Method for manufacturing a semiconductor substrate and composition

Abstract

The purpose is to provide a method for manufacturing a semiconductor substrate and a composition capable of forming a film with excellent etching resistance, heat resistance, and bending resistance. The method comprises a process of coating a composition for forming a resist sublayer film directly or indirectly onto a substrate, a process of forming a resist pattern directly or indirectly on the resist sublayer film formed by the coating process, and a process of performing etching using the resist pattern as a mask, wherein the composition for forming the resist sublayer film contains a polymer having repeating units represented by the following formula (1) and a solvent. (In Equation (1), Ar1 is a divalent group having an aromatic ring with a reducing water of 5 to 40. R0 is a monovalent group having an aromatic ring with a reducing water of 5 to 40 and has at least one group selected from the group consisting of the group represented by Equation (2-1) and the group represented by Equation (2-2).) (In formulas (2-1) and (2-2), R7 is, respectively, independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.)

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a semiconductor substrate, a composition, a polymer, and a method for manufacturing a polymer. Background Technology

[0002] In the manufacture of semiconductor devices, a multilayer resist process is used to form a resist pattern by exposing and developing a resist film stacked through a resist sublayer film, such as an organic sublayer film or a silicon-containing film, on a substrate. In this process, a resist sublayer film is etched using the resist pattern as a mask, and a substrate is further etched using the obtained resist sublayer film pattern as a mask, thereby forming a desired pattern on a semiconductor substrate (see Japanese Patent Publication No. 2004-177668).

[0003] Various studies have been conducted on materials used in compositions for forming such resist underlayers (see International Publication No. 2011 / 108365). Prior art literature

[0004] Japanese Patent Publication No. 2004-177668, International Publication No. 2011 / 108365 The problem to be solved

[0005] In a multilayer resist process, the organic underlayer as the resist underlayer requires etching resistance, heat resistance, and bending resistance.

[0006] The present invention is based on the above circumstances, and its purpose is to provide a method for manufacturing a semiconductor substrate and a composition using a composition capable of forming a film with excellent etching resistance, heat resistance, and bending resistance. means of solving the problem

[0007] In one embodiment, the present invention,

[0008] A process of coating a composition for forming a resist underlayer film directly or indirectly onto a substrate, and

[0009] A process of forming a resist pattern directly or indirectly on a resist underlayer film formed by the above coating process, and

[0010] A process of performing etching using the above resist pattern as a mask

[0011] Includes,

[0012] The above composition for forming a resist underlayer film,

[0013] A polymer having repeating units represented by the following formula (1) (hereinafter also referred to as “[A] polymer”), and

[0014] Solvent (hereinafter also referred to as "[B] Solvent")

[0015] This relates to a method for manufacturing a semiconductor substrate containing

[0016]

[0017] (In formula (1), Ar 1 Silver is a divalent group having an aromatic ring with a reduction water of 5 to 40. R 0 Silver is a monovalent group having an aromatic ring of 5 to 40 reduced waters, and has at least one group selected from the group consisting of the group represented by the following formula (2-1) and the group represented by the following formula (2-2).

[0018]

[0019] (In equations (2-1) and (2-2), R 7 Each is independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.)

[0020] In this specification, "reduced number" refers to the number of atoms constituting a ring. For example, the reduced number of a biphenyl ring is 12, the reduced number of a naphthalene ring is 10, and the reduced number of a fluorene ring is 13.

[0021] In other embodiments, the present invention,

[0022] A polymer having repeating units represented by the following formula (1), and

[0023] menstruum

[0024] This relates to a composition containing

[0025]

[0026] (In formula (1), Ar 1 Silver is a divalent group having an aromatic ring with a reduction water of 5 to 40. R 0 Silver is a monovalent group having an aromatic ring of 5 to 40 reduced waters, and has at least one group selected from the group consisting of the group represented by the following formula (2-1) and the group represented by the following formula (2-2).

[0027]

[0028] (In equations (2-1) and (2-2), R 7 Each is independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.) Effects of the invention

[0029] According to the method for manufacturing the semiconductor substrate, a semiconductor substrate having a good pattern shape can be obtained in order to form a resist underlayer film with excellent etching resistance, heat resistance, and bending resistance. According to the composition, a film with excellent etching resistance, heat resistance, and bending resistance can be formed. Therefore, these can be suitably used for the manufacture of semiconductor devices, etc., which are expected to undergo further miniaturization in the future. Brief explanation of the drawing

[0030] Figure 1 is a schematic plan view illustrating a method for evaluating bending resistance. Specific details for implementing the invention

[0031] Hereinafter, a method for manufacturing a semiconductor substrate and a composition related to each embodiment of the present invention will be described in detail. A combination of suitable modes in the embodiments is also preferred.

[0032] Method for manufacturing a semiconductor substrate

[0033] The method for manufacturing the semiconductor substrate comprises a process of coating a composition for forming a resist underlayer film directly or indirectly onto a substrate (hereinafter also referred to as a “coating process”), a process of forming a resist pattern directly or indirectly onto the resist underlayer film formed by the coating process (hereinafter also referred to as a “resist pattern forming process”), and a process of performing etching using the resist pattern as a mask (hereinafter also referred to as an “etching process”).

[0034] According to the method for manufacturing the semiconductor substrate, by using the composition described below as a composition for forming a resist underlayer film in the coating process, a resist underlayer film with excellent etching resistance, heat resistance, and bending resistance can be formed, and thus a semiconductor substrate having a good pattern shape can be manufactured.

[0035] The method for manufacturing the semiconductor substrate may, if necessary, further include a process for forming a silicon-containing film directly or indirectly on the resist underlayer (hereinafter also referred to as a "silicon-containing film forming process").

[0036] Hereinafter, the composition and each process used in the method for manufacturing the semiconductor substrate are described.

[0037] <Composition>

[0038] The composition for forming a resist underlayer contains [A] a polymer and [B] a solvent. The composition may contain any components within a range that does not impair the effects of the present invention.

[0039] The composition can form a film with excellent etching resistance, heat resistance, and bending resistance by containing [A] a polymer and [B] a solvent. Therefore, the composition can be used as a composition for forming a film. More specifically, the composition can be suitably used as a composition for forming a resist underlayer film in a multilayer resist process.

[0040] Below, each component contained in the composition is described.

[0041] <[A] Polymer>

[0042] [A] The polymer has repeating units represented by the following formula (1). [A] The polymer may have two or more repeating units represented by the following formula (1). The composition may contain one or more types of [A] polymers.

[0043]

[0044] (In formula (1), Ar 1 Silver is a divalent group having an aromatic ring with a reduction water of 5 to 40. R 0 Silver is a monovalent group having an aromatic ring of 5 to 40 reduced waters, and has at least one group selected from the group consisting of the group represented by the following formula (2-1) and the group represented by the following formula (2-2).

[0045]

[0046] (In equations (2-1) and (2-2), R 7 Each is independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.)

[0047] Among the above formula (1), Ar 1 and R 0Examples of aromatic rings having a reduction water of 5 to 40 in the above include, for instance, aromatic hydrocarbon rings such as benzene rings, naphthalene rings, anthracene rings, phenalene rings, phenanthrene rings, pyrene rings, fluorene rings, perylene rings, coronene rings, etc., complex aromatic rings such as furan rings, pyrrole rings, thiophene rings, phosphol rings, pyrazol rings, oxazole rings, isooxazole rings, thiazole rings, pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, triazine rings, etc., or combinations thereof. The above Ar 1 and R 0 Preferably, the aromatic ring is at least one aromatic hydrocarbon ring selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, a fluorene ring, a perylene ring, and a coronene ring. Ar 1 As the aromatic ring, it is more preferable that it be a benzene ring, a naphthalene ring, or a pyrene ring. R 0 As for the aromatic ring, the benzene ring is more preferable.

[0048] Among the above formula (1), Ar 1 and R 0 As a divalent group having an aromatic ring of 5 to 40 reduced water represented by, the above Ar 1 and R 0 Suitable examples include groups excluding two hydrogen atoms from the aromatic ring of 5 to 40 of the reduced water.

[0049] Among the above equations (2-1) and (2-2), R 7 Examples of divalent organic groups having 1 to 20 carbon atoms represented by, for instance, a divalent hydrocarbon group having 1 to 20 carbon atoms, a group having a divalent heteroatom-containing group between carbons of the hydrocarbon group, a group having some or all of the hydrogen atoms of the hydrocarbon group substituted with a monovalent heteroatom-containing group, or a combination thereof.

[0050] Examples of divalent hydrocarbon groups having 1 to 20 carbon atoms include divalent chain hydrocarbon groups having 1 to 20 carbon atoms, divalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, or combinations thereof.

[0051] In this specification, "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" includes saturated hydrocarbon groups and unsaturated hydrocarbon groups. "Chain hydrocarbon group" means a hydrocarbon group composed solely of a chain structure without including a ring structure, and includes both straight-chain hydrocarbon groups and branched-chain hydrocarbon groups. "Alicyclic hydrocarbon group" means a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes both single-ring alicyclic hydrocarbon groups and multi-ring alicyclic hydrocarbon groups (however, it is not necessary to be composed solely of an alicyclic structure, and may include a chain structure in a part thereof). "Aromatic hydrocarbon group" means a hydrocarbon group that includes an aromatic ring structure as a ring structure (however, it does not need to be composed solely of an aromatic ring structure, and may include a ring structure or a chain structure in part thereof).

[0052] Examples of divalent chain hydrocarbon groups having 1 to 20 carbon atoms include methanediyl groups, ethanediyl groups, propanediyl groups, butanediyl groups, hexanediyl groups, octanediyl groups, etc. Among these, alkanediyl groups having 1 to 8 carbon atoms are preferred.

[0053] Examples of divalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include cycloalkanedyl groups such as cyclopentanediyl and cyclohexanedyl; cycloalkenedyl groups such as cyclopentenediyl and cyclohexendiyl; exchange-saturated hydrocarbon groups such as norbornandyl, adamantandiyl and tricyclodecanediyl; and exchange-unsaturated hydrocarbon groups such as norbornenediyl and tricyclodecenediyl.

[0054] Examples of divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include phenylene groups, naphthalenediyl groups, anthracenediyl groups, pyrenediyl groups, toluenediyl groups, xylenediyl groups, etc.

[0055] Examples of heteroatoms constituting a divalent or monovalent heteroatom-containing group include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, etc. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0056] Examples of divalent heteroatom-containing groups include -CO-, -CS-, -NH-, -O-, -S-, and groups combining these.

[0057] Examples of monovalent heteroatom-containing groups include hydroxyl groups, sulfanyl groups, cyano groups, nitro groups, halogen atoms, etc.

[0058] R 7 As for the group, a divalent hydrocarbon group having 1 to 10 carbon atoms, such as a methanediyl group, an ethanediyl group, or a phenylene group, -O-, or a combination thereof is preferred, and a methanediyl group, or a combination of a methanediyl group and -O- is more preferred.

[0059] The above R 0 This has a mechanism represented by the above formula (2-1), and it is preferable that the mechanism be represented by the following formula (2-1-1).

[0060]

[0061] The above R 0 It is a monovalent group having an aromatic ring of 5 to 40 reduced water, and preferably has at least two groups selected from the group consisting of the group represented by Formula (2-1) and the group represented by Formula (2-2). 0It is more preferable to have at least three groups selected from the group consisting of the group represented by the above formula (2-1) and the group represented by the above formula (2-2).

[0062] The above Ar 1 It is preferable to have at least one group selected from the group consisting of the group represented by the above formula (2-1) and the group represented by the above formula (2-2).

[0063] Ar 1 and R 0 The group may have substituents other than the group represented by the formula (2-1) and the group represented by the formula (2-2). Examples of substituents 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 methoxycarbonyl 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, a hydroxyl group, etc.

[0064] Examples of the repeating units represented by the above formula (1) include the repeating units represented by the following formulas (1-1) to (1-28). Even if multiple repeating units are connected among the following formulas, each repeating unit can be adopted independently.

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] Among these, the repeating units represented by the above formulas (1-1) to (1-10), (1-13) to (1-17), and (1-22) to (1-28) are preferred, and in particular, the repeating units represented by the above formulas (1-5) to (1-8) are preferred.

[0071] [A] The polymer may also have repeating units represented by the following formula (3).

[0072]

[0073] (In formula (3), Ar 5 is a divalent group having an aromatic ring with a reduction water of 5 to 40. R 1 It is silver, a hydrogen atom, or a monovalent organic group having 1 to 60 carbon atoms (however, R of the above formula (1) 0 Excludes the corresponding units.))

[0074] Ar 5 As for the reducing water of 5 to 40 in the above, the Ar of formula (1) 1 In this case, 5 to 40 aromatic rings of reduced water can be suitably employed.

[0075] Ar 5 As a divalent group having an aromatic ring of 5 to 40 reduced water represented by, the above Ar 5 Suitable examples include a group having two hydrogen atoms removed from an aromatic ring of 5 to 40 reduced water.

[0076] R 1 As a monovalent organic group having 1 to 60 carbon atoms represented by, R of the above formula (1) 0Groups other than those corresponding to are not specifically limited, and examples include monovalent hydrocarbon groups having 1 to 60 carbon atoms, groups having divalent heteroatom-containing groups between carbons of the hydrocarbon group, groups in which some or all of the hydrogen atoms of the hydrocarbon group are substituted with monovalent heteroatom-containing groups, or combinations thereof. As for these groups, in the above formulas (i), (ii), (iii), and (iv), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 As a group constituting a monovalent organic group having 1 to 20 carbon atoms represented by, a group extending the exemplified group up to 60 carbon atoms can be suitably adopted.

[0077] As for the repeating unit represented by the above formula (3), examples include the repeating unit represented by the following formulas (3-1) to (3-8).

[0078]

[0079] [A] As a lower limit of the weight-average molecular weight of the polymer, 500 is preferred, 1000 is more preferred, 1500 is even more preferred, and 2000 is particularly preferred. As an upper limit of the molecular weight, 10000 is preferred, 8000 is more preferred, 7000 is even more preferred, and 6000 is particularly preferred. In addition, the method for measuring the weight-average molecular weight follows the description in the example.

[0080] As a lower limit for the content ratio of [A] polymer in the composition, 2 mass% is preferred, 4 mass% is more preferred, 6 mass% is even more preferred, and 8 mass% is particularly preferred, based on the total mass of [A] polymer and [B] solvent. As an upper limit for the content ratio, 30 mass% is preferred, 25 mass% is more preferred, 20 mass% is even more preferred, and 15 mass% is particularly preferred, based on the total mass of [A] polymer and [B] solvent.

[0081] <[A] Method for manufacturing a polymer>

[0082] [A] The polymer is, typically, the Ar of the above formula (1). 1 An aromatic compound as a precursor having a phenolic hydroxyl group that imparts, and R of the above formula (1). 0 It can be prepared by acid addition condensation of an aldehyde derivative having a phenolic hydroxyl group as a precursor, followed by a nucleophilic substitution reaction with a phenolic hydroxyl group on a halogenated hydrocarbon corresponding to the group represented by formula (2-1) or (2-2). The acid catalyst is not particularly limited and known inorganic and organic acids may be used. After the reaction, the polymer [A] can be obtained by separation, purification, drying, etc. As a reaction solvent, the solvent [B] described later may be suitably employed.

[0083] <[B] Solvent>

[0084] [B] The solvent is not particularly limited as long as it can dissolve or disperse the [A] polymer and, if necessary, any component contained therein.

[0085] [B] Examples of solvents include hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, etc. [B] Solvents may be used individually or in combination of two or more types.

[0086] 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.

[0087] Examples of ester-based solvents include carbonate-based solvents such as diethyl carbonate, acetic acid monoester-based solvents such as methyl acetate and ethyl acetate, lactone-based solvents such as γ-butyrolactone, polyhydric alcohol portion ethercarboxylate-based solvents such as diethylene glycol monomethyl ether and propylene glycol monomethyl ether, and lactic acid ester-based solvents such as methyl lactate and ethyl lactate.

[0088] Examples of alcohol-based solvents include monoalcohol-based solvents such as methanol, ethanol, and n-propanol, and polyalcohol-based solvents such as ethylene glycol and 1,2-propylene glycol.

[0089] Examples of ketone-based solvents include chain-based ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

[0090] Examples of ether-based solvents include chain ether-based solvents such as n-butyl ether, polyhydric alcohol ether-based solvents such as cyclic ether-based solvents such as tetrahydrofuran, and polyhydric alcohol partial ether-based solvents such as diethylene glycol monomethyl ether.

[0091] Examples of nitrogen-containing solvents include chain nitrogen-containing solvents such as N,N-dimethylacetamide and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

[0092] [B] As a solvent, an ester-based solvent or a ketone-based solvent is preferred, a polyhydric alcohol portion ethercarboxylate-based solvent or a cyclic ketone-based solvent is more preferred, and propylene glycol monomethyl ether acetate or cyclohexanone is even more preferred.

[0093] As a lower limit for the content ratio of [B] solvent in the composition, 50 mass% is preferred, 60 mass% is more preferred, and 70 mass% is even more preferred. As an upper limit for the content ratio, 99.9 mass% is preferred, 99 mass% is more preferred, and 95 mass% is even more preferred.

[0094] The content ratio of hydrogen atoms in the coating film of the composition after heating it at 400°C for 90 seconds is preferably 26.0 atm% or less, more preferably 25.0 atm% or less, even more preferably 24.0 atm% or less, and particularly preferably 23.0 atm% or less. In addition, the content ratio of carbon atoms in the coating film of the composition after heating it at 400°C for 90 seconds is preferably 53.0 atm% or more, more preferably 54.0 atm% or more, even more preferably 55.0 atm% or more, and particularly preferably 56.0 atm% or more. By setting the content ratio of hydrogen atoms or carbon atoms after heating the coating film formed by the above composition to the above range, the etching resistance or bending resistance of the resist underlayer film formed by the composition can be further improved. In addition, the method for measuring the content ratio of hydrogen atoms and carbon atoms after heating of the coating film follows the description in the examples.

[0095] [Optional ingredient]

[0096] The composition may contain optional components within a range that does not impair the effects of the present invention. Examples of optional components include acid-generating agents, crosslinking agents, surfactants, etc. Optional components may be used individually or in combination of two or more. The content ratio of optional components in the composition may be appropriately determined according to the type of optional component, etc.

[0097] [Method of preparing the composition]

[0098] The composition can be prepared by [A] mixing a polymer, [B] a solvent, and optionally any component in a predetermined ratio, and preferably by filtering the resulting mixture through a membrane filter with a hole diameter of 0.5 μm or less.

[0099] [Painting Process]

[0100] In this process, a composition for forming a resist underlayer is coated directly or indirectly onto a substrate. In this process, the composition described above is used as the composition for forming a resist underlayer.

[0101] The coating method for the composition for forming a resist underlayer is not particularly limited and can be carried out by appropriate methods such as, for example, rotary coating, flexible coating, or roll coating. By doing so, a coating film is formed, and a resist underlayer is formed as the [B] solvent volatilizes.

[0102] Examples of substrates 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, and among these, a silicon substrate is preferred. The substrate may be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, etc. are formed.

[0103] Examples of cases in which a composition for forming a resist underlayer is applied indirectly to a substrate include, for instance, a case in which a composition for forming a resist underlayer is applied on a silicon-containing film formed on the substrate, as described below.

[0104] [Heating Process]

[0105] In the present embodiment, a heating process for heating the coating film formed by the above coating process may be included. The heating of the coating film promotes the formation of a resist underlayer film. More specifically, the heating of the coating film promotes the volatilization of the [B] solvent, etc.

[0106] The heating of the above coating film may be performed under an atmospheric or nitrogen atmosphere. As a lower limit of the heating temperature, 300°C is preferred, 320°C is more preferred, and 350°C is even more preferred. As an upper limit of the above heating temperature, 600°C is preferred, and 500°C is more preferred. As a lower limit of the heating time, 15 seconds is preferred, and 30 seconds is more preferred. As an upper limit of the above time, 1,200 seconds is preferred, and 600 seconds is more preferred.

[0107] In addition, the resist sublayer may be exposed after the above coating process. Plasma may be exposed to the resist sublayer after the above coating process. Ion implantation may be performed on the resist sublayer after the above coating process. When the resist sublayer is exposed, the etching resistance of the resist sublayer is improved. When plasma is exposed to the resist sublayer, the etching resistance of the resist sublayer is improved. When ion implantation is performed on the resist sublayer, the etching resistance of the resist sublayer is improved.

[0108] The radiation used for exposure of the resist underlayer is appropriately selected from electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays, and gamma rays; and particle beams such as electron beams, molecular beams, and ion beams.

[0109] As a method for exposing the resist underlayer to plasma, for example, a direct method can be used by placing the substrate in each gas atmosphere and performing a plasma discharge. As for the plasma exposure conditions, the gas flow rate is typically 50 cc / min or more and 100 cc / min or less, and the power supply is 100 W or more and 1,500 W or less.

[0110] As a lower limit for the plasma exposure time, 10 seconds is preferable, 30 seconds is more preferable, and 1 minute is even more preferable. As an upper limit for the above time, 10 minutes is preferable, 5 minutes is more preferable, and 2 minutes is even more preferable.

[0111] Plasma is generated, for example, under an atmosphere of a mixture of H2 gas and Ar gas. In addition to H2 gas and Ar gas, a carbon-containing gas such as CF4 gas or CH4 gas may be introduced. Also, instead of either or both of H2 gas and Ar gas, at least one of CF4 gas, NF3 gas, CHF3 gas, CO2 gas, CH2F2 gas, CH4 gas, and C4F8 gas may be introduced.

[0112] Ion implantation into the resist sublayer implants a dopant into the resist sublayer. The dopant may be selected from the group including boron, carbon, nitrogen, phosphorus, arsenic, aluminum, and tungsten. The implantation energy used to apply voltage to the dopant may range from about 0.5 keV to 60 keV, depending on the type of dopant used and the desired depth of implantation.

[0113] The lower limit of the average thickness of the formed resist underlayer film is preferably 30 nm, more preferably 50 nm, and even more preferably 100 nm. The upper limit of the average thickness is preferably 3,000 nm, more preferably 2,000 nm, and even more preferably 500 nm. In addition, the method for measuring the average thickness follows the description in the example.

[0114] [Silicon-containing film formation process]

[0115] In this process, a silicon-containing film is formed directly or indirectly on the resist sublayer formed by the coating process or the heating process. Examples of cases where a silicon-containing film is formed indirectly on the resist sublayer include, for instance, a surface modification film of the resist sublayer being formed on the resist sublayer. The surface modification film of the resist sublayer is, for instance, a film having a contact angle with water different from that of the resist sublayer.

[0116] A silicon-containing film can be formed by coating with a composition for forming a silicon-containing film, chemical vapor deposition (CVD), atomic layer deposition (ALD), etc. As a method for forming a silicon-containing film by coating with a composition for forming a silicon-containing film, examples include a method of curing a coated film formed by directly or indirectly coating the silicon-containing film-forming composition onto a resist underlayer film by exposure and / or heating. As commercially available products of the silicon-containing film-forming composition, examples include "NFC SOG01," "NFC SOG04," and "NFC SOG080" (all from JSR Inc.). 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).

[0117] Examples of radiation used in the above exposure include electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays, and γ-rays, as well as particle beams such as electron beams, molecular beams, and ion beams.

[0118] As a lower limit of the temperature when heating the coating film, 90°C is preferred, 150°C is more preferred, and 200°C is even more preferred. As an upper limit of the temperature, 550°C is preferred, 450°C is more preferred, and 300°C is even more preferred.

[0119] As a lower limit for the average thickness of the silicon-containing film, 1 nm is preferred, 10 nm is more preferred, and 20 nm is even more preferred. As an upper limit, 20,000 nm is preferred, 1,000 nm is more preferred, and 100 nm is even more preferred. The average thickness of the silicon-containing film is a value measured using the spectroscopic ellipsometer, just like the average thickness of the resist underlayer.

[0120] [Resist Pattern Formation Process]

[0121] In this process, a resist pattern is formed directly or indirectly on the resist sublayer. Methods for performing this process include, for example, using a resist composition, using a nanoimprint method, or using a self-organizing composition. Examples of cases where a resist pattern is formed indirectly on the resist sublayer include, for example, forming a resist pattern on the silicon-containing film.

[0122] Examples of the above resist compositions include, for instance, a positive or negative type chemical amplification type resist composition containing a radioactive acid generator, a positive type resist composition containing an alkali-soluble resin and a quinone diazide-based photosensitive agent, and a negative type resist composition containing an alkali-soluble resin and a crosslinking agent.

[0123] Examples of coating methods for the resist composition include rotary coating. The temperature and time of pre-baking can be appropriately adjusted depending on the type of resist composition used.

[0124] Next, the resist film formed above is exposed by selective radiation. The radiation used for exposure can be appropriately selected depending on the type of radioactive acid generator used in the resist composition, and examples include visible light, ultraviolet light, far ultraviolet light, electromagnetic waves such as X-rays and γ-rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet light is preferred, KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), F2 excimer laser light (wavelength 157 nm), Kr2 excimer laser light (wavelength 147 nm), ArKr excimer laser light (wavelength 134 nm), or extreme ultraviolet light (wavelength 13.5 nm, etc., hereinafter also referred to as "EUV") is more preferred, and KrF excimer laser light, ArF excimer laser light, or EUV is even more preferred.

[0125] After the above exposure, a post-bake may be performed to improve resolution, pattern profile, developability, etc. The temperature and time of this post-bake can be appropriately determined depending on the type of resist composition used, etc.

[0126] Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be an alkaline development or an organic solvent development. As for the developer, in the case of alkaline development, basic aqueous solutions such as ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide may be used. To these basic aqueous solutions, an appropriate amount of water-soluble organic solvents, such as alcohols like methanol and ethanol, and surfactants may be added. In addition, in the case of organic solvent development, the developer may be various organic solvents exemplified as the [B] solvent of the composition described above.

[0127] After development with the above developer, a predetermined resist pattern is formed by washing and drying.

[0128] [Etching Process]

[0129] In this process, etching is performed using the resist pattern as a mask. The number of etching steps may be one, or multiple, that is, sequential etching may be performed using the pattern obtained by etching as a mask. From the perspective of obtaining a pattern with a better shape, multiple steps are preferred. When performing multiple etching steps, sequential etching is performed, for example, in the order of a silicon-containing film, a resist underlayer film, and a substrate. Examples of etching methods include dry etching and wet etching. From the perspective of making the pattern shape of the substrate better, dry etching is preferred. For this dry etching, a gas plasma, such as oxygen plasma, is used. Through the above etching, a semiconductor substrate having a predetermined pattern is obtained.

[0130] Dry etching can be performed, for example, using 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. Examples include fluorine-based gases such as CHF3, CF4, C2F6, C3F8, SF6, chlorine-based gases such as Cl2, BCl3, oxygen-based gases such as O2, O3, H2O, reducing gases such as H2, NH3, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, HF, HI, HBr, HCl, NO, NH3, BCl3, and inert gases such as He, N2, and Ar. These gases may also be used in combination. When etching a substrate using the pattern of the resist underlayer as a mask, fluorine-based gases are typically used.

[0131] Composition

[0132] The composition contains [A] a polymer and [B] a solvent. As the composition, the composition used in the method for manufacturing the semiconductor substrate can be suitably adopted.

[0133] Examples

[0134] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0135] [Weight Average Molecular Weight (Mw)]

[0136] The Mw of the polymer was measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard, under analysis conditions of flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40℃, using GPC columns of Dosho Co., Ltd. (two “G2000HXL” columns, one “G3000HXL” column, and one “G4000HXL” column), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40℃.

[0137] [Average thickness of the resist sublayer]

[0138] The average thickness of the resist underlayer was determined by measuring the film thickness at 9 randomly spaced points at 5 cm intervals including the center of the resist underlayer using a spectroscopic ellipsometer (JAWOOLLAM “M2000D”) and calculating the average value of the film thicknesses.

[0139] <[A] Synthesis of Polymers>

[0140] A polymer having repeating units represented by the following formulas (A-1) to (A-22) and (x-1) to (x-4) (hereinafter each referred to as “polymer (A-1)”, etc.) was synthesized according to the procedure shown below. In the following formulas, if a number is provided for a repeating unit, it indicates the content ratio (mol%) of that repeating unit.

[0141] [Synthesization Example 1] (Synthesization of polymer (a-1))

[0142] 20.0 g of resorcinol, 25.1 g of 3,4-dihydroxybenzaldehyde, and 120.0 g of 1-butanol were added to a reaction vessel under a nitrogen atmosphere and heated to 80°C to dissolve them. A solution of 10.4 g of p-toluenesulfonic acid monohydrate in 1-butanol (15.0 g) was added to the reaction vessel, and the mixture was heated to 115°C and reacted for 15 hours. After the reaction was finished, the reaction solution was transferred to a separatory funnel, and 200 g of methyl isobutyl ketone and 400 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was concentrated in an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was recovered by suction filtration and washed several times with 100 g of methanol. Afterwards, by drying at 60°C for 12 hours using a vacuum dryer, a polymer (a-1) represented by the following formula (a-1) was obtained. The Mw of the polymer (a-1) was 2,100.

[0143]

[0144] [Synthesization Example 2] (Synthesization of Polymer (A-1))

[0145] In a reaction vessel under a nitrogen atmosphere, 15.0 g of the polymer (a-1), 34.9 g of brominated propargyl, 90 g of methyl isobutyl ketone, and 45.0 g of methanol were added and stirred. Then, 106.9 g of a 25 mass% aqueous solution of tetramethylammonium hydroxide was added, and the mixture was reacted at 50°C for 6 hours. After cooling the reaction mixture to 30°C, 200.0 g of a 5 mass% aqueous solution of oxalic acid was added. After removing the aqueous phase, the obtained organic phase was concentrated in an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was recovered by suction filtration and washed several times with 100 g of methanol. Subsequently, the polymer (A-1) represented by the following formula (A-1) was obtained by drying in a vacuum dryer at 60°C for 12 hours. The Mw of polymer (A-1) was 3,000.

[0146]

[0147] [Synthesization Example 3] (Synthesization of polymer (a-2))

[0148] A polymer (a-2) represented by the following formula (a-2) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 29.2 g of 2,7-dihydroxynaphthalene. The Mw of the polymer (a-2) was 2,500.

[0149]

[0150] [Synthesization Example 4] (Synthesization of Polymer (A-2))

[0151] Except for changing (a-1) 15.0g to (a-2) 18.3g, the polymer (A-2) represented by the following formula (A-2) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-2) was 3,200.

[0152]

[0153] [Synthesization Example 5] (Synthesization of polymer (a-3))

[0154] A polymer (a-3) represented by the following formula (a-3) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 29.1 g of 2,7-dihydroxynaphthalene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,3,4-trihydroxybenzaldehyde. The Mw of the polymer (a-3) was 2,700.

[0155]

[0156] [Synthesization Example 6] (Synthesization of Polymer (A-3))

[0157] Except for changing (a-1) 15.0g to (a-3) 15.8g, the polymer (A-3) represented by the following formula (A-3) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-3) was 3,800.

[0158]

[0159] [Synthesization Example 7] (Synthesization of polymer (a-4))

[0160] A polymer (a-4) represented by the following formula (a-4) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene. The Mw of the polymer (a-4) was 3,000.

[0161]

[0162] [Synthesization Example 8] (Synthesization of Polymer (A-4))

[0163] Except for changing (a-1) 15.0g to (a-4) 24.8g, the polymer (A-4) represented by the following formula (A-4) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-4) was 4,300.

[0164]

[0165] [Synthesization Example 9] (Synthesization of polymer (a-5))

[0166] A polymer (a-5) represented by the following formula (a-5) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,3,4-trihydroxybenzaldehyde. The Mw of the polymer (a-5) was 2,500.

[0167]

[0168] [Synthesization Example 10] (Synthesization of Polymer (A-5))

[0169] Except for changing (a-1) 15.0g to (a-5) 20.8g, the polymer (A-5) represented by the following formula (A-5) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-5) was 3,600.

[0170]

[0171] [Synthesization Example 11] (Synthesization of polymer (a-6))

[0172] A polymer (a-6) represented by the following formula (a-6) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,4,6-trihydroxybenzaldehyde. The Mw of the polymer (a-6) was 2,300.

[0173]

[0174] [Synthesization Example 12] (Synthesization of Polymer (A-6))

[0175] Except for changing (a-1) 15.0g to (a-6) 20.8g, the polymer (A-6) represented by the following formula (A-6) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-6) was 3,300.

[0176]

[0177] [Synthesization Example 13] (Synthesization of polymer (a-7))

[0178] A polymer (a-7) represented by the following formula (a-7) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 3,4,5-trihydroxybenzaldehyde. The Mw of the polymer (a-7) was 2,600.

[0179]

[0180] [Synthesizing Example 14] (Synthesization of Polymer (A-7))

[0181] Except for changing (a-1) 15.0g to (a-7) 20.8g, the polymer (A-7) represented by the following formula (A-7) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-7) was 3,700.

[0182]

[0183] [Synthesizing Example 15] (Synthesization of Polymer (a-8))

[0184] A polymer (a-8) represented by the following formula (a-8) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,4,5-trihydroxybenzaldehyde. The Mw of the polymer (a-8) was 2,300.

[0185]

[0186] [Synthesization Example 16] (Synthesization of Polymer (A-8))

[0187] Except for changing (a-1) 15.0g to (a-8) 20.8g, the polymer (A-8) represented by the following formula (A-8) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-8) was 3,400.

[0188]

[0189] [Synthesizing Example 17] (Synthesization of Polymer (a-9))

[0190] A polymer (a-9) represented by the following formula (a-9) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 31.8 g of 1-hydroxypyrene and 9.9 g of 2,2'-dinaphthyl ether. The Mw of the polymer (a-9) was 2,200.

[0191]

[0192] [Synthesizing Example 18] (Synthesization of Polymer (A-9))

[0193] Except for changing (a-1) 15.0g to (a-9) 26.9g, the polymer (A-9) represented by the following formula (A-9) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-9) was 3,200.

[0194]

[0195] [Synthesization Example 19] (Synthesization of polymer (a-10))

[0196] A polymer (a-10) represented by the following formula (a-10) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 31.8 g of 1-hydroxypyrene and 9.9 g of 2,2'-dinaphthyl ether, and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,4,6-trihydroxybenzaldehyde. The Mw of the polymer (a-10) was 2,400.

[0197]

[0198] [Synthesizing Example 20] (Synthesization of Polymer (A-10))

[0199] Except for changing (a-1) 15.0g to (a-10) 22.3g, the polymer (A-10) represented by the following formula (A-10) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-10) was 3,500.

[0200]

[0201] [Synthesization Example 21] (Synthesization of polymer (a-11))

[0202] A polymer (a-11) represented by the following formula (a-11) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 31.8 g of 1-hydroxypyrene and 9.9 g of 2,2'-dinaphthyl ether, and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,3,4-trihydroxybenzaldehyde. The Mw of the polymer (a-11) was 2,400.

[0203]

[0204] [Synthesizing Example 22] (Synthesization of Polymer (A-11))

[0205] Except for changing (a-1) 15.0g to (a-11) 22.3g, the polymer (A-11) represented by the following formula (A-11) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-11) was 3,400.

[0206]

[0207] [Synthesization Example 23] (Synthesization of polymer (a-12))

[0208] A polymer (a-12) represented by the following formula (a-12) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 31.8 g of 1-hydroxypyrene and 6.2 g of diphenyl ether, and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,3,4-trihydroxybenzaldehyde. The Mw of the polymer (a-12) was 2,600.

[0209]

[0210] [Synthesization Example 24] (Synthesization of Polymer (A-12))

[0211] Except for changing (a-1) 15.0g to (a-12) 21.1g, the polymer (A-12) represented by the following formula (A-12) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-12) was 3,600.

[0212]

[0213] [Synthesizing Example 25] (Synthesization of Polymer (a-13))

[0214] A polymer (a-13) represented by the following formula (a-13) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 31.8 g of 1-hydroxypyrene and 6.2 g of diphenyl ether. The Mw of the polymer (a-13) was 2,900.

[0215]

[0216] [Synthesization Example 26] (Synthesization of Polymer (A-13))

[0217] Except for changing (a-1) 15.0g to (a-13) 25.4g, the polymer (A-13) represented by the following formula (A-13) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-13) was 4,100.

[0218]

[0219] [Synthesizing Example 27] (Synthesization of Polymer (A-14))

[0220] Except for changing (a-1) 15.0 g to (a-4) 24.6 g and 34.9 g of brominated propargyl to 34.9 g of bromoacetonitrile, the same as in Synthesis Example 2 was performed to obtain a polymer (A-14) represented by the following formula (A-14). The Mw of the polymer (A-14) was 4,500.

[0221]

[0222] [Synthesizing Example 28] (Synthesization of Polymer (a-14))

[0223] A polymer (a-14) represented by the following formula (a-14) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 63.9 g of 9,9'-bis(4-hydroxyphenyl)fluorene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 28.1 g of 2,3,4-trihydroxybenzaldehyde. The Mw of the polymer (a-14) was 3,400.

[0224]

[0225] [Synthesizing Example 29] (Synthesization of Polymer (A-15))

[0226] Except for changing (a-1) 15.0g to (a-14) 23.6g, the polymer (A-15) represented by the following formula (A-15) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-15) was 5,000.

[0227]

[0228] [Synthesization Example 30] (Synthesization of Polymer (A-16))

[0229] Except for changing (a-1) 15.0 g to (a-5) 20.8 g and 34.9 g of brominated propargyl to 39.0 g of 4-bromo-1-butine, the same as in Synthesis Example 2 was performed to obtain a polymer (A-16) represented by the following formula (A-16). The Mw of the polymer (A-16) was 4,100.

[0230]

[0231] [Synthesization Example 31] (Synthesization of Polymer (A-17))

[0232] Except for changing (a-1) 15.0 g to (a-2) 18.1 g and 34.9 g of brominated propargyl to 35.2 g of bromoacetonitrile, the polymer (A-17) represented by the following formula (A-17) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-17) was 3,300.

[0233]

[0234] [Synthesization Example 32] (Synthesization of polymer (a-15))

[0235] A polymer (a-15) represented by the following formula (a-15) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 33.4 g of 3,4-dihydroxy-5-nitrobenzaldehyde. The Mw of the polymer (a-15) was 2,700.

[0236]

[0237] [Synthesizing Example 33] (Synthesization of Polymer (A-18))

[0238] Except for changing (a-1) 15.0g to (a-15) 28.1g, the polymer (A-18) represented by the following formula (A-18) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-18) was 3,800.

[0239]

[0240] [Synthesizing Example 34] (Synthesization of Polymer (A-19))

[0241] Except for changing (a-1) 15.0 g to (a-15) 28.1 g and 34.9 g of brominated propargyl to 35.2 g of bromoacetonitrile, the polymer (A-19) represented by the following formula (A-19) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-19) was 3,900.

[0242]

[0243] [Synthesization Example 35] (Synthesization of polymer (a-16))

[0244] A polymer (a-16) represented by the following formula (a-16) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 23.0 g of anhydrous phloroglucinol. The Mw of the polymer (a-16) was 2,400.

[0245]

[0246] [Synthesization Example 36] (Synthesization of Polymer (A-20))

[0247] Except for changing (a-1) 15.0g to (a-16) 13.1g, the polymer (A-20) represented by the following formula (A-20) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-20) was 3,500.

[0248]

[0249] [Synthesizing Example 37] (Synthesization of Polymer (A-21))

[0250] Except for changing (a-1) 15.0 g to (a-16) 13.1 g and 34.9 g of brominated propargyl to 35.2 g of bromoacetonitrile, the polymer (A-21) represented by the following formula (A-21) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (A-21) was 3,600.

[0251]

[0252] [Synthesizing Example 38] (Synthesization of Polymer (A-22))

[0253] Except for changing (a-1) 15.0 g to (a-16) 13.1 g and 34.9 g of brominated propargyl to 57.3 g of 1-(bromomethyl)-4-ethynylbenzene, the polymer (A-22) represented by the following formula (A-22) was obtained in the same manner as in Synthesis Example 2. The Mw of the polymer (A-22) was 6,100.

[0254]

[0255] [Comparative Synthesis Example 1] (Synthesis of polymer (x-1))

[0256] 250.0 g of m-cresol, 125.0 g of 37 mass% formalin, and 2 g of oxalic anhydride were added to a reaction vessel under a nitrogen atmosphere, and the mixture was reacted at 100°C for 3 hours and at 180°C for 1 hour, after which unreacted monomers were removed under reduced pressure to obtain a polymer (x-1) represented by the following formula (x-1). The Mw of the obtained polymer (x-1) was 11,000.

[0257]

[0258] [Comparative Synthesis Example 2] (Synthesis of polymer (x-2))

[0259] Polymer (x-2) is identical to polymer (a-4), and polymer (x-2) was obtained in the same manner as in Synthesis Example 7.

[0260] [Comparative Synthesis Example 3] (Synthesis of polymer (x-3))

[0261] A polymer (x-3) represented by the following formula (x-3) was obtained in the same manner as Synthesis Example 1, except that 20.0 g of resorcinol was replaced with 39.8 g of 1-hydroxypyrene and 25.1 g of 3,4-dihydroxybenzaldehyde was replaced with 27.7 g of vanillin. The Mw of the polymer (x-3) was 3,400.

[0262]

[0263] [Comparative Synthesis Example 4] (Synthesis of polymer (x'-4))

[0264] In a reaction vessel under a nitrogen atmosphere, 29.1 g of 2,7-dihydroxynaphthalene, 14.8 g of 37 mass% formaldehyde solution, and 87.3 g of methyl isobutyl ketone were added and dissolved. 1.0 g of p-toluenesulfonic acid monohydrate was added to the reaction vessel, heated to 85°C, and reacted for 4 hours. After the reaction was finished, the reaction solution was transferred to a separatory funnel, and 200 g of methyl isobutyl ketone and 400 g of water were added to wash the organic phase. After separating the aqueous phase, the obtained organic phase was concentrated in an evaporator, and the residue was added dropwise to 500 g of methanol to obtain a precipitate. The precipitate was recovered by suction filtration and washed several times with 100 g of methanol. Afterwards, by drying at 60°C for 12 hours using a vacuum dryer, a polymer (x'-4) represented by the following formula (x'-4) was obtained. The Mw of the polymer (x'-4) was 3,400.

[0265]

[0266] [Comparative Synthesis Example 5] (Synthesis of polymer (x-4))

[0267] Except for changing (a-1) 15.0g to (x'-4) 16.8g, the polymer (x-4) represented by the following formula (x-4) was obtained in the same manner as Synthesis Example 2. The Mw of the polymer (x-4) was 4,500.

[0268]

[0269] <Preparation of Composition>

[0270] [A] Polymer, [B] Solvent, [C] Acid-generating agent, and [D] Crosslinking agent used in the preparation of the composition are described below.

[0271] [[A] Polymer]

[0272] Examples: Compounds (A-1) to (A-22) synthesized above

[0273] Comparative Example: The above-synthesized polymers (x-1) to (x-4)

[0274] [[B] Solvent]

[0275] B-1: Propylene glycol monomethyl ether acetate

[0276] B-2: Cyclohexanone

[0277] [[C] Acid-generating agent]

[0278] C-1: Bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate (compound represented by the following formula (C-1))

[0279]

[0280] [[D] Crosslinking agent]

[0281] D-1: Compound represented by the following formula (D-1)

[0282]

[0283] D-2: Compounds represented by the following formula (D-2)

[0284]

[0285] [Example 1-1]

[0286] [A] 10 parts by mass of (A-1) as a polymer was dissolved in [B] 90 parts by mass of (B-1) as a solvent. The obtained solution was filtered through a polytetrafluoroethylene (PTFE) membrane filter with a pore diameter of 0.45 μm to prepare composition (J-1).

[0287] [Examples 1-2 to 1-27 and Comparative Examples 1-1 to 1-4]

[0288] Compositions (J-2) to (J-27) and (CJ-1) to (CJ-4) were prepared in the same manner as in Example 1, except that each component of the type and content shown in Table 1 below was used. In Table 1, the “-” in the columns of “[A] Polymer,” “[C] Acid-generating agent,” and “[D] Crosslinking agent” indicates that the corresponding component was not used.

[0289]

[0290] <Evaluation>

[0291] Using the composition obtained above, etching resistance, heat resistance, bending resistance, and the content ratio of hydrogen atoms and carbon atoms in the coating film of the composition were evaluated by the following method. The evaluation results are shown in Table 2 below.

[0292] [Etching Resistance]

[0293] The above-described composition was coated onto a silicon wafer (substrate) by a spin coating method using a spin coater (Tokyo Electron Inc.’s “CLEAN TRACK ACT12”). Subsequently, by heating at 350°C for 60 seconds under an atmospheric environment and then cooling at 23°C for 60 seconds, a film with an average thickness of 200 nm was formed, thereby obtaining a substrate equipped with a film having a resist underlayer formed on the substrate. The film on the substrate equipped with the film obtained above was processed using an etching device (Tokyo Electron Co., Ltd.’s “TACTRAS”) under conditions of CF4 / Ar=110 / 440 sccm, PRESS.=30 MT, HF RF (high-frequency power for plasma generation)=500 W, LF RF (high-frequency power for bias)=3000 W, DCS=-150 V, RDC (gas center flow rate ratio)=50%, and 30 seconds, and the etching rate (nm / min) was calculated from the average thickness of the film before and after processing. Subsequently, the ratio to Comparative Example 1 was calculated based on the etching rate of Comparative Example 1, and this ratio was used as a measure of etching resistance. Etching resistance was evaluated as “A” (extremely good) when the ratio was 0.90 or less, “B” (good) when it exceeded 0.90 and was less than 0.92, and “C” (poor) when it was 0.92 or more. In addition, “-” in Table 2 indicates the evaluation criteria for etching resistance.

[0294] [Heat resistance]

[0295] The above-prepared composition was coated onto a silicon wafer (substrate) by a spin coating method using a spin coater (Tokyo Electron Inc.’s “CLEAN TRACK ACT12”). Subsequently, a film with an average thickness of 200 nm was formed by heating at 200°C for 60 seconds under an atmospheric environment and then cooling at 23°C for 60 seconds, thereby obtaining a film-equipped substrate with a film formed on the substrate. Powder was recovered by etching the film of the obtained film-equipped substrate, and the recovered powder was placed in a container used for measurement by a TG-DTA device (NETZSCH’s “TG-DTA2000SR”), and the mass before heating was measured. Subsequently, using the TG-DTA device, the mixture was heated to 400°C at a heating rate of 10°C / min under a nitrogen atmosphere, and the mass of the powder was measured when it reached 400°C. Then, the mass loss rate (%) was measured using the following formula, and this mass loss rate was used as a measure of heat resistance.

[0296] M L ={(m1-m2) / m1}×100

[0297] Here, among the above formulas, M L is the mass reduction rate (%), m1 is the mass before heating (mg), and m2 is the mass at 400℃ (mg).

[0298] Heat resistance is good, as the smaller the mass loss rate of the powder sample, the less sublimation or decomposition product of the membrane is generated when heating the membrane. In other words, a smaller mass loss rate indicates higher heat resistance. Heat resistance was evaluated as "A" (extremely good) when the mass loss rate is less than 5%, "B" (good) when it is 5% or more but less than 10%, and "C" (poor) when it is 10% or more.

[0299] [Bending resistance]

[0300] The above-prepared composition was coated by a spin coating method using a spin coater (Tokyo Electron Inc.’s “CLEAN TRACK ACT12”) on a silicon substrate having a silicon dioxide film with an average thickness of 500 nm. Subsequently, a film-equipped substrate having a resist underlayer film with an average thickness of 200 nm was obtained by heating at 350°C for 60 seconds under an atmospheric atmosphere and then cooling at 23°C for 60 seconds. A silicon-containing film-forming composition (JSR Inc.’s “NFC SOG080”) was coated by a spin coating method on the obtained film-equipped substrate, then heated at 200°C for 60 seconds under an atmospheric atmosphere and then heated at 300°C for 60 seconds to form a silicon-containing film with an average thickness of 50 nm. An ArF resist composition ("AR1682J" of JSR Inc.) was coated onto the silicon-containing film by a rotary coating method, and heated (fired) at 130°C for 60 seconds under an atmospheric environment to form a resist film with an average thickness of 200 nm. A resist film was exposed using an ArF excimer laser exposure device (lens numerical aperture 0.78, exposure wavelength 193 nm) with varying exposure amounts through a one-to-one line and space mask pattern with a target size of 100 nm, then heated (sintered) at 130°C for 60 seconds under an atmospheric environment, developed at 25°C for 1 minute using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH), washed with water, and dried to obtain a substrate having a line and space resist pattern of 200 nm pitch with a line pattern width of 30 nm to 100 nm.

[0301] Using the above resist pattern as a mask, the silicon-containing film was etched using the above etching device under conditions of CF4=200 sccm, PRESS.=85 mT, HF RF (high-frequency power for plasma generation)=500 W, LF RF (high-frequency power for bias)=0 W, DCS=-150 V, and RDC (gas center flow rate ratio)=50%, thereby obtaining a substrate with a pattern formed on the silicon-containing film. Subsequently, using the above silicon-containing film pattern as a mask, the resist lower layer was etched using the above etching device under conditions of O2=400 sccm, PRESS.=25 mT, HF RF (high-frequency power for plasma generation)=400 W, LF RF (high-frequency power for bias)=0 W, DCS=0 V, and RDC (gas center flow rate ratio)=50%, thereby obtaining a substrate with a pattern formed on the resist lower layer. Using the above resist lower layer pattern as a mask, the silicon dioxide film was etched using the above etching device under the conditions of CF4=180 sccm, Ar=360 sccm, PRESS.=150 mT, HF RF (high-frequency power for plasma generation)=1,000 W, LF RF (high-frequency power for bias)=1,000 W, DCS=-150 V, RDC (gas center flow rate ratio)=50%, and 60 seconds, thereby obtaining a substrate with a pattern formed on the silicon dioxide film.

[0302] After that, regarding the substrate on which a pattern is formed on the silicon dioxide film, an image magnified 250,000 times using a scanning electron microscope ("CG-4000" of Hitachi High Technologies Inc.) is obtained for each line width of the resist sublayer pattern, and by performing image processing, as shown in FIG. 1, the line width direction positions (Xn) (n=1 to 10) measured at 10 locations at 100 nm intervals for the horizontal side (3a) of the resist sublayer pattern (3) (line pattern) with a length of 1,000 nm are calculated, and the standard deviation calculated from the average value position (Xa) of these line width direction positions is 3 times the value of 3 sigma, which is set as LER (line edge roughness). LER, which indicates the degree of bending of the resist sublayer pattern, increases as the line width of the resist sublayer pattern becomes thinner. Bending resistance was evaluated as “A” (good) when the line width of the film pattern with an LER of 5.5 nm is less than 40.0 nm, “B” (slightly good) when it is 40.0 nm or more and less than 45.0 nm, and “C” (poor) when it is 45.0 nm or more. In addition, the bending state of the film pattern shown in Fig. 1 is described as exaggerated compared to the actual state.

[0303] [Content ratio of hydrogen atoms and carbon atoms in the coating film of the composition]

[0304] The above-prepared compositions (J-1) to (J-20) and (CJ-1) to (CJ-4) were coated onto a silicon wafer (substrate) by a spin coater ("CLEAN TRACK ACT12" of Tokyo Electron Co., Ltd.) using a rotational coating method. Subsequently, by heating at 400°C for 90 seconds under an atmospheric environment and then cooling at 23°C for 60 seconds, a film with an average thickness of 200 nm was formed, thereby obtaining a film-equipped substrate having a resist underlayer formed on the substrate. Powder was recovered by etching the film of the obtained film-equipped substrate, and the content ratio R' of hydrogen atoms, carbon atoms, and nitrogen atoms in the coating film was determined using a CHN simultaneous analysis device ("MICRO CORDER JM10" of J Science).H , R' C , R' N (wt%) was measured. Oxygen atom content ratio R' O (wt%) was calculated by the following formula.

[0305] R' O =100-R' H -R' C -R' N

[0306] Also, the ratio of hydrogen atoms to carbon atoms R according to the following formula H , R C (atm%) was calculated.

[0307] R H =(R' H ) / {(R' H )+(R' C / 12)+(R' O / 16)+(R' N / 14)}×100

[0308] R C =(R' C / 12) / {(R' H )+(R' C / 12)+(R' O / 16)+(R' N / 14)}×100

[0309]

[0310] As can be seen from the results in Table 2, the resist underlayer formed with the composition of the example had excellent etching resistance, heat resistance, and bending resistance compared to the resist underlayer formed with the composition of the comparative example. Industrial applicability

[0311] According to the method for manufacturing a semiconductor substrate of the present invention, a well-patterned substrate can be obtained. The composition of the present invention can form a resist underlayer film with excellent etching resistance, heat resistance, and bending resistance. Therefore, these can be suitably used for the manufacture of semiconductor devices, etc., which are expected to undergo further miniaturization. Explanation of the symbols

[0312] 3: Resist sublayer pattern 3a: Transverse side of the resist sublayer pattern

Claims

Claim 1 A method for manufacturing a semiconductor substrate comprising: a process of coating a composition for forming a resist sublayer film directly or indirectly onto a substrate; a process of forming a resist pattern directly or indirectly on the resist sublayer film formed by the coating process; and a process of performing etching using the resist pattern as a mask, wherein the composition for forming a resist sublayer film comprises a polymer having repeating units represented by the following formula (1) and a solvent. (In formula (1), Ar 1 It is a divalent group having an aromatic ring with 5 to 40 reduction waters, and does not contain an imide group. R 0 Silver is a monovalent group having an aromatic ring of 5 to 40 reduced waters, and has at least one group selected from the group consisting of the group represented by the following formula (2-1) and the group represented by the following formula (2-2). (In equations (2-1) and (2-2), R 7 Each is independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.) Claim 2 A method for manufacturing a semiconductor substrate according to claim 1, further comprising a process of forming a silicon-containing film directly or indirectly on the resist underlayer film before forming the resist pattern. Claim 3 A composition containing a polymer having repeating units represented by the following formula (1) and a solvent. (In formula (1), Ar 1 It is a divalent group having an aromatic ring with 5 to 40 reduction waters, and does not contain an imide group. R 0 Silver is a monovalent group having an aromatic ring of 5 to 40 reduced waters, and has at least one group selected from the group consisting of the group represented by the following formula (2-1) and the group represented by the following formula (2-2). (In equations (2-1) and (2-2), R 7 Each is independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a bond with a carbon atom in an aromatic ring.) Claim 4 In paragraph 3, the above R 0 A composition having at least two groups selected from the group consisting of a group represented by formula (2-1) and a group represented by formula (2-2), wherein the group is a monovalent group having 5 to 40 aromatic rings of reduced water. Claim 5 In paragraph 3, the above Ar 1 A composition having at least one group selected from the group consisting of the group represented by the above formula (2-1) and the group represented by the above formula (2-2). Claim 6 In paragraph 3, 4, or 5, the above R 0 This composition has a group represented by the above formula (2-1), and the group is represented by the following formula (2-1-1). Claim 7 In paragraph 3, 4, or 5, the above Ar 1 A composition in which the aromatic ring is at least one aromatic hydrocarbon ring selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, a fluorene ring, a perylene ring, and a coronene ring. Claim 8 In paragraph 3, 4, or 5, the above R 0 A composition in which the aromatic ring is at least one aromatic hydrocarbon ring selected from the group consisting of a benzene ring, a naphthalene ring, anthracene ring, a phenalene ring, a phenanthrene ring, a pyrene ring, a fluorene ring, a perylene ring, and a coronene ring. Claim 9 In paragraph 3, 4, or 5, the above R 0 A composition in which the aromatic ring is a benzene ring. Claim 10 A composition according to claim 3, 4, or 5, wherein the content of hydrogen atoms in the coating film of the composition after heating the coating film at 400°C for 90 seconds is 26.0 atm% or less. Claim 11 A composition according to claim 3, 4, or 5, wherein the carbon atom content ratio in the coating film of the composition after heating the coating film of the composition at 400°C for 90 seconds is 53.0 atm% or more. Claim 12 A composition for forming a resist underlayer film in paragraph 3, 4, or 5.

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