JP2001353420A - Recovery of semiconductor special material gas from exhaust gas generated from compound semiconductor manufacturing equipment - Google Patents

Abstract

(57) [Problem] To recover a V-group semiconductor special material gas from exhaust gas discharged without being consumed in each process related to compound semiconductor manufacturing [Solution] Consumed in each process related to compound semiconductor manufacturing For recovering a group V semiconductor special material gas from exhaust gas discharged without exhaust gas, the device includes IIA, IIB and / or IIB contained in the exhaust gas.
Or an apparatus for substantially removing a group IIIB element, an apparatus for concentrating a group V semiconductor special material gas from exhaust gas thereof, and a cylinder for charging and recovering the concentrated group V semiconductor special material gas and further concentrating the same. Characteristic device for collecting V-group semiconductor special material gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the recovery of a V-group semiconductor manufacturing gas semiconductor special material gas from exhaust gas generated from a compound semiconductor manufacturing apparatus.

[0002] Compound semiconductors have a wide range of applications as electronic devices covering physical properties that cannot be obtained with Si as direct transition semiconductors, and further development is desired in the future. However, as a hindrance to its development and prosperity, the cost of semiconductor special material gas itself such as arsine and phosphine as a semiconductor manufacturing gas, the processing cost of exhaust gas, environmental problems during production, and disposal of arsine and phosphine Environmental problems are getting serious.

[0003]

2. Description of the Related Art The following technologies are known as conventional exhaust gas treatment devices and recovery devices. (1) Exhaust gas treatment equipment is roughly classified into neutralization reaction or oxidative removal chemical liquid treatment abatement type, reactant abatement type is a neutralization reaction type, and combustion abatement is classified into an oxidation type. . For gaseous species that do not contain heavy metals, a combustion abatement type is being implemented. The exhaust gas removing apparatus shown in FIG. 1 oxidizes exhaust gas with potassium permanganate. In the chemical treatment abatement type shown in FIG. 1, the waste liquid is disposed as containing a heavy metal, and the reactant abatement type shown in FIG. 2 is often disposable, and after being used and sufficiently cured, the soil is removed. Buried inside. As a general burn-off type shown in FIG. 3, a flame is generated using air and flammable gas, exhaust gas is introduced into the flame, treated as an oxide, and discarded. (2) As a recovery apparatus, global warming gas emitted from a semiconductor process or the like is limited to a target and is recovered by a method such as cryogenic separation or membrane separation. The conventional technology has the following problems. (I) Since all of the current exhaust gas treatment apparatuses, ie, the chemical liquid treatment abatement type, the reactant abatement type, and the combustion damage type, change into a stable reaction product, it is desirable to use V effectively.
Reconversion to group gas requires capital investment and a considerable amount of energy. In addition, when the required V-group semiconductor material gas is of high purity, it is necessary to purify it using an enormous amount of energy and zero emission is inevitable, and the exhaust gas is currently disposed of as a reactive organism. . (Ii) In addition, heavy metals are contained in these reactive organisms, which are buried in the soil after curing, but problems still remain in consideration of environmental conservation. . (Iii) The current recovery equipment is aimed at preventing global warming, and the type of gas handled is C
It is limited to stable gases such as O ₂ , CF ₄ , C ₂ F ₆ , and in extreme terms, it is about CF ₄ , C ₂ F ₆ , and it is toxic, flammable, decomposes and produces compounds such as compound semiconductor materials It is not a level of technology that can overcome materials that also have physical properties such as instability.

[0004]

At present, arsine is not particularly manufactured in Japan. It relies entirely on imports from the United States. However, in the United States, it is extremely difficult to expand the production facilities for arsine and phosphine due to environmental problems. In the production of compound semiconductors, semiconductor special material gases such as arsine and phosphine are used in 10
Only -30% is consumed in the process and the rest is discarded. Unused semiconductor special material gas is neutralized and discarded, but it is inevitable to soil contamination. .

[0005]

SUMMARY OF THE INVENTION It has become an obligation to recover semiconductor special material gas which has been discarded in the past. The present invention is a technology for recovering and effectively utilizing unreacted effective substances in exhaust gas as a solution to the problem, and has changed the current state of exhaust gas treatment to zero emission. It relates to a semiconductor material recovery device. In addition, it goes without saying that the present invention is not only for resource reuse but also for reducing the burden on the environment.

The present invention relates to an apparatus for recovering a group V semiconductor special material gas from exhaust gas which is not consumed and exhausted in each process relating to compound semiconductor production.
The device is equipped with IIA, II contained in the exhaust gas.
Apparatus for substantially removing Group B and / or IIIB elements, apparatus for concentrating Group V semiconductor special material gas from exhaust gas, and further enrichment with a cylinder for filling and recovering concentrated Group V semiconductor special material gas The present invention relates to an apparatus for recovering a compound of a group V element, which includes a cylinder having a function of performing the above-described operation and a cylinder cabinet containing the cylinder. The aim is to achieve zero emissions by making effective use of the recovered resources. It is an object of the present invention to provide a compound semiconductor material recovery apparatus that achieves not only effective use of resources and prevention of depletion but also environmental consideration.

The present invention also relates to a method for recovering a V-group semiconductor special material gas from an exhaust gas which is not consumed and exhausted in each process relating to the production of a compound semiconductor. IIA,
A step (a) for substantially removing the IIB and / or IIIB elements, a step (b) for concentrating the group V semiconductor special material gas from the exhaust gas, and a cylinder filling and collecting the concentrated group V semiconductor special material gas And further comprising a step (c) of further concentrating the gas.

The present invention also relates to an adsorption tower for removing a group IIA, IIB and / or IIIB element from exhaust gas discharged without being consumed in each process relating to the production of a compound semiconductor, wherein the adsorption tower comprises a molecular sieve 3A,
Molecular sieves such as Molecular Sieve 13X,
It is to provide an adsorption tower packed with alumina or silica saturated with water.

The present invention also provides a method for removing Group IIA, IIB and / or IIIB elements from exhaust gas which is not consumed and exhausted in each process relating to the production of compound semiconductors. It is to provide a method comprising passing a saturated silica layer and then passing the exhaust gas through a molecular sieve layer such as molecular sieve 3A or 13X. .

The present invention is also directed to a cylinder for recovering arsine from a mixed gas containing arsine and nitrogen separated from exhaust gas discharged without being consumed in each process related to the production of compound semiconductor, wherein a valve used for the cylinder is It has an inlet for the mixed gas, an outlet for discharging a gas having a low adsorptivity in order to enable the concentration operation, and an outlet for the concentrated or adsorbed group V-based semiconductor material gas. The purpose is to provide a cylinder cabinet in which the filter is installed.

It is preferable that the apparatus for concentrating the V-group semiconductor special material gas is performed by TPSA (temperature-pressure swing adsorption). PSA (pressure swing adsorption) separates a mixed gas by increasing the pressure of the adsorption tower to selectively adsorb certain components in the gas, and lowering the adsorption tower to desorb the components adsorbed by the adsorbent. . TSA (temperature swing adsorption) lowers the temperature of the adsorption tower to selectively adsorb certain components in the gas, raises the temperature of the adsorption tower to higher temperatures to desorb the components adsorbed by the adsorbent, and separates the mixed gas. Do.

[0012] TPSA is to raise and lower the temperature and pressure,
This is to separate the mixed gas. In the operation of the TPSA of the present invention, the pressure in the adsorption tower is increased at room temperature (preferably 2
８8 kg / cm ₂ · G) to perform adsorption of the group V semiconductor special material gas. Then, the pressure is reduced to desorb the gas. The temperature is then increased to desorb the gas. The introduction of nitrogen during the temperature rise promotes the desorption of the gas.

The removal of group 11A, 11B and / or 111B elements may be carried out using a catalyst such as Al, Ni, CaO or stainless steel, or can be removed by adsorption with an adsorbent. Examples of the adsorbent are alumina, molecular sieve and the like. Particularly, when water-saturated silica is used in the former stage of the adsorption tower, it is preferable to use molecular sieve 3A or 13X in the latter stage of the adsorption tower. In this case, the 11A, 11B and / or 111B group elements are removed in the first stage, and the moisture in the gas is removed in the second stage.

According to the present invention, an apparatus for recovering each element in an organometallic compound contained in exhaust gas discharged without being consumed in each process relating to the production of a compound semiconductor is provided with a V-group system. Since the semiconductor material gas is provided before the concentration, the concentration of the organic metal compound in the exhaust gas is reduced to II.
A, IIB and IIIB elements are selectively recovered in the pre-stage, which allows V
It is possible to prevent the performance of the concentrator from deteriorating the group semiconductor material gas, and to remove IIA, II and IIIB in the organometallic compound contained in the exhaust gas which is not consumed and discharged in each process relating to the production of the compound semiconductor. Compound semiconductor materials such as group-group elements and group V-based semiconductor material gases can be recovered, and resources can be reused and the environment can be considered.

[Embodiments] Preferred embodiments of the present invention will be described below. The recovery of arsine is described below, but phosphine can be recovered in the same manner. (Embodiment 1) FIG. 4 shows a configuration of a compound semiconductor material recovery apparatus from exhaust gas 1 which is exhausted without being consumed in each process relating to compound semiconductor production. The composition in the exhaust gas is a few ppm of organometallics, a few percent of arsine, 30-70% nitrogen and the balance hydrogen. Nitrogen is a carrier gas used in semiconductor manufacturing for purposes such as diluting exhaust gases or sealing pumps.

The exhaust pipe 2 is provided with an oxygen concentration meter 3 and a detector 4 for flammable or corrosive gas such as chlorine or fluorine. Oxygen, chlorine-based, and fluorine-based gases are necessary measures to maintain safe and constant performance because the exhaust gas has unstable physical properties such as combustible gas, decomposition and generation of compounds. When oxygen, chlorine-based, or fluorine-based gas is detected, the damper 5 operates, and the exhaust gas 1 is discharged to the conventional abatement equipment 6. In the meantime, the compound semiconductor material recovery equipment is shut down urgently,
After the performance and process status are confirmed by the microprocessor and any safety is confirmed, the system is restarted.
At the time of steady operation, the exhaust gas passes through a catalyst or adsorbent bed 8 for removing 11A, 11B and / or 111B group elements (hereinafter referred to as MO (organic metal compound)), MO is removed, and pressurized by a compressor 9. You.

Next, the exhaust gas is introduced into an adsorption tower 10 packed with zeolite as a preferred adsorbent, and FIG.
Although five adsorption towers are shown, the number of adsorption towers may be arbitrary. In the adsorption tower 10, arsine in the exhaust gas is concentrated by TPSA. 11 is a valve. Reference numeral 12 denotes an arsine densitometer. The arsine concentration meter 12 measures the concentration of arsine in the exhaust gas before entering the adsorption tower and the concentration of arsine in the exhaust gas after leaving the adsorption tower. The line 15 is sent to the conventional arsine elimination device 6 for safety when any abnormality occurs.

The preferred operation for the concentration of arsine with TPSA in an adsorption tower is one adsorption tower at room temperature at 0.99 MPa.
The voltage is increased to a. The pressure is then reduced to effect the desorption of arsine. Next, the temperature of the adsorption tower is raised to an upper limit of 170 ° C. to further desorb the arsine. At this time, introduction of nitrogen further promotes desorption of arsine. The exhaust gas is introduced into the inlet 7 of the recovery device,
To 0.99 MPa, and introduced into the device 8 for recovering IIB, IIA and IIIB elements in the organometallic compound, and then the V-group semiconductor via the device 10 for concentrating the V-group semiconductor material gas. The material gas is concentrated, the pressure is increased by a vacuum pump supporting the desorption operation, the pressure buffer buffer tank 18 and the compressor 19, and the high concentration V-group semiconductor material gas is filled in the cylinder 14 for filling and collecting and further concentrating. You.
Note that the device 8 for recovering the organometallic compound may be provided at a position before the device 10 for concentrating the group V-based semiconductor material gas, and may be provided at a position before the compressor 9. (Example 2) FIG. 5 shows that IIA, II
1 shows an apparatus 20 for recovering Group B and IIIB elements.
The pressurized exhaust gas from the semiconductor manufacturing apparatus is introduced from 21a. Packing tower 24 via valves 22 and 23
To a device 35 for concentrating the group V semiconductor material gas through valves 26 and 28
It flows to. If the adsorption capacity is reduced, regeneration or replacement is required. Local reproduction is not impossible.
When regenerating or replacing the packed tower 24 containing the adsorbent 36, gas replacement with an inert gas is necessary. In this case, the inert gas is introduced from the valve 37. Inert gas is passed through valves 25,23,26,27
(Not shown). When adsorbing the MO element in the packed tower 24, the valves 21a, 22.23, 26, 28
Shall be open. In the case of regeneration or replacement of the packed tower 24,
The regeneration gas such as nitrogen gas is sent to the abatement apparatus through the valve 23, the packed tower 24, and the valves 26 and 27 after the valve 22 is closed. In this case, the valve 28 is closed and the packed tower 38 is used. After completion of the purging, the device is separated from the device for recovering the IIA, IIB and IIIB elements in the organometallic compound, and is replaced with a new one prepared in advance or a recycled one having the same specification. Used ones are
Recycle at the factory and recycle heavy metals for reuse. afterwards,
The packed tower 24 is exchanged. In the meantime, the same operation is performed using the packed tower 39.

The adsorbent 36 contained in the packed towers 24 and 39
And 38 as alumina, silica gel, silicon carbide,
An inorganic porous material such as activated carbon and a molecular sieve were employed. (Embodiment 3) The adsorbent 36 has a large effective surface area, and IIA, I in the organometallic compound in the presence of the organometallic compound material in the exhaust gas and the group V-based semiconductor material gas.
It is required to have selectivity in the adsorption characteristics of the IB and IIIB elements and the group V-based semiconductor material gas. FIG.
The evaluation results of silica gel and alumina are shown in FIG. DMZn as a group II organometallic compound gas and TMGa, TMAl and TMIn as a group III organometallic compound gas each containing 200 ppm (same volume% or less) 1
% V group semiconductor material gas AsH ₃ + about 24% hydrogen + 75
% Four kinds of gas nitrogen was supplied at a linear velocity per 10 cm, silica gel, from the adsorption-breakthrough characteristics of the organometallic compound to the alumina, in which to determine the amount of adsorption of the organometallic compound and AsH _3. The evaluation was performed on PH ₃ instead of AsH ₃ , and the amount of adsorption of PH ₃ itself increased slightly, but the amount of adsorption in the organometallic compound hardly changed. This proved that alumina and silica gel were effective as the adsorbent 36. (Example 4) Further, the measurement of the amount of adsorption of the organometallic compound of the adsorbent 36 and the 1% group V-based semiconductor material gas was performed using G
Using C-MS (Gas Chromatography Mass Spectroscopy), the amount of the organic metal compound and its dimer, methane, ethane, and AsH ₃ were observed and the detection amount was observed. After the start of the measurement, no organometallic compound is observed, but methane and ethane are observed. After a while AsH ₃ was observed,
Subsequently, after a sufficient time, TMGa was observed, and at the same time, a dimer was also observed. FIG. 7 shows the result of measuring TMGa using alumina as the adsorbent 36. From the fact that methane and ethane were observed despite the supply of TMGa, it was clear that TMGa was decomposed from the beginning and that Ga was adsorbed, indicating that it was a chemical adsorption. At the same time, the surface of the adsorbent after breakthrough was measured by X-ray photoelectron spectroscopy to determine the chemical adsorption.
Was observed, and it was found that it was chemisorption. Example 5 An organometallic compound is extremely reactive and unstable, and in order to efficiently recover a group V-based semiconductor material gas, IIA, IIB, I
It is necessary to carefully consider the location of the device for recovering the IIB-based element. The residue from which the organometallic compounds in the exhaust gas are removed becomes a carrier gas for semiconductor processes such as trace amounts of methane, hydrogen, and nitrogen, and a group V-based semiconductor material gas.
In order to efficiently recover the group V-based semiconductor material gas, it is necessary to perform a concentration operation for selectively storing the group V-based semiconductor material gas to a certain concentration, storing the gas at a high concentration, and then releasing the gas. That is, it is necessary to select an adsorbent that selectively adsorbs a low-concentration group V-based semiconductor material gas contained in the process carrier gas and desorbs as easily as possible. Adsorption and desorption are contradictory and require a certain level of compromise. For this reason, synthetic zeolite was selected as the adsorbent of the apparatus 10 for concentrating the group V semiconductor material gas. Zeolites are crystalline aluminosilicates based on alumina and silica gel using alkali ions or alkaline earth metal ions, and are therefore concerned about reactivity with organometallic compounds. That is, IIA in the organometallic compound,
Since the basic physical properties of the adsorbent used for the MO removal apparatus 8 for recovering the IIB and IIIB elements and the adsorbent used for the apparatus 10 for concentrating the group V-based semiconductor material gas are similar, the results of Example 4 were obtained. IIA, IIB if the metal in the organometallic compound is not removed as inferred from
In addition, it is considered that the group IIIB element is chemically adsorbed to the adsorbent of the apparatus 10 for concentrating the group V-based semiconductor material gas, thereby deteriorating the performance. FIG. 8 shows the result of the investigation. The results of the measurement of the performance of the apparatus 10 for concentrating the group V-based semiconductor material gas with and without the apparatus for recovering the IIA, IIB, and IIIB-based elements in the organometallic compound are shown in the first stage. The gas used for the measurement was II gas and DMZn + III group gas was TMG.
a + TMAl + TMIn contains each concentration 200ppm 1
% PH3 + about 24% hydrogen + 75% nitrogen. The adsorption is performed at 0.5 MPa (the same applies after the absolute pressure), the desorption is performed at room temperature up to the atmospheric pressure, and after the atmospheric pressure is evacuated to 0.05 MPa while increasing the temperature to 70 ° C., the compressor 9
And the container was filled with 0.3 MPa and measured. With the adsorption and desorption steps as one cycle, repeated adsorption and desorption cycles were performed, and the change in the concentration of PH ₃ , a V-group semiconductor material gas, with time was measured. From this result, it became clear that it was necessary to install a device for recovering IIA, IIB, and IIIB-based elements from the organometallic compound in the former stage. Also, V
When activated carbon is selected as the adsorbent of the apparatus 10 for concentrating the group-based semiconductor material gas, desorption requires time, but the concentrated concentration becomes higher, so that activated carbon may be used. The MO removal device 8 for recovering the IIA, IIB, and IIIB-based elements from the organometallic compound may be any stage preceding the device 10 for concentrating the group V-based semiconductor material gas. (Example 6) When the apparatus 8 for recovering the IIA, IIB, and IIIB-based elements in the organometallic compound is installed before the compressor 9, the waste heat of the compressor 9 cannot be used. Using Ni or Al as a catalyst material to promote decomposition of
It is possible to decompose the organometallic compound by heating to about ° C. and recover it with the device 8 for recovering IIA, IIB and IIIB-based elements in the organometallic compound.

FIGS. 9 and 10 show the desorbing effect (concentrating effect) of arsine by introduction of nitrogen. The larger the area of the region with the higher arsine concentration, the more arsine is released.

FIG. 9 is a graph when nitrogen is introduced into the adsorption tower in addition to the operation of TPSA, and FIG. 10 is a case where arsine is desorbed only by the operation of TPSA.

When nitrogen is introduced for the desorption of arsine, nitrogen is not adsorbed in the temperature range of the desorption step, and exerts a physical or concentration-diffusing effect to release a high concentration of arsine.

The nitrogen released with the arsine is then
It is pumped to a cylinder that collects and fills arsine. (Embodiment 7) FIG. 11 shows a cylinder 42.

The gas (90% arsine + 10% nitrogen) obtained from the adsorption tower of the present invention was charged into a cylinder 42 filled with activated carbon 41 at atmospheric pressure or higher. In this case, the amount of nitrogen adsorbed on the activated carbon is extremely small and is released from the outlet 43. 44 is a filter such as a metal mesh. The concentration of arsine filled in the activated carbon was 99% or more. The filter 44 prevents the activated carbon powder from coming out together with the arsine. If the metal mesh is clogged with activated carbon powder, the powder can be removed by blowing high pressure nitrogen through the outlet. The filter seat protects the valve seat.

[0025]

According to the present invention, it is possible to recover a V-group semiconductor special material gas from exhaust gas generated from a semiconductor manufacturing apparatus containing residual arsine which has been conventionally discarded. Can solve all situations.

[Brief description of the drawings]

FIG. 1 is an outline of an exhaust gas treatment system of a chemical liquid treatment and detoxification type.

FIG. 2 is a schematic diagram of an exhaust gas treatment system using a reaction abatement agent.

FIG. 3 is a schematic diagram of a combustion elimination type processing system.

FIG. 4 is a schematic configuration of a compound semiconductor material recovery apparatus.

FIG. 5. IIA, IIB, IIIB in organometallic compounds
For recovering system elements

FIG. 6 is a table showing selective adsorption performance of IIA, IIB, IIIA and group V-based semiconductor material gas in an organometallic compound in an organometallic compound recovery apparatus.

FIG. 7 shows TMGa and AsH _{3 of} an organometallic compound recovery device.
4 is a graph showing an example of the adsorption characteristics.

FIG. 8 is a graph showing the necessity of installing an organometallic compound recovery apparatus in a stage preceding a group V-based semiconductor material gas concentrator.

FIG. 9 is a graph showing the discharge of arsine when nitrogen is introduced into the adsorption tower in addition to the operation of TPSA.

FIG. 10 is a graph showing arsine excretion when only TPSA operation is performed.

FIG. 11 is a schematic configuration diagram of a cylinder for filling and concentrating a group V-based semiconductor material gas.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) B01J 21/02 ZAB B01D 53/36 Z 23/755 B01J 23/74 321A (72) Inventor Masahiro Omoto Osaka Sumitomo Life Shin Osaka Kita Building, 4-1-1-14 Miyahara, Yodogawa-ku, Osaka-shi (72) Inventor Taiji Hashimoto 4-1-1-14 Miyahara, Yodogawa-ku, Osaka-shi, Osaka Sumitomo Life Shin-Osaka Kita Building Osaka Oxygen Industry Co., Ltd. (72) Inventor Takahiko Kurushima 4-1-1, Miyahara, Yodogawa-ku, Osaka City, Osaka Sumitomo Life Shin-Osaka Kita Building Osaka Oxygen Industry Co., Ltd. F-term (reference) 4D002 AA40 AC10 BA04 CA07 DA41 DA45 DA46 DA70 EA07 4D012 CA12 CA20 CB16 CB20 CD03 CD07 CH05 CJ02 4D048 AA17 AB03 BA03X BA38X CD01 4G069 AA08 BC16B BC68B CA02 CA10 CA11 DA05

Claims (12)

[Claims] 1. An apparatus for recovering a group V semiconductor special material gas from an exhaust gas discharged without being consumed in each process relating to the production of a compound semiconductor, the apparatus comprising: IIA contained in the exhaust gas; IIB and / or I
Apparatus for substantially removing Group IIB elements, Apparatus for concentrating Group V semiconductor special material gas from exhaust gas thereof, and Cylinder having a function of further collecting and enriching concentrated Group V semiconductor special material gas And a cylinder cabinet containing the cylinders. 2. The apparatus according to claim 1, wherein the apparatus for concentrating the group V semiconductor special production gas is TPSA. 3. The apparatus according to claim 1, wherein said apparatus for substantially removing a group IIA, IIB and / or IIIB element is an apparatus containing a catalyst. 4. The apparatus according to claim 1, wherein the apparatus for substantially removing the group IIA, IIB and / or IIIB element is an apparatus containing an adsorbent. 5. A method for recovering a group V semiconductor special material gas from an exhaust gas discharged without being consumed in each process related to the production of a compound semiconductor, the method comprising the steps of: IIA contained in the exhaust gas. , IIB and / or
Alternatively, a step (a) of substantially removing a group IIIB element, a step (b) of concentrating a group V semiconductor special material gas from the exhaust gas, and filling and collecting the concentrated group V semiconductor special material gas in a cylinder. A method for recovering a V-group semiconductor special material gas, comprising a step (c) of concentrating. 6. The method according to claim 1, wherein the step (b) is performed with TPSA.
The method of claim 5. 7. The method according to claim 5, wherein step (a) is performed using a catalyst. 8. The method of claim 5, wherein step (a) is performed using an adsorbent. 9. In the step (b), a V-group semiconductor special material gas is adsorbed by a TPSA apparatus, the gas is desorbed by controlling the pressure and temperature, and the gas is further desorbed by using nitrogen. Item 7. The method according to item 5 or 6. 10. Exhaust gas that is not consumed and exhausted in each process related to the production of compound semiconductors.
An adsorption tower for removing a group IB and / or IIIB element, wherein the adsorption tower is filled with molecular sieves, alumina or silica saturated with water. 11. Exhaust gas discharged without being consumed in each process relating to the production of compound semiconductors,
A method for removing a Group IB and / or IIIB element, the method comprising passing the exhaust gas through a layer of silica saturated with water and then passing the exhaust gas through a molecular sieve. 12. A cylinder for recovering a V-group semiconductor material gas from a mixed gas containing nitrogen and the like and a V-group semiconductor material gas separated from exhaust gas discharged without being consumed in each process relating to compound semiconductor production. At
The valve used for the cylinder is provided with an inlet for the mixed gas and an outlet for discharging a gas having low adsorptivity in order to enable the concentration operation. A cylinder which can also be used as a discharge outlet of a system semiconductor material gas and has a filter installed in a passage to the outlet.