Detoxification apparatus, detoxification method and semiconductor manufacturing method

Abstract

To provide a detoxification apparatus which has a high volume reduction effect of a mixed gas to a membrane area of a gas separation membrane, and has high introduction efficiency of the gas separation membrane.SOLUTION: A detoxification apparatus of a mixed gas containing at least one detoxification object gas and a carrier gas includes: a concentration mechanism by a gas separation membrane for concentrating the detoxification object gas in the mixed gas so as to satisfy the following expression 1; and a detoxification mechanism for detoxifying the concentrated detoxification gas. Expression 1: 1.1×Xmixedgas≤Xdetoxificationgas≤0.6×(XMAX-Xmixedgas). In the expression, Xmixedgas represents a volume fraction (vol%) of the detoxification object gas in the mixed gas, the Xdetoxificationgas represents a volume fraction (vol%) of the detoxification object gas in the detoxification gas, and XMAX represents a volume fraction (vol%) of the detoxification object gas in the detoxification gas at a detoxification gas flow rate of 0.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a decontamination device having a concentration mechanism and a decontamination mechanism using a gas separation membrane, a decontamination method, and a semiconductor manufacturing method using the same.

Background Art

[0002] As a method for removing harmful components contained in exhaust gas from manufacturing processes and chemical processes, decontamination devices are known that thermally decompose harmful components into components with lower harmfulness or adsorb and remove harmful components. Examples of harmful components include greenhouse gases, harmful gases, combustible gases, and odor gases. By suppressing the emission amount through thermal decomposition or adsorption and removal by a decontamination device, the environmental load can be reduced.

[0003]

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] ​Patent Document 1 discloses an exhaust gas treatment facility that treats exhaust gas containing one or more fluorine compound gases and one or more carrier gases. The facility includes a membrane separation type concentrator that increases the concentration of the fluorine compound gas in the exhaust gas by membrane-separating and removing the carrier gas in the exhaust gas, and a combustion device that receives the exhaust gas with an increased concentration of the fluorine compound gas by the concentrator and burns and decomposes the fluorine compound gas in the exhaust gas using air. However, in the method described in Patent Document 1, when the fluorine compound gas is concentrated to a high concentration, the amount of exhaust gas before concentration that can be treated per unit membrane area decreases, resulting in a large required membrane area for the concentrator and the problem of the device becoming large.

[0006] Therefore, an object of the present invention is to provide a decontamination device having a large mixed gas volume reduction effect per unit membrane area of a gas separation membrane and a high introduction efficiency of the gas separation membrane.

Means for Solving the Problems

[0007] To solve the above problems, the present invention has the following configuration. That is, the present invention is a decontamination device for a mixed gas containing at least one decontamination target gas and a carrier gas, and includes a concentration mechanism by a gas separation membrane that concentrates the volume fraction of the decontamination target gas in the mixed gas until it satisfies the following formula 1, and a decontamination mechanism that decontaminates the concentrated decontamination gas.

[0008] 1.1×X 混合ガス ≦ X 除害ガス ≦ 0.6×(X MAX ―X 混合ガス ) ··· Formula 1 [In the formula, X 混合ガス represents the volume fraction (vol%) of the decontamination target gas in the mixed gas, X 除害ガス represents the volume fraction (vol%) of the decontamination target gas in the decontamination gas, and X MAX represents the volume fraction (vol%) of the decontamination target gas in the decontamination gas at a decontamination gas flow rate of 0.]

Effects of the Invention

[0009] The pest control device of the present invention can increase the volume of the mixed gas that can be processed per unit membrane area of the gas separation membrane by using the gas separation membrane in the concentration range where the pest control target gas is likely to be concentrated. Therefore, it is possible to pest control the pest control target gas in an energy-saving manner while suppressing the introduction amount of the gas separation membrane.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] The present invention will be described below with reference to the drawings by way of examples. However, the present invention should not be construed as being limited to the examples.

[0012] The pest control device of the present invention is a pest control device for a mixed gas containing at least one pest control target gas and a carrier gas, and has a concentration mechanism by a gas separation membrane for concentrating the volume fraction of the pest control target gas in the mixed gas until it satisfies the following formula 1, and a pest control mechanism for pest controlling the concentrated pest control gas.

[0013] 1.1×X 混合ガス ≦ X 除害ガス ≦ 0.6×(X MAX ―X 混合ガス ) ··· Formula 1 [In the formula, X 混合ガス represents the volume fraction (vol%) of the pest control target gas in the mixed gas, X 除害ガス represents the volume fraction (vol%) of the pest control target gas in the pest control gas, and X MAX represents the volume fraction (vol%) of the pest control target gas in the pest control gas when the pest control gas flow rate is 0.] As described above, in the prior art, when attempting to concentrate a target gas to be removed in a mixed gas near the upper limit of the concentration ability of the gas separation membrane to obtain a gas to be removed, as the volume fraction of the target gas to be removed in the gas to be removed increases, the concentration of the target gas to be removed becomes difficult to progress. Therefore, the volume of the mixed gas that can be processed per membrane area becomes small, and there is a problem that the required membrane area of the gas separation membrane increases to ensure the throughput, resulting in the enlargement of the device. By using the gas removal device of the present invention, since the gas separation membrane is used in a concentration range in which the target gas to be removed is easily concentrated, the volume of the mixed gas that can be processed per membrane area of the gas separation membrane can be increased. Therefore, it is possible to remove the target gas to be removed while suppressing the introduction amount of the gas separation membrane.

[0014] FIG. 1 shows, as one aspect of the present invention, a gas removal device having a concentration mechanism and a gas removal mechanism including a gas separation membrane and a flow rate control unit. A mixed gas (path 11) containing at least one type of target gas to be removed and a carrier gas is supplied to the concentration mechanism 2 and separated into a permeated gas (path 12) in which the carrier gas is concentrated and a gas to be removed (path 13) in which the target gas to be removed is concentrated. In the concentration mechanism 2, the target gas to be removed is concentrated by preferentially permeating the carrier gas in the mixed gas through the gas separation membrane 4. There is a flow rate control unit 5 in at least one of the upstream (path 11) on the non-permeating side of the gas separation membrane 4, the downstream (path 12) on the permeating side, and the downstream (path 13) on the non-permeating side, and the volume fraction of the target gas to be removed in the gas to be removed is controlled by controlling the flow rate of the gas passing through paths 11 to 13. The gas to be removed is supplied to the gas removal mechanism 3 and becomes an exhaust gas (path 14) downstream of the gas removal mechanism in which at least a part of the target gas to be removed has been removed, and is directly exhausted, or exhausted or recovered through an additional purification process. At least a part of the permeated gas (path 12) may be reused and supplied as a carrier gas.

[0015] The mixed gas represents a gas containing at least one type of target gas to be removed and a carrier gas. Here, the target gas to be removed represents a gas that is preferably not released into the atmosphere due to its impact on the environment and the human body, and the carrier gas represents a gas other than the target gas to be removed.

[0016] Examples of the gas to be removed include boron compound gas, fluorine compound gas, silicon compound gas, chlorine compound gas, HCN, and the like.

[0017] Examples of the boron compound gas include B2H6, BF3, BCl3, etc. Examples of the fluorine compound include hydrofluorocarbons (hereinafter referred to as "HFCs"), perfluorocarbons (hereinafter referred to as "PFCs"), SF6, NF3, BF3, SiF4, etc. Examples of PFCs include perfluorocarbon, perfluoroalkylsulfonic acid, perfluoroalkylcarboxylic acid, etc. Examples of the silicon compound gas include SiH4, SiH2Cl2, Si2H6, SiCl4, SiF4, (C2H5O)4Si, etc. Examples of the chlorine compound gas include HCl, Cl2, SiH2Cl2, SiCl4, etc.

[0018] Since the global warming potential is high, it is preferable to remove the mixed gas containing HFCs, PFCs, SF6, and NF3 with the pest control system of the present invention, and by doing so, the environmental load can be greatly reduced.

[0019] The mixed gas of the present invention preferably contains the gas to be removed at 1 ppm or more and 10,000 ppm or less. When the mixed gas contains the gas to be removed at 1 ppm or more, the effect of reducing the environmental load by pest control becomes greater. The gas to be removed contained in the mixed gas is preferably 10 ppm or more, more preferably 100 ppm or more. On the other hand, when the gas to be removed contained in the mixed gas is 10,000 ppm or less, the energy-saving effect of the pest control device when concentrating the gas to be removed is improved. The gas to be removed contained in the mixed gas is preferably 5,000 ppm or less, more preferably 2,000 ppm or less. The volume fraction of the gas to be removed in the mixed gas represents the total value of the volume fractions of all the gases to be removed contained in the mixed gas.

[0020] The carrier gas of the present invention preferably contains at least one selected from the group consisting of H2, He, H2O, CO2, N2, and Ar. Since H2, He, H2O, CO2, N2, and Ar have high permeability through the gas separation membrane with respect to the gas to be removed, it is possible to concentrate the gas to be removed even with a small membrane area of the gas separation membrane. Since the permeability of the gas separation membrane is particularly high, it is more preferable that the carrier gas contains at least one selected from the group consisting of He, H2O, and CO2.

[0021] The concentration mechanism of the present invention is a concentration mechanism that concentrates the gas to be removed in the mixed gas with a gas separation membrane.

[0022] The gas separation membrane is a membrane with different permeabilities for the gas to be removed and the carrier gas. When a mixed gas is supplied to a gas separation membrane in which the carrier gas has high permeability with respect to the gas to be removed, the carrier gas preferentially permeates through the gas separation membrane, and the gas to be removed is concentrated on the non-permeable side of the gas separation membrane.

[0023] The gas separation membrane of the present invention preferably has an ideal separation factor of 100 or more and 10,000 or less. When the ideal separation factor of the gas separation membrane is 100 or more, it is possible to concentrate to a higher concentration even if the volume fraction of the gas to be removed in the mixed gas is low. More preferably, the ideal separation factor of the gas separation membrane is 200 or more, and even more preferably 500 or more. On the other hand, when the ideal separation factor of the gas separation membrane is 10,000 or less, the permeability of the carrier gas through the gas separation membrane is improved, and the required membrane area can be reduced. More preferably, the ideal separation factor of the gas separation membrane is 5,000 or less, and even more preferably 2,000 or less.

[0024] Note that the ideal separation factor referred to in the present invention represents the permeability of the carrier gas single gas with respect to the permeability of the gas to be removed single gas (that is, "permeability of the carrier gas single gas / permeability of the gas to be removed single gas"), and when there are a plurality of carrier gases and gases to be removed, it represents the ideal separation factor of the carrier gas and the gas to be removed having the largest volume fraction in the mixed gas. The permeability of the single gas can be measured by the differential pressure method described in JIS K 7126-1 (2006).

[0025] Examples of the gas separation membrane include inorganic membranes such as zeolite membranes, metal-organic framework (MOF) membranes, and carbon membranes, and polymer membranes. It is preferable to use an inorganic membrane because of its high chemical stability and ease of increasing the ideal separation factor.

[0026] A zeolite membrane is a gas separation membrane having a separation functional layer made of zeolite. Examples of the zeolite membrane include membranes made of aluminosilicates such as NaX type (FAU), ZSM-5, MOR, silicalite, or type A. It is more preferable to be a medium-pore zeolite having a 10-membered ring because it has a pore diameter between the size of the carrier gas and the size of the gas to be removed. Examples of the medium-pore zeolite having a 10-membered ring include ZSM-5. Two or more of these may be used.

[0027] An MOF membrane is a gas separation membrane having a separation functional layer made of MOF. Examples of the MOF membrane include membranes made of, for example, Cu-BTC, MOF-5, IRMOF-3, MIL-47, MIL-53, MIL-96, MMOF, SIM-1, ZIF-7, ZIF-8, ZIF-22, ZIF-69, ZIF-90, etc. Two or more of these may be used.

[0028] A carbon membrane is a gas separation membrane having a separation functional layer made of carbon. Examples of the carbon membrane include membranes obtained by carbonizing, for example, polyphenylene oxide, polyvinyl alcohol, polyacrylonitrile, phenol resin, wholly aromatic polyester, unsaturated polyester resin, alkyd resin, melamine resin, urea resin, polyimide resin, diallyl phthalate resin, lignin resin, urethane resin, etc. Two or more of these may be used.

[0029] The polymer membrane is a gas separation membrane having a separation functional layer made of a polymer. Examples of the polymer membrane include membranes made of aromatic polyimide, cellulose acetate, polysulfone, aromatic polyamide, polyetherimide, polyethersulfone, polyacrylonitrile, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyvinylidene fluoride, poly(1-trimethylsilylpropyne), polydimethylsiloxane, polyvinyltrimethylsilane, poly(4-methylpentene), ethyl cellulose, natural rubber, poly(2,6-dimethylphenylene oxide), low-density polyethylene, high-density polyethylene, styrene, polyethyl methacrylate, polycarbonate, polyester, aliphatic polyamide, polymethyl methacrylate, polyvinyl alcohol, silicone, etc. Two or more of these may be used.

[0030] Examples of the shape of the gas separation membrane include a flat membrane, a hollow fiber membrane, and a solid fiber membrane. The gas separation membrane is preferably used as a gas separation membrane module (hereinafter sometimes simply referred to as "module") in which the housing is filled with the gas separation membrane. When the gas separation membrane is made into a module, since it is easy to increase the membrane area per unit volume of the module, the gas separation membrane is preferably a hollow fiber membrane or a solid fiber membrane, and more preferably a hollow fiber membrane because the fluid permeability can be improved. The outer diameter of the gas separation membrane which is a hollow fiber membrane or a solid fiber membrane is preferably 50 μm or more and 2,000 μm or less. By setting the outer diameter of the gas separation membrane to 50 μm or more, the fluid permeability can be improved. The outer diameter of the gas separation membrane is more preferably 100 μm or more, and even more preferably 200 μm or more. On the other hand, by setting the outer diameter of the gas separation membrane to 2,000 μm or less, the membrane area of the gas separation membrane per unit volume in the case of a gas separation membrane module can be increased. The outer diameter of the gas separation membrane is more preferably 1,000 μm or less, and even more preferably 500 μm or less.

[0031] The pest control device of the present invention preferably includes a plurality of gas separation membrane modules according to the composition and throughput of the mixed gas. The plurality of modules may be connected in series or in parallel.

[0032] The concentration mechanism of the present invention is characterized in that it concentrates the volume fraction of the gas to be removed in the mixed gas until it satisfies the following formula (1). X 除害ガス is X 混合ガス 1.1 times or more, the gas to be removed in the pest control gas is concentrated, and the energy consumption in the pest control mechanism can be suppressed. X 除害ガス is X 混合ガス 1.2 times or more is more preferable, and 1.5 times or more is even more preferable. On the other hand, X 除害ガス is X MAX -X 混合ガス 0.6 times or less, the gas separation membrane is used in a concentration range where the gas to be removed is easily concentrated, and the volume of the mixed gas that can be processed per unit membrane area of the gas separation membrane can be increased. X 除害ガス is X MAX -X 混合ガス 0.4 times or less is more preferable, and 0.15 times or less is even more preferable.

[0033] 1.1×X 混合ガス ≦ X 除害ガス ≦ 0.6×(X MAX -X 混合ガス ) ··· Formula (1) [In the formula, X 混合ガス represents the volume fraction (vol%) of the gas to be removed in the mixed gas, X 除害ガス represents the volume fraction (vol%) of the gas to be removed in the pest control gas, X MAX represents the volume fraction (vol%) of the gas to be removed in the pest control gas at a pest control gas flow rate of 0.] X MAX is the volume fraction of the gas to be removed in the pest control gas when only the flow rate of the pest control gas is changed to 0 from the normal operating state of the pest control device, and represents the volume fraction of the gas to be removed in the pest control gas flowing in a very small amount after waiting until the non-permeate side outlet composition of the fluid separation membrane reaches a steady state after closing the path of the pest control gas. X MAXrepresents the maximum value of the volume fraction of the gas to be removed in the pest control gas that can be concentrated under specific pest control devices and operating conditions, and it varies depending on the membrane performance and membrane area of the fluid separation membrane, the composition of the supplied mixed gas, and the permeate-side pressure and non-permeate-side pressure of the fluid separation membrane.

[0034] X 混合ガス is the mixed gas, X 除害ガス and X MAX can be obtained by gas chromatography analysis of the pest control gas, and when the mixed gas or the pest control gas contains a plurality of gases to be removed, it is represented by the total value of them. Also, X 除害ガス and X MAX as, instead of immediately after the start of operation or immediately after a change in operating conditions, the value in the steady state after operating for a certain period of time under specific operating conditions is used. The steady state means that 除害ガス and X MAX the change over time of is small, and when the change in the volume fraction (vol%) of the gas to be removed measured at one-hour intervals is within 5%, it can be regarded as the steady state.

[0035] The pest control device of the present invention preferably has a flow rate control unit in at least one of the path of the mixed gas, the path of the permeated gas, or the path of the pest control gas. By doing so, it becomes easy to adjust the flow rate balance of the mixed gas, the permeated gas, and the pest control gas, and it becomes easy to control the volume fraction of the gas to be removed in the pest control gas.

[0036] Examples of the flow rate control unit include flow rate control devices such as mass flow controllers and blowers, and pumps and pressure control devices for controlling the differential pressure between the permeate side and the non-permeate side of the gas separation membrane.

[0037] The pest control mechanism is a mechanism for detoxifying the gas to be removed contained in the pest control gas. Here, the pest control gas represents the gas in which the gas to be removed is concentrated from the mixed gas by the gas separation membrane.

[0038] Examples of the pest control mechanism include a thermal decomposition type pest control device, a combustion type pest control device, a dry type pest control device, a wet type pest control device, a catalytic type pest control device, a plasma type pest control device, etc. Two or more of these may be combined.

[0039] The mixed gas to be detoxified by the detoxification device of the present invention is not particularly limited. For example, it can be suitably used for detoxifying exhaust gas generated in chemical processes or semiconductor manufacturing processes.

[0040] The detoxification method of the present invention is a method for detoxifying a mixed gas containing at least one gas to be detoxified and a carrier gas, comprising a step of concentrating the volume fraction of the gas to be detoxified in the mixed gas with a fluid separation membrane until it satisfies the following formula (1), and a step of supplying the detoxifying gas to a detoxification mechanism to detoxify the gas to be detoxified.

[0041] 1.1×X 混合ガス ≦ X 除害ガス ≦ 0.6×(X MAX ―X 混合ガス ) ··· Formula (1) [In the formula, X 混合ガス represents the volume fraction (vol%) of the gas to be detoxified in the mixed gas, X 除害ガス represents the volume fraction (vol%) of the gas to be detoxified in the detoxifying gas, and X MAX represents the volume fraction of the gas to be detoxified at a detoxifying gas flow rate of 0.] By doing so, since the gas separation membrane is used in a concentration range where the gas to be detoxified is easily concentrated, the volume of the mixed gas that can be processed per membrane area of the gas separation membrane can be increased. Therefore, the gas to be detoxified can be detoxified while suppressing the introduction amount of the gas separation membrane.

[0042] The semiconductor manufacturing method of the present invention is a semiconductor manufacturing method including the detoxification method of the present invention. That is, it is a semiconductor manufacturing method including a step of detoxifying a gas containing a gas to be detoxified discharged in a semiconductor manufacturing process by the detoxification method of the present invention. Examples of the semiconductor manufacturing process include CVD, etching, chamber cleaning, etc., and it may include a plurality of semiconductor manufacturing processes.

[0043] The mixed gas to be detoxified by the semiconductor manufacturing method of the present invention is not particularly limited, but examples of the gas to be detoxified include fluorine compound gas and the like. Since the semiconductor manufacturing method of the present invention can detoxify the gas to be detoxified while suppressing the required membrane area of the gas separation membrane, it is possible to manufacture a compact semiconductor with reduced environmental load.

Example

[0044] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto. The evaluations in each example and comparative example were conducted by the following methods.

[0045] (Amount of gas to be detoxified that can be treated per unit membrane area) By adjusting the flow rate of the detoxifying gas in the detoxifying device of the example, X 除害ガス / (X MAX ―X 混合ガス ) was changed stepwise from 0.086 to 1.07. At each evaluation point, the flow rate of the detoxifying gas and the volume fraction of the gas to be detoxified in the detoxifying gas were integrated to obtain the amount of the gas to be detoxified in the detoxifying gas.

[0046] (Volume reduction effect of detoxifying gas) By adjusting the flow rate of the detoxifying gas in the detoxifying device of the example, X 除害ガス / (X MAX ―X 混合ガス ) was changed stepwise from 0.086 to 1.07. At each evaluation point, 1-X 混合ガス / X 除害ガス was calculated and expressed as a percentage to obtain the volume reduction effect of the detoxifying gas.

[0047] (Production Example 1: Preparation of gas separation membrane module) 10 parts by weight of polyacrylonitrile (weight average molecular weight 150,000) manufactured by Poly Science, 10 parts by weight of polyvinylpyrrolidone (weight average molecular weight 40,000) manufactured by Sigma-Aldrich, and 80 parts by weight of dimethyl sulfoxide (hereinafter, DMSO) manufactured by Fujifilm Wako Pure Chemical were mixed and stirred at 100 ° C to prepare a spinning dope.

[0048] After cooling the obtained spinning dope to 25°C, using a die of a concentric triple orifice, an 80 wt% aqueous solution of DMSO was simultaneously discharged from the inner tube, the spinning dope was discharged from the middle tube, and a 90 wt% aqueous solution of DMSO was discharged from the outer tube. Then, it was led into a coagulation bath composed of pure water at 25°C and wound around a roller to obtain a raw yarn. After washing the obtained raw yarn with water, it was dried at 25°C for 24 hours using a circulation dryer to produce a precursor of a hollow fiber membrane-like porous carbon membrane.

[0049] The obtained precursor of the porous carbon membrane was passed through an electric furnace at 250°C and heated in an air atmosphere for 1 hour for non-melting treatment to obtain a non-melting yarn. Subsequently, the non-melting yarn was carbonized at a carbonization temperature of 650°C to obtain a carbon membrane with an outer diameter of 300 μm and an inner diameter of 100 μm. The ideal separation factor of N2 and SF6 of the carbon membrane measured according to the differential pressure method of JIS K 7126-1(2006) was 550.

[0050] Three hundred of the obtained carbon membranes were bundled and housed in an acrylic pipe (inner diameter 8 mm) having an inlet and an outlet for the fluid to be separated. Both ends of the acrylic pipe were static potted one by one using an epoxy resin. After the epoxy resin hardened, the potted part at one end was cut with a rotary saw to open the gas separation membrane, and the gas separation membrane module of Production Example 1 was obtained.

[0051] (Example 1) The permeate side of the gas separation membrane module of Production Example 1 was connected to an oil rotary vacuum pump GLD-137CC (manufactured by Alvac) via a throttle valve. A throttle valve was arranged on the upstream side of the non-permeate side, and the downstream side of the non-permeate side was connected to a decontamination device MODEL-WGT (manufactured by Nippon Pionics) via a flow meter ALTImassII TypeU (manufactured by Oval). The pipe between the gas separation membrane module and the decontamination device was heat-insulated, and a decontamination device having the form of FIG. 1 capable of supplying a mixed gas of SF6 and N2 (SF6: 0.1%, N2: 99.9%) from the supply side of the gas separation membrane module was produced. The results evaluated by the above method are shown in FIG. 2. FIG. 2 is X 除害ガス / (X MAX -X 混合ガスIt is a graph showing the correlation between the volume reduction effect on and the amount of decontaminated gas. The introduction effect of the gas separation membrane is preferably high when the decrease in the amount of decontaminated gas is small with respect to the increase in the volume reduction effect. X 除害ガス / (X MAX -X 混合ガス ) In the region where it is 0.6 or less, the inequality on the right side of Equation 1 is satisfied, and the decrease in the amount of decontaminated gas is small with respect to the increase in the volume reduction effect. On the other hand, in the region where the inequality on the left side of Equation 1 (not shown) is satisfied, the target gas to be decontaminated in the decontaminated gas is concentrated, so the energy consumption in the decontamination mechanism can be suppressed.

Industrial Applicability

[0052] The decontamination system of the present invention can be suitably used for decontaminating exhaust gas generated in a chemical process.

Explanation of Signs

[0053] 1: Decontamination device 2: Concentration mechanism 3: Decontamination mechanism 4: Gas separation membrane 5: Flow control unit 11: Path (mixed gas) 12: Path (permeated gas) 13: Path (decontaminated gas) 14: Path (gas after decontamination)

Claims

1. A pest control device for a mixed gas containing at least one gas to be exterminated and a carrier gas, a concentration mechanism by a gas separation membrane that concentrates the volume fraction of the gas to be exterminated in the mixed gas until it satisfies the following formula 1, and a pest control device having a pest control mechanism for exterminating the concentrated pest gas. 1.1 × X 混合ガス ≤ X 除害ガス ≤ 0.6 × (X ＭＡＸ − X 混合ガス )... Equation 1 [In the formula, X 混合ガス represents the volume fraction (vol%) of the gas to be removed in the mixed gas, and X 除害ガス represents the volume fraction (vol%) of the gas to be removed in the removal gas, and X ＭＡＸ represents the volume fraction (vol%) of the gas to be removed in the removal gas when the flow rate of the removal gas is 0.]

2. The pest control device according to claim 1, wherein the concentration mechanism has a flow rate control unit in at least one of the path of the mixed gas, the path of the permeated gas, and the path of the pest gas.

3. The pest control device according to claim 1, wherein the ideal separation factor of the gas separation membrane is 100 or more and 10,000 or less.

4. The pest control device according to claim 3, wherein the gas separation membrane is an inorganic membrane.

5. The pest control device according to any one of claims 1 to 4, wherein the mixed gas contains 1 ppm or more and 10,000 ppm or less of the gas to be exterminated.

6. The pest control device according to claim 5, wherein the gas to be exterminated contains at least one selected from the group consisting of boron compound gas, fluorine compound gas, silicon compound gas, chlorine compound gas, and HCN.

7. A pest control method for a mixed gas containing at least one gas to be exterminated and a carrier gas, a step of concentrating the volume fraction of the gas to be exterminated in the mixed gas with a gas separation membrane until it satisfies the following formula 1, and a step of supplying the pest gas to a pest control mechanism to exterminate the gas to be exterminated. 1.1 × X 混合ガス ≤ X 除害ガス ≤ 0.6 × (X ＭＡＸ − X 混合ガス )... Equation 1 [In the formula, X 混合ガス represents the volume fraction (vol%) of the gas to be removed in the mixed gas, and X 除害ガス represents the volume fraction (vol%) of the gas to be removed in the removal gas, and X ＭＡＸ represents the volume fraction of the gas to be removed at a removal gas flow rate of 0.]

8. A semiconductor manufacturing method including the pest control method according to claim 7.

Images