3-hydroxy-γ-butyrolactone, (meth)acrylic acid ester, polymer, resist composition, and method for producing substrate having pattern formed thereon

Abstract

To provide a production method of 3-hydroxy-γ-butyrolactone, which can reduce the amount of impurities.SOLUTION: Provided is a production method of 3-hydroxy-γ-butyrolactone, comprising: step (I) of mixing a compound (1) represented by the following formula (1) (X is a halogen atom and R is a protective group for an ester) and an aqueous solution containing an acidic compound and subjecting the compound (1) to a cyclization reaction to obtain an intermediate aqueous solution containing 3-hydroxy-γ-butyrolactone represented by the following formula (2); step (II) of heating the intermediate aqueous solution to remove water from the intermediate aqueous solution; and step (III) of continuing the heating after completion of water removal in step (II).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing 3-hydroxy-γ-butyrolactone, a method for producing a (meth)acrylic acid ester using the same, a method for producing a polymer, a method for producing a resist composition, and a method for producing a substrate having a pattern formed thereon. [Background technology]

[0002] 3-Hydroxy-γ-butyrolactone is useful as a raw material for the monomer of resist polymers used in semiconductor manufacturing. In addition, optically active 3-hydroxy-γ-butyrolactone is useful as an intermediate for pharmaceuticals, agricultural chemicals, etc.

[0003] Patent Documents 1 and 2 describe a method for producing 3-hydroxy-γ-butyrolactone by cyclization of ethyl 4-chloro-3-hydroxybutyrate. Patent Document 3 describes a method for producing 3-hydroxy-γ-butyrolactone using methyl 4-bromo-3-hydroxybutyrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-77759 [Patent Document 2] International Publication No. 2002 / 26725 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-96068 Summary of the Invention [Problem to be solved by the invention]

[0005] 3-hydroxy-γ-butyrolactone produced by the methods described in Patent Documents 1 to 3 usually contains many impurities and is therefore purified by known purification methods such as distillation, column chromatography, etc. However, such purification steps can lead to a decrease in productivity and an increase in production costs. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing 3-hydroxy-γ-butyrolactone, which can reduce the amount of impurities. [Means for solving the problem]

[0006] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have found that the amount of impurities can be reduced by synthesizing 3-hydroxy-γ-butyrolactone by a cyclization reaction and then heating the resulting product under specific conditions.

[0007] The present invention has the following aspects. [1] Step (I): A step of mixing a compound (1) represented by the following general formula (1) with an aqueous solution containing an acidic compound, and subjecting the compound (1) to a cyclization reaction to obtain an intermediate aqueous solution containing 3-hydroxy-γ-butyrolactone represented by the following general formula (2): Step (II): heating the intermediate aqueous solution to remove water from the intermediate aqueous solution; and Step (III): continuing the heating after the removal of water in Step (II) is completed; The method for producing 3-hydroxy-γ-butyrolactone, comprising:

[0008] [ka]

[0009] (In formula (1), X represents a halogen atom, and R represents an ester protecting group.) [2] The method according to [1], wherein in the step (III), the heating is continued for 0.5 to 20 hours. [3] The method according to [1] or [2], wherein in the step (III), the heating is continued until the content of oligomers becomes 20% or less. [4] The method according to any one of [1] to [3], wherein X is a chlorine atom. [5] The method according to any one of [1] to [4], wherein R is a methyl group or an ethyl group. [6] The method according to any one of [1] to [5], wherein the acidic compound is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and formic acid. [7] The method according to any one of [1] to [6], wherein the reaction temperature in the step (I) is 40 to 150°C. [8] The method according to any one of [1] to [7], wherein the heating temperature in the steps (II) and (III) is 30 to 120°C. [9] The method according to any one of [1] to [8], wherein in the step (II) and the step (III), the heating is carried out under a reduced pressure of 500 Torr or less.

[10] A method for producing a (meth)acrylic acid ester, comprising producing 3-hydroxy-γ-butyrolactone by the production method according to any one of the above [1] to [9], and reacting the resulting 3-hydroxy-γ-butyrolactone with (meth)acrylic anhydride to produce a (meth)acrylic acid ester (5) represented by the following formula (5):

[0010] [ka]

[0011] (In formula (5), Y represents a hydrogen atom or a methyl group.)

[11] A method for producing a polymer, comprising producing the (meth)acrylic acid ester (5) by the method according to

[10] above, and polymerizing a monomer containing the (meth)acrylic acid ester (5) thus obtained to produce a polymer.

[12] The method for producing a polymer according to

[11] , wherein the polymer is a polymer for lithography.

[13] A method for producing a resist composition, comprising producing a polymer for lithography by the production method according to

[12] above, and using the resulting polymer for lithography to produce a resist composition.

[14] A method for producing a substrate having a pattern formed thereon, the method comprising: producing a resist composition by the production method according to

[13] above; applying the resist composition thus obtained onto a substrate to form a resist film; exposing the resist film to light; and developing the exposed resist film using a developer. [Effects of the Invention]

[0012] According to the present invention, the amount of impurities in the production of 3-hydroxy-γ-butyrolactone can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with various modifications within the scope of the gist thereof. As used herein, "(meth)acrylic" means acrylic, methacrylic, or both. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0014] <Method for producing 3-hydroxy-γ-butyrolactone> The method for producing 3-hydroxy-γ-butyrolactone of this embodiment includes steps (I), (II), and (III) in this order, and may further include a salt precipitation step.

[0015] <Process (I)> Step (I) is a step of mixing a compound represented by the following general formula (1) (hereinafter also referred to as "compound (1)") with an aqueous solution containing an acidic compound (hereinafter also referred to as "medium") to obtain an intermediate aqueous solution containing a compound represented by the following general formula (2) (hereinafter also referred to as "compound (2)"). Compound (1) is a 4-halogeno-3-hydroxybutyric acid ester, and compound (2) is 3-hydroxy-γ-butyrolactone. In step (I), compound (1) undergoes a cyclization reaction in a medium to produce compound (2) via the intermediate 4-halogeno-3-hydroxybutyric acid.

[0016] [ka]

[0017] In formula (1), X represents a halogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom. A chlorine atom is preferred. In formula (1), R represents an ester protecting group. In this specification, the term "ester protecting group" refers to a group capable of protecting a carboxylic acid as an ester. Examples of the protecting group include an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and a silyl-based protecting group. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a phenyl group, a benzyl group, an α-methylbenzyl group, a phenylpropyl group, a trimethylsilyl group, a tert-butyldimethylsilyl group, and groups in which any of these groups has been partially substituted with a substituent. Examples of the substituent include a halogen atom, a nitro group, a hydroxyl group, an ether group, and an amide group. R is preferably a hydrocarbon group, more preferably an alkyl group. The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or a tert-butyl group, more preferably a methyl group or an ethyl group.

[0018] The compound (1) used in step (I) may be either the (R)-form or the (S)-form, which are optical isomers, and these may be used in combination. The compound (2) produced in step (I) may be either an (R)-isomer or an (S)-isomer, which are optical isomers, or a mixture thereof.

[0019] The medium in step (I) contains an acidic compound and a solvent, and the solvent contains water. In this specification, the term "acidic compound" refers to a compound whose 0.5 M aqueous solution has a pH of 6.0 or less at 20° C. Specific examples include hydrochloric acid, sulfuric acid, nitric acid, formic acid, hydrobromic acid, hydroiodic acid, perchloric acid, phosphoric acid, acetic acid, propionic acid, butyric acid, isobutyric acid, crotonic acid, acrylic acid, methacrylic acid, oxalic acid, succinic acid, phthalic acid, benzoic acid, tartaric acid, lactic acid, glycolic acid, potassium hydrogen oxalate, potassium hydrogen tartrate, potassium hydrogen phthalate, ammonium chloride, and trimethylamine hydrochloride. The medium may contain one or more types of acidic compounds. In terms of facilitating a shortened reaction time, compounds having a pH of 2.0 or less are preferred, and examples of suitable compounds include hydrochloric acid, sulfuric acid, nitric acid, and formic acid. The amount of the acidic compound used in step (I) is preferably 0.05 to 2.0 molar equivalents, more preferably 0.1 to 1.0 molar equivalents, relative to compound (1).

[0020] The solvent in the medium may contain a water-soluble organic solvent as long as the effect of the present invention is not impaired. Examples of water-soluble organic solvents include ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as dioxane and tetrahydrofuran, alcohol solvents such as methanol, ethanol and isopropanol, and nitrile solvents such as acetonitrile. In the medium, the content of water relative to the total mass of the solvent is preferably 30% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 100% by mass. The amount of the solvent used in step (I) is preferably 1 to 10 parts by mass, more preferably 2 to 6 parts by mass, per part by mass of compound (1).

[0021] In step (I), the method for subjecting compound (1) to a cyclization reaction is preferably a method in which compound (1) is added to a medium, mixed to prepare a raw material composition, and the raw material composition is heated. The reaction temperature for the cyclization reaction is preferably 40 to 150° C., more preferably 60 to 120° C., and even more preferably 70 to 110° C. The cyclization reaction may be carried out under reflux by heating up to the boiling point of the medium. It is preferable to adjust the pH of the reaction solution after the initiation of the cyclization reaction and before the completion of the cyclization reaction (pH adjustment step). When the pH adjustment step is performed, the period from the initiation of the cyclization reaction to before the pH adjustment step is called the first reaction step, and the period from after the pH adjustment step to before the completion of the cyclization reaction is called the second reaction step. When an alcohol is produced as a by-product in the cyclization reaction, it is preferable to remove the by-product alcohol before the pH adjustment step (alcohol removal step). When the alcohol removal step is performed, the period from the start of the cyclization reaction to before the alcohol removal step is defined as the first reaction step, and the period from after the pH adjustment step to before the end of the cyclization reaction is defined as the second reaction step. In step (I), after the cyclization reaction is completed, it is preferable to neutralize the reaction solution in which compound (2) is produced (neutralization step) to obtain an intermediate aqueous solution. A preferred embodiment of step (I) comprises a first reaction step, an alcohol removal step, a pH adjustment step, a second reaction step, and a neutralization step in this order.

[0022] (First reaction step) The reaction temperature in the first reaction step, including the preferred range, is the same as the reaction temperature in the cyclization reaction. In the first reaction step, compound (2) is produced, and an acid component (HX) is also produced as a by-product, and when R is a hydrocarbon group, an alcohol (ROH) is also produced as a by-product. After the initiation of the cyclization reaction, the reaction mixture may contain, in addition to compound (2), one or more selected from impurities, unreacted compound (1), and intermediates. The impurity may include γ-crotonolactone (hereinafter also referred to as “compound (3)”) represented by the following formula (3):

[0023] [ka]

[0024] In the first reaction step, it is preferable to carry out the cyclization reaction until the yield (intermediate yield) of compound (2) obtained by the measurement method described below is 10% or more. The yield (intermediate yield) at the end of the first reaction step is preferably 10 to 60%, more preferably 20 to 50%. If the intermediate yield is equal to or greater than the lower limit of the above range, it is easy to shorten the reaction time in the second reaction step, and if it is equal to or less than the upper limit, it is easy to suppress the formation of impurities.

[0025] (Alcohol removal process) When the protecting group R in compound (1) is a hydrocarbon group, it is preferable to remove the alcohol (ROH) produced as a by-product in the cyclization reaction during the cyclization reaction. In the alcohol removal step, at least a portion of the alcohol contained in the reaction solution is removed. It is preferable to remove a larger amount of alcohol, and it is also possible to remove all of the alcohol in the reaction solution. For example, the alcohol in the reaction solution is removed by concentrating the reaction solution under reduced pressure. The amount of the reaction solution removed by concentration under reduced pressure is, for example, preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 1 part by mass of the alcohol in the reaction solution. The reaction time can be shortened by removing the alcohol during the cyclization reaction. In particular, by carrying out the alcohol removal step before the pH adjustment step, the production of the intermediate is promoted and the yield is improved.

[0026] (pH adjustment process) The pH adjustment step is a step of varying the pH of the reaction solution in addition to the change in pH that occurs with an increase in the acid component that is by-produced in the cyclization reaction. The pH is preferably adjusted by adding an alkaline compound to the reaction solution. In this specification, an alkaline compound refers to a compound whose 5% by mass aqueous solution has a pH of 8.0 or higher at 20° C. Specific examples include alkali metal hydroxides (sodium hydroxide, etc.), carbonates (sodium carbonate, potassium carbonate, etc.), and bicarbonates (sodium bicarbonate, etc.).

[0027] In the pH adjustment step, the pH is preferably adjusted to 0.5 to 5.5 at 25°C. The pH is more preferably 1.0 to 4.5, and even more preferably 1.5 to 4.5. When the pH is equal to or higher than the lower limit of the above range, the yield is improved and the impurity formation is inhibited. When the pH is equal to or lower than the upper limit, the impurity formation is inhibited.

[0028] (Second reaction step) In the second reaction step, the reaction solution whose pH has been adjusted in the pH adjustment step is heated to cause a cyclization reaction, which produces an acid component (HX) as a by-product. The reaction temperature in the second reaction step, including the preferred range, is the same as the reaction temperature in the cyclization reaction. The reaction time in the second reaction step is not particularly limited, and is preferably 0.5 to 24 hours, more preferably 1 to 10 hours. When the desired yield is reached, the reaction is terminated by lowering the temperature of the reaction mixture, for example, by allowing the reaction mixture to cool to 25°C. At the end of the second reaction step, the yield of compound (2) obtained by the measurement method described below is, for example, preferably 50 to 100%, more preferably 60 to 100%.

[0029] (neutralization process) Next, the resulting reaction solution is neutralized to obtain a neutralized solution containing water, compound (2) and a neutralized salt. Specifically, an alkaline compound is added to the reaction solution to neutralize it. Examples of alkaline compounds used for neutralization include alkali metal hydroxides (sodium hydroxide, etc.), carbonates (sodium carbonate, potassium carbonate, etc.), and bicarbonates (sodium bicarbonate, etc.). The pH of the neutralized solution after neutralization is preferably 2 to 7 at 25°C.

[0030] In this embodiment, it is preferable that the neutralized salt contains sodium chloride, since this allows for efficient extraction of compound (2). For this reason, it is preferable that X in formula (1) is a chlorine atom and that the acidic compound in the raw material composition contains hydrochloric acid. When a neutralization step is performed, it is preferable that the alkaline compound added contains sodium hydroxide. When a pH adjustment step is performed, it is preferable that the alkaline compound added contains sodium hydroxide.

[0031] <Process (II)> Step (II) is a step of removing water from the intermediate aqueous solution obtained in step (1), which contributes to reducing impurities. The intermediate aqueous solution contains at least compound (2) and water. It may also contain other compounds derived from step (I). For example, it may contain a neutralized salt produced in the neutralization step. The neutralized solution obtained in the neutralization step may be used as the intermediate aqueous solution.

[0032] The intermediate aqueous solution may contain, as impurities, a compound represented by the following formula (4) (hereinafter also referred to as "compound (4)") and oligomers. Compound (4) is 3,4-dihydroxybutyric acid. In this specification, oligomer means a compound having a higher molecular weight than 3-hydroxy-γ-butyrolactone.

[0033] In the intermediate aqueous solution, as shown in the reaction formula below, the ring-opening reaction (reaction to the right) in which compound (2) reacts with water to produce compound (4) and the reverse reaction (reaction to the left) are thought to be in equilibrium. Examples of the oligomer in the intermediate aqueous solution include oligomer (A) formed by dehydration condensation of compound (2) and compound (4), oligomer (B) formed by dehydration condensation of compound (4) itself, and oligomer (C) formed by addition of oligomer (A) to compound (3).

[0034] [ka]

[0035] [ka]

[0036] In step (II), the amount of the by-product compound (4) can be reduced by removing water from the intermediate aqueous solution to shift the equilibrium to the left, and the amount of oligomers can be reduced by reducing the amount of compound (4).

[0037] In step (II), the intermediate aqueous solution is heated to distill off water therein. The heating temperature is preferably 30 to 120° C., more preferably 50 to 100° C. When the heating temperature is equal to or higher than the lower limit of the above range, the efficiency of distilling off water is excellent, and when the heating temperature is equal to or lower than the upper limit, the decomposition of compound (2) and the production of by-products are excellently suppressed.

[0038] The heating in step (II) may be carried out under normal pressure, but is preferably carried out under reduced pressure because the boiling point can be lowered. For example, the pressure of the atmosphere of the intermediate aqueous solution is 500 Torr (approximately 6.67 × 10 4 The lower limit of the pressure is preferably 0.01 Torr or more, more preferably 0.1 Torr or more, in terms of reducing the load on the pressure reducing device.

[0039] In step (II), water is thoroughly removed from the intermediate aqueous solution. Specifically, water is distilled off while heating the intermediate aqueous solution, and water is removed until the distillation stops. The point at which the distillation of water stops is considered to be the end of water removal.

[0040] <Process (III)> Step (III) is a step in which heating is continued even after the removal of water in step (II) is completed, and step (III) contributes to the reduction of impurities. In the equilibrium state immediately after the distillation of water stops in step (II), the open-ring compound (4) remains. Therefore, in step (III), heating is continued to convert compound (4) to compound (2). When heating is carried out under reduced pressure in step (II), it is preferable to continue heating under reduced pressure in step (III).

[0041] The heating temperature T2 in step (II) and the heating temperature T3 in step (III) are preferably approximately equal. For example, T3 is preferably within the range of T2±20°C, more preferably within the range of T2±10°C. The atmospheric pressure P2 in step (II) and the atmospheric pressure P3 in step (III) are preferably approximately equal. For example, P3 is preferably within the range of P2±150 Torr, and more preferably within the range of P2±100 Torr.

[0042] The time for which heating is continued in step (III) (hereinafter also referred to as "continuation time") is 0.5 to 20 hours, preferably 1 to 15 hours, and more preferably 1 to 13 hours. In this specification, the duration means the time from when the removal of water is completed in step (II) to when heating is stopped in step (III). When the duration is equal to or greater than the lower limit of the above range, compound (4) is easily converted to compound (2), and the amount of compound (4) as an impurity can be sufficiently reduced.When the duration is equal to or less than the upper limit of the above range, side reactions such as polymerization can be easily suppressed, and oligomers can be reduced.

[0043] The duration of step (III) can also be determined based on the oligomer content. Specifically, it is preferable to continue heating until the oligomer content becomes 20% or less of the total mass of the reaction product (hereinafter also referred to as "crude product") obtained at the end of step (III). In this specification, the oligomer content (unit: %) is a value expressed as a percentage of the ratio of the "total peak area of ​​oligomers" to the sum of the "peak area of ​​compound (2)" and the "total peak area of ​​oligomers," where the peak having a shorter retention time than the peak of compound (2) in a chromatogram obtained by gel permeation chromatography is the oligomer peak. The content of oligomers can be adjusted by the duration of step (III). If the duration is too short or too long, the content of oligomers tends to be high.

[0044] <Salt precipitation process> When the crude product obtained after the completion of the holding step (III) contains salts formed in the neutralization step, it is preferable to carry out a salt precipitation step to remove the salts from the viewpoint of ease of handling. In the salt precipitation step, a solvent is added to the crude product to precipitate salts and extract the target product. The precipitated salts are preferably removed by filtration (filtration step).

[0045] The solvent to be added to the crude composition is preferably at least one selected from the group consisting of alcohols having 2 to 6 carbon atoms, ketones having 4 to 8 carbon atoms, nitriles having 2 to 6 carbon atoms, and ethers having 4 to 8 carbon atoms. The alcohol having 2 to 6 carbon atoms is preferably ethanol, propanol, isopropanol, butanol, or 2-butanol. As the ketone having 4 to 8 carbon atoms, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclohexanone, and methyl isobutyl ketone are preferred. As the nitrile having 2 to 6 carbon atoms, acetonitrile, propionitrile, and butyronitrile are preferred. As the ether having 4 to 8 carbon atoms, diethyl ether, tetrahydrofuran, methyl tert-butyl ether, diisopropyl ether, and dioxane are preferred.

[0046] The amount of solvent added is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, per part by mass of compound (1) used in step (I). When the amount is equal to or greater than the lower limit of the above range, the salt is sufficiently precipitated, resulting in an excellent effect of improving the purity of the crude product. When the amount is equal to or less than the upper limit, the load during vacuum concentration of the filtrate obtained in the subsequent filtration step can be reduced.

[0047] After adding the solvent to the crude composition, it is preferable to cool the mixture to promote precipitation of the salt. The cooling temperature is, for example, preferably -40 to 15°C, more preferably -30 to 10°C. The salt precipitated in the salt precipitation step preferably contains sodium chloride. The sodium chloride content of the precipitate in the salt precipitation step is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. It may even be 100% by mass.

[0048] After the salt precipitation step, it is preferable to filter off the precipitate using a known method (filtration step). The filtrate obtained in the filtration step contains the target compound, compound (2), which can be concentrated under reduced pressure to obtain crude compound (2). Furthermore, the procedure of adding the above-mentioned solvent to the obtained crude product to precipitate a salt, filtering off the precipitate, and concentrating the filtrate under reduced pressure may be repeated one or more times.

[0049] According to this embodiment, as shown in the examples described later, after the cyclization reaction of compound (1), steps (II) and (III) are added, and heating is continued for a specific duration in step (III), thereby reducing the amount of oligomers contained in the crude product and the crude product, and increasing the purity. Conventionally, purification steps such as distillation or column chromatography have been required to remove such oligomers, but if the oligomer content is 20% or less based on the total mass of the crude product, such purification steps can be omitted, contributing to improved productivity and reduced costs in the production of 3-hydroxy-γ-butyrolactone. According to this embodiment, as shown in the examples described later, the content of oligomers relative to the total mass of the crude product can be reduced to 20% or less without carrying out purification steps such as distillation or column chromatography.

[0050] <Method for producing (meth)acrylic acid ester> The method for producing a (meth)acrylic acid ester of the present embodiment is a method for producing 3-hydroxy-γ-butyrolactone by the production method of the above embodiment, and then reacting the resulting 3-hydroxy-γ-butyrolactone with (meth)acrylic anhydride to produce a (meth)acrylic acid ester (5) represented by the following formula (5): The (meth)acrylic acid ester (5) represented by the formula (5) may be either an (R)-isomer or an (S)-isomer, which are optical isomers, or a mixture thereof.

[0051] [ka]

[0052] In formula (5), Y represents a hydrogen atom or a methyl group. The reaction between 3-hydroxy-γ-butyrolactone and (meth)acrylic anhydride (hereinafter also referred to as "esterification reaction") is preferably carried out in the presence of a base. Furthermore, by adding pyridine, 4-dimethylaminopyridine, or the like to the system, the reaction can be completed in a shorter reaction time. The base is not particularly limited as long as it neutralizes the generated acid, and examples thereof include triethylamine, pyridine, 2-methylpyridine, 2-methyl-5-ethylpyridine, 2,6-dimethylpyridine, triethylenetetramine, triethanolamine, piperazine, sodium hydrogencarbonate, etc. These may be used alone or in combination of two or more. The amount of (meth)acrylic anhydride used is preferably 0.9 to 1.5 moles per mole of 3-hydroxy-γ-butyrolactone. The amount of the base used is preferably 0.5 to 1.6 moles per mole of 3-hydroxy-γ-butyrolactone.

[0053] In the esterification reaction, a solvent is not essential, but may be used for temperature control. Examples of the solvent include ketone solvents such as 2-butanone and 4-methyl-2-pentanone, halogenated hydrocarbon solvents such as methylene chloride and chloroform, ether solvents such as diethyl ether, tetrahydrofuran and methyl tert-butyl ether, and aromatic hydrocarbon solvents such as benzene, toluene and xylene.

[0054] The reaction temperature in the esterification reaction is preferably −80° C. to 100° C., more preferably −50° C. to 60° C., and even more preferably −20° C. to 20° C. If the temperature is equal to or higher than the lower limit of the above range, the reaction rate tends to be sufficiently fast, and if the temperature is equal to or lower than the upper limit, side reactions tend to be sufficiently slow.

[0055] In the esterification reaction, it is preferable to use a polymerization inhibitor and perform air bubbling in order to prevent polymerization due to high temperatures. Examples of the polymerization inhibitor include phenolic compounds such as hydroquinone and p-methoxyphenol, amine compounds such as N,N'-diisopropyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, and N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-[H-(OCH2CH2) n —O]-2,2,6,6-tetramethylpiperidine-N-oxyl (where n = 1 to 18) and other N-oxyl compounds. The polymerization inhibitors may be used alone or in combination of two or more, and the amount used is not particularly limited and may be determined appropriately.

[0056] In this manner, the (meth)acrylic acid ester (5) is obtained.

[0057] <Polymer manufacturing method> The method for producing a polymer according to the present embodiment is a method for producing a (meth)acrylic acid ester (5) by the method for producing a (meth)acrylic acid ester according to the present embodiment, and polymerizing a monomer containing the obtained (meth)acrylic acid ester (5) to produce a polymer.

[0058] The monomer used to produce the polymer may be the (meth)acrylic acid ester (5) alone, or a monomer mixture containing one or more other monomers copolymerizable with the (meth)acrylic acid ester (5). The other monomers have polymerizable multiple bonds that are cleaved during the polymerization reaction to form polymer chains, and the polymerizable multiple bonds are preferably ethylenic double bonds. As the other monomers, known monomers can be used appropriately depending on the intended use of the polymer.

[0059] The polymerization of the monomers can be carried out using a polymerization initiator, and known radical polymerization initiators can be used as the polymerization initiator. As the polymerization method, a known polymerization method such as a solution polymerization method or a dropping polymerization method can be used. In the polymerization step, for example, a polymerization initiator is added to a monomer solution in which a monomer is dissolved in a solvent, and the polymerization temperature is adjusted to a temperature appropriate for the type of polymerization initiator to initiate the polymerization reaction, thereby obtaining a polymerization reaction liquid containing a polymer. After the polymerization step, a purification step can be carried out by a known method to remove impurities and obtain the target polymer.

[0060] The (meth)acrylic acid ester (5) is useful as a monomer for producing a polymer for lithography. The method for producing a polymer according to the present embodiment is suitable for producing a polymer for lithography. When the target polymer is a polymer for lithography, examples of the other monomer include a monomer having an acid-leaving group, a monomer having a lactone ring (excluding (meth)acrylic acid ester (5)), a monomer having a hydrophilic group (having neither an acid-leaving group nor a lactone ring), etc. The other monomers preferably include at least one monomer having an acid-leaving group. The monomer having an acid-dissociable group is preferably a (meth)acrylic acid ester having an acid-dissociable group.

[0061] The "hydrophilic group" is at least one of a monovalent group represented by -C(CF3)2-OH, a hydroxy group, a cyano group, a methoxy group, a carboxy group, and an amino group. The "acid-dissociable group" is a group having a bond that is cleaved by an acid (for example, an acid generated from a compound that generates an acid upon irradiation with actinic rays or radiation), and a part or all of the acid-dissociable group is dissociated from the main chain of the polymer upon cleavage of the bond. Lithographic polymers having structural units based on monomers having an acid-leaving group exhibit the effect of enabling resist pattern formation when used as chemically amplified resist compositions in combination with compounds that generate acid upon exposure to actinic rays or radiation. Specifically, when the resist composition is applied to a substrate or the like to form a resist film, and the resist film is selectively exposed to light, acid is generated in the exposed areas, and the acid-leaving groups are eliminated by the action of the acid, resulting in a difference in solubility in alkali (developer) between the exposed and unexposed areas. A resist pattern is formed by developing the resist film.

[0062] In the production of a polymer for lithography, the content of the (meth)acrylic acid ester (5) is preferably 1 to 60 mol %, more preferably 10 to 50 mol %, and even more preferably 15 to 40 mol %, based on the total amount of monomers (100 mol %). When the content is equal to or greater than the lower limit of the range, the performance of the (meth)acrylic acid ester (5) is fully exhibited, while when the content is equal to or less than the upper limit, the performance of the other monomers is fully exhibited, resulting in better lithography properties.

[0063] The weight average molecular weight (Mw) of the polymer for lithography is preferably 1,000 to 100,000, more preferably 2,000 to 50,000, and particularly preferably 3,000 to 30,000. When the weight average molecular weight is at least the lower limit of the above range, the polymer solution for lithography has better film-forming properties when coated on a substrate and dried. When the weight average molecular weight is at most the upper limit of the above range, the polymer solution for lithography can be easily coated with a uniform film thickness, and the resist properties are good. The weight average molecular weight of the polymer for lithography is a value calculated as standard polystyrene as measured by gel permeation chromatography (GPC).

[0064] <Method for producing resist composition> A polymer for lithography can be produced by the polymer production method of this embodiment, and the obtained polymer for lithography can be used to produce a resist composition. The resist composition includes a lithographic polymer and a resist solvent. The resist composition may contain various additives, such as surfactants, other quenchers, sensitizers, antihalation agents, storage stabilizers, and antifoaming agents, as necessary. Any additives known in the art can be used. The amounts of these additives are not particularly limited and may be determined appropriately.

[0065] The chemically amplified resist composition further contains a compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as a "photoacid generator"). The photoacid generator can be appropriately selected from compounds known in chemically amplified resist compositions and used. One photoacid generator may be used alone, or two or more photoacid generators may be used in combination.

[0066] The resist composition can be produced by dissolving a lithography polymer and, if necessary, components such as a photoacid generator and additives in a resist solvent.

[0067] <Method for manufacturing a substrate having a pattern formed thereon> The method for manufacturing a substrate of the present embodiment is a method for manufacturing a substrate having a pattern formed thereon through the steps of applying the resist composition obtained above onto a substrate to form a resist film, exposing the resist film to light, and developing the exposed resist film using a developer. An example of the method for manufacturing the substrate of this embodiment will be described below.

[0068] First, a resist composition is applied by spin coating or the like to the surface of a substrate to be processed, such as a silicon wafer, on which a desired fine pattern is to be formed. Then, the substrate to be processed on which the resist composition has been applied is dried by a baking treatment (pre-bake) or the like, thereby forming a resist film on the substrate. The resist film is then exposed to light having a wavelength of 250 nm or less to form a latent image (exposure). The light to be irradiated is preferably a KrF excimer laser, an ArF excimer laser, an F2 excimer laser, or an EUV excimer laser, with an ArF excimer laser being particularly preferred. Electron beam irradiation may also be used. Alternatively, immersion exposure may be performed by irradiating light in a state where a high refractive index liquid such as pure water, perfluoro-2-butyltetrahydrofuran, or perfluorotrialkylamine is interposed between the resist film and the final lens of the exposure tool.

[0069] After exposure, the resist film is subjected to an appropriate heat treatment (post-exposure bake, PEB), and then an alkaline developer is brought into contact with the resist film to dissolve and remove the exposed portions in the developer (development). Examples of the alkaline developer include known ones. After development, the substrate is appropriately rinsed with pure water, etc. In this way, a resist pattern is formed on the substrate to be processed.

[0070] The substrate on which the resist pattern has been formed is appropriately heat treated (post-baked) to strengthen the resist, and the portions without resist are selectively etched. After etching, the resist is removed with a stripper to obtain a substrate on which a fine pattern has been formed. [Example]

[0071] The present invention will be explained in more detail below using examples, but the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the invention.

[0072] <Measurement method> In the following example, the target compound is (S)-3-hydroxy-γ-butyrolactone, the raw material compound is ethyl (S)-4-chloro-3-hydroxybutyrate, the intermediate is (S)-4-chloro-3-hydroxybutyric acid, and the impurities are γ-crotonolactone, 3,4-dihydroxybutyric acid, and oligomers.

[0073] (Method for measuring yield) The product was analyzed using a gas chromatograph, and the yield was calculated from the area of ​​the peak corresponding to each substance in the resulting chromatogram using the following formula (1). Yield (%) = {target compound / (raw compound + intermediate + target compound + impurities)} × 100 (1)

[0074] (Method for measuring oligomer content) A gel permeation chromatograph (model name "HLC-8320GPC", manufactured by Tosoh Corporation) was used, and two "KF-801" columns were connected in series. A RI detector was used to obtain a chromatogram by gel permeation chromatography. The peak detected before the target compound was determined to be an oligomer, and the content of the oligomer was calculated from the area of ​​the peak corresponding to each substance in the obtained chromatogram using the following formula (2). Oligomer content (%) = {(oligomer) / (target compound + oligomer)} × 100 (2)

[0075] <Examples and Comparative Examples> The following Examples 1 to 8 are working examples, and Example 9 is a comparative example.

[0076] [Example 1] A glass flask equipped with a thermometer, a condenser, and a stirrer was charged with 11.4 parts by mass of 35% hydrochloric acid, 90 parts by mass of water, and 22 parts by mass of ethyl (S)-4-chloro-3-hydroxybutyrate, and the mixture was heated under reflux for 30 minutes (first reaction step). The yield (intermediate yield) after the first reaction step was 20%. The amount of hydrochloric acid relative to the amount of ethyl (S)-4-chloro-3-hydroxybutyrate was 0.8 molar equivalents. Thereafter, the pressure was reduced and 28 parts by mass of the reaction liquid was distilled off (alcohol removal step). A 40% by mass aqueous solution of sodium hydroxide was added to the remaining reaction liquid to adjust the pH at 35° C. to 1.5 (pH adjustment step). Thereafter, the mixture was heated under reflux for 3 hours and allowed to cool to 25° C. (second reaction step). The yield after the second reaction step was 84%. Thereafter, a 40% by mass aqueous solution of sodium hydroxide was added to the reaction liquid to adjust the pH at 25° C. to 2.0 (neutralization step). Thereafter, the reaction solution was heated to 70°C while reducing the pressure to 50 Torr or less, and water was distilled off (step (II)). After completion of the distillation of water, the operation of heating to maintain 70°C while reducing the pressure to 50 Torr or less was continued for 1.25 hours (step (III)). The content of oligomers relative to the total mass of the crude product obtained at the end of step (III) was 13.2%.

[0077] [Examples 2-8] The same operation as in Example 1 was carried out, except that the duration of step (III) was changed as shown in Table 1. Table 1 shows the content of oligomers relative to the total mass of the obtained crude product.

[0078] [Example 9] The same procedure as in Example 1 was carried out, except that step (III) was not carried out. The oligomer content relative to the total mass of the crude product obtained at the end of step (II) is shown in Table 1.

[0079] [Table 1]

[0080] As shown in the results in Table 1, the content of oligomer impurities was lower in Examples 1 to 8, which included Step (III), compared to Example 9, which did not include Step (III). In particular, in Examples 1 to 6, in which the duration of Step (III) was within the range of 1 to 13 hours, the content of oligomers was reduced to 20% or less.

[0081] [Manufacturing Example 1] A glass flask equipped with a thermometer, a condenser, and a stirrer was charged with 10.4 parts by mass of 35% hydrochloric acid, 88 parts by mass of water, and 20.1 parts by mass of ethyl (S)-4-chloro-3-hydroxybutyrate, and the mixture was heated under reflux for 30 minutes (first reaction step). The yield (intermediate yield) after the first reaction step was 28%. The amount of hydrochloric acid relative to the amount of ethyl (S)-4-chloro-3-hydroxybutyrate was 0.8 molar equivalents. Thereafter, the pressure was reduced and 32 parts by mass of the reaction liquid was distilled off (alcohol removal step). A 40% by mass aqueous solution of sodium hydroxide was added to the remaining reaction liquid to adjust the pH at 25° C. to 1.5 (pH adjustment step). Thereafter, the mixture was heated under reflux for 3 hours and allowed to cool to 25° C. (second reaction step). The yield after the second reaction step was 78%. Thereafter, a 40% by mass aqueous solution of sodium hydroxide was added to the reaction liquid to adjust the pH at 25° C. to 2.2 (neutralization step). Thereafter, the reaction solution was heated to 70°C while reducing the pressure to 50 Torr or less, and water was distilled off (step (II)). After completion of the distillation of water, the reaction solution was heated to maintain 70°C while reducing the pressure to 50 Torr or less for 2.5 hours (step (III)). The content of oligomers relative to the total mass of the crude product obtained at the end of step (III) was 12.2%. Then, 50.5 parts by mass of 2-propanol was added to the obtained crude product, and the mixture was cooled to -15°C to precipitate a salt (salt precipitation step). The precipitate was filtered off, and the obtained filtrate was concentrated under reduced pressure to obtain crude (S)-3-hydroxy-γ-butyrolactone. The content of oligomers relative to the total mass of the crude product was 13.5%.

Claims

1. Step (I): A step of mixing a compound (1) represented by the following general formula (1) with an aqueous solution containing an acidic compound, and subjecting the compound (1) to a cyclization reaction to obtain an intermediate aqueous solution containing 3-hydroxy-γ-butyrolactone represented by the following general formula (2): Step (II): Heating the intermediate aqueous solution to remove water from the intermediate aqueous solution; and Step (III): continuing the heating after the removal of water in step (II) is completed; The method for producing 3-hydroxy-γ-butyrolactone has the following steps. 【Chemical 1】 (In formula (1), X represents a halogen atom, and R represents an ester protecting group.)

2. The method according to claim 1, wherein in the step (III), the heating is continued for 0.5 to 20 hours.

3. The method according to claim 1 or 2, wherein in the step (III), the heating is continued until the content of oligomers becomes 20% or less.

4. The method according to any one of claims 1 to 3, wherein X is a chlorine atom.

5. The method according to any one of claims 1 to 4, wherein R is a methyl group or an ethyl group.

6. The method according to any one of claims 1 to 5, wherein the acidic compound is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and formic acid.

7. The method according to any one of claims 1 to 6, wherein the reaction temperature in step (I) is 40 to 150°C.

8. The method according to any one of claims 1 to 7, wherein the heating temperature in the steps (II) and (III) is 30 to 120°C.

9. The method according to any one of claims 1 to 8, wherein the heating in the steps (II) and (III) is carried out under a reduced pressure of 500 Torr or less.

10. A method for producing a (meth)acrylic acid ester, comprising producing 3-hydroxy-γ-butyrolactone by the production method according to any one of claims 1 to 9, and reacting the resulting 3-hydroxy-γ-butyrolactone with (meth)acrylic anhydride to produce a (meth)acrylic acid ester (5) represented by the following formula (5): 【Chemistry 2】 (In formula (5), Y represents a hydrogen atom or a methyl group.)

11. A method for producing a polymer, comprising producing the (meth)acrylic acid ester (5) by the production method according to claim 10, and polymerizing a monomer containing the obtained (meth)acrylic acid ester (5).

12. The method for producing a polymer according to claim 11, wherein the polymer is a polymer for lithography.

13. A method for producing a resist composition, comprising producing a polymer for lithography by the production method according to claim 12, and using the resulting polymer for lithography to produce a resist composition.

14. 14. A method for producing a substrate having a pattern formed thereon, comprising: a step of producing a resist composition by the production method according to claim 13; a step of applying the resist composition obtained onto a substrate to form a resist film; a step of exposing the resist film to light; and a step of developing the exposed resist film using a developer.

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