Semiconductor substrate manufacturing method, and resist base film forming composition

Abstract

The purpose of the present invention is to provide a manufacturing method of a semiconductor substrate that uses a resist underlayer film forming composition that can form a resist underlayer film with excellent pattern rectangularity, and to provide a resist underlayer film forming composition. This semiconductor substrate manufacturing method involves a step for coating a substrate directly or indirectly with a resist underlayer film forming composition, a step for coating the resist underlayer film, formed in the resist underlayer film forming composition coating step, with a resist film forming composition, a step for exposing the resist film formed in the resist film forming composition coating step with radiation, and a step for developing at least the exposed resist layer, wherein the resist underlayer film forming composition contains a polymer, an acid generator, and a solvent, and the thickness of the resist underlayer film is less than or equal to 6 nm.

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 there has been a trend toward shorter wavelength exposure light, 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 for such EUV exposure (see International Publication No. 2013 / 141015).

[0004] International Publication No. 2013 / 141015

[0005] As the line width of resist patterns formed by exposure to extreme ultraviolet light and development has become increasingly finer to the point of 20 nm or less, there is a demand for pattern rectangularity that suppresses pattern footing at the bottom of the resist film and ensures the 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 having excellent 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, the method 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 (hereinafter also referred to as "polymer [A]"), an acid generator (hereinafter also referred to as "acid generator [B]"), and a solvent (hereinafter also referred to as "solvent [C]"), and the film thickness of the resist underlayer film is 6 nm or less.

[0008] In another embodiment, the present invention relates to a composition for forming a resist underlayer film used to form a resist underlayer film having a film thickness of 6 nm or less, the composition comprising: a polymer; an acid generator; 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 pattern rectangularity is used, so that a semiconductor substrate can be produced efficiently. The composition for forming a resist underlayer film can form a film having excellent pattern rectangularity. Therefore, these compositions can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future.

[0010] 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 below. Combinations of preferred aspects in the embodiments are also preferred.

[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 with excellent pattern rectangularity can be formed, and therefore a semiconductor substrate with a good pattern shape can be produced.

[0013] 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).

[0014] Hereinafter, the composition for forming a resist underlayer film used in the method for producing a semiconductor substrate and each step in the case where the method includes the optional silicon-containing film-forming step will be described.

[0015] <Composition for forming a resist underlayer film> The composition for forming a resist underlayer film contains [A] a polymer, [B] an acid generator, and [C] a solvent. The composition may contain optional components as long as the effects of the present invention are not impaired. By containing [A] the polymer, [B] the acid generator, and [C] the solvent, the composition for forming a resist underlayer film can form a resist underlayer film that has excellent pattern rectangularity.

[0016] <Polymer (A)> The composition may contain one or more types of polymer (A).

[0017] The polymer (A) preferably has a repeating unit represented by the following formula (1) (hereinafter also referred to as “repeating unit (1)”). (In formula (1), R １ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. １ is a single bond or a divalent linking group.

[0018] 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).

[0019] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl; alkenyl groups such as ethenyl, propenyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0020] 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.

[0021] 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.

[0022] R １When 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, a nitro group, and a hydroxy group.

[0023] Among them, R １ In view of the copolymerizability of the monomer that gives the repeating unit (1), a hydrogen atom or a methyl group is preferred.

[0024] In the above formula (1), L １ The divalent linking group represented by the formula (I) is preferably a divalent hydrocarbon group, a carbonyl group, an oxygen atom (—O—), an imino group (—NH—), or a combination thereof.

[0025] L １ The divalent hydrocarbon group in R １ and groups in which one hydrogen atom has been removed from a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0026] Among them, L １ is preferably a single bond, an alkanediyl group obtained by removing one hydrogen atom from an alkyl group having 1 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, an imino group, or a combination thereof, and more preferably a single bond, an alkanediyl group having 1 to 5 carbon atoms, a phenylene group, a carbonyl group, an oxygen atom, an imino group, or a combination thereof.

[0027] Specific examples of the repeating unit (1) include repeating units represented by the following formulas (1-1) to (1-10).

[0028]

[0029] In the above formulas (1-1) to (1-10), R １has the same meaning as the above formula (1). Among these, the repeating units represented by the above formulas (1-1), (1-5) and (1-9) are preferred.

[0030] The lower limit of the content of the sulfonic acid group-containing repeating unit (1) in all repeating units constituting the polymer 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 40 mol%, and particularly preferably 30 mol%. By setting the content of the repeating unit (1) within the above range, a high level of pattern rectangularity can be achieved. Furthermore, by setting the content within the above range, when a basic liquid is used as a developer in the resist film development step, the resist underlayer film can also be removed together with the resist film.

[0031] The polymer (A) preferably has a repeating unit represented by the following formula (2) (hereinafter also referred to as “repeating unit (2)”). (In formula (2), R ２ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ２ is a single bond or a divalent linking group.

[0032] In the above formula (2), R ２ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １ 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. ２ From the viewpoint of copolymerizability of the monomer that gives the repeating unit (2), R is preferably a hydrogen atom or a methyl group. ２ When R has a substituent, the substituent may be R １ Suitable examples include the substituents that may be possessed by the following.

[0033] In the above formula (2), L ２ 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. ２is 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.

[0034] Specific examples of the repeating unit (2) include repeating units represented by the following formulas (2-1) to (2-8).

[0035]

[0036] In the above formulas (2-1) to (2-8), R ２ is synonymous with the above formula (2).

[0037] When the polymer [A] contains the repeating unit (2), the content of the repeating unit (2) in all repeating units constituting the polymer [A] is preferably 10 mol %, more preferably 15 mol %, and even more preferably 20 mol %. The upper limit of the content is preferably 99 mol %, more preferably 90 mol %, and even more preferably 80 mol %.

[0038] The polymer (A) preferably has a repeating unit represented by the following formula (3) (excluding the repeating unit (2) above) (hereinafter also referred to as “repeating unit (3)”): (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 substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0039] In the above formula (3), R ３ and R ４ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １The groups shown as substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by the following formula, can be preferably used. ３ From the viewpoint of copolymerizability of the monomer that gives the repeating unit (3), R is preferably a hydrogen atom or a methyl group. ４ 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. ３ and R ４ When R has a substituent, the substituent may be R １ Suitable examples include the substituents that may be possessed by the following.

[0040] In the above formula (3), L ３ 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. ３ 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.

[0041] Specific examples of the repeating unit (3) include repeating units represented by the following formulas (3-1) to (3-17).

[0042]

[0043] In the above formulas (3-1) to (3-17), R ３ is the same as the above formula (3).

[0044] When the polymer [A] contains the repeating unit (3), the content of the repeating unit (3) in all repeating units constituting the polymer [A] is preferably 10 mol %, more preferably 15 mol %, and even more preferably 20 mol %. The upper limit of the content is preferably 90 mol %, more preferably 85 mol %, and even more preferably 80 mol %.

[0045] It is preferable that the polymer (A) has a repeating unit represented by the following formula (4) (excluding the repeating unit (1), the repeating unit (2), and the repeating unit (3)) (hereinafter also referred to as “repeating unit (4)”): (In formula (4), R ５ is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. ４ is a single bond or a divalent linking group. １ is a monovalent group having an aromatic ring with 6 to 20 ring members.

[0046] 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.

[0047] In the above formula (4), R ５ The substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R １ 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. ５ From the viewpoint of copolymerizability of the monomer that gives the repeating unit (4), R is preferably a hydrogen atom or a methyl group. ５ When R has a substituent, the substituent may be R １ Suitable examples include the substituents that may be possessed by the following.

[0048] In the above formula (4), L ４ 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. ４ 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.

[0049] 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.

[0050] In the above formula (4), 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.

[0051] In the above formula (4), Ar １ The monovalent group having an aromatic ring with 6 to 20 ring members represented by the formula (1) may have a substituent. In this case, the substituent may be R １ The substituents exemplified above can be suitably employed when the group has a substituent. The substituent is preferably a hydroxy group.

[0052] Specific examples of the repeating unit (4) include repeating units represented by the following formulas (4-1) to (4-10).

[0053]

[0054] In the above formulas (4-1) to (4-10), R ５ has the same meaning as the above formula (4). Among these, the repeating units represented by the above formulas (4-1), (4-9) and (4-10) are preferred.

[0055] When the polymer [A] contains the repeating unit (4), the content of the repeating unit (4) in all repeating units constituting the polymer [A] is preferably 10 mol %, more preferably 20 mol %, and even more preferably 30 mol %. The upper limit of the content is preferably 95 mol %, more preferably 90 mol %, and even more preferably 80 mol %.

[0056] Examples of other repeating units include repeating units used in the polymer of the resist composition, such as repeating units incorporating the structure of the acid generator described below.

[0057] 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.

[0058] 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].

[0059] 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 1 mass %, more preferably 5 mass %, even more preferably 10 mass %, and particularly preferably 15 mass %, and the upper limit of the content is preferably 99 mass %, more preferably 95 mass %, and even more preferably 90 mass %.

[0060] [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.

[0061] 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), and dimethyl 2,2'-azobisisobutyrate; 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.

[0062] 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.

[0063] 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.

[0064] <[B] Acid Generator> The [B] acid generator is a component that generates an acid when acted upon by heat or light. The [B] acid generator may be used alone or in combination of two or more.

[0065] Examples of the acid generator (B) include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds.

[0066] Examples of the onium salt compound include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts.

[0067] Specific examples of the acid generator (B) include the compounds described in paragraphs

[0080] to

[0113] of JP-A No. 2009-134088.

[0068] The acid generator (B) is preferably an acid generator represented by the following formula (c): When the acid generator (B) has the following structure, it is believed that the diffusion length of the acid generated in the patterned exposure step in the resist underlayer film is suitably shortened, and as a result, a resist underlayer film with excellent pattern rectangularity can be formed.

[0069]

[0070] In the above formula (c), R ｐ１ R is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. ｐ２ is a divalent linking group. ｐ３ and R ｐ４ are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. ｐ５ and R ｐ６ are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. ｐ１ is an integer from 0 to 10. ｐ２ is an integer from 0 to 10. ｐ３ is an integer from 1 to 10. ｐ１ If there are two or more R ｐ２ are the same or different. ｐ２ If there are two or more R ｐ３ are the same or different, and multiple R ｐ４ are the same or different. ｐ３ If there are two or more R ｐ５ are the same or different, and multiple R ｐ６ are the same or different. ＋ is a monovalent radiation-sensitive onium cation.

[0071] R ｐ１Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (I) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group (a) containing a divalent heteroatom-containing group between carbon atoms of the hydrocarbon group or at the terminal on the bond side, a group in which some or all of the hydrogen atoms in the hydrocarbon group and group (a) have been substituted with a monovalent heteroatom-containing group, or a group formed by combining these groups.

[0072] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include R １ Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same groups as those exemplified above.

[0073] Examples of the divalent heteroatom-containing group include —O—, —CO—, —CO—O—, —S—, —CS—, and —SO ２ -, -NR'-, and a group formed by combining two or more of these groups, etc. R' is a hydrogen atom or a monovalent hydrocarbon group.

[0074] Examples of the monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group and sulfanyl group (-SH).

[0075] R ｐ１ It is preferable that the ring structure contains a ring structure having 6 or more ring members. Examples of the ring structure include an alicyclic structure, an aliphatic heterocyclic structure, an aromatic ring structure, and an aromatic heterocyclic structure, each of which has 6 or more ring members.

[0076] Examples of the alicyclic structure having 6 or more ring members include monocyclic cycloalkane structures such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure; monocyclic cycloalkene structures such as a cyclohexene structure, a cycloheptene structure, a cyclooctene structure, and a cyclodecene structure; polycyclic cycloalkane structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure; and polycyclic cycloalkene structures such as a norbornene structure and a tricyclodecene structure.

[0077] Examples of the aliphatic heterocyclic structure having 6 or more ring members include lactone structures such as a hexanolactone structure and a norbornanelactone structure; sultone structures such as a hexanosultone structure and a norbornanesultone structure; oxygen atom-containing heterocyclic structures such as an oxacycloheptane structure and an oxanorbornane structure; nitrogen atom-containing heterocyclic structures such as an azacyclohexane structure and a diazabicyclooctane structure; and sulfur atom-containing heterocyclic structures such as a thiacyclohexane structure and a thianorbornane structure.

[0078] Examples of the aromatic ring structure having six or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

[0079] Examples of the aromatic heterocyclic structure having 6 or more ring members include oxygen atom-containing heterocyclic structures such as a furan structure, a pyran structure, and a benzopyran structure, and nitrogen atom-containing heterocyclic structures such as a pyridine structure, a pyrimidine structure, and an indole structure.

[0080] R ｐ１ The lower limit of the number of ring members in the ring structure is preferably 7, more preferably 8, even more preferably 9, and particularly preferably 10. On the other hand, the upper limit of the number of ring members is preferably 15, more preferably 14, even more preferably 13, and particularly preferably 12. By setting the number of ring members within the above range, the diffusion length of the acid can be further suitably shortened, and as a result, various performance properties of the chemically amplified resist material can be further improved.

[0081] R ｐ１ Some or all of the hydrogen atoms in the ring structure may be substituted with a substituent. １ The substituents mentioned above when the group has a substituent can be suitably used. Among these, a hydroxy group is preferred.

[0082] R ｐ１Among these, preferred are monovalent groups containing an alicyclic structure having 6 or more ring members and monovalent groups containing an aliphatic heterocyclic structure having 6 or more ring members, more preferred are monovalent groups containing an alicyclic structure having 9 or more ring members and monovalent groups containing an aliphatic heterocyclic structure having 9 or more ring members, and particularly preferred are adamantyl group, hydroxyadamantyl group, norbornane lactone-yl group, norbornane sultone-yl group and 5-oxo-4-oxatricyclo[4.3.1.1 ３，８ ]undecanyl is more preferred, and adamantyl is especially preferred.

[0083] R ｐ２ Examples of the divalent linking group represented by R include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, a divalent hydrocarbon group, or a combination thereof. ｐ２ The divalent linking group represented by the formula (I) is preferably a carbonyloxy group, a sulfonyl group, an alkanediyl group, or a cycloalkanediyl group, more preferably a carbonyloxy group or a cycloalkanediyl group, still more preferably a carbonyloxy group or a norbornanediyl group, and particularly preferably a carbonyloxy group.

[0084] R ｐ３ and R ｐ４ Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R include an alkyl group having 1 to 20 carbon atoms. ｐ３ and R ｐ４ Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (R) include a fluorinated alkyl group having 1 to 20 carbon atoms. ｐ３ and R ｐ４ As the alkyl group, a hydrogen atom, a fluorine atom and a fluorinated alkyl group are preferred, a fluorine atom and a perfluoroalkyl group are more preferred, and a fluorine atom and a trifluoromethyl group are even more preferred.

[0085] R ｐ５ and R ｐ６ Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (R) include a fluorinated alkyl group having 1 to 20 carbon atoms. ｐ５ and R ｐ６As the alkyl group, a fluorine atom and a fluorinated alkyl group are preferred, a fluorine atom and a perfluoroalkyl group are more preferred, a fluorine atom and a trifluoromethyl group are further preferred, and a fluorine atom is particularly preferred.

[0086] n ｐ１ is preferably an integer of 0 to 5, more preferably an integer of 0 to 3, still more preferably an integer of 0 to 2, and particularly preferably 0 or 1.

[0087] n ｐ２ is preferably an integer of 0 to 5, more preferably an integer of 0 to 2, further preferably 0 or 1, and particularly preferably 0.

[0088] n ｐ３ is preferably an integer of 1 to 5, more preferably an integer of 1 to 4, even more preferably an integer of 1 to 3, and particularly preferably 1 or 2.

[0089] X ＋ The monovalent radiation-sensitive onium cation represented by the formula (I) is a cation that decomposes upon irradiation with exposure light. In the exposed area, sulfonic acid is produced from a proton generated by decomposition of this photodecomposable onium cation and a sulfonate anion. ＋ Examples of the monovalent radiation-sensitive onium cation represented by the formula (c-a) below (hereinafter also referred to as "cation (c-a)"), the cation represented by the formula (c-b) below (hereinafter also referred to as "cation (c-b)"), and the cation represented by the formula (c-c) below (hereinafter also referred to as "cation (c-c)").

[0090]

[0091] In the above formula (ca), R Ｃ３ , R Ｃ４ and R Ｃ５ each independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, -OSO ２ -R ＣＣ１ or -SO ２ -R ＣＣ２or a ring structure formed by combining two or more of these groups together. ＣＣ１ and R ＣＣ２ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. c1, c2, and c3 are each independently an integer of 0 to 5. R Ｃ３ ~R Ｃ５ and R ＣＣ１ and R ＣＣ２ If there are multiple R Ｃ３ ~R Ｃ５ and R ＣＣ１ and R ＣＣ２ may be the same or different.

[0092] In the above formula (c-b), R Ｃ６ is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. c4 is an integer of 0 to 7. R Ｃ６ If there are multiple R Ｃ６ may be the same or different, and multiple R Ｃ６ may represent a ring structure formed by combining with each other. Ｃ７ is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. c5 is an integer of 0 to 6. R Ｃ７ If there are multiple R Ｃ７ may be the same or different, and multiple R Ｃ７ may represent a ring structure formed by combining with each other. ｃ２ is an integer from 0 to 3. Ｃ８ is a single bond or a divalent organic group having 1 to 20 carbon atoms. ｃ１ is an integer from 0 to 2.

[0093] In the above formula (cc), R Ｃ９ and R Ｃ１０each independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, -OSO ２ -R ＣＣ３ or -SO ２ -R ＣＣ４ or a ring structure formed by combining two or more of these groups together. ＣＣ３ and R ＣＣ４ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. c6 and c7 are each independently an integer of 0 to 5. R Ｃ９ , R Ｃ１０ , R ＣＣ３ and R ＣＣ４ If there are multiple R Ｃ９ , R Ｃ１０ , R ＣＣ３ and R ＣＣ４ may be the same or different.

[0094] R Ｃ３ , R Ｃ４ , R Ｃ５ , R Ｃ６ , R Ｃ７ , R Ｃ９ and R Ｃ１０ Examples of the unsubstituted linear alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.

[0095] R Ｃ３ , R Ｃ４ , R Ｃ５ , R Ｃ６ , R Ｃ７ , R Ｃ９ and R Ｃ１０ Examples of the unsubstituted branched alkyl group represented by the formula (I) include an isopropyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.

[0096] R Ｃ３ , R Ｃ４ , R Ｃ５ , R Ｃ９ and R Ｃ１０Examples of the unsubstituted aromatic hydrocarbon group represented by the formula include aryl groups such as phenyl, tolyl, xylyl, mesityl and naphthyl; and aralkyl groups such as benzyl and phenethyl.

[0097] R Ｃ６ and R Ｃ７ Examples of the unsubstituted aromatic hydrocarbon group represented by the formula (I) include a phenyl group, a tolyl group, and a benzyl group.

[0098] R Ｃ８ The divalent organic group represented by R ｐ１ A group in which one hydrogen atom has been removed from a monovalent organic group having 1 to 20 carbon atoms, represented by the following formula:

[0099] The substituents which may substitute hydrogen atoms of the alkyl group and aromatic hydrocarbon group include R １ Among these, a halogen atom is preferred, and a fluorine atom is more preferred.

[0100] R Ｃ３ , R Ｃ４ , R Ｃ５ , R Ｃ６ , R Ｃ７ , R Ｃ９ and R Ｃ１０ Examples of the alkyl group include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, and —OSO ２ -R ＢＢ５ , and -SO ２ -R ＢＢ５ is preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is even more preferred. ＢＢ５ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

[0101] In formula (ca), c1, c2, and c3 are preferably integers of 0 to 2, more preferably 0 and 1, and even more preferably 0. In formula (cb), c4 is preferably an integer of 0 to 2, more preferably 0 and 1, and even more preferably 1. In formula (cb), c5 is preferably an integer of 0 to 2, more preferably 0 and 1, and even more preferably 0. n ｃ２ As n, 2 and 3 are preferred, and 2 is more preferred. ｃ１ is preferably 0 or 1, and more preferably 0. c6 and c7 in formula (cc) are preferably integers of 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0102] X ＋ Among these, the cation (ca) and the cation (cb) are preferred, and the diphenyliodonium cation, the triphenylsulfonium cation, the 1-[2-(4-cyclohexylphenylcarbonyl)propan-2-yl]tetrahydrothiophenium cation, and the 4-cyclohexylsulfonylphenyldiphenylsulfonium cation are more preferred.

[0103] Examples of the acid generator represented by formula (c) above include compounds represented by the following formulas (c1) to (c16) (hereinafter also referred to as "compounds (c1) to (c16)").

[0104]

[0105]

[0106] In the above formulas (c1) to (c16), X ＋ is a monovalent radiation-sensitive onium cation.

[0107] The acid generator (B) is preferably an onium salt compound, more preferably a sulfonium salt compound or an iodonium salt compound, and further preferably the compounds (c5), (c14), (c15), and (c16) and the compounds of the examples.

[0108] When the composition for forming a resist underlayer film contains the acid generator (B), the lower limit of the content of the acid generator (B) is preferably 0.1 parts by mass, more preferably 1 part by mass, and even more preferably 3 parts by mass, relative to 100 parts by mass of the polymer (A). The upper limit of the content is preferably 40 parts by mass, more preferably 30 parts by mass, and even more preferably 20 parts by mass.

[0109] <Solvent (C)> The solvent (C) is not particularly limited as long as it can dissolve or disperse the polymer (A) and the acid generator (B) and any optional components contained as needed.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, n-propanol, and 4-methyl-2-pentanol, and polyalcohol solvents such as ethylene glycol and 1,2-propylene glycol.

[0114] 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.

[0115] 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.

[0116] Examples of nitrogen-containing solvents include chain nitrogen-containing solvents such as N,N-dimethylacetamide, and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0117] 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, or a polyhydric alcohol partial ether carboxylate solvent, and still more preferably 4-methyl-2-pentanol, propylene glycol monomethyl ether, or propylene glycol monomethyl ether acetate.

[0118] 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.

[0119] [Optional Components] The composition for forming a resist underlayer film may contain optional components within the range that does not impair the effects of the present invention. Examples of optional components include a crosslinking agent, an acid diffusion controller, a surfactant, etc. The optional components can be used alone or in combination of two or more.

[0120] (Acid Diffusion Controller [E]) The acid diffusion controller [E] captures acids and cations. The acid diffusion controller [E] may be used alone or in combination of two or more.

[0121] The acid diffusion controller (E) can be divided into compounds having radiation reactivity and compounds having no radiation reactivity.

[0122] The radiation-nonreactive compound is preferably a basic compound, such as hydroxide compounds, carboxylate compounds, amine compounds, imine compounds, and amide compounds, more specifically, primary to tertiary aliphatic amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, nitrogen-containing compounds having a carbamate group, amide compounds, and imide compounds, and among these, nitrogen-containing compounds having a carbamate group are preferred.

[0123] The basic compound may also be a Troger's base; a hindered amine such as diazabicycloundecene (DBU) or diazabicyclononene (DBM); or an ionic quencher such as tetrabutylammonium hydroxide (TBAH) or tetrabutylammonium lactate.

[0124] Examples of the primary aliphatic amine include ammonia, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, pentylamine, tert-amylamine, cyclopentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, dodecylamine, cetylamine, methylenediamine, ethylenediamine, and tetraethylenepentamine.

[0125] Examples of the secondary aliphatic amine include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine, dicyclopentylamine, dihexylamine, dicyclohexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine, N,N-dimethylmethylenediamine, N,N-dimethylethylenediamine, and N,N-dimethyltetraethylenepentamine.

[0126] Examples of the tertiary aliphatic amine include trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine, tricyclopentylamine, trihexylamine, tricyclohexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, tridodecylamine, tricetylamine, N,N,N',N'-tetramethylmethylenediamine, N,N,N',N'-tetramethylethylenediamine, and N,N,N',N'-tetramethyltetraethylenepentamine.

[0127] Examples of the aromatic amines and heterocyclic amines include aniline derivatives such as aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline, propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, and N,N-dimethyltoluidine; diphenyl(p-tolyl)amine; methyldiphenylamine; diaminonaphthalene; pyrrole derivatives such as pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, and N-methylpyrrole; oxazole derivatives such as oxazole and isoxazole; thiazole derivatives such as thiazole and isothiazole; imidazole derivatives such as imidazole, 4-methylimidazole, and 4-methyl-2-phenylimidazole; pyrazole derivatives; furazan derivatives; pyrroline derivatives such as pyrroline and 2-methyl-1-pyrroline Conductors; pyrrolidine derivatives such as pyrrolidine, N-methylpyrrolidine, pyrrolidinone, and N-methylpyrrolidone; imidazoline derivatives; imidazolidine derivatives; pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 4-pyrrolidine pyridine derivatives such as 2-(1-ethylpropyl)pyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine; pyridazine derivatives; pyrimidine derivatives; pyrazine derivatives; pyrazoline derivatives; pyrazolidine derivatives; piperidine derivatives; piperazine derivatives; morpholine derivatives; indole derivatives; isoindole derivatives; 1H-indazole derivatives; indoline derivatives; quinoline derivatives such as quinoline and 3-quinolinecarbonitrile; isoquinoline derivatives; cinnoline derivatives; quinazoline derivatives; quinoxaline derivatives; phthalazine derivatives; purine derivatives;Examples include pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine derivatives, guanine derivatives, guanosine derivatives, uracil derivatives, and uridine derivatives.

[0128] Examples of the nitrogen-containing compound having a carboxy group include aminobenzoic acid; indolecarboxylic acid; and amino acid derivatives such as nicotinic acid, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine, phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic acid, and methoxyalanine.

[0129] Examples of the nitrogen-containing compound having a sulfonyl group include 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate.

[0130] Examples of the nitrogen-containing compound having a hydroxy group, the nitrogen-containing compound having a hydroxyphenyl group, and the alcoholic nitrogen-containing compound include 2-hydroxypyridine, aminocresol, 2,4-quinolinediol, 3-indole methanol hydrate, monoethanolamine, diethanolamine, triethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine, triisopropanolamine, 2,2'-iminodiethanol, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine, 2 ... Examples of such compounds include 1-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine, 1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidineethanol, 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone, 3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyyulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidineethanol, 1-aziridineethanol, N-(2-hydroxyethyl)phthalimide, and N-(2-hydroxyethyl)isonicotinamide.

[0131] Examples of nitrogen-containing compounds having a carbamate group include N-(tert-butoxycarbonyl)-L-alanine, N-(tert-butoxycarbonyl)-L-alanine methyl ester, (S)-(-)-2-(tert-butoxycarbonylamino)-3-cyclohexyl-1-propanol, (R)-(+)-2-(tert-butoxycarbonylamino)-3-methyl-1-butanol, (R)-(+)-2-(tert-butoxycarbonylamino)-3-phenylpropanol, (S)-(-)-2-(tert-butoxycarbonylamino)-3-phenylpropanol, N-(tert-butoxycarbonyl)-L-aspartic acid 4-benzyl ester, ... N-(tert-butoxycarbonyl)-O-benzyl-L-threonine, (R)-(+)-1-(tert-butoxycarbonyl)-2-tert-butyl-3-methyl-4-imidazolidinone, (S)-(-)-1-(tert-butoxycarbonyl)-2-tert-butyl-3-methyl-4-imidazolidinone, N-(tert-butoxycarbonyl)-3-cyclohexyl-L-alanine methyl ester, N-(tert-butoxycarbonyl)-L-cysteine ​​methyl ester, N-(tert-butoxycarbonyl)ethanolamine, N-(tert-butoxycarbonyl)- N-(tert-butoxycarbonyl)-L-isoleucine, N-(tert-butoxycarbonyl)-L-isoleucine methyl ester, N-(tert-butoxycarbonyl)-L-leucinol, N-(tert-butoxycarbonyl)-L-lysine, N-(tert-butoxycarbonyl)-L-methinonine,N-(tert-butoxycarbonyl)-3-(2-naphthyl)-L-alanine, N-(tert-butoxycarbonyl)-L-phenylalanine, N-(tert-butoxycarbonyl)-L-phenylalanine methyl ester, N-(tert-butoxycarbonyl)-D-prolinal, N-(tert-butoxycarbonyl)-L-proline, N-(tert-butoxycarbonyl)-L-proline-N'-methoxy-N'-methylamide, N-(tert-butoxycarbonyl)-1H-pyrazole-1-carboxyamidine, (S )-(-)-1-(tert-butoxycarbonyl)-2-pyrrolidinemethanol, (R)-(+)-1-(tert-butoxycarbonyl)-2-pyrrolidinemethanol, 1-(tert-butoxycarbonyl)3-[4-(1-pyrrolyl)phenyl]-L-alanine, N-(tert-butoxycarbonyl)-L-serine, N-(tert-butoxycarbonyl)-L-serine methyl ester, N-(tert-butoxycarbonyl)-L-threonine, N-(tert-butoxycarbonyl)-p-toluenesulfonamide, N-(t N-(tert-butoxycarbonyl)-S-trityl-L-cysteine, Nα-(tert-butoxycarbonyl)-L-tryptophan, N-(tert-butoxycarbonyl)-L-tyrosine, N-(tert-butoxycarbonyl)-L-tyrosine methyl ester, N-(tert-butoxycarbonyl)-L-valine, N-(tert-butoxycarbonyl)-L-valine methyl ester, N-(tert-butoxycarbonyl)-L-valinol, tert-butyl N-(3-hydroxypropyl)carbamate, tert-butyl N- (6-aminohexyl)carbamate, tert-butyl carbamate, tert-butyl carbazate, tert-butyl-N-(benzyloxy)carbamate, tert-butyl-4-benzyl-1-piperazinecarboxylate, tert-butyl (1S,4S)-(-)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate, tert-butyl-N-(2,3-dihydroxypropyl)carbamate, tert-butyl (S)-(-)-4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate,Examples include tert-butyl [R-(R*, S*)]-N-[2-hydroxy-2-(3-hydroxyphenyl)-1-methylethyl]carbamate, tert-butyl-4-oxo-1-piperidinecarboxylate, tert-butyl-1-pyrrolecarboxylate, tert-butyl-1-pyrrolidinecarboxylate, and tert-butyl(tetrahydro-2-oxo-3-furanyl)carbamate.

[0132] Examples of the amide compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, and 1-cyclohexylpyrrolidone.

[0133] Examples of the imide compound include phthalimide, succinimide, and maleimide.

[0134] The radiation-reactive compounds are divided into compounds that are decomposed by radiation and lose their acid diffusion control ability (radiation-decomposing compounds) and compounds that are generated by radiation and gain acid diffusion control ability (radiation-generating compounds).

[0135] The radiation decomposable compound is preferably a sulfonate or carboxylate of a radiation decomposable cation. The sulfonic acid in the sulfonate is preferably a weak acid, more preferably one having a hydrocarbon group of 1 to 20 carbon atoms, wherein the hydrocarbon group does not contain fluorine. Examples of such sulfonic acids include alkylsulfonic acid, benzenesulfonic acid, and 10-camphorsulfonic acid. The carboxylic acid in the carboxylate is preferably a weak acid, more preferably a carboxylic acid having 1 to 20 carbon atoms. Examples of such carboxylic acids include formic acid, acetic acid, propionic acid, tartaric acid, succinic acid, cyclohexylcarboxylic acid, benzoic acid, and salicylic acid. The radiation decomposable cation in the carboxylate of a radiation decomposable cation is preferably an onium cation, and examples of such onium cations include an iodonium cation and a sulfonium cation.

[0136] The radiation-generating compound is preferably a compound that generates a base upon exposure (radiation-sensitive base generator), and more preferably a nitrogen-containing organic compound that generates an amino group.

[0137] Examples of the radiation-sensitive base generator include compounds described in JP-A Nos. 4-151156, 4-162040, 5-197148, 5-5995, 6-194834, 8-146608, and 10-83079, and European Patent No. 622682.

[0138] Examples of the radiation-sensitive base generator include compounds containing a carbamate group (urethane bond), compounds containing an acyloxyimino group, ionic compounds (anion-cation complexes), and compounds containing a carbamoyloxyimino group, with compounds containing a carbamate group (urethane bond), compounds containing an acyloxyimino group, and ionic compounds (anion-cation complexes) being preferred.

[0139] Furthermore, the radiation-sensitive base generator is preferably a compound having a ring structure in the molecule, such as benzene, naphthalene, anthracene, xanthone, thioxanthone, anthraquinone, or fluorene.

[0140] Examples of the radiation-sensitive base generator include 2-nitrobenzyl carbamate, 2,5-dinitrobenzyl cyclohexyl carbamate, N-cyclohexyl-4-methylphenylsulfonamide, and 1,1-dimethyl-2-phenylethyl-N-isopropyl carbamate.

[0141] When the composition for forming a resist underlayer film contains the acid diffusion controller (E), the lower limit of the content of the acid diffusion controller is preferably 0.1 parts by mass, more preferably 1 part by mass, and even more preferably 3 parts by mass, relative to 100 parts by mass of the polymer (A).The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, and even more preferably 30 parts by mass.

[0142] [Method for preparing a composition for forming a resist underlayer film] The composition for forming a resist underlayer film can be prepared by mixing [A] the polymer, [B] the acid generator, [C] the solvent, 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.

[0143] [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.

[0144] 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.

[0145] 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).

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] [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 [C].

[0151] When the composition for forming a resist underlayer film is applied directly to the substrate, the silicon-containing film forming step may be omitted.

[0152] Next, the coating film formed by the above coating is heated. Heating the coating film promotes the formation of the resist underlayer film. More specifically, heating the coating film promotes the volatilization of the solvent (C).

[0153] The coating film may be heated in an air atmosphere or a nitrogen atmosphere. The lower limit of the heating temperature is preferably 100°C, more preferably 150°C, and still more preferably 200°C. The upper limit of the heating temperature is preferably 400°C, more preferably 350°C, and still more preferably 280°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the heating time is preferably 1,200 seconds, and more preferably 600 seconds.

[0154] The lower limit of the film thickness (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 6 nm, preferably 5.5 nm, more preferably 5 nm, even more preferably 4.5 nm, and particularly preferably 4 nm. The method for measuring the average thickness is as described in the Examples.

[0155] [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.

[0156] 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.

[0157] 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.

[0158] Examples of the resist film-forming composition used in this step include positive or negative chemically amplified resist compositions that contain a radiation-sensitive acid generator, positive resist compositions that contain an alkali-soluble resin and a quinone diazide-based photosensitizer, negative resist compositions that contain an alkali-soluble resin and a crosslinking agent, and metal-containing resist compositions that contain a metal such as tin or zirconium.

[0159] [Exposure Step] In this step, the resist film formed in the resist film-forming composition application step is exposed to radiation.

[0160] 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 ２ Excimer 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.

[0161] 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.

[0162] [Development Step] In this step, the exposed resist film is developed. At this time, a part of the resist underlayer film may also be developed. Examples of the developer used in this development include an alkaline aqueous solution (alkaline developer), a liquid containing an organic solvent (organic solvent developer), etc.

[0163] 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.

[0164] Examples of organic solvent developers for use in organic solvent development include those exemplified above as the solvent [C]. Preferred organic solvent developers are ester-based solvents, ether-based solvents, alcohol-based solvents, ketone-based solvents, and / or hydrocarbon-based solvents, more preferably ketone-based solvents, and particularly preferably 2-heptanone.

[0165] In this step, washing and / or drying may be carried out after the development.

[0166] [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.

[0167] 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, N ２ 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.

[0168] After the substrate pattern is formed, if the silicon-containing film remains on the substrate, the silicon-containing film can be removed by carrying out the removal step described below.

[0169] The resist underlayer film-forming composition contains a polymer (A), an acid generator (B), and a solvent (C). The resist underlayer film-forming composition may be suitably the same as the resist underlayer film-forming composition used in the method for producing a semiconductor substrate.

[0170] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0171] [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.

[0172] [Film Thickness (Average Thickness) of Resist Underlayer Film] The film thickness (average thickness) of the resist underlayer film was determined by measuring the film thickness at arbitrary 9 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 value of the film thicknesses.

[0173] <Synthesis of Polymer [A]> Polymers represented by the following formulae (A-1) and (A-2) (hereinafter also referred to as "polymers (A-1) and (A-2)") were synthesized according to the procedure described below.

[0174]

[0175] Synthesis Example 1-1 (Synthesis of Polymer (A-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 (A-1). The Mw of polymer (A-1) was 6,500.

[0176] Synthesis Example 1-2 (Synthesis of Polymer (A-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 (A-2). The Mw of polymer (A-2) was 5,300.

[0177] <Preparation of composition for forming resist underlayer film> [A] polymer, [B] acid generator, [C] solvent, [D] crosslinking agent, and [E] acid diffusion controller used in the preparation of the composition for forming resist underlayer film are shown below.

[0178] [[A] Polymer] The polymers (A-1) and (A-2) synthesized above and the following polymer (A-3) (Mw: 8,900)

[0179] In the above formulas (A-1) to (A-3), the number attached to each structural unit indicates the content (mol %) of that structural unit.

[0180] [[B] Acid Generator] Compounds represented by the following formulae (B-1) to (B-49):

[0181]

[0182]

[0183]

[0184]

[0185] [[C] Solvent] C-1: Propylene glycol monomethyl ether acetate C-2: Propylene glycol monomethyl ether

[0186] [[D] Crosslinking Agent] D-1: A compound represented by the following formula (D-1):

[0187]

[0188] [[E] Acid Diffusion Controller] Compounds represented by the following formulae (E-1) to (E-9):

[0189] [Example 1-1] [A] 50 parts by mass of (A-1) as a polymer, 50 parts by mass of (A-2), [B] 10 parts by mass of (B-1) as an acid generator, [C] 1,100 parts by mass of (C-1) as a solvent, and 200 parts by mass of (C-2) (including propylene glycol monomethyl ether contained in the propylene glycol monomethyl ether solution of polymer (A-1)) were dissolved. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter having a pore size of 0.45 μm to prepare a composition for forming a resist underlayer film (J-1).

[0190] Examples 1-2 to 1-81 and Comparative Example 1-1 Compositions for forming resist underlayer films (J-2) to (J-81) and (CJ-1) were prepared in the same manner as in Example 1, except that the types and amounts of each component were used as shown in Tables 1 and 2 below. A "-" in the "B" column in Table 1 and a "-" in the "E" column in Table 2 indicate that the corresponding component was not used.

[0191]

[0192]

[0193] <Evaluation> Using the resist underlayer film-forming compositions prepared above, the rectangularity of the resist patterns was evaluated by the following method. The evaluation results are shown in Tables 3 and 4 below.

[0194] <Preparation of EUV exposure resist composition (R-1)> The resist composition (R-1) for EUV exposure 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.

[0195] [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 resist underlayer film-forming composition prepared above was applied to the silicon-containing film formed above, heated at 250 ° 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. A resist composition (R-1) for EUV exposure 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. Next, the resist film was irradiated with extreme ultraviolet rays using an EUV scanner (ASML's "TWINSCAN NXE:3300B" (NA 0.3, sigma 0.9, quadrupole illumination, 1:1 line and space mask with a line width on the wafer of 16 nm). After irradiation with extreme ultraviolet rays, 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), 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 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.

[0196]

[0197]

[0198] <Evaluation> Using the resist underlayer film-forming compositions prepared above, the rectangularity of the resist patterns was evaluated by the following method. The evaluation results are shown in Tables 5 and 6 below.

[0199] <Preparation of EUV exposure resist composition (R-2)>

[0200] [Synthesis of Compound] Compound (S-1) used in preparing EUV exposure resist composition (R-2) was synthesized by the following procedure. 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 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).

[0201] 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).

[0202] [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.

[0203]

[0204]

[0205] As can be seen from the results in Tables 3 to 6, the resist underlayer films formed from the compositions for forming resist underlayer films of the Examples were superior in pattern rectangularity compared to the resist underlayer films formed from the compositions for forming resist underlayer films of the Comparative Examples.

[0206] 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 pattern rectangularity is used, thereby enabling efficient production of a semiconductor substrate. The composition for forming a resist underlayer film of the present invention enables the formation of a film having excellent pattern rectangularity. Therefore, these compositions can be suitably used in the production of semiconductor devices, which are expected to become even more miniaturized in the future.

Claims

1. A composition for forming a resist underlayer film used to form a resist underlayer film having a film thickness of 6 nm or less, A polymer, an acid generator; Solvent and A composition for forming a resist underlayer film, comprising:

2. A composition for forming a resist underlayer film as described in claim 1, wherein the acid generator is an acid generator represented by the following formula (c): 【Chemical 1】 (In formula (c), R p1 represents a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. R p2 represents a divalent linking group. R p3 and R p4 each independently represent a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R p5 and R p6 each independently represent a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n p1 represents an integer of 0 to 10. n p2 represents an integer of 0 to 10. n p3 represents an integer of 1 to 10. When n p1 is 2 or greater, multiple R p2 s are the same or different. When n p2 is 2 or more, multiple R p3 are the same or different, and multiple R p4 are the same or different. When n p3 is 2 or more, multiple R p5 are the same or different, and multiple R p6 are the same or different. X + is a monovalent radiation-sensitive onium cation.

3. A composition for forming a resist underlayer film as described in claim 1, wherein the polymer has a repeating unit represented by the following formula (4): 【Chemistry 2】 (In formula (4), R 5 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. L 4 is a single bond or a divalent linking group. Ar 1 is a monovalent group having an aromatic ring having 6 to 20 ring members.)

4. 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, an acid generator; Solvent and Contains The method for producing a semiconductor substrate, wherein the resist underlayer film has a film thickness of 6 nm or less.

5. 5. The method for manufacturing a semiconductor substrate according to claim 4, wherein the radiation is extreme ultraviolet radiation.

6. 5. The method for producing a semiconductor substrate according to claim 4, wherein the developer used in the step of developing the exposed resist film is a basic liquid.

7. 7. The method for producing a semiconductor substrate according to claim 4, wherein the acid generator is an acid generator represented by the following formula (c): 【Chemistry 3】 (In formula (c), R ｐ１ R is a hydrogen atom, a fluorine atom, or a monovalent organic group having 1 to 20 carbon atoms. ｐ２ is a divalent linking group. ｐ３ and R ｐ４ are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. ｐ５ and R ｐ６ are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. ｐ１ is an integer from 0 to 10. ｐ２ is an integer from 0 to 10. ｐ３ is an integer from 1 to 10. ｐ１ If there are two or more R ｐ２ are the same or different. ｐ２ If there are two or more R ｐ３ are the same or different, and multiple R ｐ４ are the same or different. ｐ３ If there are two or more R ｐ５ are the same or different, and multiple R ｐ６ are the same or different. ＋ is a monovalent radiation-sensitive onium cation.

8. Before the step of applying the composition for forming a resist underlayer film, The method for producing a semiconductor substrate according to any one of claims 4 to 6, further comprising the step of forming a silicon-containing film directly or indirectly on the substrate.

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