Method for producing non-chemically amplified resist composition and pattern forming method

Abstract

To provide a method for producing a non-chemically amplified resist composition whose quality is controlled to be constant, and a pattern forming method.SOLUTION: (i) mixing a carboxy group-containing polymer, a hypervalent iodine compound, and a solvent in a container to prepare a resist composition bulk material; collecting a part of the resist composition bulk material and forming a resist film on a test substrate using the collected resist composition bulk material; A step (ii) of evaluating film physical properties of the resist film, and a step (iii) of adding and mixing an additional material to the resist composition bulk material based on an evaluation result of the step (ii) in order to obtain target film physical properties.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a non-chemically amplified resist composition and a method for forming a pattern. [Background technology]

[0002] As the IoT market expands, there is a growing demand for higher integration, higher speeds, and lower power consumption in LSIs, leading to rapid progress in miniaturization of pattern rules. Logic devices, in particular, are driving this miniaturization. The most advanced miniaturization technology is ArF immersion lithography, with double patterning, triple patterning, and quadruple patterning being used to mass-produce 10nm-node devices. Furthermore, studies are underway to develop 7nm-node devices using next-generation extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem (Non-Patent Document 1). It has been suggested that in order to ensure resolution in fine patterns with dimensions of 45 nm and below, not only is it important to improve dissolution contrast, as has been proposed in the past, but also to control acid diffusion (Non-Patent Document 2). However, because chemically amplified resist compositions increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the PEB time result in significant decreases in sensitivity and contrast.

[0004] Adding an acid generator that generates bulky acid is effective in suppressing acid diffusion. Therefore, copolymerization of an onium salt acid generator with a polymerizable olefin into a polymer has been proposed. However, for resist film pattern formation with dimensions of 16 nm or smaller, it is believed that chemically amplified resist compositions cannot be used to form patterns due to acid diffusion, and the development of non-chemically amplified resist compositions is desired.

[0005] One material for non-chemically amplified resist compositions is polymethyl methacrylate (PMMA), a positive resist material whose main chain is cleaved by EUV irradiation, resulting in a decrease in molecular weight, which improves solubility in organic solvent developers.

[0006] Hydrogen silsesquioxane (HSQ) is a negative resist material that becomes insoluble in alkaline developers due to crosslinking caused by the condensation reaction of silanols generated by EUV irradiation. Chlorine-substituted calixarenes also function as negative resist materials. These negative resist materials have small molecular size before crosslinking and are free of blurring due to acid diffusion, resulting in low edge roughness and extremely high resolution, and are used as pattern transfer materials to indicate the resolution limit of exposure equipment. However, these materials have insufficient sensitivity, and further improvement is needed.

[0007] One of the challenges in developing materials for EUV lithography is the low photon count in EUV exposure. EUV energy is much higher than that of ArF excimer laser light, and the photon count in EUV exposure is one-fourteenth that of ArF exposure. Furthermore, the pattern dimensions formed with EUV exposure are less than half those of ArF exposure. This makes EUV exposure susceptible to variations in photon count. The variations in photon count in the extremely short wavelength radiation region are a physical phenomenon known as shot noise, and this effect cannot be eliminated. Therefore, so-called stochastics has attracted attention. While the effects of shot noise cannot be eliminated, methods for reducing this effect are being discussed. Shot noise not only increases dimensional uniformity (CDU) and line width roughness (LWR), but also causes hole blockage with a probability of one in several million. Blocked holes result in poor electrical conductivity, preventing transistor operation and adversely affecting overall device performance. When considering practical sensitivity, resist compositions containing PMMA or HSQ as the main component are significantly affected by stochastics and are unable to achieve the desired resolution performance.

[0008] In light of these circumstances, the introduction of elements that have high absorption of EUV light has attracted attention as a method for reducing the effects of shot noise on the resist side. Patent Document 1 proposes a non-chemically amplified resist composition that uses a tin compound. Because this composition contains tin, which has high absorption of EUV light, as its main component, it improves stochastics and achieves high sensitivity and high resolution.

[0009] When preparing a non-chemically amplified resist composition, the resist composition materials, including the above-mentioned main materials, are dissolved in a solvent to form a coating solution, which is then microfiltered, if necessary, to remove particles, resulting in a completed resist composition. In preparing the resist composition, materials with certified purity are used, and precisely weighed masses are added. However, due to slight differences in the purity of the materials used or differences in the manufacturing atmosphere, the quality of the prepared non-chemically amplified resist composition may vary slightly depending on the product lot. However, requiring quality testing every time a resist composition is used before use is undesirable for the product; therefore, it is desirable for the quality of the resist composition to be consistently controlled once it is completed as a product.

[0010] In the case of chemically amplified resists, the resist composition is composed of multiple functional components, such as a resin whose solubility changes under the action of acid, an acid generator, and a quencher, and therefore quality can be adjusted and maintained at a constant level by adjusting the mixing ratio of each functional component, as proposed in Patent Document 2. On the other hand, non-chemically amplified resist compositions, such as those described in Patent Document 1, typically consist of only a single functional component and a solvent, and therefore have the problem of not being able to adjust quality in this way. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 2021-503482 [Patent Document 2] International Publication No. 2021 / 172172 [Non-patent literature]

[0012] [Non-Patent Document 1] SPIE Vol.5039 p1(2003) [Non-patent document 2] SPIE Vol.6520 p65203L-1(2007) Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a non-chemically amplified resist composition whose quality is controlled to a consistent level, and a method for forming a pattern. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides a method for producing a non-chemically amplified resist composition, comprising the steps of: (i) preparing a resist composition bulk by mixing a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent in a container; a step (ii) of collecting a portion of the resist composition bulk material, forming a resist film on a test substrate using the collected resist composition bulk material, and evaluating the film properties of the resist film; (iii) a step of adding and mixing additional materials to the resist composition base material to achieve the desired film properties based on the evaluation results of the step (ii); and a method for producing a non-chemically amplified resist composition comprising the above in this order.

[0015] This method for producing a non-chemically amplified resist composition makes it possible to produce a non-chemically amplified resist composition whose quality is controlled to a consistent level.

[0016] In the present invention, it is preferable that the film property is the sensitivity.

[0017] In the present invention, such film properties can be used as evaluation items.

[0018] In the present invention, it is preferable to use at least one of the carboxy group-containing polymer, the hypervalent iodine compound, and the solvent as the additional material.

[0019] Such additional materials are preferable because it is easier to maintain a consistent quality of the non-chemically amplified resist composition.

[0020] In the present invention, it is preferable to use, as the hypervalent iodine compound, one containing at least one of the compounds represented by the following general formulas (1) and (2). [ka] (In the formula, m and m1 are integers of 0 to 2. When m is 0, n is an integer of 0 to 4, when m is 1, n is an integer of 0 to 6, and when m is 2, n is an integer of 0 to 8. When m1 is 0, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 5, and 1≦(n1+n2)≦6 is satisfied. When m1 is 1, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 7, satisfying 1≦(n1+n2)≦8. When m1 is 2, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 9, and 1≦(n1+n2)≦10 is satisfied. R 1 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R 2 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n is 2 to 8, each R 2 may be the same or different. 2 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. R 3is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a hetero atom. *1 and *2 represent bonds to carbon atoms of an aromatic ring in the formula, provided that *1 and *2 must be bonded to adjacent carbon atoms of the aromatic ring. R 11 and R 12 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 11 and R 12 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 13 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 to 9, each R 13 may be the same or different. 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.)

[0021] In the present invention, it is preferable to use such a hypervalent iodine compound.

[0022] In the present invention, it is preferable to use, as the carboxy group-containing polymer, one containing a repeating unit represented by the following general formula (3). [ka] (In the formula, R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -X A1 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom of the main chain.

[0023] In the present invention, it is preferable to use such a carboxy group-containing polymer.

[0024] Further, the present invention provides a pattern forming method, comprising the steps of: forming a resist film on a substrate, or on an underlayer film of a substrate having an underlayer film laminated thereon, using the resist composition produced by the production method described above; exposing the resist film to high-energy radiation; developing the exposed resist film using a developer; The present invention provides a pattern formation method comprising the steps of:

[0025] The non-chemically amplified resist composition produced by the production method of the present invention can be used in such pattern formation methods. [Effects of the Invention]

[0026] The manufacturing method of the present invention is extremely useful for manufacturing a non-chemically amplified resist composition with consistently controlled quality. Furthermore, the non-chemically amplified resist composition obtained by the manufacturing method of the present invention can be used in pattern formation methods in, for example, the manufacturing process of semiconductor devices. DETAILED DESCRIPTION OF THE INVENTION

[0027] As described above, there has been a demand for the development of a method for producing a non-chemically amplified resist composition and a pattern formation method in which the quality is controlled to a consistent level.

[0028] As a result of extensive research into achieving the above-mentioned object, the present inventors discovered that the quality of a non-chemically amplified resist composition containing a hypervalent iodine compound, a carboxyl group-containing polymer, and a solvent as its main components can be controlled to a consistent level by adjusting the ratio of each component, thereby achieving the present invention.

[0029] That is, the present invention provides a method for producing a non-chemically amplified resist composition, comprising: (i) preparing a resist composition bulk by mixing a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent in a container; a step (ii) of collecting a portion of the resist composition bulk material, forming a resist film on a test substrate using the collected resist composition bulk material, and evaluating the film properties of the resist film; (iii) a step of adding and mixing additional materials to the resist composition base material to achieve the desired film properties based on the evaluation results of the step (ii); and a method for producing a non-chemically amplified resist composition comprising the steps of:

[0030] The present invention will be described in detail below, but the present invention is not limited thereto.

[0031] [Method of manufacturing a non-chemically amplified resist composition] The method for producing a non-chemically amplified resist composition of the present invention includes, in this order: step (i) of mixing a carboxy group-containing polymer, a hypervalent iodine compound, and a solvent in a container to prepare a resist composition bulk; step (ii) of, after step (i), sampling a portion of the resist composition bulk, forming a resist film on a test substrate using the sampled resist composition bulk, and evaluating the film properties of the resist film; and step (iii) of adding and mixing an additional material to the resist composition bulk to achieve desired film properties based on the evaluation results of step (ii).

[0032] Each step will be described in detail below.

[0033] [Step (i)] Step (i) is a step of preparing a resist composition bulk material by placing a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent in a container and mixing them. The container used in step (i) is not particularly limited, and for example, a known container used in the production of resist compositions can be used. The container is sufficient as long as it can accommodate the above-mentioned components and may or may not have a lid. The container may be sealed or unsealed. The material of the container is not particularly limited. The size of the container is not particularly limited, and may be of a size used in a typical laboratory or a size suitable for industrial production. The container may be one that allows operations such as heating, pressurization, and stirring of the components placed therein. For example, a reaction vessel, a kettle (e.g., a reaction vessel), a tank (e.g., a stirring tank), etc. can be used as the container. As the container, a stirring tank is preferably used for mixing the resist composition bulk material.

[0034] The manufacturing apparatus used in the manufacturing method of the present invention is not particularly limited as long as it has at least a container, and for example, known manufacturing apparatus used in manufacturing resist compositions can be used. For example, the apparatus may be equipped with a mechanism for introducing each component into the container (e.g., an inlet pipe, etc.), a mechanism for discharging the components from the container (e.g., an outlet pipe, etc.), a mechanism for reintroducing the components discharged from the container into the container (e.g., a circulation mechanism, etc.), a mechanism for removing impurities from the resist composition (e.g., a filter, etc.), a mechanism for stirring the resist composition (e.g., a stirring blade, etc.), a mechanism for cleaning the apparatus (e.g., a cleaning nozzle, etc.), etc. The material of the manufacturing apparatus is not particularly limited, but it is preferable that the liquid-contacting parts within the apparatus are lined or coated with a fluororesin or the like.

[0035] The method for adding each component to the container in step (i) is not particularly limited. For example, the components may be added through a material inlet of the container. When adding the components, the components may be added sequentially or all at once. When adding one component, the components may be added in multiple batches. When adding the components sequentially to the stirring tank, the order of addition is not particularly limited.

[0036] The atmosphere in the container in step (i) is not particularly limited. For example, the inside may be filled with air or other gases (such as nitrogen or argon). The inside of the container may be at normal pressure, pressurized, or reduced pressure.

[0037] The method for mixing the components in step (i) is not particularly limited, but mixing by stirring is preferred, and mixing by impellers is particularly preferred. When mixing by impellers, the size and material of the impellers are not particularly limited. The rotation speed of the impellers is not particularly limited, but is preferably 20 to 500 rpm, more preferably 40 to 350 rpm, and even more preferably 50 to 300 rpm. When mixing by stirring, the contents of the container may be stirred before the components are added, or stirring may be started after at least one component is added.

[0038] The mixing time in step (i) is not particularly limited, but is preferably 30 minutes or more, more preferably 1 hour or more, even more preferably 2 hours or more, still more preferably 4 hours or more, and particularly preferably 8 hours or more. The upper limit of the mixing time is not particularly limited, but from the viewpoint of productivity, it is preferably 24 hours or less, more preferably 18 hours or less, and even more preferably 12 hours or less.

[0039] The temperature during mixing (the temperature of the contents in the container) is not particularly limited, but is preferably 15 to 35°C, more preferably 20 to 25°C. Furthermore, the temperature of the contents in the container is preferably kept constant during mixing, preferably within ±10°C of the set temperature, more preferably within ±5°C, and even more preferably within ±1°C. Before stopping mixing, it is preferable to confirm that each component has been dissolved or uniformly dispersed in the solvent. During mixing, ultrasonic waves may be applied to the contents in the container.

[0040] The hypervalent iodine compound, the carboxy group-containing polymer, and the solvent used in step (i) will be described in detail below.

[0041] [Hypervalent iodine compounds] The hypervalent iodine compound is a general term for iodine compounds having valence electrons that formally exceed the octet rule. The hypervalent iodine compound used in the present invention is not particularly limited, and examples thereof include a tricoordinate hypervalent iodine compound having an oxidation number of +3 and a pentacoordinate hypervalent iodine compound having an oxidation number of +5.

[0042] As the hypervalent iodine compound, it is preferable to use a three-coordinate hypervalent iodine compound containing at least one of the compounds represented by the following general formulas (1) and (2). [ka] (In the formula, m and m1 are integers of 0 to 2. When m is 0, n is an integer of 0 to 4, when m is 1, n is an integer of 0 to 6, and when m is 2, n is an integer of 0 to 8. When m1 is 0, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 5, and 1≦(n1+n2)≦6 is satisfied. When m1 is 1, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 7, satisfying 1≦(n1+n2)≦8. When m1 is 2, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 9, and 1≦(n1+n2)≦10 is satisfied. R 1 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R 2 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n is 2 to 8, each R 2 may be the same or different. 2 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. R 3 is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a hetero atom. *1 and *2 represent bonds to carbon atoms of an aromatic ring in the formula, provided that *1 and *2 must be bonded to adjacent carbon atoms of the aromatic ring. R 11 and R 12 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 11 and R 12 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 13 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 to 9, each R 13 may be the same or different. 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.)

[0043] In the above general formula (1), m is an integer of 0 to 2. When m is 0, n is an integer of 0 to 4, when m is 1, n is an integer of 0 to 6, and when m is 2, n is an integer of 0 to 8. n is preferably 0, 1, 2, 3, or 4, more preferably 0, 1, 2, or 3, even more preferably 0, 1, or 2, and most preferably 0 or 1.

[0044] In the above general formula (1), R 1is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group having 1 to 10 carbon atoms may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as a decanyl group or an adamantyl group; alkenyl groups having 2 to 10 carbon atoms, such as a vinyl group or an allyl group; aryl groups having 6 to 10 carbon atoms, such as a phenyl group or a naphthyl group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms, such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- groups in the hydrocarbyl groups may be substituted with groups containing heteroatoms, such as oxygen atoms, sulfur atoms, or nitrogen atoms, resulting in the hydrocarbyl groups containing hydroxy groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), etc. 1 As the group, a hydrocarbyl group having 1 to 4 carbon atoms or a fluorinated hydrocarbyl group having 1 to 4 carbon atoms is preferred, and a hydrocarbyl group having 1 to 4 carbon atoms is more preferred.

[0045] In the above general formula (1), R 2is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group having 1 to 40 carbon atoms may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a decanyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 40 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. In addition, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), or the like. When n is 2 to 8, each R 2 may be the same or different. 2 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.

[0046] In the above general formula (1), R 3is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom. The hydrocarbylene group having 1 to 10 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkylene groups having 1 to 10 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-2,3-diyl group, butane-1,4-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, and decane-1,10-diyl group; cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group, and tricyclo[5.2.1.0]diyl group. 2,6 ]Cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as a decanediyl group; alkenylene groups having 2 to 10 carbon atoms, such as a vinylene group or a propynylene group; arylene groups having 6 to 10 carbon atoms, such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group or a naphthylene group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbylene group containing a hydroxy group, a cyano group, a halogenated alkyl group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), or the like. 3 is preferably a carbonyl group, a hydrocarbylene group having 1 to 4 carbon atoms, or a fluorinated hydrocarbylene group having 1 to 4 carbon atoms.

[0047] In the general formula (1), *1 and *2 represent bonds to the carbon atoms of the aromatic ring in the formula. However, *1 and *2 are bonded to adjacent carbon atoms of the aromatic ring. The combinations of *1, *2, and m can have the following seven patterns: [ka] (where n, R 2 and R 3 is the same as above. The dashed line indicates R 1 -C(=O)-O- represents a bond.)

[0048] Specific examples of the hypervalent iodine compound represented by the above general formula (1) include, but are not limited to, the following: In the following formula, Me is a methyl group. [ka]

[0049] [ka]

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[0104] In the above general formula (2), m1 is an integer of 0 to 2. When m1 is 0, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 5, and 1≦(n1+n2)≦6 is satisfied. When m1 is 1, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 7, satisfying 1≦(n1+n2)≦8. When m1 is 2, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 9, and 1≦(n1+n2)≦10 is satisfied.

[0105] In the above general formula (2), R 11 and R 12are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 11 and R 12 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between the carbon atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group having 1 to 10 carbon atoms may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as decanyl and adamantyl; alkenyl groups such as vinyl and allyl; aryl groups having 6 to 10 carbon atoms such as phenyl and naphthyl; and groups obtained by combining these. In addition, some or all of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, resulting in the hydrocarbyl groups containing hydroxy groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), etc. 11 and R 12 is preferably a hydrocarbyl group having 1 to 4 carbon atoms.

[0106] In the above general formula (2), R 13is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group having 1 to 40 carbon atoms may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0 2,6 cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a ]decanyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 40 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, or a carboxylic anhydride (-C(=O)-OC(=O)-). When n2 is 2 to 9, each R 13 may be the same or different. 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.

[0107] Specific examples of the hypervalent iodine compound represented by the above general formula (2) include, but are not limited to, the following.

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] The hypervalent iodine compound used in step (i) of the production method of the present invention may be a hypervalent iodine compound represented by the general formula (1) alone, a hypervalent iodine compound represented by the general formula (2) alone, or a combination of a hypervalent iodine compound represented by the general formula (1) and a hypervalent iodine compound represented by the general formula (2). The hypervalent iodine compound represented by the general formula (1) and the hypervalent iodine compound represented by the general formula (2) may each be used alone or in combination of two or more different types.

[0113] [Carboxy group-containing polymer] The carboxyl group-containing polymer used in step (i) of the production method of the present invention preferably contains a carboxyl group-containing repeating unit, and the carboxyl group-containing repeating unit is particularly preferably one represented by the following general formula (3): [ka] (In the formula, R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -XA1 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom of the main chain.

[0114] In the above general formula (3), R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -X A1 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom in the main chain.

[0115] Specific examples of the carboxyl group-containing repeating unit include, but are not limited to, the following: A is the same as above. [ka]

[0116] [ka]

[0117] The carboxyl group-containing polymer may further contain a repeating unit other than the carboxyl group-containing repeating unit (hereinafter also referred to as "other repeating units"). The other repeating units are not particularly limited, but are preferably those that can improve the solubility in a solvent of a polymer that is poorly soluble in a solvent when composed solely of a repeating unit having a carboxyl group. Preferred examples of such repeating units include repeating units having a hydrocarbyl group having 1 to 20 carbon atoms and optionally containing at least one selected from the group consisting of a halogen atom, a hydroxyl group, a cyano group, a carbonyl group, a nitro group, a sulfonic acid group, an amino group, an isocyanate group, an amide bond, an imide bond, an ester bond, an ether bond, a sulfide bond, a carbonate bond, a lactone ring, and a sultone ring.

[0118] Specific examples of the other repeating units include, but are not limited to, those shown below. A is the same as above, and X B are each independently —CH— or —O—.

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124]

change

[0125]

change

[0126]

change

[0127]

change

[0128]

change

[0129]

change

[0130]

change

[0131]

change

[0132]

change

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139]

change

[0140]

change

[0141]

change

[0142]

change

[0143]

change

[0144]

change

[0145]

change

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] In the carboxyl group-containing polymer, the molar ratio of the carboxyl group-containing repeating units to the other repeating units is preferably 10:90 to 90:10, more preferably 15:85 to 85:15, and even more preferably 20:80 to 80:20.

[0150] The weight average molecular weight (Mw) of the carboxy group-containing polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0151] Furthermore, if the carboxyl group-containing polymer has a narrow molecular weight distribution (Mw / Mn), the amount of polymers with low or high molecular weights compared to Mw will be small, making it less likely that foreign matter will be found on the pattern after exposure and less likely that the pattern shape will be deteriorated. Therefore, since the effects of Mw and Mw / Mn tend to become greater as pattern rules become finer, in order to obtain a resist composition that is suitable for use with fine pattern dimensions, it is preferable that the carboxyl group-containing polymer have a narrow distribution of Mw / Mn of 1.0 to 2.0.

[0152] The carboxyl group-containing polymer can be synthesized, for example, by polymerizing a monomer that provides the repeating unit described above in an organic solvent with the addition of a radical polymerization initiator by heating.

[0153] Specific examples of organic solvents used in the polymerization reaction include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Specific examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of the polymerization initiator added is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0154] The polymerization initiator may be added to the monomer solution and then fed to the reaction vessel. Alternatively, an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. From the perspective of quality control, it is preferable to prepare the monomer solution and the initiator solution independently and then add them dropwise, since radicals generated from the initiator during the waiting time may accelerate the polymerization reaction and produce an ultra-high molecular weight polymer. The acid labile group may be used as is after being introduced into the monomer, or may be protected or partially protected after polymerization. To adjust the molecular weight, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used in combination. In this case, the amount of the chain transfer agent added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0155] The amount of each monomer in the monomer solution may be appropriately set so as to achieve the preferred content ratio of the repeating units described above.

[0156] In the resist composition produced by the resist composition producing method of the present invention, the hypervalent iodine compound and the carboxy group-containing polymer are preferably contained in such a molar ratio that the content of the hypervalent iodine compound relative to the carboxy group-containing repeating units in the polymer is 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30. The hypervalent iodine compound may be used alone, or two or more types may be used in combination. The carboxy group-containing polymer may be used alone, or two or more types with different composition ratios, Mw, and / or Mw / Mn may be used in combination.

[0157] [solvent] The resist composition produced by the resist composition producing method of the present invention contains a solvent. The solvent used in step (i) of the producing method of the present invention is not particularly limited as long as it can dissolve the hypervalent iodine compound, the carboxyl group-containing polymer, and other components described below and can form a film. Such a solvent is preferably an organic solvent, and specific examples thereof include ketones such as cyclohexanone, methyl-2-n-pentyl ketone, and methyl isoamyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, 4-methyl-2-pentanol, and methyl 2-hydroxyisobutyrate; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, and propylene glycol monoethyl ether. Examples of suitable solvents include ethers such as propylene glycol dimethyl ether and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono tert-butyl ether acetate; carboxylic acids such as formic acid, acetic acid, and propionic acid; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0158] In the resist composition produced by the resist composition producing method of the present invention, the content of the solvent is preferably an amount such that the solids concentration in the resist composition is 0.1 to 20 mass%, more preferably an amount such that the solids concentration in the resist composition is 0.1 to 15 mass%, and even more preferably an amount such that the solids concentration in the resist composition is 0.1 to 10 mass%. In this specification, the solids content is a general term for all components of the resist composition other than the solvent. The solvents may be used alone or in combination of two or more.

[0159] [Other ingredients] In the production method of the present invention, in addition to the carboxyl group-containing polymer, the hypervalent iodine compound, and the solvent, other components may be added to the container. Examples of the other components include a surfactant, a crosslinking agent, and a radical scavenger. The other components may be added to the container in step (i), or may be added in a step other than step (i).

[0160] [Surfactants] The surfactant is preferably a fluorine-based and / or silicone-based surfactant. Specific examples of such surfactants include the surfactants described in paragraph

[0276] of U.S. Patent Application Publication No. 2008 / 0248425. Furthermore, surfactants other than the fluorine-based and / or silicone-based surfactants described in paragraph

[0280] of U.S. Patent Application Publication No. 2008 / 0248425 can also be used.

[0161] When the resist composition produced by the method of producing a resist composition of the present invention contains the surfactant, the content thereof is preferably 0.0001 to 2 mass% of the total solid content. The surfactant may be used alone, or two or more types may be used in combination.

[0162] [Radical scavengers] Specific examples of the radical scavenger include hindered phenols, quinones, hindered amines, and thiol compounds. Specific examples of the hindered phenols include dibutylhydroxytoluene (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Specific examples of the quinones include 4-methoxyphenol (methoquinone) and hydroquinone. Specific examples of the hindered amines include 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethylpiperidine-N-oxy radical. Specific examples of the thiol compound include dodecanethiol and hexadecanethiol.

[0163] When the resist composition produced by the method for producing a resist composition of the present invention contains the radical scavenger, the content thereof is preferably 0.01 to 10 mass % of the total solid content. The radical scavenger may be used alone, or two or more types may be used in combination.

[0164] [Crosslinking agent] Specific examples of the crosslinking agent include compounds having a carbon-carbon unsaturated bond as a functional group, such as a vinyl group, a (meth)acrylate group, an allyl group, an alkynyl group, or an aromatic ring. Specifically, specific examples of the compound having a vinyl group include chain alkenes, branched alkenes, cyclic alkenes, and the like, which may have a substituent. Specific examples of the compound having a (meth)acrylate group include acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, and the like, which may have a substituent. Specific examples of the compound having an allyl group include allyl alcohol, allyl ether, allyl ester, allyl amide, allyl amine, and allyl group-containing isocyanurates, which may have a substituent. Specific examples of the compound having an alkynyl group include chain alkynes, branched alkynes, cyclic alkynes, alkynyl alcohols, alkynyl ethers, alkynyl esters, alkynyl amides, alkynyl amines, and alkynyl group-containing isocyanurates, each of which may have a substituent. Specific examples of compounds having an aromatic ring include arenes, heteroarenes, styrene, stilbene, phenylacetylene, acenaphthylene, chalcone, and the like, which may have a substituent.

[0165] The crosslinking agent may have only one or more of the functional groups. The number of functional groups contained in the crosslinking agent is preferably 1 or more and 10 or less, and more preferably 2 or more and 8 or less.

[0166] When the resist composition produced by the method for producing a resist composition of the present invention contains the crosslinking agent, the content thereof is preferably 0.01 to 50 mass % of the total solid content. The crosslinking agents may be used alone, or in combination of two or more.

[0167] [Step (ii)] In the method for producing a resist composition of the present invention, after step (i), a step (ii) is carried out in which a portion of the resist composition bulk material prepared in step (i) is sampled, the sampled resist composition bulk material is used to form a resist film on a test substrate, and the film properties of the resist film are evaluated.

[0168] The film properties evaluated in the above step (ii) are not particularly limited, but are preferably at least one of sensitivity, film thickness, contact angle (e.g., water contact angle), complex refractive index, transmittance, and refractive index, more preferably at least one of sensitivity and film thickness, and particularly preferably sensitivity.

[0169] The method for evaluating the film properties in the step (ii) is not particularly limited, and known methods for evaluating film properties can be used. When evaluating sensitivity as a film property, the type of high-energy radiation to be irradiated is not particularly limited. Examples include ultraviolet light, far ultraviolet light, EB, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. Among these, KrF excimer laser light, EB, and EUV are preferred, and EB or EUV is particularly preferred.

[0170] The test substrate used in the above step (ii) can be the same as the substrate used in the pattern forming method described below.

[0171] [Step (iii)] In the method for producing a resist composition of the present invention, after step (ii), step (iii) is carried out in which an additional material is added to and mixed with the resist composition bulk material to achieve the desired film properties based on the evaluation results of step (ii). The type of additional material is not particularly limited, but is preferably at least one of a carboxyl group-containing polymer, a hypervalent iodine compound, a solvent, a surfactant, a crosslinking agent, and a radical scavenger, more preferably at least one of a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent, and particularly preferably a hypervalent iodine compound.

[0172] In order to adjust the sensitivity, it is conceivable to add, for example, a hypervalent iodine compound. In order to adjust the film thickness, for example, a solvent may be added. In order to adjust the contact angle, it is conceivable to add, for example, a carboxyl group-containing polymer. In order to adjust the complex refractive index, for example, it is conceivable to add a hypervalent iodine compound. In order to adjust the transmittance, it is conceivable to add, for example, a hypervalent iodine compound. In order to adjust the refractive index, it is conceivable to add, for example, a carboxyl group-containing polymer.

[0173] In the resist composition manufacturing method of the present invention, step (i) is followed by step (ii), and then step (iii). In this case, each of steps (i) to (iii) may be performed consecutively with the previous step, or may be performed with a time lapse after the previous step. The addition of the additional material in step (iii) may be performed to the resist composition bulk contained in the container used in step (i), or may be performed to the resist composition bulk transferred to another container, etc. In step (iii), the resist composition bulk may or may not be stirred when the additional material is added, but stirring is preferred. In the manufacturing method of the present invention, the container may be continuously stirred from the start of step (i) to the end of step (iii). Furthermore, the container may also be stirred after the end of step (iii) (after the addition of the additional material has been completed).

[0174] The amount of the additional material added in step (iii) (the total amount when multiple materials are added) is preferably 0.001 to 100 mass%, more preferably 0.001 to 50 mass%, and even more preferably 0.001 to 30 mass% of the total amount of the hypervalent iodine compound, carboxy group-containing polymer, and solvent placed in the container in step (i).

[0175] If the film properties measured in step (ii) are already the desired film properties, then step (iii) may involve only stirring without adding any additional materials. In this case, step (iii) can be said to be a step of determining, based on the evaluation results of step (ii), whether or not to add any additional materials to the resist composition bulk material in order to achieve the desired film properties.

[0176] The reason why the present invention solves the above problems is not entirely clear, but the present inventors believe as follows.

[0177] When the hypervalent iodine compound used in the present invention is mixed with a carboxylic acid compound, an equilibrium reaction occurs in which the ligand on the iodine is exchanged with the carboxylic acid compound. If the original ligand can be removed in some way, a hypervalent iodine compound with a new ligand is generated. For example, 1-acetoxy-1,2-benziodoxol-3-(1H)-one, a relatively readily available hypervalent iodine compound, is mixed with a high-molecular-weight carboxylic acid compound, and the resulting low-boiling acetic acid is removed to complete the ligand exchange. If the carboxylic acid compound is a carboxyl-containing polymer, the carboxyl-containing polymer and the hypervalent iodine compound are combined to form a high-molecular-weight hypervalent iodine compound.

[0178] High molecular weight hypervalent iodine compounds are generated during film formation. This is because even if such high molecular weight hypervalent iodine compounds are synthesized in advance, they are insoluble in many organic solvents, making it impossible to prepare a solution. This is presumably because hypervalent iodine compounds, which have low solvent solubility due to their inherent high polarization, become even less soluble when a high molecular weight carboxyl group-containing polymer is used as a ligand. Therefore, it is desirable to remove the original low molecular weight carboxylic acid component during film formation and the subsequent baking process to complete the ligand exchange reaction and form a resist film.

[0179] The resist film thus formed on the substrate undergoes photodecomposition of its main component, the hypervalent iodine compound, which changes polarity, and a pattern is formed by the development process. By selecting an appropriate developer, either a positive or negative pattern can be formed.

[0180] Based on the above speculation, it can be said that the resist composition produced by the present invention is a non-chemically amplified resist composition. Furthermore, as mentioned above, the resist film is formed by reacting the hypervalent iodine compound and the carboxyl group-containing polymer in the resist composition during film formation, and therefore the film properties (e.g., sensitivity, film thickness, contact angle, complex refractive index, transmittance, refractive index) vary depending on the mixing ratio of the hypervalent iodine compound and the carboxyl group-containing polymer in the resist composition. In other words, by adjusting the ratio of each component in the resist composition using the resist production method of the present invention, it is possible to produce a non-chemically amplified resist composition with consistently controlled quality.

[0181] As a non-chemically amplified resist composition capable of forming fine patterns, a metal resist whose main component is a metal tin compound, which has a high absorption capacity for EUV light similar to that of iodine atoms, has been reported (e.g., Patent Document 1). However, as mentioned above, such metal resists typically consist of only a single functional component and a solvent, which poses the problem of making it impossible to adjust the quality. On the other hand, with the method for producing a non-chemically amplified resist composition of the present invention, the produced non-chemically amplified resist composition is composed of multiple components, and by adjusting the ratio of each component, it is possible to produce a non-chemically amplified resist composition with consistently controlled quality. From these points of view, it can be said that the method for producing a non-chemically amplified resist of the present invention is advantageous over conventional methods for producing non-chemically amplified resists.

[0182] JP 2023-167368 A proposes a non-chemically amplified resist composition using a hypervalent iodine compound, but does not mention the possibility of adjusting the film properties by adjusting the ratio of each component in the non-chemically amplified resist composition, or any specific method for producing the non-chemically amplified resist composition. Therefore, it is believed that this patent document does not suggest a method for producing a non-chemically amplified resist composition with consistently controlled quality, as in the present invention. In other words, it can be said that the present invention clearly provides a novel method for producing a non-chemically amplified resist composition.

[0183] [Pattern formation method] The non-chemically amplified resist composition produced by the above-described production method of the present invention can be used, for example, for pattern formation in the process of manufacturing semiconductor devices, etc. When the non-chemically amplified resist composition produced by the production method of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied.

[0184] That is, the present invention provides a pattern formation method, which includes the steps of: forming a resist film on a substrate, or on an underlayer film of a substrate having an underlayer film laminated thereon, using a resist composition produced by the production method described above; exposing the resist film to high-energy radiation; developing the exposed resist film using a developer; The present invention provides a pattern formation method comprising the steps of:

[0185] Each step of the pattern forming method of the present invention will be described in detail below.

[0186] First, the resist composition produced by the production method of the present invention is applied to a substrate for integrated circuit production, or to an underlayer film of a substrate laminated with an underlayer film (e.g., Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating), or to a substrate for mask circuit production, or to an underlayer film of a substrate laminated with an underlayer film (e.g., CrO, CrON, MoSi2, SiO2), by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating. The coating is preferably applied to a thickness of 0.01 to 2 μm. This is then prebaked on a hot plate, preferably at 60 to 200°C for 10 seconds to 30 minutes, more preferably at 80 to 180°C for 30 seconds to 20 minutes, to form a resist film. The underlayer film refers to a film formed between the substrate and the resist film in a multilayer resist process. The underlayer film is not particularly limited, and conventionally known underlayer films can be used. It is also preferable to filter the resist composition as needed before application. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

[0187] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, electron beam (EB), extreme ultraviolet radiation (EUV), X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 300 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 200 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 2000 μC / cm 2 either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 0.5 to 1500 μC / cm 2The resist composition produced by the production method of the present invention is particularly suitable for fine patterning using high-energy rays such as EB or EUV.

[0188] After exposure, PEB is performed as needed, preferably on a hot plate or in an oven at 30 to 150°C for 10 seconds to 30 minutes, more preferably at 60 to 120°C for 30 seconds to 20 minutes.

[0189] After exposure or PEB, the film is developed with a developer to form a pattern. Examples of the developer include an alkaline aqueous solution such as a tetramethylammonium hydroxide solution; 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, isopropyl alcohol, isoamyl alcohol, n-butanol, n-pentanol, cyclohexanol, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, and propionic acid. Examples of organic solvents that can be used include methyl, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, 2-propanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, and 4-methyl-2-pentanol. These developers may be used alone or in combination of two or more.

[0190] After development, rinsing is performed as necessary. A preferred rinsing solution is a solvent that is miscible with the developer but does not dissolve the resist film. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0191] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0192] Furthermore, the pattern formed by the above-described pattern formation method may be used as a mask to perform an etching process on the substrate. That is, the pattern formed by the above-described pattern formation method may be used as a mask to process the substrate (or the underlying film and the substrate) to form a pattern on the substrate.

[0193] The method for processing the substrate (or the underlayer film and the substrate) is not particularly limited, but a method of forming a pattern on the substrate by dry etching the substrate (or the underlayer film and the substrate) using the pattern formed in the above-mentioned process as a mask is preferred.

[0194] The dry etching may be a single-stage etching or a multi-stage etching. When the etching is a multi-stage etching, the etching in each stage may be the same process or different processes.

[0195] Any known etching method can be used, and various conditions, etc., are determined appropriately depending on the type or application of the substrate, etc. For example, etching can be performed in accordance with the methods described in Proc. of SPIE Vol. 6924, 692420 (2008) and JP 2009-267112 A. Alternatively, etching can be performed in accordance with the method described in "Chapter 4: Etching" in "Semiconductor Processing Textbook, Fourth Edition, Published in 2007, Publisher: SEMI Japan."

[0196] The resist composition produced by the production method of the present invention and the various materials used in the present invention (e.g., carboxyl group-containing polymer, hypervalent iodine compound, solvent, surfactant, crosslinking agent, radical scavenger, developer, and rinse) preferably do not contain impurities such as metals. The content of impurities contained in these materials is preferably 1 ppm by mass or less, more preferably 10 ppb by mass or less, even more preferably 100 ppt by mass or less, particularly preferably 10 ppt by mass or less, and most preferably 1 ppt by mass or less. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Mo, Zr, Pb, Ti, V, W, and Zn.

[0197] Methods for removing impurities such as metals from resist compositions and various materials include, for example, filtration using a filter. The filter pore size is preferably 0.20 μm or less, more preferably 0.05 μm or less, and even more preferably 0.01 μm or less.

[0198] Preferred filter materials include fluororesins such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA), polyolefin resins such as polypropylene and polyethylene, polyamide resins such as nylon 6 and nylon 66, and polyimide resins. The filters used may be pre-washed with an organic solvent. In the filter filtration process, multiple or different types of filters may be connected in series or parallel. When multiple types of filters are used, filters with different pore sizes and / or materials may be combined. Various materials may be filtered multiple times, and the process of filtering multiple times may be a circulating filtration process.

[0199] In addition to filtration, impurities may be removed using an adsorbent, or a combination of filtration and an adsorbent may be used. Known adsorbents can be used as the adsorbent, such as inorganic adsorbents such as silica gel or zeolite, or organic adsorbents such as activated carbon. Examples of metal adsorbents include those disclosed in JP 2016-206500 A.

[0200] Furthermore, methods for reducing impurities such as metals contained in the resist composition and various materials include selecting raw materials with low metal contents as raw materials for the resist composition and various materials, filtering the raw materials for the resist composition and various materials, or performing distillation under conditions that minimize contamination by lining or coating the inside of an apparatus with a fluororesin, etc. Preferred conditions for filtering the raw materials for the resist composition and various materials are the same as those described above.

[0201] The various materials may be diluted with the solvent used in the resist composition before use. [Example]

[0202] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0203] [1] Resist composition Table 1 shows the compositions of the resist compositions (resists 1 and 2) used in the examples.

[0204] [Table 1]

[0205] Here, the "standard lot" refers to the lot manufactured 11 months prior to the new lot being mixed, and the "previous lot" refers to the lot manufactured 2 months prior to the new lot being mixed.

[0206] [2] Hypervalent iodine compounds The structures of the hypervalent iodine compounds (I-1 to I-2) used in the examples are shown below. [ka]

[0207] [3] Carboxy group-containing polymer The structures of the carboxyl group-containing polymers (P-1 to P-2) used in the examples are shown below. [ka]

[0208] [4] Solvent The solvents used in the examples and comparative examples are shown below. HBM: methyl 2-hydroxyisobutyrate PGMEA: Propylene glycol monomethyl ether acetate PA: Propionic acid AA: acetic acid

[0209] [5] Other ingredients The structure of the radical scavenger T-1 used in the examples is shown below. [ka]

[0210] [6] Method for producing resist composition [Example] Step (i): The carboxyl group-containing polymer, hypervalent iodine compound, solvent, and other components were placed in a stirring tank (volume 100 L) in the amounts shown in Table 1, and the contents in the stirring tank were stirred using a stirring blade at 23°C and 150 rpm for 2 hours to obtain a resist composition base material.

[0211] Step (ii): After step (i), 0.1 kg of the resist composition bulk was taken and designated as a "new lot." This "new lot" was used to evaluate the physical properties shown below.

[0212] -Evaluation of film properties- The 0.1 kg fraction and two reference resist compositions (standard lot and previous lot) were spin-coated onto Si substrates and pre-baked (PAB) at 130°C for 60 seconds using a hot plate to produce resist films with a thickness of 40 nm. The sensitivity and film thickness of the resulting resist films were evaluated as follows.

[0213] ·sensitivity The wafer on which the resist film was formed was exposed to a 20 nm line width, 1:1 line and space pattern using an electron beam exposure system (Elionix, ELS-F125, accelerating voltage 125 keV), and then baked at 90°C for 60 seconds (PEB). The wafer was then developed with butyl acetate as a developer for 30 seconds and spin-dried. The LS pattern for sensitivity evaluation thus obtained was observed using a Hitachi High-Technologies Corporation critical dimension SEM (CG-4000) to determine the optimal exposure dose Eop (μC / cm) for obtaining an LS pattern with a space width of 20 nm and a pitch of 40 nm. 2 ) was calculated and used as the sensitivity.

[0214] Film thickness The resist film was measured at multiple points using a film thickness meter (VM-3210; manufactured by SCREEN), and the average value was taken as the film thickness.

[0215] The results obtained are shown in Table 2.

[0216] [Table 2]

[0217] As a result, it was confirmed that <Resist 1 / New Lot> had a coating thickness 5nm thinner than <Resist 1 / Standard Lot> and <Resist 1 / Previous Lot> at the same rotation speed, and that its sensitivity was more than 2% higher. It was also confirmed that <Resist 2 / New Lot> had a coating thickness 5nm thicker than <Resist 2 / Standard Lot> and <Resist 2 / Previous Lot> at the same rotation speed, and that its sensitivity was more than 1% lower.

[0218] Step (iii): To the resist composition bulk material in the stirring tank, the additional materials shown in Table 3 were added. From the start of step (i) to the end of step (iii), the inside of the vessel was continuously stirred with a stirring blade. After the end of step (iii) (after all the additional materials had been added), the resist composition bulk material was continuously stirred for 4 hours.

[0219] [Table 3]

[0220] 0.1 kg of the resist composition bulk finely adjusted in this manner was taken out, and new lot resists 1 and 2 were again evaluated by the above-described methods. The results are shown in Table 4.

[0221] [Table 4]

[0222] As a result, the finely adjusted new lot resists 1 and 2 were almost equivalent in both film thickness and sensitivity to the <standard lot> and <previous lot>.

[0223] Table 5 shows the composition of the resist composition used in the comparative example (Comparative Example 1).

[0224] [Table 5]

[0225] In Table 5, R-1 (tin compound) used in Comparative Example 1 was synthesized according to Angewandte Chemie, International Edition (2017), 56 (34), 10140-10144. The structure of R-1 is as follows. [ka]

[0226] [Comparative Example] Step (i): The resist raw materials and solvent were placed in a stirring tank (volume 100 L) in the amounts shown in Table 5, and the contents in the stirring tank were stirred using a stirring blade at 23°C and 150 rpm for 2 hours to obtain a resist composition.

[0227] Step (ii): After step (i), 0.1 kg of the resist composition was taken out and designated as a "new lot." Using this "new lot," the physical properties were evaluated in the same manner as in the examples.

[0228] The results obtained are shown in Table 6.

[0229] [Table 6]

[0230] As a result, the non-chemically amplified resist compositions prepared in the comparative examples had significantly different film thicknesses and sensitivities among the <new lot>, <standard lot>, and <previous lot>.

[0231] From the above results, it was found that by using the manufacturing method of the present invention, a non-chemically amplified resist composition with consistently controlled quality can be obtained.

[0232] The present specification includes the following aspects. [1]: A method for producing a non-chemically amplified resist composition, (i) preparing a resist composition bulk by mixing a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent in a container; a step (ii) of collecting a portion of the resist composition bulk material, forming a resist film on a test substrate using the collected resist composition bulk material, and evaluating the film properties of the resist film; (iii) a step of adding and mixing additional materials to the resist composition base material to achieve the desired film properties based on the evaluation results of the step (ii); 1. A method for producing a non-chemically amplified resist composition, comprising the steps of: [2]: The method for producing a non-chemically amplified resist composition according to the above [1], wherein the film physical property is sensitivity. [3]: The method for producing a non-chemically amplified resist composition according to [1] or [2] above, wherein the additional material is at least one of the carboxyl group-containing polymer, the hypervalent iodine compound, and the solvent. [4]: A method for producing a non-chemically amplified resist composition according to any one of [1] to [3] above, characterized in that the hypervalent iodine compound contains at least one of compounds represented by the following general formulas (1) and (2): [ka] (In the formula, m and m1 are integers of 0 to 2. When m is 0, n is an integer of 0 to 4, when m is 1, n is an integer of 0 to 6, and when m is 2, n is an integer of 0 to 8. When m1 is 0, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 5, and 1≦(n1+n2)≦6 is satisfied. When m1 is 1, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 7, satisfying 1≦(n1+n2)≦8. When m1 is 2, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 9, and 1≦(n1+n2)≦10 is satisfied. R 1 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R 2 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n is 2 to 8, each R 2may be the same or different. 2 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. R 3 is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a hetero atom. *1 and *2 represent bonds to carbon atoms of an aromatic ring in the formula, provided that *1 and *2 must be bonded to adjacent carbon atoms of the aromatic ring. R 11 and R 12 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 11 and R 12 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 13 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 to 9, each R 13 may be the same or different. 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.) [5]: The method for producing a non-chemically amplified resist composition according to any one of [1] to [4] above, wherein the carboxyl group-containing polymer contains a repeating unit represented by the following general formula (3): [ka] (In the formula, R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -X A1is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom of the main chain. [6]: A pattern forming method, forming a resist film on a substrate, or on an underlayer film of a substrate having an underlayer film laminated thereon, using a resist composition produced by any one of the production methods [1] to [5] above; exposing the resist film to high-energy radiation; developing the exposed resist film using a developer; A pattern forming method comprising the steps of:

[0233] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. A method for producing a non-chemically amplified resist composition, comprising: (i) preparing a resist composition bulk by mixing a carboxyl group-containing polymer, a hypervalent iodine compound, and a solvent in a container; a step (ii) of collecting a portion of the resist composition bulk material, forming a resist film on a test substrate using the collected resist composition bulk material, and evaluating the film properties of the resist film; (iii) adding and mixing additional materials to the resist composition precursor to achieve the desired film properties based on the evaluation results of the step (ii); 1. A method for producing a non-chemically amplified resist composition, comprising the steps of:

2. 2. The method for producing a non-chemically amplified resist composition according to claim 1, wherein the film physical property is sensitivity.

3. 2. The method for producing a non-chemically amplified resist composition according to claim 1, wherein the additional material is at least one of the carboxyl group-containing polymer, the hypervalent iodine compound, and the solvent.

4. 4. The method for producing a non-chemically amplified resist composition according to claim 1, wherein the hypervalent iodine compound contains at least one of compounds represented by the following general formulas (1) and (2): 【Chemistry 1】 (In the formula, m and m1 are integers of 0 to 2. n is an integer of 0 to 4 when m is 0, an integer of 0 to 6 when m is 1, and an integer of 0 to 8 when m is 2. When m1 is 0, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 5, and 1≦(n1+n2)≦6 is satisfied. When m1 is 1, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 7, and 1≦(n1+n2)≦8 is satisfied. When m1 is 2, n1 is an integer of 1 to 3, and n2 is an integer of 0 to 9, and 1≦(n1+n2)≦10 is satisfied. R １ is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R ２ is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n is 2 to 8, each R ２ may be the same or different. ２ may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. R ３ is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom. *1 and *2 represent bonds to carbon atoms of the aromatic ring in the formula, provided that *1 and *2 must be bonded to adjacent carbon atoms of the aromatic ring. R １１ and R １２ are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. １１ and R １２ may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R １３ is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 to 9, each R １３ may be the same or different. １３ may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded.)

5. 4. The method for producing a non-chemically amplified resist composition according to claim 1, wherein the carboxyl group-containing polymer contains a repeating unit represented by the following general formula (3): 【Chemistry 2】 (In the formula, R Ａ is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X Ａ represents a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-X Ａ１ - is. X Ａ１ is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom of the main chain.

6. A pattern formation method, comprising: forming a resist film on a substrate, or on an underlayer film of a substrate having an underlayer film laminated thereon, using a resist composition produced by the production method according to any one of claims 1 to 3; exposing the resist film to high-energy radiation; developing the exposed resist film using a developer; A pattern forming method comprising the steps of:

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