JP3000431B2 - Method for testing abatement agents and their raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abatement agent and a method for inspecting a raw material thereof, and more particularly, to a volatile inorganic hydride, a volatile inorganic halide, or an organic compound used as a raw material gas in a semiconductor manufacturing process or the like. The present invention relates to a scavenger containing crystalline cupric hydroxide as a main component for removing a harmful component such as a metal compound, and a method of inspecting a raw material when producing the scavenger.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a volatile inorganic hydride such as silane, arsine, phosphine, a volatile inorganic halide or an organometallic compound is supplied as a raw material gas to various semiconductor substrate processing apparatuses. Therefore, the exhaust gas from various semiconductor substrate processing apparatuses includes the unreacted raw material gas. Since these raw material gases are harmful, it is necessary to remove these harmful components in the exhaust gas to make them harmless before releasing the exhaust gas to the atmosphere.

As a method of detoxifying the exhaust gas containing the harmful components, a method of distributing the exhaust gas to a detoxifying cylinder filled with a solid detoxifying agent containing a metal oxide such as copper oxide as a main component has been widely used. ing. However, among the volatile inorganic hydrides, the solid abatement agent containing a metal oxide as a main component has a disadvantage that the treatment amount of silane is small.

[0004] In order to solve the above-mentioned drawbacks of metal oxides, the present applicant has previously proposed an abatement agent containing cupric hydroxide as a reaction main component (see JP-A-6-319945). ). And, as cupric hydroxide, a crystalline thing has an excellent abatement ability to silane, and further, to volatile inorganic hydrides other than silane, volatile inorganic halides, organometallic compounds, etc. Also disclosed that the abatement ability was widely exhibited.

[0005]

However, when various crystalline cupric hydroxides are prepared, formed into pellets, and detoxification of harmful components is performed using these, the detoxification performance is reduced. Variation sometimes occurred. In view of the above, the present inventors have investigated the cause of the dispersion in the performance of the abatement agent containing crystalline cupric hydroxide as a main component of the reaction, and conducted intensive research to obtain an abatement agent with stable performance. Stacked. As a result, it has been found that even if the cupric hydroxide is crystalline, which is chemically expressed as Cu (OH) ₂ , the performance differs depending on the crystal grain size.

[0006]

Means for Solving the Problems The abatement agent of the present invention and the method for inspecting the raw material thereof are made based on the above-mentioned findings. It is an abatement agent containing cupric copper as a main component, and is obtained from X-ray diffraction of cupric hydroxide using a diffraction line of a lattice plane (0, 2, 1) of cupric hydroxide. ), "D =
(0.9 · λ) / (β · cos θ) ”(where D is the crystal grain size [angstrom], λ is the X-ray wavelength [angstrom], β is the half-width of the diffraction line [radian], θ is (Diffraction angle)) is characterized mainly by using cupric hydroxide having a crystal grain size D of 40 Å or more.

[0007] Further, the method for inspecting raw materials for abatement agents of the present invention comprises:
When a raw material containing crystalline cupric hydroxide as a main component is formed into pellets to produce an abatement agent, a lattice plane (0, 2, 1) of cupric hydroxide is determined from X-ray diffraction of the raw material. The crystal grain size D obtained by the above-mentioned Scherrer's formula using the diffraction line of 4) is 4
It is characterized in that cupric hydroxide of 0 Å or more is accepted.

[0008] Further, when the harmful substance contains silane, the crystal grain size D obtained by the above Scherrer's formula is 90%.
It is characterized in that cupric hydroxide having a thickness of Å or more is accepted and used as a main component of the abatement agent.

The cupric hydroxide used as the main reaction component of the abatement agent is generally obtained by neutralizing and precipitating an aqueous solution of various copper salts (II) with various bases, followed by filtration and drying. Can be Thus, various copper hydroxides were prepared by changing the conditions in the neutralization method, and these were also subjected to powder X-ray diffraction, including commercially available cupric hydroxide. Then, the crystal grain size was determined by the above-mentioned Scherrer's formula using the diffraction line of the lattice plane (0, 2, 1) of cupric hydroxide. , With a crystal grain size of 20
Up to about 0 angstroms were present. In addition,
Those having a large crystal grain size exceeding 200 angstroms were difficult to prepare by a usual method.

Next, as a result of conducting an abatement experiment using cupric hydroxide having various crystal grain sizes, the relationship between the crystal grain size obtained by the above-mentioned Scherrer's formula and the abatement performance was extremely strong. It was found that the larger the crystal grain size, the better the abatement performance. That is, in the X-ray diffraction chart of FIG. 1, the crystalline one shown by the line A exhibits more excellent abatement performance than the non-crystalline one shown by the line B.

As a result of examining the harmful performance by variously selecting harmful components to be a harmful gas, it was found that, with respect to harmful components other than silane, if the crystal grain size determined by the above-mentioned Scherrer's formula is less than 40 Å, it is sufficient. Performance was not obtained, and those having a crystal grain size of 40 Å or more were found to be suitable as a scavenger. Furthermore, when the relationship between the crystal grain size and the abatement performance was examined for silane, for silane, if the crystal grain size determined by the Scherrer's formula was 40 Å or more,
Although it is possible to improve the detoxification ability to some extent as compared with those below, it has been found that sufficient detoxification performance can be obtained by using cupric hydroxide of 90 Å or more.

In addition, cupric hydroxide having a crystal grain size of 90 Å or more can more efficiently remove not only silane but also other harmful components such as other arsine and phosphine. Preferably, cupric hydroxide having a crystal grain size of 90 Å or more, whether or not containing silane, is used as the main component of the scavenger.

Although it is necessary to form such an abatement agent using cupric hydroxide as a raw material in consideration of gas permeability, the cupric hydroxide powder is used as is in a tableting machine. Or the like, or may be formed into a pellet after adding another substance as a carrier or a stabilizer to the cupric hydroxide powder. Furthermore, when preparing an aqueous solution of copper salt by neutralizing an aqueous solution of copper salt (II), a powder obtained by adding a substance acting as a carrier or a stabilizer to the aqueous solution and co-precipitating it is used as a raw material. You can also.

Further, when it was confirmed whether or not the crystal particle size of cupric hydroxide changes when being formed into pellets with a tableting machine, in this forming step, the crystal particle size of cupric hydroxide is as follows:
It was confirmed that it did not change. Therefore, if the raw material before molding is subjected to X-ray diffraction and the cupric hydroxide having a crystal grain size of less than 40 angstroms is selected as unqualified, the cupric hydroxide is used as a scavenger before the forming step. It is possible to judge whether or not it is appropriate, and it is possible to eliminate the waste of molding an unsuitable one, and to provide an abatement agent having a predetermined performance.

The harmful components which can be subjected to the abatement treatment with the abatement agent of the present invention are, in particular, volatile inorganic hydrides, volatile inorganic halides, and organometallic compounds used in semiconductor manufacturing plants and the like. Examples of the volatile inorganic hydride include diborane, silane, disilane, germane, ammonia, phosphine, arsine, hydrogen sulfide, and hydrogen selenide. Examples of the volatile inorganic hydride include boron trifluoride. , Boron trichloride, silicon tetrafluoride,
Examples include various gases including halogen gas such as dichlorosilane, trichlorosilane, silicon tetrachloride, trichloroarsine, tungsten hexafluoride, fluorine, chlorine, hydrogen fluoride, hydrogen chloride, and hydrogen bromide.

Further, as the organometallic compound, dimethyl zinc, diethyl zinc,
Trimethylaluminum, triethylaluminum, trimethylgallium, triethylgallium, trimethylindium, triethylindium, tetramethyltin, tetraethyltin, tertiarybutylphosphine, trimethylarsine, triethylarsine, tertiarybutylarsine, etc. as those containing an alkoxide group; Dimethoxyzinc, tributoxygallium, trimethoxyboron, triethoxyboron, tetramethoxysilane, tetraethoxysilane, tetramethoxygermane, tetraethoxygermane, tetratertiarybutoxytin, trimethoxyphosphine, triethoxyphosphine, trimethoxyarsine, trimethoxyzinc Ethoxyarsine, tetraethoxyselenium, tetramethoxytitanium, tetraethoxytitanium, tetraiso Ropokishichitan, tetraisopropoxy zirconium, tetra-tertiary-butoxy zirconium, pentamethoxy tantalum, pentaethoxytantalum etc. can be mentioned, respectively.

[0017]

EXAMPLES Examples and comparative examples of the present invention will be described below. Examples and Comparative Examples Various cupric hydroxide samples were subjected to X-ray (CuKα) diffraction, and the half-value width of the diffraction line (see FIG. 1) on the (0, 2, 1) plane was measured (corrected with standard Si). ), The crystal grain size was calculated by the above Scherrer's formula, and as shown in Table 1, the crystal grain size was 30
Six types of cupric hydroxide raw materials in the range of -170 angstroms were used.

These various cupric hydroxide raw material powders were formed into pellets having a thickness of 3 mm and a diameter of 3 mm using a tableting machine. After the molding, the pellets were pulverized and the crystal grain size was calculated in the same manner. As a result, none of the samples was the same as the crystal grain size before the molding.

Each cupric hydroxide pellet having a different crystal grain size is packed into a column having an inner diameter of 43 mm to a height of 100 mm, and a test gas containing a harmful component is flowed through the column to supply the gas until breakthrough of the abatement agent. The processing amount [liter] per 1 kg of the abatement agent was calculated from the amount of the harmful component gas and the amount of the abatement agent.

The test gases containing harmful components include the following G1
Six types of G6 were used. G1: Nitrogen containing 0.5% silane G2: Hydrogen containing 0.5% silane G3: Nitrogen containing 0.5% arsine G4: Hydrogen containing 0.5% arsine G5: 0.5% G6: Hydrogen containing 0.5% phosphine The velocities of each test gas were 0.5 cm / sec, the breakthrough concentration of silane was 5 ppm, and the breakthrough concentration of arsine was 0.1%.
The phosphine breakthrough concentration was set to 0.3 ppm. Table 1 shows the results.

[0021]

[Table 1]

[0022]

As described above, according to the present invention,
It is possible to reliably obtain an abatement agent having extremely high abatement ability.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction chart of two types of cupric hydroxides having different crystallinities.

[Explanation of symbols]

A: crystalline cupric hydroxide, B: amorphous cupric hydroxide

────────────────────────────────────────────────── (5) References JP-A-6-319945 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53/46 B01D 53/68 B01J 20 / 02

Claims (4)

(57) [Claims] 1. An abatement agent containing crystalline cupric hydroxide as a main component, and the X-ray diffraction of cupric hydroxide indicates that the lattice plane (0, 2, Scherrer's equation using the diffraction line of 1), D = (0.9 · λ) / (β · cos θ) (where D is the crystal grain size [angstrom], λ is the wavelength of X-ray [angstrom], β is the half value width of the diffraction line [radian], and θ is the diffraction angle.) A scavenger characterized by mainly using cupric hydroxide having a crystal grain size D of 40 Å or more. 2. The harm-removing object of the harm-removing agent contains silane,
2. The harm-removing agent according to claim 1, wherein cupric hydroxide having a crystal grain size D determined by the Scherrer's formula of 90 Å or more is mainly used. 3. When a raw material containing crystalline cupric hydroxide as a main component is formed into pellets to produce an abatement agent, a lattice plane of cupric hydroxide is determined from X-ray diffraction of the raw material. 0,2,
Scherrer's equation using the diffraction line of 1), D = (0.9 · λ) / (β · cos θ) (where D is the crystal grain size [angstrom], λ is the wavelength of X-ray [angstrom], β is the half width of the diffraction line [radian], and θ is the diffraction angle.) The cupric hydroxide having a crystal grain size D of 40 Å or more is determined to be acceptable. Inspection methods. 4. The harm-removing object of the harm-removing agent contains silane,
4. The method of claim 3, wherein cupric hydroxide having a crystal grain size D determined by the Scherrer equation of 90 Å or more is accepted.