Production method for semiconductor substrate and composition for resist underlayer formation

Abstract

The present invention provides: a production method for a semiconductor substrate that makes it possible to form a resist underlayer having excellent pattern rectangularity; and a composition for resist underlayer formation. Provided is a production method for a semiconductor substrate, said method comprising: a step for applying a composition for resist underlayer formation directly or indirectly onto a substrate; a step for applying a composition resist film formation directly or indirectly onto a resist underlayer formed in the step for applying the composition for resist underlayer formation; a step for exposing a resist film formed in the step for applying the composition resist film formation; and a step for developing at least the exposed resist film. The composition for resist underlayer formation contains a compound and a solvent. The compound comprises -ORA, where RA is a hydrogen atom, a C1-10 monovalent heteroatom-containing group, or a C1-10 monovalent organic group (excluding C1-10 monovalent heteroatom-containing groups). Among the structures constituting RA, when the proportion of hydrogen atoms is represented as x, the proportion of the C1-10 monovalent heteroatom-containing group is represented as y, and the proportion of the C1-10 monovalent organic group is represented as z, in the entirety of the compound, x+y+z=100, and the relations 20≤x≤95 and 5≤y≤80 are satisfied. The compound is a polymer which has a repeating unit represented by formula (1), an aromatic-ring-containing compound which has a molecular weight of 750-3,000 and which comprises -ORA, or a combination of these. (In formula (1), Ar1 is a divalent group having a 5- to 40-membered aromatic ring. R0 is a hydrogen atom or a C1-40 monovalent organic group. R1 is a C1-40 monovalent organic group. At least one selected from the group consisting of Ar1, R0, and R1 has -ORA.)

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 method for producing 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, the integration of semiconductor devices has become increasingly advanced, 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 (13.5 nm, hereinafter also referred to as "EUV"). Various studies have been conducted on compositions for forming resist underlayer films in such EUV exposure (see International Publication No. 2021 / 157551).

[0004] International Publication No. 2021 / 157551

[0005] A composition for forming a resist underlayer film is required to have a pattern rectangularity that prevents the pattern from trailing 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, which is capable of forming a resist underlayer film with excellent pattern rectangularity, and a composition for forming a resist underlayer film.

[0007] In one embodiment, the present invention includes the steps of: applying a composition for forming a resist underlayer film directly or indirectly to a substrate; applying a composition for forming a resist film directly or indirectly to a resist underlayer film formed in the step of applying a composition for forming a resist film; exposing the resist film formed in the step of applying a composition for forming a resist film; and developing at least the exposed resist film, wherein the composition for forming a resist underlayer film includes a compound (hereinafter also referred to as "compound [A]") and a solvent (hereinafter also referred to as "solvent [B]"), and the compound is an -OR Ａ and R Ａ is either a hydrogen atom, a monovalent heteroatom-containing group having 1 to 10 carbon atoms, or a monovalent organic group having 1 to 10 carbon atoms (excluding monovalent heteroatom-containing groups having 1 to 10 carbon atoms), and the R Ａ In the structure constituting the formula (I), the proportion of hydrogen atoms is x, the proportion of monovalent heteroatom-containing groups having 1 to 10 carbon atoms is y, and the proportion of monovalent organic groups having 1 to 10 carbon atoms is z, where x + y + z = 100 and the relationships of 20≦x≦95 and 5≦y≦80 are satisfied for the entire compound, and the compound is a polymer having a repeating unit represented by the following formula (1) (hereinafter also referred to as “polymer [A1]”), a molecular weight of which is 750 or more and 3000 or less, and Ａ The present invention relates to a method for manufacturing a semiconductor substrate, wherein the aromatic ring-containing compound (hereinafter also referred to as "aromatic ring-containing compound (A2)") has the formula: (In formula (1), Ar １ is a divalent group having an aromatic ring with 5 to 40 ring members. ０ is a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. １ is a monovalent organic group having 1 to 40 carbon atoms. １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ )

[0008] In another embodiment, the present invention includes a compound, and a solvent, wherein the compound is -OR Ａ and R Ａis either a hydrogen atom, a monovalent heteroatom-containing group having 1 to 10 carbon atoms, or a monovalent organic group having 1 to 10 carbon atoms (excluding monovalent heteroatom-containing groups having 1 to 10 carbon atoms), and the R Ａ In the structure constituting the formula (1), the proportion of hydrogen atoms is x, the proportion of monovalent heteroatom-containing groups having 1 to 10 carbon atoms is y, and the proportion of monovalent organic groups having 1 to 10 carbon atoms is z, and the compound as a whole satisfies the relationships of x + y + z = 100, 20 ≦ x ≦ 95, and 5 ≦ y ≦ 80, and the compound is a polymer having a repeating unit represented by the following formula (1), a molecular weight of which is 750 or more and 3000 or less, and -OR Ａ or a combination thereof. (In formula (1), Ar １ is a divalent group having an aromatic ring with 5 to 40 ring members. ０ is a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. １ is a monovalent organic group having 1 to 40 carbon atoms. １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ )

[0009] According to this method for producing a semiconductor substrate, a resist underlayer film having excellent pattern rectangularity is formed, thereby enabling a well-patterned semiconductor substrate to be obtained. According to this composition for forming a resist underlayer film, a resist underlayer film having excellent pattern rectangularity can be formed. Furthermore, according to this method for producing a semiconductor substrate, a resist underlayer film having excellent embedding properties that allow the substrate pattern to be sufficiently embedded, as well as excellent flatness of the film after embedding, can be formed. According to this composition for forming a resist underlayer film, a resist underlayer film having excellent embedding properties and flatness can be formed. 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] FIG. 1 is a schematic cross-sectional view of a silicon substrate with a resist underlayer film for explaining a method for evaluating flatness.

[0011] 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. In the embodiments, a combination of preferred aspects is also preferred.

[0012] <<Method for manufacturing semiconductor substrate>> The method for manufacturing a semiconductor substrate includes a step of directly or indirectly applying a composition for forming a resist underlayer film to a substrate (hereinafter also referred to as a “coating step (I)”), a step of directly or indirectly 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 extreme ultraviolet light (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”).

[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] First, the composition for forming a resist underlayer film used in the method for producing a semiconductor substrate will be described, followed by a description of each step in the optional silicon-containing film formation step.

[0015] <<Composition for forming a resist underlayer film>> The composition for forming a resist underlayer film (hereinafter also simply referred to as the “composition”) contains a compound (A) and a solvent (B). The composition may contain optional components as long as the optional components do not impair the effects of the present invention.

[0016] Each component contained in the composition will be described below.

[0017] <Compound [A]> Compound [A] is a compound having —OR Ａ The compound [A] is a polymer [A1], an aromatic ring-containing compound [A2] (excluding compounds corresponding to the polymer [A1]), or a combination thereof. Ａ and the aromatic ring-containing compound [A2] may have —OR Ａand both the polymer [A1] and the aromatic ring-containing compound [A2] may have —OR Ａ The polymer [A1] and the aromatic ring-containing compound [A2] may each be used alone or in combination of two or more. Ａ The details will be described in the sections on the polymer [A1] and the aromatic ring-containing compound [A2].

[0018] (Polymer [A1]) The polymer [A1] as the compound [A] is a polymer having a repeating unit represented by the following formula (1): The polymer [A1] may have two or more types of repeating units represented by the following formula (1). (In formula (1), Ar １ is a divalent group having an aromatic ring with 5 to 40 ring members. ０ is a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. １ is a monovalent organic group having 1 to 40 carbon atoms. １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ )

[0019] In the above formula (1), Ar １ Examples of the aromatic ring having 5 to 40 ring members in the formula (I) include aromatic hydrocarbon rings such as 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, heteroaromatic rings such as a furan ring, a pyrrole ring, a thiophene ring, a phosphole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring, or combinations thereof. 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, and a perylene ring.

[0020] 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 ring members, a naphthalene ring has 10 ring members, and a fluorene ring has 13 ring members. The term "polycyclic fused aromatic ring" refers to a polycyclic aromatic hydrocarbon in which multiple aromatic rings share a side (a bond between two adjacent atoms).

[0021] In the above formula (1), Ar １ As the divalent group having an aromatic ring with 5 to 40 ring members represented by the formula １ Suitable examples include a group in which two hydrogen atoms have been removed from an aromatic ring having 5 to 40 ring members or a combination of the aromatic ring and a chain structure in the formula (I) above. When aromatic rings are combined, the aromatic rings may be bonded to each other via a single bond as well as a fused ring structure.

[0022] As the chain structure, a group in which two hydrogen atoms have been removed from a chain hydrocarbon having 1 to 20 carbon atoms can be suitably used. Examples of chain hydrocarbons having 1 to 20 carbon atoms include alkanes having 1 to 20 carbon atoms, such as methane, ethane, propane, butane, hexane, and octane. These may be either linear or branched. Of these, linear or branched alkanes having 1 to 8 carbon atoms are preferred.

[0023] In the above formula (1), R ０ and R １ Examples of the monovalent organic group having 1 to 40 carbon atoms represented by the formula (I) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group having a divalent heteroatom-containing linking group between carbon atoms of the hydrocarbon group or at the carbon chain terminal, a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with a monovalent heteroatom-containing substituent, and a combination thereof.

[0024] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and combinations thereof.

[0025] 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, and tert-butyl; alkenyl groups such as ethenyl, propenyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0026] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, 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.

[0027] 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.

[0028] Examples of heteroatoms constituting the divalent heteroatom-containing linking group or monovalent heteroatom-containing substituent 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.

[0029] Examples of the divalent heteroatom-containing linking group include -CO-, -CS-, -NH-, -O-, -S-, -SO-, and -SO ２ -, or a group in which these are combined.

[0030] Examples of the monovalent heteroatom-containing substituent include a hydroxy group, a sulfanyl group, a cyano group, a nitro group, and a halogen atom.

[0031] The above R ０ is preferably a hydrogen atom.

[0032] The above R １ Preferably, R has an aromatic ring having 5 to 40 ring members. １ The aromatic ring having 5 to 40 ring members in the above Ar１ An aromatic ring having 5 to 40 ring members can be suitably used.

[0033] In the above formula (1), Ar １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ Ar １ and R １ At least one of the following is -OR Ａ It is preferable that the group has the formula: Ａ is Ar １ , R ０ and R １ R Ａ is either a hydrogen atom, a monovalent heteroatom-containing group having 1 to 10 carbon atoms, or a monovalent organic group having 1 to 10 carbon atoms (excluding monovalent heteroatom-containing groups having 1 to 10 carbon atoms) (hereinafter also referred to as "organic group (A)"). Ａ In the structure constituting the formula (I), when the proportion of hydrogen atoms is x, the proportion of monovalent heteroatom-containing groups having 1 to 10 carbon atoms is y, and the proportion of monovalent organic groups having 1 to 10 carbon atoms is z, the compound as a whole satisfies the relationships x + y + z = 100, 20 ≦ x ≦ 95, and 5 ≦ y ≦ 80.

[0034] R Ａ The monovalent heteroatom-containing group having 1 to 10 carbon atoms represented by the formula (I) is the same as the above-mentioned R ０ and R １ Among the monovalent organic groups having 1 to 40 carbon atoms represented by the formula (I), a group corresponding to 1 to 10 carbon atoms and having the above-mentioned divalent heteroatom-containing linking group or monovalent heteroatom-containing substituent can be suitably used.

[0035] The heteroatom-containing group preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 4 carbon atoms.

[0036] The heteroatom-containing group is —O—, —CO—, —S—, or —SO ２ -, -NR'- (R' is a monovalent organic group), -NO ２and —CN. Among these, the heteroatom-containing group more preferably has at least one oxygen atom.

[0037] Examples of the heteroatom-containing group include structures represented by the following formulae (α-1) to (α-12), (β-1) to (β-8), and (γ-1) to (γ-8), where * represents a bond to an oxygen atom.

[0038]

[0039]

[0040]

[0041] R Ａ The organic group (A) represented by the above R ０ and R １ Among the monovalent organic groups having 1 to 40 carbon atoms represented by the formula (I), groups having 1 to 10 carbon atoms can be preferably used. Ａ The organic group (A) represented by the formula (I) is preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a chain hydrocarbon group having 1 to 8 carbon atoms, and even more preferably an unsaturated chain hydrocarbon group having 2 to 6 carbon atoms.

[0042] The above R Ａ In the structure constituting the formula (I), the proportion x of hydrogen atoms satisfies the relationship 20≦x≦95. The lower limit of the proportion x is preferably 30, more preferably 40, even more preferably 50, and particularly preferably 60. The upper limit of the proportion x is preferably 90, more preferably 85, even more preferably 80, and particularly preferably 75.

[0043] The above R Ａ In the structure constituting the formula (I), the proportion y of monovalent heteroatom-containing groups having 1 to 10 carbon atoms satisfies the relationship 5≦y≦80. The lower limit of the proportion y is preferably 10, more preferably 15, even more preferably 20, and particularly preferably 25. The upper limit of the proportion y is preferably 80, more preferably 70, even more preferably 60, and particularly preferably 50.

[0044] The above R ＡIn the structure constituting the compound [A], the proportion z of the organic group (A) preferably satisfies 0≦z≦50. Ａ When the organic group (A) is present as the hydroxyl group, the lower limit of the ratio z is preferably 1, more preferably 3, and even more preferably 5. The upper limit of the ratio y is preferably 40, more preferably 35, and even more preferably 30.

[0045] Examples of the repeating unit represented by the above formula (1) include repeating units represented by the following formulas (1-1) to (1-22).

[0046]

[0047]

[0048]

[0049] In the above formula, R Ａ is as explained above.

[0050] The lower limit of the weight-average molecular weight of the polymer [A1] is preferably 1,000, more preferably 1,500, and even more preferably 2,000. The upper limit of the molecular weight is preferably 10,000, more preferably 8,000, and even more preferably 6,000. The method for measuring the weight-average molecular weight is as described in the Examples.

[0051] (Method of Producing Polymer [A1]) Polymer [A1] can be typically produced by first preparing a compound represented by the formula (1) Ar １ and an aromatic ring compound as a precursor having a phenolic hydroxyl group to give R ０ and R １ The precursor polymer is produced by acid addition condensation with an aldehyde derivative as a precursor to give the above-mentioned polymer. The aldehyde derivative may have a phenolic hydroxyl group. The acid catalyst is not particularly limited, and known inorganic acids and organic acids can be used.

[0052] Next, the phenolic hydroxyl group is modified with a modifying agent to form a —OR group in the polymer [A1]. Ａ Introduce R Ａ When a monovalent heteroatom-containing group having 1 to 10 carbon atoms is introduced as the modifying agent, specifically, ＡBy a nucleophilic reaction of the phenolic hydroxyl group with the corresponding halide, acid anhydride, or acid halide, or by the above-mentioned R Ａ By addition reaction of a phenolic hydroxyl group to a carbon-carbon double bond-containing compound corresponding to -OR Ａ The modification rate of the phenolic hydroxyl groups with the modifying agent can be controlled by adjusting the number of moles of the modifying agent relative to the number of moles of the phenolic hydroxyl groups.

[0053] The above R Ａ Examples of the halide corresponding to the above formula (α-1) to (α-12) include compounds in which a halogen atom is bonded to the * part. Ａ Examples of the acid anhydrides or acid halides corresponding to the above formulas (β-1) to (β-8) include compounds in which an acyloxy group or a halogen atom is bonded to the * portion. Ａ Examples of the carbon-carbon double bond-containing compound corresponding to the above formulas (γ-1) to (γ-8) include compounds in which a carbon-carbon double bond is formed between the α-position carbon and the β-position carbon relative to *.

[0054] The nucleophilic reaction can be carried out under basic conditions or in the presence of a base. The addition reaction can be carried out in the presence of an acid catalyst. After the reaction, the polymer [A1] can be obtained through separation, purification, drying, etc. As the reaction solvent, the solvent [B] described below can be suitably used.

[0055] ([A2] Aromatic ring-containing compound) [A2] Aromatic ring-containing compound is -OR Ａ The molecular weight of the aromatic ring-containing compound [A2] is not particularly limited as long as it is a compound having the formula (I) and a molecular weight of 750 to 3000 (excluding compounds corresponding to the polymer [A1]). The lower limit of the molecular weight of the aromatic ring-containing compound [A2] is preferably 750, more preferably 950, and even more preferably 1050. The upper limit of the molecular weight is preferably 3000, more preferably 2500, and even more preferably 2000.

[0056] The aromatic ring-containing compound (A2) is preferably a compound represented by the following formula (3): (In the above formula (3), W is a q-valent group containing a substituted or unsubstituted aromatic ring having 5 to 60 ring members. R ａ is a monovalent group containing an aromatic ring having 5 to 40 ring members. q is an integer of 1 to 10. When q is 2 or more, multiple R ａ are the same or different from each other. W and one or more R ａ At least one of the is -OR Ａ )

[0057] In the above formula (3), one or more R ａ Ga-OR Ａ and preferably has a plurality of R ａ At least one of the groups is -OR Ａ More preferably, the group has a plurality of R ａ All of the above are -OR Ａ It is more preferred that the .alpha.-hydroxybenzoate has the formula:

[0058] The aromatic ring having 5 to 60 ring members in W includes Ar in the above formula (1). １ An aromatic ring having 5 to 40 ring members in the above formula (I) can be preferably employed, which is expanded to have 60 ring members. Examples of the q-valent group containing a substituted or unsubstituted aromatic ring having 5 to 60 ring members represented by W include groups obtained by removing q hydrogen atoms from the above aromatic ring having 5 to 60 ring members.

[0059] When W 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 aryloxy group such as a phenoxy group or a naphthyloxy 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.

[0060] The aromatic ring of W 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.

[0061] The above W is -OR Ａ When W has the formula (I), at least one hydrogen atom of the aromatic ring in W is -OR Ａ It is preferably substituted with

[0062] The above R ａ The aromatic ring having 5 to 40 ring members in the above formula (1) includes Ar １ An aromatic ring having 5 to 40 ring members in the formula R ａ Examples of the monovalent group containing an aromatic ring having 5 to 40 ring members and represented by the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring having 5 to 40 ring members. ４ The aromatic ring in R 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. ａ When has a substituent, the substituent that can be possessed by W can be suitably adopted.

[0063] The above R ａ is preferably a group represented by the following formula (3-1) or (3-2). (In formulas (3-1) and (3-2), X １ and X ２ are each independently a group represented by the following formula (i), (ii), (iii) or (iv): ５ , Ar ６ and Ar ７ L each independently represents a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with two adjacent carbon atoms in the above formulas (3-1) and (3-2). １ and L ２ are each independently a single bond or a divalent organic group having an aromatic ring. * is a bond to the carbon atom in W in the above formula (3). (In formula (i), R １１ and R １２ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １１ and R １２ At least one of the groups is -OR Ａ In formula (ii), R １３ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １４ is a monovalent organic group having 1 to 20 carbon atoms. １３ and R １４ At least one of the groups is -OR Ａ In formula (iii), R １５ is -OR Ａ In formula (iv), R is a monovalent organic group having 1 to 20 carbon atoms. １６ represents a hydrogen atom or -OR Ａ is a monovalent organic group having 1 to 20 carbon atoms and having the formula:

[0064] In the above formulas (3-1) and (3-2), Ar ５ , Ar ６ and Ar ７ (Hereinafter referred to as “Ar ５ ~Ar ７ ") are each independently a substituted or unsubstituted aromatic ring having 6 to 20 ring members that forms a fused ring structure together with two adjacent carbon atoms in the above formulas (3-1) and (3-2). Ar ５ ~Ar ７ The aromatic ring having 6 to 20 ring members in the above formula (1) includes Ar １ Among the aromatic rings having 5 to 40 ring members in the above, aromatic rings having 6 to 20 ring members can be suitably used.

[0065] Ar ５ ~Ar ７ When has a substituent, the substituent that can be possessed by W can be suitably adopted.

[0066] In the above formulas (i), (ii), (iii) and (iv), R １１ , R １２ , R １３ , R １４ , R １５and R １６ (Hereinafter referred to as “R １１ ~R １６ The monovalent organic group having 1 to 20 carbon atoms represented by R ０ and R １ Among the monovalent organic groups having 1 to 40 carbon atoms represented by the following formula, groups having 1 to 20 carbon atoms are exemplified.

[0067] R in the above formula (i) １１ and R １２ and at least one of R in formula (ii). １３ and R １４ and at least one of R in the formula (iii). １５ and R in the above formula (iv) １６ Each of Ar and Ar in the above formula (1) preferably has an aromatic ring having 5 to 40 ring members. １ In this case, at least one of the hydrogen atoms of the aromatic ring is -OR Ａ It is preferable that the aromatic ring is substituted with -OR. Ａ The number is preferably an integer of 1 to 4, more preferably an integer of 1 to 3, and even more preferably 1 or 2.

[0068] In the above formulas (3-1) and (3-2), L １ and L ２ As the divalent organic group having an aromatic ring in the above formula (1), Ar １ Suitable examples of the substituted or unsubstituted group include a substituted or unsubstituted group (hereinafter also referred to as "group (β)") in which two hydrogen atoms have been removed from an aromatic ring having 5 to 40 ring members in the formula: １ and L ２ The divalent organic group having an aromatic ring represented by the formula (β) and the above R １１ ~R １６ and 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: １ and L ２The divalent organic group having an aromatic ring represented by the formula (I) is preferably a substituted or unsubstituted arenediyl group having 6 to 12 ring members, a substituted or unsubstituted alkenediyl group having 2 to 10 carbon atoms, an alkynediyl group having 2 to 10 carbon atoms, or a combination thereof, more preferably a benzenediyl group, a naphthalenediyl group, an ethylenediyl group, an ethynediyl group, or a combination thereof, and even more preferably a benzenediyl group or a combination of a benzenediyl group and an ethynediyl group.

[0069] In the above formulas (3-1) and (3-2), L １ and L ２ is preferably a single bond.

[0070] The above R Ａ In the structure constituting the formula (I), the proportion x of hydrogen atoms, the proportion y of monovalent heteroatom-containing groups having 1 to 10 carbon atoms, and the proportion z of organic groups (A) can each be the same as in the case of polymer [A1].

[0071] Examples of the aromatic ring-containing compound [A2] include compounds represented by the following formulas (3-1) to (3-8).

[0072]

[0073]

[0074] In the above formula, R Ａ is as explained above.

[0075] A typical method for synthesizing the aromatic ring-containing compound [A2] involves first preparing a starting material, such as a ketone or alkyne-substituted fluorene, and synthesizing the basic skeleton by promoting a cyclization reaction of the ketone or alkyne in the presence of a catalyst or the like. Next, the 9-position of the fluorene is modified with an aldehyde compound having a phenolic hydroxyl group. Finally, the -OR group is synthesized by the same method as in the production method of the polymer [A1]. Ａ By introducing the above, an aromatic ring-containing compound [A2] can be produced. Other structures can also be synthesized by appropriately selecting the starting material, the ketone body, the structure of the aldehyde compound having a phenolic hydroxyl group, etc.

[0076] The content of the compound [A] in the components other than the solvent in the composition for forming a resist underlayer film is 50% by mass or more. The lower limit of the content is preferably 60% by mass, more preferably 70% by mass, even more preferably 80% by mass, and particularly preferably 90% by mass. The upper limit of the content is preferably 100% by mass (i.e., the composition for forming a resist underlayer film contains only the compound [A] other than the solvent). When the composition for forming a resist underlayer film contains an optional component, the upper limit of the content is preferably 99% by mass, more preferably 98% by mass.

[0077] The lower limit of the content of the compound [A] in the composition is preferably 0.01 mass%, more preferably 0.05 mass%, even more preferably 0.1 mass%, and particularly preferably 0.5 mass%, based on the total mass of the compound [A] and the solvent [B]. The upper limit of the content is preferably 30 mass%, more preferably 20 mass%, even more preferably 10 mass%, and particularly preferably 5 mass%, based on the total mass of the compound [A] and the solvent [B].

[0078] <Solvent (B)> The solvent (B) is not particularly limited as long as it can dissolve or disperse the compound (A) and any optional components contained as needed.

[0079] Examples of the solvent (B) include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, etc. The solvent (B) can be used alone or in combination of two or more.

[0080] 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.

[0081] 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.

[0082] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, and n-propanol, and polyalcohol solvents such as ethylene glycol and 1,2-propylene glycol.

[0083] Examples of the ketone solvent include chain ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0084] Examples of ether solvents 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.

[0085] Examples of nitrogen-containing solvents include chain nitrogen-containing solvents such as N,N-dimethylacetamide, and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0086] The solvent (B) is preferably an ester solvent or a ketone solvent, more preferably a polyhydric alcohol partial ether carboxylate solvent or a cyclic ketone solvent, and even more preferably propylene glycol monomethyl ether acetate or cyclohexanone.

[0087] The lower limit of the content of the solvent (B) in the composition is preferably 50% by mass, more preferably 60% by mass, even more preferably 70% by mass, and particularly preferably 80% by mass, and the upper limit of the content is preferably 99.99% by mass, more preferably 99.98% by mass, even more preferably 99.9% by mass, and particularly preferably 99.5% by mass.

[0088] [Optional Components] The film-forming composition may contain optional components to the extent that the effects of the present invention are not impaired. Examples of optional components include acid generators, crosslinkers, surfactants, sensitizers, antifoaming agents, and other polymers different from the polymer [A1]. The optional components may be used alone or in combination of two or more. Examples of known antifoaming agents include alcohol antifoaming agents, phosphate ester antifoaming agents, fatty acid ester antifoaming agents, polyether antifoaming agents, and silicone antifoaming agents. Examples of fatty acid ester antifoaming agents include methyl laurate, methyl palmitate, methyl stearate, propyl butyrate, butyl butyrate, ethyl isovalerate, and isobutyl propionate, with propyl butyrate and butyl butyrate being preferred. Ketone solvents such as 2-heptanone may also be used as antifoaming agents. Examples of the other polymers include polymers having repeating units containing a sulfonate ester structure and polymers having repeating units containing a structure in which two perfluoroalkyl groups and one hydroxyl group are bonded to one carbon atom.

[0089] [Method for preparing composition for forming resist underlayer film] The composition for forming resist underlayer film can be prepared by mixing the compound [A], the solvent [B], 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.

[0090] [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 the substrate. If the substrate has a pattern, this step is preferably omitted.

[0091] 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.

[0092] 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 the resist underlayer film, 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 manufactured by 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).

[0093] When a silicon-containing film is formed indirectly on a substrate, for example, a low dielectric insulating film formed on the substrate, a metal hard mask (TiO ２ and the like), when a silicon-containing film is formed on a carbon film by a CVD method.

[0094] [Coating Step (I)] In this step, the composition for forming a resist underlayer film is directly or indirectly coated onto a substrate. The method for coating the composition for forming a resist underlayer film is not particularly limited, and can be performed by any appropriate method, such as spin coating, casting coating, or roll coating. This forms a coated film, and the resist underlayer film is formed by volatilization of the solvent [B].

[0095] In addition, when the composition for forming a resist underlayer film is indirectly applied to a substrate, for example, the composition for forming a resist underlayer film is applied onto an organic underlayer film formed on a substrate having no pattern.

[0096] The substrate may have a pattern. In this case, it is preferable to apply the resist underlayer film-forming composition directly to the substrate. Since the resist underlayer film-forming composition has excellent filling properties and flatness, even when the substrate has a pattern, it is possible to form a good resist underlayer film while filling the gaps between the patterns. Examples of the pattern shape include a trench pattern, a line-and-space pattern, a hole pattern, and a pillar pattern. Examples of trench patterns and line-and-space patterns include patterns containing recesses with a width of 5 nm to 100 nm and a depth of 5 nm to 500 nm. Examples of hole patterns include patterns containing holes with a diameter of 5 nm to 100 nm and a depth of 5 nm to 500 nm. Examples of pillar patterns include, for example, a rectangular pillar pattern containing pillars with a side length of 5 nm to 100 nm and a height of 5 nm to 500 nm, and a cylindrical pillar pattern containing pillars with a diameter of 5 nm to 100 nm and a height of 5 nm to 500 nm.

[0097] 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 (B).

[0098] The coating film may be heated in an air atmosphere or a nitrogen atmosphere. The lower limit of the heating temperature is preferably 200°C, more preferably 250°C, and still more preferably 300°C. The upper limit of the heating temperature is preferably 550°C, more preferably 500°C, and still more preferably 450°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.

[0099] After the coating step (I), the resist underlayer film may be exposed to light. After the coating step, the resist underlayer film may be exposed to plasma. After the coating step, ions may be implanted into the resist underlayer film. Exposing the resist underlayer film to light improves the etching resistance of the resist underlayer film. Exposing the resist underlayer film to plasma improves the etching resistance of the resist underlayer film. Implanting ions into the resist underlayer film improves the etching resistance of the resist underlayer film.

[0100] The radiation used to expose the resist underlayer film is appropriately selected from 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.

[0101] The method of exposing the resist underlayer film to plasma includes, for example, a direct method in which the substrate is placed in a gas atmosphere and plasma discharge is performed. The conditions for plasma exposure are typically a gas flow rate of 50 cc / min to 100 cc / min and a supplied power of 100 W to 1,500 W.

[0102] The lower limit of the plasma exposure time is preferably 10 seconds, more preferably 30 seconds, and even more preferably 1 minute, and the upper limit of the time is preferably 10 minutes, more preferably 5 minutes, and even more preferably 2 minutes.

[0103] The plasma may be, for example, H ２ Plasma is generated in an atmosphere of a mixed gas of H gas and Ar gas. ２ In addition to gas and Ar gas, CF ４ Gas and CH ４ A carbon-containing gas such as H ２ CF 4 instead of either or both of the gas and Ar. ４ Gas, NF ３ Gas, CHF ３ Gas, CO ２ Gas, CH ２ F ２ Gas, CH ４ Gas and C ４ F ８ At least one of the gases may be introduced.

[0104] Ion implantation of the resist underlayer film implants dopants into the resist underlayer film. The dopants may be selected from the group consisting of boron, carbon, nitrogen, phosphorus, arsenic, aluminum, and tungsten. The implantation energy used to energize the dopants may range from about 0.5 keV to 60 keV, depending on the type of dopant used and the desired implant depth.

[0105] The lower limit of the average thickness of the resist underlayer film formed is preferably 1 nm, more preferably 3 nm, and even more preferably 5 nm. The upper limit of the average thickness is preferably 500 nm, more preferably 200 nm, and even more preferably 100 nm. The average thickness is measured according to the method described in the Examples.

[0106] [Coating Step (II)] In this step, a resist film-forming composition is applied directly or indirectly to the resist underlayer film formed in the resist underlayer film-forming composition application step. The method for applying the resist film-forming composition is not particularly limited, and examples thereof include a rotary coating method.

[0107] An example of a case where the resist film-forming composition is indirectly applied to the resist underlayer film is a case where the resist film-forming composition is applied onto a surface modified film formed on the resist underlayer film.

[0108] To explain this step in more detail, for example, a resist film-forming composition is applied so that the resist film to be formed has a predetermined thickness, and then the composition is pre-baked (hereinafter also referred to as "PB") to volatilize the solvent in the applied film, thereby forming a resist film.

[0109] 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.

[0110] The resist film-forming composition used in this step is preferably a composition that is subjected to exposure to extreme ultraviolet rays, and examples thereof include positive or negative chemically amplified resist compositions that contain a radiation-sensitive acid generator, and metal-containing resist compositions that contain a metal such as tin, zirconium, or hafnium.

[0111]

[0043] In this step, the resist film formed in the resist film-forming composition application step is exposed to extreme ultraviolet (EUV) rays. The exposure conditions can be appropriately determined depending on the type of resist film-forming composition used, etc.

[0112] 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.

[0113] [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.

[0114] 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.

[0115] Examples of organic solvent developers for use in organic solvent development include those exemplified above as the solvent [B]. As the organic solvent developer, an ester solvent, an ether solvent, an alcohol solvent, a ketone solvent, and / or a hydrocarbon solvent is preferred, a ketone solvent is more preferred, and 2-heptanone is particularly preferred.

[0116] In this step, washing and / or drying may be carried out after the development.

[0117] [Etching Step] Subsequently, etching may be performed using the resist pattern (and resist underlayer film pattern) formed in the development step as a mask. The etching may be performed once or multiple times, i.e., 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. From the viewpoint of obtaining a better shape of the pattern on the substrate, dry etching is preferred. For this dry etching, a gas plasma such as oxygen plasma is used, for example. By the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0118] 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 , 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.

[0119] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0120] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The Mw and Mn of the polymer were 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.

[0121] [Modification Rate of Phenolic Hydroxyl Groups] The modification rate of phenolic hydroxyl groups of compound [A] was calculated based on the number of hydroxy groups in the raw materials used in the synthesis and the number of modifiers used to modify the phenolic hydroxyl groups.

[0122] [Average Film Thickness] The average film thickness was determined by measuring the film thickness at 9 arbitrary positions at 5 cm intervals, including the center of the resist underlayer film formed on a silicon wafer (substrate), using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D"), and calculating the average of these film thicknesses.

[0123] <Synthesis of Compound [A]> Compounds (p-1) to (p-5) were synthesized as raw materials for compound [A] according to the following procedure.

[0124] Synthesis Example 1-1 (Synthesis of Compound (p-1)) A reaction vessel was charged with 10.0 g of 2,7-dihydroxynaphthalene, 6.6 g of benzaldehyde, and 49.8 g of 1-butanol under a nitrogen atmosphere, and the mixture was stirred to dissolve the compound. 8.8 g of a 1-butanol solution of 2.4 g of p-toluenesulfonic acid monohydrate was added to the reaction vessel, and the mixture was heated to 110°C and reacted for 12 hours. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and 100 g of methyl isobutyl ketone and 200 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was washed several times with water. The mixture was then concentrated using an evaporator, and the residue was added dropwise to 100 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50 g of methanol. The mixture was then dried in a vacuum dryer at 60°C for 12 hours to obtain compound (p-1) having a repeating unit represented by the following formula (p-1). The Mw of the compound (p-1) was 2,560.

[0125]

[0126] Synthesis Example 1-2 (Synthesis of Compound (p-2)) Compound (p-2) having a repeating unit represented by the following formula (p-2) was obtained by reaction under the same conditions as in Synthesis Example 1-1, except that 13.7 g of 1-hydroxypyrene was used instead of 10.0 g of 2,7-dihydroxynaphthalene and 8.7 g of 3,4-dihydroxybenzaldehyde was used instead of 6.6 g of benzaldehyde. The Mw of compound (p-2) was 3,800.

[0127]

[0128] Synthesis Example 1-3 (Synthesis of Compound (p-3)) Compound (p-3) having a repeating unit represented by the following formula (p-3) was obtained by reaction under the same conditions as in Synthesis Example 1-1, except that 18.1 g of 1,1-bis(4-hydroxyphenyl)-1-phenylethane was used instead of 10.0 g of 2,7-dihydroxynaphthalene and 8.7 g of 2,4-dihydroxybenzaldehyde was used instead of 6.6 g of benzaldehyde. The Mw of compound (p-3) was 4,150.

[0129]

[0130] [Synthesis Example 1-4] (Synthesis of compound (p-4))

[0131] In a reaction vessel, 10.0 g of 1,3,5-benzenetriyltris-9H-fluorene, 7.1 g of 4-hydroxybenzaldehyde, and 60.0 g of dimethylacetamide were added and suspended under a nitrogen atmosphere. 8.8 g of diazabicycloundecene was added and the mixture was allowed to react at 120°C for 12 hours. After the reaction was completed, 300.0 g of methyl isobutyl ketone and 200.0 g of a 5% aqueous oxalic acid solution were added and the organic phase was separated. The organic phase was washed with water several times, then concentrated using an evaporator and added dropwise to 200 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50.0 g of methanol. The mixture was then dried in a vacuum dryer at 60°C for 12 hours to obtain compound (p-4) represented by the following formula (p-4).

[0132]

[0133] Synthesis Example 1-5 Synthesis of Compound (p-5) Compound (p-5) represented by the following formula (p-5) was obtained by reaction under the same conditions as in Synthesis Example 1-4, except that 8.0 g of 3,4-dihydroxybenzaldehyde was used instead of 7.1 g of 4-hydroxybenzaldehyde.

[0134]

[0135] The following compounds (a-1) to (a-8), (b-1) to (b-3), (c-1) to (c-4), and (d-1) to (d-2) were used as modifying agents for the phenolic hydroxyl group of compound [A]. Note that compounds (a-1) to (a-8), (b-1) to (b-3), and (c-1) to (c-4) provide heteroatom-containing groups, and compounds (d-1) to (d-2) provide organic groups other than the heteroatom-containing groups (i.e., organic group (A)).

[0136]

[0137]

[0138]

[0139]

[0140] Each of the compounds [A] was synthesized according to the following procedure.

[0141] Synthesis Example 2-1 (Synthesis of Compound (A-1)) In a reaction vessel under a nitrogen atmosphere, 10.0 g of compound (p-1) was dissolved in 50.0 g of tetrahydrofuran, the solution was cooled to 10°C or below, 3.12 g of N,N-diisopropylethylamine was added, and 1.95 g of chloromethyl methyl ether (a-1) was added dropwise. The temperature was returned to room temperature and the reaction was carried out for 1 hour. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and 150 g of methyl isobutyl ketone and 200 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was washed several times with water. Thereafter, the solution was concentrated using an evaporator, and the residue was dropped into 150 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50 g of methanol. Thereafter, the precipitate was dried in a vacuum dryer at 60°C for 12 hours to obtain compound (A-1). In the formula, the numerical values ​​are R Ａ where x is the proportion of hydrogen atoms constituting the formula, y is the proportion of heteroatom-containing groups that are modifying groups (and z is the proportion of organic groups (A), if present). * is a bond to an oxygen atom. The same applies to the following formulas.

[0142]

[0143] [Synthesis Examples 2-2 to 2-6, 2-11 to 2-13] (Synthesis of Compounds (A-2) to (A-6) and (A-11) to (A-13)) Compounds (A-2) to (A-6) and (A-11) to (A-13) were obtained as products under the same reaction conditions as in Synthesis Example A-1, except that the modifying agents shown in Table 1 were used.

[0144]

[0145]

[0146] Synthesis Example 2-7 (Synthesis of Compound (A-7)) In a reaction vessel under a nitrogen atmosphere, 10.0 g of compound (p-1) was dissolved in 50.0 g of tetrahydrofuran, 0.49 g of N,N-dimethylaminopyridine was added, and 2.47 g of acetic anhydride (b-1) was added dropwise, followed by a reaction at 50°C for 1 hour. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and 150 g of methyl isobutyl ketone and 200 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was washed several times with water. Thereafter, the mixture was concentrated using an evaporator, and the residue was added dropwise to 150 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50 g of methanol. Thereafter, the mixture was dried in a vacuum dryer at 60°C for 12 hours to obtain compound (A-7) having a repeating unit represented by the following formula (A-7).

[0147]

[0148] Synthesis Example 2-8 (Synthesis of Compound (A-8)) Compound (A-8) was obtained as a product under the same reaction conditions as in Synthesis Example 2-7, except that the modifying agent shown in Table 1 was used.

[0149]

[0150] Synthesis Example 2-9 (Synthesis of Compound (A-9)) In a reaction vessel under a nitrogen atmosphere, 10.0 g of compound (p-1) was dissolved in 50.0 g of tetrahydrofuran, 1.74 g of ethyl vinyl ether (c-1) was added, and 0.61 g of pyridinium p-toluenesulfonate was added dropwise, followed by a reaction at 50°C for 3 hours. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and 150 g of methyl isobutyl ketone and 200 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was washed several times with water. Thereafter, the mixture was concentrated using an evaporator, and the residue was added dropwise to 150 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50 g of methanol. Thereafter, the mixture was dried in a vacuum dryer at 60°C for 12 hours to obtain compound (A-9) having a repeating unit represented by the following formula (A-9).

[0151]

[0152] Synthesis Example 2-10 (Synthesis of Compound (A-10)) Compound (A-10) was obtained as a product under the same reaction conditions as in Synthesis Example 2-9, except that the modifying agent shown in Table 1 was used.

[0153]

[0154] Synthesis Example 2-14 (Synthesis of Compound (A-14)) In a reaction vessel under a nitrogen atmosphere, 10.0 g of compound (p-1) was dissolved in 50.0 g of tetrahydrofuran, the solution was cooled to below 10°C, 8.33 g of N,N-diisopropylethylamine was added, 1.30 g of chloromethyl methyl ether (a-1) was added dropwise, and the mixture was allowed to react for 1 hour after returning to room temperature. Thereafter, 2.87 g of propargyl bromide (d-1) was added dropwise, and the mixture was allowed to react at 60°C for 2 hours. After completion of the reaction, the reaction solution was transferred to a separatory funnel, and the organic phase was washed by adding 150 g of methyl isobutyl ketone and 200 g of water. After separating the aqueous phase, the obtained organic phase was washed several times with water. Thereafter, the mixture was concentrated using an evaporator, and the residue was added dropwise to 150 g of methanol to obtain a precipitate. The precipitate was collected by suction filtration and washed several times with 50 g of methanol. Thereafter, the mixture was dried in a vacuum dryer at 60° C. for 12 hours to obtain a compound (A-14) having a repeating unit represented by the following formula (A-14).

[0155]

[0156] [Synthesis Examples 2-15, 2-28 to 2-29] (Synthesis of Compounds (A-15), (A-28) to (A-29)) Compounds (A-15), (A-28) to (A-29) were obtained as products under the same reaction conditions as in Synthesis Example 2-14, except that the compounds and modifying agents shown in Table 1 were used.

[0157]

[0158]

[0159] [Synthesis Examples 2-16 to 2-21] (Synthesis of Compounds (A-16) to (A-21)) Compounds (A-16) to (A-21) were obtained as products under the same reaction conditions as in Synthesis Example 2-1, except that the compounds and modifying agents shown in Table 1 were used.

[0160]

[0161]

[0162]

[0163] Synthesis Example 2-22 Synthesis of Compound (A-22) Compound (A-22) was obtained as a product under the same reaction conditions as in Synthesis Example 2-7, except that the compounds and modifying agents shown in Table 1 were used.

[0164]

[0165] [Synthesis Examples 2-23 to 2-24] (Synthesis of Compounds (A-23) to (A-24)) Compounds (A-23) to (A-24) were obtained as products under the same reaction conditions as in Synthesis Example 2-9, except that the compounds and modifying agents shown in Table 1 were used.

[0166]

[0167] [Synthesis Examples 2-25 to 2-27, 2-30 to 2-31] (Synthesis of compounds (A-25) to (A-27) and (A-30) to (A-31)) Compounds (A-25) to (A-27) and (A-30) to (A-31) were obtained as products under the same reaction conditions as in Synthesis Example A-1, except that the compounds and modifying agents shown in Table 1 were used.

[0168]

[0169]

[0170]

[0171]

[0172] <Preparation of Composition> [A] Compound, comparative compound, [B] solvent, [C] acid generator, [D] crosslinking agent and [E] other polymer used in the preparation of the composition are shown below.

[0173] [[A] Compounds] A-1 to A-31: Compounds (A-1) to (A-31) synthesized above

[0174] [Comparative compounds] p-1: Compound (p-1) synthesized above p-5: Compound (p-5) synthesized above

[0175] [B] Solvent: B-1: Propylene glycol monomethyl ether acetate B-2: Cyclohexanone

[0176] [[C] Acid Generator] C-1: Compound represented by the following formula (C-1):

[0177] [[D] Crosslinking Agent] D-1: A compound represented by the following formula (D-1):

[0178] D-2: A compound represented by the following formula (D-2)

[0179] D-3: A compound represented by the following formula (D-3):

[0180] D-4: A compound represented by the following formula (D-4):

[0181] D-5: A compound represented by the following formula (D-5):

[0182] D-6: A compound represented by the following formula (D-6)

[0183] D-7: A compound represented by the following formula (D-7)

[0184] D-8: A compound represented by the following formula (D-8)

[0185] D-9: A compound represented by the following formula (D-9)

[0186] D-10: A compound represented by the following formula (D-10):

[0187] D-11: A compound represented by the following formula (D-11):

[0188] D-12: A compound represented by the following formula (D-12):

[0189] D-13: A compound represented by the following formula (D-13):

[0190] D-14: A compound represented by the following formula (D-14):

[0191] D-15: A compound represented by the following formula (D-15):

[0192] D-16: A compound represented by the following formula (D-16):

[0193] [E] Other polymers E-1: Polymer having a repeating unit represented by the following formula (E-1) (Mw: 2500) E-2: Polymer having a repeating unit represented by the following formula (E-2) (Mw: 3000) E-3: Polymer having a repeating unit represented by the following formula (E-3) (Mw: 3500)

[0194]

[0195] Example 1-1 2 parts by mass of (A-1) as the compound [A] was dissolved in 98 parts by mass of (B-1) as the solvent [B]. The resulting solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore size of 0.45 μm to prepare composition (J-1).

[0196] Examples 1-2 to 1-61 and Comparative Examples 1-1 to 1-2 Compositions (J-2) to (J-61) and (CJ-1) to (CJ-2) were prepared in the same manner as in Example 1-1, except that the types and amounts of each component shown in Tables 2-1 and 2-2 below were used. In Table 2, "-" indicates that the corresponding component was not used.

[0197]

[0198]

[0199] <Evaluation> Using the compositions prepared above, the embeddability and flatness were evaluated by the following methods. The evaluation results are also shown in Table 3 below.

[0200] [Filling Ability] The composition was applied by spin coating using a spin coater (Tokyo Electron Limited's "LITHIUS Pro Z") on a substrate on which a trench pattern of 65 nm in depth and 20 nm in width had been formed. The spin coater's rotation conditions were set so as to obtain a substrate with a film having an average thickness of 100 nm. The substrate was then heated at 400°C for 90 seconds in an air atmosphere, and then cooled at 23°C for 60 seconds. The cross-sectional shape of the substrate was observed (200,000x magnification) using a scanning electron microscope (Hitachi High-Technologies Corporation's "S-4800") to evaluate the filling ability. The filling ability was evaluated as "A" (good) when the resist underlayer film was embedded to the bottom of the space pattern of the substrate (when no voids were present), and as "B" (poor) when the resist underlayer film was not embedded to the bottom of the space pattern (when voids were present).

[0201] [Flatness] The composition prepared above was applied by a spin coating method using a spin coater ("CLEAN TRACK ACT12" manufactured by Tokyo Electron Ltd.) onto a silicon substrate 1 having a trench pattern of 150 nm deep and 10 μm wide formed thereon, as shown in Figure 1. Next, the substrate 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 2 having an average thickness of 200 nm in the non-trench pattern area, which was then heated at 350°C for 60 seconds in an air atmosphere and then cooled at 23°C for 60 seconds to obtain a silicon substrate with a resist underlayer film. The cross-sectional shape of the silicon substrate with the resist underlayer film was observed with a scanning electron microscope ("S-4800" manufactured by Hitachi High-Technologies Corporation), and the difference (ΔFT) between the height of the central portion b of the trench pattern of the resist underlayer film 2 and the height of the non-trench pattern portion a located 5 μm from the edge of the trench pattern was used as an index of flatness. Flatness was evaluated as "A" (good) when ΔFT was less than 20 nm, and as "B" (poor) when ΔFT was 20 nm or greater. The height difference shown in FIG. 1 is exaggerated compared to the actual height.

[0202] <Evaluation> Using the compositions prepared above, the rectangularity of resist patterns formed by EUV exposure was evaluated by the following method. The evaluation results are shown in Table 3 below.

[0203] <Preparation of Resist Composition (R-1)> Compound (S-1) used in preparing resist composition (R-1) was synthesized according to 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 mixture was stirred 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 an oxide hydroxide product (i-PrSnO) of the hydrolysis product of isopropyltin trichloride. （３／２－ｘ／２） (OH) ｘ (where 0<x<3 is the structural unit).

[0204] 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 resist composition (R-1).

[0205] [Pattern Rectangularity (EUV Exposure)] The above composition was applied to a 12-inch silicon wafer, 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-1) was applied onto this resist underlayer film by the above-mentioned spin coating method using a spin coater, and after a predetermined time had elapsed, the wafer 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.

[0206]

[0207]

[0208] As can be seen from the results in Tables 3-1 and 3-2, the compositions of the examples and the resist underlayer films formed therefrom were superior in pattern rectangularity compared to the comparative examples. Furthermore, the compositions of the examples and the resist underlayer films formed therefrom were also superior in embedding ability and flatness compared to the comparative examples.

[0209] According to the semiconductor substrate manufacturing method of the present invention, a resist underlayer film having excellent pattern rectangularity is formed, thereby enabling a well-patterned semiconductor substrate to be obtained. According to the resist underlayer film-forming composition of the present invention, a resist underlayer film having excellent pattern rectangularity can be formed. Furthermore, according to the semiconductor substrate manufacturing method of the present invention, a resist underlayer film having excellent embedding properties that allow the substrate pattern to be sufficiently embedded, as well as excellent flatness of the film after embedding, can be formed. According to the resist underlayer film-forming composition of the present invention, a resist underlayer film having excellent embedding properties and flatness can be formed. Therefore, these compositions can be suitably used in the manufacture of semiconductor devices, which are expected to become even more miniaturized in the future.

[0210] 1 Silicon substrate 2 Resist underlayer film

Claims

1. A method for forming a resist underlayer film comprising the steps of: applying a composition for forming a resist underlayer film directly or indirectly to a substrate; applying a composition for forming a resist film directly or indirectly to a resist underlayer film formed by the applying composition for forming a resist underlayer film; exposing the resist film formed by the applying composition for forming a resist film; and developing at least the exposed resist film, wherein the composition for forming a resist underlayer film comprises a compound and a solvent, and the compound is a -OR Ａ With R Ａ is any one of a hydrogen atom, a monovalent heteroatom-containing group having 1 to 10 carbon atoms, and a monovalent organic group having 1 to 10 carbon atoms (excluding monovalent heteroatom-containing groups having 1 to 10 carbon atoms), and the R Ａ In the structure constituting the formula (1), the ratio of hydrogen atoms is x, the ratio of monovalent heteroatom-containing groups having 1 to 10 carbon atoms is y, and the ratio of monovalent organic groups having 1 to 10 carbon atoms is z, and the compound as a whole satisfies the relationships of x + y + z = 100, 20 ≦ x ≦ 95, and 5 ≦ y ≦ 80, and the compound is a polymer having a repeating unit represented by the following formula (1), a molecular weight of 750 or more and 3000 or less, and -OR Ａ or a combination thereof. (In formula (1), Ar １ R is a divalent group having an aromatic ring having 5 to 40 ring members. ０ R is a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. １ is a monovalent organic group having 1 to 40 carbon atoms. １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ ) 2. The heteroatom-containing group is -O-, -CO-, -S-, -SO ２ -, -NR'- (R' is a monovalent organic group), -NO ２ 2. The method for producing a semiconductor substrate according to claim 1, wherein the group comprises at least one selected from the group consisting of -CN and -CN.

3. The method for producing a semiconductor substrate according to claim 1, wherein the heteroatom-containing group has at least one oxygen atom.

4. The method for producing a semiconductor substrate according to any one of claims 1 to 3, wherein the aromatic ring is 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, and a perylene ring.

5. The method for manufacturing a semiconductor substrate according to any one of claims 1 to 3, wherein the substrate has a pattern.

6. The method for producing a semiconductor substrate according to any one of claims 1 to 3, wherein the resist film contains a metal.

7. A compound and a solvent, the compound being -OR Ａ With R Ａ is any one of a hydrogen atom, a monovalent heteroatom-containing group having 1 to 10 carbon atoms, and a monovalent organic group having 1 to 10 carbon atoms (excluding monovalent heteroatom-containing groups having 1 to 10 carbon atoms), and the R Ａ In the structure constituting the formula (1), the ratio of hydrogen atoms is x, the ratio of monovalent heteroatom-containing groups having 1 to 10 carbon atoms is y, and the ratio of monovalent organic groups having 1 to 10 carbon atoms is z, and the compound as a whole satisfies the relationships of x + y + z = 100, 20 ≦ x ≦ 95, and 5 ≦ y ≦ 80, and the compound is a polymer having a repeating unit represented by the following formula (1), a molecular weight of 750 or more and 3000 or less, and -OR Ａ or a combination thereof. (In formula (1), Ar １ R is a divalent group having an aromatic ring having 5 to 40 ring members. ０ R is a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. １ is a monovalent organic group having 1 to 40 carbon atoms. １ , R ０ and R １ At least one selected from the group consisting of -OR Ａ ) 8. The heteroatom-containing group is -O-, -CO-, -S-, -SO ２ -, -NR'- (R' is a monovalent organic group), -NO ２ The composition for forming a resist underlayer film according to claim 7, further comprising at least one selected from the group consisting of -CN and -CN.

9. The composition for forming a resist underlayer film according to claim 7, wherein the heteroatom-containing group has at least one oxygen atom.

10. The composition for forming a resist underlayer film according to any one of claims 7 to 9, wherein the aromatic ring is 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, and a perylene ring.

11. The composition for forming a resist underlayer film according to any one of claims 7 to 9, which is used for embedding a pattern in a substrate having a pattern.

12. The composition for forming a resist underlayer film according to any one of claims 7 to 9, which is used for forming an underlayer film of a metal-containing resist film.

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