Resist underlayer film-forming composition

Abstract

[Problem] The present invention provides: a resist underlayer film composition that, through an increase in polymer heat-reflowability, exhibits an improved fillability into patterns during baking; a resist underlayer film that is the baked material of a coating film comprising this resist underlayer film composition; and a method for producing semiconductor devices comprising a step of forming this resist underlayer film. [Solution] The resist underlayer film-forming composition according to the present invention comprises a compound given by formula (A) or formula (B) and a solvent.

Description

Resist underlayer film-forming composition

[0001] The present invention relates to a resist underlayer film-forming composition for forming a planarizing film on a substrate having steps, and a method for producing a planarized laminated substrate using the resist underlayer film.

[0002] In the manufacture of semiconductor devices, microfabrication by lithography using a photoresist composition has traditionally been performed. This microfabrication process involves forming a thin film of the photoresist composition on a substrate to be processed, such as a silicon wafer, irradiating it with actinic rays such as ultraviolet light through a mask pattern bearing a semiconductor device pattern, developing the thin film, and then etching the substrate, such as a silicon wafer, using the resulting photoresist pattern as a protective film. However, in recent years, as the integration density of semiconductor devices has increased, the wavelength of the actinic rays used has been shortened from KrF excimer lasers (248 nm) to ArF excimer lasers (193 nm). As a result, the effects of diffuse reflection and standing waves from the substrate due to actinic rays have become a major problem, and methods of providing an anti-reflective coating between the photoresist and the substrate to be processed have become widely used. Furthermore, with the aim of achieving even finer processing, lithography techniques using extreme ultraviolet (EUV, 13.5 nm) or electron beam (EB) as actinic rays have also been developed. In EUV lithography and EB lithography, diffuse reflection and standing waves from the substrate are generally not generated, and therefore no specific anti-reflection coating is required. However, resist underlayer films have begun to be widely studied as auxiliary films for the purpose of improving the resolution and adhesion of resist patterns.

[0003] However, as the depth of focus decreases with the shortening of the exposure wavelength, it has become important to improve the planarization of the coating formed on the substrate in order to form a desired resist pattern with high precision. In other words, in order to manufacture semiconductor devices with fine design rules, a resist underlayer film that can be coated flatly on the substrate without any steps is essential.

[0004] For example, a resist underlayer film-forming composition containing a crosslinkable compound having an alkoxymethyl group having 2 to 10 carbon atoms and an alkyl group having 1 to 10 carbon atoms has been disclosed (see Patent Document 1). It has been shown that the use of this composition results in good embedding properties when applied to a substrate having a hole pattern.

[0005] Also disclosed is a resist underlayer film-forming composition containing a novolak resin using phenylnaphthylamine (see Patent Document 2).

[0006] Also disclosed is a resist underlayer film-forming composition containing a polymer obtained by reacting a novolak resin using phenylnaphthylamine with t-butoxystyrene (see Patent Document 3).

[0007] International Publication No. WO2014 / 208542 International Publication No. WO2013 / 047516 International Publication No. WO2015 / 151803

[0008] To prevent mixing when laminating a photoresist composition or a different resist underlayer film, a resist underlayer film-forming composition may be prepared by introducing a self-crosslinking moiety into the polymer resin, which is the main component, or by adding a crosslinking agent, crosslinking catalyst, or the like, and then baking at a high temperature to thermally cure the coating. This allows for lamination without mixing of the photoresist composition or the different resist underlayer film. However, since such a thermosetting resist underlayer film-forming composition contains a polymer having a thermally crosslinkable functional group such as a hydroxyl group, a crosslinking agent, and an acid catalyst (acid generator), when the composition fills a pattern (e.g., a hole or trench structure) formed on a substrate, the crosslinking reaction caused by baking increases the viscosity, which deteriorates the pattern filling ability and tends to reduce the planarization ability after film formation. The present invention aims to improve the thermal reflowability of the thermosetting resist underlayer film-forming composition, thereby improving the pattern filling ability during baking and improving the planarization ability of the resist underlayer film. A resist underlayer film-forming composition for forming a resist underlayer film that also has heat resistance is also provided.

[0009] That is, in a first aspect, the present invention relates to a resist underlayer film-forming composition containing a compound represented by the following formula (A) and / or formula (B), and a solvent: (In formula (A), Ar 1 and Ar 2 are each independently Z 1 represents a group consisting of one or more aromatic rings having 6 to 30 carbon atoms which may be substituted with 1 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms; X represents a single bond or an oxygen atom; Ar 7 When X is a single bond, Ar 1 and Ar 2 When X is an oxygen atom, it represents a phenyl group or a naphthyl group; 3 ~Ar 6 is the Ar 1 and Ar 2 is the same as the definition of R 2 and R 3 are the above R 1 and Y is a single bond or Z 2 n1, n2, m1, and m2 each represent 0 or 1, and n1, n2, m1, and m2 cannot all be 0 at the same time; 1 is at least one selected from the group consisting of a halogen atom, a hydroxy group, a cyano group, a methylamino group, a methyl ether group, a cyclic alkyl group, a benzene group, a pyridine group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms, 2 is at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms and a fluoroalkyl group having 1 to 10 carbon atoms.) In a second aspect, the present invention provides a compound represented by the formula (A) or (B), wherein Ar 1 ~Ar 6 are each independently a group consisting of one or more aromatic rings including a benzene ring. 1represents a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms. 3 ~Ar 6 and are the same group. The present invention relates, as a fifth aspect, to the resist underlayer film-forming composition according to any one of the first to fourth aspects, wherein the divalent group in formula (B) is a group selected from the group consisting of branched or linear alkylene groups having 1 to 15 carbon atoms, phenylene groups, naphthalene groups, anthracenyl groups, sulfonyl groups, carbonyl groups, ether groups, and thioether groups, or a group consisting of a combination thereof. The present invention relates, as a sixth aspect, to the resist underlayer film-forming composition according to the fifth aspect, wherein the divalent group in formula (B) is any one of the groups represented by the following: As a seventh aspect, the present invention provides a compound represented by the formula (B), 2 and / or R 3is a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms. The present invention relates, in an eighth aspect, to the resist underlayer film-forming composition according to any one of the first to seventh aspects, further comprising a crosslinking agent. The present invention, in a ninth aspect, to the resist underlayer film-forming composition according to any one of the first to eighth aspects, further comprising an acid and / or an acid generator. The present invention, in a tenth aspect, to the resist underlayer film-forming composition according to any one of the first to ninth aspects, wherein the solvent has a boiling point of 160°C or higher. The present invention, in an eleventh aspect, relates to a resist underlayer film, which is a baked product of a coating film comprising the resist underlayer film-forming composition according to any one of the first to tenth aspects.

[0019] In a twelfth aspect, the present invention relates to a method for manufacturing a semiconductor device, including a step of forming a resist underlayer film on a semiconductor substrate from the resist underlayer film-forming composition according to any one of the first to tenth aspects, a step of forming a resist film thereon, a step of forming a resist pattern by irradiating with light or an electron beam and developing, a step of etching the resist underlayer film using the resist pattern, and a step of processing a semiconductor substrate using the patterned resist underlayer film.

[0010] The resist underlayer film-forming composition of the present invention not only has high etching resistance, a good dry etching rate ratio, and good optical constants, but also the resist underlayer film obtained has good coverage even on so-called uneven substrates, has a small film thickness difference after filling, forms a flat film, and achieves finer substrate processing. In particular, the resist underlayer film-forming composition of the present invention is effective for a lithography process in which at least two resist underlayer films are formed for the purpose of reducing the resist film thickness, and the resist underlayer film is used as an etching mask.

[0011] Fig. 1 is a cross-sectional SEM photograph showing the results of a coating test on an uneven substrate carried out using the resist underlayer film-forming composition prepared in Comparative Example 1. The left image shows a dense pattern area, and the right image shows an open area. Fig. 2 is a cross-sectional SEM photograph showing the results of a coating test on an uneven substrate carried out using the resist underlayer film-forming composition prepared in Example 2. The left image shows a dense pattern area, and the right image shows an open area.

[0012] [Resist Underlayer Film Forming Composition] The resist underlayer film forming composition according to the present invention contains a compound represented by the following formula (A) and / or formula (B) and a solvent. (In formula (A), Ar 1 and Ar 2 are each independently Z 1 represents a group consisting of one or more aromatic rings having 6 to 30 carbon atoms which may be substituted with 1 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms; X represents a single bond or an oxygen atom; Ar 7 When X is a single bond, Ar 1 and Ar 2 When X is an oxygen atom, it represents a phenyl group or a naphthyl group; 3 ~Ar 6 is the Ar 1 and Ar 2 is the same as the definition of R 2 and R 3 are the above R 1 and Y is a single bond or Z 2 n1, n2, m1, and m2 each represent 0 or 1, and n1, n2, m1, and m2 cannot all be 0 at the same time; 1 is at least one selected from the group consisting of a halogen atom, a hydroxy group, a cyano group, a methylamino group, a methyl ether group, a cyclic alkyl group, a benzene group, a pyridine group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms, 2is at least one selected from the group consisting of alkyl groups having 1 to 10 carbon atoms and fluoroalkyl groups having 1 to 10 carbon atoms.

[0013] [Compound represented by formula (A)] In formula (A), Ar 1 and Ar 2 are each independently Z 1 represents a group consisting of one or more aromatic rings having 6 to 30 carbon atoms which may be substituted with

[0014] Substituent Z 1 is at least one selected from the group consisting of a halogen atom, a hydroxy group, a cyano group, a methylamino group, a methyl ether group, a cyclic alkyl group, a benzene group, a pyridine group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms.

[0015] Specific examples of the cyclic alkyl group include a cyclopropyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, a cyclopentyl group, a 1-methyl-cyclobutyl group, a 2-methyl-cyclobutyl group, a 3-methyl-cyclobutyl group, a 1,2-dimethyl-cyclopropyl group, a 2,3-dimethyl-cyclopropyl group, a 1-ethyl-cyclopropyl group, a 2-ethyl-cyclopropyl group, a cyclohexyl group, a 1-methyl-cyclopentyl group, a 2-methyl-cyclopentyl group, a 3-methyl-cyclopentyl group, a 1-ethyl-cyclobutyl group, a 2-ethyl-cyclobutyl group, a 3-ethyl-cyclobutyl group, a 1,2-dimethyl-cyclobutyl group, a 1,3-dimethyl-cyclobutyl group, a 2,2-dimethyl-cyclobutyl group, a 2,3-dimethyl-cyclobutyl group, a 2,4-dimethyl Examples of cycloalkyl groups include cycloalkyl groups such as 1-n-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl, and 2-ethyl-3-methyl-cyclopropyl groups; and bicycloalkyl groups such as bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, and bicyclodecyl groups, but are not limited to these.

[0016] The alkyl group having 1 to 10 carbon atoms, the alkenyl group having 2 to 10 carbon atoms, and the alkynyl group having 2 to 10 carbon atoms are described below. 1 See the explanation below.

[0017] Z 1 Examples of the group consisting of one or more aromatic rings having 6 to 30 carbon atoms which may be substituted with include Z 1The aromatic ring may be a single ring, or may be a group in which multiple benzene rings, naphthalene rings, or quinoline rings are bonded via carbon atoms, and among these, it is preferable to include a benzene ring. When multiple aromatic rings are present, the aromatic rings may be bonded to each other via a single bond. Examples of such combinations of aromatic rings include, but are not limited to, the following.

[0018]

[0019] In formula (A), R 1represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methylcyclopropyl group, a 2-methylcyclopropyl group, an n-pentyl group, a 1-methyln-butyl group, a 2-methyln-butyl group, a 3-methyln-butyl group, a 1,1-dimethyln-propyl group, a 1,2-dimethyln-propyl group, a 2,2-dimethyln-propyl group, a 1-ethyln-propyl group, Cyclopentyl group, 1-methylcyclobutyl group, 2-methylcyclobutyl group, 3-methylcyclobutyl group, 1,2-dimethylcyclopropyl group, 2,3-dimethylcyclopropyl group, 1-ethylcyclopropyl group, 2-ethylcyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2- Dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3 -ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,Examples include a 3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-1-methyl-cyclopropyl group, a 2-ethyl-2-methyl-cyclopropyl group, and a 2-ethyl-3-methyl-cyclopropyl group. These alkyl groups may be interrupted by an oxygen atom, a carbonyl group, or a carboxyl group. Among these, alkyl groups having 3 or less carbon atoms are preferred.

[0020] Examples of the alkenyl group having 2 to 10 carbon atoms include ethenyl, 1-propenyl, 2-propenyl, 1-methyl-1-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylethenyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethylethenyl, 1 ...ethyl-2-propylethenyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-1-propenyl, 1-methyl-2-propenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethenyl, 1-ethyl-2-propylethen methyl-2-propenyl group, 2-methyl-1-butenyl group, 2-methyl-2-butenyl group, 2-methyl-3-butenyl group, 3-methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propylethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl -1-pentenyl group, 1-methyl-2-pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butylethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group, 2-methyl-3-pentenyl group, 2-methyl-4-pentenyl group, 2-n-propyl-2-propenyl group, 3-methyl-1-pentenyl group, 3-methyl-2-pentenyl group, 3-methyl-3-pentenyl group, 3-methyl-4-pentenyl group, 3-ethyl-3-butenyl group, 4-methyl-1-pentenyl group, 4-methyl-2-pentenyl group , 4-methyl-3-pentenyl group, 4-methyl-4-pentenyl group, 1,1-dimethyl-2-butenyl group, 1,1-dimethyl-3-butenyl group, 1,2-dimethyl-1-butenyl group, 1,2-dimethyl-2-butenyl group, 1,2-dimethyl-3-butenyl group, 1-methyl-2-ethyl-2-propenyl group, 1-s-butylethenyl group, 1,3-dimethyl-1-butenyl group, 1,3-dimethyl-2-butenyl group, 1,3-dimethyl-3-butenyl group, 1-i-butylethenyl group, 2,2-dimethyl-3-butenyl group, 2,3-dimethyl-1-butenyl group, 2,3-dimethyl-2-butenyl group, 2,3-dimethyl-3-butenyl group, 2-i-propyl-2-propenyl group, 3,3-dimethyl-1-butenyl group, 1-ethyl-1-butenyl group, 1-ethyl-2-butenyl group, 1-ethyl-3-butenyl group, 1-n-propyl-1-propenyl group, 1-n-propyl-2-propenyl group, 2-ethyl-1-butenyl group, 2-ethyl-2-butenyl group, 2-ethyl-3-butenyl group, 1,1,2-trimethyl-2-propenyl group, 1-t-butylethenyl group, 1-methyl-1-ethyl-2-propenyl group, 1-ethyl-2-methyl-1-propenyl group, 1-ethyl-2-methyl-2-propenyl group, 1-i-propyl-1-propenyl group, 1-i- Examples include propyl-2-propenyl group, 1-methyl-2-cyclopentenyl group, 1-methyl-3-cyclopentenyl group, 2-methyl-1-cyclopentenyl group, 2-methyl-2-cyclopentenyl group, 2-methyl-3-cyclopentenyl group, 2-methyl-4-cyclopentenyl group, 2-methyl-5-cyclopentenyl group, 2-methylene-cyclopentyl group, 3-methyl-1-cyclopentenyl group, 3-methyl-2-cyclopentenyl group, 3-methyl-3-cyclopentenyl group, 3-methyl-4-cyclopentenyl group, 3-methyl-5-cyclopentenyl group, 3-methylene-cyclopentyl group, 1-cyclohexenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group. These alkenyl groups may be interrupted by an oxygen atom, a carbonyl group, or a carboxyl group. Among these, alkenyl groups having 5 or fewer carbon atoms are preferred.

[0021] Examples of the alkynyl group having 2 to 10 carbon atoms include an ethynyl group, a 1-propynyl group, a 1-butynyl group, a 1-pentynyl group, a 1-hexynyl group, a 1-methyl-3-pentynyl group, a 1-methyl-3-hexynyl group, and a 2-methyl-3-hexynyl group, and also include alkynyl groups exemplified below.

[0022] (Alkynyl groups having 2 to 10 carbon atoms are R 1 In the case of the above, * represents a bond to the nitrogen atom. 1In the case where * represents a bond to a combination of aromatic rings.

[0023] R in formula (A) 1 is preferably a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms.

[0024] In formula (A), X represents a single bond or an oxygen atom. 7 When X is a single bond, 1 and Ar 2 When X is an oxygen atom, it represents a phenyl group or a naphthyl group.

[0025] Examples of such compounds represented by formula (A) include the following compounds.

[0026] [Compound represented by formula (B)] In formula (B), Ar 3 ~Ar 6 is the aforementioned Ar 1 and Ar 2 and each independently represents Z 1 Ar represents a group consisting of one or more aromatic rings having 6 to 30 carbon atoms, which may be substituted with 3 ~Ar 6 are preferably the same group. 3 ~Ar 6 are each independently Z 1 In formula (B), R represents a group consisting of one or more aromatic rings having 6 to 30 carbon atoms, including a benzene ring, which may be substituted with 2 and R 3 are the aforementioned R 1 The definition is the same as that of R. 2 and / or R 3 is preferably a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms. 2 and R 3 may be different groups, but are preferably the same group.

[0027] In formula (B), Y is a single bond or Z 2The substituent Z represents a divalent group which may be substituted with the following. Such a divalent group is a group selected from the group consisting of a branched or linear alkylene group having 1 to 15 carbon atoms, a phenylene group, a naphthalene group, an anthracenyl group, a sulfonyl group, a carbonyl group, an oxygen atom (an ether group), and a sulfur atom (a thioether group), or a group consisting of a combination thereof. 2 When substituted with, the substituent Z 2 The substituent Z 2 is at least one selected from the group consisting of alkyl groups having 1 to 10 carbon atoms and fluoroalkyl groups having 1 to 10 carbon atoms. Examples of the fluoroalkyl groups having 1 to 10 carbon atoms include perfluoromethyl groups, perfluoroethyl groups, perfluoropropyl groups, and perfluorobutyl groups. 2 In formula (B), n1, n2, m1, and m2 represent 0 or 1, and it is preferred that n1, n2, m1, and m2 are not all 0 at the same time, and that at least one of n1 and n2 is 1 and at least one of m1 and m2 is 1.

[0028] The divalent groups described above may be one type alone or two or more types in combination. Examples of the combination include, but are not limited to, the groups exemplified below.

[0029]

[0030] Examples of such compounds represented by formula (B) include the following compounds.

[0031] [Synthesis of Compound Represented by Formula (A) or Formula (B)] The compound represented by formula (A) or formula (B) can be synthesized, for example, by reacting an amine compound or diamine compound represented by the following formulas (C) to (E) with a compound represented by formula (G) to form a substituent R 1 After introducing the compound represented by formula (F), a substituent Ar 1 A method of introducing the substituent R1 and a substituent Ar 1 The order of introduction may be reversed from that described above and can be selected appropriately.

[0032] X, Y, Ar 1 , R 1 is as described above. 8 is Ar in the above formula (A). 7 It is the same as Z. 1 , Z 2 is a removable group such as a hydroxyl group, a halogen group, or a sulfo group, and Z 1 is preferably a hydroxyl group, and Z 2 is preferably a halogen group.

[0033] The reaction products suitable for use in the present invention will be described in the examples.

[0034] [Solvent] The solvent for the resist underlayer film-forming composition of the present invention is not particularly limited, as long as it can dissolve the reaction product. In particular, since the resist underlayer film-forming composition of the present invention is used in the state of a homogeneous solution, it is recommended to use a solvent that is generally used in lithography processes in combination with the composition, taking into consideration its coating performance.

[0035] Examples of such solvents include methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl isobutyl carbinol, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate,Isopropyl butyrate, butyl butyrate, isobutyl butyrate, ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropyl acetate, 3-methyl-3-methoxybutyl acetate, Examples of suitable solvents include 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

[0036] In addition, the following compounds described in WO2018 / 131562A1 can also be used. (R in formula (i) 4 , R 5 and R 6 each represents a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms which may be interrupted by an oxygen atom, a sulfur atom, or an amide bond, and may be the same or different from each other and may be bonded to each other to form a ring structure.

[0037] Examples of the alkyl group having 1 to 20 carbon atoms include linear or branched alkyl groups which may or may not have a substituent, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, an n-octyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-nonyl group, an isononyl group, a p-tert-butylcyclohexyl group, an n-decyl group, an n-dodecylnonyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an eicosyl group. Preferably, it is an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms.

[0038] Examples of alkyl groups having 1 to 20 carbon atoms interrupted by an oxygen atom, a sulfur atom, or an amide bond include those containing the structural unit -CH2-O-, -CH2-S-, -CH2-NHCO-, or -CH2-CONH-. The alkyl group may contain one or more -O-, -S-, -NHCO-, or -CONH- units. Specific examples of alkyl groups having 1 to 20 carbon atoms interrupted by an -O-, -S-, -NHCO-, or -CONH- unit include methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, propylcarbonylamino, butylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, propylaminocarbonyl, butyl ... and the like, and further, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, or octadecyl groups, each of which is substituted with a methoxy, ethoxy, propoxy, butoxy, methylthio, ethylthio, propylthio, butylthio, methylcarbonylamino, ethylcarbonylamino, methylaminocarbonyl, ethylaminocarbonyl, or the like. Preferred are methoxy, ethoxy, methylthio, and ethylthio groups, and more preferred are methoxy and ethoxy groups.

[0039] These solvents have a relatively high boiling point, and are therefore effective in imparting high embedding properties and high planarization properties to the resist underlayer film-forming composition.

[0040] Specific examples of preferred compounds represented by formula (i) are shown below.

[0041] Among the above, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, and Compounds represented by formula (i) are preferably 3-methoxy-N,N-dimethylpropionamide and N,N-dimethylisobutyramide.

[0042] These solvents can be used alone or in combination of two or more. Among these solvents, those having a boiling point of 160°C or higher are preferred, such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, cyclohexanone, 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylisobutyramide, 2,5-dimethylhexane-1,6-diyl diacetate (DAH; cas. 89182-68-3), and 1,6-diacetoxyhexane (cas. 6222-17-9). In particular, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and N,N-dimethylisobutyramide are preferred.

[0043] [Crosslinking Agent Component] The resist underlayer film-forming composition of the present invention may contain a crosslinking agent component. Examples of the crosslinking agent include melamine-based crosslinkers, substituted urea-based crosslinkers, and polymers thereof. A crosslinking agent having at least two crosslink-forming substituents is preferred, such as methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated melamine, methoxymethylated benzoguwanamine, butoxymethylated benzoguwanamine, methoxymethylated urea, butoxymethylated urea, or methoxymethylated thiourea. Condensates of these compounds may also be used.

[0044] In addition, a crosslinking agent having high heat resistance can be used as the crosslinking agent, and a compound containing a crosslink-forming substituent having an aromatic ring (e.g., a benzene ring or a naphthalene ring) in the molecule can be preferably used as the crosslinking agent having high heat resistance.

[0045] This compound may be a compound having a partial structure of the following formula (4), or a polymer or oligomer having a repeating unit of the following formula (5). The above R 11 , R 12 , R 13 , and R 14is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the above-mentioned examples of these alkyl groups can be used. n11 is an integer of 1 to 4, n12 is an integer of 1 to (5-n11), and (n11+n12) is an integer of 2 to 5. n13 is an integer of 1 to 4, n14 is an integer of 0 to (4-n13), and (n13+n14) is an integer of 1 to 4. The number of repeating unit structures used in the oligomers and polymers is in the range of 2 to 100, or 2 to 50.

[0046] Examples of the compounds, polymers and oligomers of formula (4) and formula (5) are shown below.

[0047] The above compounds are available as products of Asahi Organic Chemicals Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above crosslinking agents, the compound of formula (4-24) is available from Asahi Organic Chemicals Co., Ltd. under the trade name TM-BIP-A.

[0048] In addition to the above compounds, compounds having the following structures can also be used as crosslinking agents.

[0049]

[0050] The amount of crosslinking agent added varies depending on the coating solvent used, the base substrate used, the required solution viscosity, the required film shape, etc., but is 0.001 to 80 mass %, preferably 0.01 to 50 mass %, and more preferably 0.05 to 40 mass %, based on the total solids content. These crosslinking agents may cause a crosslinking reaction by self-condensation, but when crosslinkable substituents are present in the above-mentioned reaction product of the present invention, they can cause a crosslinking reaction with these crosslinkable substituents.

[0051] [Acid and / or Acid Generator] The resist underlayer film forming composition of the present invention may contain an acid and / or an acid generator. Examples of the acid include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid.

[0052] The amount of the acid to be used is usually 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 5% by mass, based on the total solid content.

[0053] Examples of the acid generator include thermal acid generators and photoacid generators, such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, pyridinium-4-hydroxybenzenesulfonate, pyridinium-p-toluenesulfonate, pyridinium trifluoromethanesulfonate, N-(4-methoxybenzyl)-N,N-dimethylanilinium triflate, and other organic sulfonic acid alkyl esters.

[0054] Photoacid generators generate acid when the resist is exposed to light. This allows the acidity of the underlayer film to be adjusted. This is one way to match the acidity of the underlayer film to that of the upper layer resist. Adjusting the acidity of the underlayer film also allows for adjustment of the pattern shape of the upper layer resist.

[0055] Examples of the photoacid generator contained in the resist underlayer film-forming composition of the present invention include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0056] Examples of the onium salt compound include iodonium salt compounds such as diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-normal butanesulfonate, diphenyliodonium perfluoro-normal octanesulfonate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, and bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate; and sulfonium salt compounds such as triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

[0057] Examples of the sulfonimide compound include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

[0058] Examples of the disulfonyldiazomethane compound include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0059] The acid generator may be used alone or in combination of two or more kinds. When an acid generator is used, the proportion thereof is 0.01 to 5 parts by mass, or 0.1 to 3 parts by mass, or 0.5 to 1 part by mass, relative to 100 parts by mass of the solid content of the resist underlayer film-forming composition.

[0060] [Other Components] The resist undercoat forming composition of the present invention may contain a surfactant in order to prevent pinholes, striations, etc., and further improve coatability against surface irregularities. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monolaurate; polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monostearate; polyoxyethylene sorbitan monooleate; polyoxyethylene sorbitan trioleate; polyoxyethylene sorbitan monolaurate; polyoxyethylene sorbitan monopalmitate; polyoxyethylene sorbitan monoole ... nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate; EFTOP EF301, EF303, and EF352 (trade names, manufactured by Tochem Products Co., Ltd.); Megafac F171, F173, R-30N, R-40, R-40N, and R-4 Examples of suitable surfactants include fluorine-based surfactants such as 0LM (trade name, manufactured by DIC Corporation), Fluorad FC430, FC431 (trade names, manufactured by Sumitomo 3M Limited), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (trade names, manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). The blending amount of these surfactants is usually 2.0 mass % or less, and preferably 1.0 mass % or less, based on the total solids content of the resist underlayer film composition. These surfactants may be used alone or in combination of two or more. When a surfactant is used, the proportion thereof is 0.0001 to 5 mass parts, or 0.001 to 1 mass part, or 0.01 to 0.5 mass parts, based on 100 mass parts of the solids content of the resist underlayer film-forming composition.

[0061] The resist underlayer film-forming composition of the present invention may contain a light absorber, a rheology modifier, an adhesion promoter, etc. The rheology modifier is effective in improving the fluidity of the underlayer film-forming composition. The adhesion promoter is effective in improving the adhesion between the semiconductor substrate or resist and the underlayer film.

[0062] Examples of the light absorber include commercially available light absorbers described in "Technology and Market of Industrial Dyes" (CMC Publishing) and "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), such as C.I. Disperse Yellow 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114, and 124; C.I. Disperse Orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72, and 73; C.I. C.I. Disperse Red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199 and 210; C.I. Disperse Violet 43; C.I. Disperse Blue 96; C.I. Fluorescent Brightening Agent 112, 135 and 163; C.I. Solvent Orange 2 and 45; C.I. Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49; C.I. Pigment Green 10; C.I. Pigment Brown 2, etc. can be suitably used. The light absorbing agent is usually blended in an amount of 10% by mass or less, preferably 5% by mass or less, based on the total solid content of the resist undercoat forming composition.

[0063] The rheology modifier is added mainly to improve the fluidity of the resist underlayer film-forming composition, particularly in the baking process, to improve the film thickness uniformity of the resist underlayer film and the filling ability of the resist underlayer film-forming composition into holes. Specific examples include phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate. These rheology modifiers are typically blended in an amount of less than 30% by mass based on the total solids content of the resist underlayer film-forming composition.

[0064] The adhesion promoter is added mainly for the purpose of improving the adhesion between the substrate or resist and the resist underlayer film-forming composition, and particularly to prevent peeling of the resist during development. Specific examples include chlorosilanes such as trimethylchlorosilane, dimethylmethylolchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylmethylolethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; methyloltrimethylsilane; and methyloltrimethylsilane. Examples of suitable adhesion aids include silanes such as chlorosilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion aids are typically blended in an amount of less than 5% by mass, and preferably less than 2% by mass, based on the total solids content of the resist undercoat-forming composition.

[0065] The solids content of the resist underlayer film-forming composition according to the present invention is usually 0.1 to 70% by mass, preferably 0.1 to 60% by mass. The solids content is the content of all components of the resist underlayer film-forming composition excluding the solvent. The proportion of the reaction product in the solids content is preferably 1 to 100% by mass, 1 to 99.9% by mass, 50 to 99.9% by mass, 50 to 95% by mass, and 50 to 90% by mass, in that order.

[0066] One measure for evaluating whether a resist underlayer film-forming composition is in a uniform solution state is to observe its passability through a specific microfilter. The resist underlayer film-forming composition of the present invention passes through a microfilter with a pore size of 0.1 μm and exhibits a uniform solution state.

[0067] Examples of the microfilter material include fluorine-based resins such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PE (polyethylene), UPE (ultra-high molecular weight polyethylene), PP (polypropylene), PSF (polysulfone), PES (polyethersulfone), and nylon, but PTFE (polytetrafluoroethylene) is preferred.

[0068] [Methods for Producing Resist Underlayer Film and Semiconductor Device] Hereinafter, methods for producing a resist underlayer film and a semiconductor device using the resist underlayer film-forming composition according to the present invention will be described.

[0069] The resist underlayer film-forming composition of the present invention is applied to a substrate used in the manufacture of a semiconductor device (e.g., a silicon wafer substrate, a silicon / silicon dioxide-coated substrate, a silicon nitride substrate, a glass substrate, an ITO substrate, a polyimide substrate, or a low-dielectric-constant material (low-k material)-coated substrate, etc.) by a suitable application method such as a spinner or a coater, and then baked to form a resist underlayer film. Baking conditions are appropriately selected from a baking temperature of 80°C to 500°C and a baking time of 0.3 to 60 minutes. Preferably, the baking temperature is 150°C to 400°C and the baking time is 0.5 to 2 minutes. The thickness of the underlayer film formed here is, for example, 10 to 1000 nm, or 20 to 500 nm, or 30 to 300 nm, or 50 to 200 nm. The baking atmosphere can be either air or a nitrogen atmosphere.

[0070] Furthermore, an inorganic resist underlayer film (hard mask) can be formed on the organic resist underlayer film according to the present invention. For example, a silicon-containing resist underlayer film (inorganic resist underlayer film)-forming composition described in WO 2009 / 104552 A1 can be formed by spin coating, or a Si-based inorganic material film can be formed by CVD or the like.

[0071] Furthermore, by applying the resist underlayer film-forming composition according to the present invention to a semiconductor substrate having a portion with a step and a portion without a step (a so-called stepped substrate) and baking it, it is possible to form a resist underlayer film in which the step between the portion with a step and the portion without a step is in the range of 3 to 50 nm.

[0072] A resist film, such as a photoresist layer, is then formed on the resist underlayer film. The photoresist layer can be formed by a well-known method, i.e., by coating a photoresist composition solution on the underlayer film and baking it. The photoresist film thickness is, for example, 50 to 10,000 nm, or 100 to 2,000 nm, or 200 to 1,000 nm.

[0073] The photoresist formed on the resist underlayer film is not particularly limited as long as it is sensitive to the light used for exposure. Both negative and positive photoresists can be used. Examples include positive photoresists made of a novolak resin and a 1,2-naphthoquinone diazide sulfonic acid ester; chemically amplified photoresists made of a binder having a group that decomposes in the presence of an acid to increase the alkaline dissolution rate and a photoacid generator; chemically amplified photoresists made of a low molecular weight compound that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, an alkali-soluble binder, and a photoacid generator; and chemically amplified photoresists made of a binder having a group that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, a low molecular weight compound that decomposes in the presence of an acid to increase the alkaline dissolution rate of the photoresist, and a photoacid generator. Examples include APEX-E (trade name) manufactured by Shipley Chemical Co., Ltd., PAR710 (trade name) manufactured by Sumitomo Chemical Co., Ltd., and SEPR430 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. Further examples include those disclosed in Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol. 3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

[0074] Next, a resist pattern is formed by irradiation with light or an electron beam and development. First, exposure is performed through a predetermined mask. Near ultraviolet, far ultraviolet, or extreme ultraviolet (e.g., EUV (wavelength 13.5 nm)) is used for exposure. Specifically, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F2 excimer laser (wavelength 157 nm) can be used. Among these, ArF excimer laser (wavelength 193 nm) and EUV (wavelength 13.5 nm) are preferred. After exposure, post-exposure baking can also be performed as needed. The post-exposure baking is performed under conditions appropriately selected from a heating temperature of 70°C to 150°C and a heating time of 0.3 to 10 minutes.

[0075] In addition, in the present invention, a resist for electron beam lithography can be used instead of a photoresist. Either a negative or positive type electron beam resist can be used. Examples of such resists include chemically amplified resists consisting of an acid generator and a binder having a group that decomposes in the presence of acid to change the alkaline dissolution rate; chemically amplified resists consisting of an alkali-soluble binder, an acid generator, and a low-molecular-weight compound that decomposes in the presence of acid to change the alkaline dissolution rate of the resist; chemically amplified resists consisting of an acid generator, a binder having a group that decomposes in the presence of acid to change the alkaline dissolution rate, and a low-molecular-weight compound that decomposes in the presence of acid to change the alkaline dissolution rate of the resist; non-chemically amplified resists consisting of a binder having a group that decomposes in the presence of an electron beam to change the alkaline dissolution rate; and non-chemically amplified resists consisting of a binder having a moiety that is cleaved by an electron beam to change the alkaline dissolution rate. When using these electron beam resists, resist patterns can be formed in the same manner as when using a photoresist using an electron beam as the irradiation source.

[0076] Next, development is carried out with a developer, whereby, for example, when a positive photoresist is used, the photoresist in the exposed portion is removed, and a photoresist pattern is formed.

[0077] Examples of the developer include aqueous alkaline solutions such as aqueous solutions of alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and choline, and aqueous solutions of amines such as ethanolamine, propylamine and ethylenediamine. Furthermore, surfactants and the like can also be added to these developers. Development conditions are appropriately selected from a temperature of 5 to 50° C. and a time of 10 to 600 seconds.

[0078] Then, the inorganic lower layer film (middle layer) is removed using the photoresist (upper layer) pattern thus formed as a protective film, and then the organic lower layer film (lower layer) is removed using the film consisting of the patterned photoresist and inorganic lower layer film (middle layer) as a protective film. Finally, the semiconductor substrate is processed using the patterned inorganic lower layer film (middle layer) and organic lower layer film (lower layer) as protective films.

[0079] First, the inorganic underlayer film (intermediate layer) in the area where the photoresist has been removed is removed by dry etching to expose the semiconductor substrate. Gases such as tetrafluoromethane (CF), perfluorocyclobutane (CF), perfluoropropane (CF), trifluoromethane, carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride, difluoromethane, nitrogen trifluoride, chlorine trifluoride, chlorine, trichloroborane, and dichloroborane can be used for dry etching of the inorganic underlayer film. A halogen-based gas is preferably used for dry etching of the inorganic underlayer film, and a fluorine-based gas is more preferred. Examples of fluorine-based gases include tetrafluoromethane (CF), perfluorocyclobutane (CF), perfluoropropane (CF), trifluoromethane, and difluoromethane (CHF).

[0080] Thereafter, the organic underlayer film is removed using the patterned photoresist and the inorganic underlayer film as a protective film. The organic underlayer film (underlayer) is preferably removed by dry etching using an oxygen-based gas, because inorganic underlayer films containing a large amount of silicon atoms are difficult to remove by dry etching using an oxygen-based gas.

[0081] Finally, the semiconductor substrate is processed, preferably by dry etching using a fluorine-based gas, such as tetrafluoromethane (CF), perfluorocyclobutane (C4F8), perfluoropropane (C3F8), trifluoromethane, or difluoromethane (CH2F2).

[0082] Furthermore, an organic antireflective coating can be formed on the resist underlayer coating before the formation of the photoresist. The antireflective coating composition used therein is not particularly limited, and any one can be selected from those conventionally used in lithography processes. The antireflective coating can be formed by a conventional method, such as coating with a spinner or coater and baking.

[0083] In the present invention, an organic underlayer film is formed on a substrate, and then an inorganic underlayer film is formed thereon, and a photoresist is then coated on top of that. This narrows the pattern width of the photoresist, and even if a thin layer of photoresist is applied to prevent pattern collapse, the substrate can be processed by selecting an appropriate etching gas. For example, a fluorine-based gas that has a sufficiently high etching rate for the photoresist can be used as an etching gas to process the resist underlayer film, and a fluorine-based gas that has a sufficiently high etching rate for the inorganic underlayer film can be used as an etching gas to process the substrate, and an oxygen-based gas that has a sufficiently high etching rate for the organic underlayer film can be used as an etching gas to process the substrate.

[0084] The resist underlayer film formed from the resist underlayer film-forming composition may also absorb light depending on the wavelength of the light used in the lithography process. In such cases, it can function as an antireflective film that prevents light from being reflected from the substrate. Furthermore, the underlayer film formed from the resist underlayer film-forming composition of the present invention can also function as a hard mask. The underlayer film of the present invention can also be used as a layer for preventing interaction between the substrate and the photoresist, a layer that functions to prevent adverse effects on the substrate of materials used in the photoresist or substances generated during exposure of the photoresist, a layer that functions to prevent diffusion of substances generated from the substrate during heating and baking into an upper photoresist, and a barrier layer for reducing the poisoning effect of the photoresist layer due to a dielectric layer of the semiconductor substrate.

[0085] In addition, an underlayer film formed from the resist underlayer film-forming composition can be applied to a substrate having via holes formed therein for use in a dual damascene process, and can be used as a filling material capable of filling the holes without gaps. It can also be used as a planarizing material for planarizing the surface of an uneven semiconductor substrate.

[0086] The weight average molecular weight and polydispersity shown in Synthesis Example 1 below are based on the results of measurement by gel permeation chromatography (hereinafter abbreviated as GPC in this specification). A GPC device manufactured by Tosoh Corporation was used for the measurement, and the measurement conditions were as follows: GPC column: TSKgel SuperMultipore (registered trademark) Hz-N (Tosoh Corporation) Column temperature: 40°C Solvent: tetrahydrofuran (THF) Flow rate: 0.35 mL / min Standard sample: polystyrene (Tosoh Corporation)

[0087] Synthesis Example 1 Under nitrogen, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (50.00 g, 0.1219 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), 9-fluorenol (88.85 g, 0.4876 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (25.77 g, 0.2682 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a 1000 mL four-neck flask, and propylene glycol 1-monomethyl ether 2-acetate (268.89 g, manufactured by Kanto Chemical Co., Inc.) and 1-methyl-2-pyrrolidone (115.24 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were further charged. The mixture was stirred and heated to 160°C to dissolve the mixture and initiate the reaction. After 24 hours, the mixture was allowed to cool to room temperature and reprecipitated in a mixed solution of methanol (3,600 g, manufactured by Kanto Chemical Co., Inc.) and aqueous ammonia (190 g, manufactured by Kanto Chemical Co., Inc.). The resulting precipitate was filtered and dried in a vacuum dryer at 60°C for 10 hours to obtain 95.5 g of a compound having a structure represented by the following formula (a) (hereinafter abbreviated as BAPP-4F in this specification). The weight average molecular weight Mw of BAPP-4F measured in terms of polystyrene by GPC was 720, and the polydispersity Mw / Mn was 1.10.

[0088] Synthesis Example 2 Under nitrogen, 1,3-bis(4-aminophenoxy)propane (40.00 g, 0.1549 mol, manufactured by Wako Pure Chemical Industries, Ltd.), 9-fluorenol (112.87 g, 0.6194 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (32.74 g, 0.3406 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a 1000 mL four-neck flask, and propylene glycol 1-monomethyl ether 2-acetate (303.17 g, manufactured by Kanto Chemical Co., Inc.) and 1-methyl-2-pyrrolidone (129.93 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were further charged. The mixture was stirred and heated to 160° C. to dissolve the components, thereby initiating the reaction. After 24 hours, the mixture was allowed to cool to room temperature and reprecipitated in a mixed solution of methanol (3,600 g, manufactured by Kanto Chemical Co., Inc.) and aqueous ammonia (190 g, manufactured by Kanto Chemical Co., Inc.). The resulting precipitate was filtered and dried in a vacuum dryer at 60°C for 10 hours to obtain 74.24 g of a compound having a structure represented by the following formula (b) (hereinafter abbreviated as DA-3MG-4F in this specification). The weight average molecular weight Mw of DA-3MG-4F, measured in terms of polystyrene by GPC, was 660, and the polydispersity Mw / Mn was 1.40.

[0089] Synthesis Example 3 Under nitrogen, 1,5-bis(4-aminophenoxy)pentane (40.00 g, 0.1397 mol, manufactured by Wako Pure Chemical Industries, Ltd.), 9-fluorenol (101.80 g, 0.5587 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (29.53 g, 0.3073 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a 1000 mL four-neck flask, and propylene glycol 1-monomethyl ether 2-acetate (279.84 g, manufactured by Kanto Chemical Co., Inc.) and 1-methyl-2-pyrrolidone (119.93 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were further charged. The mixture was stirred and heated to 160° C. to dissolve the mixture and initiate the reaction. After 24 hours, the mixture was allowed to cool to room temperature and reprecipitated in a mixed solution of methanol (3,600 g, manufactured by Kanto Chemical Co., Inc.) and aqueous ammonia (190 g, manufactured by Kanto Chemical Co., Inc.). The resulting precipitate was filtered and dried in a vacuum dryer at 60°C for 10 hours to obtain 77.10 g of a compound having a structure represented by the following formula (c) (hereinafter abbreviated as DA-5MG-4F in this specification). The weight average molecular weight Mw of DA-5MG-4F measured in polystyrene equivalent terms by GPC was 680, and the polydispersity Mw / Mn was 1.40.

[0090] Synthesis Example 4 Under nitrogen, a 1000 mL four-neck flask was charged with 2,2-bis[4-(4-aminophenoxy)phenyl]propane (50.00 g, 0.1219 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), potassium carbonate (134.66 g, 0.974 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and hydroquinone (0.75 g, 0.007 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and further charged with dimethylformamide (500.00 g, manufactured by Kanto Chemical Co., Inc.). The mixture was stirred and heated to 40° C., and then propargyl bromide (101.423 g, 0.853 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise using a dropping funnel to initiate the reaction. After 24 hours, the mixture was allowed to cool to room temperature, and after removing the potassium carbonate residue, toluene (500.00 g, manufactured by Kanto Chemical Co., Ltd.) was added and washed with pure water (500 g). The toluene solution was recovered and evaporated under reduced pressure to obtain 55.3 g of an intermediate product (hereinafter abbreviated as BAPP-PG). Under nitrogen, BAPP-PG (40.00 g, 0.070 mol), 9-fluorenol (25.92 g, 0.142 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (13.67 g, 0.1423 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a 1000 mL four-neck flask, and propylene glycol 1-monomethyl ether 2-acetate (145.7 g, manufactured by Kanto Chemical Co., Ltd.) was further charged, stirred, and heated to 140 °C to dissolve and initiate the reaction. After 24 hours, the mixture was allowed to cool to room temperature and reprecipitated in a mixed solution of methanol (3,600 g, manufactured by Kanto Chemical Co., Inc.) and aqueous ammonia (190 g, manufactured by Kanto Chemical Co., Inc.). The resulting precipitate was filtered and dried in a vacuum dryer at 40°C for 10 hours to obtain 38.3 g of a compound having a structure represented by the following formula (d) (hereinafter abbreviated as BAPP-PG2F in this specification). The weight average molecular weight Mw of BAPP-PG2F measured in polystyrene equivalent terms by GPC was 1,270, and the polydispersity Mw / Mn was 1.30.

[0091] Example 1 A resist underlayer film-forming composition was prepared by dissolving 1.00 g of the compound represented by formula (a) and 0.002 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, a fluorine-based surfactant) in 4.92 g of propylene glycol monomethyl ether and 11.47 g of propylene glycol monomethyl ether acetate.

[0092] Example 2 A resist underlayer film-forming composition was prepared by dissolving 1.00 g of the compound represented by formula (a), 0.20 g of a polymeric crosslinking agent having a structure represented by the following formula (e) as a crosslinking agent (hereinafter abbreviated as TMOM-BPp in this specification), and 0.002 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, fluorine-based surfactant) in 5.88 g of propylene glycol monomethyl ether and 13.72 g of propylene glycol monomethyl ether acetate.

[0093] Example 3 1.00 g of the compound represented by formula (b) and 0.002 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, fluorine-based surfactant) were dissolved in 4.55 g of propylene glycol monomethyl ether and 10.63 g of propylene glycol monomethyl ether acetate to prepare a resist underlayer film-forming composition.

[0094] Example 4 1.00 g of the compound represented by formula (c) and 0.002 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, fluorine-based surfactant) were dissolved in 4.71 g of propylene glycol monomethyl ether and 10.99 g of propylene glycol monomethyl ether acetate to prepare a resist underlayer film-forming composition.

[0095] Example 5 1.00 g of the compound represented by formula (d) and 0.002 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, fluorine-based surfactant) were dissolved in 4.92 g of propylene glycol monomethyl ether and 11.47 g of propylene glycol monomethyl ether acetate to prepare a resist underlayer film-forming composition.

[0096] Comparative Example 1 A resist underlayer film-forming composition was prepared by dissolving 1.00 g of a polymer represented by the following formula (f), 0.20 g of 4,4′-(1-methylethylidyne)bis[2,6-bis[(2-methoxy-1-methylethoxy)methyl]phenol as a crosslinking agent, 0.033 g of pyridinium-p-phenolsulfonate as an acid catalyst, and 0.001 g of a surfactant (manufactured by DIC Corporation, product name: Megafac [product name] R-30N, fluorine-based surfactant) in 4.93 g of propylene glycol monomethyl ether and 11.52 g of propylene glycol monomethyl ether acetate.

[0097] (Elution Test in Photoresist Solvent) The resist underlayer film-forming compositions prepared in Examples 1 to 5 and Comparative Example 1 were each applied to a silicon wafer using a spin coater. The resist underlayer film was baked on a hot plate at 240°C for 1 minute and then at 400°C for 1 minute to form a resist underlayer film (film thickness: 0.10 μm). This resist underlayer film was immersed in propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, solvents used in resists, and it was confirmed that the resist underlayer film was insoluble in these solvents.

[0098] (Coating Test on Stepped Substrate) To evaluate step coverage, a SiO2 substrate on which a trench pattern with a width of 50 nm, a pitch width of 50 nm, and a depth of 200 nm was formed was used. A comparison was made between the coating film thickness of a dense pattern area (DENSE) in which a pattern with a trench width of 100 nm and a pitch of 175 nm was densely formed and an open area (OPEN) 1,400 μm away from the dense pattern area where no pattern was formed. The resist underlayer film-forming compositions of Examples 1-5 and Comparative Example 1 were applied to the substrate in a thickness of 100 nm, and then baked at 240°C for 60 seconds and then at 400°C for 60 seconds. The step coverage of this substrate was observed using a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the planarization ability was evaluated by measuring the film thickness difference between the dense pattern area (pattern area) and the open area (non-pattern area) of the step substrate (the coating step between the dense pattern area and the open area, referred to as Bias). The film thickness and coating step values ​​in each area are shown in Table 1, and SEM photographs of Comparative Example 1 and Example 2 are shown in Figures 1 and 2. In the flattening property evaluation, the smaller the Bias value, the higher the flattening property.

[0099]

[0100] When comparing the coverage on uneven substrates, the results of Examples 1-5 showed that the coating step between the pattern area and the open area was smaller than the results of Comparative Example 1, and therefore it can be said that the resist underlayer films obtained from the resist underlayer film-forming compositions of Examples 1-5 had good planarization properties.

[0101] The present invention can provide a composition that forms a resist underlayer film that does not cause mixing when laminating a photoresist composition or a different resist underlayer film, and that improves pattern filling properties during baking by enhancing the thermal reflow properties of the polymer.

Claims

1. A resist underlayer film forming composition containing a compound represented by the following formula (A) and / or formula (B), and a solvent. (In formula (A), Ar 1 and Ar 2 each independently represent a group consisting of one or more aromatic rings having 6 to 30 carbon atoms which may be substituted by Z 1 , R 1 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkynyl group having 2 to 10 carbon atoms, X represents a single bond or an oxygen atom, and Ar 7 represents the same group as Ar 1 and Ar 2 when X is a single bond, and represents a phenyl group or a naphthyl group when X is an oxygen atom. In formula (B), Ar 3 to Ar 6 have the same definitions as the above Ar 1 and Ar 2 , R 2 and R 3 each have the same definitions as the above R 1 , Y represents a single bond or a divalent group which may be substituted by Z 2 , n1, n2, m1, m2 represent 0 or 1, and not all of n1, n2, m1, m2 become 0 at the same time. The above Z 1 is at least one selected from the group consisting of a halogen atom, a hydroxy group, a cyano group, a methylamino group, a methyl ether group, a cyclic alkyl group, a benzene group, a pyridine group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms and an alkynyl group having 2 to 10 carbon atoms. The above Z 2 is at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms and a fluoroalkyl group having 1 to 10 carbon atoms.) 2. In the formula (A) or formula (B), Ar 1 ~Ar 6 is each independently a group consisting of one or more aromatic rings containing a benzene ring, and the resist underlayer film-forming composition according to claim 1.

3. R in the formula (A) 1 The resist underlayer film-forming composition according to claim 1 or 2, wherein represents a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms.

4. Ar in the formula (B) 3 ~Ar 6 The resist underlayer film-forming composition according to any one of claims 1 to 3, wherein they are the same group.

5. The resist underlayer film-forming composition according to any one of claims 1 to 4, wherein the divalent group in the formula (B) is a group selected from the group consisting of a branched or linear alkylene group having 1 to 15 carbon atoms, a phenylene group, a naphthalene group, an anthracenyl group, a sulfonyl group, a carbonyl group, an ether group, and a thioether group, or a group composed of a combination thereof.

6. The resist underlayer film-forming composition according to claim 5, wherein the divalent group in the formula (B) is any of the groups represented by the following.

7. R in the formula (B) 2 and / or R 3 is a hydrogen atom or an alkynyl group having 2 to 10 carbon atoms, The resist underlayer film forming composition according to any one of claims 1 to 6.

8. The resist underlayer film-forming composition according to any one of claims 1 to 7, further comprising a crosslinking agent.

9. The resist underlayer film-forming composition according to any one of claims 1 to 8, further comprising an acid and / or an acid generator.

10. The resist underlayer film-forming composition according to any one of claims 1 to 9, wherein the solvent is a solvent having a boiling point of 160 °C or higher.

11. A resist underlayer film, characterized in that it is a fired product of a coating film composed of the resist underlayer film-forming composition according to any one of claims 1 to 10.

12. A method for manufacturing a semiconductor device, comprising the steps of forming a resist underlayer film on a semiconductor substrate with the resist underlayer film-forming composition according to any one of claims 1 to 10, forming a resist film thereon, forming a resist pattern by irradiation with light or an electron beam and development, etching the resist underlayer film with the resist pattern, and processing the semiconductor substrate with the patterned resist underlayer film.

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