JPH08155259A - Harmful gas removal method and agent - Google Patents

Abstract

(57) [Summary] [Purpose] While utilizing the property of copper hydroxide, which has a high ability to remove harmful components, it is possible to accelerate the rate of the abatement reaction and reduce the emission concentration of harmful components before breakthrough. To provide a harmful gas removing method and a harmful agent. [Structure] Exhaust gas containing a harmful component is brought into contact with a detoxifying agent obtained by adding a basic compound and / or an oxidizing agent to copper hydroxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an abatement agent for removing exhaust gas containing harmful components. More specifically, the invention relates to a volatile inorganic hydride, a volatile inorganic halide, an organic compound discharged from a semiconductor manufacturing process or the like. The present invention relates to a method and an abatement agent for removing exhaust gas containing harmful components such as metal compounds.

[0002]

2. Description of the Related Art In semiconductor manufacturing processes, volatile inorganic hydrides such as silane, arsine and phosphine, volatile inorganic halides such as chlorosilane and boron fluoride, and recently, organic metals such as alkyl compounds and alkoxides. Compounds are used as source gas. Since most of these gases are harmful, the exhaust gas containing these harmful components discharged from the semiconductor manufacturing process or the like needs to be rendered harmless before being discharged to the atmosphere.

With respect to exhaust gas containing mainly volatile inorganic hydrides, it has been conventionally practiced to bring the exhaust gas into contact with a harm-removing agent mainly composed of a metal oxide such as copper oxide to remove the harm. There is.

[0004]

However, the harm-removing agent containing a metal oxide such as copper oxide as a main component has a smaller harm-removing ability with respect to silane-based harmful components, and therefore has a higher breakthrough than other harmful components. Time is short. Therefore, it is necessary to carry out a fine-graining treatment and to make the specific surface area larger by supporting it on a carrier such as alumina, and the production of the harmful agent itself has been troublesome.

Further, in recent semiconductor manufacturing technology, CV
Organometallic compounds are increasingly used in the production of compound semiconductors by the D method (chemical vapor deposition method), but these are also harmful and need to be removed. For this reason,
It has been desired to develop a detoxifying agent that has a large ability to remove silanes and the like and that can also remove organometallic compounds and the like.

In view of such a situation, the inventors of the present invention have conducted extensive research for the purpose of developing a harm-removing agent having a sufficient harm-removing ability for silane-based harmful components. It has about 4 times the ability to remove harmful components from the system as compared to conventional copper oxide, and it is also excellent at removing volatile inorganic hydrides other than silane and organometallic compounds. It has been found to have the ability.

However, as a result of further detailed examination, when copper hydroxide is used alone for the detoxification treatment of the exhaust gas containing harmful components such as silane, before the detoxifying agent breaks through, the exhaust gas after the treatment is treated. Higher concentrations of harmful components often occurred.
It is considered that this is because the rate of the copper hydroxide removal reaction is low.

Therefore, while taking advantage of the property that copper hydroxide has a high ability to remove harmful components, it is possible to accelerate the rate of the detoxifying reaction and reduce the emission concentration of harmful components before breakthrough. Intensive research was conducted for the purpose of developing detoxification methods and detoxifying agents.

[0009]

[Means for Solving the Problems] As a result, copper hydroxide
It was found that the above problems can be solved by adding a specific additive. The present invention was made based on this finding, and the harmful gas removing method of the present invention is
It is characterized in that the exhaust gas containing a harmful component is brought into contact with a detoxifying agent containing copper hydroxide as a main component and a basic compound and / or an oxidizing agent added.

Further, the harmful gas harm-removing agent of the present invention is a harm-removing agent for effecting the harm-removing treatment of exhaust gas containing harmful components, which contains copper hydroxide as a main component and a basic compound and / or an oxidizing agent. In particular, the basic compound is a metal hydroxide (excluding copper hydroxide), a metal carbonate, a metal aluminate or an amine compound,
The oxidizing agent is a metal sulfate, a metal chloride, a metal oxide,
It is characterized in that it is a metal acetate, permanganate, chromate, nitrate, peroxide, oxygenate or peroxoate.

The main harmful components to be harmed by the present invention are:
Examples thereof include volatile inorganic hydrides, volatile inorganic halides, and organic metal compounds that are used as raw material gases in the semiconductor manufacturing process described above. As the volatile inorganic hydride,
Diborane, silane, disilane, germane, ammonia,
Examples thereof include phosphine, arsine, hydrogen sulfide, hydrogen selenide, and the like, and volatile inorganic halides include boron trifluoride, boron trichloride, silicon tetrafluoride,
Various gases including halogen gas such as dichlorosilane, trichlorosilane, silicon tetrachloride, trichloroarsine, tungsten hexafluoride, fluorine, chlorine, hydrogen fluoride, hydrogen chloride, hydrogen bromide and the like 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.

The copper hydroxide as the main component mainly means cupric hydroxide (Cu (OH) ₂ ), but it may 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. , When the reaction heat is high,
It can be used more stably. 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. Furthermore, when copper hydroxide reacts in contact with the gas to be removed and changes its color from blue to black clearly, when it is used by filling the removal cylinder, the breakthrough front progresses from the upstream side. Not only is it unnecessary to use a detection agent, but it can also be used as a detection agent for the gas to be removed, if necessary.

On the other hand, although copper hydroxide can be used alone as a scavenger of the above-mentioned harmful gas, comparing the conventional copper oxide and the copper hydroxide of the present invention with respect to the ability to remove silane under the same conditions. As shown in FIG. 1, the time until the breakthrough phenomenon in which the silane concentration in the gas after the treatment rises sharply occurs is longer for copper hydroxide than copper oxide, and the detoxifying ability is about four times as high. It turned out to be. However, copper hydroxide
It has also been found that there is a drawback that the silane concentration in the gas after the treatment before the breakthrough may reach a high level.

It is considered that the cause is that copper hydroxide has a higher proportion of components contributing to the detoxification 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 individual diameter is at least about several microns, and the reaction is about several angstroms on the surface (relative to the diameter). At most 1
(Thickness of about 1/000), only the surface of the substance contributes to the reaction, and the copper oxide inside remains unreacted, whereas in the case of copper hydroxide, the reaction proceeds to the inside of the substance. It is presumed that it is because of this. In fact, in the case of copper hydroxide, a large amount of silane can be removed even if the specific surface area is small. On the other hand, however, it is considered that when the reaction proceeds inside the copper hydroxide, the apparent reaction rate decreases, and the level of harmful components after the treatment increases.

Therefore, the present inventors investigated the detoxification behavior of copper hydroxide and conducted various experiments aimed at enhancing the reaction rate thereof. As a result, when basic compounds such as sodium hydroxide and sodium aluminate are added to copper hydroxide, not only the detoxifying ability of harmful components is slightly improved, but also harmful components after treatment before the agent breaks through. It was found that the concentration of sucrose decreased remarkably. As a result of further research, it was found that not only sodium hydroxide and sodium aluminate but also basic compounds have common effects. It was also found that the same effect can be obtained by adding a substance having an oxidizing power instead of the basic compound. Furthermore, it has also been found that the effects are not impaired even if a basic compound and an oxidizing substance are appropriately mixed and added.

That is, when a basic compound or an oxidizing agent is added to copper hydroxide, the rate of the detoxification reaction inside the copper hydroxide is enhanced for some reason, and the level of the harmful component gas concentration after the treatment is lowered. However, it became clear that it could be a practical harmful agent.

The basic compound or oxidizing agent added to the copper hydroxide may be added individually or as a mixture of plural kinds thereof, and the addition amount thereof is 100 weight% of the copper hydroxide. 0.001 to 50.0 parts by weight, and preferably 0.01 to 20.0 parts by weight, are effective. If the addition amount is less than 0.001 part by weight, there is almost no effect, and if the addition amount is less than 0.01 part by weight, no sufficient effect is exhibited.
Also, if the addition amount exceeds 20 parts by weight, the effect of addition is small, and if it exceeds 50 parts by weight, the detoxifying ability is rather lowered.

Here, the basic compound used as an additive in the present invention is a metal hydroxide, a metal carbonate, a metal aluminate or various amine compounds, and the oxidizing agent is a metal sulfate. , Metal chlorides, metal oxides, metal acetates, permanganates, chromates, nitrates, peroxides, oxyacid salts, various peroxo acid salts, etc., and one or more of these may be mentioned. Seeds can be added.

Specifically, the metal hydroxides include lithium hydroxide (LiOH) and sodium hydroxide (NaO).
H), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) ₂ ), calcium hydroxide (Ca (OH)
₂ ), strontium hydroxide (Sr (OH) ₂ ), barium hydroxide (Ba (OH) ₂ ), nickel hydroxide (Ni
(OH) ₂ ) and the like. Examples of the metal carbonate include sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), and sodium hydrogen carbonate (NaHC
O ₃ ), potassium hydrogen carbonate (KHCO ₃ ) and the like can be mentioned. The metal aluminate includes lithium aluminate (Li (AlO ₂ )), sodium aluminate (Na (AlO ₂ )), potassium aluminate (K
(AlO ₂ )), magnesium aluminate (Mg (Al
O ₂ ) ₂ ), calcium aluminate (Ca (AlO ₂ )
₂ ), strontium aluminate (Sr (Al
O ₂ ) ₂ ), barium aluminate (Ba (Al
O ₂ ) ₂ ) and the like. Further, as the amine compound, primary amine (RNH ₂ ) and secondary amine (R ₂ N
H), tertiary amine (R ₃ N), quaternary amine (R ₄ NX)
Can be mentioned. In the amine compound,
R is an alkyl group, and X represents an anion, for example, a halogen ion such as a chlorine ion.

As the oxidizer, copper sulfate (CuSO
₄ ), various metal sulfates, iron chloride (FeCl ₃ ), various metal chlorides, manganese dioxide (MnO ₂ ),
Copper oxide (CuO), diarsenic pentoxide (As ₂ O ₅ ), selenium dioxide (SeO ₂ ), ruthenium oxide (RuO ₂ ),
Metal oxides such as silver oxide (Ag ₂ O), cerium oxide (CeO ₂ ), osmium oxide (OsO ₄ ), mercury oxide (HgO), lead dioxide (PbO ₂ ), bismuth oxide (Bi ₂ O ₃ ), acetic acid Copper (Cu (CH ₃ COO) ₂ ), mercury acetate (Hg (CH ₃ COO) ₂ ), lead acetate (Pb (CH ₃ C 2
OO) ₄ ), bismuth acetate (Bi (CH ₃ COO) ₃ )
Metal acetate such as permanganate (HMnO ₄ ), sodium permanganate (NaMnO ₄ ), permanganate such as potassium permanganate (KMnO ₄ ), chromic anhydride (CrO ₃ ), chromium dichloride chromium (CrO ₂ C
l ₂ ), sodium chromate (Na ₂ CrO ₄ ), sodium dichromate (Na ₂ Cr ₂ O ₇ ), sodium chromate chromate (Na ₂ CrO ₃ Cl) and other chromates, ammonium nitrate (NH ₄ NO ₃ ), Potassium nitrate (KN
O ₃ ), nitrates such as copper nitrate (Cu (NO ₃ ) ₂ ), hydrogen peroxide (H ₂ O ₂ ), sodium peroxide (Na
₂ O ₂ ), barium peroxide (BaO ₂ ), benzoic anhydride ((C ₆ H ₅ CO) ₂ O) and other peroxides, sodium hypochlorite (NaClO), sodium hypobromite (Na
BrO), sodium hypoiodite (NaIO), sodium chlorate (NaClO ₃ ), periodate (HI)
O ₄ ), potassium periodate (KIO ₄ ), sodium perchlorate (NaClO ₄ ), oxyacid salts such as sodium hydrogen iodate (Na ₃ H ₂ IO ₆ ), sodium peroxodisulfate (Na ₂ S ₂ O) ₈ ), potassium peroxodisulfate (K ₂ S ₂ O ₈ ), sodium peroxomonosulfate (Na ₂ SO ₅ ), peroxoformic acid (HCOOOH),
Peroxo acid (CH3COOOH), peroxo acid (C ₆ H ₅ COOOH), peroxo phthalate (C
_{6 H 4 (COOH) COOOH)} , peroxy acid salts such as peroxo trifluoroacetic acid (CF ₃ COOOH), further include such nitrobenzene (C ₆ H ₅ NO ₂₎ and iodosobenzene (C ₆ H ₅ IO) be able to.

By adding the above-mentioned additives to copper hydroxide, the harmful components can be removed efficiently. In the method of the present invention, it is sufficient to fill the detoxifying agent containing the above-mentioned additive in an appropriate column, to flow the exhaust gas through the column, and to bring the exhaust gas into contact with the detoxifying agent, which can be easily carried out.

[0023]

EXAMPLES Examples and comparative examples of the present invention will be described below. Example 1 and Comparative Example 1 The following harmful agents A to D were prepared as harmful agents. A (comparative example): a commercially available powdered copper oxide is tableted to have a diameter of 3 m.
Molded into pellets of m and 3 mm in length. In addition, copper oxide is supported on an alumina carrier by a known method. B (Comparative Example): Commercially available powdered copper hydroxide molded into pellets similar to A. C (Example): To 100 parts by weight of the same copper hydroxide as in B, 0.1 part by weight of commercially available sodium hydroxide was added, thoroughly mixed and ground in a mortar, and then tableted to give pellets similar to A. Molded one. D (Example): In C, sodium hydroxide was replaced with sodium aluminate, and pellets were similarly molded.

Each of the above agents was filled in a filling cylinder having an inner diameter of 40 mm in an amount of 250 g (filling height of about 200 mm), and hydrogen gas containing 1% of silane was filled therein with an empty space velocity of 1 cm / cm.
It was shed in sec. The silane concentration at the outlet of the filling cylinder was measured with a monitor (AD-10 made by Nippon Oxygen), and the dynamic absorption amount of silane of each agent was measured from the time until the end with 5 ppm as a breakthrough point (allowable concentration), and The previous concentration was measured.

The results are shown below. Agent Dynamic absorption [l / Kg] Concentration before breakthrough [ppm] A 3 ND (Note 1) (25 to 30 (Note 2)) B 125 2.5 C 150 ND D 148 ND Note 1) ND is , Detection limit (1.0ppm) or less Note 2) When copper oxide is supported on an alumina carrier

From these results, the dynamic absorption amount of copper oxide (agent A) is 3 liters per 1 kg of the agent alone, and is about 25 to 30 liters per 1 kg of the agent when loaded on the alumina carrier. On the other hand, with copper hydroxide (agent B), the amount of 125 liters per 1 kg of the agent alone is four times or more that of the case where copper oxide is supported on the alumina carrier. However, regarding the concentration before breakthrough, agent B has not reached the breakthrough concentration (5 ppm), but 2.5 ppm
It showed a slightly higher concentration. Next, with the agent C in which sodium hydroxide was added to copper hydroxide and the agent D in which sodium aluminate was added to copper hydroxide, the amount of dynamic absorption was slightly larger than that of agent B, and the concentration before breakthrough was It can be seen that it has fallen to ND.

Example 2 Various metal hydroxides, which are basic compounds, were added to copper hydroxide to prepare the following harmful agents E to H. The parts by weight of the following additives are based on 100 parts by weight of copper hydroxide. E: 0.1 part by weight of commercially available potassium hydroxide was added to the same copper hydroxide as in Example 1B, and the mixture was sufficiently mixed and pulverized in a mortar and then similarly tableted to give a diameter of 3 mm and a length of 3 mm. Molded into pellets. F: 10 parts by weight of commercially available magnesium hydroxide was added as an additive and molded into pellets in the same manner as in E. G: 1 part by weight of commercially available calcium hydroxide was added as an additive and molded into pellets in the same manner as in E. H: 5 parts by weight of commercially available nickel hydroxide was added as an additive and molded into pellets in the same manner as in E.

The results of the same abatement test as in Example 1 using the above E to H agents are shown below. Agent Dynamic absorption amount [l / Kg] Concentration before breakthrough [ppm] E 150 ND F 149 ND G 149 ND H 147 ND From these results, each hydroxide shows dynamic absorption amount and concentration before breakthrough. It can be seen that both have the same effect of addition as sodium hydroxide.

Example 3 The following harmful agents I and J were prepared by adding various metal carbonates which are basic compounds. I: 1 part by weight of commercially available sodium carbonate was added to commercially available copper hydroxide, thoroughly mixed and ground in a mortar, and then tableted in the same manner as above to form pellets having a diameter of 3 mm and a length of 3 mm. J: Commercially available copper hydroxide, commercially available potassium carbonate 0.1%
Added in parts by weight and molded into pellets in the same manner as in I.

The following shows the results of the same abatement test as in Example 1 using the aforesaid abatement agents I and J. Agent Dynamic absorption [l / Kg] Concentration before breakthrough [ppm] I 148 ND J 148 ND From these results, even if a metal carbonate was used as the basic compound, It can be seen that both the concentration and the addition effect are similar to those of the metal hydroxide.

Example 4 Using various aluminates as basic compounds to be added to copper hydroxide, the following harmful agents KM were prepared, and the harmful effect was examined in the same manner as in Experimental Example 1. K: Molded into pellets in the same manner as in I except that 1 part by weight of commercially available potassium aluminate was added as an additive instead of sodium carbonate in the harmful agent I of Example 3. L: molded into pellets in the same manner as K except that commercially available calcium aluminate was used as an additive instead of potassium aluminate. M: Molded into pellets in the same manner as K except that commercially available barium aluminate was used as an additive instead of potassium aluminate.

Agent Dynamic absorption amount [l / Kg] Concentration before breakthrough [ppm] K 147 ND L 146 ND M 147 ND From these results, the dynamic absorption was obtained even when an aluminate was used as the basic compound. It can be seen that both the amount and the concentration before breakthrough have the same effect of addition as the metal hydroxide.

Example 5 In place of the basic compound of Example 4, 1 part by weight of triphenylamine (N (C ₆ H ₅ ) ₃ ) was added, and pellets of the harmful agent N were prepared in the same manner. The amount of dynamic absorption and the concentration before breakthrough were examined.

Agent Dynamic Absorption [l / Kg] Concentration before breakthrough [ppm] N 148 ND From these results, the addition effect of amine compounds can be seen.

Example 6 Various oxidizing agents were added to copper hydroxide to remove the following harmful agents OS.
Was prepared, and the ability to remove harmful components was examined in the same manner as in Example 1. O: 0.1 parts by weight of commercially available sodium permanganate was added to commercially available copper hydroxide, and molded into pellets similar to those in Example 1. P: A product obtained by adding 0.5 parts by weight of potassium perchlorate in place of sodium permanganate and molding into pellets in the same manner as O. Q: A product obtained by adding 1 part by weight of copper sulfate in place of sodium permanganate and molding into pellets in the same manner as O. R: 0.2 parts by weight of iron chloride was added in place of sodium permanganate, and pelletized in the same manner as O. S: Manganese dioxide was added in an amount of 5 parts by weight in place of sodium permanganate, and pelletized in the same manner as O.

Agent Dynamic Absorption [l / Kg] Concentration before breakthrough [ppm] O 150 ND P 150 ND Q 148 ND R 145 ND S 150 ND From these results, various oxidizing agents were added as additives. Also in the case, it is understood that the same addition effect is exhibited.

Example 7 Various basic compounds and various oxidizing agents were mixed and added to copper hydroxide to prepare the following harmful agents T to V, and their harmful ability was examined. T: To a commercially available copper hydroxide, 15 parts by weight of magnesium hydroxide and 0.1 part by weight of sodium permanganate were added, thoroughly mixed and ground in a mortar, and then tableted to have a diameter of 3 m as described above.
Molded into pellets of m and 3 mm in length. U: 1 part by weight of sodium carbonate and 0.2 part by weight of sodium permanganate were added and molded into pellets similar to T. V: 0.5 parts by weight of calcium aluminate and 0.3 parts by weight of sodium permanganate were added and molded into pellets similar to T.

Agent Dynamic Absorption [l / Kg] Concentration before breakthrough [ppm] T 155 ND U 154 ND V 155 ND Thus, even when the basic compound and the oxidant are mixed and added, A good addition effect was obtained.

Example 8 and Comparative Example 2 Detoxifying agent V of Example 7 and detoxifying agents A and B of Comparative Example 1
Was used, and the same operation was performed except that the harmful component was changed to silane and arsine was used. The results are shown below. Agent Dynamic absorption [l / Kg] Concentration before breakthrough [ppm] A 70 ND B 120 0.04 V 150 ND

Example 9 and Comparative Example 3 In the harmful agents A to D of Example 1 and Comparative Example 1 and the harmful agent T of Example 7, 1% of trichlorsilane, which is an inorganic halide as a gas containing harmful components. Detoxification treatment of nitrogen gas (gas X) containing 1%, hydrogen gas containing 1% of metal alkyl compound trimethylaluminum (gas Y), and hydrogen gas containing 1% of metal alkoxide tetraethoxysilane (gas Z), The dynamic absorption amount [1 / Kg] was measured in the same manner as in each of the above-mentioned examples. The results are shown below.

Dynamic Absorption [l / Kg] Agent Gas X Gas Y Gas Z A 455 B 110 100 90 C 160 130 135 135 D 155 125 140 T 160 160 140 145

[0042]

As described above, according to the present invention,
Not only is the ability of copper hydroxide to remove harmful components improved, but the concentration of harmful components after the treatment before the agent breaks through is significantly reduced, and effective removal treatment can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the detoxifying ability of copper hydroxide and copper oxide.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01D 53/68 B01D 53/34 120 D 134 Z

Claims (4)

[Claims] 1. A method of removing harmful gases, which comprises contacting exhaust gas containing harmful components with a harmful compound containing copper hydroxide as a main component and containing a basic compound and / or an oxidizing agent. 2. A detoxifying agent for detoxifying exhaust gas containing a detrimental component, characterized by containing copper hydroxide as a main component and adding a basic compound and / or an oxidizing agent. Harmful agent. 3. The harmful component according to claim 2, wherein the basic compound is a metal hydroxide (excluding copper hydroxide), a metal carbonate, a metal aluminate or an amine compound. Harmful agent. 4. The oxidizing agent is a metal sulfate, a metal chloride, a metal oxide, a metal acetate, a permanganate, a chromate, a nitrate, a peroxide, an oxygenate or a peroxoate. The harm-removing agent for harmful components according to claim 2.