Silicon-containing composition and method for producing semiconductor substrate

Abstract

Provided are: a silicon-containing composition capable of forming silicon-containing films with which it is possible to form resist patterns having excellent rectangular cross-sectional shapes; and a method for producing a semiconductor substrate. The silicon-containing composition comprises a polysiloxane having a first structural unit represented by formula (1) and a solvent. (In formula (1), X is an alkali-dissociable group, a is an integer of 1-3, when a is 2 or 3, then the X moieties are the same or different, R1 is a monovalent organic group having 1-20 carbon atoms or is a hydroxy group or a halogen atom, b is an integer of 0-2, and when b is 2, then the two R1 moieties are the same or different, with the proviso that a+b is 3 or less.)

Description

[Technical Field]

[0001] The present invention relates to silicon-containing compositions and methods for producing semiconductor substrates. [Background technology]

[0002] For pattern formation in the manufacture of semiconductor substrates, for example, a multilayer resist process is used in which a resist film laminated on a substrate via an organic underlayer film, a silicon-containing film, etc. is exposed and developed to obtain a resist pattern, which is then used as a mask to perform etching to form a patterned substrate (see WO 2012 / 039337). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 039337 Summary of the Invention [Problem to be solved by the invention]

[0004] In further developing the multilayer resist process, it has been found that the shape (rectangularity) of the resist pattern after alkaline development of the resist film may be impaired.

[0005] An object of the present invention is to provide a silicon-containing composition capable of forming a silicon-containing film capable of forming a resist pattern having an excellent cross-sectional rectangular shape, and a method for producing a semiconductor substrate. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the present inventors have found that the above object can be achieved by employing the following configuration, and have thus completed the present invention.

[0007] In one embodiment, the present invention provides A polysiloxane having a first structural unit represented by the following formula (1): Solvent and The present invention relates to a silicon-containing composition comprising: [ka] (In the above formula (1), X is an alkali-dissociable group. a is an integer of 1 to 3. When a is 2 or more, multiple Xs may be the same or different. R 1 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R 1 are the same or different, provided that a+b is 3 or less.)

[0008] The silicon-containing composition contains a polysiloxane having an alkali-dissociable group in the first structural unit. Thus, when a silicon-containing film is formed using the silicon-containing composition, a resist pattern with excellent cross-sectional rectangularity can be formed (hereinafter, the rectangularity of the cross-sectional shape of the resist pattern is also referred to as "pattern rectangularity"). While the reason for this is unclear, it is presumed as follows: During alkaline development of the exposed resist film, the alkali-dissociable group of the polysiloxane dissociates in the exposed areas, increasing the polarity of the polysiloxane and increasing the affinity or permeability of the developer to the silicon-containing film. As a result, the generation of resist film residue near the interface between the resist film and the silicon-containing film is suppressed, resulting in good pattern rectangularity. Meanwhile, in the unexposed areas, the hydrophobicity of the silicon-containing film is maintained, maintaining adhesion to the overlying resist film. As a result, the collapse of the resist pattern is suppressed, resulting in good pattern rectangularity. Thus, it is presumed that a silicon-containing film formed from the silicon-containing composition can exhibit excellent pattern rectangularity due to the synergistic effect of suppressing residue in exposed areas and suppressing pattern collapse in unexposed areas.

[0009] In this specification, "polysiloxane" refers to a compound containing a siloxane bond (-Si-O-Si-). Furthermore, "alkali-dissociable group" refers to a group containing a group that substitutes a hydrogen atom of a carboxy group or an alcoholic hydroxy group, and that dissociates in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C for 1 minute. "Organic group" refers to a group containing at least one carbon atom, and "number of carbon atoms" refers to the number of carbon atoms that constitute the group.

[0010] In another embodiment, the present invention provides a method for forming a silicon-containing film by directly or indirectly applying the silicon-containing composition to a substrate; a step of applying a resist film-forming composition directly or indirectly to the silicon-containing film to form a resist film; exposing the resist film to radiation; developing the exposed resist film to form a resist pattern; The present invention relates to a method for manufacturing a semiconductor substrate, including:

[0011] In this manufacturing method, the silicon-containing composition is used to form a silicon-containing film as an underlayer of a resist film, and a resist pattern with excellent cross-sectional rectangularity can be formed, thereby enabling efficient manufacturing of high-quality semiconductor substrates. DETAILED DESCRIPTION OF THE INVENTION

[0012] The silicon-containing composition and the method for producing a semiconductor substrate according to the embodiments of the present invention will be described in detail below.

[0013] <Silicon-containing composition> The silicon-containing composition according to this embodiment contains a polysiloxane having an alkali-dissociable group incorporated therein and a solvent. The composition may contain other optional components (hereinafter simply referred to as "optional components") within the scope of the present invention.

[0014] By containing the above-mentioned polysiloxane and a solvent, the silicon-containing composition can form a resist pattern with excellent cross-sectional rectangularity when forming a resist pattern on the silicon-containing film by alkaline development. Because of this effect, the silicon-containing composition can be suitably used as a composition for forming a silicon-containing film (i.e., a silicon-containing film-forming composition).

[0015] The silicon-containing composition is suitable for use in forming an underlayer film of a resist film that undergoes alkaline development. In this case, after forming a resist film and exposing it, the exposed portion of the resist film is dissolved during alkaline development, exposing the silicon-containing film that is the underlayer film of the resist film. The silicon-containing film has increased affinity with the developer due to dissociation of the alkali-dissociable group caused by alkaline development, which induces sufficient dissolution of the resist film near the interface between the resist film and the silicon-containing film, thereby forming a resist pattern with excellent cross-sectional rectangularity. Meanwhile, in the unexposed portion, the hydrophobicity of the silicon-containing film is maintained, maintaining the adhesion between the resist film and the silicon-containing film, which can prevent the resist pattern from collapsing, thereby contributing to improving the rectangularity of the pattern.

[0016] The resist film to be developed in an alkali environment is preferably a positive resist film, and more preferably a positive resist film for exposure with ArF excimer laser light (for ArF exposure) or extreme ultraviolet (EUV) light (for EUV exposure). In other words, the silicon-containing composition is suitable for forming an underlayer film of a resist film to be developed in an alkali environment for ArF exposure or EUV exposure.

[0017] [Polysiloxane] The silicon-containing composition contains a polysiloxane having a predetermined first structural unit. The silicon-containing composition may contain one or more types of polysiloxane. The polysiloxane may contain structural units other than the first structural unit (hereinafter simply referred to as "other structural units") within the range that does not impair the effects of the present invention. Each structural unit contained in the polysiloxane will be described below.

[0018] (first structural unit) The first structural unit is represented by the following formula (1): The polysiloxane may have one or more types of first structural units: The first structural unit has an alkali-dissociable group represented by X in the following formula (1), thereby making it possible to form a silicon-containing film that can impart excellent pattern rectangularity to the resist pattern.

[0019] [ka]

[0020] In the above formula (1), X is an alkali-dissociable group. a is an integer of 1 to 3. When a is 2 or more, multiple Xs may be the same or different. R 1 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R 1 are the same or different, provided that a+b is 3 or less.

[0021] In the above formula (1), the alkali-dissociable group represented by X is not particularly limited as long as it is dissociated by an alkali, but examples thereof include groups in which an ester bond is incorporated between two carbon atoms in a monovalent organic group having 1 to 30 carbon atoms.

[0022] In the above formula (1), examples of the monovalent organic group having 1 to 30 carbon atoms in the alkali dissociable group represented by X include monovalent hydrocarbon groups having 1 to 30 carbon atoms, groups containing a divalent heteroatom-containing linking group between the carbon-carbon bond of this hydrocarbon group (hereinafter also referred to as "group (α)"), groups in which some or all of the hydrogen atoms in the above hydrocarbon group or the above group (α) have been substituted with monovalent heteroatom-containing substituents (hereinafter also referred to as "group (β)"), and groups in which the above hydrocarbon group, the above group (α) or the above group (β) are combined with a divalent heteroatom-containing linking group (hereinafter also referred to as "group (γ)").

[0023] As used herein, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" may be a saturated or unsaturated hydrocarbon group. A "linear hydrocarbon group" refers to a hydrocarbon group that does not contain a cyclic structure and is composed only of a linear structure, and includes both linear hydrocarbon groups and branched hydrocarbon groups. An "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic structure as a ring structure and does not contain an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it does not have to be composed solely of an alicyclic structure, and may contain a linear structure as part of it. An "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not have to be composed solely of an aromatic ring structure, and may contain a linear structure or an alicyclic structure as part of it.

[0024] Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms include a monovalent chain hydrocarbon group having 1 to 30 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms.

[0025] Examples of the monovalent chain hydrocarbon group having 1 to 30 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, iso-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 30 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group; polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group and a tetracyclododecyl group; monocyclic alicyclic unsaturated hydrocarbon groups such as a cyclopentenyl group and a cyclohexenyl group; and polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group, a tricyclodecenyl group and a tetracyclododecenyl group.

[0027] Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthryl groups, and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthrylmethyl groups.

[0028] Examples of heteroatoms constituting the divalent heteroatom-containing linking group and the monovalent heteroatom-containing substituent include oxygen, nitrogen, sulfur, phosphorus, silicon, and halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0029] Examples of divalent heteroatom-containing linking groups include -O-, -C(=O)-, -S-, -C(=S)-, -NR'-, -SO2-, and groups formed by combining two or more of these. R' is a hydrogen atom or a monovalent hydrocarbon group.

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

[0031] a is preferably 1 or 2, and more preferably 1.

[0032] R 1 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (I) include the same groups having 1 to 20 carbon atoms as those exemplified as the monovalent organic group having 1 to 30 carbon atoms for X above.

[0033] R 1 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0034] R 1As the alkyl group, a monovalent chain hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent group in which some or all of the hydrogen atoms of a monovalent hydrocarbon group have been substituted with a monovalent heteroatom-containing substituent is preferred, an alkyl group or an aryl group is more preferred, and a methyl group, an ethyl group, or a phenyl group is even more preferred.

[0035] b is preferably 0 or 1, and more preferably 0.

[0036] X in the above formula (1) is preferably represented by the following formula (1-1) (excluding the cases represented by the following formulas (1-2) and (1-3)), the following formula (1-2) (excluding the case represented by the following formula (1-3)), the following formula (1-3) or the following formula (1-4).

[0037] [ka]

[0038] In the above formula (1-1), L 1 is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R 2 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and R 4 is a monovalent hydrocarbon group having 1 to 10 carbon atoms or a monovalent heteroatom-containing group having 1 to 10 carbon atoms, or R 3 and R 4 represent a ring structure having 3 to 20 ring members formed by bonding together with the carbon atoms to which they are bonded.

[0039] [ka]

[0040] In the above formula (1-2), L 2 is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R 5is a monovalent organic group having 1 to 10 carbon atoms.

[0041] [ka]

[0042] In the above formula (1-3), L 3 is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R 6 is a monovalent organic group having 1 to 10 carbon atoms.

[0043] [ka]

[0044] In the above formula (1-4), L 4 is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R 7 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. 8 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and R 9 is a monovalent hydrocarbon group having 1 to 10 carbon atoms or a monovalent heteroatom-containing group having 1 to 10 carbon atoms, or R 8 and R 9 represent a ring structure having 3 to 20 ring members formed by bonding together with the carbon atoms to which they are bonded.

[0045] In the above formulas (1-1), (1-2), (1-3) and (1-4), L 1 , L 2 , L 3 and L 4 Examples of the divalent linking group represented by the formula (1) include divalent organic groups having 1 to 10 carbon atoms. Examples of the divalent organic group having 1 to 10 carbon atoms include groups in which one hydrogen atom has been removed from a monovalent organic group having 1 to 10 carbon atoms, among the groups exemplified as the monovalent organic group having 1 to 30 carbon atoms for X in the formula (1) above.

[0046] Among them, the above L 1 , L2 , L 3 and L 4 As the heteroatom-containing substituent, a divalent hydrocarbon group having 1 to 10 carbon atoms or a group containing a divalent heteroatom-containing group between the carbon-carbon bond of the divalent hydrocarbon group having 1 to 10 carbon atoms is preferred, an alkylene group, an alkenylene group, or a group containing -S- between the carbon-carbon bond of the alkylene group is more preferred, and an alkylene group is even more preferred. Some or all of the hydrogen atoms in these groups may be substituted with a monovalent heteroatom-containing substituent. As the monovalent heteroatom-containing substituent, the monovalent heteroatom-containing substituent for X above can be suitably used.

[0047] In the above formulas (1-1) and (1-4), R 2 , R 3 , R 4 , R 7 , R 8 and R 9 As the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I), a monovalent hydrocarbon group having 1 to 10 carbon atoms can be suitably used from among the monovalent hydrocarbon groups having 1 to 30 carbon atoms represented by X above.

[0048] In the above formulas (1-1) and (1-4), R 4 and R 9 As the monovalent heteroatom-containing group having 1 to 10 carbon atoms represented by the formula 2 Examples include groups in which some or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 10 carbon atoms, such as those represented by the following formula (I), have been substituted with a monovalent heteroatom-containing substituent. As the monovalent heteroatom-containing substituent, the monovalent heteroatom-containing substituents for X described above can be suitably used. Among these, preferred are cyanoalkyl groups having 1 to 5 carbon atoms, such as a cyanomethyl group, a cyanoethyl group, and a cyanopropyl group, and fluorinated alkyl groups having 1 to 5 carbon atoms, such as a trifluoromethyl group and a 2,2,2-trifluoroethyl group.

[0049] In the above formulas (1-1) and (1-4), R 3 and R 4 A ring structure having 3 to 20 ring members formed by bonding together with the carbon atoms to which they are bonded, and R 8 and R 9Examples of the ring structure having 3 to 20 ring members formed by bonding together with the carbon atoms to which they are bonded include an alicyclic structure, an aromatic ring structure, and a heterocyclic structure containing a divalent heteroatom-containing linking group for X between carbon atoms of these ring structures. Some or all of the hydrogen atoms contained in the ring structure may be substituted with substituents. In this specification, the term "number of ring members" refers to the number of atoms constituting the ring structure, and in the case of a polycyclic ring, refers to the number of atoms constituting the polycyclic ring.

[0050] Examples of the alicyclic structure include structures corresponding to 3 to 20 carbon atoms among the structures possessed by the monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms in the above X. Examples of the aromatic ring structure include structures corresponding to 3 to 20 carbon atoms among the structures possessed by the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms in the above X. Examples of the heterocyclic structure include a lactone structure, a cyclic carbonate structure, a cyclic acetal, a cyclic ether, a sultone structure, or a structure containing a combination thereof.

[0051] The heterocyclic structure is preferably a lactone structure. Examples of the lactone structure include monocyclic lactone structures such as a propiolactone structure, a butyrolactone structure, a valerolactone structure, and a caprolactone structure, and polycyclic lactone structures such as a cyclopentanelactone structure, a cyclohexanelactone structure, a norbornanelactone structure, a benzobutyrolactone structure, and a benzovalerolactone structure. Among these, a butyrolactone structure and a norbornanelactone structure are preferred.

[0052] Examples of the substituent that substitutes some or all of the hydrogen atoms in the ring structure include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a hydroxy group; a carboxy group; a cyano group; a nitro group; an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, an acyloxy group, or a group in which the hydrogen atoms of these groups are substituted with halogen atoms; and an oxo group (═O).

[0053] R 3 and R 4 and R 8 and R9 When R 2 and R 7 is preferably a hydrogen atom.

[0054] In the above formulas (1-2) and (1-3), R 5 and R 6 Examples of the monovalent organic group having 1 to 10 carbon atoms represented by the formula (I) include the same groups having 1 to 10 carbon atoms as those exemplified as the monovalent organic group having 1 to 30 carbon atoms for X above.

[0055] R in the above formula (1-1) 4 , R in the above formula (1-2) 5 , R in the above formula (1-3) 6 and R in the above formula (1-4) 9 are preferably each independently a monovalent heteroatom-containing group having 1 to 10 carbon atoms. By including such a polar structure, it is possible to improve the rectangularity of the pattern during alkaline development. As the monovalent heteroatom-containing group having 1 to 10 carbon atoms, R 4 Examples of such heteroatom-containing monovalent groups include those having 1 to 10 carbon atoms and represented by the following formulae:

[0056] When X in the above formula (1) is represented by the above formula (1-1), examples of the first structural unit include structural units derived from compounds represented by the following formulas (1-1-1) to (1-1-9) (hereinafter also referred to as "first structural units (1-1-1) to (1-1-9)").

[0057] [ka]

[0058] When X in the above formula (1) is represented by the above formula (1-2), examples of the first structural unit include structural units derived from compounds represented by the following formulas (1-2-1) to (1-2-6) (hereinafter also referred to as "first structural units (1-2-1) to (1-2-6)").

[0059] [ka]

[0060] When X in the above formula (1) is represented by the above formula (1-3), examples of the first structural unit include structural units derived from compounds represented by the following formulas (1-3-1) to (1-3-6) (hereinafter also referred to as "first structural units (1-3-1) to (1-3-6)").

[0061] [ka]

[0062] When X in the above formula (1) is represented by the above formula (1-4), examples of the first structural unit include structural units derived from compounds represented by the following formulas (1-4-1) to (1-4-6) (hereinafter also referred to as "first structural units (1-4-1) to (1-4-6)").

[0063] [ka]

[0064] X in the above formula (1) is preferably represented by the above formula (1-3) or (1-4). These structures have high hydrophilicity due to the generation of an alcoholic hydroxy group upon dissociation of the alkali-dissociable group, and therefore can exert a high level of suppression of residue generation.

[0065] The lower limit of the content of the first structural unit in all structural units constituting the polysiloxane is preferably 5 mol%, more preferably 8 mol%, and even more preferably 10 mol%. The upper limit of the content of the first structural unit is preferably 40 mol%, more preferably 35 mol%, and even more preferably 30 mol%. By having the content of the first structural unit within the above range, it is possible to efficiently form a silicon-containing film that can form a resist pattern with good pattern rectangularity.

[0066] (second structural unit) The polysiloxane preferably has a second structural unit represented by the following formula (2) as a structural unit other than the first structural unit: When the polysiloxane has the second structural unit, the oxygen gas etching resistance of the silicon-containing film formed from the silicon-containing composition can be improved.

[0067] [ka] (In the above formula (2), R 12 is a substituted or unsubstituted monovalent alkoxy group having 1 to 20 carbon atoms, a hydroxy group, or a halogen atom. e is an integer of 0 to 3. When e is 2 or more, multiple R 12 are the same or different.)

[0068] In the above formula (2), R 12 Specific examples of the monovalent alkoxy group having 1 to 20 carbon atoms represented by the formula (I) include alkoxy groups such as a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, etc. Furthermore, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0069] In the above formula (2), R 12 is preferably an alkoxy group, more preferably a methoxy group.

[0070] When the first polysiloxane contains the second structural unit, the lower limit of the content of the second structural unit relative to all structural units constituting the first polysiloxane is preferably 40 mol%, more preferably 45 mol%, and even more preferably 50 mol%, and the upper limit of the content of the second structural unit is preferably 95 mol%, more preferably 90 mol%, and even more preferably 85 mol%.

[0071] (Third structural unit) The polysiloxane may have a third structural unit represented by the following formula (3) as a structural unit other than the first structural unit: By having the third structural unit, an anti-reflection effect is exhibited when the resist film is exposed to light, and a resist pattern with excellent cross-sectional rectangularity can be formed.

[0072] [ka]

[0073] In the above formula (3), R 11 is a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. d is an integer of 1 to 3. When d is 2 or more, multiple R 11 may be the same or different.)

[0074] Above R 11 Examples of the aryl group having 6 to 20 carbon atoms represented by the formula (I) include a phenyl group, a naphthyl group, and an anthracenyl group.

[0075] Examples of the substituent on the aryl group include an alkyl group having 1 to 5 carbon atoms, a hydroxy group, a halogen atom, etc. Among these, a halogen atom is preferred, and a fluorine atom is more preferred.

[0076] Examples of the third structural unit include structural units derived from compounds represented by the following formulas (3-1) to (3-8) (hereinafter also referred to as "third structural units (1) to (8)").

[0077] [ka]

[0078] When the polysiloxane has a third structural unit, the lower limit of the content of the third structural unit in the total structural units constituting the polysiloxane is preferably 1 mol%, more preferably 5 mol%, and even more preferably 8 mol%. The upper limit of the content of the third structural unit is preferably 30 mol%, more preferably 20 mol%, and even more preferably 15 mol%. By having the content of the third structural unit in the above range, a silicon-containing film with better anti-reflection performance can be formed.

[0079] (fourth structural unit) The polysiloxane preferably has a fourth structural unit represented by the following formula (4) as a structural unit other than the first structural unit. [ka]

[0080] In the above formula (4), R 13 is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms. c is an integer of 1 to 3. When c is 2 or more, multiple R 13 are the same or different.

[0081] Above R 13 Examples of the alkyl group having 1 to 10 carbon atoms represented by the formula include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a t-butyl group.

[0082] Examples of the substituent of the alkyl group include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom. 13 The alkyl group having 1 to 10 carbon atoms represented by the following formula is preferably unsubstituted.

[0083] c is preferably 1 or 2, and more preferably 1.

[0084] When the polysiloxane has a fourth structural unit, the lower limit of the content of the fourth structural unit in the total structural units constituting the polysiloxane is preferably 4 mol%, more preferably 6 mol%, and even more preferably 8 mol%. The upper limit of the content is preferably 30 mol%, more preferably 20 mol%, and even more preferably 15 mol%. By setting the content of the fourth structural unit in the polysiloxane within the above range, the silicon-containing film made from the silicon-containing composition can impart excellent cross-sectional rectangularity to the resist pattern.

[0085] The lower limit of the polysiloxane content (the total content when multiple polysiloxanes are included) in the silicon-containing composition is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass, based on the total components contained in the silicon-containing composition.The upper limit of the content is preferably 10% by mass, more preferably 7.5% by mass, and even more preferably 5% by mass.

[0086] The polysiloxane is preferably in the form of a polymer. In this specification, the term "polymer" refers to a compound having two or more structural units, and when two or more identical structural units are consecutive in a polymer, this structural unit is also referred to as a "repeating unit." When the polysiloxane is in the form of a polymer, the lower limit of the polystyrene-equivalent weight average molecular weight (Mw) of the polysiloxane measured by gel permeation chromatography (GPC) is preferably 1,000, more preferably 1,100, even more preferably 1,200, and particularly preferably 1,500. The upper limit of the Mw is preferably 8,000, more preferably 5,000, even more preferably 3,000, and particularly preferably 2,800. The method for measuring the Mw of the polysiloxane is as described in the Examples.

[0087] [Method for synthesizing polysiloxane] Polysiloxanes can be synthesized by conventional methods using monomers that provide each structural unit. For example, a monomer that provides the first structural unit and, if necessary, monomers that provide other structural units can be hydrolyzed and condensed in a solvent in the presence of a catalyst such as oxalic acid and water, and the solution containing the resulting hydrolysis and condensation product can then be purified, preferably by solvent substitution in the presence of a dehydrating agent such as trimethyl orthoformate. It is believed that each monomer is incorporated into the polysiloxane regardless of its type through the hydrolysis and condensation reaction. Therefore, the content ratio of the first structural unit and other structural units in the synthesized polysiloxane is usually equivalent to the ratio of the amounts of each monomer used in the synthesis reaction.

[0088] [solvent] The solvent is not particularly limited, and examples thereof include alcohol solvents, ketone solvents, ether solvents, ester solvents, nitrogen-containing solvents, water, etc. The silicon-containing composition may contain one or more solvents.

[0089] Examples of alcohol solvents include monoalcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, and iso-butanol, and polyhydric alcohol solvents such as ethylene glycol, 1,2-propylene glycol, diethylene glycol, and dipropylene glycol.

[0090] Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-butyl ketone, and cyclohexanone.

[0091] Examples of ether solvents include ethyl ether, isopropyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and tetrahydrofuran.

[0092] Examples of ester solvents include ethyl acetate, γ-butyrolactone, n-butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, ethyl propionate, n-butyl propionate, methyl lactate, and ethyl lactate.

[0093] Examples of nitrogen-containing solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0094] Among these, ether-based solvents or ester-based solvents are preferred, and ether-based solvents or ester-based solvents having a glycol structure are more preferred because of their excellent film-forming properties.

[0095] Examples of ether-based solvents and ester-based solvents having a glycol structure include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc. Among these, propylene glycol monomethyl ether acetate or propylene glycol monoethyl ether is preferred, and propylene glycol monomethyl ether is more preferred.

[0096] The lower limit of the solvent content in the silicon-containing composition is preferably 90 mass%, more preferably 92.5 mass%, and even more preferably 95 mass%, based on all components contained in the silicon-containing composition. The upper limit of the solvent content is preferably 99.9 mass%, more preferably 99.5 mass%, and even more preferably 99 mass%.

[0097] (optional ingredient) Examples of optional components include photoacid generators, basic compounds (including base generators), acid diffusion controllers, radical generators, surfactants, colloidal silica, colloidal alumina, organic polymers, etc. The silicon-containing composition can contain one or more optional components.

[0098] When the silicon-containing composition contains an optional component, the content of the optional component in the silicon-containing composition can be determined appropriately depending on the type of optional component used and within a range that does not impair the effects of the present invention.

[0099] <Method for preparing silicon-containing composition> The method for preparing the silicon-containing composition is not particularly limited, and the composition can be prepared according to a conventional method, for example, by mixing a polysiloxane solution, a solvent, and, if necessary, optional components in a predetermined ratio, and then filtering the resulting mixed solution preferably through a filter having a pore size of 0.2 μm or less.

[0100] <Method of manufacturing semiconductor substrate> The method for producing a semiconductor substrate according to this embodiment includes the steps of: applying a silicon-containing composition directly or indirectly to a substrate to form a silicon-containing film (hereinafter also referred to as a "silicon-containing film-forming step"); applying a resist film-forming composition directly or indirectly to the silicon-containing film to form a resist film (hereinafter also referred to as a "resist film-forming step"); exposing the resist film to radiation (hereinafter also referred to as an "exposure step"); and developing the exposed resist film to form a resist pattern (hereinafter also referred to as a "development step"). In the silicon-containing film-forming step, the silicon-containing composition described above is used as the silicon-containing composition.

[0101] The method for manufacturing a semiconductor substrate may further include, as necessary, a step of forming an organic underlayer film directly or indirectly on the substrate (hereinafter also referred to as an "organic underlayer film forming step") prior to the silicon-containing film forming step.

[0102] Furthermore, after the developing step, the method may further include a step of etching the silicon-containing film using the resist pattern as a mask to form a silicon-containing film pattern (hereinafter also referred to as a "silicon-containing film pattern forming step"); a step of etching using the silicon-containing film pattern as a mask (hereinafter referred to as an "etching step"); and a step of removing the silicon-containing film pattern with a basic liquid (hereinafter referred to as a "removing step").

[0103] According to the method for producing a semiconductor substrate, by using the silicon-containing composition described above as the silicon-containing composition in the silicon-containing composition application step, a resist pattern with excellent rectangular cross-sectional shape can be formed on the silicon-containing film.

[0104] Hereinafter, each step included in the semiconductor substrate manufacturing method will be described, including an organic underlayer film forming step prior to the silicon-containing film forming step, and a silicon-containing film pattern forming step, etching step, and removal step after the development step.

[0105] [Organic lower layer film formation process] In this step, an organic underlayer film is formed directly or indirectly on the substrate prior to the silicon-containing film-forming step. This step is an optional step. By this step, an organic underlayer film is formed directly or indirectly on the substrate.

[0106] The organic underlayer film can be formed by coating an organic underlayer film-forming composition, etc. Examples of methods for forming an organic underlayer film by coating an organic underlayer film-forming composition include a method in which the organic underlayer film-forming composition is directly or indirectly applied to a substrate, and the resulting coating film is heated or exposed to light to cure it. Examples of the organic underlayer film-forming composition that can be used include "HM8006" manufactured by JSR Corporation. The heating and exposure conditions can be determined appropriately depending on the type of organic underlayer film-forming composition used, etc.

[0107] An example of a case where an organic underlayer film is formed indirectly on a substrate is a case where an organic underlayer film is formed on a low dielectric insulating film formed on a substrate.

[0108] [Silicon-containing film formation process] In this process, a silicon-containing film is formed by directly or indirectly applying a silicon-containing composition to a substrate. This process forms a coating film of the silicon-containing composition directly or indirectly on the substrate, and the coating film is usually cured by heating to form the silicon-containing film.

[0109] In this step, the silicon-containing composition used is the silicon-containing composition described above.

[0110] Examples of the substrate include insulating films such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, and resin substrates. The substrate may also be a substrate patterned with wiring grooves (trenches), plug grooves (vias), and the like.

[0111] The method for applying the silicon-containing film-forming composition is not particularly limited, and examples thereof include rotary coating.

[0112] Examples of indirectly applying the silicon-containing film-forming composition to a substrate include applying the silicon-containing composition to another film formed on the substrate, such as an organic underlayer film formed by the organic underlayer film-forming step, an anti-reflection film, or a low-dielectric insulating film.

[0113] When heating the coating film, the atmosphere is not particularly limited, and examples include air and nitrogen atmospheres. Typically, the coating film is heated in air. When heating the coating film, the heating temperature, heating time, and other conditions can be determined appropriately. The lower limit of the heating temperature is preferably 90°C, more preferably 150°C, and even more preferably 200°C. The upper limit of the heating temperature is preferably 550°C, more preferably 450°C, and even more preferably 300°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.

[0114] When the silicon-containing film-forming composition contains an acid generator, and this acid generator is a radiation-sensitive acid generator, the formation of the silicon-containing film can be promoted by combining heating and exposure. Examples of the radiation used for exposure include the same radiation as exemplified in the exposure step described below.

[0115] The lower limit of the average thickness of the silicon-containing film formed by this process 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 300 nm, and even more preferably 200 nm. The method for measuring the average thickness of the silicon-containing film is described in the Examples.

[0116] [Resist film formation process] In this step, a resist film is formed by applying a resist film-forming composition directly or indirectly to the silicon-containing film. By this step, a resist film is formed directly or indirectly on the silicon-containing film.

[0117] The method for applying the resist film-forming composition is not particularly limited, and examples thereof include a rotary coating method.

[0118] To explain this process in more detail, for example, a resist composition is applied so that the resist film to be formed has a predetermined thickness, and then the resist film is formed by volatilizing the solvent in the applied film through pre-baking (hereinafter also referred to as "PB").

[0119] The PB temperature and PB time can be appropriately determined depending on the type of 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.

[0120] As the resist film-forming composition used in this step, it is preferable to use a so-called positive resist film-forming composition for alkaline development. In the silicon-containing film formed above, the alkali-dissociable groups of the polysiloxane are dissociated by the alkaline solution for alkaline development, thereby increasing the solubility of the resist film near the interface between the resist film and the silicon-containing film, and forming a resist pattern with excellent pattern rectangularity. As such a resist film-forming composition, for example, a resin having an acid-dissociable group or a radiation-sensitive acid generator is contained, and a positive resist film-forming composition for exposure with ArF excimer laser light (for ArF exposure) or exposure with extreme ultraviolet light (for EUV exposure) is preferred.

[0121] [Exposure process] In this step, the resist film formed in the resist film-forming composition application step is exposed to radiation. This step generates a difference in solubility in an alkaline solution, which is a developer, between the exposed and unexposed areas of the resist film. More specifically, the solubility of the exposed areas of the resist film in an alkaline solution is increased.

[0122] The radiation used for exposure can be appropriately selected depending on the type of resist film-forming composition used. Examples include visible light, ultraviolet light, far ultraviolet light, electromagnetic waves such as X-rays and gamma rays, and particle beams such as electron beams, molecular beams, and ion beams. Among these, far ultraviolet light is preferred, with 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), and extreme ultraviolet light (wavelength 13.5 nm, also known as "EUV") being more preferred, and ArF excimer laser light or EUV being even more preferred. Furthermore, exposure conditions can be appropriately determined depending on the type of resist film-forming composition used.

[0123] Furthermore, in this step, 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.

[0124] [Development process] In this step, the exposed resist film is developed. The development of the exposed resist film is preferably alkaline development. The exposure step causes a difference in solubility in an alkaline solution, which is a developer, between the exposed and unexposed portions of the resist film, and thus alkaline development removes the exposed portions, which have a relatively high solubility in an alkaline solution, thereby forming a resist pattern.

[0125] The developer used in alkaline development is not particularly limited, and known developers can be used. Examples of developers for alkaline development include alkaline aqueous solutions containing at least one alkaline compound 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, a TMAH aqueous solution is preferred, and a 2.38 mass % TMAH aqueous solution is more preferred.

[0126] When organic solvent development is performed, examples of the developer include the same solvents as those exemplified as the solvents for the silicon-containing composition described above.

[0127] In this step, washing and / or drying may be carried out after the development.

[0128] [Silicon-containing film pattern formation process] In this step, the silicon-containing film is etched using the resist pattern as a mask to form a silicon-containing film pattern.

[0129] The etching may be either dry etching or wet etching, but dry etching is preferred.

[0130] 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 elemental composition of the silicon-containing film to be etched. Examples include fluorine-based gases such as CHF3, CF4, C2F6, C3F8, and SF6; chlorine-based gases such as Cl2 and BCl3; oxygen-based gases such as O2, O3, and H2O; reducing gases such as H2, NH3, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, HF, HI, HBr, HCl, NO, and NH3; and inert gases such as He, N2, and Ar. These gases can also be used in combination. For dry etching of silicon-containing films, fluorine-based gases are typically used, and mixtures of these with oxygen-based gases and inert gases are preferably used.

[0131] [Etching process] In this step, etching is performed using the silicon-containing film pattern as a mask. More specifically, etching is performed one or more times using the pattern formed on the silicon-containing film obtained in the silicon-containing film pattern forming step as a mask to obtain a patterned substrate.

[0132] When an organic underlayer film is formed on a substrate, a pattern of the organic underlayer film is formed by etching the organic underlayer film using the silicon-containing film pattern as a mask, and then a pattern is formed on the substrate by etching the substrate using this organic underlayer film pattern as a mask.

[0133] The etching may be either dry etching or wet etching, but dry etching is preferred.

[0134] Dry etching for forming a pattern on the organic underlayer film can be performed using a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the elemental composition of the silicon-containing film and the organic underlayer film to be etched. The etching gas can be suitably selected from the gases used for etching the silicon-containing film described above, and these gases can also be used in combination. An oxygen-based gas is usually used for dry etching the organic underlayer film using the silicon-containing film pattern as a mask.

[0135] Dry etching when forming a pattern on a substrate using an organic underlayer film pattern as a mask can be carried out using a known dry etching apparatus. The etching gas used in dry etching can be appropriately selected depending on the elemental composition of the organic underlayer film and the substrate to be etched, and examples thereof include the same etching gases as those exemplified as the etching gases used in dry etching of the organic underlayer film. Etching may be carried out multiple times using different etching gases. Note that, if a silicon-containing film remains on the substrate, the resist underlayer pattern, or the like after the substrate pattern formation step, the silicon-containing film can be removed by carrying out the removal step described below.

[0136] [Removal process] In this step, the silicon-containing film pattern is removed with a basic solution. This step removes the silicon-containing film from the substrate. Furthermore, it is possible to remove silicon-containing film residues after etching.

[0137] The basic solution is not particularly limited as long as it is a basic solution containing a basic compound. Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide (hereinafter also referred to as "TMAH"), tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4.0]-7-undecene, and 1,5-diazabicyclo[4.3.0]-5-nonene. Among these, ammonia is preferred from the viewpoint of avoiding damage to the substrate.

[0138] From the viewpoint of further improving the removability of the silicon-containing film, the basic liquid is preferably a liquid containing a basic compound and water, or a liquid containing a basic compound, hydrogen peroxide, and water.

[0139] The method for removing the silicon-containing film is not particularly limited as long as it is a method that can bring the silicon-containing film into contact with a basic liquid, and examples thereof include a method of immersing the substrate in a basic liquid, a method of spraying a basic liquid, and a method of applying a basic liquid.

[0140] The conditions for removing the silicon-containing film, such as temperature and time, are not particularly limited and can be appropriately determined depending on the thickness of the silicon-containing film, the type of basic solution used, and the like. The lower limit of the temperature is preferably 20°C, more preferably 40°C, and even more preferably 50°C. The upper limit of the temperature is preferably 300°C, more preferably 100°C. The lower limit of the time is preferably 5 seconds, more preferably 30 seconds. The upper limit of the time is preferably 10 minutes, more preferably 180 seconds.

[0141] In this step, after removing the silicon-containing film, washing and / or drying may be carried out. [Example]

[0142] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0143] [Measurement of weight average molecular weight (Mw)] The weight average molecular weight (Mw) of the polysiloxane was measured by gel permeation chromatography (GPC) using Tosoh Corporation's GPC columns (two "G2000HXL", one "G3000HXL", and one "G4000HXL") under the following conditions: (Measurement conditions) Eluent: tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: differential refractometer Standard material: monodisperse polystyrene

[0144] [Polysiloxane concentration in solution] 0.5 g of the polysiloxane solution was baked at 250°C for 30 minutes, and the mass of the residue obtained was measured. The concentration of the polysiloxane solution (unit: mass%) was calculated by dividing the mass of the residue by the mass of the polysiloxane solution.

[0145] [Average thickness of silicon-containing film] The average thickness of the silicon-containing film was measured using a spectroscopic ellipsometer (JAWOOLLAM's "M2000D"). Specifically, the film thickness was measured at nine arbitrary positions at 5 cm intervals, including the center of the silicon-containing film, and the average value of these film thicknesses was calculated to obtain the average thickness.

[0146] <Synthesis of Polysiloxane> The monomers (hereinafter also referred to as "monomers (M-1) to (M-17)") used in the synthesis in Synthesis Examples 1 to 20 are shown below. In the following Synthesis Examples 1-1 to 1-20, mol % refers to the value for each monomer when the total number of moles of the monomers (M-1) to (M-17) used is taken as 100 mol %.

[0147] [ka]

[0148] [Synthesis Example 1] Synthesis of polysiloxane (A-1) In a reaction vessel, the above compounds (M-1), (M-3), and (M-4) were dissolved in 62 parts by mass of propylene glycol monoethyl ether to a molar ratio of 80 / 10 / 10 (mol %) to prepare a monomer solution. The temperature inside the reaction vessel was raised to 60°C, and 40 parts by mass of a 9.1% by mass aqueous oxalic acid solution was added dropwise over 20 minutes while stirring. The reaction started when the dropwise addition began, and was carried out for 4 hours. After completion of the reaction, the reaction vessel was cooled to below 30°C. 550 parts by mass of propylene glycol monoethyl ether was added to the cooled reaction solution, and water, alcohols produced by the reaction, and excess propylene glycol monoethyl ether were removed using an evaporator to obtain a propylene glycol monoethyl ether solution of polysiloxane (A-1). The Mw of polysiloxane (A-1) was 1,600. The concentration of polysiloxane (A-1) in the propylene glycol monoethyl ether solution was 7.2% by mass.

[0149] [Synthesis Examples 2 to 20] Synthesis of polysiloxanes (A-2) to (A-17) and (a-1) to (a-3) Propylene glycol monoethyl ether solutions of polysiloxanes (A-2) to (A-17) and (a-1) to (a-3) were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of each monomer shown in Table 1 below were used. A "-" next to a monomer in Table 1 below indicates that the corresponding monomer was not used. The Mw of the obtained polysiloxanes and their concentrations (mass%) in the solution are also shown in Table 1 below.

[0150] [Table 1]

[0151] <Preparation of Silicon-Containing Composition> The solvents and photoacid generators used in preparing the silicon-containing compositions are shown below. In Examples 1 to 19 and Comparative Examples 1 to 3, unless otherwise specified, parts by mass are values ​​based on 10,000 parts by mass of the total mass of the components used.

[0152] [solvent] B-1: Propylene glycol monoethyl ether [C] Photoacid generator C-1: A compound represented by the following formula (C-1):

[0153] [ka]

[0154] [Example 1] Preparation of silicon-containing composition (J-1) 100 parts by mass of (A-1) as polysiloxane and 9,900 parts by mass of (B-1) as solvent (including the solvent contained in the polysiloxane solution) were mixed, and the resulting solution was filtered through a polytetrafluoroethylene filter with a pore size of 0.2 μm to prepare a silicon-containing composition (J-1).

[0155] [Examples 2 to 19 and Comparative Examples 1 to 3] Preparation of silicon-containing compositions (J-2) to (J-19) and (j-1) to (j-3) Silicon-containing compositions (J-2) to (J-19) of Examples 2 to 19 and silicon-containing compositions (j-1) to (j-3) of Comparative Examples 1 to 3 were prepared in the same manner as in Example 1, except that the types and amounts of each component shown in Table 2 below were used.

[0156] <Evaluation> The pattern rectangularity was evaluated using the composition prepared above by the following method, and the evaluation results are shown in Table 2 below.

[0157] [Pattern rectangularity (ArF immersion exposure)] On a 12-inch silicon wafer, a material for forming an organic underlayer film (HM8006 of JSR Corporation) was applied by spin coating using a spin coater (CLEAN TRACK ACT12 of Tokyo Electron Limited), and then heated at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. The prepared silicon-containing composition was applied onto this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a silicon-containing film with an average thickness of 20 nm. A radiation-sensitive resin composition (ARF AR2772JN of JSR Corporation) was applied onto the formed silicon-containing film, 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 100 nm. Subsequently, using an ArF immersion exposure apparatus (S610C of Nikon Corporation), after exposure through a mask with a mask size for forming a 40 nm line / 80 nm pitch under the optical conditions of NA: 1.30 and Dipole, the substrate was heated at 100°C for 60 seconds and then cooled at 23°C for 60 seconds. Thereafter, using a 2.38 mass% TMAH aqueous solution (20°C to 25°C), development was carried out by the paddle method, followed by washing with water and drying to obtain an evaluation substrate on which a resist pattern was formed. A scanning electron microscope (CG-4000 of Hitachi High-Technologies Corporation) was used for measuring the length and observing the cross-sectional shape of the resist pattern of the above evaluation substrate. For the pattern rectangularity of a 1:1 line-and-space pattern with a line width of 40 nm on the above evaluation substrate, when the cross-sectional shape of the pattern was rectangular, it was evaluated as "A" (good), when the cross-sectional shape of the pattern was splayed (the shape of a pattern with a skirt pulled towards the space portion of the resist pattern), it was evaluated as "B" (slightly good), and when there were residues (defects) in the pattern, it was evaluated as "C" (bad). <EUV resist composition preparation>

[0158] The resist composition (R-1) for EUV exposure was prepared by mixing 100 parts by mass of a polymer having a structural unit (1) derived from 4-hydroxystyrene, a structural unit (2) derived from styrene, and a structural unit (3) derived from 4-t-butoxystyrene (the proportions of the structural units were (1) / (2) / (3)=65 / 5 / 30 (mol %)), 1.0 part by mass of triphenylsulfonium trifluoromethanesulfonate as a radiation-sensitive acid generator, and 4,400 parts by mass of ethyl lactate and 1,900 parts by mass of propylene glycol monomethyl ether acetate as a solvent, and filtering the resulting solution through a filter with a pore size of 0.2 μm.

[0159] [Pattern rectangularity (EUV exposure)] An organic underlayer film forming material (JSR Corporation's "HM8006") was applied to a 12-inch silicon wafer by a spin coating method using a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT12"), followed by heating at 250°C for 60 seconds to form an organic underlayer film with an average thickness of 100 nm. The silicon-containing composition prepared above was applied to this organic underlayer film, heated at 220°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a silicon-containing film with an average thickness of 20 nm. The resist composition (R-1) for EUV exposure was applied to the silicon-containing film formed above, heated at 130°C for 60 seconds, and then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. Next, an EUV scanner (ASML's "TWINSCAN" was used to apply the silicon-containing film. The resist film was irradiated with extreme ultraviolet light using an NXE:3300B (NA 0.3, sigma 0.9, quadrupole illumination, 1:1 line-and-space mask with a line width of 25 nm on the wafer). After irradiation with extreme ultraviolet light, the substrate was heated at 110°C for 60 seconds and then cooled at 23°C for 60 seconds. The resist was then developed by the puddle method using a 2.38% by mass TMAH aqueous solution (20°C to 25°C), washed with water, and dried to obtain an evaluation substrate with a resist pattern. The scanning electron microscope described above was used to measure and observe the resist pattern on the evaluation substrate. The pattern rectangularity of the 1:1 line-and-space pattern with a line width of 25 nm on the evaluation substrate was evaluated as "A" (good) if the cross-sectional shape of the pattern was rectangular, "B" (fairly good) if the cross-sectional shape of the pattern was footing (a pattern shape that footed toward the space portion of the resist pattern), and "C" (poor) if there were residues (defects) on the pattern.

[0160] [Table 2]

[0161] As is clear from the results in Table 2 above, the silicon-containing films formed from the silicon-containing compositions of the Examples were able to form resist patterns with excellent cross-sectional rectangularity on the films, compared to the silicon-containing films formed from the silicon-containing compositions of the Comparative Examples. [Industrial Applicability]

[0162] The silicon-containing composition and the method for producing a semiconductor substrate of the present invention can form a silicon-containing film that can form a resist pattern with excellent cross-sectional rectangularity. Therefore, they can be suitably used for producing semiconductor substrates, etc.

Claims

1. A polysiloxane having a first structural unit represented by the following formula (1): Solvent and Contains the content of the first structural unit in all structural units constituting the polysiloxane is 0.5 mol % or more and 40 mol % or less, A silicon-containing composition for forming a resist underlayer film. 【Chemistry 1】 (In the above formula (1), X is an alkali-dissociable group represented by the following formula (1-1) (excluding the cases represented by the following formula (1-2) and formula (1-3)), the following formula (1-2) (excluding the case represented by formula (1-3)), or the following formula (1-3). a is an integer of 1 to 3. When a is 2 or more, multiple Xs may be the same or different. R １ is a monovalent organic group having 1 to 20 carbon atoms, a hydroxy group, or a halogen atom. b is an integer of 0 to 2. When b is 2, two R １ are the same or different, provided that a+b is 3 or less. 【Chemistry 2】 (In the above formula (1-1), L １ is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R ２ is a hydrogen atom. ３ is a hydrogen atom, and R ４ is a monovalent heteroatom-containing group having 1 to 5 carbon atoms. 【Transformation 3】 (In the above formula (1-2), L ２ is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R ５ is a monovalent organic group having 1 to 10 carbon atoms. 【Chemistry 4】 (In the above formula (1-3), L ３ is a single bond or a divalent linking group. * is a bond to the silicon atom in the above formula (1). R ６ is a monovalent organic group having 1 to 10 carbon atoms.

2. R in the above formula (1-1) ４ is a monovalent heteroatom-containing group having 1 to 5 carbon atoms, and R ５ and R6 in the formula (1-3) are each independently a monovalent heteroatom-containing group having 1 to 10 carbon atoms.

3. The silicon-containing composition according to claim 1 or 2, wherein the polysiloxane compound has a second structural unit represented by the following formula (2): 【Transformation 5】 (In the above formula (2), R １２ is a substituted or unsubstituted monovalent alkoxy group having 1 to 20 carbon atoms, a hydroxy group, or a halogen atom. e is an integer of 0 to 3. When e is 2 or more, multiple R １２ are the same or different.)

4. 4. The silicon-containing composition according to claim 3, wherein the content of the second structural unit in all structural units constituting the polysiloxane is 40 mol % or more and 95 mol % or less.

5. The silicon-containing composition according to any one of claims 1 to 4, wherein the first polysiloxane has a third structural unit represented by the following formula (3): 【Transformation 6】 (In the above formula (3), R １１ is a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. d is an integer of 1 to 3. When d is 2 or more, multiple R １１ are the same or different.)

6. 6. The silicon-containing composition according to claim 5, wherein the content of the third structural unit in all structural units constituting the polysiloxane is 1 mol % or more and 30 mol % or less.

7. A step of directly or indirectly applying the silicon-containing composition according to any one of claims 1 to 6 to a substrate to form a silicon-containing film; a step of applying a resist film-forming composition directly or indirectly to the silicon-containing film to form a resist film; exposing the resist film to radiation; developing the exposed resist film to form a resist pattern; A method for manufacturing a semiconductor substrate, comprising:

8. The method for producing a semiconductor substrate according to claim 7 , further comprising the step of forming an organic underlayer film directly or indirectly on the substrate prior to the silicon-containing film forming step.

9. 9. The method for manufacturing a semiconductor substrate according to claim 7, wherein the exposed resist film is developed by alkaline development.

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