Analytical method and method for producing resist composition

Abstract

This invention provides an analytical method that allows for the simple and highly accurate evaluation of the cleanliness of a resist composition manufacturing apparatus. [Solution] An analytical method comprising a cleaning step of cleaning a manufacturing apparatus for manufacturing a resist composition using a cleaning solution, and an analytical step of taking out the cleaning solution used in the cleaning step and analyzing it, wherein the analytical step detects, using liquid chromatography equipped with a corona detector, that the concentration of components of the resist composition contained in the cleaning solution in the analytical step is less than 200 ppb without performing a concentration step.

Description

[Technical Field]

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

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

[0003] In the production of semiconductor elements and liquid crystal display elements, advances in lithography technology have led to rapid progress in pattern miniaturization and multilayered substrates. Along with the progress of miniaturization of resist patterns, resist materials are required to improve various lithography properties and also to suppress the occurrence of defects in resist films. Along with this, 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 method for producing 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 a purified resist composition produced by the production method, the method includes the step (i) of filtering the resist composition through a filter having a porous structure in which adjacent spherical cells communicate with each other. A method for producing a purified resist composition is described. [Prior Art Document] [Patent Document]

[0005] [Patent Document 1] Japanese Patent No. 7195418 [Summary of the Invention] [Problems that the invention aims to solve]

[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.

[0007] Therefore, the object of the present invention is to provide an analytical method that can easily and accurately evaluate the cleanliness of a resist composition manufacturing apparatus. Furthermore, the present invention 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]

[0008] Our investigations have revealed that organic components originating from previous manufacturing lots of resist compositions remain in the resist composition manufacturing equipment and are mixed into the next resist composition produced, which is one of the causes of defects in resist films. Furthermore, the possibility of organic components from previous manufacturing lots being mixed into the next resist composition can lead to problems such as a significant decrease in the efficiency of factor analysis when a problem occurs. Therefore, it was found that maintaining a high level of cleanliness within the manufacturing equipment is necessary in order to produce high-quality resist compositions that suppress defect occurrence in the resist film.

[0009] One possible way to evaluate the cleanliness of a manufacturing apparatus is to analyze the concentration of components in the resist composition contained in the cleaning solution used to clean the apparatus. However, conventional analytical methods cannot detect trace amounts of components in the cleaning solution with high sensitivity, making it difficult to confirm whether the cleanliness of the manufacturing apparatus is sufficient. Therefore, complicated pretreatment such as concentrating the cleaning solution to be analyzed is required beforehand, which has been a major obstacle to establishing a process for easily manufacturing high-quality resist compositions. Therefore, the present inventors have found a manufacturing method for producing a high-quality resist composition without pre-treatment such as concentration of the washing solution used for analysis, and an analytical method that can easily and accurately evaluate the cleanliness of a resist composition manufacturing apparatus, thereby completing the present invention.

[0010] Therefore, one aspect of the present invention is: A cleaning step in which the manufacturing equipment for producing the resist composition is cleaned using a cleaning solution, The process includes an analysis step of taking out the cleaning solution used in the cleaning step and analyzing it, The analysis described above is an analytical method that detects, using liquid chromatography equipped with a corona detector, that the component concentration of the resist composition contained in the washing solution in the analytical step is less than 200 ppb without performing a concentration step.

[0011] Another aspect of the present invention is: A first manufacturing step of manufacturing a first resist composition using a manufacturing apparatus for manufacturing resist compositions, A cleaning step in which the manufacturing apparatus is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, The process includes a second manufacturing step of manufacturing a second resist composition using the aforementioned manufacturing apparatus, The present invention relates to a method for producing a resist composition, wherein, prior to the second manufacturing step, the washing step and the analysis step are each performed at least once until the analysis detects that the concentration of the components of the first resist composition contained in the washing solution in the analysis step is less than 200 ppb without performing a concentration step. [Effects of the Invention]

[0012] According to one aspect of the present invention, the cleanliness of a resist composition manufacturing apparatus can be evaluated simply and with high accuracy without performing any pretreatment such as concentration on the cleaning solution used for analysis. Further, according to the method for producing a resist composition according to another aspect of the present invention, it is possible to produce a resist composition in which impurities are reduced and the occurrence of defects in a resist film is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of a production apparatus for producing a resist composition. MODES FOR CARRYING OUT THE INVENTION

[0014] In the present specification and claims, "mass%" and "weight%" are synonymous, "parts by mass" and "parts by weight" are synonymous, and "mass ratio" and "weight ratio" are synonymous.

[0015] [Analysis Method] The analysis method according to an embodiment of the present invention comprises: a washing step of washing a production apparatus for producing a resist composition using a washing liquid; and an analysis step of taking out and analyzing the washing liquid after being used in the washing step, the analysis detects that the component concentration of the resist composition contained in the washing liquid in the analysis step is less than 200 ppb without performing a concentration step, using liquid chromatography equipped with a corona detector.

[0016] The inventors have found that when the content of components of the resist composition contained in the washing liquid after the washing step is less than 200 ppb, the cleanliness of the production apparatus is at a sufficient level, the amount of impurities mixed into the newly produced resist composition is reduced, and the occurrence of defects in the resist film can be suppressed. The inventors have also found that liquid chromatography equipped with a corona detector can detect component concentrations of a resist composition on the ppb order with high sensitivity, and have arrived at the finding that it is possible to detect that the component concentration of the resist composition contained in the washing liquid is less than 200 ppb without performing a concentration step of the washing liquid. This makes it possible to easily and highly accurately evaluate the cleanliness of manufacturing equipment without performing a concentration step for concentrating the cleaning liquid, and to establish a process for manufacturing a high-quality resist composition.

[0017] <Cleaning Step> In the cleaning step according to an embodiment of the present invention, manufacturing equipment for producing a resist composition is cleaned using a cleaning liquid.

[0018] (Resist Composition) In the analysis method according to an embodiment of the present invention, the resist composition produced by the manufacturing apparatus 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 a polymer, 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. Further, 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)").

[0019] The component (A) is not particularly limited, and those that have been conventionally proposed as base components for resist compositions can be used.

[0020] 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 of these. (A) For example, the base components described in Japanese Patent Publication No. 2025-178097, International Publication No. 2024 / 053689, Japanese Patent Publication No. 2023-010711, and Japanese Patent Publication No. 2004-43777 can be used as components. (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.

[0021] (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).

[0022] 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.

[0023] 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.

[0024] 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).

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] (manufacturing equipment) The manufacturing apparatus for producing the resist composition used in the embodiments of the present invention (hereinafter also referred to as the "manufacturing apparatus") is not particularly limited as long as it is capable of producing the resist composition described later. The manufacturing apparatus may, for example, include a tank, piping, pump, supply port, valve, and a filter including a filtration filter.

[0030] Figure 1 is a schematic diagram showing one embodiment of a manufacturing apparatus for producing a resist composition. The manufacturing apparatus 100 includes a tank 101, which has a supply port 161 for supplying resist composition material. The manufacturing apparatus 100 may further include a filter 140 including a filtration filter. The tank 101 and the filter 140 including 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. In Figure 1, the manufacturing apparatus 100 includes a tank 101, but the manufacturing apparatus is not limited to this and can be used in the analytical method according to the embodiment of the present invention.

[0031] 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 via a circulation pipe 109 connecting the filter 140 and the tank 101, by switching valves 131 and 133 provided in the circulation pipe 109.

[0032] (Cleaning method) In the analytical method according to the embodiment of the present invention, the method for cleaning the manufacturing apparatus is not particularly limited, and known methods can be used. An example of a method for cleaning the manufacturing apparatus will be explained with reference to Figure 1. The arrows in Figure 1 indicate the direction of liquid flow. In the case of the manufacturing apparatus illustrated in Figure 1, a method can be used in which cleaning liquid is supplied into the manufacturing apparatus from a supply port 161 provided in the tank 101, valve 133 is closed, and then valves 132 and 131 are opened so that the cleaning liquid flows in the direction of liquid flow, and the cleaning liquid is transferred through the supply pipe 110 and the circulation pipe 109 to clean the manufacturing apparatus. An example of a cleaning method will be explained in more detail using the manufacturing apparatus 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 tank 101 in the manufacturing apparatus. The amount of cleaning solution used for one cleaning cycle is preferably 5% or more by volume, more preferably 10% or more by volume, and even more preferably 15% or more by volume, relative to the capacity of the tank 101, 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 pipe 110, pump 151, filter 140, and circulation pipe 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, valve 132, pump 151, filter 140, circulation piping 109, valve 131, etc. 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 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 200 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 200 ppb. Specifically, the number of washes is preferably two or more, and more preferably three or more. There is no particular upper limit on the number of washes, but from the viewpoint of reducing manufacturing time and manufacturing costs, it is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less. If the number of washes is three or more, the cleanliness of the manufacturing equipment will be higher, and it will be easier to obtain a resist composition with excellent defect suppression performance.

[0040] (Pre-cleaning) The cleaning step in the embodiments of the present invention may include a pre-cleaning step, and it is preferable to include a pre-cleaning step before cleaning the manufacturing equipment. The pre-cleaning process involves further disassembling the detachable components of the manufacturing equipment and pre-cleaning the disassembled components of the manufacturing equipment. Examples of detachable components include piping, filters, pumps, valves, etc. Pre-cleaning is preferably performed by showering, 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 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] In embodiments of the present invention, it is preferable to perform a preliminary cleaning of the components of the manufacturing apparatus that have been disassembled in the preliminary cleaning step, then assemble the manufacturing apparatus and perform the cleaning in the cleaning step described above.

[0043] (Cleaning solution) In the analytical method according to the embodiment of the present invention, the cleaning solution 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 in addition to the above-mentioned organic solvent may be used as the cleaning solution. The addition of 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 resist composition.

[0049] <Analysis process> In the analytical method according to an embodiment of the present invention, the analytical step involves taking out the cleaning solution used in the cleaning step and analyzing it. There are no particular restrictions on the method of removing the cleaning solution. The cleaning solution may be partially or entirely removed. If only a portion is removed, the remaining cleaning solution in the manufacturing equipment can be reused in further cleaning processes.

[0050] In the analysis process, for example, the cleaning solution used in the washing process may be collected. The collected cleaning solution is analyzed without concentration. By analyzing without concentration, contamination by other components can be prevented, and the analysis time can be shortened, resulting in a simpler analysis method.

[0051] In the embodiment of the present invention, the analysis involves detecting, using liquid chromatography equipped with a corona detector, that the component concentration of the resist composition (first resist composition) contained in the washing solution during the analysis step is less than 200 ppb without performing a concentration step.

[0052] As a result of the inventors' investigation, it was found that if the components of the resist composition contained in the cleaning solution after the above cleaning process are less than 200 ppb, the cleanliness of the manufacturing equipment is at a sufficient level, the amount of impurities mixed into the newly manufactured resist composition (second resist composition) is reduced, and the occurrence of defects in the resist film can be suppressed.

[0053] Conventional analytical methods have employed liquid chromatography, gas chromatography, NMR, ultraviolet-visible spectrophotometers (UV-Vis), and Fourier transform infrared spectrophotometers (FT-IR) equipped with UV detectors. However, when the concentration of components of the resist composition contained in the washing solution is extremely small, on the order of ppb, these analytical methods fall below the detection limit of the analytical instruments, making it difficult to analyze the washing solution with sufficient accuracy. Therefore, when analyzing a cleaning solution with a component concentration of a resist composition on the order of ppb using conventional analytical methods, it is necessary to concentrate the cleaning solution beforehand so that the component concentration exceeds the detection limit of the analytical instrument. Such complex pretreatment processes, including concentration steps, have been a major obstacle to establishing a simple process for manufacturing high-quality resist compositions. Furthermore, the possibility of impurities being present in the manufactured resist composition can significantly reduce the efficiency of troubleshooting when problems occur.

[0054] The inventors then discovered that liquid chromatography equipped with a corona detector can detect even ppb-order component concentrations of resist compositions with high sensitivity, and conceived the idea that it is possible to detect that the component concentration of the resist composition contained in the washing solution is less than 200 ppb without performing a washing solution concentration step. This makes it possible to evaluate the cleanliness of the manufacturing equipment simply and accurately without performing a concentration step to concentrate the cleaning solution, and to establish a process for manufacturing high-quality resist compositions.

[0055] Furthermore, the components of the resist composition contained in the cleaning solution that are analyzed in the analysis process are components different from the organic solvent contained in the cleaning solution, and are intended to be the individual components that make up the resist composition manufactured before cleaning, and the reaction products of each of those components, with a particular emphasis on organic components. Specifically, the components of the resist composition that are analyzed in the analysis process 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)"), and other organic components.

[0056] 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, leading to the occurrence of defects.

[0057] In embodiments of the present invention, the liquid chromatography is not particularly limited as long as it can separate the components of the resist composition contained in the washing solution. For example, a liquid chromatography apparatus such as Thermo Fisher Scientific's "Vanquish" (trade name) can be used. The measurement conditions, such as the column used, flow rate, amount of washing solution injected, mobile phase, measurement time, and column temperature, are not particularly limited and may be set arbitrarily according to the components of the resist composition contained in the washing solution.

[0058] The washing solution injected into the liquid chromatography is the same washing solution used in the washing step described above, without undergoing a concentration step. In this embodiment of the present invention, the concentration step refers to a process of concentrating the washing solution by operations such as heating or reduced pressure, and does not include cases where the organic solvent contained in the washing solution spontaneously evaporates between the time the washing solution is removed from the manufacturing apparatus and the time it is injected into the liquid chromatography.

[0059] In embodiments of the present invention, the corona detector is not particularly limited as long as it can detect that the component concentration of the resist composition contained in the washing solution is less than 200 ppb. For example, a liquid chromatography system such as Thermo Fisher Scientific's "Vanquish" (trade name) can be used.

[0060] Since corona detectors detect non-volatile compounds, the components detected as part of the resist composition contained in the cleaning solution are typically resins such as component (A). However, the components detected by corona detectors are not limited to these.

[0061] In an embodiment of the present invention, if the component concentration of the resist composition contained in the cleaning solution during the analysis step is 200 ppb or more, the cleaning step is performed again. After performing the further cleaning step at least once, the cleaning step and the analysis step are repeated any number of times until the component concentration of the resist composition contained in the cleaning solution removed from the manufacturing apparatus is less than 200 ppb.

[0062] The concentration of the resist composition components in the washing solution, as detected by liquid chromatography equipped with a corona detector, is preferably less than 200 ppb, more preferably less than 100 ppb, even more preferably less than 60 ppb, and most preferably substantially absent (below the detection limit of the corona detector).

[0063] As explained above, the analytical method including the above steps allows for the simple and highly accurate evaluation of the cleanliness of the manufacturing equipment without the need for a concentration step to concentrate the cleaning solution, thereby establishing a process for producing high-quality resist compositions.

[0064] <Other processes> The analysis method according to the embodiment of the present invention may include other steps, within the scope of achieving the effects of the present invention. Other steps are not particularly limited, but examples include a step in the cleaning step to remove cleaning solution remaining inside or on the surface of the component using compressed gas, an ultrasonic cleaning step for the disassemblable component, and a calibration step, a data analysis step, etc., in the analysis step.

[0065] [Method for manufacturing a resist composition] A method for producing a resist composition according to another embodiment of the present invention is: A first manufacturing step of manufacturing a first resist composition using a manufacturing apparatus for manufacturing resist compositions, A cleaning step in which the manufacturing apparatus is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, The process includes a second manufacturing step of manufacturing a second resist composition using the aforementioned manufacturing apparatus, Prior to the second manufacturing step, the washing step and the analysis step are each performed at least once until the analysis detects that the concentration of the components of the first resist composition contained in the washing solution in the analysis step is less than 200 ppb without performing a concentration step.

[0066] The inventors discovered that by detecting that the component concentration of the first resist composition contained in the washing solution is less than 200 ppb without performing a concentration step, and confirming the cleanliness of the manufacturing equipment, before manufacturing the second resist composition, it is possible to easily and effectively prevent impurities from contaminating the resist composition. As a result, it became possible to manufacture a resist composition with reduced impurities and suppressed defects in the resist film.

[0067] <First manufacturing process> In a manufacturing method according to an embodiment of the present invention, the first manufacturing step is to manufacture a first resist composition using a manufacturing apparatus for manufacturing a resist composition. The manufacturing apparatus for manufacturing the resist composition is not particularly limited and may be the same as that described in (manufacturing apparatus) in the [analysis method] above.

[0068] There are no particular limitations on the method for preparing the first resist composition; the components constituting the first resist composition may be introduced into a manufacturing apparatus, and other components may be mixed in as needed. The mixing of the components constituting the first resist composition can be carried out under known conditions.

[0069] The first resist composition produced in this process is not particularly limited as long as it can form a resist film. For example, a resist composition containing a polymer and an organic solvent can be used, and is similar to the one described in (resist composition) in the [analytical method] above.

[0070] <Washing process> In the manufacturing method according to an embodiment of the present invention, the cleaning step involves cleaning the manufacturing apparatus with a cleaning solution. Known cleaning methods can be used, and a method similar to that described in (Cleaning Method) in the above [Analysis Method] may be used. Furthermore, there are no particular limitations on the cleaning solution used in the cleaning step, and known cleaning solutions can be used, such as those similar to those described in (Cleaning Solution) in the above [Analysis Method].

[0071] <Analysis process> In the manufacturing method according to an embodiment of the present invention, the analysis step involves taking out the cleaning solution used in the cleaning step and analyzing it. There are no particular restrictions on the method of removing the cleaning solution. The cleaning solution may be partially or entirely removed. If only a portion is removed, the remaining cleaning solution in the manufacturing equipment can be reused in further cleaning processes.

[0072] In the analysis step, for example, the cleaning solution may be collected from the cleaning solution used in the washing step.

[0073] In the manufacturing method according to an embodiment of the present invention, prior to the second manufacturing step described later, the washing step and the analysis step are each performed at least once until the analysis detects that the component concentration of the first resist composition contained in the washing solution in the analysis step is less than 200 ppb without performing a concentration step.

[0074] If the concentration of components of the first resist composition contained in the cleaning solution detected by analysis is less than 200 ppb, the cleanliness of the manufacturing equipment is at a sufficient level, and the amount of impurities mixed into the second resist composition (described later) is reduced. As a result, a resist composition in which the occurrence of defects in the resist film is suppressed can be manufactured. Furthermore, problems such as a significant decrease in the efficiency of factor analysis when problems occur during the manufacturing process of the resist composition can be prevented.

[0075] If the concentration of the components of the first resist composition in the cleaning solution during the analysis step is greater than 200 ppb, the cleaning step is repeated. After performing the further cleaning step at least once, the cleaning and analysis steps are repeated until the concentration of the components of the first resist composition in the cleaning solution removed from the manufacturing apparatus is less than 200 ppb. Once the concentration of the components of the first resist composition in the cleaning solution is less than 200 ppb, the manufacturing step for producing the second resist composition can be initiated.

[0076] The concentration of the resist composition components contained in the cleaning solution detected by analysis is preferably less than 200 ppb, more preferably less than 100 ppb, even more preferably less than 60 ppb, and most preferably substantially absent (below the detection limit of the corona detector).

[0077] In the manufacturing method according to the embodiment of the present invention, the components of the first resist composition contained in the cleaning solution are components different from the organic solvent contained in the cleaning solution, and refer to each component constituting the first resist composition manufactured before cleaning, and the reaction products of each component. Specifically, the components of the first resist composition contained in the cleaning solution 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.

[0078] In embodiments of the present invention, the analytical method is not particularly limited and should be one that detects that the component concentration of the first resist composition contained in the washing solution is less than 200 ppb without performing a concentration step.

[0079] In the embodiments of the present invention, since high-sensitivity detection is possible without a concentration step, it is preferable to perform the analysis of the component concentrations of the resist composition in the analysis step using a method that utilizes liquid chromatography. In other words, it is preferable to analyze the washing solution using liquid chromatography in the analysis step. As the liquid chromatography, the same type as that described in the <Analysis Step> section of the [Analysis Method] above can be used.

[0080] From the viewpoint of enabling simple and highly accurate detection, it is preferable to perform the analysis using liquid chromatography equipped with a corona detector. As the corona detector, the same type as that described in the <Analysis Steps> section of the [Analysis Method] above can be used.

[0081] <Second manufacturing process> 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.

[0082] The second resist composition produced in this process is not particularly limited as long as it can form a resist film. For example, a resist composition containing a polymer and an organic solvent can be used, and is similar to the one described in (resist composition) in the [analytical method] above. 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.

[0083] <Other processes> The method for producing a resist composition according to an embodiment of the present invention may include other steps, within the scope of achieving the effects of the present invention. Other steps are not particularly limited, but examples include a step in the cleaning step to remove cleaning solution remaining inside or on the 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.

[0084] [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.

[0085] The defect suppression performance of the resist composition obtained by the method for manufacturing the resist composition according to the 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 in the resist film per silicon wafer is preferably less than 150, and more preferably less than 100. The above criteria can be appropriately selected depending on the application of the resist composition, i.e., the pattern shape, line width, layout, etc. The resist film can be formed by known methods.

[0086] In the production of the resist composition of the above-described embodiment, it is preferable that the various materials used (e.g., resist solvent, developer, rinse solution, anti-reflective film forming composition, top coat forming composition, etc.) do not contain 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 absent (below the detection limit of the measuring device).

[0087] 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)".

[0088] While fewer defects are desirable for optimal performance, it is practically difficult to eliminate extremely small defects entirely. Therefore, it is preferable that the number of defects with a size of 50 nm or larger 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.

[0089] As described above, according to the method for producing a resist composition according to the embodiment of the present invention, impurities in the resist composition can be reduced, and a resist composition excellent in suppressing the occurrence of defects in the resist film can be produced. [Examples]

[0090] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0091] <Synthesis of polymer compounds> Polymer compounds (A)-1 and (A)-2 were synthesized by radical polymerization using monomers that derive the constituent units of polymer compounds (A)-1 and (A)-2, respectively, in predetermined molar ratios. For the obtained polymer compounds (A)-1 and (A)-2, the carbon-13 nuclear magnetic resonance spectra were examined. 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.

[0092] [ka]

[0093] [Example 1] <Preparation of the first resist composition> Resist composition PR-1 was prepared (manufactured) 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. Each component shown in Table 1 was mixed and dissolved in the preparation tank, sensitivity and viscosity were adjusted by a predetermined method, and then the mixture was circulated within the apparatus and filtered by the filter.

[0094] [Table 1]

[0095] In Table 1, each abbreviation has the following meaning. The numbers in brackets [] in Table 1 indicate the amount (parts by mass) of each component.

[0096] (A)-1 and (A)-2: Base components consisting of polymer compounds represented by the above chemical formulas (A)-1 and (A)-2. (B)-1 and (B)-2: Acid generator components consisting of compounds represented by the following chemical formulas (B)-1 and (B)-2. (D)-1: Acid diffusion control agent component consisting of the compound represented by the following chemical formula (D)-1. (D)-2: Tri-n-octylamine (E)-1: Salicylic acid (S)-1: Mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) / propylene glycol monomethyl ether (PGME) = 20 / 80 by mass ratio. (S)-2: Mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) / propylene glycol monomethyl ether (PGME) = 60 / 40 by mass ratio.

[0097] [ka]

[0098] [ka]

[0099] <Cleaning of resist composition manufacturing equipment and analysis of cleaning solution> (Washing process) After removing the filtration filter from the manufacturing apparatus, all disassemblable components, specifically the supply piping, pump, filter, circulation piping, and valves, were disassembled and pre-cleaned. The manufacturing apparatus was then reassembled and the resist composition manufacturing apparatus was cleaned. The inside of the manufacturing apparatus was cleaned by circulating cleaning with a cleaning solution. For cleaning, acetone was used for pre-cleaning of disassemblable components, and propylene glycol monomethyl ether acetate (PGMEA) was used for circulating cleaning after reassembling the manufacturing equipment. For cleaning the disassemblable parts, a shower wash was performed using a wash bottle filled with acetone until no organic components could be visually confirmed to be attached. For circulating cleaning of the manufacturing equipment after the filtration filter was removed, an amount of acetone equivalent to approximately 10% of the tank capacity was added, and the inside was circulated for 15 minutes to clean it.

[0100] The above cleaning process involved repeating the circulation cleaning three times (number of cleaning cycles). After the third circulation cleaning was completed, 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 analysis method described below.

[0101] (Analysis process) The amount of organic components in the washing solution after washing was analyzed using a Thermo Fisher Scientific "Vanquish" liquid chromatography system. The analysis software used was Thermo Fisher Scientific's "Chromeleon" TM 7.3.2 (Product Name) was used. The measurement conditions are as follows. Flow rate: 1mL / min Washing solution injection volume: 100 μL Mobile phase: A mixed solvent of ultrapure water and an organic solvent. Measurement time: 9 min Column used: ODS Column temperature: 40℃ Detector: Corona detector (Thermo Fisher Scientific "Charged Aerosol Detector H" (product name))

[0102] Furthermore, the washing solution injected into the liquid chromatography apparatus was used directly after the washing process described above, without any pretreatment by concentration. The results are shown in Table 2.

[0103] <Preparation of the second resist composition> After the cleanliness of the manufacturing apparatus was confirmed through the above cleaning and analysis processes, PR-1, the same resist composition produced in <Preparation of the first resist composition>, was prepared (manufactured) using the cleaned resist composition manufacturing apparatus.

[0104] <Resist film formation> Using Tokyo Electron's "CLEAN TRACK LITHIUS Pro Z (product name)," the resist composition prepared in <Preparation of the second resist composition> was applied to a 300 mm diameter silicon wafer (hereinafter referred to as "wafer") by rotation at 1500 rpm, and then the wafer was dried to form a resist film.

[0105] <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

[0106] [Examples 2 and 3] The same procedure as in Example 1 was followed, except that the number of washes was changed as shown in Table 2.

[0107] [Example 4] The same procedure as in Example 3 was followed, except that the resist compositions prepared in <Preparation of the first resist composition> and <Preparation of the second resist composition> were changed to PR-2.

[0108] [Example 5] The procedure was the same as in Example 3, except that the resist composition prepared in <Preparation of the second resist composition> was changed to PR-2. In other words, in Example 5, different resist compositions were prepared in <Preparation of the first resist composition> and <Preparation of the second resist composition>.

[0109] [Comparative Examples 1 and 2] 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.

[0110] [Table 2]

[0111] A correlation was observed between the component concentration of the resist composition in the cleaning solution and the number of defects in the resist film formed with the second-processed resist composition, confirming that the cleanliness of the manufacturing equipment affects the quality of the resist composition. By controlling the component concentration of the resist composition in the cleaning solution to less than 200 ppb, it became possible to suppress the number of defects in the resist film formed by the resist composition to less than 70.

[0112] It was found that by detecting that the component concentration of the resist composition in the cleaning solution was less than 200 ppb, and then manufacturing a second resist composition, it was possible to suppress the number of defects in the resist film formed by the resist composition to less than 70, thereby enabling the production of a high-quality resist composition. [Explanation of symbols]

[0113] 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 cleaning step in which the manufacturing equipment for producing the resist composition is cleaned using a cleaning solution, The process includes an analysis step of taking out the cleaning solution used in the cleaning step and analyzing it, The analysis is an analytical method that detects, using liquid chromatography equipped with a corona detector, that the component concentration of the resist composition contained in the washing solution in the analytical step is less than 200 ppb without performing a concentration step.

2. The analytical method according to claim 1, wherein the cleaning solution comprises 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.

3. A first manufacturing step of manufacturing a first resist composition using a manufacturing apparatus for manufacturing resist compositions, A cleaning step in which the manufacturing apparatus is cleaned using a cleaning solution, An analysis step in which the cleaning solution used in the cleaning step is taken out and analyzed, The process includes a second manufacturing step of manufacturing a second resist composition using the aforementioned manufacturing apparatus, Prior to the second manufacturing step, the washing step and the analysis step are each performed at least once until the analysis detects that the concentration of the components of the first resist composition contained in the washing solution in the analysis step is less than 200 ppb without performing a concentration step. The above analysis is a method for producing a resist composition using liquid chromatography equipped with a corona detector.

4. The method for producing a resist composition according to claim 3, wherein the cleaning solution comprises 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.

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