Semiconductor chemical solution and method for producing semiconductor chemical solution

Abstract

The present invention provides a semiconductor chemical solution substantially comprising isopropyl alcohol, wherein the semiconductor chemical solution has a content of t-butyl alcohol of 1,000 ppb by mass or less and a content of ethyl alcohol of 1,000 ppb by mass or less.

Description

Semiconductor chemical solution and method for manufacturing semiconductor chemical solution

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

[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. The semiconductor chemical solution is, for example, isopropyl alcohol.

[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 1,300 to 2,100 parts by mass of water per 100 parts by mass of propylene, and the residence time of water in the reactor is more than 20 minutes and not more than 50 minutes.

[0004] International Publication No. 2017 / 217279

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

[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, if a semiconductor chemical containing t-butyl alcohol is used as an impurity, there is concern that t-butyl alcohol residues may adversely affect semiconductor devices. Because t-butyl alcohol has a melting point of 26°C and is solid at room temperature, it is thought that it is likely to remain as residues.

[0008] An object of the present invention is 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 that allows the contents of t-butyl alcohol and ethyl alcohol to be reduced.

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

[0010] (2) A semiconductor chemical solution, further comprising an alcohol content of 6 carbon atoms of 1 ppb by mass or less.

[0011] (3) A method for producing a semiconductor chemical liquid consisting essentially of isopropyl alcohol, comprising a step of supplying a raw material gas containing propylene, having an isobutene content of 1 volume ppm or less, and an ethylene content of 1 volume ppm 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 gas components in the continuous reactor, which is a 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; and a volume ratio of the discharge amount of the gas components discharged from the continuous reactor to the supply amount of the raw material 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 isopropyl alcohol aqueous solution from the liquid phase and distilling the crude isopropyl alcohol aqueous solution in a high-boiling distillation column.

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

[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 that is capable of reducing the content of t-butyl alcohol and ethyl alcohol.

[0016] 3A to 3C are diagrams illustrating an example of a reaction step in the method for producing a semiconductor chemical solution according to the present embodiment.

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

[0018] [Method for Producing Semiconductor Chemical Solution] The method for producing a semiconductor chemical solution of this embodiment is a method for producing a semiconductor chemical solution 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 solution of this embodiment may further include steps such as a recovery step and a purification step.

[0019] (Feedstock Gas) The feedstock gas contains propylene, and the propylene content is preferably 99% by volume or more, and more preferably 99.9% by volume or more.

[0020] As will be described later, when isobutene and ethylene are hydrated, t-butyl alcohol and ethyl alcohol are produced, respectively, and therefore the contents of isobutene and ethylene in the feedstock gas are preferably low. The content of isobutene in the feedstock 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 feedstock 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 feedstock gas may contain an inert gas such as nitrogen gas, as necessary.

[0021] As will be described later, when an alkene having a carbon number of 6 is disproportionated, isobutene and ethylene may be produced, and therefore the content of the alkene having a carbon number of 6 in the feed gas is preferably as low as possible. The content of the alkene having a carbon number of 6 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 acid catalysts include phosphotungstic acid, silicotungstic acid, and silicomolybdic acid, and two or more of these 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 Step) An example of the reaction step will be described using FIG. 1. When raw material gas and raw material water are supplied to the continuous reactor 1, a gas phase G containing the raw material gas is present in the upper part of the continuous reactor 1, and a liquid phase L containing the raw material water is present in the lower part of the continuous reactor 1. Here, isopropyl alcohol produced in the reaction step is contained in the liquid phase L. Furthermore, when the raw material gas and raw material water are supplied to the continuous reactor 1, gas components are discharged from the gas phase G by repeatedly opening and closing the control valve 2. Therefore, even if a raw material gas with a high propylene purity is used, the time the raw material gas remains in the gas phase G is shortened, thereby suppressing propylene dimerization, and as a result, the contents of t-butyl alcohol, ethyl alcohol, and alcohols having six carbon atoms in the semiconductor chemical solution are reduced.

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

[0025]

[0026] The mass ratio of the raw material gas to the raw material water supplied to the continuous reactor 1 is 0.01 or more and 0.20 or less, preferably 0.02 or more and 0.07 or less, and more preferably 0.03 or more and 0.05 or less. If the mass ratio of the raw material gas to the raw material 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 gas components discharged from the continuous reactor 1 to the supply amount of raw material gas supplied to the continuous reactor 1 is 0.03 or more and 0.30 or less, and preferably 0.11 or more and 0.16 or less. If the ratio of the discharge amount of gas components discharged from the continuous reactor 1 to the supply amount of raw material gas supplied to the continuous reactor 1 is less than 0.03, the contents of t-butyl alcohol, ethyl alcohol, and alcohols 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. As the contents of isobutene and ethylene in the gas components discharged from the continuous reactor 1 increase, the contents of t-butyl alcohol and ethyl alcohol in the semiconductor chemical solution increase. 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. Furthermore, 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 10 minutes or more and 25 minutes or less, and preferably 12 minutes or more and 18 minutes or less. 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 alcohols having 6 carbon atoms in the semiconductor chemical solution increase.

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

[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 alcohols having 6 carbon atoms in the semiconductor chemical solution increase.

[0032] The residence time of the gas components in the continuous reactor 1 can be calculated by the formula: (Volume [L] of the gas phase G of the continuous reactor 1) / (Discharge rate of the gas components [L / min]). The temperature and pressure inside the continuous reactor 1 are high and high, but the discharge rate of the gas components under the temperature and pressure conditions of the continuous reactor 1 can be calculated 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 inside 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. If the temperature inside the continuous reactor 1 is 200° C. or higher, the conversion rate of propylene improves, and if it is 300° C. or lower, the contents of t-butyl alcohol, ethyl alcohol, and alcohol having 6 carbon atoms in the semiconductor chemical liquid 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. 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 the propylene discharged outside the system include propylene discharged from the gas phase G of the continuous reactor 1 via the control valve 2 (see FIG. 1 ), and propylene discharged outside the system from the recovery step and purification step described below without being returned to the reaction step.

[0037] (Recovery step) A liquid component containing isopropyl alcohol and raw water produced in the reaction step is discharged from the liquid phase section L of the continuous reactor 1 and transported to a recovery column. At this time, by setting the temperature and pressure in the recovery column to a predetermined range, propylene dissolved in the water contained in the liquid component is separated, and a crude isopropyl alcohol aqueous solution is recovered. Here, the temperature of the recovery column is preferably 80 ° C. or higher and 200 ° C. or lower, more preferably 100 ° C. or higher and 150 ° C. or lower. The pressure of the recovery column is preferably 100 kPa or higher and 5000 kPa or lower (absolute pressure), 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 conventional isopropyl alcohol production methods, when a raw material gas with a high propylene purity is used, t-butyl alcohol and ethyl alcohol are by-produced. Because 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 process described below. However, according to this embodiment, 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, the amount of t-butyl alcohol and ethyl alcohol by-produced can be reduced. Therefore, 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 even 500 ppb or less, respectively. Furthermore, considering the cost and yield in the reaction process and purification process, 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.

[0040] Furthermore, according to this embodiment, the amount of alcohol having 6 carbon atoms as a by-product can also be reduced. Therefore, the mass ratio of alcohol having 6 carbon atoms to 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, a decrease in the amount of 4-methyl-2-pentanol by-product produced by hydration of 4-methyl-1-pentene leads to a decrease in the amount of t-butyl alcohol and ethyl alcohol by-products. For this reason, 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 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 below.

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

[0042] In the low-boiling distillation column, 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 column, water and compounds with a boiling point higher than that of water are removed, forming an azeotropic mixture of isopropyl alcohol and water. When the dehydration process is performed in the dehydration distillation column, a third component capable of forming an azeotropic mixture with water is added to the dehydration distillation column to form an azeotropic mixture of water and the third component, thereby removing water. The separated water is recovered in a tank and reused as raw water. In the high-boiling distillation column, compounds with a boiling point higher than that of isopropyl alcohol are removed. This allows the content of alcohols with a carbon number of 6 in the semiconductor chemical solution of this embodiment to be reduced to 1 ppb by mass or less, and can also be reduced to 0.1 ppb by mass or less. Particles can be removed by passing the bottoms removed from the high-boiling distillation column through a filter.

[0043] The number of plates in each distillation column and the equivalent number of plates in the distillation column converted into a plate column 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 column and the equivalent number of plates in the distillation column converted into a plate column 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 atmospheric distillation is not particularly limited, but is preferably 0.5 to 50, more preferably 1 to 10. Here, atmospheric pressure refers to a range of 90 kPa to 120 kPa (absolute pressure).

[0044] [Semiconductor Chemical Solution] The semiconductor chemical solution of this embodiment essentially consists of isopropyl alcohol. The content of isopropyl alcohol in the semiconductor chemical solution 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. Because the content of t-butyl alcohol in the semiconductor chemical solution of this embodiment is 1000 mass ppb or less, even when a substrate is cleaned using the semiconductor chemical solution of this embodiment, the influence of t-butyl alcohol residues on the semiconductor device is reduced. Taking into account the cost and yield of the reaction step and the purification step, 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 step and the purification step, 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 alcohol having 6 carbon atoms in the semiconductor chemical solution of this embodiment is preferably 1 mass ppb or less, and more preferably 0.1 mass ppb 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 conventional methods for producing isopropyl alcohol, when a raw material gas with a high purity of propylene is used, in order to separate isopropyl alcohol from an alcohol having a carbon number of 6, the isopropyl alcohol must be dehydrated, for example, until the water content is 100 ppm by mass 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 semiconductor chemicals of this embodiment, the amount of by-produced alcohol having a carbon number of 6 can be reduced, so the content of alcohol having a carbon number of 6 in the semiconductor chemicals 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 mass ppm or more and 100 mass ppm or less, and more preferably 1 mass ppm or more and 20 mass ppm or less.

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

[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, if necessary, the sample was diluted with isopropyl alcohol and then the water content in the sample was measured. The isopropyl alcohol used for dilution had a water content of 100 ppm by mass or less. When the water content in the sample was 100 ppm by mass or less, 5 g or more of the sample was collected with a thermosyringe 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 quantitation for the water content in the sample was 1 ppm by mass.

[0055] (Alcohol Content in a Sample with a Water Content of 10% by Mass or More) Samples were sampled using a GC-MS by the headspace method, and the alcohol content in the sample was measured under the measurement conditions shown below. The lower limit of quantitation for the t-butyl alcohol and ethyl alcohol contents 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 quantitation for the alcohol content with a carbon number of 6 in the standard sample was 100 ppb by mass.

[0056] - Measurement conditions for crude isopropyl alcohol aqueous solution - Apparatus: 7890A / 5975C (Agilent Technologies) Analytical column: J&W DB-1 (60 m x 0.32 mm, 5 μm) Column temperature: 35°C (held for 2 minutes) → Heat at 10°C / min → 250°C (held for 6 minutes) Carrier gas: Helium Injection pressure: 20 psi Linear velocity: 31 cm / sec Injection port temperature: 200°C Sample injection method: Split method Split ratio: 1:5 Injection volume: 1 ml Headspace heating temperature: 60°C Headspace heating time: 20 minutes Transfer line temperature: 240°C Ion source, quadrupole temperatures: 230°C, 150°C Scan ions: m / z = 25 to 250 SIM monitor ions: 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 measurement conditions shown below. The lower limit of quantitation for the t-butyl alcohol and ethyl alcohol contents in the standard sample made of isopropyl alcohol was 10 ppb by mass, respectively. The lower limit of quantitation for the alcohol content with 6 carbon atoms in the standard sample was also 10 ppb by mass.

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

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

[0060] (Concentration Method) Because the sample in this example had a reduced impurity content, the sample to be measured was concentrated as needed to improve the analytical accuracy of compounds with a boiling point higher than that of isopropyl alcohol. The concentration method is described below, but the following procedure was repeated as needed to change the concentration ratio. Using a precision distillation apparatus, the distillation column was distilled for 10 hours at a top temperature of approximately 82°C. The theoretical number of plates in the precision distillation apparatus was 3 to 30, and samples could be concentrated within this range. To prevent sample oxidation, nitrogen was circulated through the precision distillation apparatus in advance to create an inert gas atmosphere. Furthermore, during distillation, nitrogen was also circulated through the reservoir storing the distillate, and the distillation was performed under an inert gas atmosphere. In this example, a standard sample consisting of isopropyl alcohol was concentrated 1000 times, resulting in a lower limit of quantitation of the content of alcohols with a carbon number of 6 in the standard sample of 0.01 ppb by mass.

[0061] [Example 1] (Feedstock gas) The composition of the feedstock gas was analyzed. At this time, standard gases of known concentrations were prepared and quantified. 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 Carbon number 5 alkene (pentene) content: less than 0.1 ppm by volume Carbon number 6 alkene (hexene) content: less than 0.1 ppm by volume The feedstock gas had a density of 1.87 x 10 at standard conditions (101.3 kPa, 0°C). －３ kg / L.

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

[0063] (Reaction step) A continuous reactor having an internal volume of 22.0 L was adjusted so that the volume of the liquid phase present in the lower part of the continuous reactor was 20.0 L and the volume of the gas phase present in the upper part of the continuous reactor was 2.0 L. Furthermore, 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 While being supplied to the continuous reactor at a feed rate of 1.5 L / h (standard state equivalent), 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 is 0.75 kg / L, the residence time of the raw water in the continuous reactor is 20 minutes. In addition, since the discharge rate of the gas components at 280 ° C and 250 atm is 1.6 L / h, the residence time of the gas components in the continuous reactor is 74 minutes.

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

[0065]

[0066]

[0067] (Recovery step) The liquid component was discharged from the liquid phase of the continuous reactor and transported to a recovery column. At this time, the temperature and pressure in the recovery column 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 propylene conversion rate was 95%, and the isopropyl alcohol selectivity was 99.5%. Meanwhile, the separated propylene was recovered in a drum for reuse as a raw material 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]

[0070] (Purification step) The crude isopropyl alcohol aqueous solution was supplied to a low-boiling distillation column to remove low-boiling impurities, and a bottom product was obtained from the bottom of the column. Next, the bottom product was supplied to an azeotropic distillation column 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 column. Next, the azeotropic mixture was supplied to a dehydration distillation column for dehydration, and a bottom product was obtained from the bottom of the column. Next, the bottom product was supplied to a high-boiling distillation column to remove high-boiling impurities, and a distillate was obtained from the top of the column. Here, the number of plates in the high-boiling distillation column 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]

[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 propylene conversion rate 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 equivalent) and the residence time of the gas components in the continuous reactor was changed to 59 minutes (see Table 1). At this time, the propylene conversion rate 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] The feed rate of raw water in the reaction step was changed to 75 kg / h, the residence time of raw water in the continuous reactor was changed to 12 minutes, the discharge rate of gas components in the reaction step was changed to 120 L / h (standard state equivalent), and the residence time of gas components in the continuous reactor was changed to 123 minutes. Except for this, a semiconductor chemical solution was obtained in the same manner as in Example 1 (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] The feed rate of raw water in the reaction step was changed to 75 kg / h, the residence time of raw water in the continuous reactor was changed to 12 minutes, the discharge rate of gas components in the reaction step was changed to 250 L / h (standard state equivalent), and the residence time of gas components in the continuous reactor was changed to 59 minutes. Except for this, a semiconductor chemical solution was obtained in the same manner as in Example 1 (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] The feed rate of raw water in the reaction step was changed to 80 kg / h, the residence time of raw water in the continuous reactor was changed to 11 minutes, the discharge rate of gas components in the reaction step was changed to 500 L / h (standard state equivalent), and the residence time of gas components in the continuous reactor was changed to 30 minutes. Except for this, a semiconductor chemical solution was obtained in the same manner as in Example 1 (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, crude isopropyl alcohol aqueous solution, and semiconductor chemical solution are shown in Tables 2 to 4.

[0078] [Comparative Example 1] The feed rate of raw water and the discharge rate of gas components in the reaction step were changed to 30 kg / h and 80 L / h (volume in the reactor: 0.65 L / h) under standard conditions, respectively, and the residence times of the raw water and gas components in the continuous reactor were changed to 30 minutes and 185 minutes, respectively. Except for this, a semiconductor chemical solution was obtained in the same manner as in Example 1 (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 solution 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 equivalent) and the residence time of the gas components in the continuous reactor was changed to 494 minutes (see Table 1). At this time, the propylene conversion rate 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 propylene conversion rate 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] Table 4 shows that the semiconductor chemicals of Examples 1 to 6 have low contents of t-butyl alcohol, ethyl alcohol, and hexanol. In contrast, the semiconductor chemical of Comparative Example 1 has a high content 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 chemical of Comparative Example 2 has a high content of t-butyl alcohol, ethyl alcohol, and hexanol because the residence time of the gas components in the continuous reactor is 494 minutes and the C / B is 0.02. The semiconductor chemical of Comparative Example 3 has a high content of t-butyl alcohol, ethyl alcohol, and hexanol because the residence time of the raw water in the continuous reactor is 30 minutes.

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

Claims

1. A semiconductor chemical liquid consisting essentially of isopropyl alcohol, wherein 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.

2. The semiconductor chemical solution according to claim 1, further comprising an alcohol content of 6 carbon atoms of 1 ppb by mass or less.

3. A method for producing a semiconductor chemical liquid consisting essentially of isopropyl alcohol, comprising the steps of supplying a raw material gas containing propylene, an isobutene content of 1 volume ppm or less, and an ethylene content of 1 volume ppm 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, 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 material water in the continuous reactor, which is the ratio of the volume [L] of the liquid phase to the supply rate [L / min] of the raw material water supplied to the continuous reactor, is 10 minutes or more and 25 minutes or less, the residence time of the gas component in the continuous reactor, which is the ratio of the volume [L] of the gas phase to the discharge rate [L / min] of the gas component 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.

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

5. The method for manufacturing a semiconductor chemical solution according to claim 3 or 4, wherein the source gas has a propylene content of 99 volume % or more.

6. The method for producing a semiconductor chemical solution according to claim 3 or 4, 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.

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