JP2008302338A - Detoxifying agent for metal hydride-containing exhaust gas, and detoxifying method for metal hydride-containing exhaust gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detoxifying agent and a detoxifying method showing a high detoxifying capacity, in detoxifying treatment of metal hydride-containing exhaust gas generated in a semiconductor manufacturing process. <P>SOLUTION: In relation to the detoxifying agent for metal hydride-containing exhaust gas and a detoxifying method, a mixture of compounds is molded containing any one or two or more kinds of a metal oxide, a metal hydroxide, a metal carbonate, or a metal basic carbonate, ammonia is absorbed in the molding to form the detoxifying agent, and the metal hydride-containing exhaust gas is passed through the detoxifying agent to detoxify the gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a detoxifying agent and detoxification method for metal hydride-containing exhaust gas, and more particularly to a detoxifying agent and detoxification method for metal hydride-containing exhaust gas generated in a semiconductor manufacturing factory or a liquid crystal manufacturing factory.

  In semiconductor manufacturing factories, various metal hydride gases and halide gases such as silane, phosphine, and arsine are used during the manufacturing process. Since these gases are flammable and / or harmful, the exhaust gas containing them cannot be released into the atmosphere as it is for environmental conservation, and there are no treatments to eliminate the danger or harm. is necessary.

  There are a wet method and a dry method for exhaust gas treatment, and the former is a method of cleaning exhaust gas with a chemical solution. On the other hand, in the latter, exhaust gas is circulated through a packed column of a granular solid processing agent, and the hazardous and harmful gas is separated by chemical action between the gas to be removed and the processing agent, that is, adsorption and / or chemical reaction. It is a detoxifying method and is often performed in the treatment of exhaust gas containing metal hydride or exhaust gas containing halide gas.

  There are many patents for metal hydride-containing exhaust gas treatment agents, and a detoxifying agent made of a metal oxide (see Patent Document 1), a detoxifying agent made of a metal hydroxide, a metal carbonate or a basic metal carbonate. (See Patent Documents 2, 3, and 4), a detoxifying agent obtained by modifying a metal hydroxide, metal carbonate, or basic metal carbonate with a basic compound such as an alkali metal (see Patent Documents 5 and 6), etc. Has been.

  However, the detoxifying agent composed of metal hydroxide, metal carbonate or basic metal carbonate has excellent detoxifying ability, but it has higher detoxifying ability as the amount of special gas used increases with recent technological progress. Therefore, the amount of exhaust gas treated per volume of the detoxifying agent as described above is no longer sufficient.

  Similarly, the amount of exhaust gas treated per volume of the detoxifying agent is not sufficient for a detoxifying agent obtained by modifying a metal hydroxide, metal carbonate or basic metal carbonate with a basic compound such as an alkali metal. In addition, there is a step of molding after mixing the abatement component powder and strong alkali component together, and when producing in large quantities on an industrial scale, there is a safety problem due to the use of strong alkali. appear. In addition, in order to implement safety measures, various capital investments such as a closed system are required, resulting in high production costs.

JP 05-269339 A Japanese Patent Application Laid-Open No. 06-319945 Japanese Patent Application Laid-Open No. 08-192024 Japanese Patent No. 26049991 Japanese Patent Laid-Open No. 08-155259 JP 2002-136634 A

  An object of the present invention is to provide a detoxifying agent and a detoxifying method exhibiting high detoxifying ability in the detoxification treatment of exhaust gas containing metal hydride generated in a semiconductor manufacturing process.

  In the study conducted by the present inventors in order to solve the above-mentioned problems, ammonia is absorbed in a molded body of a metal hydroxide, a metal carbonate, or a metal basic carbonate or a mixture of these compounds. The present invention was completed by finding that the detoxifying agent made has excellent detoxifying performance for exhaust gas containing metal hydride.

  That is, the present invention is characterized in that ammonia is absorbed in a molded body of any one of a metal oxide, a metal hydroxide, a metal carbonate, or a metal basic carbonate, or a mixture of two or more of these compounds. It is a metal hydride-containing exhaust gas abatement agent.

  More specifically, the metal component of the molded body of any one of metal oxide, metal hydroxide, metal carbonate, or metal basic carbonate or a mixture of two or more of these compounds is copper, iron, cobalt, A metal hydride-containing exhaust gas abatement agent characterized by being at least one metal component selected from the group consisting of nickel, manganese, zinc, and chromium.

  Furthermore, it is a metal hydride-containing exhaust gas abatement agent characterized in that the ammonia content is 0.1 to 5.0% with respect to the total weight of the abatement agent.

  Moreover, the ammonia to be absorbed is an ammonia gas, which is a metal hydride-containing exhaust gas abatement agent.

  In addition, the treatment method of the present invention comprises molding one kind of a metal oxide, metal hydroxide, metal carbonate, or metal basic carbonate, or a mixture of two or more of these compounds, and adding ammonia to the molded body. This is a method for removing metal hydride-containing exhaust gas, which comprises contacting an exhaust gas containing a metal hydride after absorbing water.

  Ammonia is a method for removing metal hydride-containing exhaust gas characterized by being absorbed in the gas phase.

  The detoxifying agent of the present invention is applied to detoxification of exhaust gases containing various metal hydrides such as silane, phosphine, and arsine generated in a semiconductor manufacturing factory or a liquid crystal manufacturing factory. The detoxifying agent of the present invention has high utility value in operation because it can absorb metal hydride gas efficiently by adsorbing ammonia in a gas phase to a metal compound molded body and has a large absorption capacity.

  The present invention relates to a detoxifying agent in which ammonia is absorbed in a molded body of any one of a metal oxide, a metal hydroxide, a metal carbonate, or a metal basic carbonate, or a mixture of two or more of these compounds. It is. Here, the metal compound that forms the main component of the detoxifying agent is a molded product of metal oxide, metal hydroxide, metal carbonate, basic metal carbonate or a mixture thereof, and its metal component is stable. Any metal can be used as long as it can be present, but copper, iron, cobalt, nickel, manganese, zinc, chromium, etc., which are usually easily available and inexpensive, are advantageously used.

  In addition, as the metal compounds, commercially available oxides, hydroxides, carbonates, or basic carbonates can be used. Alternatively, after the metal salts are made into an aqueous solution, a neutralization reaction with an aqueous alkali compound solution is performed. It can also be produced and used by the precipitation method to be produced. As the alkali compounds, it is preferable to use sodium, potassium hydroxide, carbonate, or aqueous ammonia. The precipitate obtained by the neutralization reaction is washed with water, filtered and dried.

  Here, as for the metal compounds, both the above-mentioned commercially available products and those produced by the precipitation method may be used not only as a single compound but also as a mixture. In the case of compounds by the precipitation method, in the case of use as a mixture, a compound obtained by precipitating the compound alone may be mixed, but it is preferable to obtain a precipitate containing a plurality of components by the coprecipitation method.

  The content of ammonia is in the range of 0.1% to 5.0% with respect to the total weight of the pesticide, and if the content is 0.1% or less, the metal hydride removal capability is not sufficiently improved. In addition, if the amount is 5.0% or more, not only a further improvement in treatment performance is observed, but also saturation adsorption is reached, which is not realistic.

  In the case of using a commercial product as a metal compound, a molded product, that is, a powdered product, the molded product, or a granulated granule after molding is used. After completion of kneading with the metal compound, a molded product that is formed into a molded product by extrusion or tableting, or a molded product as a crushed product after molding is used. Here, silica, alumina, magnesia, or other inorganic binders effective for improving the strength can be added to the treating agent as necessary in order to ensure mechanical strength that can withstand use.

  As a method of absorbing ammonia into the metal compounds, ammonia gas can be circulated and absorbed in a molded body such as a powdery product, molded product, or granule as described above. The ammonia gas concentration can be from 0.1% to 100%.

  Metal hydroxide, metal carbonate, metal basic carbonate or a mixture of these compounds is packed in a flow-through packed tower, pre-contacted with ammonia gas, and then contacted with exhaust gas containing metal hydride. Hydride gas is detoxified.

  Examples of metal hydride gases that can be detoxified by the present detoxifying agent include silane, arsine, phosphine, disilane, diborane, hydrogen selenide, germane, dichlorosilane, and the like.

  The inventors of the present invention filled the detoxifying agent obtained by a series of operations into a stainless steel flow reactor, and circulated a reducing gas containing silane, phosphine, and germane as a metal hydride gas to the reactor. In addition, the metal hydride containing gas leakage amount in the exit gas was measured and monitored by a break monitor (manufactured by Bionics), thereby performing a detoxification performance measurement test of the metal hydride-containing gas at room temperature.

  As a result, it is superior in detoxifying ability (L / kg) compared to metal oxides, metal hydroxides, metal carbonates and basic metal carbonate-based treatment agents that do not contain ammonia, and in the outlet gas for a long time. The present invention was completed by confirming that no metal hydride was detected. That is, the detoxifying agent that has absorbed ammonia according to the present invention has a detoxifying ability of 30 to 42 L / kg, which is about 1.4 times that of the treatment agent that does not absorb ammonia, and metal hydrogen in the outlet gas. A detoxifying agent having a very excellent detoxifying ability was obtained over a long period of time of about 1.4 times until the detection of the chemical.

  In addition, the detoxifying agent in which ammonia is absorbed in the molded body of the metal compound of the present invention has 1.4 times the detoxifying ability compared to the processing agent molded after mixing the basic compound with the metal compound in advance. The time until the detection of the metal hydride in the outlet gas was about 1.4 times.

  Next, the content of the present invention will be described in more detail by way of examples, but the present invention is not limited to these. The performance evaluation of the present pesticide was carried out by measuring the detoxification performance of the metal hydride gas contained in nitrogen gas after ammonia gas was absorbed before the detoxification performance measurement. Ammonia absorption and measurement are performed by a normal pressure flow type reaction apparatus, and the apparatus, conditions, and operation method are as follows.

(Ammonia gas absorption conditions)
Measurement condition
GHSV: 500 hr ⁻¹
Pressure: Normal pressure
Reaction temperature: normal temperature
Reaction gas composition: Ammonia 1%
N2 balance

(Metal hydride gas abatement performance measuring equipment and measurement conditions)
Detoxification performance measuring device: Normal pressure flow reactor Reaction tube size: Inner diameter 28mm, Length 700mm
Measurement condition
Amount of pesticide used: 60cc (filling height 100mm)
GHSV: 300 hr ⁻¹
Pressure: Normal pressure
Reaction temperature: normal temperature
Reaction gas composition: SiH4 (silane) 1%
N2 balance

(Metallic hydride gas abatement performance measurement operation method and abatement performance calculation method)
60 cc of the detoxifying agent was packed in the reaction tube so as to have a filling height of 100 mm and placed in a measuring device, and then a metal hydride gas diluted with nitrogen was circulated through the packed bed of detoxifying agent. After starting the gas flow, the metal hydride gas leakage into the reaction tube outlet gas was measured and monitored with a break monitor (manufactured by Nippon Bionics), and the cumulative amount of silane that flowed in until the outlet concentration reached 5 ppm was determined. The amount was converted per 1 kg of the treatment agent. Specifically, the detoxification performance of the metal hydride gas was calculated from the measurement result by the following formula (1).

(Calculation method for metal hydride gas removal performance of treatment agents)
Detoxification performance (L / kg) = A × (B / 100) × (C / E) (Formula 1)
Here, A: Measurement gas flow rate (L / min.)
B: Metal hydride gas concentration (volume%)
C: Cumulative gas circulation time (min.) Until the outlet concentration of the metal hydride gas reaches a predetermined concentration
E: Treatment agent filling amount (kg)

Example 1
Commercially available basic copper carbonate was used as the metal compound, and after adding 40 g of pure water to 200 g of basic copper carbonate and mixing well in a kneader, the mixture was extruded to a size of 3 mm in diameter and dried at 120 ° C. The obtained molded body was filled in a reaction tube, and ammonia gas was circulated for 285 minutes. In calculation, 2% ammonia is absorbed with respect to the detoxifying agent. Table 1 shows the silane abatement performance results of the abatement agent thus prepared.

Example 2
Commercially available basic copper carbonate as a metal compound was compacted and granulated, and tableting was performed to obtain a tablet of 4.5 mm × 3 mm. The obtained molded body was filled in a reaction tube, and ammonia gas was circulated for 130 minutes. In calculation, 1% ammonia is absorbed with respect to the detoxifying agent. Hereafter, it carried out like Example 1 and the result was shown in Table 1.

Example 3
Copper sulfate was used as an aqueous solution, and a basic copper carbonate precipitate was obtained by a neutralization reaction with sodium carbonate prepared accordingly. Next, impurities were sufficiently removed by washing with water, followed by filtration and drying at 120 ° C. to obtain basic copper carbonate. It carried out like Example 1 except having used the obtained basic copper carbonate. The ammonia gas was circulated for 150 minutes, and the calculated value was absorbed by 1.2%. The results are shown in Table 1.

Example 4
Precipitation of a composite compound of copper and manganese by a neutralization reaction between an aqueous solution in which 275 g of copper sulfate and 214 g of manganese sulfate are dissolved in 6 L of pure water and an alkaline aqueous solution in which 280 g of sodium carbonate prepared according to this is dissolved in 8 L of pure water. I got a thing. Subsequently, the impurities were sufficiently removed by washing with water, followed by filtration, drying at 120 ° C., and baking at 300 ° C. to obtain copper oxide and manganese oxide. The same procedure as in Example 1 was performed except that the obtained composite oxide of copper oxide and manganese oxide was used. The ammonia gas was circulated for 270 minutes, and the calculated value was absorbed by 1.7%. The results are shown in Table 1.

Example 5
A composite compound of iron and manganese by a neutralization reaction between an aqueous solution in which 480 g of iron sulfate and 160 g of manganese sulfate are dissolved in 2 L of pure water and an alkaline aqueous solution in which 350 g of sodium carbonate prepared according to this is dissolved in 1.7 L of pure water. A precipitate was obtained. Subsequently, the impurities were sufficiently removed by washing with water, followed by filtration, drying at 120 ° C., and baking at 500 ° C. to obtain iron oxide and manganese oxide. The same operation as in Example 1 was performed except that the obtained composite oxide of iron oxide and manganese oxide was used. The ammonia gas was circulated for 130 minutes, and the calculated value was absorbed by 1.0%. The results are shown in Table 1.

Example 6
A composite compound of copper and zinc is obtained by a neutralization reaction between an aqueous solution in which 280 g of copper sulfate and 160 g of zinc sulfate are dissolved in 0.8 L of pure water and an alkaline aqueous solution in which 240 g of sodium carbonate prepared according to this is dissolved in 3 L of pure water. A precipitate was obtained. Subsequently, the impurities were sufficiently removed by washing with water, followed by filtration, drying at 120 ° C., and baking at 300 ° C. to obtain copper oxide and zinc oxide. The same procedure as in Example 1 was performed except that the obtained composite oxide of copper oxide and zinc oxide was used. The circulation of ammonia gas was performed for 90 minutes, and 0.5% was absorbed as a calculated value. The results are shown in Table 1.

Comparative Examples 1-6
In Examples 1 to 6, experiments were performed in the same manner as in Examples 1 to 6, except that ammonia gas was not circulated. The results are shown in Table 1.

Comparative Example 7
Using commercially available basic copper carbonate as a metal compound, an aqueous solution obtained by dissolving 2 g of sodium hydroxide in 40 g of pure water was added to a basic copper carbonate 200 g in a kneader and mixed sufficiently, and then extruded to a size of 3 mm in diameter. Dry at 120 ° C. The obtained sodium hydroxide-impregnated basic copper carbonate was tested in the same manner as in Examples 1 to 6, except that ammonia gas was not passed. The results are shown in Table 1.

  From the results of Table 1, the detoxifying agent in which ammonia gas was circulated through a molded body of metal oxide, metal hydroxide, metal carbonate, and basic metal carbonate compound was a metal oxide that did not circulate ammonia gas, Compared with the detoxifying agent of metal hydroxide, metal carbonate and basic metal carbonate compound, the detoxifying ability (L / kg) is excellent, and the metal hydride is in the outlet gas for a long time. It was proved not to be detected.

  Further, even when compared with a detoxifying agent obtained by modifying a metal hydroxide, a metal carbonate or a basic metal carbonate with a basic compound such as an alkali metal, the detoxifying ability was improved.

Claims (6)

  Metal hydride content, characterized in that ammonia is absorbed in a molded body of any one of metal oxide, metal hydroxide, metal carbonate, or metal basic carbonate or a mixture of two or more of these compounds Exhaust gas detoxifier.   The metal component of the molded body of a mixture of one or more of these compounds of metal oxide, metal hydroxide, metal carbonate, or metal basic carbonate is copper, iron, cobalt, nickel, manganese, 2. The metal hydride-containing exhaust gas abatement agent according to claim 1, wherein the metal hydride-containing exhaust gas abatement agent is at least one metal component selected from the group consisting of zinc and chromium.   The metal hydride-containing exhaust gas abatement agent according to claim 1 or 2, wherein the ammonia content is 0.1 to 5.0% with respect to the total weight of the abatement agent.   The metal hydride-containing exhaust gas abatement agent according to any one of claims 1 to 3, wherein the ammonia to be absorbed is ammonia gas.   A metal oxide, metal hydroxide, metal carbonate, or metal basic carbonate is molded into one or a mixture of two or more of these compounds, and after the ammonia is absorbed in the molded body, a metal hydride is contained. A metal hydride-containing exhaust gas abatement method characterized by contacting exhaust gas. 6. The exhaust gas abatement method for metal hydride according to claim 5, wherein ammonia is absorbed by the gas phase.