Method for producing semiconductor substrate and resist underlayer film forming composition

Abstract

The purpose of the present invention is to provide: a method for producing a semiconductor substrate, the method using a resist underlayer film forming composition which is capable of forming a resist underlayer film that has excellent solvent resistance and excellent pattern rectangularity; and a resist underlayer film forming composition. The present invention provides a method for producing a semiconductor substrate, the method comprising: a step in which a resist underlayer film forming composition is directly or indirectly applied to a substrate; a step in which a resist film forming composition is applied to a resist underlayer film that is formed by the above-described resist underlayer film forming composition application step; a step in which a resist film that is formed by the above-described resist film forming composition application step is subjected to light exposure by means of radiation; and a step in which at least the light-exposed resist film is developed. With respect to this method for producing a semiconductor substrate, the resist underlayer film forming composition contains a solvent and a polymer that has a sulfonic acid ester structure.

Description

Semiconductor substrate manufacturing method and composition for forming resist underlayer film

[0001] The present invention relates to a method for producing a semiconductor substrate and a composition for forming a resist underlayer film.

[0002] In the manufacture of semiconductor devices, for example, a multilayer resist process is used in which a resist pattern is formed by exposing and developing a resist film laminated on a substrate via a resist underlayer film such as an organic underlayer film or a silicon-containing film. In this process, the resist underlayer film is etched using the resist pattern as a mask, and the substrate is further etched using the resulting resist underlayer film pattern as a mask, thereby forming a desired pattern on the semiconductor substrate.

[0003] In recent years, semiconductor devices have become increasingly highly integrated, and the wavelength of the exposure light used has tended to be shortened from KrF excimer lasers (248 nm) and ArF excimer lasers (193 nm) to extreme ultraviolet light (13.5 nm, hereinafter also referred to as "EUV"). Various studies have been conducted on compositions for forming resist underlayer films (see International Publication No. 2013 / 141015).

[0004] International Publication No. 2013 / 141015

[0005] The resist underlayer film is required to have solvent resistance to the solvent in the resist composition, and pattern rectangularity that prevents pattern footing at the bottom of the resist film and ensures rectangularity of the resist pattern.

[0006] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a method for producing a semiconductor substrate using a composition for forming a resist underlayer film, which is capable of forming a resist underlayer film that is excellent in solvent resistance and pattern rectangularity, and a composition for forming a resist underlayer film.

[0007] In one embodiment, the present invention relates to a method for producing a semiconductor substrate, comprising: a step of applying a composition for forming a resist underlayer film directly or indirectly to a substrate; a step of applying a composition for forming a resist film to the resist underlayer film formed in the step of applying the composition for forming a resist film; a step of exposing the resist film formed in the step of applying the composition for forming a resist film to radiation; and a step of developing at least the exposed resist film, wherein the composition for forming a resist underlayer film contains a polymer having a sulfonate ester structure (hereinafter also referred to as "polymer [A]") and a solvent (hereinafter also referred to as "solvent [C]").

[0008] In another embodiment, the present invention relates to a composition for forming a resist underlayer film, comprising: a polymer having a sulfonate ester structure; and a solvent.

[0009] According to the method for producing a semiconductor substrate, a composition for forming a resist underlayer film capable of forming a resist underlayer film having excellent solvent resistance and pattern rectangularity is used, thereby enabling efficient production of semiconductor substrates. The composition for forming a resist underlayer film can form a film having excellent solvent resistance and pattern rectangularity. Therefore, these compositions can be suitably used in the production of semiconductor devices, etc.

[0010] Hereinafter, the method for producing a semiconductor substrate and the composition for forming a resist underlayer film according to each embodiment of the present invention will be described in detail.

[0011] <<Method for Manufacturing Semiconductor Substrate>> The method for manufacturing a semiconductor substrate includes a step of applying a composition for forming a resist underlayer film directly or indirectly to a substrate (hereinafter also referred to as a “coating step (I)”), a step of applying a composition for forming a resist film to the resist underlayer film formed in the above-mentioned coating step of the composition for forming a resist film (hereinafter also referred to as a “coating step (II)”), a step of exposing the resist film formed in the above-mentioned coating step of the composition for forming a resist film to radiation (hereinafter also referred to as an “exposure step”), and a step of developing at least the exposed resist film (hereinafter also referred to as a “development step”).

[0012] According to the method for producing a semiconductor substrate, by using a predetermined composition for forming a resist underlayer film in the coating step (I), a resist underlayer film having excellent solvent resistance and pattern rectangularity can be formed, and therefore a semiconductor substrate having a good pattern shape can be produced.

[0013] It is preferable that the method for producing a semiconductor substrate further includes, before the coating step (II), a step of heating the resist underlayer film formed in the resist underlayer film-forming composition coating step at 200°C or higher (hereinafter also referred to as a "heating step").

[0014] The method for producing a semiconductor substrate may further include, as necessary, a step of forming a silicon-containing film directly or indirectly on the substrate (hereinafter also referred to as a "silicon-containing film-forming step") prior to the coating step (I).

[0015] Hereinafter, a description will be given of the composition for forming a resist underlayer film used in the method for producing a semiconductor substrate, as well as each step in the case where the method includes a heating step, which is a preferred step, and a silicon-containing film-forming step, which is an optional step.

[0016] <Composition for forming a resist underlayer film> The composition for forming a resist underlayer film (hereinafter also referred to as the "composition") contains a polymer [A] and a solvent [C]. The composition may contain optional components within a range that does not impair the effects of the present invention. By containing the polymer [A] and the solvent [C], the composition for forming a resist underlayer film can form a resist underlayer film that is excellent in solvent resistance and pattern rectangularity. Although the reason for this is unclear, it is presumed as follows. The composition for forming a resist underlayer film uses a polymer having a sulfonate ester structure in which sulfonic acid is protected (i.e., polymer [A]) as the main component, thereby reducing solubility in organic solvents. Furthermore, sulfonic acid generated by decomposition of the sulfonate ester in the resist underlayer film supplies acid to the bottom of the resist film in the exposed area during the exposure step, thereby increasing solubility in a developer at the bottom of the resist film and achieving pattern rectangularity.

[0017] <Polymer (A)> The polymer (A) has a sulfonate structure. The composition may contain one or more types of polymer (A).

[0018] The polymer [A] preferably has at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (1) (hereinafter also referred to as "repeating unit (1)") and a repeating unit represented by the following formula (2) (hereinafter also referred to as "repeating unit (2)"). When the polymer [A] has one or both of the repeating unit (1) and the repeating unit (2), a sulfonate ester structure can be suitably introduced into the polymer [A].

[0019]

[0020] In the above formulas (1) and (2), R １１ and R ２１ are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. １２ and R ２２ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. １ is a single bond or a divalent linking group. ２ is a divalent linking group.

[0021] In this specification, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" includes saturated hydrocarbon groups and unsaturated hydrocarbon groups. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not contain a ring structure and is composed only of a linear structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic structure as a ring structure and does not contain an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups (however, it does not have to be composed only of an alicyclic structure and may contain a linear structure as part of it). The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure (however, it does not have to be composed only of an aromatic ring structure and may contain an alicyclic structure or a linear structure as part of it).

[0022] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, and neopentyl; alkenyl groups such as ethenyl, propenyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0023] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; cycloalkenyl groups such as a cyclopropenyl group, a cyclopentenyl group and a cyclohexenyl group; bridged ring saturated hydrocarbon groups such as a norbornyl group, an adamantyl group and a tricyclodecyl group; and bridged ring unsaturated hydrocarbon groups such as a norbornenyl group and a tricyclodecenyl group.

[0024] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a naphthyl group, an anthracenyl group, and a pyrenyl group.

[0025] R １１ , R １２ , R ２１ and R ２２ When has a substituent, examples of the substituent include a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group, an alkoxycarbonyl group such as a methoxycarbonyl group or an ethoxycarbonyl group, an alkoxycarbonyloxy group such as a methoxycarbonyloxy group or an ethoxycarbonyloxy group, an acyl group such as a formyl group, an acetyl group, a propionyl group, or a butyryl group, a cyano group, and a nitro group.

[0026] Among them, R １１ and R ２１ In view of the copolymerizability of the monomers that give the repeating units (1) and (2), a hydrogen atom or a methyl group is preferred.

[0027] On the other hand, R １２As the group, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 20 carbon atoms is more preferred, an alkyl group having 2 to 10 carbon atoms is preferred, and a branched alkyl group having 3 to 10 carbon atoms is even more preferred. These groups may have a substituent.

[0028] R ２２ As the alkyl group, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms is preferred, and an alkyl group or a phenyl group having 1 to 10 carbon atoms is more preferred. These may have a substituent.

[0029] In the above formulas (1) and (2), L １ and L ２ are preferably each independently a divalent group having a substituted or unsubstituted divalent hydrocarbon group. １ and L ２ The divalent hydrocarbon group in R １１ In the case where the divalent hydrocarbon group has a substituent, examples of the substituent include a group in which one hydrogen atom has been removed from a monovalent hydrocarbon group having 1 to 20 carbon atoms in the formula: １１ , R １２ , R ２１ and R ２２ The substituents mentioned above as examples of the substituents that may be used in the present invention can be suitably employed.

[0030] The above L １ and L ２ The divalent hydrocarbon group in is preferably a divalent aromatic hydrocarbon group, more preferably a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and even more preferably a benzenediyl group or a naphthalenediyl group.

[0031] Among them, L １ and L ２ L is preferably an alkanediyl group obtained by removing one hydrogen atom from an alkyl group having 1 to 10 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a combination thereof, more preferably an alkanediyl group having 1 to 5 carbon atoms, a benzenediyl group, a naphthalenediyl group, or a combination thereof, and even more preferably a benzenediyl group or a combination of a benzenediyl group and a methanediyl group. ２As the alkyl group, a combination of a benzenediyl group and a methanediyl group is particularly preferred.

[0032] The above R １２ and R ２２ may each independently be a monovalent hydrocarbon group having 1 to 20 carbon atoms and containing a fluorine atom. １２ and R ２２ By introducing fluorine atoms into R, the uneven distribution of the repeating units (1) and (2) toward the surface side of the resist underlayer film is promoted, and the solvent resistance and pattern rectangularity of the resist underlayer film can be further improved. １２ and R ２２ are each independently more preferably a monovalent fluorinated alkyl group having 1 to 20 carbon atoms, more preferably a monovalent perfluoroalkyl group having 1 to 10 carbon atoms, and further preferably a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, or a perfluorobutyl group.

[0033] Specific examples of the repeating unit (1) include repeating units represented by the following formulas (1-1) to (1-12).

[0034]

[0035] In the above formulas (1-1) to (1-12), R １１ has the same meaning as the above formula (1). Among these, the repeating units represented by the above formulas (1-4), (1-8) and (1-12) are preferred.

[0036] Specific examples of the repeating unit (2) include repeating units represented by the following formulas (2-1) to (2-9).

[0037]

[0038] In the above formulas (2-1) to (2-9), R ２１ has the same meaning as the above formula (2). Among these, the repeating units represented by the above formulas (2-1), (2-5) and (2-7) are preferred.

[0039] The lower limit of the content of repeating unit (1) or (2) (the total content when both are included) of all repeating units constituting the polymer [A] is preferably 1 mol%, more preferably 5 mol%, even more preferably 10 mol%, and particularly preferably 20 mol%. The upper limit of the content is preferably 100 mol%, more preferably 70 mol%, even more preferably 60 mol%, and particularly preferably 50 mol%. By setting the content of repeating unit (1) or (2) within the above range, high levels of solvent resistance and pattern rectangularity can be achieved.

[0040] The polymer [A] preferably further has a repeating unit represented by the following formula (3) (excluding the cases of the above formulas (1) and (2)) (hereinafter also referred to as "repeating unit (3)"). The polymer [A] may have one or more types of repeating unit (3).

[0041] In the above formula (3), R ３ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ３ is a single bond or a divalent linking group. ４ is a monovalent organic group having 1 to 20 carbon atoms. The term "organic group" refers to a group having at least one carbon atom.

[0042] R ３ The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) and (2) includes R １１ , R １２ , R ２１ and R ２２ The groups exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula can be suitably used.

[0043] L ３ The divalent linking group represented by the formula (1) and (2) includes L １ and L ２ The groups listed as examples of the divalent linking group represented by the following formula can be suitably used. ３ is preferably a single bond.

[0044] R ４The monovalent organic group having 1 to 20 carbon atoms represented by the formula (1) and (2) includes R １１ , R １２ , R ２１ and R ２２ and substituted or unsubstituted monovalent hydrocarbon groups represented by the following formula: ２ Suitable examples include - or -NR'-, or a group containing a combination of two or more of these. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. The substituted or unsubstituted monovalent hydrocarbon group is preferably a substituted or unsubstituted monovalent aromatic hydrocarbon group.

[0045] The substituents that substitute a part or all of the hydrogen atoms of the organic group include R １１ , R １２ , R ２１ and R ２２ Examples of the substituent include the groups listed as the substituents of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the following formula:

[0046] Examples of the heterocyclic group include a group in which one hydrogen atom has been removed from an aromatic heterocyclic structure and a group in which one hydrogen atom has been removed from an alicyclic heterocyclic structure. Five-membered aromatic structures that have aromaticity due to the introduction of heteroatoms are also included in the heterocyclic structure. Examples of heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms.

[0047] Examples of the aromatic heterocyclic structure include: oxygen atom-containing aromatic heterocyclic structures such as furan, pyran, benzofuran, and benzopyran; nitrogen atom-containing aromatic heterocyclic structures such as pyrrole, imidazole, pyridine, pyrimidine, pyrazine, indole, quinoline, isoquinoline, acridine, phenazine, and carbazole; sulfur atom-containing aromatic heterocyclic structures such as thiophene; and aromatic heterocyclic structures containing multiple heteroatoms such as thiazole, benzothiazole, thiazine, and oxazine.

[0048] Examples of the alicyclic heterocyclic structure include oxygen atom-containing alicyclic heterocyclic structures such as oxirane, oxetane, tetrahydrofuran, tetrahydropyran, dioxolane, and dioxane; nitrogen atom-containing alicyclic heterocyclic structures such as aziridine, pyrrolidine, pyrazolidine, piperidine, and piperazine; sulfur atom-containing alicyclic heterocyclic structures such as thietane, thiolane, and thiane; alicyclic heterocyclic structures containing multiple heteroatoms such as oxazoline, morpholine, oxathiolane, oxazine, and thiomorpholine; and structures in which an alicyclic heterocyclic structure and an aromatic ring structure are combined, such as benzoxazine.

[0049] The cyclic structure also includes a lactone structure, a cyclic carbonate structure, a sultone structure, and a structure containing a cyclic acetal.

[0050] Specific examples of the repeating unit (3) include repeating units represented by the following formulas (3-1) to (3-10).

[0051]

[0052] In the above formulas (3-1) to (3-10), R ３ has the same meaning as the above formula (3). Among these, the repeating units represented by the above formulas (3-1) to (3-7) are preferred.

[0053] When the polymer [A] has a repeating unit (3), the lower limit of the content of the repeating unit (3) in all repeating units constituting the polymer [A] (the total content when multiple types are included) is preferably 10 mol%, more preferably 20 mol%, even more preferably 30 mol%, and particularly preferably 40 mol%. The upper limit of the content is preferably 95 mol%, more preferably 90 mol%, even more preferably 80 mol%, and particularly preferably 70 mol%. By setting the content of the repeating unit (3) within the above range, solvent resistance and pattern rectangularity can be exhibited at high levels.

[0054] The polymer (A) may contain, as other repeating units, repeating units derived from maleic acid, maleic anhydride, maleimide derivatives, or the like.

[0055] The lower limit of the weight-average molecular weight of the polymer (A) is preferably 500, more preferably 1000, even more preferably 1500, and particularly preferably 2000. The upper limit of the molecular weight is preferably 10000, more preferably 9000, even more preferably 8000, and particularly preferably 7000. The method for measuring the weight-average molecular weight is as described in the Examples.

[0056] The lower limit of the content of the polymer [A] in the composition for forming a resist underlayer film is preferably 1 mass %, more preferably 2 mass %, even more preferably 3 mass %, and particularly preferably 4 mass %, based on the total mass of the polymer [A] and the solvent [C]. The upper limit of the content is preferably 20 mass %, more preferably 15 mass %, even more preferably 12 mass %, and particularly preferably 10 mass %, based on the total mass of the polymer [A] and the solvent [C].

[0057] The lower limit of the content of the polymer (A) in the components other than the solvent (C) in the composition for forming a resist underlayer film is preferably 10% by mass, more preferably 20% by mass, and even more preferably 30% by mass, and the upper limit of the content is preferably 100% by mass, more preferably 90% by mass, and even more preferably 80% by mass.

[0058] [Method for Synthesizing Polymer [A]] The polymer [A] can be synthesized by radical polymerization, ionic polymerization, polycondensation, polyaddition, addition condensation, etc., depending on the type of monomer. For example, when the polymer [A] is synthesized by radical polymerization, the polymer can be synthesized by polymerizing monomers that provide each structural unit in an appropriate solvent using a radical polymerization initiator, etc.

[0059] Examples of the radical polymerization initiator include azo radical initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, and dimethyl-2,2'-azobis(2-methylpropionate); and peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. These radical initiators can be used alone or in combination of two or more.

[0060] As the solvent used in the polymerization, the solvent [C] described below can be suitably used. These solvents used in the polymerization may be used alone or in combination of two or more kinds.

[0061] The reaction temperature in the polymerization is usually 40° C. to 150° C., preferably 50° C. to 120° C. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

[0062] [Other Polymers] The composition for forming a resist underlayer film may contain, in addition to the polymer [A], a polymer not containing the repeating units (1) and (2) (hereinafter also referred to as "polymer [B]." The composition may contain one or more types of polymer [B].

[0063] The polymer (B) preferably has a repeating unit represented by the following formula (4) (hereinafter also referred to as “repeating unit (4)”). (In formula (4), R ４２ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ４２ is a single bond or a divalent linking group.

[0064] In the above formula (4), R ４２ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １１The groups shown as substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by the following formula, can be suitably used.

[0065] In the above formula (4), L ４２ The divalent linking group represented by the formula (1) is L １ The groups shown as divalent linking groups represented by the following formula can be preferably used. ４２ is preferably a single bond, an alkanediyl group obtained by removing one hydrogen atom from an alkyl group having 1 to 10 carbon atoms, a cycloalkylene group obtained by removing one hydrogen atom from a cycloalkyl group having 5 to 10 carbon atoms, an arylene group obtained by removing one hydrogen atom from a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a carbonyl group, an oxygen atom, or a combination thereof, and more preferably a single bond, an alkanediyl group having 1 to 5 carbon atoms, a cycloalkylene group having 5 to 7 carbon atoms, a phenylene group, a carbonyl group, an oxygen atom, or a combination thereof.

[0066] Specific examples of the repeating unit (4) include repeating units represented by the following formulas (4-1) to (4-8).

[0067]

[0068] In the above formulas (4-1) to (4-8), R ４２ is the same as the above formula (4).

[0069] When the polymer [B] contains the repeating unit (4), the content of the repeating unit (4) in all repeating units constituting the polymer [B] is preferably 10 mol %, more preferably 30 mol %, and even more preferably 50 mol %. The upper limit of the content is preferably 99 mol %, more preferably 90 mol %, and even more preferably 85 mol %.

[0070] The polymer (B) may have a repeating unit represented by the following formula (5) (excluding the case of the above formula (4)) (hereinafter also referred to as “repeating unit (5)”): (In formula (5), R ５３ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ５３ is a single bond or a divalent linking group. ５４is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0071] In the above formula (5), R ５３ and R ５４ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １１ The groups shown as substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by the following formula, can be preferably used. ５３ From the viewpoint of copolymerizability of the monomer that gives the repeating unit (5), R is preferably a hydrogen atom or a methyl group. ５４ R is preferably a monovalent chain hydrocarbon group having 1 to 15 carbon atoms, and more preferably a monovalent branched alkyl group having 1 to 10 carbon atoms. ５３ and R ５４ When R has a substituent, the substituent may be R １１ Suitable examples include the substituents that may be possessed by the following.

[0072] In the above formula (5), L ５３ The divalent linking group represented by the formula (1) is L １ The groups shown as divalent linking groups represented by the following formula can be preferably used. ５３ is preferably a single bond, an alkanediyl group obtained by removing one hydrogen atom from an alkyl group having 1 to 10 carbon atoms, a cycloalkylene group obtained by removing one hydrogen atom from a cycloalkyl group having 5 to 10 carbon atoms, a carbonyl group, an oxygen atom, or a combination thereof, more preferably a single bond, an alkanediyl group having 1 to 5 carbon atoms, a cycloalkylene group having 5 to 7 carbon atoms, a carbonyl group, an oxygen atom, or a combination thereof, and even more preferably a single bond.

[0073] Specific examples of the repeating unit (5) include repeating units represented by the following formulas (5-1) to (5-14).

[0074]

[0075] In the above formulas (5-1) to (5-14), R ５３ is the same as the above formula (5).

[0076] When the polymer [B] contains the repeating unit (5), the content of the repeating unit (5) in all repeating units constituting the polymer [B] is preferably 1 mol %, more preferably 5 mol %, and even more preferably 10 mol %, and the upper limit of the content is preferably 60 mol %, more preferably 40 mol %, and even more preferably 30 mol %.

[0077] The polymer (B) may have a repeating unit represented by the following formula (6) (excluding the cases of the above formula (4) and formula (5)) (hereinafter also referred to as “repeating unit (6)”): (In formula (6), R ６５ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ６４ is a single bond or a divalent linking group. １ is a monovalent group having an aromatic ring with 6 to 20 ring members.

[0078] In this specification, the term "number of ring members" refers to the number of atoms constituting the ring. For example, a biphenyl ring has 12 members, a naphthalene ring has 10 members, and a fluorene ring has 13 members.

[0079] In the above formula (6), R ６５ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １１ The groups shown as substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by the following formula, can be preferably used. ６５ From the viewpoint of copolymerizability of the monomer that gives the repeating unit (6), R is preferably a hydrogen atom or a methyl group. ６５ When R has a substituent, the substituent may be R １１ Suitable examples include the substituents that may be possessed by the following.

[0080] In the above formula (6), L ６４ The divalent linking group represented by the formula (1) is L １ The groups shown as divalent linking groups represented by the following formula can be preferably used. ６４is preferably a single bond, an alkanediyl group obtained by removing one hydrogen atom from an alkyl group having 1 to 10 carbon atoms, a cycloalkylene group obtained by removing one hydrogen atom from a cycloalkyl group having 5 to 10 carbon atoms, a carbonyl group, an oxygen atom, or a combination thereof, more preferably a single bond, an alkanediyl group having 1 to 5 carbon atoms, a cycloalkylene group having 5 to 7 carbon atoms, a carbonyl group, an oxygen atom, or a combination thereof, and even more preferably a single bond.

[0081] In the above formula (4), Ar １ Examples of the aromatic ring having 6 to 20 ring members in Ar include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, and a pyrene ring, aromatic heterocyclic rings such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring, and combinations thereof. １ The aromatic ring is preferably at least one aromatic hydrocarbon ring selected from the group consisting of a benzene ring, a naphthalene ring, an anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, a fluorene ring, a perylene ring, and a coronene ring, and more preferably a benzene ring, a naphthalene ring, or a pyrene ring.

[0082] In the above formula (6), Ar １ As the monovalent group having an aromatic ring with 6 to 20 ring members represented by the formula １ Suitable examples include groups in which one hydrogen atom has been removed from an aromatic ring having 6 to 20 ring members.

[0083] Specific examples of the repeating unit (6) include repeating units represented by the following formulae (6-1) to (6-8).

[0084]

[0085] In the above formulas (6-1) to (6-8), R ６５ has the same meaning as the above formula (6). Among them, the repeating unit represented by the above formula (6-1) is preferred.

[0086] When the polymer [B] contains the repeating unit (6), the content of the repeating unit (6) in all repeating units constituting the polymer [B] is preferably 5 mol %, more preferably 10 mol %, and even more preferably 20 mol %, and the upper limit of the content is preferably 80 mol %, more preferably 70 mol %, and even more preferably 50 mol %.

[0087] The polymer (B) may have a repeating unit represented by the following formula (7) (hereinafter also referred to as “repeating unit (7)”) in addition to or instead of the repeating units (4) to (6). (In formula (7), Ar ５ is a divalent group having an aromatic ring with 5 to 40 ring members. １ is a hydrogen atom or a monovalent organic group having 1 to 60 carbon atoms.

[0088] Ar ５ The aromatic ring having 5 to 40 ring members in the above Ar １ Examples of aromatic rings include aromatic rings in which the aromatic ring having 6 to 20 ring members in the formula (Ar) is extended to have 5 to 40 ring members. ５ Suitable examples of the divalent group having an aromatic ring of 5 to 40 ring members represented by the following formula include groups in which two hydrogen atoms have been removed from the above aromatic ring of 5 to 40 ring members.

[0089] R １ Examples of the monovalent organic group having 1 to 60 carbon atoms represented by the formula (I) include a monovalent hydrocarbon group having 1 to 60 carbon atoms, a group having a divalent heteroatom-containing group between carbon atoms of the hydrocarbon group, a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with a monovalent heteroatom-containing group, and a combination thereof.

[0090] The monovalent hydrocarbon group having 1 to 60 carbon atoms includes R １１ A group in which the monovalent hydrocarbon group having 1 to 20 carbon atoms in the above formula is extended to have a carbon number of 1 to 60 can be suitably used.

[0091] Examples of heteroatoms constituting the divalent or monovalent heteroatom-containing group include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, etc. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0092] Examples of the divalent heteroatom-containing group include -CO-, -CS-, -NH-, -O-, -S-, and combinations of these groups.

[0093] Examples of the monovalent heteroatom-containing group include a hydroxy group, a sulfanyl group, a cyano group, a nitro group, and a halogen atom.

[0094] Specific examples of the repeating unit (7) include repeating units represented by the following formulas (7-1) to (7-3).

[0095]

[0096] The lower limit of the weight-average molecular weight of the polymer (B) is preferably 500, more preferably 1000, even more preferably 2000, and particularly preferably 3000. The upper limit of the molecular weight is preferably 10000, more preferably 9000, even more preferably 8000, and particularly preferably 7000. The method for measuring the weight-average molecular weight is as described in the Examples.

[0097] When the composition for forming a resist underlayer film contains the polymer [B], the lower limit of the content of the polymer [B] is preferably 10 mass %, more preferably 20 mass %, even more preferably 30 mass %, and particularly preferably 40 mass %, based on the total mass of the polymer [A] and the polymer [B]. The upper limit of the content is preferably 90 mass %, more preferably 80 mass %, even more preferably 70 mass %, and particularly preferably 60 mass %, based on the total mass of the polymer [A] and the solvent [C].

[0098] [Method for synthesizing polymer [B]] Polymer [B] can be synthesized in the same manner as polymer [A]. For example, when polymer [B] is synthesized by radical polymerization, it can be synthesized by polymerizing monomers that provide each structural unit in an appropriate solvent using a radical polymerization initiator or the like. Alternatively, Ar５ and aromatic compounds that give R １ The novolak type polymer [B] can be produced by acid addition condensation with an aldehyde or an aldehyde derivative as a precursor to give the following:

[0099] <Solvent (C)> The solvent (C) is not particularly limited as long as it can dissolve or disperse the polymer (A) and any optional components contained as needed.

[0100] Examples of the solvent (C) include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, etc. The solvent (C) can be used alone or in combination of two or more.

[0101] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, and cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene.

[0102] Examples of ester-based solvents include carbonate-based solvents such as diethyl carbonate, acetate monoester-based solvents such as methyl acetate and ethyl acetate, lactone-based solvents such as γ-butyrolactone, polyhydric alcohol partial ether carboxylate-based solvents such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and lactate-based solvents such as methyl lactate and ethyl lactate.

[0103] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, n-propanol, 4-methyl-2-pentanol, and 2,2-dimethyl-1-propanol, and polyalcohol solvents such as ethylene glycol and 1,2-propylene glycol.

[0104] Examples of the ketone solvent include chain ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and 2-heptanone, and cyclic ketone solvents such as cyclohexanone.

[0105] Examples of the ether solvent include chain ether solvents such as n-butyl ether, polyhydric alcohol ether solvents such as cyclic ether solvents such as tetrahydrofuran, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether and propylene glycol monomethyl ether.

[0106] Examples of the nitrogen-containing solvent include chain nitrogen-containing solvents such as N,N-dimethylacetamide, and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0107] The solvent [C] is preferably an alcohol solvent, an ether solvent, or an ester solvent, more preferably a monoalcohol solvent, a polyhydric alcohol partial ether solvent, a polyhydric alcohol partial ether carboxylate solvent, or a lactate ester solvent, and even more preferably 4-methyl-2-pentanol, 2,2-dimethyl-1-propanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, or ethyl lactate.

[0108] The lower limit of the content of the solvent (C) in the composition for forming a resist underlayer film is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70% by mass, and the upper limit of the content is preferably 99.9% by mass, more preferably 99% by mass, and even more preferably 95% by mass.

[0109] [Optional Components] The composition for forming a resist underlayer film may contain optional components within a range that does not impair the effects of the present invention. Examples of optional components include the polymer (B) described above, as well as crosslinking agents, acid generators, dehydrating agents, acid diffusion controllers, surfactants, etc. The optional components may be used alone or in combination of two or more.

[0110] (Crosslinking Agent [D]) The type of crosslinking agent [D] is not particularly limited, and known crosslinking agents can be freely selected and used. Preferably, at least one selected from polyfunctional (meth)acrylates, cyclic ether-containing compounds, glycolurils, diisocyanates, melamines, benzoguanamines, polynuclear phenols, polyfunctional thiol compounds, polysulfide compounds, and sulfide compounds is used as the crosslinking agent. When the composition contains the crosslinking agent [D], crosslinking of the polymer [A] and, if necessary, the polymer [B] can be promoted, thereby improving the solvent resistance of the resist underlayer film.

[0111] The polyfunctional (meth)acrylates are not particularly limited as long as they are compounds having two or more (meth)acryloyl groups, and examples thereof include polyfunctional (meth)acrylates obtained by reacting an aliphatic polyhydroxy compound with (meth)acrylic acid, caprolactone-modified polyfunctional (meth)acrylates, alkylene oxide-modified polyfunctional (meth)acrylates, polyfunctional urethane (meth)acrylates obtained by reacting a (meth)acrylate having a hydroxyl group with a polyfunctional isocyanate, and polyfunctional (meth)acrylates having a carboxyl group obtained by reacting a (meth)acrylate having a hydroxyl group with an acid anhydride.

[0112] Specific examples include trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethylene glycol diisocyan ... Examples of the di(meth)acrylate include cholestyryl di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and bis(2-hydroxyethyl)isocyanurate di(meth)acrylate.

[0113] Examples of cyclic ether-containing compounds include oxiranyl group-containing compounds such as 1,6-hexanediol diglycidyl ether, 3',4'-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate, vinylcyclohexene monoxide, 1,2-epoxy-4-vinylcyclohexene, and 1,2:8,9 diepoxylimonene; and oxetanyl group-containing compounds such as 3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyloxetane, xylylenebisoxetane, and 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane. These cyclic ether-containing compounds can be used alone or in combination of two or more.

[0114] Examples of glycolurils include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril have been methoxymethylated, or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril have been acyloxymethylated, and glycidyl glycolurils.

[0115] Examples of glycidyl glycolurils include 1-glycidyl glycoluril, 1,3-diglycidyl glycoluril, 1,4-diglycidyl glycoluril, 1,6-diglycidyl glycoluril, 1,3,4-triglycidyl glycoluril, 1,3,4,6-tetraglycidyl glycoluril, 1-glycidyl-3a-methyl glycoluril, 1-glycidyl-6a-methyl-glycoluril, 1,3-diglycidyl-3a-methyl glycoluril, 1,4-diglycidyl-3a-methyl glycoluril, 1,6-diglycidyl-3a-methyl glycoluril, 1,3,4-triglycidyl-3a-methyl glycoluril, 1,3,4-triglycidyl-6a-methyl glycoluril, 1,3,4,6-tetraglycidyl-3a-methyl glycoluril, 1-glycidyl-3a,6a-diglycidyl Examples of the glycol uril include methyl glycoluril, 1,3-diglycidyl-3a,6a-dimethyl glycoluril, 1,4-diglycidyl-3a,6a-dimethyl glycoluril, 1,6-diglycidyl-3a,6a-dimethyl glycoluril, 1,3,4-triglycidyl-3a,6a-dimethyl glycoluril, 1,3,4,6-tetraglycidyl-3a,6a-dimethyl glycoluril, 1-glycidyl-3a,6a-diphenyl glycoluril, 1,3-diglycidyl-3a,6a-diphenyl glycoluril, 1,4-diglycidyl-3a,6a-diphenyl glycoluril, 1,6-diglycidyl-3a,6a-diphenyl glycoluril, 1,3,4-triglycidyl-3a,6a-diphenyl glycoluril, and 1,3,4,6-tetraglycidyl-3a,6a-diphenyl glycoluril. These glycolurils can be used alone or in combination of two or more.

[0116] Examples of diisocyanates include 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 3,4-tolylene diisocyanate, 3,5-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and 1,4-cyclohexane diisocyanate.

[0117] Examples of melamines include melamine, monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, hexamethylolmelamine, monobutyrolmelamine, dibutylolmelamine, tributyrolmelamine, tetrabutylolmelamine, pentabutyrolmelamine, hexabutyrolmelamine, and alkylated derivatives of these methylolmelamines or butyrolmelamines. These melamines can be used alone or in combination of two or more.

[0118] Examples of benzoguanamines include benzoguanamines in which the amino group is modified with four alkoxymethyl groups (alkoxymethylol groups) (tetraalkoxymethylbenzoguanamines (tetraalkoxymethylolbenzoguanamines)), such as tetramethoxymethylbenzoguanamine; benzoguanamines in which the amino group is modified with a total of four alkoxymethyl groups (particularly methoxymethyl groups) and a hydroxymethyl group (methylol group); benzoguanamines in which the amino group is modified with three or less alkoxymethyl groups (particularly methoxymethyl groups); benzoguanamines in which the amino group is modified with a total of three or less alkoxymethyl groups (particularly methoxymethyl groups) and a hydroxymethyl group; and the like. These benzoguanamines can be used alone or in combination of two or more.

[0119] Examples of polynuclear phenols include dinuclear phenols such as 4,4'-biphenyldiol, 4,4'-methylenebisphenol, 4,4'-ethylidenebisphenol, and bisphenol A; trinuclear phenols such as 4,4',4"-methylidenetrisphenol, 4,4'-(1-(4-(1-(4-hydroxyphenyl)-1-methylethyl)phenyl)ethylidene)bisphenol, and 4,4'-(1-(4-(1-(4-hydroxy-3,5-bis(methoxymethyl)phenyl)-1-methylethyl)phenyl)ethylidene)bis(2,6-bis(methoxymethyl)phenol); and polyphenols such as novolak. These polynuclear phenols can be used alone or in combination of two or more.

[0120] The polyfunctional thiol compound is a compound having two or more mercapto groups in one molecule, and specific examples thereof include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 2,3-dimercapto-1-propanol, dithioerythritol, 2,3-dimercaptosuccinic acid, 1,2-benzenedithiol, 1,2-benzenedimethanethiol, 1,3-benzenedithiol, 1,3-benzenedimethanethiol, 1,4-benzenedimethanethiol, 3,4-dimercaptotoluene, 4-chloro-1,3-benzenedithiol, 2,4,6-trimethyl-1,3-benzenedimethanethiol, 4,4'-thiodiphenol, 2-hexylamino-4,6-dimercapto-1,3,5-triazine, 2-diethylamino-4,6-dimercapto-1,3,5-triazine, 2-cyclohexylamino-4,6-dimercapto-1,3,5-triazine, 2-di-n-butylamino-4,6-dimercapto-1,3,5-triazine compounds having two mercapto groups such as ethylene glycol bis(3-mercaptopropionate), butanediol bisthioglycolate, ethylene glycol bisthioglycolate, 2,5-dimercapto-1,3,4-thiadiazole, 2,2'-(ethylenedithio)diethanethiol, 2,2-bis(2-hydroxy-3-mercaptopropoxyphenylpropane), 1,2,6-hexanetriol trithioglycolate, 1,3,5-trithiocyanuric acid, trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), and compounds having four or more mercapto groups such as pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(2-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione.These polyfunctional thiol compounds can be used alone or in combination of two or more.

[0121] When the composition for forming a resist underlayer film contains the crosslinking agent [D], the lower limit of the content of the crosslinking agent [D] is preferably 10 parts by mass, more preferably 20 parts by mass, and even more preferably 30 parts by mass, relative to 100 parts by mass of the polymer [A] or 100 parts by mass of the polymer [A] and the polymer [B] combined. The upper limit of the content is preferably 300 parts by mass, more preferably 250 parts by mass, and even more preferably 200 parts by mass.

[0122] [Method for preparing a composition for forming a resist underlayer film] The composition for forming a resist underlayer film can be prepared by mixing the polymer [A], the solvent [C], and, if necessary, any optional components in a predetermined ratio, and preferably filtering the resulting mixture through a membrane filter or the like having a pore size of 0.5 μm or less.

[0123] [Silicon-containing film forming step] In this step, which is carried out before the coating step (I), a silicon-containing film is formed directly or indirectly on a substrate.

[0124] Examples of the substrate include metal or semimetal substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, among which silicon substrates are preferred.The substrate may also be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, or the like is formed.

[0125] The silicon-containing film can be formed by coating a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like. Examples of methods for forming a silicon-containing film by coating a silicon-containing film-forming composition include a method in which the silicon-containing film-forming composition is directly or indirectly applied to a substrate, and the resulting coating film is then cured by exposure and / or heating. Examples of commercially available silicon-containing film-forming compositions include "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all from JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxynitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0126] Examples of radiation used for the exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays and gamma rays, and particle beams such as electron beams, molecular beams and ion beams.

[0127] The lower limit of the temperature when heating the coating film is preferably 90° C., more preferably 150° C., and still more preferably 200° C. The upper limit of the temperature is preferably 550° C., more preferably 450° C., and still more preferably 300° C.

[0128] The lower limit of the average thickness of the silicon-containing film is preferably 1 nm, more preferably 10 nm, and even more preferably 15 nm. The upper limit is preferably 20,000 nm, more preferably 1,000 nm, and even more preferably 100 nm. The average thickness of the silicon-containing film can be measured in the same manner as the average thickness of the resist underlayer film.

[0129] Examples of cases in which a silicon-containing film is formed indirectly on a substrate include cases in which a silicon-containing film is formed on a low dielectric insulating film or an organic underlayer film formed on a substrate.

[0130] [Coating step (I)] In this step, the resist underlayer film-forming composition is coated on the silicon-containing film formed on the substrate.The coating method of the resist underlayer film-forming composition is not particularly limited, and can be carried out by any suitable method such as spin coating, casting coating, roll coating, etc.This forms a coating film, and the resist underlayer film is formed by the evaporation of the solvent [B].

[0131] The lower limit of the average thickness of the resist underlayer film formed is preferably 0.5 nm, more preferably 1 nm, and even more preferably 2 nm. The upper limit of the average thickness is preferably 50 nm, more preferably 20 nm, even more preferably 10 nm, and particularly preferably 7 nm. The average thickness is measured according to the method described in the Examples.

[0132] When the composition for forming a resist underlayer film is applied directly to the substrate, the silicon-containing film forming step may be omitted.

[0133] [Heating Step] Next, the resist underlayer film formed in the coating step (I) is heated. Heating the resist underlayer film promotes deprotection of the sulfonate ester structure in the polymer (A). This step is carried out before the coating step (II).

[0134] The coating film may be heated in an air atmosphere or a nitrogen atmosphere. The lower limit of the heating temperature is 200°C, preferably 210°C, more preferably 220°C, and even more preferably 230°C. The upper limit of the heating temperature is preferably 400°C, more preferably 350°C, and even more preferably 280°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the time is preferably 800 seconds, more preferably 400 seconds, and even more preferably 200 seconds.

[0135] [Coating Step (II)] In this step, a resist film-forming composition is coated onto the resist underlayer film formed in the resist underlayer film-forming composition coating step. The method for coating the resist film-forming composition is not particularly limited, and examples thereof include a rotary coating method.

[0136] To explain this step in more detail, for example, a resist composition is applied so that the resist film to be formed has a predetermined thickness, and then the applied resist film is pre-baked (hereinafter also referred to as "PB") to volatilize the solvent in the applied film, thereby forming the resist film.

[0137] The PB temperature and PB time can be appropriately determined depending on the type of the resist film-forming composition used, etc. The lower limit of the PB temperature is preferably 30°C, more preferably 50°C. The upper limit of the PB temperature is preferably 200°C, more preferably 150°C. The lower limit of the PB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the PB time is preferably 600 seconds, more preferably 300 seconds.

[0138] The resist film-forming composition used in this step is preferably a so-called positive resist film-forming composition for alkali development. Such a resist film-forming composition preferably contains, for example, a resin having an acid-dissociable group and a radiation-sensitive acid generator, and is for exposure with ArF excimer laser light (for ArF exposure) or extreme ultraviolet light (for EUV exposure).

[0139] [Exposure Step] In this step, the resist film formed in the resist film-forming composition application step is exposed to radiation. This step generates a difference in solubility in a basic liquid, which is a developer, between the exposed and unexposed areas of the resist film. More specifically, the solubility of the exposed areas of the resist film in a basic liquid is increased.

[0140] The radiation used for exposure can be appropriately selected depending on the type of the resist film-forming composition used, etc. Examples include visible light, ultraviolet light, far ultraviolet light, electromagnetic waves such as X-rays and gamma rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet light is preferred, and KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F ２ Excimer laser light (wavelength 157 nm), Kr ２Excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm), or extreme ultraviolet light (wavelength 13.5 nm, etc., also referred to as "EUV") is more preferred, and ArF excimer laser light or EUV is even more preferred. The exposure conditions can be appropriately determined depending on the type of resist film-forming composition used, etc.

[0141] Furthermore, in this process, after the exposure, post-exposure baking (hereinafter also referred to as "PEB") can be performed to improve the performance of the resist film, such as resolution, pattern profile, and developability. The PEB temperature and PEB time can be appropriately determined depending on the type of resist film-forming composition used, etc. The lower limit of the PEB temperature is preferably 50°C, more preferably 70°C. The upper limit of the PEB temperature is preferably 200°C, more preferably 150°C. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the PEB time is preferably 600 seconds, more preferably 300 seconds.

[0142] [Development Step] In this step, at least the exposed resist film is developed. In this step, it is preferable to use alkaline development in which the developer used is a basic liquid. Since the exposure step causes a difference in solubility in the basic liquid developer between the exposed and unexposed parts of the resist film, alkaline development removes the exposed parts, which have a relatively high solubility in the basic liquid, thereby forming a resist pattern.

[0143] In the step of developing the exposed resist film, it is preferable to further develop a portion of the resist underlayer film. The resist underlayer film contains a polymer containing sulfonic acid groups, which increases its solubility in a basic liquid developer, allowing it to be removed together with the resist film in the developing step of the resist film. It is sufficient for the resist underlayer film to be developed only partially in the thickness direction from the outermost surface of the resist underlayer film, but it is more preferable for the entire thickness direction to be developed (i.e., the entire resist underlayer film is removed in the exposed area). Although only a portion in the planar direction of the resist underlayer film may be developed, by continuously developing the resist underlayer film with a basic liquid following the resist film, it is possible to omit the etching step of the resist underlayer film, which has been conventionally required, thereby reducing the number of steps, suppressing the influence on other films, etc., and efficiently forming a good resist pattern.

[0144] The basic liquid for alkaline development is not particularly limited, and known basic liquids can be used. Examples of basic liquids for alkaline development include aqueous alkaline solutions containing at least one alkaline compound dissolved therein, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, aqueous TMAH solutions are preferred, and 2.38% by mass aqueous TMAH solutions are more preferred.

[0145] In addition, examples of the developer when organic solvent development is performed include the same as those exemplified above as the solvent (C).

[0146] In this step, washing and / or drying may be carried out after the development.

[0147] [Etching Step] In this step, etching is performed using the resist pattern (and resist underlayer film pattern) as a mask. The etching may be performed once or multiple times, i.e., etching may be performed sequentially using the pattern obtained by etching as a mask. From the viewpoint of obtaining a pattern with a better shape, multiple times is preferred. When etching is performed multiple times, for example, etching is performed sequentially in the order of the silicon-containing film and the substrate. Examples of etching methods include dry etching and wet etching. From the viewpoint of obtaining a better pattern shape on the substrate, dry etching is preferred. For this dry etching, for example, a gas plasma such as oxygen plasma is used. By the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0148] Dry etching can be performed using, for example, a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the mask pattern, the elemental composition of the film to be etched, etc., and can be, for example, CHF ３ , C.F. ４ , C ２ F ６ , C ３ F ８ , SF ６ Fluorine-based gases such as Cl ２ , BCl ３ Chlorine gases such as O ２ , O ３ , H ２ Oxygen-based gases such as O, H ２ , N.H. ３ , CO, CO ２ , C.H. ４ , C ２ H ２ , C ２ H ４ , C ２ H ６ , C ３ H ４ , C ３ H ６ , C ３ H ８ , HF, HI, HBr, HCl, NO, NH ３ , BCl ３ reducing gases such as He, N２ and inert gases such as Ar. These gases may be used in combination. When etching a substrate using the pattern of the resist underlayer film as a mask, a fluorine-based gas is usually used.

[0149] The resist underlayer film-forming composition contains a polymer (A) and a solvent (C). As the resist underlayer film-forming composition, the resist underlayer film-forming composition used in the method for producing a semiconductor substrate can be suitably used.

[0150] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0151] [Weight-average molecular weight (Mw)] The Mw of the polymer was measured by gel permeation chromatography (detector: differential refractometer) using GPC columns (two "G2000HXL" and one "G3000HXL" columns) manufactured by Tosoh Corporation under the following analytical conditions: flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40°C, with monodisperse polystyrene as the standard.

[0152] [Average Film Thickness] The average film thickness was determined by measuring the film thickness at arbitrary nine positions at 5 cm intervals including the center of the resist underlayer film using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D") and calculating the average of these film thicknesses.

[0153] <Synthesis and Acquisition of Monomer> [Synthesis of Styrene Sulfonic Acid Neopentyl Ester] 166 mL of dimethylformamide, 50 g of sodium styrene sulfonate, and 0.5 g of di-tert-butylcatechol were added to a 2 L three-neck flask equipped with a Dimroth condenser, a dropping funnel, and a stirrer bar. 87 mL of thionyl chloride was slowly added dropwise from the dropping funnel under ice cooling, and the mixture was stirred for 3 hours. After stirring, approximately 50 g of ice was added in small increments to decompose the excess thionyl chloride. Then, 100 g of diisopropyl ether was added, and extraction was performed twice. The diisopropyl ether layer was dried over sodium sulfate, and the sodium sulfate was filtered off using a pleated filter paper. The diisopropyl ether solution was concentrated under reduced pressure and weighed to determine the yield. 131.9 g of pyridine and 70 g of neopentyl alcohol were added, and the mixture was stirred under ice cooling for 3 hours. This reaction solution was washed three times with 1N HCl aqueous solution, and further washed with methylene chloride and water to remove pyridine and pyridine hydrochloride. The methylene chloride layer was dried over sodium sulfate, and then the methylene chloride was distilled off under reduced pressure. The golden liquid was purified by silica gel column chromatography using methylene chloride / n-hexane = 2 / 1 to obtain a transparent liquid (yield: 67%). The target product was １ The structure was identified by H-NMR and GC-MS spectra.

[0154] １ H-NMR (CDCl ３ ); 7.87 (d, 2H, Ph), 7.54 (d, 2H, Ph), 6.75 (q, 1H, CH), 5.93 (d, 1H, CH ２ ), 5.48 (d, 1H, CH ２ ), 3.67 (s, 2H, CH ２ ), 0.91 (s, 9H, CH ３ ). GC-MASS (M / Z); 254

[0155] [Ethyl styrenesulfonate] Ethyl styrenesulfonate was obtained from Tosoh Fine Chemicals.

[0156] [Synthesis of 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine-6-carboxaldehyde] 3 g of paraformaldehyde and 30 mL of toluene were added to a 300 mL three-neck flask equipped with a dropping funnel and a Dimroth condenser. 4.66 g of aniline and 10 g of toluene were added dropwise from the dropping funnel, and the mixture was stirred for 30 minutes under ice cooling. Next, 6.1 g of 4-hydroxybenzaldehyde was added to the center of the three-neck flask via filter paper as a solid. The mixture was heated and melted at 95°C for 5 hours under a nitrogen atmosphere and stirred until a homogeneous system was obtained. After completion of the reaction, the reaction solution was concentrated, and 60 mL of methylene chloride was added. 50 mL of 2.5% aqueous sodium hydroxide solution was added, and this washing process was repeated three times. The organic layer was recovered and concentrated, and then the eggplant-shaped flask was immersed in dry ice acetone to precipitate crystals. 20 mL of toluene was added to dissolve the crystals, and the crystals were purified by recrystallization. The resulting crystals were filtered off using a Buchner funnel to obtain 6.4 g of a white solid. １ This was determined by H-NMR.

[0157] １ H-NMR (CDCl ３ ); 9.79 (1H, s, CHO), 7.60 (1H, m, Ph), 7.54 (1H, m, Ph), 7.25 (1H, m, Ph), 7.09 (2H, m, Ph), 6.94 (1H, m, Ph), 6.89 (1H, m, Ph), 5.41 (2H, m, CH ２ ), 4.64 (2H, m, CH ２ ).

[0158] [Synthesis of 6-ethenyl-3-phenyl-3,4-dihydro-2H-1,3-benzoxazine] 12.5 g (35 mmol) of methyltriphenylphosphine bromide and 3.93 g (35 mmol) of potassium t-butoxide were added to a 500 mL three-neck flask equipped with a Dimroth tube and a dropping funnel to obtain a bright yellow slurry ylide reagent. Next, 6 g (25 mmol) of 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine-6-carboxaldehyde and 50 mL of dry THF were added dropwise to precipitate the phosphine oxide and allow the Wittig reaction to proceed. The residue was extracted twice with chloroform, and the chloroform layer was washed four times with water. The organic layer was concentrated and purified by column chromatography (n-hexane / ethyl acetate = 6 / 1). The structure of the target product was confirmed by １ This was determined by H-NMR.

[0159] １ H-NMR (CDCl ３ ); 7.60 (1H, m, Ph), 7.28 (1H, m, Ph), 7.21 (2H, m, Ph), 6.94 (2H, m, Ph), 6.89 (1H, m, Ph), 6.80 (1H, m, Ph), 6.72 (1H, m, CH ２ =CH-), 5.76 (1H, m, CH ２ =CH-), 5.41 (2H, m, CH ２ ), 5.25 (1H, m, CH2=CH-), 4.64 (2H, m, CH ２ ).

[0160] [Synthesis of 4-nonafluorobutylstyrene] 20.1 g of 4-chlorostyrene, 3.65 g of magnesium, and 200 mL of dry THF were added to a 500 mL three-neck flask equipped with a dropping funnel and a Dimroth condenser, and the mixture was heated under reflux for 2 hours. After cooling to approximately 50°C, 51.9 g of 4-iodononafluorobutyl was added, and the Grignard reaction was carried out at 50°C for approximately 1 hour. After completion of the reaction, a 1N aqueous sulfuric acid solution was added to precipitate and settle the magnesium salt. The filtrate was recovered and concentrated, and then purified by column chromatography using ethyl acetate / hexane = 1 / 1 vol % to obtain 28 g of the target product. The structure of the target product was confirmed by １ H-NMR and GC-MASS were used.

[0161] １ H-NMR (CDCl ３ ); 7.67 (2H, d, Ph), 7.28 (2H, d, Ph), 6.72 (1H, q, CH), 5.76 (1H, d, CH ２ ), 5.25 (1H, d, CH ２ ). GC-MASS (m / z)336.

[0162] [Synthesis of styrenesulfonic acid 5-methyl-2-heptaester] 100 mL of dimethylformamide, 30 g of sodium styrenesulfonate, and 0.3 g of di-tert-butylcatechol were added to a 300 mL three-neck flask equipped with a Dimroth condenser, a dropping funnel, and a stirrer bar. 75 mL of thionyl chloride was slowly added dropwise from the dropping funnel under ice cooling, and the mixture was stirred for 3 hours. After stirring, approximately 50 g of ice was added in small increments to decompose the excess thionyl chloride. Then, 100 g of diisopropyl ether was added, and extraction was performed twice. The diisopropyl ether layer was dried over sodium sulfate, and the sodium sulfate was filtered off using a pleated filter paper. The diisopropyl ether solution was concentrated under reduced pressure and weighed to determine the yield. 50.9 g of pyridine and 11.5 g of 5-methyl-2-heptanol were added, and the mixture was stirred under ice cooling for 5 hours. This reaction solution was washed three times with 1N HCl aqueous solution, and further washed with methylene chloride and water to remove pyridine and pyridine hydrochloride. The methylene chloride layer was dried over sodium sulfate, and then the methylene chloride was distilled off under reduced pressure. The golden liquid was purified by silica gel column chromatography using methylene chloride / n-hexane = 1 / 1 to obtain a transparent liquid (yield: 56%). The target product was １ The structure was identified by H-NMR and GC-MS spectra.

[0163] １ H-NMR (400MHz, CDCl ３ ) δ; 7.75 (m, 2H, m-Ph), 7.68 (m, 2H, o-Ph), 6.72 (q, 1H, CH ２ =CH-), 5.76(d,1H,CH ２ =CH-), 5.25(d,1H,CH ２ =CH-), 4.80 (m, 1H, SOOOCH-), 1.62 (m, 1H, -CH-), 1.40-1.39 (m, 5H, CH２ , CH ３ ), 1.19 (m, 2H, -CH ２ -), 0.9(d,6H,CH ３ ). GC-MASS; m / z282

[0164] [Synthesis of vinylbenzyl methanesulfonate ester] 100 mL of methylene chloride and 8.05 g of vinylbenzyl alcohol styrene were added to a 300 mL three-neck flask equipped with a Dimroth condenser, a dropping funnel, and a stirrer bar. Under ice cooling, 8.71 g of methanesulfonic anhydride and 9.50 g of pyridine were slowly added dropwise from the dropping funnel and stirred for 3 hours. The pyridine hydrochloride was then removed, and 100 g of methylene chloride and 200 g of ultrapure water were added, followed by four water washes. The methylene chloride layer was dried over sodium sulfate, the sodium sulfate was filtered off using pleated filter paper, and the methylene chloride was distilled off under reduced pressure. The golden liquid was purified by silica gel column chromatography using a methylene chloride / n-hexane ratio of 1 / 9 to obtain a transparent liquid (yield: 73%). The target product was １ The structure was identified by H-NMR and GC-MS spectra.

[0165] １ H-NMR (400MHz, CDCl ３ ) δ; 7.67 (m, 2H, m-Ph), 7.23 (m, 2H, o-Ph), 6.72 (q, 1H, CH ２ =CH-), 5.76(d,1H,CH ２ =CH-), 5.25(d,1H,CH ２ =CH-), 4.79 (m, 2H, vPhCH ２ -), 3.16 (s, 3H, -CH ３ ). GC-MASS; m / z212

[0166] [Synthesis of vinylbenzyl p-toluenesulfonate] 100 mL of methylene chloride and 8.05 g of vinylbenzyl alcohol styrene were added to a 300 mL three-neck flask equipped with a Dimroth condenser, a dropping funnel, and a stirrer bar. Under ice cooling, 9.53 g of p-toluenesulfonic acid chloride and 9.50 g of pyridine were slowly added dropwise from the dropping funnel and stirred for 3 hours. The pyridine hydrochloride was then removed, and 100 g of methylene chloride and 200 g of ultrapure water were added, followed by washing with water four times. The methylene chloride layer was dried over sodium sulfate, the sodium sulfate was filtered off using pleated filter paper, and the methylene chloride was distilled off under reduced pressure. The golden liquid was purified by silica gel column chromatography using a methylene chloride / n-hexane = 1 / 9 mixture to obtain a transparent liquid (yield: 73%). The target product was １ The structure was identified by H-NMR and GC-MS spectra.

[0167] １ H-NMR (400MHz, CDCl ３ ) δ; 7.75 (m, 2H, m-Ph) 7.67 (m, 2H, m-Ph), 7.45 (m, 2H, m-Ph), 7.23 (m, 2H, o-Ph), 6.72 (q, 1H, CH ２ =CH-), 5.76(d,1H,CH ２ =CH-), 5.25(d,1H,CH ２ =CH-), 4.79 (m, 2H, vPhCH ２ -), 2.43(s, 3H, -CH ３ ). GC-MASS; m / z289

[0168] [Synthesis of vinylbenzyl trifluoromethanesulfonate] 100 mL of methylene chloride and 8.05 g of vinylbenzyl alcohol styrene were added to a 300 mL three-neck flask equipped with a Dimroth condenser, a dropping funnel, and a stirrer bar. Under ice cooling, 8.42 g of trifluoromethanesulfonyl chloride and 9.50 g of pyridine were slowly added dropwise from the dropping funnel, and the mixture was stirred for 3 hours. The pyridine hydrochloride was then removed, and 100 g of methylene chloride and 200 g of ultrapure water were added, followed by four water washes. The methylene chloride layer was dried over sodium sulfate, the sodium sulfate was filtered off using pleated filter paper, and the methylene chloride was distilled off under reduced pressure. The golden liquid was purified by silica gel column chromatography using a methylene chloride / n-hexane ratio of 1 / 9 to obtain a transparent liquid (yield: 68%). The target product was １ The structure was identified by H-NMR and GC-MS spectra.

[0169] １ H-NMR (400MHz, CDCl ３ ) δ; 7.67 (m, 2H, m-Ph), 7.23 (m, 2H, o-Ph), 6.72 (q, 1H, CH ２ =CH-), 5.76(d,1H,CH ２ =CH-), 5.25(d,1H,CH ２ =CH-), 4.79 (m, 2H, vPhCH ２ -) GC-MASS; m / z266

[0170] <Synthesis of Polymer [A]> Each polymer [A] was synthesized according to the procedure shown below. In the formulas shown in the synthesis examples below, the number attached to each repeating unit indicates the content (mol %) of that repeating unit. When no number is attached to a repeating unit, the content of that repeating unit is 100 mol %. The composition ratio is １３ This was confirmed by C-NMR.

[0171] Synthesis Example 1-1 (Synthesis of Polymer (A-1)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 7.63 g of styrenesulfonic acid neopentyl ester, 1.39 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.4 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 7.50 g (yield: 98%) of polymer (A-1) represented by the following formula as a white solid. The resulting polymer (A-1) had Mw: 4440, Mn: 2670, and PDI (dispersity index): 1.66.

[0172]

[0173] Synthesis Example 1-2 (Synthesis of Polymer (A-2)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 6.36 g of styrenesulfonic acid ethyl ester, 1.38 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.4 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.20 g (yield: 97%) of polymer (A-2) represented by the following formula as a white solid. The resulting polymer (A-2) had Mw: 4250, Mn: 2390, and PDI: 1.77.

[0174]

[0175] Synthesis Example 1-3 Synthesis of Polymer (A-3) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 8.46 g of styrenesulfonic acid 5-methyl-2-heptaester, 1.38 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol, yielding 8 g (yield: 95%) of polymer (A-3) represented by the following formula as a white solid. The resulting polymer (A-3) had Mw: 4520, Mn: 2430, and PDI: 1.86.

[0176]

[0177] Synthesis Example 1-4 (Synthesis of Polymer (A-4)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 4.34 g of styrenesulfonic acid neopentyl ester, 2.66 g of styrene, 1.96 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 2.5 g (yield: 36%) of polymer (A-4) represented by the following formula as a white solid. The resulting polymer (A-4) had Mw: 3680, Mn: 1980, and PDI: 1.86.

[0178]

[0179] Synthesis Example 1-5 (Synthesis of Polymer (A-5)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 3.45 g of styrenesulfonic acid neopentyl ester, 3.57 g of tert-butoxystyrene, 1.55 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.50 g (yield: 93%) of polymer (A-5) represented by the following formula as a white solid. The resulting polymer (A-5) had Mw: 4120, Mn: 2180, and PDI: 1.89.

[0180]

[0181] Synthesis Example 1-6 (Synthesis of Polymer (A-6)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 2.92 g of styrenesulfonic acid neopentyl ester, 4.08 g of 6-ethenyl-3-phenyl-3,4-dihydro-2H-1,3-benzoxazine, 1.32 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.0 g (yield: 86%) of polymer (A-6) represented by the following formula as a white solid. The resulting polymer (A-6) had Mw: 4020, Mn: 2670, and PDI: 1.51.

[0182]

[0183] Synthesis Example 1-7 Synthesis of Polymer (A-7) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 4.45 g of styrenesulfonic acid neopentyl ester, 2.55 g of isopropenyloxazoline, 2.02 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 4.3 g (yield: 61%) of polymer (A-7) represented by the following formula as a white solid. The resulting polymer (A-7) had Mw: 4170, Mn: 2270, and PDI: 1.84.

[0184]

[0185] Synthesis Example 1-8 Synthesis of Polymer (A-8) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 3.43 g of styrenesulfonic acid neopentyl ester, 3.57 g of 4-vinylglycidylphenyl ether, 1.55 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.60 g (yield: 94%) of polymer (A-8) represented by the following formula as a white solid. The resulting polymer (A-8) had Mw: 4320, Mn: 2720, and PDI: 1.59.

[0186]

[0187] Synthesis Example 1-9 (Synthesis of Polymer (A-9)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 3.74 g of styrenesulfonic acid neopentyl ester, 3.26 g of 4-vinylbenzyl methyl ether, 1.69 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.90 g (yield: 99%) of polymer (A-9) represented by the following formula as a white solid. The resulting polymer (A-9) had Mw: 4720, Mn: 2890, and PDI: 1.63.

[0188]

[0189] Synthesis Example 1-10 (Synthesis of Polymer (A-10)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 2.41 g of styrenesulfonic acid neopentyl ester, 4.59 g of 4-nonafluorobutylstyrene, 1.09 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 4.8 g (yield: 67%) of polymer (A-10) represented by the following formula as a white solid. The resulting polymer (A-10) had Mw: 4570, Mn: 2890, and PDI: 1.58.

[0190]

[0191] Synthesis Example 1-11 (Synthesis of Polymer (A-11)) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 2.84 g of styrenesulfonic acid neopentyl ester, 2.69 g of 4-nonafluorobutylstyrene, 1.47 g of tert-butoxystyrene, 1.28 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 5.5 g (yield: 79%) of polymer (A-11) represented by the following formula as a white solid. The resulting polymer (A-11) had Mw: 3890, Mn: 2090, and PDI: 1.86.

[0192]

[0193] Synthesis Example 1-12 Synthesis of Polymer (A-12) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 4.22 g of styrenesulfonic acid nonafluorobutyl ester, 2.78 g of tert-butoxystyrene, 1.21 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 3.80 g (yield: 54%) of polymer (A-12) represented by the following formula as a white solid. The resulting polymer (A-12) had Mw: 4010, Mn: 2240, and PDI: 1.79.

[0194]

[0195] Synthesis Example 1-13 Synthesis of Polymer (A-13) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 7.00 g of 4-vinylbenzyl methanesulfonate, 1.52 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.8 g (yield: 97%) of polymer (A-13) represented by the following formula as a white solid. The resulting polymer (A-13) had Mw: 4240, Mn: 2570, and PDI: 1.65.

[0196]

[0197] Synthesis Example 1-14 Synthesis of Polymer (A-14) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 7.00 g of 4-vinylbenzyl-p-toluenesulfonate, 1.12 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.9 g (yield: 99%) of polymer (A-14) represented by the following formula as a white solid. The resulting polymer (A-14) had Mw: 4340, Mn: 2580, and PDI: 1.68.

[0198]

[0199] Synthesis Example 1-15 Synthesis of Polymer (A-15) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 7.00 g of 4-vinylbenzyl trifluoromethanesulfonate, 1.21 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.9 g (yield: 99%) of polymer (A-15) represented by the following formula as a white solid. The resulting polymer (A-1) had Mw: 4530, Mn: 2680, and PDI: 1.69.

[0200]

[0201] Synthesis Example 1-16 Synthesis of Polymer (A-16) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 3.51 g of 4-vinylbenzyl trifluoromethanesulfonate, 3.49 g of 4-tert-butylstyrene, 1.52 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.3 g (yield: 90%) of polymer (A-16) represented by the following formula as a white solid. The resulting polymer (A-16) had Mw: 4320, Mn: 2420, and PDI: 1.79.

[0202]

[0203] Synthesis Example 1-17 Synthesis of Polymer (A-17) 10 g of dimethylformamide was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 3.66 g of 4-vinylbenzyl-p-toluenesulfonate, 3.34 g of 4-tert-butylstyrene, 1.46 g of dimethyl-2,2-azobis(2-methylpropionate), and 20.0 g of dimethylformamide was added dropwise from a feeder over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation with a 10-fold amount of methanol to obtain 6.4 g (yield: 92%) of polymer (A-17) represented by the following formula as a white solid. The resulting polymer (A-17) had Mw: 4670, Mn: 2520, and PDI: 1.85.

[0204]

[0205] Synthesis Example 1-18 Synthesis of Polymer (A-18) 6 g of methyl isobutyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 80°C. A mixed solution of 2.75 g of acrylic acid benzenesulfonic acid neopentyl ester, 1.60 g of N-phenylmaleimide, 1.65 g of vinylbenzyl alcohol, 1.42 g of dimethyl-2,2-azobis(2-methylpropionate), and 12 g of methyl isobutyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymer solution was purified by precipitation into a 10-fold amount of methanol to obtain Polymer (A-18) represented by the following formula as a white solid. The resulting Polymer (A-18) had an Mw of 7,400, an Mn of 4,370, and a PDI of 1.69.

[0206]

[0207] Synthesis Example 1-19 (Synthesis of Polymer (A-19)) 6 g of methyl isobutyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 0°C. A mixed solution of 3.06 g of acrylic acid 3-trifluoromethylbenzenesulfonic acid neopentyl ester, 1.45 g of N-phenylmaleimide, 1.49 g of vinylbenzyl alcohol, 1.28 g of dimethyl-2,2-azobis(2-methylpropionate), and 12 g of methyl isobutyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The obtained polymerization solution was precipitated and purified in a 10-fold amount of methanol to obtain Polymer (A-19) represented by the following formula as a white solid. The obtained Polymer (A-19) had an Mw of 7,860, an Mn of 4,530, and a PDI of 1.74.

[0208]

[0209] Synthesis Example 1-20 (Synthesis of Polymer (A-20)) 6 g of methyl isobutyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 0°C. A mixed solution of 3.31 g of acrylic acid 3,5-trifluoromethylbenzenesulfonic acid neopentyl ester, 1.32 g of N-phenylmaleimide, 1.37 g of vinylbenzyl alcohol, 1.17 g of dimethyl-2,2-azobis(2-methylpropionate), and 12 g of methyl isobutyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The resulting polymerization solution was purified by precipitation into a 10-fold amount of methanol to obtain Polymer (A-20) represented by the following formula as a white solid. The resulting Polymer (A-20) had an Mw of 8090, an Mn of 4980, and a PDI of 1.62.

[0210]

[0211] Synthesis Example 1-21 (Synthesis of Polymer (A-21)) 6 g of methyl isobutyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 0°C. A mixed solution of 2.39 g of styrenesulfonic acid neopentyl ester, 1.63 g of N-phenylmaleimide, 1.98 g of 3-propargyloxystyrene, 1.44 g of dimethyl-2,2-azobis(2-methylpropionate), and 12 g of methyl isobutyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The obtained polymerization solution was purified by precipitation into a 10-fold amount of methanol to obtain Polymer (A-21) represented by the following formula as a white solid. The obtained Polymer (A-21) had an Mw of 7820, an Mn of 4820, and a PDI of 1.62.

[0212]

[0213] Synthesis Example 1-22 (Synthesis of Polymer (A-22)) 6 g of methyl isobutyl ketone was placed in a three-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer bar and maintained at 0°C. A mixed solution of 2.62 g of acrylic acid benzenesulfonic acid neopentyl ester, 1.52 g of N-phenylmaleimide, 1.85 g of 3-propargyloxystyrene, 1.35 g of dimethyl-2,2-azobis(2-methylpropionate), and 12 g of methyl isobutyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 80°C for 3 hours. The obtained polymerization solution was precipitated and purified in a 10-fold amount of methanol to obtain Polymer (A-22) represented by the following formula as a white solid. The obtained Polymer (A-22) had an Mw of 7750, an Mn of 4860, and a PDI of 1.59.

[0214]

[0215] <Synthesis of Polymer [B]> Polymers represented by the following formulae (B-1) to (B-3) (hereinafter also referred to as "Polymer (B-1)") were synthesized according to the procedure described below.

[0216]

[0217] Synthesis Example 2-1 (Synthesis of Polymer (B-1)) 63 g of acrylic acid, 36 g of 2-ethylhexyl acrylate, and 21.2 g of dimethyl 2,2'-azobis(2-methylpropionate) were added to prepare a monomer solution. 300 g of methyl isobutyl ketone was placed in a reaction vessel under a nitrogen atmosphere, and the mixture was heated to 80°C. While stirring, the monomer solution was added dropwise over 3 hours. The start of the dropwise addition marked the start of the polymerization reaction. After the polymerization reaction was carried out for 6 hours, the mixture was cooled to 30°C or below. 300 g of propylene glycol monomethyl ether was added to the reaction solution, and the methyl isobutyl ketone was removed by concentration under reduced pressure, yielding a propylene glycol monomethyl ether solution of polymer (B-1). The Mw of polymer (B-1) was 6,500.

[0218] Synthesis Example 2-2 (Synthesis of Polymer (B-2)) 66 g of acrylic acid, 34 g of styrene, and 25.1 g of dimethyl 2,2'-azobis(2-methylpropionate) were added to prepare a monomer solution. 300 g of methyl isobutyl ketone was placed in a reaction vessel under a nitrogen atmosphere, and the mixture was heated to 80°C. While stirring, the monomer solution was added dropwise over 3 hours. The start of the dropwise addition marked the start of the polymerization reaction. After the polymerization reaction was carried out for 6 hours, the mixture was cooled to 30°C or below. 300 g of propylene glycol monomethyl ether was added to the reaction solution, and the methyl isobutyl ketone was removed by concentration under reduced pressure, yielding a propylene glycol monomethyl ether solution of polymer (B-2). The Mw of polymer (B-2) was 5,300.

[0219] Synthesis Example 2-3 (Synthesis of Polymer (B-3)) A reaction vessel was charged with 29.1 g of 2,7-dihydroxynaphthalene, 14.8 g of a 37% by mass formaldehyde solution, and 87.3 g of methyl isobutyl ketone under a nitrogen atmosphere and dissolved. 1.0 g of p-toluenesulfonic acid monohydrate was added to the reaction vessel, and the mixture was heated to 85°C and reacted for 4 hours. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and 200 g of methyl isobutyl ketone and 400 g of water were added to wash the organic phase. After separating the aqueous phase, the resulting organic phase was concentrated using an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 100 g of methanol. The precipitate was then dried at 60°C for 12 hours using a vacuum dryer to obtain polymer (b-3) represented by the following formula (b-3). The Mw of polymer (b-3) was 3,400.

[0220]

[0221] To a reaction vessel, under a nitrogen atmosphere, 16.8 g of the polymer (b-3), 34.9 g of propargyl bromide, 90 g of methyl isobutyl ketone, and 45.0 g of methanol were added and stirred. Then, 106.9 g of a 25% by mass aqueous solution of tetramethylammonium hydroxide was added, and the reaction was carried out at 50°C for 6 hours. The reaction solution was cooled to 30°C, and 200.0 g of a 5% by mass aqueous solution of oxalic acid was added. After removing the aqueous phase, the resulting organic phase was concentrated using an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 100 g of methanol. The mixture was then dried at 60°C for 12 hours using a vacuum dryer to obtain polymer (B-3). The Mw of polymer (B-3) was 3,000.

[0222] <Preparation of Composition> [A] polymer, [B] polymer, [C] solvent, [D] crosslinking agent, [E] acid generator, and [F] dehydrating agent used in the preparation of the composition are shown below.

[0223] [[A] Polymer] Polymers (A-1) to (A-22) synthesized above

[0224] [[B] Polymer] Polymers (B-1) to (B-3) synthesized above

[0225] [[C] Solvent] C-1: Propylene glycol monomethyl ether acetate C-2: Propylene glycol monomethyl ether C-3: 4-methyl-2-pentanol C-4: Ethyl lactate C-5: 2,2-dimethyl-1-propanol

[0226] [[D] Crosslinking Agent] D-1: Compound represented by the following formula (D-1) D-2: Compound represented by the following formula (D-2) D-3: Compound represented by the following formula (D-3)

[0227]

[0228] [[E] Acid Generator] E-1: Compound represented by the following formula (E-1): E-2: Compound represented by the following formula (E-2): E-3: Compound represented by the following formula (E-3):

[0229]

[0230] [[F] Dehydrating agent] F-1: Trimethyl orthoformate

[0231] [Example 1] 50 parts by mass of (A-1) as the polymer [A] and 50 parts by mass of (D-1) as the crosslinking agent [D] were dissolved in 1,100 parts by mass of (C-1) and 200 parts by mass of (C-2) as the solvent [C]. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare composition (J-1).

[0232] Examples 2 to 35 and Comparative Examples 1 to 3 Compositions (J-2) to (J-35) and (CJ-1) to (CJ-3) were prepared in the same manner as in Example 1, except that the types and amounts of each component were used as shown in Table 1 below. In Table 1, a "-" in the "A, B, D, E, F" column indicates that the corresponding component was not used.

[0233]

[0234] <Evaluation> Using the compositions prepared above, the solvent resistance and the rectangularity of the resist pattern formed by EUV exposure were evaluated by the following methods. The evaluation results are shown in Table 2 below.

[0235] [Solvent Resistance] The composition prepared above was applied to a 12-inch silicon wafer by spin coating using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12"). Next, the wafer was heated at 250°C for 60 seconds in an air atmosphere, and then cooled at 23°C for 60 seconds to form a resist underlayer film with an average thickness of 5 nm, thereby obtaining a substrate with a resist underlayer film formed on the substrate. The obtained substrate with a resist underlayer film was immersed in cyclohexanone (23°C) for 1 minute. The average film thicknesses before and after immersion were measured. The absolute value of the value obtained by the equation (X-X0) x 100 / X0 was calculated, where X0 is the average thickness of the resist underlayer film before immersion and X is the average thickness of the resist underlayer film after immersion, and this was used as the film thickness change rate (%). The solvent resistance was evaluated as "A" (good) when the film thickness change rate was less than 1%, "B" (fairly good) when it was 1% or more but less than 10%, and "C" (poor) when it was 10% or more.

[0236] <Preparation of Resist Composition> Resist composition (R-1) was obtained by mixing 100 parts by mass of a polymer having a structural unit (1) derived from 4-hydroxystyrene, a structural unit (2) derived from styrene, and a structural unit (3) derived from 4-t-butoxystyrene (the proportions of the structural units were (1) / (2) / (3)=65 / 5 / 30 (mol %)), 1.0 part by mass of triphenylsulfonium trifluoromethanesulfonate as a radiation-sensitive acid generator, and 4,400 parts by mass of ethyl lactate and 1,900 parts by mass of propylene glycol monomethyl ether acetate as solvents, and filtering the resulting solution through a filter with a pore size of 0.2 μm.

[0237] [Pattern Rectangularity (EUV Exposure)] An organic underlayer film forming material (JSR Corporation's "HM8006") was applied to a 12-inch silicon wafer by a spin coating method using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12"), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. A silicon-containing film-forming composition (JSR Corporation's "NFC SOG080") was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a silicon-containing film with an average thickness of 20 nm. The composition prepared above was applied to the silicon-containing film formed above to form a resist underlayer film. The resist underlayer film formed above was heated at 250°C for 90 seconds, and then cooled at 23°C for 30 seconds to obtain a resist underlayer film with an average thickness of 5 nm. Resist composition (R-1) was applied onto the resist underlayer film formed above, heated at 130°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. The resist film was irradiated with extreme ultraviolet light using a NXE:3300B (NA 0.3, sigma 0.9, quadrupole illumination, 1:1 line and space mask with a line width of 16 nm on the wafer). After irradiation with extreme ultraviolet light, the substrate was heated at 110°C for 60 seconds and then cooled at 23°C for 60 seconds. The resist film was then developed using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (20°C to 25°C) by the puddle method, washed with water, and dried to obtain an evaluation substrate on which a resist pattern was formed. A scanning electron microscope (Hitachi High-Technologies Corporation's "SU8220") was used to measure and observe the resist pattern on the evaluation substrate. The pattern rectangularity was evaluated as "A" (good) if the cross-sectional shape of the pattern was rectangular, "B" (fairly good) if there was a footing on the cross-section of the pattern, and "C" (poor) if there was a residue (defect) on the pattern.

[0238]

[0239] <Evaluation> Using the compositions prepared above, the rectangularity of resist patterns obtained by KrF exposure was evaluated by the following method. The evaluation results are shown in Table 3 below.

[0240] [Pattern Rectangularity (KrF Exposure)] An organic underlayer film forming material ("HM8006" manufactured by JSR Corporation) was applied to a 12-inch silicon wafer by a spin coating method using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. A silicon-containing film-forming composition ("NFC SOG800" manufactured by JSR Corporation) was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a silicon-containing film with an average thickness of 20 nm. The composition prepared above was applied to the silicon-containing film formed above to form a resist underlayer film. The resist underlayer film formed above was heated at 250°C for 90 seconds, and then cooled at 23°C for 30 seconds to obtain a resist underlayer film with an average thickness of 5 nm. Resist composition (R-1) was applied onto the resist underlayer film, heated at 130°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. The resist film was irradiated with KrF using a 1:1 line-and-space mask with inner 0.75, outer 0.91, dipole illumination, and a linewidth of 130 nm on the wafer. After irradiation with KrF radiation, the substrate was heated at 110°C for 60 seconds and then cooled at 23°C for 60 seconds. The resist film was then developed using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (20°C to 25°C) by the puddle method, washed with water, and dried to obtain an evaluation substrate with a resist pattern formed thereon. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG5000") was used to measure and observe the resist pattern on the evaluation substrate. The pattern rectangularity was evaluated as "A" (good) if the cross-sectional shape of the pattern was rectangular, "B" (fairly good) if there was a footing on the cross-section of the pattern, and "C" (poor) if there were residues (defects) on the pattern.

[0241]

[0242] <Evaluation> Using the compositions prepared above, the rectangularity of the resist patterns obtained by EB exposure was evaluated by the following method. The evaluation results are shown in Table 4 below.

[0243] [Pattern Rectangularity (EB Exposure)] An organic underlayer film forming material ("HM8006" manufactured by JSR Corporation) was applied to a 12-inch silicon wafer by a spin coating method using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. A silicon-containing film-forming composition ("NFC SOG800" manufactured by JSR Corporation) was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a silicon-containing film with an average thickness of 20 nm. The composition prepared above was applied to the silicon-containing film formed above to form a resist underlayer film. The resist underlayer film formed above was heated at 250°C for 60 seconds, and then cooled at 23°C for 30 seconds to obtain a resist underlayer film with an average thickness of 5 nm. Resist composition (R-1) was coated on the resist underlayer film, heated at 130° C. for 60 seconds, and then cooled at 23° C. for 30 seconds to form a resist film with an average thickness of 50 nm. Next, the photoresist layer was exposed using an EB scanner (electron beam lithography system (ELS-F150 manufactured by Elionix, current 1 pA, voltage 150 kV, pattern size 200 nm). After irradiation with the electron beam, the substrate was heated at 110°C for 60 seconds and then cooled at 23°C for 60 seconds. Thereafter, the substrate was developed by the puddle method using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (20°C to 25°C), and then washed with water and dried to obtain an evaluation substrate on which a resist pattern was formed. A scanning electron microscope (CG5000 manufactured by Hitachi High-Technologies Corporation) was used to measure and observe the resist pattern of the evaluation substrate. The pattern rectangularity was evaluated as "A" (good) when the cross-sectional shape of the pattern was rectangular, "B" (fairly good) when there was a footing on the cross section of the pattern, and "C" (poor) when there was a residue (defect) in the pattern.

[0244]

[0245] <Evaluation> Using the compositions prepared above, the rectangularity of resist patterns obtained by EUV exposure was evaluated by the following method. The evaluation results are shown in Table 5 below.

[0246] <Preparation of EUV Exposure Resist Composition (R-2)> Compound (S-1) used in preparing EUV exposure resist composition (R-2) was synthesized according to the procedure shown below. In a reaction vessel, 6.5 parts by mass of isopropyltin trichloride was added to 150 mL of 0.5 N aqueous sodium hydroxide solution while stirring, and the reaction was carried out for 2 hours. The precipitate that formed was collected by filtration, washed twice with 50 parts by mass of water, and then dried to obtain compound (S-1). Compound (S-1) was a hydroxide oxide product (i-PrSnO) of the hydrolysis product of isopropyltin trichloride. （３／２－ｘ／２） (OH) ｘ (where 0<x<3 is the structural unit).

[0247] 2 parts by mass of the compound (S-1) synthesized above and 98 parts by mass of propylene glycol monoethyl ether were mixed, and the resulting mixture was passed through an activated 4 Å molecular sieve to remove residual water, followed by filtration through a filter with a pore size of 0.2 μm to prepare a resist composition for EUV exposure (R-2).

[0248] [Pattern Rectangularity (EUV Exposure)] An organic underlayer film-forming material ("HM8006" manufactured by JSR Corporation) was applied onto a 12-inch silicon wafer by spin coating using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. The resist underlayer film-forming composition prepared above was applied onto this organic underlayer film, and then heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist underlayer film with an average thickness of 5 nm. Resist composition (R-2) for EUV exposure was applied onto this resist underlayer film by spin coating using the spin coater, and after a predetermined time had elapsed, the resist film was heated at 90°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 35 nm. The resist film was exposed to light using an EUV scanner (ASML's "TWINSCAN NXE:3300B" (NA 0.3, sigma 0.9, quadrupole illumination, 1:1 line and space mask with on-wafer line width of 16 nm). After exposure, the substrate was heated at 110°C for 60 seconds and then cooled at 23°C for 60 seconds. Thereafter, the substrate was developed by a puddle method using 2-heptanone (20 to 25°C) and then dried to obtain an evaluation substrate on which a resist pattern was formed. A scanning electron microscope (Hitachi High-Tech's "CG-6300") was used to measure and observe the resist pattern of the evaluation substrate. The pattern rectangularity was evaluated as "A" (good) when the cross-sectional shape of the pattern was rectangular, and as "B" (poor) when there was a footing on the cross section of the pattern.

[0249]

[0250] As can be seen from the results in Tables 2 to 5, the resist underlayer films formed from the compositions of the Examples were superior in solvent resistance and pattern rectangularity compared to the resist underlayer films formed from the compositions of the Comparative Examples.

[0251] According to the method for producing a semiconductor substrate of the present invention, a composition for forming a resist underlayer film capable of forming a resist underlayer film having excellent solvent resistance and pattern rectangularity is used, thereby enabling efficient production of semiconductor substrates. The composition for forming a resist underlayer film of the present invention enables the formation of a film having excellent solvent resistance and pattern rectangularity. Therefore, these compositions can be suitably used in the production of semiconductor devices, etc.

Claims

1. a polymer having a sulfonate ester structure; Solvent and A composition for forming a resist underlayer film, comprising:

2. 2. The composition for forming a resist underlayer film according to claim 1, wherein the polymer has at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): 【Chemical 1】 (In formulas (1) and (2), R １１ and R ２１ are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. １２ and R ２２ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. １ is a single bond or a divalent linking group. ２ is a divalent linking group.

3. The above L １ and L ２ The composition for forming a resist underlayer film according to claim 2 , wherein each independently represents a divalent group having a substituted or unsubstituted divalent hydrocarbon group.

4. The above L １ and L ２ 4. The composition for forming a resist underlayer film according to claim 3, wherein the divalent hydrocarbon group is a divalent aromatic hydrocarbon group.

5. The above R １２ and R ２２ The composition for forming a resist underlayer film according to any one of claims 2 to 4, wherein each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms and having a fluorine atom.

6. The composition for forming a resist underlayer film according to any one of claims 2 to 4, wherein the polymer further has a repeating unit represented by the following formula (3) (excluding the cases of the above formulas (1) and (2)): 【Chemistry 2】 (In formula (3), R ３ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ３ is a single bond or a divalent linking group. ４ is a monovalent organic group having 1 to 20 carbon atoms.

7. The above L ３ is a single bond, and the R ４ The composition for forming a resist underlayer film according to claim 6 , wherein is a substituted or unsubstituted monovalent aromatic hydrocarbon group or a substituted or unsubstituted monovalent heterocyclic group.

8. The composition for forming a resist underlayer film according to any one of claims 2 to 4, wherein the content of at least one selected from the group consisting of the repeating unit represented by formula (1) and the repeating unit represented by formula (2) is 1 mol % or more and 70 mol % or less of all repeating units constituting the polymer.

9. 5. The composition for forming a resist underlayer film according to claim 1, wherein the polymer is a block copolymer.

10. The composition for forming a resist underlayer film according to any one of claims 1 to 4, further comprising a crosslinking agent.

11. The composition for forming a resist underlayer film according to any one of claims 1 to 4, wherein the content of the polymer in the composition for forming a resist underlayer film other than the solvent is 10 mass% or more.

12. A step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate; a step of applying a composition for forming a resist film to the resist underlayer film formed in the above-mentioned step of applying the composition for forming a resist underlayer film; a step of exposing the resist film formed in the resist film-forming composition application step to radiation; a step of developing at least the exposed resist film; Equipped with The composition for forming a resist underlayer film, a polymer having a sulfonate ester structure; Solvent and A method for manufacturing a semiconductor substrate, comprising:

13. A method for manufacturing a semiconductor substrate as described in claim 12, wherein the polymer has at least one repeating unit selected from the group consisting of repeating units represented by the following formula (1) and repeating units represented by the following formula (2): 【Chemistry 3】 (In formulas (1) and (2), R 11 and R 21 each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R 12 and R 22 each independently represent a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. L 1 represents a single bond or a divalent linking group. L 2 represents a divalent linking group.)

14. A method for manufacturing a semiconductor substrate as described in claim 12 or claim 13, further comprising a step of heating the resist underlayer film formed by the resist underlayer film forming composition coating step at 200°C or higher before the resist film forming composition coating step.

15. The method for manufacturing a semiconductor substrate according to claim 12 or claim 13, wherein the radiation is a KrF excimer laser, an electron beam or extreme ultraviolet light.

16. A method for manufacturing a semiconductor substrate as described in claim 12 or claim 13, wherein the film thickness of the resist underlayer film is 20 nm or less.

17. A method for manufacturing a semiconductor substrate as described in claim 12 or claim 13, wherein the developer used in the process of developing the exposed resist film is a basic liquid.

18. Before the step of applying the composition for forming a resist underlayer film, The method for producing a semiconductor substrate according to claim 12 or 13, further comprising the step of forming a silicon-containing film directly or indirectly on the substrate.

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