Processing method

Abstract

To provide a processing method that can safely process a mixture containing one or both of halosilanes and hydrolysates of halosilanes.SOLUTION: A processing method for processing a mixture containing one or both of halosilanes and hydrolysates of halosilanes includes a step of bringing a process liquid having a pH of 8 or more and 14 or less and a mass equivalent to 100 times or more based on the mass of the mixture into contact with the mixture.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Embodiments of the present invention relate to processing methods. [Background technology]

[0002] Semiconductor silicon substrates are widely used as materials for forming various electronic circuits. When forming these semiconductor silicon substrates, and when forming films or ingots containing silicon, silicon-containing material formation equipment such as epitaxial growth systems and chemical vapor deposition systems are used.

[0003] The epitaxial growth apparatus comprises a reaction chamber, a supply pipe, and an exhaust pipe connected to the reaction chamber. A raw material gas is supplied to the reaction chamber via the supply pipe. Exhaust gas is then discharged from the reaction chamber via the exhaust pipe. When using the epitaxial growth apparatus, a substrate is placed in the reaction chamber under reduced pressure and an inert atmosphere. A silicon-containing film is formed on the substrate by reacting the raw material gas introduced into the reaction chamber with the heated substrate. For example, a mixed gas of a compound containing silicon and chlorine, and hydrogen gas is used as the raw material gas. The raw material gas that has reacted with the substrate in the reaction chamber is discharged as exhaust gas to the outside of the apparatus via the exhaust pipe. The exhaust gas may contain components of the raw material gas, such as a compound containing silicon and chlorine, and hydrogen gas.

[0004] Here, the temperature inside the reaction chamber is significantly higher than that inside the exhaust pipe. Therefore, silicon and chlorine-containing compounds in the exhaust gas discharged into the exhaust pipe are cooled inside the pipe and may precipitate as by-products. These by-products may include highly viscous liquid and solid substances, also known as oily silanes. Furthermore, the by-products may include substances secondarily produced when oily silanes are altered in air or water. It is necessary to safely neutralize these by-products. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 1-257119 [Patent Document 2] Japanese Patent Application Publication No. 4-124011 [Patent Document 3] WO2019 / 181044 publication [Patent Document 4] WO2019 / 181045 publication [Patent Document 5] WO2020 / 153385 publication [Non-patent literature]

[0006] [Non-Patent Document 1] Frank Meyer-Wegner, Andor Nadj, Michael Bolte, Norbert Auner, Matthias Wagner, Max C. Holthausen, and Hans-Wolfram W. Lerner, “The Perchlorinated Silanes Si2Cl6 and Si3Cl8 as Sources of SiCl2” Chemistry A European Journal, April 18, 2011, Volume 17, Issue 17, p. 4715-4719. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The objective of the embodiment is to provide a processing method that can safely process a mixture containing one or both halosilanes and hydrolysates of halosilanes. [Means for solving the problem]

[0008] According to an embodiment, there is provided a treatment method for treating a member in which a mixture containing one or both of halosilanes and hydrolysis products of halosilanes is contained or adhered. A treatment liquid having a pH of 8 or more and 14 or less and having a mass corresponding to 100 times or more the mass of the mixture is brought into contact with the member, and the amount of temperature change of the treatment liquid during the treatment is controlled to 10°C or less. The treatment solution is a basic aqueous solution containing at least one of an inorganic base or an organic base. The inorganic base is at least one selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, magnesium hydroxide, ammonium hydroxide, copper hydroxide, iron hydroxide, zinc hydroxide, aluminum hydroxide, elemental potassium, elemental lithium, elemental sodium, sodium carbonate, potassium carbonate, ammonium carbonate, lithium carbonate, barium carbonate, magnesium carbonate, sodium bicarbonate, ammonium bicarbonate, potassium bicarbonate, calcium bicarbonate, calcium oxide, magnesium oxide, and sodium oxide. The organic base is at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline hydroxide, butyllithium, methyllithium, butylmagnesium, methylmagnesium, sodium ethoxide, sodium butoxide, potassium ethoxide, potassium butoxide, sodium phenoxide, lithium phenoxide, methylamine, dimethylamine, trimethylamine, triethylamine, ethylenediamine, diethylamine, aniline, pyridine, pyrrolidine, imidazole, and piperidine.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of an epitaxial growth apparatus as an apparatus in which a by-product to be treated is generated. [Figure 2] FIG. 2 is a schematic diagram showing a treatment apparatus used in the method according to the embodiment. [Figure 3] It is a block diagram regarding temperature control in the treatment apparatus shown in FIG. 2. [Figure 4] Flow chart showing the first example of the treatment method of the embodiment. [Figure 5] Flow chart showing the second example of the treatment method of the embodiment. [Figure 6] Flow chart showing the third example of the treatment method of the embodiment. [Figure 7] Flow chart showing the fourth example of the treatment method of the embodiment. [Figure 8] Flow chart showing the fifth example of the treatment method of the embodiment.

Mode for Carrying Out the Invention

[0010] First, halosilanes to be treated will be described. Halosilanes include, for example, halosilanes having a chain structure and halosilanes having a cyclic structure. Halosilanes having a cyclic structure may be represented by any of the following structural formulas (a) to (d). In structural formulas (a) to (d), X is at least one halogen element selected from the group consisting of F, Cl, Br, and I.

[0011]

Chemical formula

[0012] [ka]

[0013] [ka]

[0014] [ka]

[0015] (d) shows an example in which a silyl group is bonded to the Si atoms at positions 1 and 2 of the 6-membered ring structure, but it is not limited to this. For example, there are cases in which a silyl group is bonded to the Si atoms at positions 1 and 3 of the 6-membered ring structure, or to the Si atoms at positions 1 and 4 of the 6-membered ring structure.

[0016] Here, halosilanes having a cyclic structure may have a 4-membered ring structure, a 5-membered ring structure, a 6-membered ring structure other than those in structural formulas (a) to (d), a 7-membered ring structure, an 8-membered ring structure, a multi-membered ring structure, etc., as shown in structural formulas (1) to (21) below. In structural formulas (1) to (21) below, X is at least one halogen element selected from the group consisting of F, Cl, Br, and I. Structural formulas (1-1) to (21-1) below represent chlorosilanes in which element X in structural formulas (1) to (21) is chlorine, respectively.

[0017] The cyclic halosilanes applicable to the processing method of the embodiment are not limited to those shown in structural formulas (a) to (d), structural formulas (1) to (21), and structural formulas (1-1) to (21-1). The processing method of the embodiment can also be applied to isomers (structural isomers) of the compounds shown in these structural formulas. For example, the position of the silyl group in a five-membered ring compound is not limited to the Si atoms at positions 1 and 2 as exemplified in structural formula (3), but may also be the Si atoms at positions 1 and 3, etc.

[0018] [ka]

[0019] [ka]

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] The cyclic halosilanes contained in the mixture may be monocyclic compounds having a silicon ring composed solely of silicon, as shown in structural formulas (1) to (21) above. Alternatively, they may be inorganic cyclic compounds that do not contain carbon, as shown in structural formulas (1) to (21) above. The mixture may also contain heterocyclic compounds composed of silicon and oxygen.

[0025] Halosilanes with the cyclic structure shown in the above structural formula are thermodynamically stable. However, these cyclic halosilanes possess Si-Si bonds and Si-X bonds (where X is at least one halogen element selected from the group consisting of F, Cl, Br, and I). These bonds exhibit high reactivity with water. Therefore, cyclic halosilanes are thought to react rapidly with water in the atmosphere. Such halosilanes are thought to further react with water to produce explosive substances. These explosive substances are thought to be, for example, silyl ethers, siloxanes, silanols, or mixtures thereof.

[0026] Halosilanes having a chain-like structure are represented, for example, by the following structural formulas (22) and (23). In structural formula (22), N is, for example, an integer between 0 and 15. In structural formulas (22) and (23), X is at least one halogen element selected from the group consisting of F, Cl, Br, and I. Structural formulas (22-1) and (23-1) below represent chlorosilanes in which element X in structural formulas (22) and (23) is chlorine, respectively.

[0027] [ka]

[0028] Halosilanes having a chain-like structure may be straight-chain compounds without branching, as shown in structural formula (22) above. Alternatively, halosilanes having a chain-like structure may be branched-chain compounds, as shown in structural formula (23). The presence of halosilanes having a chain-like structure in a mixture can be estimated by mass spectrometry.

[0029] The presence of cyclic chlorosilanes in the mixture can be estimated by the following method.

[0030] First, the silicon-containing material formation apparatus is dismantled, and the piping to which the by-products have adhered is removed. For example, a curved pipe located downstream of the pressure regulating valve 17 in the exhaust gas flow path, such as pipe 14 shown in Figure 1 (described later), is removed. Next, both ends of the removed pipe are plugged. This work is carried out under an inert atmosphere such as nitrogen (N2) gas.

[0031] Next, the removed piping is moved into a glove box purged with an inert gas such as nitrogen gas. Then, by-products are collected from the piping and analytical samples are prepared for use in nuclear magnetic resonance (NMR) spectroscopy and mass (MS) analysis. The atmosphere inside the glove box is preferably an argon atmosphere with a moisture concentration of 1 ppm or less and an oxygen concentration of 10 ppm or less. As a glove box, for example, a VAC101965OMNI-LAB STCH-A manufactured by VAC Corporation is used. When transporting each analytical sample to its respective analytical instrument, it is placed in a resin container, and then this resin container is placed in a sealed container before being moved from the glove box to the respective analytical instrument. When preparing each analytical sample, care should be taken to prevent contact between the analytical sample and oxygen and water. When it is unavoidable to expose each analytical sample to air, such as when setting the analytical sample in the analytical instrument, this should be done quickly.

[0032] Next, the by-products are analyzed by nuclear magnetic resonance (NMR) spectroscopy. For the analysis sample, for example, 0.2 g of the by-product is mixed with 2 mL of dehydrated heavy toluene (manufactured by Kanto Chemical Co., Ltd.: product number 21744-1A), and this mixture is allowed to stand for 4 hours. Then, this mixture is transferred to a sample tube with a J.YOUNG valve (S-5-600-JY-8) manufactured by Haruna Co., Ltd. Next, this NMR sample tube is placed in the NMR spectrophotometer. 29 The Si NMR spectrum is measured. As an NMR spectrophotometer, for example, the JNM-ECA800 manufactured by JEOL Ltd. can be used. 29 For measuring Si NMR spectra, for example, the number of integration cycles is set to 3500, and the measurement range is set to between -500 ppm and 500 ppm.

[0033] Next, the by-products are analyzed by mass (MS) spectrometry to obtain mass spectra. For the analytical sample, for example, a solution of the by-products dissolved in degassed and dehydrated toluene is used. The concentration of the by-products in this solution is 5% by mass, and the water content is 0.6 ppm or less. For the degassing and dehydration of toluene, for example, a VAC SOLVENT PURIFIER 103991 manufactured by VAC is used. For the mass spectrometer, for example, a Bruker Daltonics solariX 9.4T is used. The ionization method used is APCI (Atmospheric Pressure Chemical Ionization). For the measurement of the mass spectrum, for example, the number of integration cycles is set to 300, and the measurement range is set to between 100 m / z and 2000 m / z.

[0034] Based on these analysis results, it can be inferred that the mixture contains halosilanes having a cyclic structure when the following requirements (1) and (2) are met simultaneously.

[0035] Requirement (1): 29 In the Si NMR spectrum, the signal with the highest relative intensity appears at -0.4 ppm. Based on the data described in Non-Patent Document 1, it is estimated that the signal appearing at -0.4 ppm belongs to either a SiCl3 unit or a SiCl2 unit.

[0036] Requirement (2): In the mass spectrum, (SiCl2) n Signals containing this can be detected in the range of mass-to-charge ratio from 0 m / z to approximately 1500 m / z. For example, (SiCl2) n A signal attributable to this is detected within the range of 391 m / z to 1545 m / z.

[0037] That is, from the requirement of (1), it is considered that the mixture mainly contains a substance whose molecular skeleton is composed of SiCl2 units and SiCl3 units. Also, from the requirement of (2), it is considered that the mixture contains a substance with a mass ratio of silicon to chlorine of 1:2. The compositional formula of such a substance is (SiCl2) n is considered, and n is considered to be 3 or more and 15 or less. (SiCl2) n is, for example, Si6Cl 12 Si 14 Cl 28 and Si 15 Cl 30 represented by. As compounds having such a mass ratio, those having a Si=Si bond and those having a cyclic structure are considered. However, since the Si=Si bond is a very unstable bond and decomposes immediately at room temperature, it is considered that the substance having this mass ratio does not have a Si=Si bond. Therefore, it is considered that the substance having this mass ratio has a cyclic structure.

[0038] The hydrolysis product can be obtained, for example, by bringing water into contact with halosilanes. The hydrolysis product can be solid. The hydrolysis product may be in a lump form or in a fine particle form.

[0039] The hydrolysis product may contain a compound having at least one of a siloxane bond (Si-O-Si) and a silanol group (-Si-OH). Also, the hydrolysis product may contain a hydrosilanol group (-Si(H)OH). The fact that the hydrolysis product has at least one of a siloxane bond and a silanol group can be estimated by nuclear magnetic resonance spectroscopy described below.

[0040] First, the by-product is collected using the same method as described above. In a fume hood in the open air, pure water is added to a petri dish containing the by-product to obtain a mixture of the by-product and pure water. The amount of pure water is, for example, 1 mL for 50 mg of by-product. Pure water is defined as water with a resistivity of 18.2 MΩ·cm or higher. After stirring the mixture with a fluororesin spatula or similar tool, the petri dish is covered and the mixture is left to stand for at least 1 hour. Then, the lid of the petri dish is removed and the mixture is left to stand at room temperature for at least 24 hours to allow the water to evaporate from the mixture. The solid obtained in this way is then crushed using a fluororesin spatula or similar tool to obtain a powder. This powder is dried with a vacuum pump under reduced pressure of 5 Pa or less for at least 2 hours to obtain the sample for measurement.

[0041] Next, the sample is divided into a 3.2 mm zirconia sample tube (708239971) manufactured by JEOL Ltd. This NMR sample tube is then placed inside the NMR spectrophotometer. 29 The Si NMR spectrum is measured. As an NMR spectrophotometer, for example, the JNM-ECA800 manufactured by JEOL Ltd. can be used. 29 For measuring Si NMR spectra, for example, the number of integration cycles is set to 4096, and the measurement range is set to between -250 ppm and 250 ppm.

[0042] The hydrolysis product obtained in this manner relates to the hydrolysis product obtained in this manner. 29 In the Si NMR spectrum, peaks appearing within the range of -120 ppm to -10 ppm are thought to originate from at least one of the siloxane bond and the silanol group. Therefore, if a peak is present within this range, it can be presumed that the hydrolysis product contains at least one of the siloxane bond and the silanol group.

[0043] Furthermore, by combining the results of nuclear magnetic resonance spectroscopy obtained in this manner with the results of elemental analysis, the structural formula of the hydrolysis product can be estimated.

[0044] Elemental analysis involves quantitative analysis of carbon (C), hydrogen (H), nitrogen (N), halogen elements, and sulfur (S) contained in by-products. The halogen elements are fluorine (F), chlorine (Cl), and bromine (Br). For the analysis of carbon, hydrogen, and nitrogen, for example, JM-11 manufactured by J-Science Lab Co., Ltd. is used. For the analysis of halogens and sulfur, for example, YHS-11 manufactured by Yanaco Corporation is used.

[0045] In elemental analysis of the hydrolysis product, if the hydrogen content is between 1% and 10% by mass, and the halogen element content is 20% or less by mass, then it can be said that hydrolysis reduced the amount of halogen in the byproduct and increased the amount of hydrogen. The hydrogen content may also be between 1% and 4% by mass, and the halogen element content may be 1.5% or less by mass. 29 From the Si NMR spectrum results, the increased hydrogen is thought to originate from the Si-OH bond. Therefore, it is thought that the halogen in the by-product is replaced by a hydroxyl group through hydrolysis. Furthermore, since the hydrogen abundance is within the above range, the structural formula of the hydrolysis product consisting only of silicon, oxygen, and hydrogen is estimated to be (24) to (27) below.

[0046] [ka]

[0047] The compounds represented by structural formulas (24), (26), and (27) above possess both siloxane bonds and silanol groups. Furthermore, the compounds represented by structural formulas (24) to (27) above are polysilanols having two or more silanol groups.

[0048] In the compound of structural formula (24), the abundance of hydrogen is 2.961% by mass. In the compound of structural formula (25), the abundance of hydrogen is 3.82% by mass, the abundance of oxygen is 60.67% by mass, and the abundance of silicon is 35.50% by mass. In the compound of structural formula (26), the abundance of hydrogen is 2.88% by mass, the abundance of oxygen is 57.06% by mass, and the abundance of silicon is 40.07% by mass. In the compound of structural formula (27), the abundance of hydrogen is 2.63% by mass, the abundance of oxygen is 48.61% by mass, and the abundance of silicon is 48.76% by mass.

[0049] Siloxane bonds and Si-Si bonds contained in hydrolysis products can be explosive or flammable. In particular, the cyclic siloxane bonds in structural formulas (26) to (27) and the cyclic silicon ring in structural formula (27) can release a large amount of energy when the bond is broken. Therefore, compounds containing these rings are thought to be flammable.

[0050] When such hydrolysis products are brought into contact with the treatment solution according to the embodiment, Si-H bonds, siloxane bonds, and Si-Si bonds can be cleaved, thereby safely rendering the hydrolysis products harmless.

[0051] The mixture may contain siloxanes or silica, etc. Siloxanes contain Si-O bonds or Si-O-Si bonds.

[0052] The presence of siloxanes in a mixture can be confirmed by Fourier transform infrared (FT-IR) spectroscopy. Specifically, if a peak attributed to Si-O-Si is detected in the infrared spectrum, it can be inferred that the mixture contains siloxanes. For example, the peak attributed to Si-O-Si in the infrared spectrum is at 900 cm⁻¹. -1 More than 1700cm -1 It was detected within the following range, and according to other examples, 900 cm. -1 More than 1300cm -1 It is detected within the following range.

[0053] Specifically, first, the by-product is collected as a mixture using the same method as described above. Next, an infrared spectroscopic spectrum is obtained from this by-product using the Attenuated Total Reflection (ATR) method. For infrared spectroscopic analysis, the infrared spectrometer is placed in a nitrogen-purged glove box. For example, an ALPHA manufactured by Bruker Optics is used as the infrared spectrometer. Germanium (Ge) is used as the ATR crystal. For example, the analysis conditions are set to an incident angle of 45°, 512 integrations, and a measurement range of 500 cm². -1 More than 4000cm -1 The following applies, with a resolution of 4cm. -1 Let's assume that.

[0054] A mixture that may contain at least one of halosilanes and hydrolysis products may be included, for example, as a by-product of a reaction that forms silicon-containing substances using a gas containing silicon and halogen elements. Specifically, it may be produced in the reaction described below. Figure 1 shows an example of an epitaxial growth apparatus (silicon-containing substance formation apparatus) as a device that generates the aforementioned mixture that may contain halosilanes or hydrolysis products. The epitaxial growth apparatus 1 in the example of Figure 1 comprises an apparatus body 2, a pollution control device 3, and a connection part 5. The apparatus body 2 comprises a housing 6, a reaction chamber 7, a discharge pipe 8, and a supply pipe (not shown). The reaction chamber 7, the discharge pipe 8, and the supply pipe are housed in the housing 6. One end of the supply pipe is connected to the reaction chamber 7, and the other end of the supply pipe is connected to a supply device (not shown) which includes a source of raw material gas, which is the raw material substance.

[0055] One end of the discharge pipe 8 is connected to the reaction chamber 7, and the other end of the discharge pipe 8 is connected to the connection part 5. The discharge pipe 8 includes (five pipes in the example in Figure 1) piping 11-15. In the main body of the apparatus 2, the pipes are arranged in the order of 11, 12, 13, 14, and 15 from the proximal side (upstream side) to the reaction chamber 7. A chamber isolation valve (CIV) 16 is located in pipe 12, and a pressure control valve (PCV) 17 is located in pipe 13. When the chamber isolation valve 16 is closed, maintenance can be performed only on the part of the discharge pipe 8 opposite to the chamber isolation valve 16 (downstream side) from the reaction chamber 7. One end of the connection part 5 is connected to piping 15 of the discharge pipe 8, and the other end of the connection part 5 is connected to the pollution control device 3. The connection part 5 includes (two pipes in the example in Figure 1) piping 18 and 19. In the epitaxial growth apparatus 1, the pipes 18 and 19 are arranged in the order of proximal (upstream) to the apparatus body 2.

[0056] In the epitaxial growth apparatus 1, the raw material gas is supplied as a raw material from a supply device via a supply pipe and introduced into the reaction chamber 7. The raw material gas is a gas containing silicon and halogen elements. Therefore, the raw material gas contains one or more halogen elements and silicon. The gas containing silicon and halogen elements is, for example, a mixed gas of a compound containing silicon and halogen elements and hydrogen. The concentration of hydrogen in this mixed gas is, for example, 95% by volume or more. The compound containing silicon and halogen elements includes one or more compounds selected from the group consisting of compounds containing silicon and chlorine, compounds containing silicon and bromine, compounds containing silicon and fluorine, and compounds containing silicon and iodine. Furthermore, the compound containing silicon and halogen elements includes halosilanes.

[0057] Compounds containing silicon and chlorine include, for example, one of the chlorosilanes such as dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), and tetrachlorosilane (SiCl4), or mixtures thereof. When a compound containing silicon and chlorine is included in the mixed gas, the mixed gas may also contain at least one of monosilane (SiH4) and hydrogen chloride (HCl). Compounds containing silicon and bromine include, for example, one of the bromosilanes such as dibromosilane (SiH2Br2), tribromosilane (SiHBr3), and tetrabromosilane (SiBr4), or mixtures thereof. When a compound containing silicon and bromine is included in the mixed gas, the mixed gas may also contain at least one of monosilane (SiH4) and hydrogen bromide (HBr).

[0058] The raw material gas may contain two or more halogen elements, and the raw material gas may contain chlorine plus one or more halogen elements other than chlorine. In one example, the raw material gas is a mixture of a compound containing silicon and chlorine, hydrogen gas, and at least one of a compound containing a halogen element other than chlorine and a halogen gas other than chlorine gas. The compound containing a halogen element other than chlorine may or may not contain silicon. In another example, the raw material gas is a mixture of a compound containing a halogen element other than chlorine and silicon, hydrogen gas, and at least one of a compound containing chlorine and chlorine gas. The compound containing chlorine may or may not contain silicon.

[0059] Furthermore, the reaction chamber 7 can be depressurized by the pressure regulating valve 17. When the reaction chamber 7 is depressurized by the pressure regulating valve 17, the pressure in the discharge pipe 8 increases in the region opposite the reaction chamber 7 to the pressure regulating valve 17 compared to the region on the reaction chamber 7 side of the pressure regulating valve 17. In the epitaxial growth apparatus 1, the substrate is placed in the reaction chamber 7 while the pressure in the reaction chamber 7 is depressurized. In the reaction chamber 7, the raw material gas supplied via the supply pipe reacts with the substrate. At this time, the substrate is heated to a temperature above the reaction temperature with the raw material gas. In one example, the reaction temperature is 600°C or higher, and in another example, the reaction temperature is 1000°C or higher. As described above, a single-crystal or polycrystalline silicon-containing film is formed on the substrate by a thermochemical reaction between the raw material gas and the substrate under reduced pressure and high temperature. The substrate is, for example, a single-crystal silicon substrate.

[0060] The exhaust gas, which is the waste product from the reaction chamber 7, is discharged to the pollution control device 3 via the discharge pipe 8 and the connection part 5. Therefore, the discharge pipe 8 and the connection part 5 form the discharge path from the reaction chamber 7. The exhaust gas may contain some of the silicon and halogen element compounds contained in the raw material gas that did not deposit on the substrate. For this reason, the exhaust gas may contain some of the halosilanes contained in the raw material gas that did not deposit on the substrate. In addition, the exhaust gas may contain some of the silicon and halogen element compounds contained in the raw material gas that did not react in the reaction chamber 7. Furthermore, the exhaust gas may contain halosilanes produced by the reaction of halogen element and silicon-containing compounds in the reaction chamber 7. Moreover, the exhaust gas, which is the waste product, may contain the aforementioned monosilane (SiH4), as well as hydrogen halides such as hydrogen chloride (HCl) and hydrogen bromide (HBr). The exhaust gas is rendered harmless by combustion in the pollution control device 3.

[0061] By-products generated in the reaction between the raw material gas and the substrate may precipitate in parts of the exhaust pipe 8 and the connection section 5. These by-products are formed when components contained in the exhaust gas react and solidify or liquefy. For example, by-products may be generated when halosilanes contained in the exhaust gas react with each other in the exhaust pipe 8 or the connection section 5. By-products may also be generated when halosilanes react with other components contained in the exhaust gas in the exhaust pipe 8 or the connection section 5. As by-products are generated as described above, these by-products include the aforementioned halosilanes. The generated by-products may adhere to the inner surfaces of pipes 11-15 of the exhaust pipe 8 and pipes 18 and 19 of the connection section 5, etc.

[0062] Here, the temperature is higher in pipes 11, 12, etc., which are located proximal to the reaction chamber 7. Also, the region of pipes 11, 12, etc., on the reaction chamber 7 side relative to the pressure regulating valve 17 is depressurized, just like the reaction chamber 7. For this reason, polymerization of components contained in the exhaust gas is less likely to occur in the region of pipes 11, 12, etc., on the reaction chamber 7 side relative to the pressure regulating valve 17, and thus by-products are less likely to be formed.

[0063] Furthermore, as mentioned above, the pressure increases in the region opposite the reaction chamber 7 to the pressure regulating valve 17 compared to the region on the reaction chamber 7 side of the pressure regulating valve 17. Therefore, the pressure increases downstream of the pressure regulating valve 17 compared to the upstream side. Consequently, it is considered that in the region adjacent to the downstream side of the pressure regulating valve 17, the reactions between components contained in the exhaust gas proceed more easily, and by-products are more likely to be produced. For this reason, it is considered that by-products are particularly likely to be produced in the downstream portion of piping 13 relative to the pressure regulating valve 17, and in piping 14. Note that the aforementioned reactions between components contained in the exhaust gas are less likely to occur under reduced pressure.

[0064] Furthermore, in the piping 15 and connection points 5 located downstream from the pressure regulating valve 17, the amount of components that serve as raw materials for by-products in the exhaust gas decreases. For this reason, it is considered that by-products are less likely to be generated in the piping 15 and connection points 5.

[0065] Furthermore, the by-products may include not only halosilanes but also hydrolysis products that can be formed when halosilanes come into contact with water. The by-products may also include silica.

[0066] In the processing methods of the embodiments described later, the aforementioned by-products may become the mixture to be processed. In this case, pipes 11-15, 18, and 19 on which by-products have accumulated are used as the components to be processed. Therefore, the components to be processed contain by-products. In particular, by-products adhering to pipes 13, 14, etc., which are considered to be prone to by-product accumulation, are processed by the processing methods of the embodiments described later. As mentioned above, mixtures containing halosilanes or hydrolysis products of halosilanes can be transformed into explosive substances in the air. Therefore, it is necessary to detoxify the mixture, and according to the embodiments, a processing method for detoxifying the mixture is provided.

[0067] Furthermore, the apparatus for generating the aforementioned halosilanes or mixtures containing hydrolysis products of halosilanes is not limited to the epitaxial growth apparatus described above. In one example of a silicon-containing material formation apparatus, silicon-containing raw material and halogen-containing raw material are supplied to each other via separate routes in the reaction chamber (e.g., 7). Here, the silicon-containing raw material may include powdered (solid) silicon. The halogen-containing raw material may be a raw material gas containing hydrogen halides such as hydrogen chloride.

[0068] In the silicon-containing material formation apparatus, no substrate such as a silicon substrate is provided in the reaction chamber (e.g., 7). In the reaction chamber, silicon-containing raw materials and halogen-containing raw materials, which are introduced separately to each other, react. Halosilanes and hydrogen are produced by the reaction of silicon-containing raw materials and halogen-containing raw materials. Then, silicon-containing material is obtained by the reaction of halosilanes and hydrogen. The halosilanes produced by the reaction of silicon-containing raw materials and halogen-containing raw materials may include chlorosilanes such as trichlorosilane (SiHCl3). In addition, hydrogen halides and silicon tetrahalides may be generated in the reaction in the reaction chamber.

[0069] Even in a silicon-containing material formation apparatus, the exhaust gas (emissions) discharged from the reaction chamber contains halosilanes, and the halosilanes in the exhaust gas may include chlorosilanes such as the aforementioned trichlorosilane. Furthermore, the exhaust gas from the reaction chamber may contain hydrogen, as well as hydrogen halides and silicon tetrahalides generated in the reaction chamber. The hydrogen halides generated in the reaction chamber may include hydrogen chloride (HCl). And the silicon tetrahalides generated in the reaction chamber may include silicon tetrachloride (SiCl4).

[0070] Furthermore, in the silicon-containing material formation apparatus, a cooling mechanism is provided in the discharge path (discharge pipe 8) for the exhaust gas (exhaust material) from the reaction chamber to cool the exhaust gas. The exhaust gas is cooled by the cooling mechanism and liquefied. The liquefied substance (exhaust material) resulting from the liquefied exhaust gas is then recovered.

[0071] Even in silicon-containing material formation apparatuses, by-products may precipitate in the discharge path due to the liquefaction of the exhaust gas by the cooling mechanism. These by-products may include a portion of the liquid exhaust gas that remains in the discharge path without being recovered. The by-products may also include halosilanes contained in the exhaust gas, as well as hydrolysis products of halosilanes. The hydrolysis products of halosilanes may be solid substances. The by-products may also include silicon tetrahalides contained in the exhaust gas. Furthermore, by-product precipitation is particularly likely to occur in and near the cooling mechanism in the discharge path.

[0072] As mentioned above, even in a silicon-containing material forming apparatus, a mixture containing halosilanes and / or hydrolysis products of halosilanes may precipitate as a by-product, for example, in the discharge pathway. The above mixture generated as a by-product in the silicon-containing material forming apparatus can also be transformed into an explosive substance in the atmosphere. For this reason, it is necessary to detoxify the by-product, and according to the embodiment, a treatment method for detoxifying the above mixture is provided.

[0073] The treatment method of this embodiment is characterized by treating a mixture containing one or both halosilanes and hydrolysates of halosilanes by contacting the mixture with a treatment solution having a pH of 8 to 14 and in an amount equivalent to 100 times or more the mass of the mixture. This method makes the reaction during detoxification treatment milder and suppresses the temperature rise during treatment, thus enabling safe treatment.

[0074] The mechanism of detoxification treatment involves using a mixture, for example, (SiCl2) n We will explain using oily silanes such as the one shown, and a basic aqueous solution as the treatment solution, as an example. When an oily silane is brought into contact with a basic aqueous solution, the first reaction shown in (1) occurs.

[0075] [ka]

[0076] The reaction between oily silane and water shown in the first reaction is an exothermic reaction. The hydrogen chloride produced in the first reaction reacts with the base (BOH) as shown in equation (2) (second reaction). Neutralization heat is released in the second reaction.

[0077] [ka]

[0078] Furthermore, the hydrolysate produced in the first reaction is rendered harmless according to the third reaction shown in equation (3). This is because the Si-Si bond and siloxane bond are cleaved, resulting in the loss of explosive properties.

[0079] [ka]

[0080] The reason for setting the pH of the treatment solution to a range of 8 to 14 is explained below. A basic treatment solution with a pH within this range can decompose halosilanes and their hydrolysis products without generating any new explosive substances. For example, the Si-Si bonds and Si-X (where X is at least one halogen element) bonds in cyclic halosilanes are cleaved. On the other hand, in the hydrolysis products, the Si-Si bonds and siloxane bonds are cleaved. Therefore, the treatment solution after this reaction contains virtually no explosive or flammable substances. Also, hydrogen halides (e.g., HCl) may be generated during this reaction as shown in equation (1) above. Therefore, the pH of the treatment solution tends to decrease during this reaction. By using a basic treatment solution that satisfies the above pH, these hydrogen halides can be neutralized as shown in equation (2), thus suppressing a decrease in the pH of the treatment solution. A more preferable pH range is 8 to 13.

[0081] By making the mass of the basic treatment solution that satisfies the pH range above 100 times or more the mass of the mixture, the heat capacity of the treatment solution can be increased, thereby suppressing the temperature rise due to the heat of reaction. As a result, the reaction proceeds slowly, allowing for smooth diffusion and exhaust of the generated hydrogen, and preventing hydrogen from remaining in the reaction system. Furthermore, because the mass of the treatment solution is large, the base concentration can be lowered when using a strong base with a base dissociation constant Kb greater than 1. As a result, the neutralization reaction in equation (2) proceeds slowly, thus reducing the reaction rate in the subsequent reaction in equation (3). Also, because the neutralization reaction in equation (2) proceeds slowly, the hydrogen halide concentration in the treatment solution increases, and the reaction in equation (1) also occurs slowly. Therefore, the reaction rates of the series of reactions from equation (1) to (3) are reduced, thus suppressing the temperature rise during treatment. On the other hand, when using a weak base with a base dissociation constant Kb of less than 1, even if the base concentration of the treatment solution is high, the heat capacity of the treatment solution is large, which suppresses the temperature rise during treatment. Therefore, regardless of the base dissociation constant Kb, safe detoxification treatment can be performed.

[0082] The pH of the treatment solution is preferably between 8 and 14 before and after treatment. If the pH after treatment is less than 8, the neutralization reaction in (2) may not have been completed. Therefore, the subsequent detoxification reaction in (3) may also not have been completed.

[0083] On the other hand, using a neutral aqueous solution as the treatment solution may produce explosive or flammable substances. This is thought to be because, when a mixture containing halosilanes reacts with a neutral aqueous solution, only the surface of the mixture is hydrolyzed, and the halosilanes present inside are not decomposed. Alternatively, when the mixture reacts with water, hydrolysis can break the Si-Cl bonds in the mixture, but it is thought that products having at least one of Si-Si, Si-O-Si, and Si-OH bonds are produced. Furthermore, when a neutral or acidic aqueous solution is used, hydrogen halides (e.g., hydrogen chloride) cannot be neutralized, resulting in a very low pH of the treatment solution after the reaction, which can be corrosive. For these reasons, using a neutral or acidic aqueous solution is less safe than using a basic aqueous solution that satisfies the above pH range.

[0084] Based on the above, according to the embodiment, a mixture containing one or both halosilanes and hydrolysates of halosilanes can be safely rendered harmless without causing an explosion.

[0085] The mass of the treatment solution should be at least 100 times the mass of the mixture. However, if it is too large, the concentration of the treatment solution will decrease, leading to longer processing times, or the container (e.g., tank) for the treatment solution will need to be larger, resulting in a larger processing device. To improve the cost and efficiency of the process, it is desirable to keep the mass of the treatment solution at 10,000 times or less the mass of the mixture.

[0086] The mass of a mixture containing halosilanes and / or their hydrolysates can be determined by subtracting the mass of the component (e.g., a pipe) from the total mass of the mixture and the component when the mixture is contained in or attached to the component. On the other hand, the mass of the treatment liquid can be determined from its volume when the specific gravity of the treatment liquid is set to 1.

[0087] To react the mixture with the treatment solution, it is preferable to collect the mixture under an inert atmosphere, and to maintain the mixture under an inert atmosphere until immediately before the reaction, it is preferable to react the mixture with the treatment solution under an inert atmosphere. By controlling the mixture under an inert atmosphere, it is possible to prevent it from reacting with water and oxygen not only inside the mixture mass but also on its surface. The inert gas is, for example, nitrogen gas, argon gas, or a mixture thereof. Under an inert atmosphere, it is preferable that the dew point is -50°C or lower and the oxygen concentration is 10 ppm or lower.

[0088] In the processing method, the mixture may be brought into contact with the processing solution either by adding the processing solution to the mixture or by adding the mixture to the processing solution. Adding the mixture to the processing solution is preferable because it results in a gentler reaction. Furthermore, the processing may be carried out in multiple stages. Specifically, first, a hydrolysis reaction of the halosilanes is induced by reacting the mixture containing halosilanes with water. The water may be added to the mixture or by adding the mixture to the water. The hydrolysis treatment yields a primary treated product containing the hydrolysis products of the halosilanes and water. The primary treated product may contain unreacted halosilanes. Next, the primary treated product is brought into contact with the processing solution. The reaction site in which the processing is carried out may be the same as or different from the reaction site in which the hydrolysis treatment is performed.

[0089] Furthermore, hydrogen (H2) gas may be generated when the mixture reacts with the treatment liquid. Therefore, it is preferable to carry out this treatment in a facility equipped with a gas exhaust mechanism. Examples of gas exhaust mechanisms include ducts, fans, and pumps. It is also preferable to subject the mixture of the mixture and the treatment liquid to ultrasonic treatment using an ultrasonic cleaner. That is, by vibrating the mixture and the treatment liquid with ultrasound, the dispersibility of the mixture in the treatment liquid can be increased without using stirring rods or the like. The ultrasonic frequency is preferably 20 kHz or higher.

[0090] Here, the mixture can accumulate on the piping as a highly viscous liquid substance. Therefore, in the mixture deposits, it is thought that the halosilanes with cyclic structures present on the surface decompose into substances that do not contain Si-Si bonds through reaction with water and oxygen. On the other hand, chlorosilanes with cyclic structures containing Si-Si bonds present inside the mixture deposits are less likely to come into contact with water and oxygen, and are therefore thought to maintain their cyclic structure even in the atmosphere. Consequently, treatment of the mixture with a basic treatment solution is effective even in the atmosphere.

[0091] Next, we will describe the processing solutions that can be used in this processing method.

[0092] The treatment solution is a basic aqueous solution containing at least one of an inorganic base or an organic base. In the treatment solution, the concentrations of the inorganic base and the organic base are, for example, 0.01% by mass or more and 30% by mass or less, preferably 0.1% by mass or more and 10% by mass or less.

[0093] As the inorganic base, at least one selected from the group consisting of, for example, metal hydroxides, alkali metals, carbonates, bicarbonates, and metal oxides is used.

[0094] Examples of metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, magnesium hydroxide, copper hydroxide, iron hydroxide, zinc hydroxide, aluminum hydroxide, or mixtures thereof.

[0095] Alkali metals include, for example, elemental potassium, elemental lithium, elemental sodium, or mixtures thereof.

[0096] Carbonates include, for example, sodium carbonate, potassium carbonate, ammonium carbonate, potassium carbonate, lithium carbonate, barium carbonate, magnesium carbonate, or mixtures thereof.

[0097] Examples of bicarbonates include sodium bicarbonate, ammonium bicarbonate, potassium bicarbonate, calcium bicarbonate, or mixtures thereof.

[0098] Metal oxides include, for example, calcium oxide, magnesium oxide, sodium oxide, or mixtures thereof.

[0099] The inorganic base includes, for example, at least one selected from the group consisting of alkali metal element hydroxides, alkali metal element carbonates, alkali metal element bicarbonates, alkaline earth metal element hydroxides, alkaline earth metal element carbonates, and ammonium hydroxide (NH4OH).

[0100] Furthermore, the inorganic base is preferably at least one selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium carbonate (Na2CO3), calcium hydroxide (Ca(OH)2), lithium hydroxide (LiOH), sodium bicarbonate (NaHCO3), and ammonium hydroxide (NH4OH). Since such inorganic bases have low toxicity, using them allows for safer processing of mixtures.

[0101] Furthermore, it is more preferable that the inorganic base is at least one selected from the group consisting of potassium hydroxide (KOH), sodium carbonate (Na2CO3), lithium hydroxide (LiOH), sodium bicarbonate (NaHCO3), and ammonium hydroxide (NH4OH). Using such an inorganic base allows the reaction to proceed more gently, making it possible to process the product more safely.

[0102] As the organic base, at least one selected from the group consisting of alkylammonium hydroxides, organometallic compounds, metal alkoxides, amines, and heterocyclic amines is used.

[0103] Alkylammonium hydroxides include, for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline hydroxide, or mixtures thereof.

[0104] Organometallic compounds include, for example, organolithium, organomagnesium, or mixtures thereof. Organolithium includes, for example, butyllithium, methyllithium, or mixtures thereof. Organomagnesium includes, for example, butylmagnesium, methylmagnesium, or mixtures thereof.

[0105] Metal alkoxides include, for example, sodium ethoxide, sodium butoxide, potassium ethoxide, potassium butoxide, sodium phenoxide, lithium phenoxide, sodium ethoxide, or mixtures thereof.

[0106] The amines are methylamine, dimethylamine, trimethylamine, triethylamine, ethylenediamine, diethylamine, aniline, or mixtures thereof.

[0107] Heterocyclic amines are pyridine, pyrrolidine, imidazole, piperidine, or mixtures thereof.

[0108] The organic base is preferably at least one selected from the group consisting of sodium phenoxide (C6H5ONa), 2-hydroxyethyltrimethylammonium hydroxide (choline hydroxide), and tetramethylammonium hydroxide (TMAH).

[0109] Processing solutions containing organic bases tend to react more gently with mixtures compared to processing solutions containing only inorganic bases, thus allowing for safer processing of mixtures. Processing solutions containing organic bases are more suitable for use in cleanrooms compared to processing solutions containing only inorganic bases. Mixtures containing one or both of halosilanes and their hydrolysates are generated in semiconductor manufacturing processes, such as in epitaxial growth equipment. Such semiconductor manufacturing processes are carried out in cleanrooms where minute dust particles in the air have been removed, because even trace amounts of foreign matter can cause defects and other problems if they adhere to the semiconductor. In particular, metallic foreign matter has a significant impact on the quality when it adheres to the semiconductor, so thorough removal is required. Ammonia, although it does not contain metallic elements, acts as an inhibitor of chemically amplified photoresists, so its use in cleanrooms is avoided. Organic bases that do not contain any alkaline earth metals or alkali metal elements, such as TMAH, or those that contain a smaller proportion of these elements per unit mass compared to inorganic bases, such as C6H5ONa, can be used. Therefore, when a processing solution containing an organic base is used, contamination by metallic foreign matter or ammonia in the cleanroom can be suppressed compared to when a processing solution containing only an inorganic base is used, and consequently, the manufacturing efficiency of semiconductors can be improved.

[0110] Examples of bases with a base dissociation constant Kb greater than 1 include choline hydroxide, TMAH, and NaOH. Among bases with a base dissociation constant Kb greater than 1, preferred are organic bases such as alkylammonium hydroxides, including choline hydroxide and TMAH. Since choline hydroxide and TMAH do not contain alkaline earth metals and alkali metal elements, respectively, contamination of the treated material with these elements can be avoided.

[0111] On the other hand, examples of bases with a base dissociation constant Kb of less than 1 include sodium bicarbonate and sodium phenoxide. Among bases with a base dissociation constant Kb of less than 1, sodium bicarbonate (NaHCO3) is preferred. Because sodium bicarbonate has a smaller molecular weight than organic bases with a base dissociation constant Kb of less than 1, its molar concentration can be increased compared to organic bases with a base dissociation constant Kb of less than 1 when the mass percent concentration is constant. Therefore, processing can proceed smoothly.

[0112] Water is used as the solvent for the processing solution. The water may be pure water, deionized water, purified water, or tap water, or a mixture thereof.

[0113] The treatment solution may contain optional components such as surfactants and pH buffers, in addition to inorganic and organic bases.

[0114] Surfactants enhance the dispersibility of the mixture in the processing solution and improve the processing speed. The concentration of the surfactant in the processing solution is, for example, 0.01% by mass or more and 10% by mass or less, preferably 0.1% by mass or more and 1% by mass or less.

[0115] The surfactant includes, for example, at least one selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0116] Anionic surfactants include, for example, sodium laurate, sodium stearate, sodium lauryl sulfate, sodium 1-hexanesulfonate, lauryl phosphoric acid, or mixtures thereof.

[0117] Cationic surfactants include, for example, tetramethylammonium chloride, benzalkonium chloride, octyltrimethylammonium chloride, monomethylamine hydrochloride, butylpyridinium chloride, or mixtures thereof.

[0118] Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, cocamidobromyl betaine, sodium lauroyl glutamate, lauryldimethylamine N-oxide, or mixtures thereof.

[0119] Nonionic surfactants include, for example, glyceryl laurate, pentaethylene glycol onododecyl ether, polyoxyethylene sorbitan fatty acid ester, lauric acid diethanolamide, octyl glucoside, cetanol, or mixtures thereof.

[0120] The surfactant preferably contains at least one of benzalkonium chloride and sodium laurate, and more preferably benzalkonium chloride.

[0121] pH buffers play a role in maintaining a constant pH in the treatment solution during the processing of a mixture. By using a pH buffer, it is possible to prevent the pH of the solution after the mixture decomposition treatment from becoming excessively high or excessively low. Therefore, using a pH buffer allows for safer detoxification of the mixture.

[0122] The concentration of the pH buffer in the processing solution is, for example, 0.01% by mass or more and 30% by mass or less, preferably 0.1% by mass or more and 10% by mass or less.

[0123] As pH buffers, mixtures of a weak acid and its conjugate base, or mixtures of a weak base and its conjugate acid can be used. Examples of pH buffers include mixtures of acetic acid (CH3COOH) and sodium acetate (CH3COONa), mixtures of citric acid and sodium citrate, or mixtures of trishydroxymethylaminomethane (THAM) and ethylenediaminetetraacetic acid (EDTA).

[0124] Figure 2 shows an example of a processing apparatus used in the method according to the embodiment, which processes the aforementioned mixture. As shown in Figure 2, the processing apparatus 20 includes a control unit (controller) 21, an aqueous solvent tank 22, a processing liquid tank 23, a processing tank 25, a supply mechanism (supply system) 26, an exhaust mechanism (exhaust system) 27, a sensor 28, a jig 30, a dispersion mechanism (disperser) 31, a stirring mechanism (agitator) 32, a liquid circulation mechanism (liquid circulator) 33, a liquid discharge mechanism (liquid discharge system) 35, a waste liquid tank 36, a temperature sensor 50, and a cooling unit 51. In Figure 2, the flow of fluids such as liquids and gases is indicated by solid arrows, and electrical signals such as input signals to the control unit 21 and output signals from the control unit 21 are indicated by dashed arrows.

[0125] The control unit 21 controls the entire processing unit 20. The control unit 21 includes a processor or integrated circuit (control circuit) including a CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), or FPGA (Field Programmable Gate Array), and a storage medium such as memory. The control unit 21 may have only one processor or integrated circuit, or it may have multiple processors or integrated circuits. The control unit 21 performs processing by executing a program or the like stored in the storage medium. Temperature measurement information from the temperature sensor 50 is input to and stored in the storage medium. The processor and integrated circuit obtain the amount of temperature change of the processing liquid based on the temperature measurement information read from the storage medium.

[0126] The aqueous solvent tank 22 stores aqueous solvent. The aqueous solvent may be water alone, or a liquid (e.g., an aqueous solution) in which necessary additives are dissolved or mixed with water. Examples of additives include surfactants and pH buffers. The treatment liquid tank 23 stores treatment liquid. The treatment liquid is used to detoxify the aforementioned mixture. The treatment liquid also contains an alkaline aqueous solution. The treated member 37, to which the aforementioned by-products are attached as a mixture, is introduced into the treatment tank 25. At this time, for example, the pipes 11-15 in the example of Figure 1, to which the by-products are attached, are introduced into the treatment tank 25 as the treated member 37. Therefore, the treated member 37 contains by-products. The discharge pipe 8 is disassembled into individual pipes and introduced into the treatment tank 25.

[0127] The supply mechanism (liquid supply mechanism) 26 enables the supply of water solvent from the water solvent tank 22 to the treatment tank 25, and also enables the supply of treatment liquid from the treatment liquid tank 23 to the treatment tank 25. In this embodiment, the supply mechanism 26 includes a supply line 41 and valves 42 and 43. The supply line 41 is formed, for example, from one or more pipes. In this embodiment, the treatment tank 25 is connected to the water solvent tank 22 and the treatment liquid tank 23 via the supply line 41. In this embodiment, the operation of valves 42 and 43 is controlled by a control unit 21, and the control unit 21 switches the opening and closing of valves 42 and 43, respectively.

[0128] When valves 42 and 43 are closed, neither water solvent nor processing liquid is supplied to the processing tank 25. When valve 42 is opened, water solvent is supplied from the water solvent tank 22 to the processing tank 25 through the supply line 41. When valve 43 is opened, processing liquid is supplied from the processing liquid tank 23 to the processing tank 25 through the supply line 41. In one embodiment, the control unit 21 switches the opening and closing of valves 42 and 43 based on the operator's operation on an operating device (not shown), such as a user interface. However, the switching of valves 42 and 43 does not necessarily have to be done by the control unit 21, and in another embodiment, the switching of valves 42 and 43 may be done by the operator without going through the control unit 21.

[0129] In the treatment tank 25, by-products adhering to the member to be treated 37 are neutralized by the treatment liquid supplied by the supply mechanism 26. In one embodiment, during the neutralization of by-products, the treatment liquid is supplied to the treatment tank 25 after the member to be treated 37 has been introduced into the treatment tank 25. In another embodiment, during the neutralization of by-products, the treatment liquid is supplied to the treatment tank 25, and the member to be treated 37 is introduced into the treatment tank 25 while the supplied treatment liquid has accumulated in the treatment tank 25. During the neutralization process, once the treatment liquid has accumulated to a certain level in the treatment tank 25, the valve 43 is closed to stop the supply of the treatment liquid to the treatment tank 25.

[0130] Furthermore, the detoxification reaction of by-products by the aforementioned processing liquid generates gas. The gas generated in the reaction to detoxify the by-products contains hydrogen. The gas generated in the reaction to detoxify the by-products may also contain hydrogen halides such as hydrogen chloride. The exhaust mechanism (gas discharge mechanism) 27 exhausts the gas generated by the reaction between the by-products and the processing liquid from the processing tank 25. The exhaust mechanism 27 includes an exhaust line 45. The exhaust line 45 is formed, for example, from one or more pipes. In one embodiment, the exhaust line 45 is formed from the processing tank 25 to the outside of the room (environment) where the worker performs their work. The gas generated in the reaction to detoxify the by-products is exhausted to the outside of the room where the worker performs their work via the exhaust line 45. In one embodiment, the gas exhausted to the outside of the room is recovered and detoxified.

[0131] The gas generated in the reaction that neutralizes the by-products is mainly hydrogen. Hydrogen is lighter than air. For this reason, it is preferable that the connection between the exhaust line 45 and the processing tank 25 be located in the vertically upper part of the internal space of the processing tank 25. In one embodiment, the exhaust mechanism 27 is equipped with a suction source (not shown), such as a suction pump. The aforementioned gas is exhausted by applying a suction force to the internal space of the processing tank 25 and the exhaust line 45 using the suction source. In this case, the drive of the suction source may be controlled by the control unit 21.

[0132] The sensor 28 detects parameters related to the progress of the reaction between the treatment solution and the by-products during the detoxification treatment of by-products. The sensor 28 may be integrated with the treatment tank 25, or it may be detachably attached to the treatment tank 25. In some embodiments, the sensor 28 may be provided separately from the treatment tank 25 and may not be mechanically connected to the treatment tank 25. The sensor 28 may include, for example, one or more of a pH meter, a Raman spectrometer, an infrared spectroscopy (IR) analyzer, and a nuclear magnetic resonance (NMR) spectrometer. In some embodiments, the sensor 28 is equipped with a pH meter.

[0133] In one embodiment, the control unit 21 acquires the detection result from the sensor 28. Based on the detection result from the sensor 28, the control unit 21 determines the progress of the detoxification process of the by-product and whether the by-product has been properly detoxified. In one embodiment, a notification device (not shown) may be provided to notify that the by-product has been properly detoxified. In this case, if the control unit 21 determines that the by-product has been properly detoxified, it activates the notification device and notifies that the by-product has been properly detoxified. The notification is made by emitting sound, emitting light, or displaying on a screen. In another embodiment, the determination of whether the by-product has been properly detoxified may be made by an operator instead of the control unit 21. In this case, the operator acquires the detection result from the sensor 28 and determines whether the by-product has been properly detoxified based on the acquired detection result.

[0134] As mentioned above, hydrogen halides are produced by the reaction of by-products with the treatment solution. The aqueous solution of hydrogen halides is acidic. Therefore, as the detoxification treatment of the by-products progresses, the pH of the treatment solution decreases. Thus, the progress of the reaction between the treatment solution and the by-products can be appropriately determined based on the pH of the treatment solution, and the progress of the detoxification treatment can be appropriately determined.

[0135] Furthermore, the reaction between the by-product and the treatment solution can alter the interatomic bonding state and molecular structure of the components contained in the by-product. Therefore, the progress of the reaction between the treatment solution and the by-product can be appropriately determined based on the spectral intensity of either the Raman spectrum, IR spectrum, or NMR spectrum, thereby allowing for an appropriate assessment of the progress of the detoxification treatment.

[0136] The jig 30 maintains each of the members to be processed 37 in a predetermined position within the processing liquid of the processing tank 25. At this time, each of the members to be processed 37, such as pipes to which by-products are attached, is maintained with one end of the pipe opening facing vertically upward. That is, each of the members to be processed 37 is maintained with one end of the pipe opening facing the side where the liquid surface of the processing liquid is located. As described above, gas (hydrogen) is generated inside each of the members to be processed 37 in the processing liquid by a reaction that detoxifies the by-products. In this embodiment, since the position of the members to be processed 37 is maintained by the jig 30 as described above, the gas (hydrogen) generated inside each of the members to be processed 37 moves towards the liquid surface of the processing liquid through the opening that faces vertically upward. The gas is then properly exhausted from the liquid surface of the processing liquid through the exhaust line 45. Therefore, it is effectively prevented that gas bubbles generated by the reaction that detoxifies the by-products remain inside each of the members to be processed.

[0137] Furthermore, in this embodiment, as described above, the jig 30 maintains the posture of the members to be treated 37, so that contact between the members to be treated 37 and contact between the members to be treated 37 and the inner walls of each of the treatment tanks 25 is effectively prevented in the treatment liquid. Therefore, damage to the members to be treated (piping) 37 is effectively prevented during the detoxification treatment of by-products.

[0138] The dispersion mechanism 31 disperses the by-product clumps (condensed particles) in the processing liquid of the processing tank 25 in parallel with the detoxification of the by-products by the processing liquid. The stirring mechanism 32 stirs the processing liquid in the processing tank 25 in parallel with the detoxification of the by-products by the processing liquid. The liquid circulation mechanism 33 forcibly creates a circulating flow of the processing liquid in the processing tank 25 in parallel with the detoxification of the by-products by the processing liquid. The reaction between the by-products and the processing liquid is promoted by any one of the following actions: dispersion of by-product clumps by the dispersion mechanism 31, stirring of the processing liquid by the stirring mechanism 32, or creation of a circulating flow of the processing liquid by the liquid circulation mechanism 33, thereby promoting the detoxification of the by-products.

[0139] As the dispersion mechanism 31, for example, any of the following can be used: a high-speed rotary shear type agitator, a colloidal mill, a roll mill, a high-pressure jet type disperser, an ultrasonic disperser, a bead mill, and a homogenizer. In a high-speed rotary shear type agitator, the condensed particles (clumps) of by-products are dispersed by passing them between the high-speed rotating blades and the outer cylinder. In a colloidal mill, the clumps of by-products are flowed together with the processing liquid between two rotating surfaces, thereby applying a shear force to the processing liquid. The clumps of by-products are then dispersed by the shear force of the processing liquid. In a roll mill, the clumps of by-products (condensed particles) are dispersed by passing them between two to three rotating rolls. In a high-pressure jet type disperser, the processing liquid is injected at high pressure onto the parts of the workpiece 37 where by-products have adhered. As a result, the clumps of by-products are dispersed by the collision between the processing liquid and the workpiece (piping) 37. An ultrasonic disperser generates ultrasonic vibrations in the processing liquid, and these vibrations disperse the clumps of by-products. A bead mill uses beads (spheres) as a medium to disperse the clumps of by-products. In this process, the beads are given motion, and the clumps of by-products are dispersed by collisions between the beads, etc. A homogenizer applies high pressure to the processing liquid, generating homovalves in the processing liquid. The generated homovalves then pass through the inside of the processed component (piping) 37, etc., and the clumps of by-products are uniformly dispersed.

[0140] The stirring mechanism 32 can be either a pump or a rotary spring. The pump stirs the processing liquid in the processing liquid of the processing tank 25 by forming a flow of the processing liquid. The rotary spring stirs the processing liquid by rotating in the processing liquid. In addition, any of the aforementioned devices used as the dispersion mechanism 31 can also be used as the stirring mechanism 32. In this case, the aforementioned devices stir the processing liquid in conjunction with the dispersion of by-product clumps.

[0141] A pump can be used as the liquid circulation mechanism 33. In the example shown in Figure 2, the liquid circulation mechanism 33, such as a pump, is provided in a circulation line 46 formed outside the treatment tank 25. In this case, the liquid circulation mechanism 33 forcibly creates a flow of treatment liquid circulating inside the treatment tank 25 and in the circulation line 46. The treatment liquid is agitated by the formation of a circulating flow of treatment liquid in the treatment tank 25. Therefore, the pump or the like used as the liquid circulation mechanism 33 can also be used as an agitation mechanism 32. The circulation line 46 is formed from one or more pipes and is provided separately from the supply line 41 and the liquid discharge line 47 described later. In one embodiment, the circulation line 46 etc. outside the treatment tank 25 is not provided, and the liquid circulation mechanism 33 forcibly creates a circulating flow of treatment liquid only inside the treatment tank 25.

[0142] The control unit 21 controls the operation of the dispersion mechanism 31, the stirring mechanism 32, and the liquid circulation mechanism 33, respectively. In one embodiment, the control unit 21 operates the dispersion mechanism 31, the stirring mechanism 32, and the liquid circulation mechanism 33 based on the operator's operation on an operating device (not shown), such as a user interface. The operation of the dispersion mechanism 31 disperses the clumps of by-products, the operation of the stirring mechanism 32 stirs the processing liquid, and the operation of the liquid circulation mechanism 33 creates a flow in which the processing liquid circulates. In another embodiment, the dispersion mechanism 31, the stirring mechanism 32, and the liquid circulation mechanism 33 may be operated without the control unit 21 by the operator's operation or the like.

[0143] The liquid discharge mechanism 35 discharges the processed liquid, which has reacted with by-products in the processing tank 25, from the processing tank 25. The processed liquid discharged from the processing tank 25 is stored in the waste liquid tank 36. The liquid discharge mechanism 35 includes a liquid discharge line 47 and a valve 48. The liquid discharge line 47 is formed, for example, from one or more pipes. In this embodiment, the processing tank 25 is connected to the waste liquid tank 36 via the liquid discharge line 47. In this embodiment, the operation of the valve 48 is controlled by the control unit 21, which switches the opening and closing of each valve 48.

[0144] When valve 48 is closed, no processing liquid is discharged from the processing tank 25. When valve 48 is opened, the processing liquid is discharged from the processing tank 25 through the liquid discharge line 47 to the waste liquid tank 36. In one embodiment, the control unit 21 switches the opening and closing of each valve 48 based on the operator's operation using an operating device (not shown), such as a user interface. In this case, when the detoxification treatment of by-products is being performed in the processing tank 25, valve 48 is closed. Then, when the detoxification treatment is completed, the control unit 21 opens the valve and discharges the processing liquid from the processing tank 25 based on the operator's operation. Note that the switching of valve 48 opening and closing does not necessarily have to be done by the control unit 21, and in another embodiment, the switching of valve 48 opening and closing may be done by the operator without going through the control unit 21.

[0145] In this embodiment, when the processing liquid is discharged from the processing tank 25, the valve 48 is closed. Then, the valve 42 is opened to supply aqueous solvent to the processing tank 25. The member to be processed 37 is then washed with the aqueous solvent.

[0146] The temperature sensor 50 is positioned to measure the temperature of the processing liquid contained in the processing tank 25. A thermometer can be used instead of the temperature sensor.

[0147] The cooling unit 51 cools the processing liquid contained in the processing tank 25. The cooling unit 51 may be, for example, a blower that cools the processing tank 25 from the outside, or a refrigerant installed adjacent to the outer wall surface of the processing tank 25. Figure 3 shows a block diagram illustrating the temperature control mechanism for the processing liquid in the processing tank 25. When the temperature sensor 50 receives a signal from the control unit 21, it measures the temperature of the processing liquid in the processing tank 25 and inputs the measurement result to the control unit 21 as measured value information. The storage medium of the control unit 21 holds the measured value information. The processor or integrated circuit of the control unit 21 calculates the temperature change amount based on the measured value information. Next, the processor or integrated circuit of the control unit 21 compares the temperature change amount with a reference amount (e.g., +10°C) that is stored in the storage medium beforehand. If the temperature change amount exceeds the reference amount, the control unit 21 instructs the water solvent tank 22 to supply water solvent to the processing tank 25. In addition, if the temperature change amount exceeds the reference amount, the control unit 21 activates the cooling unit 51 instead of, or when giving, the above instruction. On the other hand, if the temperature change amount is less than or equal to the reference amount, the control unit 21 instructs the processing liquid tank 23 to supply processing liquid to the processing tank 25. In another embodiment, instead of the control unit 21, an operator or other person may issue instructions for supplying liquid to the water solvent tank 22 and the processing liquid tank 23, and operate the cooling unit 51.

[0148] The processing method using the above-described processing apparatus 20 safely detoxifies a mixture containing halosilanes and / or hydrolysates of halosilanes in the processing tank 25. In addition, the gas (hydrogen) generated by the reaction between the processing liquid and the mixture is appropriately exhausted by the exhaust mechanism 27. Furthermore, since parameters related to the progress of the reaction between the processing liquid and the mixture in the processing tank 25 are detected by the sensor 28, the progress of the detoxification of the mixture can be appropriately determined based on the detection results from the sensor 28. In parallel with the detoxification of the mixture, the reaction between the mixture and the processing liquid is accelerated by activating one of the dispersion mechanism 31, the stirring mechanism 32, or the liquid circulation mechanism 33, thereby accelerating the detoxification of the mixture.

[0149] Examples of processing methods using the processing apparatus described above will be explained with reference to Figures 4 to 8. Figure 4 is a flowchart showing the first example of the processing method.

[0150] Step 60 begins after a mixture containing halosilanes and / or hydrolysates of halosilanes precipitates as a by-product in the discharge route of an epitaxial growth apparatus or the like, as illustrated in Figure 1. Step 61 supplies a treatment liquid (e.g., chemical solution) from the treatment liquid tank 23 to the treatment tank 25. Step 62 places the member to be treated 37 (e.g., a part with oily silane attached) into the treatment tank 25. This starts the detoxification treatment of by-products attached to the member to be treated 37. Step 63 measures the temperature of the treatment liquid in the treatment tank 25 using the temperature sensor 50. Step 64 compares the measured value with the initial measured value and compares the resulting temperature change with a reference amount (e.g., +10°C). If the temperature change exceeds +10°C (No. in step 64), (a) leave it as is, (b) reduce the base concentration of the treatment solution by supplying aqueous solvent from the aqueous solvent tank 22 to the treatment tank 25, or (c) cool the treatment solution in the treatment tank 25 with the cooling unit 51 (step 65). In step 65, only one of (a) to (c) may be performed, or two or more steps may be combined. For example, the treatment solution in the treatment tank 25 may be cooled with the cooling unit 51 while the base concentration of the treatment solution is reduced. Step 65 is performed until the temperature change falls below +10°C.

[0151] If the temperature change is +10°C or less (Yes in step 64), the pH of the treatment solution in the treatment tank 25 is measured using the pH meter on the sensor 28 (step 66). If the pH of the treatment solution is not basic, for example, if the pH is less than 8 (No in step 67), it is highly likely that the detoxification process has stopped midway due to a lack of basic components. Therefore, treatment solution is supplied from the treatment solution tank 23 to the treatment tank 25 (step 68). After that, the process returns to measuring the temperature of the treatment solution (step 63) in order to continue the detoxification process.

[0152] If the pH of the treatment solution is basic, for example, if the pH is between 8 and 14 (Yes in step 67), check whether there are any untreated parts 37 (for example, parts with oily silane attached) that have not yet been put into the treatment tank 25 (step 69). If, as a result of the check, there are still untreated parts 37 remaining (No in step 69), restart from step 62, in which new parts 37 are put into the treatment tank 25. If the detoxification treatment of by-products is complete (Yes in step 69), leave the parts 37 immersed in the treatment solution for a certain period of time (step 70). After the waiting period, the treatment is finished (step 71).

[0153] According to the first example method described above, when treating a mixture containing one or both halosilanes and hydrolysates of halosilanes by contacting it with a treatment solution having a pH of 8 to 14 and a mass equivalent to 100 times or more the mass of the mixture, the temperature change of the treatment solution during treatment is maintained at 10°C or less, and the pH of the treatment solution is maintained within the range of 8 to 14. By maintaining the temperature change of the treatment solution during treatment at 10°C or less, the treatment can be carried out gently. Furthermore, by maintaining the pH of the treatment solution within the range of 8 to 14, it is possible to avoid the treatment stalling or stopping midway. As a result, the treatment can be carried out smoothly while suppressing the temperature rise, and thus the detoxification treatment can be carried out safely.

[0154] Figure 5 is a flowchart showing a second example of the processing method.

[0155] Step 80 begins after a mixture containing halosilanes and / or hydrolysates of halosilanes precipitates as a by-product in the discharge path of an epitaxial growth apparatus, etc., as illustrated in Figure 1. A treatment liquid (e.g., chemical solution) is supplied from the treatment liquid tank 23 to the treatment tank 25 (Step 81). The treatment liquid in the treatment tank 25 is stirred by either the dispersion mechanism 31, the stirring mechanism 32, or the liquid circulation mechanism 33 (Step 82). While continuing this stirring, the member to be treated 37 (e.g., a part with oily silane attached) is placed in the treatment tank 25 (Step 83). This starts the detoxification treatment of by-products attached to the member to be treated 37. The temperature sensor 50 measures the temperature of the treatment liquid in the treatment tank 25 (Step 84). The control unit 21 compares the measured value with the initial measured value and compares the amount of temperature change obtained from this comparison with a reference amount (e.g., +10°C) (Step 85). If the temperature change exceeds +10°C (No. in step 85), (a) leave it as is, (b) reduce the base concentration of the treatment solution by supplying aqueous solvent from the aqueous solvent tank 22 to the treatment tank 25, or (c) cool the treatment solution in the treatment tank 25 with the cooling unit 51 (step 87). In step 87, only one of (a) to (c) may be performed, or two or more steps may be combined.

[0156] If the temperature change is +10°C or less (Yes in step 85), the pH of the treatment solution in the treatment tank 25 is measured using the pH meter on sensor 28 (step 86). If the pH of the treatment solution is not basic, for example, if the pH is less than 8 (No in step 88), it is highly likely that the detoxification process has stopped midway due to a lack of basic components. Therefore, treatment solution is supplied from the treatment solution tank 23 to the treatment tank 25 (step 90). After that, the process returns to measuring the temperature of the treatment solution (step 84) in order to continue the detoxification process.

[0157] If the pH of the treatment solution is basic, for example, if the pH is between 8 and 14 (Yes in step 88), check whether there are any untreated parts 37 (for example, parts with oily silane attached) that have not yet been put into the treatment tank 25 (step 89). If, as a result of the check, there are still untreated parts 37 remaining (No in step 89), the process restarts from adding new parts 37 to the treatment tank 25 (step 83). If the detoxification of by-products is complete (Yes in step 89), leave the parts 37 immersed in the treatment solution for a certain period of time (step 91). After the period of time, stop stirring the treatment solution (step 92). Then the process is finished (step 93).

[0158] According to the second example method described above, when a mixture containing one or both halosilanes and hydrolysates of halosilanes is brought into contact with a treatment solution having a pH of 8 to 14 and a mass equivalent to 100 times or more the mass of the mixture, the treatment solution is stirred while the treatment solution and the mixture are brought into contact. This promotes the reaction between the mixture and the treatment solution. Furthermore, during the treatment, the temperature change of the treatment solution is maintained at 10°C or less, and the pH of the treatment solution is maintained within the range of 8 to 14. By maintaining the temperature change of the treatment solution at 10°C or less, the treatment can proceed smoothly. Also, by maintaining the pH of the treatment solution within the range of 8 to 14, it is possible to avoid the treatment stalling or stopping midway. As a result, the treatment of unreacted substances can be promoted while suppressing the temperature rise, thus enabling safe detoxification treatment.

[0159] Figure 6 is a flowchart showing a third example of the processing method.

[0160] After a mixture containing halosilanes and / or hydrolysates of halosilanes precipitates as a byproduct in the discharge route of an epitaxial growth apparatus or the like illustrated in Figure 1, the treatment is started (step 100). Water solvent (e.g., water) is supplied from the water solvent tank 22 to the treatment tank 25 (step 101). Instead of water, an aqueous solution to which additives such as surfactants have been added may be used. The member to be treated 37 (e.g., a part with oily silane attached) is placed in the treatment tank 25 (step 102). This starts the hydrolysis treatment of byproducts attached to the member to be treated 37. The temperature of the water solvent in the treatment tank 25 is measured by the temperature sensor 50 (step 103). The control unit 21 compares the measured value with the initial measured value and compares the amount of temperature change obtained from the comparison with a reference amount (e.g., +10°C) (step 104). If the temperature change exceeds +10°C (No. in step 104), (A) leave it as is, (B) increase the amount of water solvent by supplying liquid from the water solvent tank 22 to the treatment tank 25, or (C) cool the water solvent in the treatment tank 25 with the cooling unit 51 (step 106). In step 106, only one of (A) to (C) may be performed, or two or more steps may be combined. Step 106 is performed until the temperature change falls below +10°C.

[0161] If the temperature change is +10°C or less (Yes in step 104), check whether there are any untreated members 37 (e.g., parts with oily silane attached) that have not yet been put into the treatment tank 25 (step 105). If the check reveals that there are still untreated members 37 remaining (No in step 105), the process restarts from step 102, where new members 37 are added to the treatment tank 25. If the hydrolysis treatment of by-products is complete (Yes in step 105), the treatment liquid is supplied from the treatment liquid tank 23 to the treatment tank 25 (step 107). This starts the detoxification treatment of by-products attached to the members 37. The temperature sensor 50 measures the temperature of the treatment liquid in the treatment tank 25 (step 108). The control unit 21 compares the measured value with the initial measured value and compares the resulting temperature change with a reference amount (e.g., +10°C) (step 109). If the temperature change exceeds +10°C (No. in step 109), (a) leave it as is, (b) reduce the base concentration of the treatment solution by supplying aqueous solvent from the aqueous solvent tank 22 to the treatment tank 25, or (c) cool the treatment solution in the treatment tank 25 with the cooling unit 51 (step 111). In step 111, only one of (a) to (c) may be performed, or two or more steps may be combined.

[0162] If the temperature change is +10°C or less (Yes in step 109), the pH of the treatment solution in the treatment tank 25 is measured by the pH meter on the sensor 28 (step 110). If the pH of the treatment solution is not basic, for example, if the pH is less than 8 (No in step 112), it is highly likely that the detoxification process has stopped midway due to a lack of basic components. Therefore, the process returns to step 107, and the treatment solution is supplied from the treatment solution tank 23 to the treatment tank 25 to continue the detoxification process.

[0163] If the pH of the treatment solution is basic, for example, if the pH is between 8 and 14 (Yes in step 112), leave the member to be treated 37 immersed in the treatment solution for a certain period of time (step 113). After that, the treatment is complete (step 114).

[0164] According to the third example method described above, after hydrolysis of halosilanes, the resulting mixture containing the hydrolyzed halosilanes is brought into contact with a treatment solution having a pH of 8 to 14 and a mass equivalent to 100 times or more the mass of the mixture. During the hydrolysis and subsequent detoxification treatments, the temperature change of the treatment solution during the treatment is maintained at 10°C or less, allowing the hydrolysis and detoxification treatments to proceed gently. Furthermore, by maintaining the pH of the treatment solution in the range of 8 to 14 during the detoxification treatment, it is possible to avoid the treatment stalling or stopping midway. As a result, the treatment can proceed smoothly while suppressing temperature rise, thus enabling safe detoxification. Figure 7 is a flowchart showing a fourth example of the processing method.

[0165] Step 120 begins after a mixture containing halosilanes and / or hydrolysates of halosilanes precipitates as a by-product in the discharge route of an epitaxial growth apparatus, etc., as illustrated in Figure 1. A treatment liquid (e.g., chemical solution) is supplied from the treatment liquid tank 23 to the treatment tank 25 (Step 121). The member to be treated 37 (e.g., a part with oily silane attached) is placed in the treatment tank 25 (Step 122). This starts the detoxification treatment of by-products attached to the member to be treated 37. The temperature of the treatment liquid in the treatment tank 25 is measured by the temperature sensor 50 (Step 123). The control unit 21 compares the measured value with the initial measured value and compares the amount of temperature change obtained from this comparison with a reference amount (e.g., +10°C) (Step 124). If the temperature change exceeds +10°C (No. in step 124), (a) leave it as is, (b) reduce the base concentration of the treatment solution by supplying aqueous solvent from the aqueous solvent tank 22 to the treatment tank 25, or (c) cool the treatment solution in the treatment tank 25 with the cooling unit 51 (step 126). In step 126, only one of (a) to (c) may be performed, or two or more steps may be combined. Step 126 is performed until the temperature change falls below +10°C.

[0166] If the temperature change is +10°C or less (Yes in step 124), the pH of the treatment solution in the treatment tank 25 is measured using the pH meter on sensor 28 (step 125). If the pH of the treatment solution is not basic, for example, if the pH is less than 8 (No in step 127), it is highly likely that the detoxification process has stopped midway due to a lack of basic components. Therefore, treatment solution is supplied from the treatment solution tank 23 to the treatment tank 25 (step 129). After that, the process returns to measuring the temperature of the treatment solution (step 123) in order to continue the detoxification process.

[0167] If the pH of the treatment solution is basic, for example, if the pH is between 8 and 14 (Yes in step 127), check whether there are any untreated components 37 (e.g., parts with oily silane attached) that have not yet been put into the treatment tank 25 (step 128). If, as a result of the check, there are still untreated components 37 remaining (No in step 128), start again from adding new components 37 to the treatment tank 25 (step 122). If the detoxification of by-products is complete (Yes in step 128), leave the components 37 immersed in the treatment solution for a certain period of time (step 130). The standing time can be, for example, 1 hour or more, and 10 hours or more is more preferable. After standing, take a sample of the solid immersed in the treatment solution in the treatment tank 25 and check the chemical structure or atomic bonding state of the solid by Raman spectroscopy, infrared spectroscopy, or nuclear magnetic resonance spectroscopy (step 131). If the solid contains halosilanes and hydrolysates of halosilanes (No in step 132), return to the step of maintaining the basicity of the treatment solution (step 127) and continue the detoxification treatment. If halosilanes and hydrolysates of halosilanes are not detected (Yes in step 132), the treatment is terminated (step 133).

[0168] According to the fourth example method described above, the spectral intensity of one of the Raman spectrum, IR spectrum, or NMR spectrum is measured for the treated material treated by the first example method, making it possible to appropriately determine the progress of the detoxification treatment.

[0169] Figure 8 is a flowchart showing a fifth example of the processing method.

[0170] After a mixture containing halosilanes and / or hydrolysates of halosilanes precipitates as a by-product in the discharge route of an epitaxial growth apparatus, etc., as illustrated in Figure 1, the treatment is started (step 140). A treatment liquid (e.g., chemical solution) is supplied from the treatment liquid tank 23 to the treatment tank 25 (step 141). The member to be treated 37 (e.g., a part with oily silane attached) is placed in the treatment tank 25 (step 142). This starts the detoxification treatment of by-products attached to the member to be treated 37. The condition inside the treatment tank 25 is visually checked (step 143). If vigorous foaming is observed inside the treatment tank 25 (No in step 144), it is left to stand until the foaming subsides (step 146). Once the vigorous foaming has subsided (Yes in step 144), it is checked whether there are any untreated members to be treated 37 (e.g., a part with oily silane attached) that have not yet been placed in the treatment tank 25 (step 145). If, upon inspection, it is found that there are still untreated members 37 remaining (No. in step 145), the process restarts from the step of adding new members 37 to the treatment tank 25 (step 142). If the detoxification of by-products is complete (Yes in step 145), the pH of the treatment solution in the treatment tank 25 is measured using the pH meter on the sensor 28 (step 147). If the pH of the treatment solution is not basic, for example, if the pH is less than 8 (No. in step 148), it is highly likely that the detoxification process has stopped midway due to a lack of basic components. Therefore, treatment solution is supplied from the treatment solution tank 23 to the treatment tank 25 (step 150). After that, in order to continue the detoxification process, the process returns to visually checking the condition inside the treatment tank 25 (step 143).

[0171] If the pH of the treatment solution is basic, for example, if the pH is between 8 and 14 (Yes in step 148), leave the workpiece 37 immersed in the treatment solution for a certain period of time (step 149). After this period, the treatment is complete (step 151).

[0172] According to the fifth example method described above, when a mixture containing one or both halosilanes and hydrolysates of halosilanes is brought into contact with a treatment solution having a pH of 8 to 14 and a mass equivalent to 100 times or more the mass of the mixture, the foaming state of the treatment solution is observed. The greater the heat generated by the reaction, the more intense the foaming of the treatment solution. Therefore, by visually observing the foaming state of the treatment solution, the temperature rise of the treatment solution can be estimated in a simple manner. Furthermore, by maintaining the pH of the treatment solution within the range of 8 to 14 during treatment, it is possible to avoid the treatment stalling or stopping midway. As a result, since the temperature rise can be suppressed in a simple manner and the treatment can proceed smoothly, detoxification can be performed in a safe and simple manner. [Examples]

[0173] The following describes some examples.

[0174] <Example 1> First, a raw material gas was introduced into an epitaxial growth apparatus and reacted with a silicon substrate at a temperature of 800°C to form a single-crystal silicon film on the silicon substrate. As the raw material gas, a mixed gas of hydrogen gas, dichlorosilane, and hydrogen chloride was used. The hydrogen concentration in the mixed gas was 95% by volume or higher.

[0175] Next, the piping of the epitaxial growth apparatus was disassembled under a nitrogen atmosphere, and oily silane was collected as a by-product. The by-product was a white, creamy liquid. Subsequently, the collected by-product was analyzed using the method described above, and it was confirmed that it contained chlorosilanes having a cyclic structure that appears to correspond to one of the structural formulas (a) to (d), (1-1), (2-1), (12-1), and (14-1) above.

[0176] Next, 0.05 g of the by-product was weighed into a petri dish in an argon-purged glove box. This petri dish was then placed in an airtight container and moved to a fume hood in the open air. The temperature in the fume hood was 26.4°C and the humidity was 55%.

[0177] Next, a treatment solution was prepared. The treatment solution used was water in which tetramethylammonium hydroxide (TMAH) was dissolved. The concentration of TMAH in the treatment solution was 2.5% by mass.

[0178] Next, a petri dish was removed from the airtight container, and 5 g of the treatment solution was added to it. The by-product and the treatment solution were then reacted in the atmosphere. As a result, fine bubbles were observed from the by-product. This process was carried out while monitoring the temperature of the treatment solution using a thermometer. The mass ratio of the treatment solution to the mass of the by-product was 100 times.

[0179] <Examples 2-4, 6, 8-11, 13> The treatment was carried out in the same manner as in Example 1, except that the base type, base concentration, pH, added mass, and the ratio of added mass to the by-product mass of the treatment solution were changed as shown in Table 1 below.

[0180] <Example 5> First, 0.05 g of the by-product was weighed into a petri dish using the same method as described in Example 1. Next, 5 g of water was added dropwise to the petri dish and allowed to stand for 1 hour. Then, 5 g of the treatment solution was added dropwise to the petri dish. The by-product was treated in this manner. The temperature of the treatment solution was measured in the same manner as in Example 1. The mass ratio of the treatment solution to the mass of the by-product was 100 times.

[0181] The treatment solution used was water in which tetramethylammonium hydroxide (TMAH) was dissolved. The concentration of TMAH in the treatment solution was 2.5% by mass.

[0182] <Examples 7 and 12> The treatment was carried out in the same manner as in Example 5, except that the base type, base concentration, and pH of the treatment solution were changed as shown in Table 1 below.

[0183] <Comparative Examples 1-3, 5-7> The treatment was carried out in the same manner as in Example 1, except that the base type, base concentration, pH, added mass, and the ratio of added mass to the by-product mass of the treatment solution were changed as shown in Table 2 below.

[0184] <Comparative Example 4> The treatment was carried out in the same manner as in Example 5, except that the mass of water added in the hydrolysis reaction, the base concentration of the treatment solution, the added mass, and the ratio of the added mass to the mass of by-products were changed as shown in Table 2 below.

[0185] (pH measurement) The pH of the treatment solution before and after processing the by-product was measured using pH test paper. The results are shown in Tables 1-4.

[0186] (temperature measurement) The temperature of the treatment solution during processing was continuously measured and recorded using a thermometer. The maximum temperature (°C) and the difference between the temperature of the treatment solution before processing and the maximum temperature (°C) are shown in Tables 3 and 4.

[0187] (Friction sensitivity test and flame sensitivity test) The following method was used to determine whether or not flammable solids were present in the treatment solution after processing the by-products.

[0188] Friction sensitivity test First, the processing solution on the petri dish was thoroughly dried in an exhaust booth. Next, small amounts of the remaining solid material on the petri dish were transferred to a resin container and a stainless steel container, respectively. Then, friction sensitivity tests were conducted using both resin and metal. For the friction sensitivity test using resin, a fluororesin spatula was pressed against the solid material on the fluororesin container and moved around on the petri dish. At this time, it was visually confirmed whether or not the solid material ignited. If ignition occurred, it was marked "yes," and if ignition did not occur, it was marked "no." The results of the friction sensitivity test (resin) are shown in Tables 3 and 4. On the other hand, for the friction sensitivity test using metal, a stainless steel spatula was pressed against the solid material on the stainless steel container and moved around on the petri dish. At this time, it was visually confirmed whether or not the solid material ignited. If ignition occurred, it was marked "yes," and if ignition did not occur, it was marked "no." The results of the friction sensitivity test (metal) are shown in Tables 3 and 4.

[0189] Flame sensitivity test Solid material was placed in a stainless steel container, and a flame was brought into contact with it using a portable ignition device. The presence or absence of ignition was visually confirmed. Butane gas was used in the portable ignition device. The flame temperature was approximately 500°C. The results of the flame sensitivity test are shown in Tables 3 and 4, where ignition was recorded as "yes" and non-ignition as "no".

[0190] [Table 1]

[0191] [Table 2]

[0192] [Table 3]

[0193] [Table 4]

[0194] As is clear from Tables 1 to 4, the treatment methods in Examples 1 to 13 resulted in a temperature change of 10°C or less during treatment, and as a result, the maximum temperature was lower than that of Comparative Examples 1-7. Furthermore, the pH of the treatment solution after treatment was 8 or higher, indicating basicity. In addition, the treatment methods in Examples 1 to 13 did not result in ignition in either the friction sensitivity test or the fire sensitivity test, and no explosive substances were present in the treatment solution after the processing of by-products was completed.

[0195] In contrast, as in Comparative Examples 1-7, even though the treatment solution was basic, when the mass ratio of the treatment solution to the mass of the by-product was less than 100 times, the maximum temperature during treatment was higher than in the examples. Furthermore, when the maximum temperature during treatment was significantly high, as in Comparative Example 2, or when the pH of the treatment solution after treatment was acidic, as in Comparative Example 7, ignition occurred in the fire sensitivity test. From this, it can be seen that the safety of the treatment can be improved by suppressing the temperature rise during treatment or by keeping the treatment solution basic.

[0196] As shown in Examples 2, 3, 4, 8, and 13, when the ratio of the mass of the treatment solution added to the mass of the object to be treated exceeds 100 times, there is almost no temperature rise during treatment, and safety is enhanced.

[0197] A comparison of Example 1 and Example 5 shows that the method of Example 5, which involves hydrolysis of halosilanes followed by detoxification treatment, results in a lower maximum temperature during treatment and a smaller temperature rise. Similar trends can be observed from the comparisons of Example 6 and Example 7, and Example 11 and Example 12.

[0198] Comparing Examples 9 and 10, which use bases with a base dissociation constant Kb greater than 1, it can be seen that Example 9 has a higher maximum temperature. The reason for this is explained below. The magnitude of the temperature rise can be influenced by the amount of heat generated by the reaction, the reaction rate, the heat dissipation rate, and the heat capacity. The amount of heat generated and the heat capacity appear to be almost the same for both Example 9 and Example 10. Since the NaOH in Example 9 has a smaller molecular weight than the Ca(OH)2 in Example 10, if the base concentration of the aqueous solution is the same 10% by mass, the molar concentration of the treatment solution in Example 9 will be higher than that of Example 10. As a result, the hydroxide ion concentration in the treatment solution will be higher in Example 9, which is thought to be why the reaction rate of the treatment is higher, the temperature rise is greater, and the maximum temperature is higher.

[0199] In the above embodiments, the temperature change of the treatment solution during processing was maintained at 10°C or less without dilution or cooling of the treatment solution. As mentioned above, the magnitude of the temperature rise can be influenced by the amount of heat generated by the reaction, the reaction rate, the heat dissipation rate, and the heat capacity. Therefore, if the amount of heat generated increases due to an increase in the mass of the object to be treated, combining the processing methods of the first to fifth embodiments with the above embodiments can reliably suppress the temperature rise during processing, thereby enabling safer detoxification treatment.

[0200] According to at least one embodiment or example described above, a mixture containing one or both halosilanes and hydrolysates of halosilanes is brought into contact with a treatment solution having a pH of 8 to 14 and an amount equivalent to 100 times or more the mass of the mixture. This makes it possible to safely detoxify halosilanes.

[0201] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. The invention described in the original claims of this application is listed below. [1] A method for treating a mixture containing one or both halosilanes and hydrolysates of halosilanes, A treatment method comprising contacting the aforementioned mixture with a treatment solution having a pH of 8 or higher and a pH of 14 or lower, and whose mass is 100 times or more the mass of the aforementioned mixture. [2] The treatment method according to [1], further comprising making the temperature change of the treatment liquid during treatment 10°C or less. [3] The treatment method according to [1] or [2], which includes adjusting the pH of the treatment solution during treatment to a range of 8 to 14. [4] The treatment method according to any one of [1] to [3], wherein the treatment liquid is brought into contact with the mixture while stirring the treatment liquid. [5] The treatment method according to any one of [1] to [4], wherein contact with the mixture is made with the treatment liquid by adding the mixture to the treatment liquid. [6] The treatment method according to any one of [1] to [5], wherein the treatment solution is an aqueous solution containing at least one of an organic base and an inorganic base. [7] The treatment method according to [6], wherein the treatment solution comprises at least one of tetramethylammonium hydroxide and choline hydroxide. [8] The treatment method according to [6], wherein the treatment solution comprises sodium bicarbonate. [Explanation of Symbols]

[0202] 1…Epitaxial growth apparatus, 7…Reaction chamber, 8…Discharge pipe, 11~15,18,19…Piping, 20…Processing device, 21…Control unit, 22…Water solvent tank, 23…Processing liquid tank, 25…Processing tank, 26…Supply mechanism, 27…Exhaust mechanism, 28…Sensor, 31…Dispersion mechanism, 32…Agitation mechanism, 33…Liquid circulation mechanism, 35…Liquid discharge mechanism, 50…Temperature sensor, 51…Cooling unit.

Claims

1. A method for treating a member that contains or is coated with a mixture containing one or both halosilanes and hydrolysates of halosilanes, The member is brought into contact with a treatment solution having a pH of 8 or higher and a pH of 14 or lower, and whose mass is 100 times or more the mass of the mixture, and the temperature change of the treatment solution during the treatment is controlled to 10°C or less. The aforementioned treatment solution is a basic aqueous solution containing at least one of an inorganic base or an organic base. The inorganic base is at least one selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, magnesium hydroxide, ammonium hydroxide, copper hydroxide, iron hydroxide, zinc hydroxide, aluminum hydroxide, elemental metal potassium, elemental metal lithium, elemental metal sodium, sodium carbonate, potassium carbonate, ammonium carbonate, lithium carbonate, barium carbonate, magnesium carbonate, sodium bicarbonate, ammonium bicarbonate, potassium bicarbonate, calcium bicarbonate, calcium oxide, magnesium oxide, and sodium oxide. The treatment method wherein the organic base is at least one selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline hydroxide, butyllithium, methyllithium, butylmagnesium, methylmagnesium, sodium ethoxide, sodium butoxide, potassium ethoxide, potassium butoxide, sodium phenoxide, lithium phenoxide, methylamine, dimethylamine, trimethylamine, triethylamine, ethylenediamine, diethylamine, aniline, pyridine, pyrrolidine, imidazole, and piperidine.

2. The processing method according to claim 1, wherein the control of the amount of temperature change is performed by, when the amount of temperature change exceeds a reference amount, by performing at least one of (a) to (c) of (a) leaving the processing liquid in contact with the member, (b) lowering the base concentration of the processing liquid, or (c) cooling the processing liquid.

3. The treatment method according to claim 1 or claim 2, further comprising adjusting the pH of the treatment solution during treatment to a range of 8 to 14.

4. The processing method according to any one of claims 1 to 3, wherein the processing liquid is brought into contact with the member while the processing liquid is being stirred.

5. The processing method according to any one of claims 1 to 4, wherein contact with the member is made with the processing liquid by immersing the member in the processing liquid.

6. The treatment method according to any one of claims 1 to 5, wherein the concentration of at least one of the organic base and the inorganic base in the treatment solution is 0.01% by mass or more and 30% by mass or less.

7. The treatment method according to claim 1, wherein the treatment solution contains at least one of tetramethylammonium hydroxide and choline hydroxide.

8. The treatment method according to claim 1, wherein the treatment solution contains the sodium bicarbonate.

9. The processing method according to claim 1, wherein the member includes piping.

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