JP2002308609A - Si DISPERSED VITREOUS CARBON MATERIAL - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an Si dispersed vitreous carbon material provided with a composite structure, in which Si is uniformly distributed as a continuous phase in the structure and having excellent chemical stability such as oxidation resistance or plasma resistance. SOLUTION: In the Si dispersed vitreous carbon material, Si is uniformly dispersed and combined in the structure of the vitreous carbon in atomic level and the bound energy of 2p orbit of Si atom, which is determined from the peak value of a photoelectron spectrum by an X-ray photoelectron spectroscopy(XPS), is 101-103 eV. The Si dispersed vitreous carbon material is provided with structural performance that a crystalline structure except graphite structure does not exist practically in the structure, the diffraction line attributed to metal Si or an Si compound is not detected in an X-ray diffraction method and granular structure is not discriminated by the observation by a transmission electron microscope(TEM).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glassy carbon structure having a homogeneous and dense composite structure structure in which Si is uniformly dispersed and compounded at the atomic level, and has chemical stability such as oxidation resistance and plasma resistance. The present invention relates to a Si-dispersed glassy carbon material having excellent properties.

[0002]

2. Description of the Related Art A vitreous carbon material is a vitreous material having a macroscopically non-porous three-dimensional network structure obtained by heating a thermosetting resin molded body in a non-oxidizing atmosphere and calcining and carbonizing. A hard carbon material that has superior gas impermeability, abrasion resistance, corrosion resistance, lubricity, surface smoothness and robustness compared to general carbon materials. It is useful as a member. In recent years, attention has been paid to non-contaminating material properties that do not allow fine carbon particles to be separated as particles from the tissue, and are suitable for semiconductor fields that dislike contamination such as electrodes for silicon wafer plasma etching and members for ion implantation equipment. It is used for

[0003] However, the glassy carbon material has a material defect inherent to the carbon material, which rapidly oxidizes in a high-temperature oxidizing atmosphere and deteriorates its physical properties, like a general carbon material. P, B, Si to improve the oxidation resistance of the carbon material
A method of adding an element such as P is known. However, when it is used as a member for manufacturing a semiconductor, addition of P, B, or the like is not preferable because it deteriorates the physical properties of the semiconductor.

[0004] Attempts have been made to improve the physical properties by combining a ceramic component such as Si in a glassy carbon structure. However, in a method of mixing ceramic fine particles with a thermosetting resin as a raw material by a dry or wet method and firing and carbonizing a molded body obtained by curing the same, the ceramic fine particles cannot be uniformly dispersed in a carbon structure, and Due to the presence of grain boundaries between the ceramic fine particles and the carbon structure, there are difficulties such as material destruction and severe separation of the ceramic fine particles under severe use conditions.

To eliminate these difficulties, there has been proposed a technique for improving oxidation resistance by using a raw material obtained by mixing a ceramic precursor with a thermosetting resin. For example, Japanese Patent Application Laid-Open No. 61-6111 discloses a liquid silicon compound, a liquid organic compound having a functional group, which can be carbonized by heating, and Si, O in which a polymerization or crosslinking catalyst is dissolved.
A method for producing an oxidation-resistant carbon material by carbonizing a precursor material containing C and C is disclosed. In this method, a silicic acid polymer obtained by dealkalization of water glass as a liquid silicon compound, an ester of a silicic acid with an organic compound containing a hydroxyl group, a Si ester such as ethyl silicate, a reaction product of silicon tetrachloride and ethanol, etc. It is essential that a catalyst be used in combination with sulfuric acid, hydrochloric acid, organic peroxides, organic sulfonic acids and the like.

However, in this method, in the process of forming a precursor material containing Si, O and C, the silicon compounds bond with each other to form fine aggregates, which are directly mixed with the Si-containing granular material in the carbonized structure. This tends to result in non-uniform texture that is dispersed. Further, even when a polymer ester in which a plurality of Si atoms are linked like a siloxane bond is used as a silicon source, a heterogeneous structure is similarly generated due to agglomeration. However, it is difficult to obtain a continuous phase carbonaceous structure in which Si is not dispersed in a particle state. In addition, if the combined catalyst is a strong acid such as sulfuric acid or hydrochloric acid, the gelation reaction will proceed rapidly and the tissue uniformity will be impaired.If a catalyst such as sodium ethylate or organic sulfonic acid is used, the inorganic components will remain. They become impurities and cause a reduction in purity.

JP-A-2-192411 discloses a monomer or an initial polycondensation of a thermosetting resin which produces a glassy hard carbon having high hardness and impermeability after firing and has a high carbon residue yield. Disclosed is a method for producing a carbon-based product, comprising mixing a product and an organosilicon resin, shaping the mixture into a desired shape, forming a heat-cured body, and then firing the mixture in an inert gas atmosphere. However, in this method, since an organosilicon resin is used as a silicon compound serving as a Si source, it is difficult to disperse Si at the atomic level in a glassy carbon structure to form a composite.

JP-A-5-43319 discloses a glassy state in which a thermosetting resin and an organometallic compound are uniformly mixed in a liquid state and heated (fired) to obtain an ultrafine ceramic which is highly dispersed. A carbon composite is disclosed.
In the present invention, as the organometallic compound serving as a silicon source, S
Polycarbosilane and polysilane to provide iC, Si
Ti-containing polycarbosilane that provides -Ti-CO, S
i _x N _y, polysilazanes to give Si-N-C or Si ₃ N ₄ -SiC is employed. However, when a polymer such as polycarbosilane or polysilane having a plurality of silane bonds is mixed with a thermosetting resin to form a raw material system, the ceramic source is dispersed as a polymer, so that fine metal carbide particles are formed after heat treatment. Inevitably, the formation of a grain boundary is unavoidable, and there is a problem that the texture becomes uneven. Therefore, the difficulty that the particles leave is not solved.

Therefore, the applicant of the present invention has previously described -O-Si-O-
Is obtained by firing and carbonizing the thermosetting resin molded product crosslinked in step 1.
A Si-containing glassy carbon material having a texture distributed as a uniform continuous phase in the range of 1 to 15% by weight, and a thermosetting resin and a Si alkoxide having a single Si atom in one molecule as its production technology. The hydrolyzate is stirred and mixed in an organic solvent, and the gelled product obtained by the crosslinking reaction is cured and molded.
A method of performing a carbonization treatment at the above temperature (Japanese Unexamined Patent Publication No. 8-325059)
No.).

Further, the present applicant has proceeded with research and development based on the above-mentioned technology, and has developed a thermosetting resin liquid containing an aminosilane compound containing a single Si atom in one molecule instead of a gelled product of a hydrolyzate of Si alkoxide. After the mixture is molded and cured, the cured molded body is subjected to a calcination treatment at a temperature of 800 ° C. or more in a non-oxidizing atmosphere to obtain a Si-containing glassy carbon material. A manufacturing method (Japanese Patent Application Laid-Open No. 9-59065), an improved invention of mixing and diluting an aminosilane compound with an organic solvent having a high carbonization residual ratio, dropping the diluted solution into a thermosetting resin liquid, and stirring and mixing. No. 9-110528). However, since the amino group has a high reactivity with the thermosetting resin, it has a disadvantage that local structural defects and the like are likely to occur due to a rapid reaction.
An invention using an epoxysilane compound containing a single Si atom in the molecule (JP-A-9-227231) was proposed.

[0011]

However, for use as an industrial member under more severe conditions, it is necessary to further improve the material properties. For example, when used as a member of a plasma etching apparatus or a plasma CVD apparatus for a silicon wafer for a semiconductor manufacturing apparatus, a reactive gas plasma obtained by mixing Ar, O _2, etc. with CF ₄ , CHF ₃ , SiH ₄ or the like. Therefore, it is necessary to provide a material having high plasma resistance, oxidation resistance, etc., and excellent chemical stability.

Furthermore, with the recent high integration of LSIs, the required plasma processing accuracy has been enhanced, and the plasma density has been increased in order to increase the production efficiency. Therefore, material properties that can be used for a long time are required.

The present inventor has conducted intensive studies on the Si-dispersed glassy carbon material in which Si atoms are uniformly dispersed and combined to further improve plasma resistance and oxidation resistance. It was confirmed that the electron-bonding state in the glassy carbon structure was closely related to maintaining high properties such as plasma resistance and oxidation resistance.

The present invention has been developed on the basis of the above findings, and an object of the present invention is to provide a Si-dispersed glassy carbon material having excellent chemical stability such as plasma resistance and oxidation resistance. is there.

[0015]

In order to achieve the above object, a Si-dispersed glassy carbon material according to the present invention has a structure in which Si is uniformly dispersed and compounded at the atomic level in the structure of glassy carbon, and X-ray photoelectron spectroscopy. It is characterized in that the binding energy of the 2p orbit of the Si atom obtained from the peak value of the photoelectron spectrum by the XPS method is in the range of 101 to 103 eV.

[0016] The microstructure of the glassy carbon in which Si is dispersed has substantially no crystal structure other than the graphite structure, and diffraction lines belonging to metallic Si and Si compounds are detected by X-ray diffraction. Not a transmission electron microscope (TE
It is characterized in that the granular structure has a texture that cannot be identified by the observation in M).

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The Si-dispersed glassy carbon material of the present invention has a structure in which Si is distributed as a uniform continuous phase at the atomic level in the structure of the glassy carbon. Is 0.5 to glassy carbon
It is preferable to adjust the content to a range of １５15 wt%. If the amount of Si is less than 0.5% by weight, sufficient chemical stability cannot be imparted. On the other hand, if the amount exceeds 15% by weight, Si can be stably dispersed in the glassy carbon structure at the atomic level. Because it becomes difficult.

In order to improve the plasma resistance and oxidation resistance of the Si-dispersed glassy carbon material having a textured property in which Si atoms are uniformly dispersed and compounded, it is necessary to use Si
The atoms need to have a binding energy of 2p orbitals of Si atoms determined from a peak value of a photoelectron spectrum by X-ray photoelectron spectroscopy (XPS) in a range of 101 to 103 eV.

The photoelectron spectrum measured by X-ray photoelectron spectroscopy (XPS) differs depending on the bonding state of Si, and the peak value of the photoelectron spectrum changes. For example, when Si is in the metal state, the binding energy of the 2p orbit of the Si atom determined from the peak value of the photoelectron spectrum by X-ray photoelectron spectroscopy (XPS) is 99 eV, and when Si is in the carbonized state, ie, SiC The binding energy of the 2p orbital of the Si atom in the inside is 100.3 eV, and when Si is in the oxidation state, that is, the binding energy of the 2p orbital of the Si atom in SiO ₂ is 103.4 eV. In general, as metals are oxidized, the binding energy tends to increase.

The Si-dispersed glassy carbon material of the present invention comprises:
By setting the binding energy of the 2p orbit of Si atoms determined from the peak value of the photoelectron spectrum by X-ray photoelectron spectroscopy (XPS) to a range of 101 to 103 eV,
It is intended to improve plasma resistance and oxidation resistance.

The binding energy of the 2p orbit of the Si atom is 1
When it is in the range of from 01 to 103 eV, plasma resistance and oxidation resistance are improved, for example, the resistance to active radical species in gas plasma is improved, and the detailed reason why the chemical stability is increased is unknown. It is presumed to be due to the following mechanism.

That is, the bonding state of Si atoms in the Si-dispersed glassy carbon material of the present invention is, as described above, Si atoms in a metal state, Si atoms in SiC, or SiO _2.
It is also different from the bonding state of Si atoms in the inside. Therefore, Si atoms in such a bonded state do not substantially exist in the form of metallic Si particles, SiC or SiO _{2 in} the structure of glassy carbon, and Si atoms at the atomic level are present.
Is in a state of being uniformly dispersed and composited in the glassy carbon structure. As a result, Si is not desorbed as particles when the glassy carbon material is consumed, and the uniformly dispersed Si atoms protect the reactive active sites that are likely to be the starting points when the glassy carbon is consumed, thereby improving chemical stability. It is thought to function to improve

As described above, the structure of the Si-dispersed glassy carbon material of the present invention is such that the structure of Si
A structural state in which the components are not dispersed in a fine particle state and a continuous solid solution phase in which no Si and C grain boundaries do not exist in the structure, that is, a macroscopically substantial difference from the structural structure of glassy carbon alone However, microscopically, it shows a composite form in which a part of the glassy carbon structure is substitutionally bonded to Si. Thus, the organizational structure, specifically, substantially absent crystal structure other than the graphite structure tissue of Si dispersed glassy carbon, a metal by a pattern analysis by X-ray diffractometry Si and SiC or SiO ₂ Such as Si
No diffraction line attributed to the compound is detected, and a unique texture is formed in which the granular structure cannot be identified by observation with a transmission electron microscope (TEM), thereby improving plasma resistance and oxidation resistance.

The Si-dispersed glassy carbon material of the present invention
An organic silane compound is mixed with a thermosetting resin to prepare a raw resin liquid, the raw resin liquid is molded into a desired shape, and then heat-cured. Can be manufactured. Thermosetting resin is a carbon source that is converted into glassy carbon by firing carbonization treatment, and various resins usually used for glassy carbon production, for example, phenolic resin, furan resin, polyimide resin, epoxy resin A system resin, a polycarbodiimide resin, a pyrene-phenanthrene resin, or the like is used alone or as a mixture.

The organic silane compound is a raw material component for dispersing and compounding Si in a glassy carbon structure, and the organic silane compound is mixed and uniformly dispersed in a thermosetting resin liquid to prepare a raw resin liquid. Is done. As the organic silane compound, an organic silane compound having at least one Si atom in one molecule and having one or more O atoms bonded to the Si atom, for example, represented by the following general formula is used.
However, in the following general formula, R _{1 to} R ₄ are C, H, O,
At least one of R _{1 to} R ₄ containing N or Si is an organic functional group having O at the terminal bonded to the Si atom. In this case, it is desirable that the number of Si atoms in one molecule does not exceed 3. The number of Si atoms in one molecule is 3
When Si exceeds 3, Si atoms are likely to be aggregated, and the Si component is aggregated and dispersed at a nano-level or a micro-level. As a result, it is difficult to disperse Si at an atomic level.

[0026]

As described above, S in the organic silane compound
By controlling the i content, the O content, and the like, and adjusting the quantitative ratio of the organic silane compound to the thermosetting resin to prepare a raw resin solution, the photoelectron spectrum by X-ray photoelectron spectroscopy (XPS) can be obtained. The Si-dispersed glassy carbon material of the present invention, in which the binding energy of the 2p orbit of Si atoms determined from the peak value is in the range of 101 to 103 eV, can be produced.

[0028]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples.

Example 1 As an organic silane compound, 3-aminopropyltriethoxysilane (TSL8345 manufactured by Toshiba Silicone Co., Ltd.) was used.
The mixture was stirred and mixed for 1 hour while being dropped onto a phenol resin (PR-940, manufactured by Sumitomo Durez Corp.) so that the Si content was 2 wt%. Thereafter, the mixture was allowed to stand for 45 hours in a gentle fluidized state with gentle stirring at room temperature to enhance the homogeneity. The raw material resin liquid thus prepared was poured into a molding die, deaerated in a vacuum device, and then heated to a temperature of 70 to 180 ° C. to be cured. The obtained cured molded body is placed in a heating furnace maintained in a nitrogen atmosphere, heated to a temperature of 1000 ° C., calcined and carbonized, and further heated to a temperature of 2000 ° C. in a mixed gas atmosphere of chlorine / helium to achieve high purity. Processing was performed. Thus S
An i-dispersed glassy carbon material was produced.

Examples 2-3 Using 3-glycidoxypropylmethyldimethoxysilane as an organic silane compound, the mixture was dropped and mixed with a phenol resin so that the Si content was 2 wt% and 7 wt%, and the raw material resin liquid was mixed. Except for the preparation, a Si-dispersed glassy carbon material was produced in the same manner as in Example 1.

Comparative Example 1 An Si-dispersed glassy carbon material was produced in the same manner as in Example 1, except that a raw material resin liquid was used only with a phenol resin without mixing an organic silane compound.

Comparative Example 2 Tetraethoxysilane was dissolved in anhydrous ethanol so as to have a concentration of 50 Vol%, stirred for 30 minutes with a stirrer, and then subjected to a dispersion treatment for 2 hours by an ultrasonic vibrator. To this solution, 0.03 mol equivalent of anhydrous acetic acid and 1 mol equivalent of water were added dropwise to tetraethoxysilane, and the mixture was stirred and mixed for 1 hour with a stirrer to hydrolyze tetraethoxysilane. Then, while stirring the hydrolyzed tetraethoxysilane, the phenol resin liquid previously dissolved in anhydrous ethanol, stirred with a stirrer for 30 minutes, and then subjected to a dispersion treatment for 2 hours with an ultrasonic vibrator was gradually added, Subsequently, the mixture was stirred with a stirrer for 1 hour and mixed until uniform. Example 1 except that this raw material resin liquid was used
A Si-dispersed glassy carbon material was produced in the same manner as in the above.

Comparative Example 3 Polysiloxane was used as an organosilane compound,
A Si-dispersed glassy carbon material was produced in the same manner as in Example 1, except that a raw material resin liquid was prepared by dropping and mixing the phenol resin so that the content became 2 wt%.

Comparative Example 4 SiO ₂ powder (manufactured by Nilaco Co., SI-507250; particle size 150 μm,
(Purity: 99.99%) was mixed with a phenol resin so that the Si content was 5 wt%, and a Si-dispersed glassy carbon material was produced in the same manner as in Example 1.

Comparative Example 5 SiO ₂ powder (manufactured by Nilaco Co., SI-507203; particle size 0.5 μm,
A Si-dispersed glassy carbon material was produced in the same manner as in Comparative Example 4, except that the purity was 98.7%.

The Si-dispersed glassy carbon material thus manufactured was measured and evaluated for the content of Si atoms, binding energy, texture, oxidation resistance, plasma resistance, and the like by the following methods. Are shown in Table 1.

(1) Si content: The sample was ashed to a constant weight and measured according to JIS G1212.

(2) Binding energy; X-ray irradiation using an X-ray photoelectron spectrometer (JPS-9000MC) manufactured by JEOL; MgK
α (application condition 10 kV, 20 mA), measurement range: 98 to 108 e
V, the number of integrations: 20, the photoelectron spectrum obtained under the measurement conditions of 20 was subjected to waveform separation processing, and 2
The binding energy of the p-orbit was measured. Note that 101 to 1
When there was no peak value in the range of 03 eV, the maximum intensity peak value was shown.

(3) X-ray measurement: The presence or absence of diffraction lines belonging to metallic Si and the Si compound was observed by a method based on the Gakushin method to confirm the presence of crystalline Si and the Si compound.

(4) TEM observation: The sample was cut, and the fractured surface was observed at 10 places at a magnification of 3,000,000 times at random to confirm the presence or absence of a granular structure.

(5) Oxidation resistance: The weight loss rate was measured using a muffle furnace at a temperature of 950 ° C. for 1 hour in a still air atmosphere. (Sample size: 15 x 15 x 2 mm)

(6) Plasma resistance; a sample was set in a plasma etching apparatus (PR41, manufactured by Yamato Scientific Co., Ltd.), and reaction gas: CF ₄ , O ₂ , gas pressure in a reaction chamber; 1.3
Etching was performed under the conditions of × 10 ² Pa and a power supply frequency of 13.5 MHz, and the thickness reduction per unit time was calculated. (Sample size: 15 x 15 x 2 mm)

[0043]

[Table 1]

From Table 1, it can be seen that the binding energy of the Si atom is 1
The Si-dispersed glassy carbon materials of Examples 1 to 3 in the range of 01 to 103 eV have a small weight loss rate due to oxidative depletion and a small wall loss rate due to plasma treatment, and are excellent in oxidation resistance and plasma resistance. Is recognized. On the other hand, in Comparative Example 1 containing no Si atom, both the weight reduction rate and the wall thickness reduction amount were remarkably large, indicating that the oxidation resistance and the plasma resistance were poor. Comparative Examples 2 to 5 in which the binding energy of Si atoms is not in the range of 101 to 103 eV.
All of the Si-dispersed glassy carbon materials of Examples 1 to
As compared with the Si-dispersed glassy carbon material of No. 3, the weight reduction rate due to oxidation consumption and the wall thickness reduction amount due to the plasma treatment are larger.

Further, as for the structural properties of the Si-dispersed glassy carbon materials of Examples 1 to 3, the crystal structure and granular structure of the Si compound were not observed, and atomic level Si was uniformly dispersed and compounded in the glassy carbon structure. It is in the state. Therefore, there is no grain boundary, Si atoms which are not dispersed as particles at the time of consumption and are uniformly dispersed and compounded protect reaction active sites which are likely to be a starting point at the time of consumption of glassy carbon, and have oxidation resistance. Also, the plasma resistance is high, and the chemical stability is improved. On the other hand, in the Si-dispersed glassy carbon materials of Comparative Examples 3 to 5, S
It can be seen that the i-compound has a crystal structure and a granular structure, and particles are easily generated at the time of consumption.

[0046]

As described above, according to the Si-dispersed glassy carbon material of the present invention, S
i are uniformly dispersed and compounded at the atomic level, and the binding energy of the 2p orbit of the Si atom determined from the peak value of the photoelectron spectrum by X-ray photoelectron spectroscopy (XPS) is 101 to 10
3 eV, and the microstructure of the Si-dispersed vitreous carbon is substantially free from the crystal structure other than the graphite structure.
Diffraction lines belonging to the compound are not detected, and the structure is such that the granular structure cannot be identified by observation with a transmission electron microscope (TEM). Therefore, the chemical stability such as oxidation resistance and plasma resistance is low. In addition, the generation of particles is effectively suppressed even at the time of consumption. Therefore, a silicon wafer plasma etching apparatus or plasma CVD
It is extremely useful as various industrial members used under severe conditions, including heat-resistant members for semiconductor manufacturing equipment such as equipment.

Claims (2)

[Claims] 1. Si is uniformly dispersed and compounded at the atomic level in the structure of glassy carbon, and is analyzed by X-ray photoelectron spectroscopy (XP
Si obtained from the peak value of the photoelectron spectrum by S)
The binding energy of the 2p orbit of the atom is 101-103 eV
A Si-dispersed glassy carbon material characterized by the following range: 2. The structure of the Si-containing glassy carbon has substantially no crystal structure other than the graphite structure, and diffraction lines belonging to metallic Si and the Si compound are not detected by the X-ray diffraction method. The Si-dispersed glassy carbon material according to claim 1, wherein the Si-dispersed glassy carbon material has a texture characteristic in which a granular structure cannot be identified by observation with an electron microscope (TEM).