Method for manufacturing a resist composition

Abstract

The present invention provides a method for manufacturing a resist composition in which impurities are further reduced and the occurrence of defects in the resist film can be suppressed. [Solution] A method for manufacturing a resist composition, comprising: manufacturing a resist composition using a manufacturing apparatus equipped with a filter including a filter; removing the filter from the manufacturing apparatus; cleaning the manufacturing apparatus from which the filter has been removed using a cleaning solution; analyzing the cleaning solution used in the cleaning step; and attaching another filter to the manufacturing apparatus from which the filter has been removed, and manufacturing a resist composition, wherein, before the manufacturing step, the cleaning step and the analysis step are each performed at least once until the concentration of the resist composition components contained in the cleaning solution in the analysis step is less than 300 ppb.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a resist composition. [Background Art]

[0002] In lithography technology, a method is used in which, for example, a resist film made of a resist material is formed on a substrate, the resist film is subjected to selective exposure and then development treatment, thereby forming a resist pattern of a predetermined shape on the resist film.

[0003] In the manufacture of semiconductor devices and liquid crystal display elements, progress in lithography technology has rapidly promoted the miniaturization of patterns and the multilayering of substrates. Along with the progress of miniaturization of resist patterns, resist materials are required not only to improve various lithography properties but also to suppress the occurrence of defects in resist films. Accordingly, there is an increasing demand for removing foreign substances (impurities) mixed into resist compositions. In particular, impurities contained in a resist composition may cause the occurrence of defects. Therefore, control of the concentration of impurities contained in a resist composition is considered important.

[0004] For example, Patent Document 1 discloses a purified resist composition in which metal impurities contained in the resist composition are reduced and problems such as pattern collapse are less likely to occur, and in order to obtain the purified resist composition produced by the production method, a method for producing a purified resist product is described, which comprises the step (i) of filtering a resist composition with a filter having a porous structure in which adjacent spherical cells communicate with each other. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent No. 7195418 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In recent years, with the further miniaturization of patterns and the multilayering of substrates, the demand for reducing impurities in resist compositions has become even stricter in semiconductor manufacturing processes. Therefore, there is a greater need than ever for technologies that can suppress defect occurrence in resist films. The present invention has been made in view of the above circumstances, and aims to provide a method for producing a resist composition in which impurities are further reduced and the occurrence of defects in the resist film can be suppressed. [Means for solving the problem]

[0007] Through their investigations, the inventors have found that conventional cleaning methods result in insufficient cleaning of the resist composition manufacturing equipment. As a result, organic components originating from previous resist composition manufacturing lots remain in the equipment and contaminate the next resist composition, making it difficult to manufacture a resist composition that can suppress defect occurrence. Furthermore, the possibility of residual components from previous manufacturing lots contaminating the next resist composition can lead to problems such as a significant decrease in the efficiency of factor analysis when a problem occurs. This invention was made in view of the above circumstances, and it was found that a method for producing a resist composition can be obtained in which impurities in the resist composition are further reduced and defect occurrence in the resist film is suppressed, thus completing the present invention.

[0008] In other words, one aspect of the present invention involves the steps of: manufacturing a resist composition using a manufacturing apparatus equipped with a filter including a filter, and then removing the filter from the manufacturing apparatus; A cleaning step in which the manufacturing apparatus from which the filtration filter has been removed is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, A manufacturing process for manufacturing a resist composition involves attaching another filter to the manufacturing apparatus from which the aforementioned filter has been removed, A method for producing a resist composition having the following characteristics: The present invention relates to a method for producing a resist composition, wherein, prior to the manufacturing process, the washing process and the analysis process are each performed at least once until the concentration of the resist composition components contained in the washing solution in the analysis process is less than 300 ppb. [Effects of the Invention]

[0009] According to the method for producing a resist composition of the present invention, impurities in the resist composition can be reduced, and defect occurrence in the resist film can be suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing one embodiment of a manufacturing apparatus used in the present invention. [Modes for carrying out the invention]

[0011] In this specification and in the claims, "mass%" and "weight%" are synonymous, "parts by mass" and "parts by weight" are synonymous, and "mass ratio" and "weight ratio" are synonymous.

[0012] [Method for manufacturing a resist composition] A method for manufacturing a resist composition according to an embodiment of the present invention includes the steps of: manufacturing a resist composition using a manufacturing apparatus equipped with a filter including a filter, and then removing the filter from the manufacturing apparatus; A cleaning step in which the manufacturing apparatus from which the filtration filter has been removed is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, A manufacturing process for manufacturing a resist composition involves attaching another filter to the manufacturing apparatus from which the aforementioned filter has been removed, A method for producing a resist composition having the following characteristics: Prior to the manufacturing process, the washing process and the analysis process are each performed at least once until the concentration of the resist composition components contained in the washing solution in the analysis process is less than 300 ppb.

[0013] The cleaning process allows for the cleaning of the manufacturing equipment after the filtration filter has been removed. This removes residue from the resist composition manufactured before the cleaning process (hereinafter sometimes referred to as the first resist composition), preventing it from contaminating the resist composition manufactured afterward (hereinafter sometimes referred to as the second resist composition), thus obtaining a high-purity resist composition. By cleaning the manufacturing equipment after removing the filtration filter, the used filter, which can be a source of impurities, is removed, enabling highly efficient and rapid cleaning of the manufacturing equipment, thus facilitating advanced cleaning. A high-purity resist composition can be obtained by removing the filtration filter and using an unused one as another filtration filter. It is preferable to use a filtration filter that has been pre-cleaned with an organic solvent, even if it is unused. Furthermore, a high-purity resist composition can be obtained by performing both the washing and analysis steps at least once until the concentration of components of the resist composition contained in the washing solution is less than 300 ppb. Since it can be confirmed that organic components, which were previously difficult to remove from the manufacturing equipment, have been sufficiently removed, the contamination of the first resist composition residue produced before the washing step can be efficiently prevented.

[0014] <Process of removing the filtration filter from the manufacturing equipment> A method for manufacturing a resist composition according to an embodiment of the present invention includes the step of manufacturing a resist composition using a manufacturing apparatus equipped with a filter that includes a filter, and then removing the filter from the manufacturing apparatus.

[0015] The filtration filter is configured to be removable from the filter 140. According to this configuration, the filtration filter can be removed, and the manufacturing apparatus 100 other than the filtration filter can be cleaned with a cleaning liquid in the cleaning step described later.

[0016] (Resist Composition) The resist composition according to the embodiment of the present invention is not particularly limited as long as it can form a resist film, and examples thereof include a resist composition containing a polymer and an organic solvent. Further, as one embodiment of the resist composition, there can be mentioned a resist composition containing, as polymers, a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes by the action of a known acid, an acid generator component (B) (hereinafter also referred to as "component (B)") that generates an acid upon exposure, and an organic solvent component (S) (hereinafter also referred to as "component (S)"). The resist composition may further contain, as an optional component, at least one compound (E) (hereinafter also referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxo acids and derivatives thereof. The resist composition may further contain, as optional components, an acid diffusion control component (D) (hereinafter referred to as "component (D)") and a fluorine-based additive component as a hydrophobic resin (hereinafter referred to as "component (F)").

[0017] The component (A) is not particularly limited, and those conventionally proposed as base components for resist compositions can be used.

[0018] Examples of the component (A) include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, acrylic resins, polyvinyl acetate resins, cellulose resins, styrene resins, hydroxystyrene resins, or copolymer resins thereof. As the component (A), for example, base components described in Japanese Patent Laid-Open No. 2025-178097, International Publication No. WO 2024 / 053689, Japanese Patent Laid-Open No. 2023-010711, and Japanese Patent Laid-Open No. 2004-43777 can be used. (A) More specifically, it is preferable that the component (A) has a constituent unit (a1) containing an acid-degradable group whose polarity increases with the action of an acid, a constituent unit (a10) containing a hydroxystyrene skeleton, and further, it may have a constituent unit (a2) containing any of a lactone-containing cyclic group, an -SO2--containing cyclic group, or a carbonate-containing cyclic group, a constituent unit (a3) ​​containing a polar group-containing aliphatic hydrocarbon group, or a constituent unit (a4) containing an acid-nondissociable aliphatic cyclic group.

[0019] (B) The component is not particularly limited, and any acid generators previously proposed for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts; oximesulfonate-based acid generators; diazomethane-based acid generators such as bisalkyl or bisarylsulfonyl diazomethanes and poly(bissulfonyl) diazomethanes; nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators, among many others. (B) For example, the acid generators described in Japanese Patent Publication No. 2025-063109, Japanese Patent Publication No. 2023-010711, and International Publication No. 2023 / 162552 can be used as component (B).

[0020] Furthermore, the (S) component can be any solvent that can dissolve each component used to form a homogeneous solution, and any solvent can be appropriately selected from those conventionally known as solvents for chemically amplified resist compositions.

[0021] Component (S) can be any substance capable of dissolving the polymer, such as lactones, ketones, polyhydric alcohols; compounds having ester bonds such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate; derivatives of polyhydric alcohols such as monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or compounds having ether bonds such as monophenyl ether [among these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME)]; cyclic ethers such as dioxane; esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents, dimethyl sulfoxide, etc.

[0022] Component (D) acts as an acid diffusion control agent component that traps the acid generated by exposure in the resist composition. Component (D) is not particularly limited, and any acid diffusion control agent previously proposed for chemically amplified resist compositions can be used. (D) For example, an acid diffusion control agent described in Japanese Patent Publication No. 2025-178097 can be used as component (D).

[0023] Component (F) is used to impart water repellency to the resist film and, by being used as a separate resin from component (A), improves lithography properties. As component (F), for example, fluorine-containing polymer compounds described in Japanese Patent Publication No. 2010-002870, Japanese Patent Publication No. 2010-032994, Japanese Patent Publication No. 2010-277043, Japanese Patent Publication No. 2011-13569, and Japanese Patent Publication No. 2011-128226 can be used.

[0024] When a resist film is formed using the resist composition and selective exposure is performed on the resist film, acid is generated in the exposed areas of the resist film. The solubility of component (A) in the developer changes due to the action of this acid, while the solubility of component (A) in the developer does not change in the unexposed areas of the resist film. As a result, a difference in solubility in the developer occurs between the exposed and unexposed areas of the resist film. Therefore, when the resist film is developed, if the resist composition is positive type, the exposed areas of the resist film are dissolved and removed to form a positive type resist pattern, and if the resist composition is negative type, the unexposed areas of the resist film are dissolved and removed to form a negative type resist pattern.

[0025] In this disclosure, a resist composition in which the exposed portion of the resist film is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which the unexposed portion of the resist film is dissolved and removed to form a negative resist pattern is referred to as a negative resist composition. Furthermore, the resist composition according to the embodiment of the present invention may be used for an alkaline development process in which an alkaline developer is used for the development process during resist pattern formation, or for a solvent development process in which a developer containing an organic solvent (organic developer) is used for the development process. In other words, the resist composition according to the embodiment of the present invention may be a "positive-type resist composition for alkaline development processes" that forms a positive-type resist pattern in an alkaline development process, or a "negative-type resist composition for solvent development processes" that forms a negative-type resist pattern in a solvent development process.

[0026] The above-mentioned positive-type resist composition and negative-type resist composition are not particularly limited, and known compositions can be used, such as KrF resist, ArF resist, EUV resist, EB resist, etc. For example, resist compositions described in Japanese Patent Publication No. 2021-21773, Japanese Patent Publication No. 2019-159323, Japanese Patent Publication No. 2021-92759, Japanese Patent Publication No. 2021-92659, Japanese Patent Publication No. 2017-37108, Japanese Patent Publication No. 2017-37300, Japanese Patent Publication No. 2020-90628, etc. can be used.

[0027] (Preparation of the first resist composition) In this process, the first resist composition is manufactured using a manufacturing apparatus. There are no particular restrictions on the method for manufacturing the first resist composition, but the components constituting the first resist composition are introduced into the manufacturing apparatus, and other components are mixed in as needed. The mixing of the components constituting the first resist composition can be carried out under known conditions. It is preferable to use an unused filter for the filtration filter of the manufacturing apparatus used to manufacture the first resist composition. Details of the manufacturing apparatus will be described later.

[0028] (manufacturing equipment) The manufacturing apparatus used in the embodiments of the present invention is not particularly limited as long as it includes a filter including a filtration filter and is capable of producing a resist composition. The manufacturing apparatus may further include, for example, a tank, piping, a pump, a supply port and valves. Figure 1 is a schematic diagram showing one embodiment of a manufacturing apparatus used in an embodiment of the present invention. The manufacturing apparatus 100 includes a filter 140 containing a filtration filter and a tank 101, the tank 101 having a supply port 161 for supplying resist composition material. The tank 101 and the filter 140 containing the filtration filter are connected by a supply pipe 110, allowing fluid (resist composition, cleaning liquid, etc.) to be transferred between the tank 101 and the filter 140. A valve 132 and a pump 151 are located in the supply pipe 110.

[0029] In Figure 1, the manufacturing apparatus 100 includes a tank 101 and a filter 140 including a filtration filter, but the manufacturing apparatus that can be used in the method for manufacturing a resist composition according to the embodiment of the present invention is not limited to this.

[0030] In the manufacturing apparatus 100, the resist composition material supplied to the manufacturing apparatus 100 from the supply port 161 flows into the filter 140 via the tank 101, valve 132, and pump 151. The fluid discharged from the filter 140 is collected in the tank 101 via valve 131. The manufacturing apparatus 100 may also include a valve 133 for discharging the manufactured resist composition to the outside. The resist composition produced by the manufacturing apparatus 100 can be stored in the container 102 as the final product. The resist composition filtered by the filter 140 can be stored in the container 102 by switching valves 131 and 133 provided in the circulation piping 109.

[0031] <Washing process> The cleaning step in the embodiment of the present invention is a step of cleaning the manufacturing apparatus from which the filtration filter has been removed using a cleaning solution. In the cleaning process, at least a part of the manufacturing apparatus (hereinafter sometimes simply referred to as the manufacturing apparatus) from which the filtration filter has been removed may be cleaned, and it is preferable that all parts in contact with the liquid inside the manufacturing apparatus are cleaned. The cleaning process may include a pre-cleaning process, which will be described later.

[0032] There are no particular restrictions on the cleaning method for the manufacturing equipment, and known methods can be used. An example of cleaning the manufacturing equipment will be explained using Figure 1. The arrows in Figure 1 indicate the direction of liquid flow. In the case of the manufacturing equipment illustrated in Figure 1, one method is to supply the cleaning liquid into the manufacturing equipment from a supply port 161 provided in the tank 101, close valve 133, then open valves 132 and 131 so that the cleaning liquid flows in the direction of liquid flow, and transfer the cleaning liquid through the supply pipe 110 and circulation pipe 109 to clean the manufacturing equipment. An example of the cleaning method will be explained in more detail using the manufacturing equipment 100 in Figure 1.

[0033] First, the cleaning solution is supplied into the manufacturing apparatus from the supply port 161. There are no particular restrictions on the amount of cleaning solution supplied, but it is preferable to supply an amount sufficient to thoroughly clean the wetted parts of the manufacturing apparatus. The amount of cleaning solution used for a single cleaning cycle is preferably 5% or more by volume of the tank 101's capacity, more preferably 10% or more by volume, and even more preferably 15% or more by volume, in addition to the amount needed to fill the inside of the piping, pump, filter, and valve. The cleaning solution according to the embodiment of the present invention will be described later.

[0034] There are no particular limitations on the method of cleaning the manufacturing apparatus 100 using the cleaning solution. The cleaning fluid supplied from the supply port 161 to the tank 101 is circulated back to the tank 101 via the supply piping 110, pump 151, filterless filter 140, and circulation piping 109 (circulation cleaning). At this time, valves 132 and 131 are opened, valve 133 is closed, and then pump 151 is operated. One cleaning cycle is defined as the point at which the entire amount of cleaning solution supplied to tank 101 is returned to tank 101. The "total amount" refers to at least 90% by volume of the supplied cleaning solution, with 95% by volume or more being more preferable.

[0035] By cleaning while transferring the cleaning solution, the components of the resist composition adhering to the wetted parts of the tank 101, supply piping 110, pump 151, filter 140, valve 131, and circulation piping 109 can be efficiently dispersed and / or more efficiently dissolved by the cleaning solution, thereby cleaning the manufacturing equipment.

[0036] The cleaning solution supplied into the manufacturing apparatus may be used to clean the inside of the tank 101 before being transferred within the manufacturing apparatus (for example, through the supply pipe 110 and the circulation pipe 109). There are no particular limitations on the method of cleaning the inside of the tank 101 using the cleaning solution, but one example is to clean it by rotating an agitator (not shown) provided in the tank 101. There are no particular limitations on the time for cleaning the tank with the cleaning solution, and it can be appropriately selected depending on the material of the wetted parts of the tank 101, the type of resist composition to be manufactured, etc. Generally, a time of 0.1 seconds to 48 hours is preferred for cleaning the tank.

[0037] The cleaning solution may be circulated within the manufacturing apparatus (hereinafter also referred to as "circulation cleaning") and then discharged in predetermined amounts in multiple stages for the purpose of cleaning the valve 133. It is preferable not to reuse the discharged cleaning solution.

[0038] The number of washes, wash time, and amount of wash solution used can be arbitrarily set according to the resin composition, solvent composition, viscosity, etc., contained in the first resist composition manufactured before the wash process.

[0039] The number of washes should be such that, in the analysis step described later, it is detected that the component concentration of the resist composition in the washing solution is less than 300 ppb. In other words, in the embodiment of the present invention, washing is repeated until it is detected that the component concentration of the resist composition in the washing solution is less than 300 ppb. Regarding the specific number of washes, for example, two or more washes are preferable, and three or more washes are more preferable. There is no particular upper limit on the number of washes, but from the viewpoint of reducing manufacturing time and manufacturing costs, 20 washes or less is preferable, 10 washes or less is more preferable, and 5 washes or less is even preferable. A resist composition with better defect suppression performance is more likely to be obtained when the number of washes is three or more.

[0040] (Pre-cleaning) The cleaning step in the embodiments of the present invention may include a pre-cleaning step, and it is preferable that the pre-cleaning step be included after removing the filtration filter from the manufacturing apparatus and before cleaning the manufacturing apparatus. The pre-cleaning process involves further disassembling the disassemblable components of the manufacturing equipment from which the filtration filter has been removed, and then pre-cleaning the disassembled components of the manufacturing equipment. Examples of disassemblable components include piping, filters, pumps, valves, etc. Pre-cleaning is preferably performed by spraying, rinsing, or rinsing the disassembled components of the manufacturing equipment using a wash bottle filled with cleaning solution. Alternatively, it is preferable to immerse the components in a container, washing tank, or the like. By including a pre-cleaning step in the cleaning process, the connecting parts of the components can be thoroughly cleaned, thereby improving the cleanliness of the manufacturing equipment.

[0041] The pre-cleaning time and the amount of cleaning solution used can be arbitrarily set according to the resin composition, solvent composition, viscosity, etc., contained in the first resist composition manufactured before the cleaning process. In the pre-washing process, it is preferable to continue shower washing of the components of the manufacturing equipment until no organic components can be visually confirmed to be attached. There are no particular time constraints, but for example, the shower washing time is preferably 10 seconds or more, more preferably 20 seconds or more, and even more preferably 30 seconds or more. Furthermore, from the viewpoint of manufacturing time and manufacturing cost, the shower washing time is preferably 10 minutes or less, more preferably 8 minutes or less, and even more preferably 5 minutes or less.

[0042] It is preferable that the disassembled components of the manufacturing apparatus be pre-cleaned in a pre-cleaning process, and then assembled into a manufacturing apparatus with all parts except the filtration filter, and then cleaned in the cleaning process described above.

[0043] (Cleaning solution) The cleaning solution used in the cleaning step in the embodiments of the present invention is not particularly limited, and known cleaning solutions can be used. Examples of cleaning solutions include alcohols; ether-based organic solvents such as alkylene glycol monoalkyl ether carboxylates and alkylene glycol monoalkyl ethers; ketone-based organic solvents such as cyclic lactones (preferably having 4 to 10 carbon atoms) and monoketone compounds that may have a ring (preferably having 4 to 10 carbon atoms); and ester-based organic solvents such as alkyl lactate, alkyl alkoxypropionate, alkylene carbonate, alkyl alkoxyacetate, and alkyl pyruvate.

[0044] The cleaning solution may include alcohols such as propanol (IPA), butanol (nBA), iAA (methyl isobutylcarbinol), and MIBC (methyl isobutylcarbinol); glycol-based organic solvents such as PGME (propylene glycol monomethyl ether) and PGMEA (propylene glycol monomethyl ether acetate); hydrocarbon-based organic solvents such as CyHe (cyclohexane); and DBCPN (cyclopentanone). It is preferable to contain at least one selected from the group consisting of ether-based organic solvents such as dimethylacetal, EL (ethyl lactate), and HBM (methyl 2-hydroxyisobutyrate); ester-based organic solvents such as GBL (γ-butyrolactone); and ketone-based organic solvents such as DMSO (dimethyl sulfoxide), EC (ethylene carbonate), PC (propylene carbonate), NMP (1-methyl-2-pyrrolidone), MAK (2-heptanone), cyclopentanone, cyclohexanone, acetone, and MEK (methyl ethyl ketone). It is more preferable to contain at least one selected from the group consisting of PGMEA, NMP, PGME, nBA, GBL, MIBC, EL, DMSO, MAK (2-heptanone), cyclohexanone, acetone, and MEK. The cleaning solution may be used individually or in combination of two or more types.

[0045] In addition to the above, other examples of cleaning solutions include alcohols such as methanol, ethanol, methoxyethanol, butoxyethanol, methoxypropanol, and ethoxypropanol; glycol-based organic solvents such as dipropylene glycol monomethyl ether, dipropylene glycol, and ethylene glycol monobutyl ether; ketone-based organic solvents such as MIBK (methyl isobutyl ketone) and DIBK (diisobutyl ketone); ether-based organic solvents such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ester-based organic solvents such as ethyl acetate and ethyl cellosolve acetate; aromatic compounds such as benzene, toluene, and xylene; and chlorinated hydrocarbons such as dichloromethane, dichloroethane, dichloroethylene, and trichloroethylene.

[0046] Furthermore, a solution containing water added to the above-mentioned organic solvent may be used as the cleaning solution. Adding water can facilitate the cleaning of water-soluble organic impurities that are difficult to remove with cleaning using only the organic solvent.

[0047] The cleaning solution preferably contains at least one selected from the group consisting of glycol-based organic solvents, ester-based organic solvents, lactone-based organic solvents, and ketone-based organic solvents, more preferably a glycol-based organic solvent, and may also contain propylene glycol monomethyl ether acetate.

[0048] The cleaning time and the amount of cleaning solution used can be arbitrarily set according to the resin composition, solvent composition, viscosity, etc., contained in the first resist composition manufactured before the cleaning process.

[0049] <Analysis process> The analysis step in the embodiment of the present invention is the step of taking out the cleaning solution used in the cleaning step and analyzing it. There are no particular restrictions on the method of extracting the cleaning solution, but for example, after the cleaning process is completed, the drained cleaning solution can be taken into a sample container and extracted. The cleaning solution may be partially or entirely extracted. If only a portion is extracted, the remaining cleaning solution in the manufacturing equipment can be reused in further cleaning processes.

[0050] In the analysis step of the embodiment of the present invention, for example, the cleaning solution used in the cleaning step is collected. The collected cleaning solution is analyzed without concentration. There may be a step (concentration step) in which the concentration of the resist composition components contained in the cleaning solution is increased before analysis, but it is preferable to analyze without concentration in order to shorten the analysis time and prevent contamination by other components. By performing the analysis without concentration, it is possible to prevent contamination by other components. If there is a possibility that impurities are mixed into the resist composition being manufactured, problems may arise such as a significant decrease in the efficiency of factor analysis when a problem occurs.

[0051] The method for analyzing the component concentrations of the resist composition contained in the cleaning solution is not particularly limited and includes, for example, liquid chromatography, gas chromatography, Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible spectroscopy (UV-Vis). In this embodiment, it is preferable to perform the analysis of the component concentrations of the resist composition in the analysis step using a liquid chromatography method, as this allows for highly sensitive detection. In other words, it is preferable to analyze the washing solution using liquid chromatography in the analysis process. The component concentrations of the resist composition contained in the washing solution can be analyzed using known methods such as liquid chromatography, gas chromatography, Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible spectroscopy (UV-Vis).

[0052] In the method for producing a resist composition according to an embodiment of the present invention, prior to the manufacturing process described later, the washing step and the analysis step are each performed at least once until the concentration of the resist composition components contained in the washing solution in the analysis step is less than 300 ppb. If the concentration of the components of the first resist composition contained in the cleaning solution during the analysis step is greater than 300 ppb, the cleaning step is performed again. After performing the further cleaning step at least once, the cleaning step and analysis step are repeated until the concentration of the components of the first resist composition contained in the cleaning solution removed from the manufacturing apparatus is 300 ppb or less. Once the concentration of the components of the first resist composition contained in the cleaning solution is less than 300 ppb, the manufacturing step for producing the second resist composition can be initiated. The concentration of the components of the first resist composition contained in the cleaning solution is preferably 250 ppb or less, more preferably 200 ppb or less, even more preferably 150 ppb or less, even more preferably 130 ppb or less, and particularly preferably 120 ppb or less, and most preferably substantially absent (below the detection limit of the measuring device). According to the method for producing a resist composition that includes the above steps, a resist composition having excellent defect suppression performance can be obtained.

[0053] (Components of the resist composition contained in the cleaning solution) The components of the first resist composition contained in the cleaning solution that are analyzed in the analysis step are components different from the organic solvent contained in the cleaning solution, and are intended to be the components that make up the first resist composition manufactured before cleaning, and the reaction products of each component, with a particular emphasis on organic components. Specifically, the components of the resist composition that are analyzed in the analysis step include the above-mentioned base material component (A) (hereinafter also referred to as "component (A)"), acid generator component (B) (hereinafter also referred to as "component (B)"), organic solvent component (S) (hereinafter also referred to as "component (S)"), compound (E) (hereinafter also referred to as "component (E)"), acid diffusion control component (D) (hereinafter referred to as "component (D)"), fluorine-based additive component (hereinafter referred to as "component (F)"), etc.

[0054] When manufacturing a new second resist composition, if organic components different from those specified in the design are mixed in, it is anticipated that unintended aggregation or reaction of components may occur in the second resist composition, potentially leading to defects.

[0055] <Manufacturing process for the second resist composition> The manufacturing process in the embodiment of the present invention is to manufacture a resist composition by attaching another filter to a manufacturing apparatus from which a filter has been removed.

[0056] In this process, a second resist composition is manufactured using a cleaned manufacturing apparatus. There are no particular restrictions on the method for preparing the second resist composition, but the components constituting the second resist composition are introduced into the manufacturing apparatus, and other components are mixed in as needed. The mixing of the components constituting the second resist composition can be carried out under known conditions. The second resist composition produced in this process may be the same as the first resist composition produced before the cleaning process, and the second resist composition produced in this process and the first resist composition produced before the cleaning process may have the same or different compositions.

[0057] It is preferable to use an unused filter as the other filter to be installed in this process. Since it is difficult to remove organic impurities from used filters even after repeated washing processes, using an unused filter as the other filter prevents the contamination of the second resist composition with impurities, thereby obtaining a high-purity resist composition.

[0058] By attaching another filtration filter to the filter of the manufacturing apparatus, the prepared resist composition can be passed through the filter 140, which is equipped with the filter, and foreign matter can be removed from the resist composition by passing it through the filter. The pore size of the filter used in this manufacturing apparatus can be appropriately selected according to the required quality level of the product (resist composition). For example, a filter with a pore size of 20 nm or less may be used, and if an even higher quality level is required, a filter with a pore size of 10 nm or less can be used.

[0059] Furthermore, there are no particular restrictions on the material of the filter used in the manufacturing apparatus. Examples include materials commonly used for filtering resist compositions, such as fluorocarbon, nylon, polyester, hydrocarbon, and polyimide materials. However, filters made of fluorocarbon materials, such as Teflon (registered trademark), hydrocarbon materials such as polyethylene and polypropylene, or nylon and polyimide are preferably used.

[0060] <Other processes> The method for producing the resist composition described above may include other steps, within the scope of achieving the effects of the present invention. These other steps are not particularly limited, but examples include a step in the cleaning step to remove residual cleaning solution from the inside or surface of the component using compressed gas, an ultrasonic cleaning step for the disassemblable component, and a calibration step and a data analysis step in the analysis step.

[0061] According to the method for manufacturing a resist composition according to the embodiment of the present invention described above, it is possible to manufacture a resist composition with further reduced organic impurities. For example, by forming a resist film using this resist composition, defect occurrence can be suppressed, and the electrical properties of semiconductor devices and the like can be improved and stabilized.

[0062] [Defect suppression performance] A resist composition produced by the method for producing a resist composition according to an embodiment of the present invention can form a resist film that suppresses defect occurrence. The defect suppression performance (defect suppression performance) of the resist composition according to the embodiment of the present invention can be evaluated by measuring the number of defects in the resist film on a substrate (support) formed with the resist composition. The defect suppression performance (defect suppression performance) of the resist composition according to the embodiment of the present invention can also be evaluated by measuring the number of defects on a pattern formed by exposing the resist film to a predetermined light source and developing it with a predetermined developer. Pattern defects can be evaluated using known methods.

[0063] The defect suppression performance of a resist composition obtained by a method for manufacturing a resist composition according to an embodiment of the present invention is determined more specifically by forming a resist film on a support using the resist composition of the above embodiment and measuring the number of defects in the resist film on the support. For example, when a silicon wafer with a diameter of 300 mm is used as the support, the number of defects per silicon wafer is preferably less than 150, and more preferably less than 100. The resist film can be formed by known methods.

[0064] The various materials used in the resist compositions of the embodiments described above (for example, resist solvent, developer, rinse solution, anti-reflective film forming composition, top coat forming composition, etc.) are preferably free from impurities such as metals, metal salts containing halogens, acids, alkalis, sulfur atoms, or phosphorus atoms. Examples of impurities containing metal atoms include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, or salts thereof. The content of impurities in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt or less, particularly preferably 10 ppt or less, and most preferably substantially free (below the detection limit of the measuring device).

[0065] As for the method of measuring the number of defects, methods commonly used for measuring the number of defects on a substrate can be used. Specifically, examples include measuring the number of defects using defect inspection equipment such as the KLA-Tencor dark-field defect inspection system "SP-5 (product name)".

[0066] While fewer defects are desirable for optimal performance, it is practically difficult to eliminate extremely small defects entirely. However, it is preferable that the number of defects larger than 50 nm be less than 150, more preferably less than 100, and even more preferably less than 70. The above criteria can be appropriately selected depending on the application of the resist composition, i.e., the pattern shape, line width, layout, etc.

[0067] As described above, the method for producing a resist composition according to the embodiment of the present invention reduces impurities in the resist composition and makes it possible to produce a resist composition that is excellent in suppressing the occurrence of defects in the resist film. [Examples]

[0068] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0069] <Synthesis of polymer compound A-1>

[0070] A polymer compound was synthesized by radical polymerization using monomers that derive the constituent units of polymer compound (A)-1 shown below, in a predetermined molar ratio. For the obtained polymer compound, the carbon-13 nuclear magnetic resonance spectrum ( 13 The copolymerization composition ratio (molar ratio of each constituent unit in the polymer compound) of the polymer compound, determined by 13C-NMR, and the weight-average molecular weight (Mw) and molecular weight dispersion (Mw / Mn) in terms of standard polystyrene, determined by GPC measurement, are also shown.

[0071] [ka]

[0072] [Examples 1 and 2] <Preparation of Resist Composition 1> Using a resist composition manufacturing apparatus equipped with a filter including a filtration filter as shown in Figure 1, a preparation tank, piping, a pump, and a valve, the components shown in Table 1 were mixed and dissolved in the preparation tank, sensitivity and viscosity were adjusted by a predetermined method, and then the resist composition 1 was prepared (manufactured) by circulating it through the apparatus and filtering it with the filter.

[0073] [Table 1]

[0074] In Table 1, each abbreviation has the following meaning. The numbers in brackets [] in Table 1 indicate the amount of each component, and the unit of the amount is parts by mass.

[0075] (A)-1: A base component consisting of a polymer compound represented by the above chemical formula (A)-1. (B)-1: An acid generating agent component consisting of the compound represented by the following chemical formula (B)-1. (D)-1: An acid diffusion control agent component consisting of the compound represented by the following chemical formula (D)-1. (E)-1: Salicylic acid (S)-1: A mixed solvent in a mass ratio of propylene glycol monomethyl ether acetate (PGMEA) / propylene glycol monomethyl ether (PGME) = 20 / 80.

[0076] [ka]

[0077] <Cleaning of resist composition manufacturing equipment and analysis of cleaning solution> After removing the filtration filter from the manufacturing equipment, all disassemblable components, specifically the supply piping, pump, filter, circulation piping, and valves, were disassembled and pre-cleaned. The manufacturing equipment was then reassembled, and the interior was cleaned by circulating cleaning solution through the resist composition manufacturing equipment (circulation cleaning). The specific procedure is as follows:

[0078] 1. The filtration filter was removed from the resist composition manufacturing apparatus, and the disassemblable components (supply piping, pump, filter, circulation piping, valve) were disassembled. 2. Further disassembling of the components was performed, and the inside of the components and the pipe connections were pre-cleaned using a wash bottle filled with cleaning solution. 3. The components of the manufacturing apparatus, excluding the filtration filter, were reassembled. 4. The cleaning solution was introduced into the tank through the supply port, and the cleaning solution was circulated to clean the manufacturing equipment from which the filtration filter had been removed (circulation cleaning). 5. The cleaning solution was extracted and analyzed.

[0079] For the cleaning solution, acetone was used for the preliminary cleaning of disassemblable components, and propylene glycol monomethyl ether acetate (PGMEA) was used for the circulation cleaning after the manufacturing equipment was reassembled. For the preliminary cleaning of disassemblable components, a shower wash was performed using a wash bottle filled with acetone until no organic components could be visually confirmed to be attached. For the circulation cleaning of the manufacturing equipment after the filtration filter was removed, 10% by volume of the tank capacity was added, and the inside was circulated for 15 minutes to clean it. The cleaning solution used for the circulation cleaning was collected in a glass bottle, and the content of organic components in the cleaning solution was measured and calculated using the analytical method described below. Step 4 of the above cleaning process was repeated the number of times (number of washes) indicated in Table 2 until the analysis result of the organic components in the cleaning solution was less than 300 ppb.

[0080] (Analysis method) The amount of organic components contained in the washing solution after washing was measured using a liquid chromatography apparatus manufactured by Thermo Fisher Scientific. A combination of ultrapure water and an organic solvent was used as the mobile phase.

[0081] <Preparation of Resist Composition 2> After the cleanliness of the manufacturing apparatus was confirmed through the above process, a new filter was installed, and using the cleaned resist composition manufacturing apparatus, the components shown in Table 1 were mixed and dissolved to prepare (manufacture) resist composition 2, which had the same composition as resist composition 1. The preparation (manufacturing) was carried out using the same procedure as for resist composition 1.

[0082] <Resist film formation> Using Tokyo Electron's "CLEAN TRACK LITHIUS Pro Z (product name)," the resist composition prepared in <Preparation of Resist Composition 2> was rotary coated onto a 300 mm diameter silicon wafer (hereinafter referred to as "wafer") at 1500 rpm, and then the wafer was dried to form a resist film.

[0083] <Evaluation of defect suppression performance of resist compositions> The defect suppression performance of the resist film formed by the above-described <formation of resist film> was evaluated using the following method. The number of defects in the resist film on this wafer was measured using KLA-Tencor's "SP-5 (product name)" and evaluated according to the following evaluation criteria. The measurement was limited to defects with a size of 50 nm or larger. The results are shown in Table 2. A: Less than 30 defects B: Number of defects is 30 or more, but less than 70. C: Number of defects is 70 or more, but less than 100. D: Number of defects is 100 or more

[0084] [Comparative Examples 1 and 2] The same procedure as in Example 1 was followed, except that disassembly and cleaning were not performed, and the inside of the manufacturing equipment was cleaned by circulating cleaning with a cleaning solution, and the number of cleaning cycles was changed as shown in Table 2 to produce the resist composition. [Comparative Example 3] The same procedure as in Example 1 was followed, except that the number of washes was changed as shown in Table 2 to produce the resist composition.

[0085] [Table 2]

[0086] These results showed a correlation between the concentration of organic components in the cleaning solution and the number of defects in the resist film formed by the resist composition, confirming that the cleanliness of the manufacturing equipment affects the quality of the resist composition. It was found that by controlling the concentration of organic components in the cleaning solution to less than 300 ppb, it is possible to suppress the number of defects in the resist film formed by the resist composition to less than 100. [Explanation of Symbols]

[0087] 100 Manufacturing equipment 101 Tank 102 Container 109 Circulation piping 110 Supply piping 131, 132, 133 valves 140 Filtration Machine 151 pump 161 Supply port

Claims

1. A step of manufacturing a resist composition using a manufacturing apparatus equipped with a filter that includes a filter, and then removing the filter from the manufacturing apparatus, A cleaning step in which the manufacturing apparatus from which the filtration filter has been removed is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, A manufacturing process for manufacturing a resist composition involves attaching another filter to the manufacturing apparatus from which the aforementioned filter has been removed, A method for producing a resist composition having the following characteristics: The other filtration filter in the manufacturing process is an unused filtration filter. Prior to the manufacturing process, the washing process and the analysis process are each performed at least once until the concentration of the resist composition components contained in the washing solution in the analysis process is less than 300 ppb. A method for producing a resist composition.

2. In the analysis step described above, the washing solution is analyzed using liquid chromatography. A method for producing the resist composition according to claim 1.

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