a chemical solution such as hydrofluoric acid or nitric acid to remove deposits, but it is frequently washed. The work reduces production efficiency and causes increase in manufacturing cost. Further, when the material of the inner tube is quartz glass, it is corroded by hydrofluoric acid or the like at the time of cleaning and is consumed greatly and has a short life. Therefore, it is unavoidable that production efficiency and replacement cost for replacement are increased.

Recently, as a material for the inner tube
SiH used during Si wafer manufacturing _FourCorrosive gas such as
Not only corrosion resistance against chemicals during such cleaning
Silicon carbide is used as having. But yes
Even if there is a gap, particle generation due to peeling of CVD film components
The problem of being raw has not yet been solved.

Therefore, excellent heat resistance and corrosion resistance are required for the inner tube used in the CVD process of semiconductor manufacturing, and the CVD deposited on the main body in order to reduce the burden of maintenance such as film removal. 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 in anticipation of the manufacture of a glassy carbon inner tube having excellent performance for some time. As a thermosetting resin used for the production of the raw material precursor, the curing degree at 115 ° C. is 10%.
A thermosetting resin having a curing property such that the arrival time of (T ₁₀ ) is 5 to 60 minutes and further showing a fluidity of 60 mm or more at 100 ° C. in a disc type flow test specified in JIS-K6911 is selected. If a tube-shaped thermosetting resin molded body is formed from the resin by a centrifugal molding method and carbonization is performed on the resin, a glassy carbon tube satisfying the required heat resistance and corrosion resistance can be obtained. Knowing that, I applied for a patent first.

After that, however, while further improvement research was being conducted, the glassy carbon tube was subjected to CVD for semiconductor production.
When applied to the inner tube used in the equipment, CVD
In order to prevent the generation of microparticles due to the peeling of the CVD film component adhered and deposited on the inner surface of the inner tube in the step and prevent the contamination of the Si wafer by the microparticles, the physical characteristics of the inner tube Has been found to be extremely important.

The present invention has been made by paying attention to such a problem, and its purpose is not only to have excellent heat resistance and corrosion resistance, but also to adhere the inner surface to a CVD film component. Another object of the present invention is to provide an inner tube for CVD in which the property is improved, the generation of particles is suppressed, and the contamination of the Si wafer is suppressed as much as possible.

[0011]

An inner tube for CVD according to the present invention, which has solved the above-mentioned problems, is characterized by being made of glassy carbon and having one or more 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 the method according to JIS B0651 and JIS B0601 is 5 to 100 nm, the oxygen / carbon atom number ratio of the inner surface measured by X-ray photoelectron spectroscopy (O / C) is 0.04 to 0.4, and the index I (D) / I (G) [in the formula, I (D) is a chemical bond state of the inner surface measured by Raman spectroscopy] Represents a peak value showing a C—C bond of the diamond structure, and I (G) represents a peak value showing a C—C bond of the graphite structure] is 0.8 to 1.4.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Under the circumstances as described above, the inventors of the present invention used S due to particles generated by peeling of a CVD film component laminated on the inner surface of an inner tube.
We conducted intensive research in anticipation of the development of an inner tube for CVD that can reduce i-wafer contamination as much as possible. As a result, it was found that it is effective to use glassy carbon for the inner tube for CVD, and the characteristics of glassy carbon were examined from various angles in order to further suppress the generation of particles. As a result, the present invention was conceived. It is a thing.

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

The reasons for defining each characteristic will be described in detail below.

Linear expansion coefficient; 2 × 10 ^{−6 to} 3.5 × 10 ^{−6 The} present inventors have found that one of the causes of generation of minute impurities, so-called particles, attached to a Si wafer is the temperature in a series of CVD steps. 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 work is completed, the temperature is lowered to about room temperature. Therefore, when the material of the inner tube and the linear expansion coefficient of the film component attached to the inner tube are significantly different, tensile stress or compressive stress acts on the film component due to the above temperature change, and the inner surface of the inner tube and the film component are separated. It is considered that the interfacial peeling occurs at and the particles are generated.

In this regard, when the linear expansion coefficient of quartz or silicon carbide which has been used as a material for the conventional inner tube for CVD is investigated, the linear expansion coefficient of a typical CVD film component is 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 ×
It was 10 ⁻⁶ , and it was found that it was remarkably different from that of silicon nitride and polysilicon, which are CVD film components.

Therefore, if a material having a linear expansion coefficient close to that of the CVD film component is used as the material of the inner tube, the CVD film component is separated from the inner wall surface of the inner tube even in the situation where a significant temperature difference occurs as described above. It has been found that it is difficult to do so and the generation of particles can be effectively suppressed.

Therefore, in the present invention, the linear expansion coefficient of the glass-like carbon inner tube is set to the above-mentioned C such as Si or Si ₃ N _4.
It is preferable to approach the linear expansion coefficient of the VD film component, and if the linear expansion coefficients of the two are extremely different, the CVD film component may peel off. Therefore, the coefficient of linear expansion of the inner tube for CVD is 2 × 10 ⁻⁶ or more, preferably 2.5 × 1.
It is set to 0 ^-6 or more and to 3.5 × 10 ^-6 or less, preferably 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 of T1 = 25 ° C. and T2 = 600 ° C. was adopted.

In order to obtain an inner tube satisfying the above range of the coefficient of linear expansion, 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 temperature is 800 to 800 in a nitrogen atmosphere. Two
It is preferable to bake at 600 ° C, preferably 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 investigated the factors causing the particles from another point of view. 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 or It was found that the adhesive strength with the CVD film component such as polysilicon is insufficient. Then, as a result of studying a material having good adhesiveness with the CVD film component, it was found that the inner tube made of only glassy carbon has a moderately rough surface.
It was confirmed that the VD film component was easily adhered firmly and the particle generation suppressing effect was high.

Incidentally, Japanese Patent 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 inventors examined the 0.8 μm glassy carbon disclosed in the above publication, but the effect was insufficient with such a thin film.

Further, in Japanese Patent Laid-Open No. 10-287495,
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 is specified instead of glassy carbon, and the purpose is to make the gas flow uniform on the surface of the material, and to suppress the generation of particles as in the present invention. Does not specify the surface roughness of glassy carbon.

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

In the present invention, the preferable surface roughness of the glass-like carbon inner tube is the surface formed by carbonizing the "natural surface" when the glass-like carbon resin is in the molten or liquid state as described above. It was defined based on the roughness.

If the surface roughness is too small, the above-mentioned adhesiveness is not exhibited and the CVD film component is easily peeled off.
According to JIS B0651 and JIS B0601, the surface roughness measured using a stylus with a radius of curvature of 5 μm is 5
nm or more, more preferably 10 n
It is m or more. Further, if the surface roughness is too large, the number of surface defects increases 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 liquid glass resin or a resin which is in a liquid state under molding conditions is used as a raw material, and a glassy carbon precursor is formed by centrifugal molding. It is also effective to apply groove-shaped irregularities to the inner surface of the inner tube. In particular, it is desirable that the groove is formed in a direction that intersects the length direction of the inner tube. This is because the dimensional change in the length direction of the inner tube is dominant. To be

Further, such a groove can be formed by grinding the resin molded body in the inner tube manufacturing process, the resin molded body after curing, or the fired product.

An appropriate surface roughness can be obtained by polishing the surface in this way. However, when polishing is performed, there is a risk of adhesion of impurities, processing strain, or processing scratches. In order to bring the surface roughness of the above into the above-mentioned preferable range, it is preferable to manufacture the above liquid resin or the like by a centrifugal molding method.

Oxygen / carbon atom number 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 component. That is, 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 used as the inner tube. It is easily peeled off from the surface and is likely to cause particles. Therefore, it has been found that the adhesiveness can be enhanced by making the inner surface of the inner tube contain a certain amount of oxygen to activate the inner tube to enhance the chemical affinity with the CVD film component.

Therefore, in the present invention, such an oxygen-containing state on the inner surface of the inner tube is defined by the oxygen / carbon atom number ratio (O / C) measured by X-ray photoelectron spectroscopy. / C) value is preferably 0.04 or more, more preferably 0.06 or more.

On the other hand, when oxygen is excessive on the inner surface of the inner tube, that is, when the (O / C) value is too large, gases such as CO ₂ and CO are generated in the CVD process, and these gases are used as a device. Is not preferable because it may not only cause the defects of 1) but also promote the generation of particles by exfoliating the CVD film components during degassing. Therefore, the (O / C) value is preferably 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 specified range, a method of 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. Further, when the oxygen concentration exceeds the above specified range, it is considered that one of the causes is due to the oxygen-containing functional group in the raw material resin remaining due to insufficient carbonization treatment. Therefore, in such a case, the oxygen concentration can be adjusted within the specified range by performing heat treatment again at a high temperature.

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

The present inventors have found that the chemical bonding state of the glassy carbon on the inner surface of the tube is an important factor for enhancing the heat resistance and corrosion resistance of the glassy carbon inner tube and enhancing the effect of suppressing particle generation. I found out.

In the present invention, the chemical bonding state of such glassy carbon is determined by I (D) / I (G) in Raman spectroscopic analysis.
(Peak value showing C—C bond of diamond structure; I
(D) and the peak value showing the C—C bond of the graphite structure; the ratio of I (G)) as an index.
It has been found that by setting (D) / I (G) within a certain specific range, the corrosion resistance and the like are improved and the generation of particles is significantly suppressed.

That is, when the above I (D) / I (G) is too small, a large amount of particles are generated and the corrosion resistance is also unfavorable. Therefore, in the present invention, the above I (D) / I (G). ) Is preferably 0.8 or more, more preferably 0.9 or more.

When I (D) / I (G) is too small, the glassy carbon on the inner surface of the tube is in a state of being more graphite-based than diamond-based, so that it is chemically stable. It is considered that the properties of graphite are developed, the adhesion to the CVD film component is lowered, and the corrosion resistance is also lowered 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 1.4 or less, more preferably 1.3 or less. When the value of I (D) / I (G) is remarkably large, there are many chemically unstable or active structures on the inner surface of the tube.
It is considered that such a structure is easily decomposed in the D step and a large amount of particles are generated.

I (D) in the above Raman spectroscopic analysis method
The measurement principle of / I (G) is as follows. That is, carbon test
Raman spectrum of the material comes from the graphite structure
Raman band (G band) is 1580 cm^-1Appearing in
As the crystallinity (graphitization degree) becomes lower, the G band becomes 160
0 cm^-1High wave number shift to 1360 cm ^-1
Raman band (D
Appears). I (D) / I (G) of the above carbon material is
The signals of G band and D band of
Area fitting to find the area value, and the G band and D band
It is indicated by the area ratio.

In order to obtain an inner tube satisfying the above range of I (D) / I (G), a phenol resin molding is used in the production of the glassy carbon inner tube of the present invention at a temperature of 1000 ° C. or higher and 2000 ° C. or lower. It is preferable that the inner surface is baked, and 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 that at least one of the characteristics described above is satisfied, and most preferably, all of the above characteristics are satisfied.

As the resin used as the raw material for the glassy carbon inner tube in the present invention, all of the generally known thermosetting resins such as phenol resin and furan resin can be used, and are limited. However, it is particularly preferable that the solid resin has a curing property such that the arrival time (T10) at a curing degree of 10% at 115 ° C. is 5 to 60 minutes, and the disc type flow defined in JIS-K6911. In the test, it is a thermosetting resin showing 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 gelling time is less than 5 minutes, curing may proceed before the generated gas escapes, resulting in poor gas release and causing pore defects or cracks. ,
On the other hand, if the gelation time exceeds 60 minutes, it takes an extremely long time for molding and, in many cases, contains a large amount of volatile components, so that the amount of gas generated during molding is large and a molded product with a good surface condition is obtained. Hard to get. The gelling time means a gelling time measured at 115 ° C. by a method according to JIS 6901, and a more preferable gelling time of the liquid thermosetting resin is 10 to 40 minutes.

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

The glass-like carbon inner tube may be manufactured by a general glass-like carbon manufacturing method.
The method for producing glassy carbon generally consists of a raw resin molding step and a carbonization step of the obtained molded body, and preheating is performed before the carbonization step in order to prevent distortion of the molded body in the carbonization step. You can go.

In the production of the glassy carbon inner tube, the raw material resin is molded into a cylindrical shape in the above-mentioned molding step, but the molding method in this case is not particularly limited, and it may be a centrifugal molding method, an injection molding method or an extrusion method. A molding method or the like can be adopted. Of 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 molding die by the centrifugal force to be hardened, so that the tubular material can be easily molded and the dimensional accuracy of the molded body is high, Since the inner surface is open at times, it is possible to satisfactorily degas.

When molding by the above 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 thereof preferably has an opening so that the gas generated during the resin curing reaction escapes to the outside. Furthermore, it is desirable that the molding die 6 has a dividable structure from the viewpoint that it can be rotated at a high speed by a motor or a pulley and that the manufactured inner tube can be easily taken out. As the material of the mold, metal, ceramic, resin or the like can be used, but metal is preferable in terms of strength and workability.

The resin raw material is loaded into the molding die 6 shown in FIG. The resin may be loaded while the mold is stationary or while being rotated. The rotation 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 to set it so that a gravity of twice the gravity or more, preferably 10 G or more, is generated.

In the present invention, it is desirable to load the resin raw material 8 into the mold for centrifugal molding and to heat the resin at a temperature not lower than the temperature at which the curing reaction proceeds while rotating the mold. As shown in FIG. It is preferable to heat with 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,
A centrifugal force generated by the rotation of the mold exerts a compressive force, which is preferable because it is formed into a pipe shape with a uniform wall thickness and a substantially constant inner diameter. Volatile components contained in the resin and gaseous components generated in 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 may be appropriately applied within a range compatible with the gist of the preceding and the following. Modifications can be made and implemented, and all of them are included in the technical scope of the present invention.

(1) Example concerning linear expansion coefficient (1-1) Production of raw material resin As a raw material of glassy carbon, thermosetting resin such as phenol resin or furan resin is suitable, and in this example, it is commercially available. BRL-240 manufactured by Showa High Polymer Co., Ltd., which is a phenol resin of Curing characteristics of the above-mentioned phenol resin: gelation time at 115 ° C for 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 was equipped with an electric heater so as to cover the rotary mold, and was capable of molding while heating. The mold was filled 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 rpm for 10 hours. Then, it cooled to room temperature and took out the phenol resin molded body from the metal mold | die.

The phenol resin molding 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 body was subjected to 200 at 300 ° C. in air.
Heat treated for hours. This treatment is performed to prevent thermal deformation of the phenol resin molded body in the next carbonization step, and can be omitted if there is no risk of deformation.

(1-4) Carbonization Step Five pieces of the above-mentioned phenol resin molded body were prepared, respectively, in an inert gas atmosphere, 800 ° C., 1100 ° C., 1600.
It was carbonized by heat treatment at 2 ° C, 2100 ° C, and 2600 ° C.
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 this 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 of measuring linear expansion by thermomechanical analysis" described in JIS1618, and T1 = 25.
The average linear expansion coefficient of T2 = 600 ° C was adopted.

As for the amount of particles generated, the inner tube was attached to a vertical LP-CVD apparatus, and a mixed gas of SiH ₄ and H ₂ was caused to flow at a processing temperature of 650 ° C. to form a polysilicon film on a Si wafer. After forming, the number of particles of 0.2 μm or more on the wafer surface
r) manufactured by Surfscan Model 6220 manufactured by Surfscan.

The results are shown in Table 1.

[0062]

[Table 1]

The coefficient of linear expansion is 2 × 10 ^{-6 to} 3.5 × 10 ^-6
Experiment No. within the range of Nos. 1 to 5 were able to remarkably suppress the generation of particles adhering to the wafer surface. On the other hand, many particles were generated in the inner tube made of quartz or silicon carbide whose linear expansion coefficient is out of the specified range of the present invention.

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

This phenolic resin and tetramethylenehexamine (HMT) which is a catalyst were mixed in the proportions shown in Table 2 below, reacted at 65 ° C. for 6 hours, and then heated under vacuum to give a moisture content of 5 mass. It was dehydrated until it became less than%.

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

(2-3) Carbonization treatment step The above-mentioned phenol resin molded body is subjected to 1 step in an inert gas atmosphere.
It heat-processed at 600 degreeC and carbonized. 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 particles generated was measured.
The results are shown in Table 2.

[0069]

[Table 2]

Experiment No. Experiment Nos. 10 to 12 are Nos.
Prepare an inner tube similar to 6 and use diamond slurries with different particle sizes on the inner surface of the inner tube,
The polishing is performed by a general method.

The center line surface roughness (Ra) was measured by using a stylus type roughness meter manufactured by Lanktera Co., Ltd., and the surface in the direction parallel to the length direction of the inner tube in the area without surface flaws caused during handling. Roughness is 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, Experiment No. in which Ra is within the range of the present invention is shown. It can be seen that Nos. 6 to 10 can significantly reduce particles as compared with the conventional inner tube made of quartz or silicon carbide.

On the other hand, in Experiment No. Although a large number of particles were generated in No. 11, it is considered that this is because Ra is below the specified range of the present invention and the surface is too smooth, so that the physical adhesion effect with the CVD film component is small.
In addition, the experiment No. A large number of particles were generated even in No. 12, but it is conceivable that minute cracks were generated during polishing as the cause.

(2-5) Examples in which unevenness is provided on the inner surface of the tube Further, in the present invention, an experiment was conducted also when the surface roughness was adjusted by providing unevenness on the inner surface of the inner tube. That is, as in the case of the examples relating to the surface roughness, a raw material resin is produced, and molding, curing and carbonization are performed,
Grinding processing for forming a groove on the surface was performed by the following experiment No.
Experiment No. 13 was not performed. In No. 14, after molding the resin molded body, the experiment No. After curing in No. 15, further experiment N
o. In No. 16, it was performed after the carbonization process. The grinding process is
The measurement 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 by using a stylus type roughness meter manufactured by Lanktera, as in the above case, and the surface roughness in the direction parallel to the length direction of the inner tube was measured by J
It 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, the experiment No. which is ground is shown. 1
Nos. 4 to 16 have surface roughness equivalent to that of an inner tube made of quartz or silicon carbide, but by forming groove-shaped irregularities in a direction orthogonal to the length direction of the tube, particle generation is significantly reduced. I was able to.

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

Further, 100 parts by mass of a phenol resin and 8 parts by mass of tetramethylenehexamine (HMT) as a catalyst were mixed, reacted at 65 ° C. for 6 hours, and then continued to be heated under vacuum to obtain a water content of 5 mass% or less. It was dehydrated until.

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

(3-3) Carbonization Treatment Step Four above-mentioned phenol resin moldings were prepared and were respectively placed in an inert gas atmosphere at 1000 ° C., 1500 ° C. and 2000 ° C., respectively.
C. and 2500.degree. C. to heat and 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 this cylinder were cut to a length of 1000 mm.
A mm inner tube for CVD was obtained.

Separately, a tube carbonized at 2500 ° C. was prepared and placed in a 0.1 mol / l NaOH aqueous solution.
The electrolytic oxidation was performed for 5 minutes or 20 minutes under the condition of 0 mA / cm ² .

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

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

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

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

[0088]

[Table 4]

The O / C tends to decrease as the carbonization temperature is raised, but this is because the oxygen atom in the raw material phenol resin is more easily desorbed by thermal decomposition as the temperature is increased. Conceivable.

From Table 4, the experiment No. 17-19,21
It satisfies the O / C numerical range specified in the present invention, and it was found that the 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 below the specified range of the present invention, resulting in many particles being generated.

Experiment No. As shown in FIG. 21, even when the carbonization treatment was performed at a high temperature, it was possible to significantly reduce the particles by performing an appropriate electrolytic oxidation. However, in Experiment No. As shown in 22, when excessive electrolytic oxidation was performed, more particles were generated than those made of quartz or silicon carbide.

(4) Example for Crystallinity (4-1) Production of Raw Material Resin As a raw material of glassy carbon, in the present invention example, commercially available liquid phenol resin PL-4804 manufactured by Gunei Chemical Co., Ltd. was used.

Curing characteristics of the above liquid phenol resin: 11
Gelation time at 5 ° C 40 minutes This phenolic resin 100
Parts by mass and tetramethylene hexamine (H
(MT) 5 parts by mass were mixed and stirred at 65 ° C. for 1 hour to obtain a molding 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 5 hours.

(4-3) Carbonization step Four above-mentioned phenol resin moldings were prepared, and were respectively placed in an inert gas atmosphere at 1000 ° C., 1500 ° C. and 2000 ° C., respectively.
It was heat-treated at 3000C and 3000C for carbonization. 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 this cylinder were cut to a length of 100 mm.
A 0 mm inner tube for CVD was obtained.

Experiment No. Experiment No. 27 is No.
The inner surface of the inner tube manufactured under the same conditions as No. 23 was mirror-finished by precision polishing.

(4-4) Evaluation Method As described above, in the Raman spectrum of the carbon sample, the Raman band (G band) derived from the graphite structure is 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 area values are obtained by curve-fitting the signals of the G band and D band by the Lorentz function, and the area ratio of this G band and D band is I (D) / I (G).
Evaluated as.

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 Manufacturing conditions and evaluation results are shown in Table 5.

[0101]

[Table 5]

Experiment No. Nos. 23 to 25 satisfied I (D) / I (G) defined in the present invention, and generation of particles could be minimized. In contrast, experiment N
o. In No. 26, I (D) / I (G) was less than the specified range of the present invention, and the result was that particles were generated in the same amount or more than in the case of using quartz or silicon carbide. The reason is that when I (D) / I (G) is small, that is, when the ratio of C—C double bonds is high, the chemical interaction with the CVD film component is small, and therefore the adhesion strength of the film is low. It is possible to decrease.

Experiment No. 27, I (D) / I
(G) exceeds the specified range of the present invention, and in this case, particles are generated to the same extent as in the case of quartz or silicon carbide. It is presumed that this is because the structural disorder due to polishing or the minute cracks caused by the structural disorder contribute to the peeling of the film.

[0104]

EFFECTS OF THE INVENTION The present invention is configured as described above, and by using glassy carbon as a material, it has excellent heat resistance and corrosion resistance, and further, a CVD film component that causes particles is generated. It was possible to provide an inner tube for CVD that is unlikely to peel. Further, as the characteristics of the inner glass tube made of glassy carbon, an index I (D) / I indicating the linear expansion coefficient, the surface roughness of the inner surface of the tube, the oxygen content concentration of the inner surface of the tube, or the chemical bonding state of the inner surface of the tube.
By defining (G), it was possible to provide an inner tube for CVD with a higher effect of suppressing particle generation.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional explanatory view illustrating a CVD apparatus for semiconductor production.

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

[Explanation 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 materials

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-218916 (JP, A) JP-A-9-7954 (JP, A) JP-A-2-192411 (JP, A) JP-A-2000-159575 (JP, A) JP 2001-335366 (JP, A) JP 2001-334539 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 35/52 C23C 16/00- 16/56 H01L 21/205

Claims (5)

(57) [Claims] 1. An inner tube for CVD, which is made of glassy carbon. 2. A linear expansion coefficient of 2 × 10 ^{−6 to} 3.5 × 10.
^The inner tube for CVD according to claim 1, wherein the inner tube is ^-6 . 3. JIS B0651 and JIS B060
The surface roughness of the inner surface measured by the method according to 1 is 5
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 number ratio (O / C) of the inner surface measured by X-ray photoelectron spectroscopy is 0.04 to 0.4. Inner tube for. 5. An index I (D) / I (G), which represents a chemical bond state on the inner surface, measured by Raman spectroscopy [wherein I (D) is a peak value indicating a C—C bond in a diamond structure]. Represents
I (G) represents a peak value showing a C—C bond of a graphite structure] is 0.8 to 1.4, and the inner tube for CVD according to any one of claims 1 to 4.