Semiconductor cleaning chemicals and method for producing semiconductor cleaning chemicals

Abstract

The present invention provides a semiconductor chemical liquid that is substantially composed of isopropyl alcohol, in which the content of t-butyl alcohol is 1000 ppb by mass or less and the content of ethyl alcohol is 1000 ppb by mass or less.

Description

[Technical field]

[0001] The present invention relates to a semiconductor chemical and a method for manufacturing the semiconductor chemical. [Background technology]

[0002] 2. Description of the Related Art In a conventional semiconductor manufacturing process, a substrate such as a semiconductor substrate or a glass substrate is washed with a semiconductor chemical solution, and then dried. For example, isopropyl alcohol is used as the semiconductor chemical solution.

[0003] Patent Document 1 describes a method for producing isopropyl alcohol by direct hydration of propylene. At this time, propylene and water are reacted in a reactor, and the ratio of propylene to water in the reactor is 1300 to 2100 parts by mass per 100 parts by mass of propylene, and the residence time of water in the reactor is more than 20 minutes and 50 minutes or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 217279 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method for producing isopropyl alcohol described in Patent Document 1, when a raw material gas with a high purity of propylene is used, t-butyl alcohol (2-methyl-2-propyl alcohol) and ethyl alcohol are by-produced. For this reason, it is desirable to reduce the content of t-butyl alcohol and ethyl alcohol in the semiconductor chemical solution.

[0006] However, since t-butyl alcohol and ethyl alcohol have a small difference in boiling point from isopropyl alcohol and also form an azeotrope with isopropyl alcohol, it is very difficult to reduce the content of t-butyl alcohol and ethyl alcohol in semiconductor chemicals by distillation.

[0007] Furthermore, when using semiconductor chemicals that contain t-butyl alcohol as an impurity, there is concern that t-butyl alcohol residues may adversely affect semiconductor devices. Since t-butyl alcohol has a melting point of 26°C and is solid at room temperature, it is assumed that it is prone to remain as residues.

[0008] An object of the present invention is to provide a semiconductor chemical liquid having a reduced content of t-butyl alcohol and ethyl alcohol, and a method for producing a semiconductor chemical liquid capable of reducing the content of t-butyl alcohol and ethyl alcohol. [Means for solving the problem]

[0009] (1) A semiconductor chemical solution consisting essentially of isopropyl alcohol, in which the content of t-butyl alcohol is 1000 ppb by mass or less and the content of ethyl alcohol is 1000 ppb by mass or less.

[0010] (2) The semiconductor chemical further comprises an alcohol having 6 carbon atoms in an amount of 1 ppb by mass or less.

[0011] (3) A method for producing a semiconductor chemical solution consisting essentially of isopropyl alcohol, comprising the steps of supplying a raw material gas containing propylene, having an isobutene content of 1 ppm by volume or less, and an ethylene content of 1 ppm by volume or less, and raw material water to a continuous reactor and reacting them, wherein during the reaction, the continuous reactor has a gas phase and a liquid phase, and a gas component is discharged from the gas phase and supplied to the continuous reactor, the mass ratio of the raw material gas to the raw material water being 0.01 or more and 0.20 or less, a residence time of the raw water in the continuous reactor, which is a ratio of the volume [L] of the liquid phase to the supply rate [L / min] of the raw water, is 10 minutes or more and 25 minutes or less; a residence time of the gas components in the continuous reactor, which is a ratio of the volume [L] of the gas phase to the discharge rate [L / min] of the gas components discharged from the continuous reactor, is 10 minutes or more and 150 minutes or less; and a volume ratio of the discharge amount of the gas components discharged from the continuous reactor to the supply amount of the raw gas supplied to the continuous reactor is 0.03 or more and 0.30 or less.

[0012] (4) The method for producing a semiconductor chemical solution according to (3), further comprising the steps of recovering a crude aqueous isopropyl alcohol solution from the liquid phase portion, and distilling the crude aqueous isopropyl alcohol solution in a high boiling distillation column.

[0013] (5) The method for producing a semiconductor chemical solution according to (3) or (4), wherein the source gas has a propylene content of 99 volume % or more.

[0014] (6) The method for producing a semiconductor chemical solution according to any one of (3) to (5), wherein the temperature in the continuous reactor is 200°C or higher and 300°C or lower, and the pressure in the continuous reactor is 150 atm or higher and 280 atm or lower. Effect of the Invention

[0015] According to the present invention, it is possible to provide a semiconductor chemical solution having a reduced content of t-butyl alcohol and ethyl alcohol, and a method for producing a semiconductor chemical solution capable of reducing the content of t-butyl alcohol and ethyl alcohol. [Brief description of the drawings]

[0016] [Figure 1] 4A to 4C are diagrams illustrating an example of a reaction process in the method for producing a semiconductor chemical solution according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] [Method of manufacturing semiconductor chemicals] The method for producing a semiconductor chemical liquid of this embodiment is a method for producing a semiconductor chemical liquid substantially consisting of isopropyl alcohol, and includes a step of supplying a raw material gas and raw material water to a continuous reactor and reacting them (hereinafter, referred to as a reaction step). The method for producing a semiconductor chemical liquid of this embodiment may further include steps such as a recovery step and a purification step.

[0019] (raw gas) The raw material gas contains propylene, and the propylene content is preferably 99 vol % or more, and more preferably 99.9 vol % or more.

[0020] As described later, when isobutene and ethylene are hydrated, t-butyl alcohol and ethyl alcohol are produced, respectively, so the content of isobutene and ethylene in the raw material gas is preferably small. The content of isobutene in the raw material gas is 1 ppm by volume or less, preferably 0.5 ppm by volume or less, and more preferably 0.1 ppm by volume or less. The content of ethylene in the raw material gas is 1 ppm by volume or less, preferably 0.5 ppm by volume or less, and more preferably 0.1 ppm by volume or less. The raw material gas may contain an inert gas such as nitrogen gas, if necessary.

[0021] As described later, when an alkene having 6 carbon atoms is disproportionated, isobutene and ethylene may be produced, and therefore the content of the alkene having 6 carbon atoms in the feed gas is preferably low. The content of the alkene having 6 carbon atoms in the feed gas is preferably 1 ppm by volume or less, more preferably 0.5 ppm by volume or less, and even more preferably 0.1 ppm by volume or less.

[0022] (raw water) The raw water contains water, but preferably further contains an acid catalyst. Examples of the acid catalyst include phosphotungstic acid, silicotungstic acid, and silicomolybdic acid, and two or more of them may be used in combination. When the raw water contains an acid catalyst, the pH of the raw water at 25°C is preferably 2.5 or more and 4.5 or less. When the pH of the raw water at 25°C is 2.5 or more and 4.5 or less, the conversion rate of propylene and the selectivity of isopropyl alcohol are improved.

[0023] (Reaction process) An example of the reaction process will be described with reference to FIG. 1. When raw gas and raw water are supplied to the continuous reactor 1, a gas phase G containing the raw gas is present at the top of the continuous reactor 1, and a liquid phase L containing the raw water is present at the bottom of the continuous reactor 1. Here, isopropyl alcohol generated in the reaction process is contained in the liquid phase L. In addition, when the raw gas and raw water are supplied to the continuous reactor 1, the gas components are discharged from the gas phase G by repeatedly opening and closing the control valve 2. Therefore, even if a raw gas with a high purity of propylene is used, the time that the raw gas stays in the gas phase G is shortened, so that the dimerization of propylene is suppressed, and as a result, the content of t-butyl alcohol, ethyl alcohol, and alcohol with 6 carbon atoms in the semiconductor chemical solution is reduced.

[0024] The reason for this is not clear, but the following reasons are presumed. When using a raw material gas with a high propylene purity, if gas components are not discharged from the top of the continuous reactor 1, propylene dimerizes, and alkenes with six carbon atoms, such as 4-methyl-1-pentene, tend to be produced. As a result, the alkenes with six carbon atoms are disproportionated to produce isobutene and ethylene, which are then hydrated to produce t-butyl alcohol and ethyl alcohol (see reaction mechanism below). When the alkenes with six carbon atoms that were not disproportionated are hydrated, alcohols with six carbon atoms, such as 4-methyl-2-pentyl alcohol, are produced.

[0025] [ka]

[0026] The mass ratio of the raw gas to the raw water supplied to the continuous reactor 1 is 0.01 to 0.20, preferably 0.02 to 0.07, and more preferably 0.03 to 0.05. If the mass ratio of the raw gas to the raw water supplied to the continuous reactor 1 is less than 0.01, the productivity of the semiconductor chemicals decreases, and if it exceeds 0.20, the contents of t-butyl alcohol, ethyl alcohol, and alcohols having 6 carbon atoms in the semiconductor chemicals increase.

[0027] The volume ratio of the discharge amount of the gas components discharged from the continuous reactor 1 to the supply amount of the raw material gas supplied to the continuous reactor 1 is 0.03 to 0.30, and preferably 0.11 to 0.16. If the ratio of the discharge amount of the gas components discharged from the continuous reactor 1 to the supply amount of the raw material gas supplied to the continuous reactor 1 is less than 0.03, the contents of t-butyl alcohol, ethyl alcohol, and alcohol having 6 carbon atoms in the semiconductor chemical solution will increase, and if it exceeds 0.30, the conversion rate of propylene will decrease.

[0028] Here, the gas components discharged from the continuous reactor 1 include water contained in the raw water, propylene contained in the raw gas, impurities contained in the raw gas (e.g., propane), main products (isopropyl alcohol), by-products (e.g., hexene, isobutene, ethylene), etc. Hexene includes 4-methyl-1-pentene, which may be disproportionated to isobutene and ethylene. When the content of isobutene and ethylene in the gas components discharged from the continuous reactor 1 increases, the content of t-butyl alcohol and ethyl alcohol in the semiconductor chemical solution increases. For this reason, the content of isobutene in the gas components discharged from the continuous reactor 1 is preferably 0.1 ppm by volume or more and 20 ppm by volume or less, more preferably 1 ppm by volume or more and 8 ppm by volume or less. In addition, the content of ethylene in the gas components discharged from the continuous reactor 1 is preferably 0.1 ppm by volume or more and 20 ppm by volume or less, more preferably 1 ppm by volume or more and 5 ppm by volume or less.

[0029] The residence time of the raw water in the continuous reactor 1 is from 10 to 25 minutes, and preferably from 12 to 18 minutes. If the residence time of the raw water in the continuous reactor 1 is less than 10 minutes, the conversion rate of propylene decreases, and if it exceeds 25 minutes, the contents of t-butyl alcohol, ethyl alcohol, and alcohol with 6 carbon atoms in the semiconductor chemical solution increase.

[0030] The residence time of the raw water in the continuous reactor 1 is expressed by the formula: (Volume of the liquid phase L of the continuous reactor 1 [L]) / (Feed rate of raw water [L / min]) It is calculated by:

[0031] The residence time of the gas components in the continuous reactor 1 is 10 minutes or more and 150 minutes or less, and preferably 30 minutes or more and 100 minutes or less. If the residence time of the gas components in the continuous reactor 1 is less than 10 minutes, the conversion rate of propylene decreases, and if it exceeds 150 minutes, the contents of t-butyl alcohol, ethyl alcohol, and alcohol with 6 carbon atoms in the semiconductor chemical solution increase.

[0032] The residence time of the gas components in the continuous reactor 1 is expressed by the formula (Volume of gas phase G of continuous reactor 1 [L]) / (Discharge rate of gas components [L / min]) The inside of the continuous reactor 1 is at high temperature and pressure, but the discharge rate of the gas components under the temperature and pressure conditions of the continuous reactor 1 can be obtained by adjusting the temperature and pressure of the gas components discharged from the continuous reactor 1 to 25°C and 101 kPa (absolute pressure), respectively, and then analyzing the liquid phase and gas phase.

[0033] The temperature in the continuous reactor 1 is preferably 200° C. or higher and 300° C. or lower, and more preferably 250° C. or higher and 280° C. or lower. When the temperature in the continuous reactor 1 is 200° C. or higher, the conversion rate of propylene is improved, and when it is 300° C. or lower, the contents of t-butyl alcohol, ethyl alcohol, and alcohol having 6 carbon atoms in the semiconductor chemical solution are reduced.

[0034] The pressure in the continuous reactor 1 is preferably 150 atm or more and 280 atm or less, and more preferably 200 atm or more and 255 atm or less. When the pressure in the continuous reactor 1 is 150 atm or more, the conversion rate of propylene is improved, and when it is 280 atm or less, the contents of t-butyl alcohol, ethyl alcohol, and alcohol having 6 carbon atoms in the semiconductor chemical solution are reduced.

[0035] The propylene conversion is preferably 85% or more and 97% or less, more preferably 92% or more and 95% or less, and the selectivity of isopropyl alcohol is preferably 99% or more and 99.9% or less, more preferably 99.5% or more and 99.8% or less.

[0036] The conversion rate of propylene is determined from the amount of propylene supplied to the continuous reactor 1 and the amount of propylene discharged outside the system. Examples of propylene discharged outside the system include propylene discharged from the gas phase section G of the continuous reactor 1 via the control valve 2 (see FIG. 1), and propylene discharged outside the system from the recovery process and purification process described below without being returned to the reaction process.

[0037] (Recovery process) Liquid components including isopropyl alcohol and raw water produced in the reaction step are discharged from the liquid phase L of the continuous reactor 1 and transported to the recovery tower. At this time, the temperature and pressure in the recovery tower are set to respective predetermined ranges, so that propylene dissolved in the water contained in the liquid components is separated and a crude isopropyl alcohol aqueous solution is recovered. Here, the temperature of the recovery tower is preferably 80°C or higher and 200°C or lower, and more preferably 100°C or higher and 150°C or lower. In addition, the pressure of the recovery tower is preferably 100 kPa or higher and 5000 kPa or lower (absolute pressure), and more preferably 500 kPa or higher and 2000 kPa or lower (absolute pressure).

[0038] The separated propylene is collected in a drum and reused as a raw material gas. The content of isopropyl alcohol in the crude isopropyl alcohol aqueous solution is preferably 1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 8% by mass or less.

[0039] As described above, in the conventional method for producing isopropyl alcohol, when a raw material gas with a high purity of propylene is used, t-butyl alcohol and ethyl alcohol are by-produced. Since t-butyl alcohol and ethyl alcohol have a small difference in boiling point from isopropyl alcohol and form an azeotrope with isopropyl alcohol, it is very difficult to separate them by distillation in the purification step described later. However, according to this embodiment, the amount of t-butyl alcohol and ethyl alcohol by-produced can be reduced by controlling the residence time of the raw water in the continuous reactor 1 and the residence time of the gas components in the continuous reactor 1. For this reason, the mass ratios of t-butyl alcohol and ethyl alcohol to isopropyl alcohol in the crude isopropyl alcohol aqueous solution can be set to 1000 ppb or less, and can also be set to 500 ppb or less. In addition, the mass ratios of t-butyl alcohol and ethyl alcohol to isopropyl alcohol in the crude isopropyl alcohol aqueous solution are preferably 10 ppb or more, more preferably 100 ppb or more, and even more preferably 200 ppb or more, respectively, in consideration of the cost and yield in the reaction step and the purification step.

[0040] In addition, according to this embodiment, the amount of alcohol having 6 carbon atoms produced as a by-product can be reduced. Therefore, the mass ratio of the alcohol having 6 carbon atoms to the isopropyl alcohol in the crude isopropyl alcohol aqueous solution can be set to 200 ppb or more and 10,000 ppb or less, and can also be set to 2,000 ppb or more and 5,000 ppb or less. In particular, when the amount of 4-methyl-2-pentanol produced as a by-product by hydration of 4-methyl-1-pentene decreases, the amount of t-butyl alcohol and ethyl alcohol produced as by-products decreases. Therefore, the mass ratio of 4-methyl-2-pentanol to isopropyl alcohol in the crude isopropyl alcohol aqueous solution is preferably 1,000 ppb or more and 5,000 ppb or less, and more preferably 1,000 ppb or more and 3,000 ppb or less. The content of the alcohol having 6 carbon atoms in the semiconductor chemical solution of this embodiment can be further reduced by distilling the crude isopropyl alcohol aqueous solution in a high boiling distillation column in the purification step described later.

[0041] (purification process) The crude isopropyl alcohol aqueous solution recovered in the recovery tower is discharged and purified. For example, the crude isopropyl alcohol aqueous solution is purified by a distillation step in a low boiling distillation tower, a distillation step in an azeotropic distillation tower, a dehydration step, and a distillation step in a high boiling distillation tower.

[0042] In the low boiling distillation tower, compounds with a boiling point lower than that of isopropyl alcohol are removed. Examples of compounds with a boiling point lower than that of isopropyl alcohol include ethylene, propylene, acetone, diisopropyl ether, acetaldehyde, and propionaldehyde. In the azeotropic distillation tower, water and compounds with a boiling point higher than that of water are removed, and an azeotropic mixture of isopropyl alcohol and water is formed. When the dehydration step is carried out in the dehydration distillation tower, a third component capable of forming an azeotropic mixture with water is added to the dehydration distillation tower to form an azeotropic mixture of water and the third component, thereby removing water. The separated water is collected in a tank and reused as raw water. In the high boiling distillation tower, compounds with a boiling point higher than that of isopropyl alcohol are removed. As a result, the content of alcohol with a carbon number of 6 in the semiconductor chemical solution of this embodiment can be reduced to 1 mass ppb or less, and can also be reduced to 0.1 mass ppb or less. Particles can be removed by passing the bottoms taken out of the high boiling distillation tower through a filter.

[0043] The number of plates in each distillation tower and the equivalent number of plates in the distillation tower converted into a plate tower are not particularly limited, but are preferably 5 to 320, more preferably 10 to 300. In particular, the number of plates in the high boiling distillation tower and the equivalent number of plates in the distillation tower converted into a plate tower are preferably 5 to 20. This allows the content of alcohols having a carbon number of 6 in the semiconductor chemical solution of this embodiment to be reduced. In addition, the reflux ratio in the normal pressure distillation is not particularly limited, but is preferably 0.5 to 50, more preferably 1 to 10. Here, normal pressure refers to a range of 90 kPa to 120 kPa (absolute pressure).

[0044] [Semiconductor chemicals] The semiconductor chemical liquid of this embodiment is substantially composed of isopropyl alcohol. The content of isopropyl alcohol in the semiconductor chemical liquid of this embodiment is preferably 99.99 mass % or more, and more preferably 99.999 mass % or more.

[0045] The content of t-butyl alcohol in the semiconductor chemical solution of this embodiment is 1000 mass ppb or less, and more preferably 500 mass ppb or less. Since the content of t-butyl alcohol in the semiconductor chemical solution of this embodiment is 1000 mass ppb or less, even if the semiconductor chemical solution of this embodiment is used to clean a substrate, the influence of t-butyl alcohol residues on a semiconductor device is reduced. In consideration of the cost and yield of the reaction process and the purification process, the content of t-butyl alcohol in the semiconductor chemical solution of this embodiment is preferably 10 mass ppb or more, more preferably 100 mass ppb or more, and even more preferably 200 mass ppb or more.

[0046] The content of ethyl alcohol in the semiconductor chemical solution of this embodiment is 1000 mass ppb or less, and more preferably 500 mass ppb or less. In consideration of the cost and yield of the reaction process and the purification process, the content of ethyl alcohol in the semiconductor chemical solution of this embodiment is preferably 10 mass ppb or more, more preferably 100 mass ppb or more, and even more preferably 200 mass ppb or more.

[0047] The isopropyl alcohol contained in the semiconductor chemical solution of this embodiment can be produced by the method for producing the semiconductor chemical solution of this embodiment.

[0048] The content of the alcohol having 6 carbon atoms in the semiconductor chemical liquid of this embodiment is preferably 1 ppb by mass or less, and more preferably 0.1 ppb by mass or less.

[0049] Examples of alcohols having 6 carbon atoms include saturated aliphatic alcohols such as 1-hexyl alcohol, 2-hexyl alcohol, 3-hexyl alcohol, 2-methyl-1-pentyl alcohol, 2-methyl-2-pentyl alcohol, 2-methyl-3-pentyl alcohol, 4-methyl-1-pentyl alcohol, 4-methyl-2-pentyl alcohol, 3-methyl-1-pentyl alcohol, 3-methyl-3-pentyl alcohol, 2,3-dimethyl-1-butyl alcohol, and 2-ethyl-1-butyl alcohol.

[0050] In the conventional method for producing isopropyl alcohol, when a raw material gas with a high purity of propylene is used, in order to separate isopropyl alcohol from alcohol having a carbon number of 6, the isopropyl alcohol must be dehydrated, for example, until the water content is 100 mass ppm or less, and then distilled at a high reflux ratio using a distillation column with a large number of stages. On the other hand, in the method for producing a semiconductor chemical solution of this embodiment, the amount of by-product alcohol having a carbon number of 6 can be reduced, so that the content of alcohol having a carbon number of 6 in the semiconductor chemical solution of this embodiment can be reduced at low cost.

[0051] The water content in the semiconductor chemical solution of this embodiment is preferably 0.1 ppm by mass or more and 100 ppm by mass or less, and more preferably 1 ppm by mass or more and 20 ppm by mass or less.

[0052] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and the above embodiment may be modified as appropriate within the scope of the spirit of the present invention. EXAMPLES

[0053] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0054] [Measurement method] (Water content) The water content in the sample was measured using a trace moisture analyzer CA-200 (manufactured by Mitsubishi Chemical Analytical). At this time, the sample was diluted with isopropyl alcohol as necessary, and then the water content in the sample was measured. The isopropyl alcohol used for dilution had a water content of 100 mass ppm or less. When the water content in the sample was 100 mass ppm or less, 5 g or more of the sample was collected with a thermo syringe in a glove box with a dew point of -60°C or less, and the water content in the sample was measured. The lower limit of quantification of the water content in the sample was 1 mass ppm.

[0055] (Alcohol content when the water content in the sample is 10% by mass or more) Using GC-MS, samples were sampled by the headspace method, and the alcohol content in the sample was measured under the measurement conditions shown below. The lower limit of quantification for the content of t-butyl alcohol and ethyl alcohol in a standard sample consisting of water (95% by mass) and isopropyl alcohol (5% by mass) was 5 ppb by mass, respectively. The lower limit of quantification for the content of alcohol with 6 carbon atoms in the standard sample was 100 ppb by mass.

[0056] -Measurement conditions for crude isopropyl alcohol aqueous solution- Equipment: 7890A / 5975C (Agilent Technologies) Analytical column: J&W DB-1 (60m x 0.32mm, 5μm) Column temperature: 35°C (held for 2 minutes) → 10°C / min heating → 250°C (held for 6 minutes) Carrier gas: Helium Injection pressure: 20psi Linear speed: 31cm / sec Inlet temperature: 200℃ Sample injection method: Split method Split ratio: 1:5 Injection amount: 1ml Headspace heating temperature: 60℃ Headspace heating time: 20 minutes Transfer line temperature: 240℃ Ion source and quadrupole temperatures: 230℃, 150℃ Scan ion: m / z=25~250 SIM monitor ion: 31, 59

[0057] (Alcohol content when the water content in the sample is 10% by mass or less) The alcohol content in the sample was measured using GC-MS under the following measurement conditions. The lower limit of quantification for the content of t-butyl alcohol and ethyl alcohol in the standard sample made of isopropyl alcohol was 10 mass ppb, respectively. The lower limit of quantification for the content of alcohol with 6 carbon atoms in the standard sample was also 10 mass ppb.

[0058] -Measuring conditions for semiconductor chemicals- Equipment: 7890A / 5975C (Agilent Technologies) Analytical column: J&W DB-1 (60m x 0.32mm, 5μm) Column temperature: 35°C (held for 2 minutes) → 10°C / min heating → 250°C (held for 6 minutes) Carrier gas: Helium Injection pressure: 20psi Linear speed: 31cm / sec Inlet temperature: 200℃ Sample injection method: Splitless method Injection volume: 2μl Headspace heating temperature: 60℃ Headspace heating time: 20 minutes Transfer line temperature: 240℃ Ion source and quadrupole temperatures: 230℃, 150℃ Scan ion: m / z=25~250 SIM monitor ion: 31, 59

[0059] -Measurement conditions for source gas and gas components- Equipment: 7890A / 5975C (Agilent Technologies) Analytical column: TC-BOND Alumina / Na2SO4 (30m x 0.25mm, 4μm) Column temperature: 35°C (held for 2 minutes) → 10°C / min heating → 200°C (held for 6 minutes) Carrier gas: Helium Injection pressure: 18psi Linear speed: 52cm / sec Inlet temperature: 150℃ Sample injection method: Split method Split ratio: 1:5 Injection amount: 1ml Headspace heating temperature: 60℃ Headspace heating time: 20 minutes Transfer line temperature: 240℃ Ion source and quadrupole temperatures: 230℃, 150℃ Scan ion: m / z=25~150

[0060] (Concentration method) In the sample of this embodiment, the content of impurities is reduced, so that the sample to be measured is concentrated as necessary to improve the analytical accuracy of compounds having a boiling point higher than that of isopropyl alcohol. The concentration method is shown below, but the following operation is repeated as necessary to change the concentration ratio. In the precision distillation apparatus, the temperature of the top of the distillation tower is set to about 82°C, and distillation is performed for 10 hours. The theoretical number of plates of the precision distillation apparatus is 3 to 30, and the sample can be concentrated within this range. In addition, in order to prevent oxidation of the sample, nitrogen was circulated in advance in the precision distillation apparatus to create an inert gas atmosphere. Furthermore, during distillation, nitrogen was also circulated in the liquid pool that stores the distillate, and distillation was performed under an inert gas atmosphere. In this embodiment, as a result of concentrating a standard sample made of isopropyl alcohol 1000 times, the lower limit of quantification of the content of alcohol with a carbon number of 6 in the standard sample was 0.01 mass ppb.

[0061] [Example 1] (raw gas) The composition of the raw gas was analyzed by preparing standard gases of known concentrations and quantifying them. Propylene content: 99% by volume or more Propane content: 1000 ppm by volume Methane content: less than 0.1 ppm by volume Ethane content: less than 0.1 ppm by volume Ethylene content: less than 0.1 ppm by volume Cyclopropane content: 1 ppm by volume 1-Butene content: less than 0.1 ppm by volume Isobutene content: less than 0.1 ppm by volume Content of alkene (pentene) with 5 carbon atoms: less than 0.1 ppm by volume Content of alkene (hexene) with 6 carbon atoms: less than 0.1 ppm by volume The density of the raw gas at standard conditions (101.3 kPa, 0°C) is 1.87×10 -3 The mean concentration was 1.2 kg / L.

[0062] (raw water) Raw material water was obtained by adding phosphotungstic acid to water so that the pH at 25°C was 3.0.

[0063] (Reaction process) The continuous reactor with an internal volume of 22.0 L was adjusted so that the volume of the liquid phase present at the lower part of the continuous reactor was 20.0 L and the volume of the gas phase present at the upper part of the continuous reactor was 2.0 L. In addition, raw material water heated to 110°C was supplied to the continuous reactor at a supply rate of 45 kg / h, and raw material gas was supplied at a rate of 3 kg / h, i.e., 1.87×10 3 The raw water was fed to the continuous reactor at a feed rate of 1.0 L / h (standard state equivalent), while the gas components were discharged from the gas phase of the continuous reactor at a discharge rate of 200 L / h (standard state equivalent). At this time, the temperature and pressure in the continuous reactor were set to 280°C and 250 atm, respectively, and propylene and water were reacted to produce isopropyl alcohol. Here, since the density of the raw water at 280°C and 250 atm was 0.75 kg / L, the residence time of the raw water in the continuous reactor was 20 minutes. In addition, since the discharge rate of the gas components at 280°C and 250 atm was 1.6 L / h, the residence time of the gas components in the continuous reactor was 74 minutes.

[0064] The reaction conditions in the reaction step are shown in Table 1. The composition of the gas components (volume basis) is shown in Table 2. Here, hexenes refer to hexenes other than 4-methyl-1-pentene.

[0065] [Table 1]

[0066] [Table 2]

[0067] (Recovery process) The liquid component was discharged from the liquid phase of the continuous reactor and transported to a recovery tower. At this time, the temperature and pressure in the recovery tower were set to 140°C and 18 atm, respectively, to separate the propylene dissolved in the water contained in the liquid component, and a crude isopropyl alcohol aqueous solution was obtained. At this time, the conversion rate of propylene was 95%, and the selectivity of isopropyl alcohol was 99.5%. Meanwhile, the separated propylene was collected in a drum to be reused as a raw gas.

[0068] The composition (by mass) of the crude isopropyl alcohol aqueous solution is shown in Table 3. Here, hexanols refer to hexanols other than 4-methyl-2-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-3-pentanol, 3-methyl-1-pentanol, 2,3-dimethyl-2-butanol, and 4-methyl-1-pentanol.

[0069] [Table 3]

[0070] (purification process) The crude isopropyl alcohol aqueous solution was fed to a low boiling distillation tower to remove low boiling impurities, and a bottom liquid was obtained from the bottom of the tower. Next, the bottom liquid was fed to an azeotropic distillation tower to remove high boiling impurities, and an azeotropic mixture of isopropyl alcohol and water (mass ratio 87.5:12.5) was obtained from the top of the tower. Next, the azeotropic mixture was fed to a dehydration distillation tower to be dehydrated, and a bottom liquid was obtained from the bottom of the tower. Next, the bottom liquid was fed to a high boiling distillation tower to remove high boiling impurities, and a distillate was obtained from the top of the tower. Here, the number of stages of the high boiling distillation tower was 15. Next, the distillate was passed through a fluororesin filter with a pore size of 10 nm to obtain a semiconductor chemical solution.

[0071] The composition (by mass) of the semiconductor chemical solution is shown in Table 4. Here, hexanol means an alcohol having six carbon atoms.

[0072] [Table 4]

[0073] [Example 2] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the feed rate of the raw water in the reaction step was changed to 60 kg / h and the residence time of the raw water in the continuous reactor was changed to 15 minutes (see Table 1). At this time, the conversion rate of propylene was 95%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0074] [Example 3] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the discharge rate of the gas components in the reaction step was changed to 250 L / h (standard state conversion) and the residence time of the gas components in the continuous reactor was changed to 59 minutes (see Table 1). At this time, the conversion rate of propylene was 94%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0075] [Example 4] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the feed rate of the raw water in the reaction process was changed to 75 kg / h, the residence time of the raw water in the continuous reactor was changed to 12 minutes, the discharge rate of the gas components in the reaction process was changed to 120 L / h (standard state conversion), and the residence time of the gas components in the continuous reactor was changed to 123 minutes (see Table 1). At this time, the conversion rate of propylene was 97%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0076] [Example 5] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the feed rate of the raw water in the reaction process was changed to 75 kg / h, the residence time of the raw water in the continuous reactor was changed to 12 minutes, the discharge rate of the gas components in the reaction process was changed to 250 L / h (standard state conversion), and the residence time of the gas components in the continuous reactor was changed to 59 minutes (see Table 1). At this time, the conversion rate of propylene was 94%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0077] [Example 6] A semiconductor liquid chemical was obtained in the same manner as in Example 1, except that the feed rate of the raw water in the reaction process was changed to 80 kg / h, the residence time of the raw water in the continuous reactor was changed to 11 minutes, the discharge rate of the gas components in the reaction process was changed to 500 L / h (standard state conversion), and the residence time of the gas components in the continuous reactor was changed to 30 minutes (see Table 1). At this time, the conversion rate of propylene was 88%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, the crude isopropyl alcohol aqueous solution, and the semiconductor liquid chemical are shown in Tables 2 to 4.

[0078] [Comparative Example 1] The feed rate of the raw water and the discharge rate of the gas components in the reaction step were changed to 30 kg / h and 80 L / h (volume in the reactor: 0.65 L / h) in terms of standard conditions, respectively, and the residence time of the raw water and the gas components in the continuous reactor was changed to 30 minutes and 185 minutes, respectively, but the same procedure as in Example 1 was followed to obtain a semiconductor chemical (see Table 1). At this time, the conversion rate of propylene was 98%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical are shown in Tables 2 to 4.

[0079] [Comparative Example 2] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the discharge rate of the gas components in the reaction step was changed to 30 L / h (standard state conversion) and the residence time of the gas components in the continuous reactor was changed to 494 minutes (see Table 1). At this time, the conversion rate of propylene was 99%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0080] [Comparative Example 3] A semiconductor chemical solution was obtained in the same manner as in Example 1, except that the feed rate of the raw water in the reaction step was changed to 30 kg / h and the residence time of the raw water in the continuous reactor was changed to 30 minutes (see Table 1). At this time, the conversion rate of propylene was 95%, and the selectivity of isopropyl alcohol was 99.5%. The compositions of the gas components, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0081] From Table 4, it can be seen that the semiconductor chemicals of Examples 1 to 6 have low contents of t-butyl alcohol, ethyl alcohol, and hexanol. In contrast, the semiconductor chemicals of Comparative Example 1 have high contents of t-butyl alcohol, ethyl alcohol, and hexanol because the residence times of the raw water and gas components in the continuous reactor are 30 minutes and 185 minutes, respectively. The semiconductor chemicals of Comparative Example 2 have high contents of t-butyl alcohol, ethyl alcohol, and hexanol because the residence time of the gas components in the continuous reactor is 494 minutes and C / B is 0.02. The semiconductor chemicals of Comparative Example 3 have high contents of t-butyl alcohol, ethyl alcohol, and hexanol because the residence time of the raw water in the continuous reactor is 30 minutes. [Explanation of symbols]

[0082] 1 Continuous reactor 2. Control valve G Gas phase section L Liquid phase

Claims

1. A semiconductor chemical solution consisting essentially of isopropyl alcohol, The content of t-butyl alcohol is 1000 ppb by mass or less, The content of ethyl alcohol is 1000 ppb by mass or less, A semiconductor chemical solution, comprising an alcohol having 6 carbon atoms in an amount of 1 ppb by mass or less.

2. A method for producing a semiconductor chemical solution consisting essentially of isopropyl alcohol, comprising: The method includes a step of supplying a raw material gas containing propylene, having an isobutene content of 1 ppm by volume or less, and an ethylene content of 1 ppm by volume or less, and raw material water to a continuous reactor and reacting them, During the reaction, the continuous reactor has a gas phase portion and a liquid phase portion, and a gas component is discharged from the gas phase portion, The mass ratio of the raw material gas to the raw material water supplied to the continuous reactor is 0.01 or more and 0.20 or less, the residence time of the raw water in the continuous reactor, which is the ratio of the volume [L] of the liquid phase portion to the supply rate [L / min] of the raw water supplied to the continuous reactor, is 10 minutes or more and 25 minutes or less; the residence time of the gas components in the continuous reactor, which is the ratio of the volume [L] of the gas phase portion to the discharge rate [L / min] of the gas components discharged from the continuous reactor, is 10 minutes or more and 150 minutes or less; A method for producing a semiconductor chemical solution, wherein a volume ratio of a discharge amount of a gas component discharged from the continuous reactor to a supply amount of a raw material gas supplied to the continuous reactor is 0.03 or more and 0.30 or less.

3. Recovering a crude isopropyl alcohol aqueous solution from the liquid phase; The method for producing a semiconductor chemical solution according to claim 2, further comprising the step of distilling the crude aqueous isopropyl alcohol solution in a high boiling distillation column.

4. 4. The method for producing a semiconductor chemical solution according to claim 2, wherein the source gas contains propylene at a content of 99% by volume or more.

5. The temperature in the continuous reactor is 200° C. or more and 300° C. or less, The method for producing a semiconductor chemical solution according to claim 2 or 3, wherein a pressure in the continuous reactor is 150 atm or more and 280 atm or less.

Images