JPH06319945A - Removing agent and detecting agent of harmful component - Google Patents

Abstract

PURPOSE:To obtain an agent for removing a greater amount of a harmful component such as silane and an agent for detecting the generation etc., of a harmful component by using copper hydroxide as a main component in a reaction. CONSTITUTION:A removing agent and a detecting agent are obtained by using copper hydroxide, especially crystalline copper hydroxide, as a main component in a reaction. The removing agent can remove efficiently a harmful component in exhaust gas etc., such as a volatile inorganic hydrogen compound (e.g. silane), a volatile inorganic halogen compound (e.g. boron trifluoride), and an organometallic compound (e.g. dimethylzinc) to downsize the reaction tube or to extend the exchange cycle of the removing agent. The removing agent, having enough removing power even with a smaller specific surface, can reduce its manufacturing cost. Since the removing agent is discolored by the reaction with a harmful component, the behavior of the agent is detected by the color change, so that the agent can also be used as a detecting agent of a harmful component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a removing agent and a detecting agent for harmful components contained in exhaust gas, etc., and more particularly to volatile inorganic hydrides, volatile inorganic halides and organic compounds used in semiconductor manufacturing plants. The present invention relates to a remover and a detector for harmful components in exhaust gas containing harmful components such as metal compounds.

[0002]

2. Description of the Related Art Exhaust gas containing these harmful components is discharged from a semiconductor manufacturing process using harmful gas components such as volatile inorganic hydrides, volatile inorganic halides and organometallic compounds. These harmful components are toxic and flammable and dangerous and must be rendered harmless before the exhaust gas is released into the atmosphere.

Detoxification treatment of harmful components in exhaust gas in a semiconductor manufacturing plant has been shifted from a conventional wet or wet semi-wet method using a removing agent to a dry treatment technology in recent years. . For example, Japanese Examined Patent Publication No. 3-64166 and Japanese Examined Patent Publication No. 3-64167 disclose a remover mainly composed of copper oxide as a remover of a harmful gas containing arsenic. Is a remover mainly composed of copper oxide or a mixture of copper oxide and zinc oxide as a remover of a gaseous silicon compound,
Each is listed. Furthermore, Japanese Patent Publication 4-1988
No. 6 discloses a silane-based gas removing agent containing a metal oxide as a main component.

As a method for removing harmful gas components using the above-mentioned removing agent, generally, the harmful components are brought into contact with the removing agent through exhaust gas containing the harmful components in a filling cylinder filled with the removing agent. A method of removing harmful components is adopted. When treating exhaust gas containing harmful components by this method,
When the removing ability of the removing agent is lowered and the ability of the removing agent is exceeded as the removing process progresses, the harmful component in the exhaust gas passing through the removing agent-filled cylinder exceeds a predetermined concentration. Therefore, replace the scavenger before the scavenging ability of the scavenger decreases,
It has to be refilled, but it costs a lot of equipment and labor to mount an expensive analyzer in the latter stage of the packing cylinder in order to confirm the deterioration of the capacity of the remover, that is, the breakthrough of the remover in advance. . Therefore, various detection agents have been developed to detect the breakthrough of the remover easily and reliably.

As the detection agent, for example, a detection agent for detecting harmful gas containing arsine, phosphine, diborane, hydrogen selenide, germane, monosilane, disilane, dichlorosilane, etc., using basic copper carbonate as a discoloring component Agent (Japanese Patent Publication No. 4-79576), a detection agent containing a copper salt of an organic acid as a discoloring component (Japanese Patent Publication No. 4-79577),
A detection agent (Japanese Patent Publication No. 4-79578) that uses a mixture of a cupric salt and a palladium salt as a discoloring component has been proposed. On the other hand, in JP-A-4-97752,
Copper nitrate has been proposed as a detection agent that is inexpensive, is sensitive to discoloration, and has no discoloration.

Further, as a detecting agent for detecting a harmful gas containing an organic metal compound such as an alkyl compound of a metal, a detecting agent containing a mixture of a copper salt and a gold salt as a discoloring component (Japanese Patent Laid-Open No. HEI 2)
110369, Japanese Patent Laid-Open No. 2-110370)
Is proposed.

[0007]

However, the conventional scavenger containing the above-mentioned metal oxide such as copper oxide as a reactive main component has a small ability to remove silane. It was necessary to support the carrier on alumina or the like to increase the specific surface area, and it was troublesome to manufacture the removing agent itself. Therefore, the appearance of a removing agent having a larger removing ability has been desired.

Further, the above-mentioned removing agent containing copper and an oxide of a metal other than copper as a main component is used together with a detecting agent for detecting breakthrough of its removing ability in order to accurately grasp the replacement time. There is a need.

On the other hand, as for the detecting agent for detecting the breakthrough of the removing agent, the raw material is expensive such as palladium salt and gold salt, and the cost for manufacturing process such as dissolution, precipitation, filtration and drying of copper salt is high. Also takes. In addition, the detection agent that uses copper nitrate as the discoloring component has excellent performance as a detection agent, but if the reaction with the target gas proceeds excessively, it may generate nitric oxide, so use it as a removal agent. Is not preferable.

Therefore, the present inventors have a sufficient ability to remove silane-based harmful components, and have various types such as arsine-based and phosphine-based compounds, and various organometallic compounds used in semiconductor manufacturing processes. The first purpose is to develop a remover effective against harmful components of the plant, and at the same time, to develop a remover that has the ability to detect breakthrough of the removal ability by itself and does not require a detector. As a secondary purpose, he has conducted extensive research. As a result, copper hydroxide has about four times the ability to remove silane-based harmful gases compared to conventional copper oxide, and at the same time, other volatile inorganic hydrogen compounds such as arsine and phosphine, The volatile inorganic halide, further, it is possible to effectively remove the organometallic compound, and the color thereof is found to be able to detect breakthrough by vividly changing color from blue to black by the reaction, The present invention has been completed.

[0011]

That is, the removing agent or detecting agent of the present invention is characterized by containing copper hydroxide as a reaction main component, and in particular, the copper hydroxide is a crystalline water. It is characterized by being copper oxide.

The harmful components to which the present invention is applied include volatile inorganic hydrides, volatile inorganic halides, organometallic compounds and the like used in semiconductor manufacturing plants and the like. Examples of the volatile inorganic hydride include diborane, silane, disilane, germane, ammonia, phosphine, arsine, hydrogen sulfide, hydrogen selenide, and the like, and volatile inorganic halides include boron trifluoride. , Boron trichloride, silicon tetrafluoride, dichlorosilane, trichlorosilane, silicon tetrachloride, trichloroarsine, tungsten hexafluoride, fluorine, chlorine, hydrogen fluoride, hydrogen chloride, hydrogen bromide, etc. Can be mentioned.

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

Further, when the copper hydroxide as the main component is brought into contact with the above-mentioned gas to be removed and reacts with it, the color changes sharply from blue to black. Since the front advances, it is not necessary to use a detection agent, but it can be used as a detection agent for the gas to be removed, if necessary.

[0015]

[Operation] When the exhaust gas containing the harmful component is brought into contact with copper hydroxide, the harmful component in the exhaust gas reacts with the copper hydroxide to be removed. Particularly in the case of silane, the amount of silane removed per unit weight of the reaction main component copper hydroxide is much larger than that of the conventional remover copper oxide. There are various possible causes for this, but one is probably that copper hydroxide has a higher proportion of the removal component contributing to the reaction than copper oxide. For example, in the case of copper oxide, even if it is made into a fine powder and supported on a carrier to increase the specific surface area, the diameter of each copper oxide is about several microns at the minimum, and the reaction is several angstroms (diameter of the surface). (Thickness about 1/1000), only the surface of the substance contributes to the reaction, and the copper oxide inside remains unreacted, whereas in the case of copper hydroxide,
It is presumed that this is because the reaction proceeds to the inside of the substance.
In fact, in the case of copper hydroxide, a large amount of silane can be removed even if the specific surface area is small. Therefore, the removing agent of the present invention exerts sufficient removing ability even when it is carried on a carrier or when it is used alone in the form of tablets. These are findings obtained by the present inventors through various studies.

In the present invention, the main component, copper hydroxide, means mainly cupric hydroxide (Cu (OH) ₂ ), but it may also contain cuprous hydroxide. As the copper hydroxide, both crystalline and amorphous ones can be used, but since the crystalline one is more stable against temperature than the amorphous one, the concentration of harmful components is high. It can be used more stably when the reaction heat is high. Although the reaction in the present invention is an exothermic reaction, the calorific value is almost the same as that of the above-mentioned copper oxide which is a conventional removing agent.

Further, when the above-mentioned copper hydroxide comes into contact with the harmful component, the harmful component reacts sensitively with it even at a small concentration to remove it, and at the same time, changes color from blue to black.
The breakthrough can be detected. Therefore, the breakthrough as a remover can be confirmed by monitoring the discoloration state of the copper hydroxide. Specifically, if the filling agent provided with a transparent or transparent window is filled with the removing agent of the present invention, the transition of the breakthrough front from the upstream side can be observed by discoloration, so that the removing agent can be prepared with a margin. You can know when to replace.

Further, the detecting agent of the present invention can be used only as a detecting agent for detecting the breakthrough of other removing agents.

In the method and remover of the present invention,
Copper hydroxide may be used alone as a removing agent, or may be used as a mixture with other components. Further, it is possible to further improve the performance by subjecting to a carrier of silicate such as alumina, silica or diatomaceous earth to increase the specific surface area by subjecting to the same fine-graining treatment as in the prior art.

In addition, the conventional remover containing copper oxide as a main component may contain a trace amount of copper hydroxide as a residue in the step of producing copper oxide. This copper hydroxide remains as an impurity to the last, and is essentially different from that used as the main component of the removing agent or the detecting agent as in the present invention.

[0021]

EXAMPLES Reference examples and examples of the present invention will be described below. Example 1 First, the following are prepared as a remover and a test gas,
A column having an inner diameter of 43 mm and a height of 685 mm was filled with these removers at a height of 300 mm, and a test gas containing silane as a harmful component was passed through the column.
The throughput of various removers was measured. The treatment capacity of each scavenger was measured by measuring the silane concentration at the column outlet with a detector (AD-10 analyzer manufactured by Nippon Oxygen), and using the scavenger when the silane concentration at the outlet reached 5 ppm. As a limit, the amount of silane introduced until the usage limit is reached depends on the removal agent 1k
It was performed by calculating the amount of silane treatment per g.
The specific surface area of each remover was measured by the well-known BET method.

Remover A: Commercially available cupric hydroxide powder (manufactured by Kanto Kagaku). B: A molded product after drying a precipitate (copper hydroxide) obtained by mixing 1 mol / l of a copper sulfate solution and 1 mol / l of sodium hydroxide. C: Molded product of commercially available cupric oxide powder (manufactured by Kanto Kagaku). D: Cupric oxide molded product obtained by firing basic copper carbonate. E: Cupric oxide supported on aluminum oxide by firing a precipitate obtained by mixing three kinds of aqueous solutions of an aqueous solution of copper nitrate, an aqueous solution of aluminum nitrate and an aqueous solution of sodium carbonate. The removers A and B are both crystalline. Each molded product is an extrusion molded product, and its size is 1.5 mm in diameter and 5 mm in length.

Test gas G1: Silane concentration 1% based on nitrogen, flow rate 1.0 l / min. G2: Silane concentration 10% based on nitrogen, flow rate 0.1 liter / min.

Table 1 shows the measurement results of the treating ability of each removing agent.

[Table 1]

As is clear from Table 1, the removal agents A and B made of copper hydroxide have a very high processing capacity as compared with the conventional removal agents C, D and E. Further, in the conventional product, it is necessary to increase the specific surface area in order to obtain the necessary and sufficient processing capacity, and to reduce the particle size as much as possible, and
Although it is necessary to increase the specific surface area by loading it on a carrier, the removal agent consisting of copper hydroxide has a specific surface area of half that of the removal agent E, which has the largest specific surface area among conventional products. Since it has a processing capacity more than double, sufficient processing capacity can be obtained without special special surface area expansion processing. Therefore, it is possible to miniaturize the reaction tube filled with the removing agent and extend the exchanging cycle of the removing agent.

Example 2 The same cupric hydroxide powder as that used for the remover A of Example 1 was molded into a size of 1 mmφ × 3 mm, and the inner diameter was 40 mm and the height was 5 mm.
About 200 g was packed in a 00 mm transparent column (packing length: 150 mm). After purging the column with nitrogen gas,
While constantly monitoring the column outlet gas with a cold atomic absorption type gas monitor, use a nitrogen-based test gas with a silane concentration of 1%.
Aeration was performed at 50 ml / min (superficial velocity: 1.0 cm / sec). Over time, the packed bed changed color from blue to black from upstream to downstream, and the movement of the black / blue front was observed. At 3670 minutes after the start of aeration, the position of the black / blue discoloration front reached about 10 mm from the most downstream portion of the packed bed, and the silane concentration of the outlet gas became 5 ppm. The amount of silane treated at this time was 125 liter / kg.

According to this embodiment, when cupric hydroxide is used as a silane remover, if the filling layer is made visible, the breakthrough can be detected simultaneously with the removal of silane. It is not necessary to use a separate sensing agent.

When a column made of a material the inside of which is invisible is filled with a remover composed of cupric hydroxide to remove silane, 1 is added to the most downstream portion of the packed layer of the column.
If a visual window of 0 mm or more is provided, or if a transparent column filled with cupric hydroxide for a length of 10 mm or more is connected in series downstream of the packed bed, breakthrough of the remover can be performed in advance. Can be detected. Further, cupric hydroxide can be used as a breakthrough detection agent even when a remover having no ability to detect breakthrough is used.

Example 3 Example 2 was repeated except that the test gas was a hydrogen-based arsine concentration of 1% and the column outlet gas was monitored by the same detector as in Example 1. As a result, the packed bed changes color from blue to black from upstream to downstream over time,
A black / blue front shift was observed. 455 after starting ventilation
At 0 minutes, the position of the black / blue discoloration front reached about 10 mm from the most downstream portion of the packed bed, and the arsine concentration of the outlet gas became 0.05 ppm. The amount of arsine treated at this time was 155 liters / kg.

Example 4 Example 4 was repeated except that the phosphine concentration was 1% based on hydrogen as the test gas. As a result, 3
At 870 minutes, the position of the black / blue discoloration front reached about 10 mm from the most downstream portion of the packed bed, and the phosphine concentration of the outlet gas became 0.3 ppm. The treatment amount of phosphine at this time was 132 liters / kg.

Example 5 The test gas was a nitrogen-based dichlorosilane concentration of 1%,
The procedure of Example 2 was repeated, except that the column outlet gas was monitored by a halogen monitor (halogen monitor TG-3400 manufactured by Nippon Bionics Co., Ltd.). As a result, 4
At 690 minutes, the position of the black / blue discoloration front reached about 10 mm from the most downstream part of the packed bed, and the concentration of dichlorosilane in the outlet gas became 5 ppm. The amount of dichlorosilane treated at this time was 160 liters / kg.

Example 6 Example 3 was repeated except that the test gas was a nitrogen-based tertiary butylarsine concentration of 1%. As a result, at 2640 minutes after the start of aeration, the position of the black / blue discoloration front reaches about 10 mm from the most downstream portion of the packed bed,
The tertiary butyl arsine concentration in the outlet gas is 0.03
became ppm. The amount of tertiary butyl arsine treated at this time was 90 liters / kg.

[0033]

As described above, the removing agent of the present invention can efficiently remove harmful components such as volatile inorganic hydrides, volatile inorganic halides and organometallic compounds contained in exhaust gas. It is possible to reduce the size of the reaction tube or extend the exchange period of the removing agent. Also, since it has sufficient removal ability even if the specific surface area is small, it is not necessary to carry out a fine-graining treatment or to support it on a carrier, and it is possible to reduce the manufacturing cost of the removing agent itself, which is extremely effective. Great effect.

Further, since this removing agent changes color by the reaction with harmful components, it is possible to know the breakthrough of the removing agent by monitoring the color change condition, and it is possible to surely know the replacement time. Further, by utilizing this discoloration, it can be used as a detecting agent for harmful components.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C01G 3/02 (72) Inventor Fumitaka Endo 3054-3 Shimokurosawa, Takane-cho, Kitakoma-gun, Yamanashi Nihon Oxygen Co., Ltd. (72) Inventor Shinji Ichimura 4-320 Tsukagoshi, Sachio-ku, Kanagawa Nihon Oxygen Co., Ltd. (72) Inventor Emi Yoshida 4-320 Tsukakoshi, Sachi-ku, Kanagawa Nihon Oxygen, Co. Ltd.

Claims (3)

[Claims] 1. A remover for harmful components, which comprises copper hydroxide as a main reaction component. 2. The remover for harmful components according to claim 1, wherein the copper hydroxide is crystalline copper hydroxide. 3. A detector for a harmful component gas, which comprises copper hydroxide as a main component.