WO2023162780A1 - Semiconductor substrate production method and composition - Google Patents

Abstract

The purpose of the present invention is to provide: a semiconductor substrate production method using a composition from which a film having excellent etching resistance and heat resistance can be formed; and a composition. This semiconductor substrate production method includes a step in which a resist underlayer film-forming composition is directly or indirectly applied to a substrate, a step in which a resist pattern is formed directly or indirectly on the resist underlayer film formed in the application step, and a step in which etching is performed using the resist pattern as a mask. The resist underlayer film-forming composition contains a solvent and a compound including a boron atom.

Description

Semiconductor substrate manufacturing method and composition

The present invention relates to a method and composition for manufacturing a semiconductor substrate.

In the manufacture of semiconductor devices, for example, a multilayer resist process is used in which a resist pattern is formed by exposing and developing a resist film laminated on a substrate via a resist underlayer film such as an organic underlayer film or a silicon-containing film. It is In this process, the resist underlayer film is etched using this resist pattern as a mask, and the substrate is further etched using the resist underlayer film pattern thus obtained as a mask, thereby forming a desired pattern on the semiconductor substrate (Japanese Laid-Open Patent Publication No. 2004-177668).

Various studies have been conducted on materials used in such a composition for forming a resist underlayer film (see International Publication No. 2011/108365).

JP-A-2004-177668 WO2011/108365

In the multilayer resist process, etching resistance and heat resistance are required for the organic underlayer film as the resist underlayer film.

The present invention has been made based on the above circumstances, and its object is to provide a method for manufacturing a semiconductor substrate using a composition capable of forming a film having excellent etching resistance and heat resistance, and the composition. be.

The present invention, in one embodiment,
a step of directly or indirectly applying a composition for forming a resist underlayer film onto a substrate;
a step of directly or indirectly forming a resist pattern on the resist underlayer film formed by the coating step;
and a step of performing etching using the resist pattern as a mask,
The composition for forming a resist underlayer film is
A compound having a boron atom (hereinafter also referred to as "[A] compound");
The present invention relates to a method for manufacturing a semiconductor substrate containing a solvent (hereinafter also referred to as "[B] solvent").

The present invention, in another embodiment,
a compound having a boron atom;
The present invention relates to a composition for forming a resist underlayer film containing a solvent and

According to the manufacturing method of the semiconductor substrate, it is possible to form a resist underlayer film excellent in etching resistance and heat resistance. According to the composition, a film having excellent etching resistance and heat resistance can be formed. Therefore, these can be suitably used for the manufacture of semiconductor devices, etc., which are expected to be further miniaturized in the future.

The method for manufacturing a semiconductor substrate and the composition according to each embodiment of the present invention will be described in detail below.

<<Manufacturing method of semiconductor substrate>>
The method for producing a semiconductor substrate includes a step of directly or indirectly coating a substrate with a composition for forming a resist underlayer film (hereinafter also referred to as a “coating step”), and a resist underlayer film formed by the coating step. a step of directly or indirectly forming a resist pattern (hereinafter also referred to as a “resist pattern forming step”), and a step of performing etching using the resist pattern as a mask (hereinafter also referred to as an “etching step”).

According to the method for manufacturing a semiconductor substrate, a resist underlayer film having excellent etching resistance and heat resistance can be formed by using the composition described below as a composition for forming a resist underlayer film in the coating step. Therefore, a semiconductor substrate having a good pattern shape can be manufactured with a high yield.

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

The composition and each step used in the method for manufacturing the semiconductor substrate will be described below.

<Composition>
The composition as a composition for forming a resist underlayer film contains [A] compound and [B] solvent. The composition may contain optional ingredients as long as the effects of the present invention are not impaired.

By containing the [A] compound and the [B] solvent, the composition can form a film with excellent etching resistance and heat resistance. Although the reason for this is not clear, it is presumed as follows. The reaction between the boron atoms contained in the [A] compound, which is the main element of the film, and the etching gas causes an effect similar to raising the boiling point or similar to passivation on the etching gas contact surface of the film, and as a result, the film exhibits etching resistance. assumed to be granted. Further, it is speculated that boron atoms in the coating film of the composition combine with oxygen during air baking (during heating) to form a BO bond with a large bond energy, thereby imparting heat resistance. However, it is not limited to these mechanisms and other mechanisms may be employed along with or in place of such mechanisms. Therefore, the composition can be used as a composition for forming a film. More specifically, the composition can be suitably used as a composition for forming a resist underlayer film in a multilayer resist process.

Each component contained in the composition will be described below.

<[A] compound>
The [A] compound is a compound having a boron atom. [A] The compound may have two or more boron atoms. The composition may contain one or more [A] compounds.

[A] The lower limit of the content of boron atoms in the compound is preferably 0.1 atm%, more preferably 0.5 atm%, further preferably 1 atm%, and 1.2 atm%. It is particularly preferred to have The upper limit of the above content is preferably 10 atm %, more preferably 8 atm %, and even more preferably 6 atm %. Thereby, the etching resistance and heat resistance of the obtained film can be improved. The content of boron atoms in the [A] compound is a value calculated from the structural formula of the [A] compound. [A] When the compound is a polymer, it is a value calculated from the repeating unit structure of the polymer and its content.

The [A] compound preferably has an aromatic ring in terms of improving heat resistance. The aromatic ring is preferably an aromatic ring having 5 to 60 ring members, such as benzene ring, naphthalene ring, anthracene ring, phenalene ring, phenanthrene ring, pyrene ring, fluorene ring, perylene ring, coronene ring, trinaphthylene ring, Aromatic hydrocarbon rings such as heptaphene ring, heptacene ring, pyranthrene ring, ovalene ring, hexabenzocoronene ring, furan ring, pyrrole ring, thiophene ring, phosphole ring, pyrazole ring, oxazole ring, isoxazole ring, thiazole ring, imidazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, cinnoline ring, benzofuran ring, isobenzofuran ring, indole ring, isoindole ring, benzothiophene ring, Benzimidazole ring, indazole ring, benzoxazole ring, benzisoxazole ring, benzothiazole ring, aromatic heterocyclic ring such as acridine ring, or combinations thereof. When aromatic rings are combined, the aromatic rings may be bonded to each other with a single bond or a chain structure in addition to the condensed ring structure shown above. The chain structure is preferably a chain hydrocarbon structure and preferably has an unsaturated bond. Among them, the aromatic ring is preferably at least one aromatic hydrocarbon ring selected from the group consisting of benzene ring, naphthalene ring, anthracene ring, phenalene ring, phenanthrene ring, pyrene ring, fluorene ring and perylene ring. Hereinafter, the aromatic ring in the [A] compound refers to the above aromatic ring.

As used herein, the term "number of ring members" refers to the number of atoms forming a ring. For example, the biphenyl ring has 12 ring members, the naphthalene ring has 10 ring members, and the fluorene ring has 13 ring members. A “fused ring structure” refers to a structure in which adjacent rings share one side (two adjacent atoms).

[A] The compound preferably has a partial structure represented by the following formula (i) (hereinafter also referred to as "partial structure (i)"). [A] The compound may have two or more partial structures (i). [A] When the compound has two or more partial structures (i), the multiple partial structures (i) may be the same or different. This facilitates the introduction of boron atoms into the [A] compound, which in turn can improve the etching resistance and heat resistance of the film formed from the composition.

(In formula (i) above, X ¹ and X ² are each independently a carbon atom, a nitrogen atom, or an oxygen atom.)

Preferred combinations of X ¹ and X ² regardless of arrangement are carbon atom and carbon atom, carbon atom and oxygen atom, oxygen atom and oxygen atom, and nitrogen atom and nitrogen atom.

Each atom other than the boron atom in the partial structure (i) is bonded to the portion other than the partial structure in the [A] compound. The same applies to the partial structure including the partial structure (i).

[A] The compound has a partial structure represented by the following formula (i-1) (hereinafter also referred to as "partial structure (i-1)") as an aspect of the partial structure (i). may

(In the above formula (i-1),
Y ¹ and Y ² are each independently -O- or -NR'-. R' is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. When there are multiple R's, the multiple R's are the same or different.
R ¹ and R ² are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ¹ and R ² are combined with Y ¹ and Y ² to which they are bonded It represents a ring structure with 5 to 20 ring members formed together with a boron atom. )

Y ¹ and Y ² are preferably both -O- or both -NR'-.

The monovalent organic group having 1 to 20 carbon atoms represented by R′ includes, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms; Examples thereof include a group having a valent heteroatom-containing group, a group in which some or all of the hydrogen atoms of the above hydrocarbon group are substituted with a monovalent heteroatom-containing group, or a combination thereof.

Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include monovalent linear hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and 6 to 20 monovalent aromatic hydrocarbon groups or combinations thereof.

As used herein, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups and aromatic hydrocarbon groups. This "hydrocarbon group" includes a saturated hydrocarbon group and an unsaturated hydrocarbon group. A "chain hydrocarbon group" means a hydrocarbon group composed only of a chain structure without a ring structure, and includes both a straight chain hydrocarbon group and a branched chain hydrocarbon group. The term "alicyclic hydrocarbon group" means a hydrocarbon group that contains only an alicyclic structure as a ring structure and does not contain an aromatic ring structure, and includes monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic (However, it does not have to consist only of an alicyclic structure, and a part of it may contain a chain structure.). “Aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure (however, it need not consist only of an aromatic ring structure; structure).

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

Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include cycloalkyl groups such as cyclopentyl, cyclobutyl, cyclopentyl and cyclohexyl groups; cyclopropenyl, cyclopentenyl and cyclohexenyl groups. alkenyl group; bridged ring saturated hydrocarbon group such as norbornyl group, adamantyl group and tricyclodecyl group; bridged ring unsaturated hydrocarbon group such as norbornenyl group and tricyclodecenyl group;

Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include phenyl group, tolyl group, naphthyl group, anthracenyl group and pyrenyl group.

Examples of the heteroatom constituting the divalent or monovalent heteroatom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a halogen atom and the like. Halogen atoms include, for example, fluorine, chlorine, bromine and iodine atoms.

The divalent heteroatom-containing group includes, for example, -CO-, -CS-, -NH-, -O-, -S-, groups in which these are combined, and the like.

Examples of monovalent heteroatom-containing groups include a hydroxy group, a sulfanyl group, a cyano group, a nitro group, and a halogen atom.

As the monovalent organic group having 1 to 20 carbon atoms represented by R ¹ and R ² , the above monovalent organic group having 1 to 20 carbon atoms represented by R' can be preferably employed.

R ¹ and R ² are combined and formed together with Y ¹ and Y ² to which they are bonded, and a ring structure having 5 to 20 ring members formed together with a boron atom (hereinafter also referred to as a “boron-containing ring structure”). is not particularly limited as long as it is a ring structure containing -Y ¹ -B(-C)-Y ² - as a partial structure forming Examples of moieties other than -Y ¹ -B(-C)-Y ² - in the boron-containing ring structure include divalent linking groups (one end binds to Y ¹ and the other end binds to Y ² ). be done. As the divalent linking group, a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 20 carbon atoms represented by R′ can be preferably used. When the divalent linking group has another ring structure, the number of ring members of the boron-containing ring structure also includes the number of ring members of this other ring structure.

When both Y ¹ and Y ² are —O—, both R ¹ and R ² are hydrogen atoms, or the above formula (i-1) is a partial structure represented by the following formula (β) is preferred.

(In formula (β) above, R ^b1 and R ^b2 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 1 to 5. R ^b1 and When a plurality of R ^b2 are present, the plurality of R ^b1 and R ^b2 are the same or different.)

As the monovalent organic group having 1 to 20 carbon atoms represented by R ^b1 and R ^b2 , the monovalent organic group having 1 to 20 carbon atoms represented by R′ can be preferably used. Among them, R ^b1 and R ^b2 are preferably a chain hydrocarbon group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group or a propyl group.

p is preferably an integer of 1-4, more preferably an integer of 2-3.

When Y ¹ and Y ² are both —NR′—, R ¹ and R ² are preferably combined with each other to form the above boron-containing ring structure. The moiety other than -Y ¹ -B(-C)-Y ² - in the boron-containing ring structure is preferably the divalent linking group described above, and is preferably a divalent linking group containing a ring structure. more preferred. The ring structure in the divalent linking group forming the boron-containing ring structure is a monovalent alicyclic hydrocarbon having 3 to 20 carbon atoms in the monovalent organic group having 1 to 20 carbon atoms represented by R'. A group obtained by removing one hydrogen atom from a group, a group obtained by removing one hydrogen atom from a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms is preferable, and a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms A group obtained by removing one hydrogen atom from a hydrocarbon group is more preferred, and a benzenediyl group and a naphthalenediyl group are even more preferred.

When both Y ¹ and Y ² are -NR'-, two R' are preferably hydrogen atoms.

[A] The compound has a partial structure represented by the following formula (i-2) (hereinafter also referred to as "partial structure (i-2)") as an aspect of the partial structure (i). may

(In the above formula (i-2),
X ¹ and X ² are synonymous with the above formula (i).
^L2 is a single bond or a divalent linking group.
R ³ is a monovalent organic group having 1 to 20 carbon atoms.
* represents a binding site to a portion other than the partial structure (i-2) in the compound.
m is an integer from 0 to 4; When m is 2 or more, multiple R ³ are the same or different.
n is an integer of 0-2. )

As the divalent linking group represented by L ² , a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 20 carbon atoms represented by R′ can be preferably employed. . L ² is preferably a single bond or an unsaturated chain hydrocarbon group having 2 to 10 carbon atoms, and L ² is preferably a single bond or an ethynediyl group.

As the monovalent organic group having 1 to 20 carbon atoms represented by R ³ , the above monovalent organic group having 1 to 20 carbon atoms represented by R′ can be preferably employed.

m is preferably an integer of 0-3, more preferably an integer of 0-2.

[A] The compound preferably has at least one group selected from the group consisting of a group represented by the following formula (2-1) and a group represented by the following formula (2-2).

(In formulas (2-1) and (2-2), R ⁷ is each independently a divalent organic group having 1 to 20 carbon atoms or a single bond. * is a carbon atom in the [A] compound. is a bond with

The divalent organic group having 1 to 20 carbon atoms represented by R ⁷ is preferably a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 20 carbon atoms represented by R′. can be adopted for

R ⁷ is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms such as a methanediyl group, an ethanediyl group, a phenylene group, or a combination of these with -O-, and a methanediyl group, or a methanediyl group and -O- is more preferred.

In the above formula (i-2), when m is 1 to 3, R ³ is preferably a group represented by the above formula (2-1), and the following formula (2-1-1) is more preferably represented by

* is preferably a bond with a carbon atom in the aromatic ring when the [A] compound has an aromatic ring.

[A] The compound may have a substituent other than the group represented by the above formula (2-1) and the group represented by the above formula (2-2). Examples of substituents include monovalent chain hydrocarbon groups having 1 to 10 carbon atoms; halogen atoms such as fluorine, chlorine, bromine and iodine atoms; alkoxy groups such as methoxy, ethoxy and propoxy; phenoxy group, aryloxy group such as naphthyloxy group, alkoxycarbonyl group such as methoxycarbonyl group and ethoxycarbonyl group, alkoxycarbonyloxy group such as methoxycarbonyloxy group and ethoxycarbonyloxy group, formyl group, acetyl group, propionyl group, Examples include acyl groups such as butyryl groups, cyano groups, nitro groups, and hydroxy groups.

In one embodiment, the [A] compound is preferably a compound represented by the following formula (1-1) (hereinafter also referred to as “compound (1-1)”).

(In the above formula (1-1),
Z ¹ is the above partial structure (i-1). The carbon atom in the partial structure (i-1) corresponds to the carbon atom in X.
X is a (q+r)-valent group containing a substituted or unsubstituted 5 to 60-membered aromatic ring.
R ⁴ is a monovalent group containing an aromatic ring having 5 to 40 ring members.
q is an integer from 1 to 10; When q is 2 or more, multiple Z ^1s are the same or different.
r is an integer from 0 to 10; )

As the aromatic ring having 5 to 60 ring members in the above X, the aromatic ring having 5 to 60 ring members that the compound [A] may have can be suitably employed. The (p+q)-valent group containing a substituted or unsubstituted 5-60 ring-membered aromatic ring represented by X is a group obtained by removing (p+q) hydrogen atoms from the above 5-60 ring-membered aromatic ring. is mentioned. As the substituent when X has a substituent, the group represented by the above formula (2-1), the group represented by the above formula (2-2), and the above-mentioned substituents other than these groups can be suitably employed.

The aromatic ring of X is at least one aromatic hydrocarbon ring selected from the group consisting of benzene, naphthalene, anthracene, phenalene, phenanthrene, pyrene, fluorene, perylene and coronene rings. is preferred.

As the aromatic ring having 5 to 40 ring members for R ⁴ , an aromatic ring corresponding to 5 to 40 ring members among the aromatic rings having 5 to 60 ring members for X can be preferably used. Examples of the monovalent group containing an aromatic ring having 5 to 40 ring members represented by R ⁴ include groups obtained by removing one hydrogen atom from the above aromatic ring having 5 to 40 ring members. The aromatic ring of ^R4 is at least one aromatic hydrocarbon ring selected from the group consisting of benzene ring, naphthalene ring, anthracene ring, phenalene ring, phenanthrene ring, pyrene ring, fluorene ring, perylene ring and coronene ring. is preferred.

Examples of the compound (1-1) include compounds represented by the following formulas (1-1-1) to (1-1-11).

A representative method for synthesizing compound (1-1) is to prepare, for example, a ketone or alkyne-substituted fluorene as a starting material, and allow the cyclization reaction of the ketone moiety or alkyne moiety to proceed in the presence of a catalyst or the like. can be synthesized by reacting this intermediate with an aromatic ring having the partial structure (i). Other structures can also be synthesized by appropriately selecting starting materials, structures of ketone bodies, and the like.

In one embodiment, the [A] compound is preferably a compound represented by the following formula (1-2) (hereinafter also referred to as “compound (1-2)”).

(In formula (1-2),)
Z ² and Z ³ are the above partial structure (i-1). The carbon atoms in the partial structure (i-1) above correspond to the carbon atoms in Ar ¹ and Ar ² . When there are a plurality of ^Z2 and ^Z3 , the plurality of ^Z2 and ^Z3 are the same or different.
Ar ¹ is a (t1+2)-valent group containing a substituted or unsubstituted 5 to 20-membered aromatic ring.
Ar ² is a (t2+1)-valent group containing a substituted or unsubstituted 5 to 20-membered aromatic ring.
s is an integer from 4 to 12;
A plurality of t1 and t2 are each independently an integer of 0-4. However, the sum of multiple t1 and t2 is 1 or more. )

The aromatic ring having 5 to 20 ring members in Ar ¹ and Ar ² is preferably an aromatic ring corresponding to 5 to 20 ring members among the above aromatic rings having 5 to 60 ring members that the compound [A] may have. can be adopted for The (t1+2)-valent group represented by Ar ¹ includes groups obtained by removing (t1+2) hydrogen atoms from the above aromatic ring having 5 to 20 ring members. The (t2+1)-valent group represented by Ar ² includes a group obtained by removing (t2+1) hydrogen atoms from the above aromatic ring having 5 to 20 ring members. The aromatic ring having 5 to 20 ring members in Ar ¹ and Ar ² is preferably a benzene ring or a naphthalene ring. When Ar ¹ and Ar ² have substituents, the substituents include groups represented by the above formula (2-1), groups represented by the above formula (2-2), and other substituents. The substituents listed above can be suitably employed.

s is preferably an integer of 4-10, more preferably an integer of 4-8, even more preferably an integer of 4-6.

A plurality of t1 and t2 are each independently preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 0 or 1. t1 is preferably zero and t2 is preferably one.

Examples of the compound (1-2) include compounds represented by the following formulas (1-2-1) to (1-2-6).

As a method for synthesizing the compound (1-2), typically, it can be synthesized by a condensation reaction between, for example, an aromatic alcohol as a starting material and an aromatic ring aldehyde having the partial structure (i). After that, a modification reaction of the phenolic hydroxyl group of the aromatic alcohol may be performed. Other structures can also be synthesized by appropriately selecting the structures of starting materials such as aromatic alcohols and aromatic ring aldehydes.

In one embodiment, the [A] compound is a compound represented by the following formula (1-3) or (1-4) (hereinafter also referred to as "compound (1-3)" etc.). preferable.

(In formulas (1-3) and (1-4),
Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ²¹ , Ar ²² and Ar ²³ are each independently a substituted or unsubstituted monovalent group containing an aromatic ring having 5 to 20 ring members.
L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , L ²¹ , L ²² and L ²³ are each independently a single bond or a divalent linking group. )

As the aromatic ring having 5 to 20 ring members in Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ²¹ , Ar ²² and Ar ²³ , the aromatic ring having 5 to 60 ring members which the compound [A] may have Of the rings, aromatic rings having 5 to 20 ring members can be preferably used. The monovalent groups represented by Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ²¹ , Ar ²² and Ar ²³ are groups obtained by removing one hydrogen atom from the above aromatic ring having 5 to 20 ring members. is mentioned. When Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ²¹ , Ar ²² and Ar ²³ have a substituent, the substituents include the group represented by the above formula (2-1), the above formula (2- The group represented by 2) and the above-described substituents other than these can be suitably employed. Ar ¹¹ , Ar ¹² , Ar ¹³ , Ar ¹⁴ , Ar ²¹ , Ar ²² and Ar ²³ are each independently preferably a phenyl group or a naphthyl group.

As the divalent linking group represented by L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , L ²¹ , L ²² and L ²³ , the divalent linking group represented by L ² in formula (i-2) above groups can be suitably employed.

Examples of the compounds (1-3) and (1-4) include the following formulas (1-3-1) to (1-3-4) and the following formulas (1-4-1) to (1-4- 3), and the like.

A representative method for synthesizing compounds (1-3) and (1-4) is to react a (halogen-substituted) aromatic ring or an ethynyl group-containing aromatic ring and a halogen-substituted borane as starting materials in the presence of organic lithium. It can be synthesized by reacting with Other structures can also be synthesized by appropriately selecting the structure of the starting material (halogen-substituted) aromatic ring or ethynyl group-containing aromatic ring.

In one embodiment, the [A] compound is preferably a novolac-type polymer (hereinafter also referred to as "polymer (1)") containing two or more repeating units having partial structure (i). . Polymer (1) is preferably represented by the following formula (1-5).

(In formula (1-5),)
Z ⁴ and Z ⁵ are the above partial structure (i-1). The carbon atoms in partial structure (i-1) above correspond to the carbon atoms in Ar ³ and Ar ⁴ . When multiple Z ⁴ and Z ⁵ are present, multiple Z ⁴ and Z ⁵ are the same or different from each other.
Ar ³ is a (u1+2)-valent group containing a substituted or unsubstituted 5 to 20-membered aromatic ring.
Ar ⁴ is a (u2+1) valent group containing a substituted or unsubstituted aromatic ring having 5 to 20 ring members.
u1 and u2 are each independently an integer of 0-4. However, the sum of u1 and u2 is 1 or more. )

The aromatic ring having 5 to 20 ring members in Ar ³ and Ar ⁴ is preferably an aromatic ring corresponding to 5 to 20 ring members among the aromatic rings having 5 to 60 ring members that the compound [A] may have. can be adopted for The (u1+2)-valent group represented by Ar ³ includes groups obtained by removing (u1+2) hydrogen atoms from the above aromatic ring having 5 to 20 ring members. The (u2+1)-valent group represented by Ar ⁴ includes groups obtained by removing (u2+1) hydrogen atoms from the above aromatic ring having 5 to 20 ring members. The aromatic ring having 5 to 20 ring members in Ar ³ and Ar ⁴ is preferably a benzene ring or a naphthalene ring. The substituents when Ar ³ and Ar ⁴ have a substituent include the group represented by the above formula (2-1), the group represented by the above formula (2-2), and substituents other than these The substituents listed above can be suitably employed.

u1 and u2 are each independently preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and even more preferably 0 or 1. u1 is preferably 0 and u2 is preferably 1;

Examples of the polymer (1) include compounds represented by the following formulas (1-5-1) to (1-5-12).

A representative method for producing polymer (1) includes an aromatic ring (having partial structure (i)) as a precursor giving Ar ³ of formula (1-5) above, and A novolac-type polymer (1) can be produced by acid addition condensation with an aldehyde or an aldehyde derivative (having partial structure (i)) as a precursor giving Ar ⁶ in 5). Other structures can also be synthesized by appropriately selecting the structure of the aromatic ring of the starting material.

In one embodiment, the [A] compound is a polymer different from the above polymer (1) (hereinafter also referred to as "polymer (2)"), which contains two or more repeating units having partial structure (i). ) is preferred. Polymer (2) is preferably represented by the following formula (1-6).

(In formula (1-6),
R ⁶¹ and R ⁶² are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms.
L ³¹ and L ³² are each independently a single bond or a divalent linking group.
Ar ⁵ is a monovalent group containing a substituted or unsubstituted 5- to 20-membered aromatic ring.
Ar ⁶ is a (v+1) valent group containing a substituted or unsubstituted 5- to 20-membered aromatic ring.
^Z6 is the above partial structure (i-1). The carbon atoms in partial structure (i-1) above correspond to the carbon atoms in Ar ⁶ . When multiple Z ⁶ are present, the multiple Z ⁶ are the same or different.
v is an integer from 1 to 4; )

As the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁶¹ and R ⁶² , a monovalent hydrocarbon group having 1 to 20 carbon atoms in R' of the above formula (i) is preferably employed. be able to. When R ⁶¹ and R ⁶² have substituents, the substituents include groups represented by the above formula (2-1), groups represented by the above formula (2-2), and other substituents. The substituents listed above can be suitably employed. R ⁶¹ and R ⁶² are each independently preferably a hydrogen atom or a methyl group.

As the divalent linking group represented by L ³¹ and L ³² , the divalent linking group represented by L ² in formula (i-2) above can be preferably employed. Among them, L ³¹ and L ³² are each independently preferably a single bond or -COO- ^* . * is the binding site on the Ar ⁵ and Ar ⁶ side.

The aromatic ring having 5 to 20 ring members in Ar ⁵ and Ar ⁶ is preferably an aromatic ring corresponding to 5 to 20 ring members among the above 5 to 60 ring member aromatic rings that the compound [A] may have. can be adopted for The monovalent group represented by Ar ⁵ includes groups obtained by removing one hydrogen atom from the above aromatic ring having 5 to 20 ring members. The (v+1)-valent group represented by Ar ⁶ includes groups obtained by removing (v+1) hydrogen atoms from the above aromatic ring having 5 to 20 ring members. The aromatic ring having 5 to 20 ring members in Ar ⁵ and Ar ⁶ is preferably a benzene ring, a naphthalene ring, a pyrene ring or a biphenyl ring. The substituents when Ar ⁵ and Ar ⁶ have a substituent include the group represented by the above formula (2-1), the group represented by the above formula (2-2), and substituents other than these The substituents listed above can be suitably employed.

v is preferably an integer of 1 to 3, preferably 1 or 2.

Examples of the polymer (2) include compounds represented by the following formulas (1-6-1) to (1-6-8).

Polymer (2) can typically be synthesized by radical polymerization. In this case, monomers that provide each structural unit can be synthesized by polymerizing in a suitable solvent using a radical polymerization initiator or the like.

The lower limit of the content of the [A] compound in the composition is preferably 2% by mass, more preferably 4% by mass, more preferably 6% by mass in the total mass of the [A] compound and [B] solvent, 8% by weight is particularly preferred. The upper limit of the content ratio is preferably 30% by mass, more preferably 25% by mass, still more preferably 20% by mass, and particularly preferably 18% by mass, based on the total mass of the [A] compound and [B] solvent.

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

[B] Solvents include, for example, hydrocarbon solvents, ester solvents, alcohol solvents, ketone solvents, ether solvents, nitrogen-containing solvents, and the like. [B] A solvent can be used individually by 1 type or in combination of 2 or more types.

Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-pentane, n-hexane and cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene and xylene.

Examples of ester solvents include carbonate solvents such as diethyl carbonate, acetic acid monoester solvents such as methyl acetate and ethyl acetate, lactone solvents such as γ-butyrolactone, diethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate. Valued alcohol partial ether carboxylate solvents, lactate ester solvents such as methyl lactate and ethyl lactate, and the like are included.

Examples of alcoholic solvents include monoalcoholic solvents such as methanol, ethanol and n-propanol, and polyhydric alcoholic solvents such as ethylene glycol and 1,2-propylene glycol.

Examples of ketone solvents include chain ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketone solvents such as cyclohexanone.

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

Examples of nitrogen-containing solvents include linear nitrogen-containing solvents such as N,N-dimethylacetamide and cyclic nitrogen-containing solvents such as N-methylpyrrolidone.

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

The lower limit of the content of the [B] solvent in the composition is preferably 50% by mass, more preferably 60% by mass, and even more preferably 70% by mass. The upper limit of the content ratio is preferably 99.9% by mass, more preferably 99% by mass, and even more preferably 95% by mass.

[Optional component]
The composition may contain optional ingredients as long as they do not impair the effects of the present invention. Examples of optional components include a compound corresponding to the structure obtained by removing the partial structure (i) from the [A] compound, an acid generator, a cross-linking agent, a surfactant, and the like. An arbitrary component can be used individually by 1 type or in combination of 2 or more types. The content ratio of the optional component in the composition can be appropriately determined according to the type of the optional component.

[Method for preparing composition]
The composition is prepared by mixing the [A] compound, [B] solvent, and optional ingredients in a predetermined ratio as necessary, and preferably filtering the resulting mixture through a membrane filter having a pore size of 0.5 μm or less. can be prepared by

[Coating process]
In this step, the resist underlayer film-forming composition is applied directly or indirectly onto the substrate. In this step, the composition described above is used as the composition for forming the resist underlayer film.

The method of coating the composition for forming a resist underlayer film is not particularly limited, and can be carried out by an appropriate method such as spin coating, casting coating, roll coating, or the like. As a result, a coating film is formed, and [B] a resist underlayer film is formed by volatilization of the solvent.

Examples of the substrate include metal or semi-metal substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, among which silicon substrates are preferred. . The substrate may be a substrate on which a silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, or the like is formed.

Examples of the case of indirectly applying the composition for forming a resist underlayer film onto a substrate include the case of applying the composition for forming a resist underlayer film onto a silicon-containing film formed on the substrate, which will be described later.

[Heating process]
In this step, the coating film formed by the coating step is heated. The heating of the coating promotes the formation of the resist underlayer film. More specifically, heating the coating film promotes volatilization of the [B] solvent.

The coating film may be heated in an air atmosphere or in a nitrogen atmosphere. The lower limit of the heating temperature is preferably 300°C, more preferably 320°C, and even more preferably 350°C. The upper limit of the heating temperature is preferably 600°C, more preferably 550°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds. The upper limit of the time is preferably 1,200 seconds, more preferably 600 seconds.

Note that the resist underlayer film may be exposed after the coating step. After the coating step, the resist underlayer film may be exposed to plasma. After the coating step, ions may be implanted into the resist underlayer film. Exposure of the resist underlayer film improves the etching resistance of the resist underlayer film. Exposure of the resist underlayer film to plasma improves the etching resistance of the resist underlayer film. Ion implantation into the resist underlayer film improves the etching resistance of the resist underlayer film.

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

　As a method of exposing the resist underlayer film to plasma, for example, a direct method by placing the substrate in each gas atmosphere and discharging plasma can be mentioned. As conditions for plasma exposure, the normal gas flow rate is 50 cc/min or more and 100 cc/min or less, and the power supply is 100 W or more and 1,500 W or less.

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

Plasma is generated, for example, in a mixed gas atmosphere of H ₂ gas and Ar gas. In addition to H ₂ gas and Ar gas, a carbon-containing gas such as CF ₄ gas or CH ₄ gas may be introduced. Instead of one or both of _H2 gas and Ar gas, _CF4 gas, _NF3 gas _{, CHF3} gas _{, CO2} gas, _CH2F2 gas, _CH4 gas and _C4F8 gas At least one of them may be introduced.

The ion implantation into the resist underlayer film injects the dopant into the resist underlayer film. Dopants may be selected from the group consisting of boron, carbon, nitrogen, phosphorous, arsenic, aluminum, and tungsten. Implant energies used to voltage the dopants range from about 0.5 keV to 60 keV, depending on the type of dopant used and the depth of implantation desired.

The lower limit to the average thickness of the resist underlayer film to be formed is preferably 30 nm, more preferably 50 nm, and even more preferably 100 nm. The upper limit of the average thickness is preferably 3,000 nm, more preferably 2,000 nm, and even more preferably 500 nm. The method for measuring the average thickness is described in Examples.

[Silicon-containing film forming step]
In this step, a silicon-containing film is formed directly or indirectly on the resist underlayer film formed in the coating step or the heating step. Examples of the case where the silicon-containing film is formed indirectly on the resist underlayer film include, for example, the case where a surface modification film of the resist underlayer film is formed on the resist underlayer film. The surface modified film of the resist underlayer film is, for example, a film having a contact angle with water different from that of the resist underlayer film.

A silicon-containing film can be formed by coating a silicon-containing film-forming composition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like. As a method of forming a silicon-containing film by coating a silicon-containing film-forming composition, for example, a coating film formed by directly or indirectly coating a silicon-containing film-forming composition on the resist underlayer film is formed. , a method of curing by exposure and/or heating, and the like. Commercially available products of the silicon-containing film-forming composition include, for example, "NFC SOG01", "NFC SOG04", and "NFC SOG080" (manufactured by JSR Corporation). Silicon oxide films, silicon nitride films, silicon oxynitride films, and amorphous silicon films can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

Examples of the radiation used for the exposure include visible light, ultraviolet rays, far ultraviolet rays, X-rays, electromagnetic waves such as γ-rays, and particle beams such as electron beams, molecular beams, and ion beams.

The lower limit of the temperature when heating the coating film is preferably 90°C, more preferably 150°C, and even more preferably 200°C. The upper limit of the temperature is preferably 550°C, more preferably 450°C, and even more preferably 300°C.

The lower limit of the average thickness of the silicon-containing film is preferably 1 nm, more preferably 10 nm, and even more preferably 20 nm. The upper limit is preferably 20,000 nm, more preferably 1,000 nm, even more preferably 100 nm. The average thickness of the silicon-containing film is a value measured using the spectroscopic ellipsometer as in the case of the average thickness of the resist underlayer film.

[Resist pattern forming step]
In this step, a resist pattern is formed directly or indirectly on the resist underlayer film. Examples of the method for performing this step include a method using a resist composition, a method using a nanoimprint method, a method using a self-assembled composition, and the like. Examples of forming a resist pattern indirectly on the resist underlayer film include forming a resist pattern on the silicon-containing film.

Examples of the resist composition include a positive-type or negative-type chemically amplified resist composition containing a radiation-sensitive acid generator, a positive-type resist composition containing an alkali-soluble resin and a quinonediazide-based photosensitizer, an alkali-soluble Examples include a negative resist composition containing a resin and a cross-linking agent.

Examples of the coating method of the resist composition include a spin coating method and the like. The pre-baking temperature and time can be appropriately adjusted depending on the type of resist composition used.

Next, the resist film thus formed is exposed by selective radiation irradiation. The radiation used for exposure can be appropriately selected according to the type of radiation-sensitive acid generator used in the resist composition, and examples thereof include visible light, ultraviolet light, deep ultraviolet light, X-rays, and γ-rays. Examples include electromagnetic waves, electron beams, molecular beams, and particle beams such as ion beams. Among these, far ultraviolet rays are preferred, and KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), _F2 excimer laser light (wavelength 157 nm), _Kr2 excimer laser light (wavelength 147 nm), ArKr excimer Laser light (wavelength: 134 nm) or extreme ultraviolet rays (wavelength: 13.5 nm, etc., hereinafter also referred to as "EUV") are more preferred, and KrF excimer laser light, ArF excimer laser light, or EUV is even more preferred.

After the above exposure, post-baking can be performed to improve the resolution, pattern profile, developability, and the like. The temperature and time of this post-baking can be appropriately determined according to the type of resist composition used.

Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be either alkali development or organic solvent development. As the developer, in the case of alkali development, basic aqueous solutions such as ammonia, triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, etc. can be used. Suitable amounts of water-soluble organic solvents such as alcohols such as methanol and ethanol, surfactants, and the like can also be added to these basic aqueous solutions. In the case of organic solvent development, the developer includes, for example, various organic solvents exemplified as the [B] solvent of the composition.

A predetermined resist pattern is formed by washing and drying after development with the developer.

[Etching process]
In this step, etching is performed using the resist pattern as a mask. Etching may be performed once or multiple times, that is, etching may be performed sequentially using a pattern obtained by etching as a mask. Multiple times are preferable from the viewpoint of obtaining a pattern with a better shape. When etching is performed multiple times, for example, the silicon-containing film, the resist underlayer film, and the substrate are sequentially etched. Etching methods include dry etching, wet etching, and the like. Dry etching is preferable from the viewpoint of improving the pattern shape of the substrate. For this dry etching, gas plasma such as oxygen plasma is used. A semiconductor substrate having a predetermined pattern is obtained by the etching.

Dry etching can be performed using, for example, a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected according to the mask pattern, the elemental composition of the film to be etched, etc. Examples include CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ and SF _{6 .} Fluorine-based gases, chlorine-based gases such as Cl ₂ and BCl ₃ , oxygen-based gases such as O ₂ , O ₃ and H 2 O, H ₂ , NH ₃ , CO, CO _{2 ,} CH ₄ , C ₂ H ₂ , C _2H4 , _C2H6 , _C3H4 , _{C3H6 , C3H8 ,} HF _, HI, HBr, HCl, NO, _BCl3 and _{other reducing} gases _; He, _N2 , Ar and other Inert gas etc. are mentioned. These gases can also be mixed and used. When etching a substrate using the pattern of the resist underlayer film as a mask, a fluorine-based gas is usually used.

"Composition"
The composition contains [A] compound and [B] solvent. As the composition, the composition used in the method for manufacturing a semiconductor substrate can be suitably employed.

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

[Weight average molecular weight (Mw)]
The Mw of the polymer is determined using Tosoh Corporation GPC columns (2 "G2000HXL", 1 "G3000HXL", and 1 "G4000HXL"), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column Temperature: Measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under analysis conditions of 40°C.

[Average thickness of resist underlayer film]
The average thickness of the resist underlayer film was measured at arbitrary intervals of 5 cm including the center of the resist underlayer film formed on a 12-inch silicon wafer (substrate) using a spectroscopic ellipsometer ("M2000D" manufactured by JA WOOLLAM). The film thickness was measured at nine points, and the average value of the film thicknesses was obtained as a calculated value.

[Synthesis Example 1] (Synthesis of Compound (A-1))
In a reaction vessel under nitrogen atmosphere, 5.0 g of 1,3-benzenediol, 10.5 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, and 77 ethanol were added. .7 g was charged and dissolved at room temperature. To the obtained solution, 13.4 g of concentrated sulfuric acid was added dropwise over 1 hour, then the solution temperature was raised to 80°C and stirred for 7 hours, and the solution temperature was cooled to 30°C. After that, the precipitated reddish-brown solid matter was recovered by filtration to obtain a solid matter serving as a precursor.

Next, 7.8 g of the precursor obtained above, 31.2 g of 4-methyl-2-pentanone, 15.6 g of methanol, and 19.7 g of a 25% by mass tetramethylammonium hydroxide aqueous solution were charged into a reactor under a nitrogen atmosphere, Dissolved at room temperature. After that, the temperature was raised to 50° C., 6.4 g of propargyl bromide was added dropwise over 30 minutes, and the mixture was stirred at 50° C. for 6 hours. Reprecipitated. The precipitate was collected with filter paper and dried to obtain a compound (A-1) represented by the following formula (A-1).

[Synthesis Example 2] (Synthesis of compound (a-1))
20.0 g of 2-acetylfluorene and 20.0 g of m-xylene were placed in a reactor under a nitrogen atmosphere and dissolved at 110.degree. Next, 3.1 g of dodecylbenzenesulfonic acid was added, heated to 140° C. and stirred for 16 hours. After diluting the reaction solution by adding 80.0 g of xylene, it was cooled to 50° C. and mixed with 500.0 g of methanol. and reprecipitated. The resulting precipitate was collected with filter paper and dried to obtain the following compound (a-1).

[Synthesis Example 3] (Synthesis of compound (A-2))
8.0 g of the above compound (a-1), 6.9 g of 3-formylphenylboronic acid, 7.0 g of diazabicycloundecene and 149.4 g of N,N-dimethylacetamide were added to a reaction vessel under a nitrogen atmosphere. C. for 12 hours, cooled to 30.degree. C., and poured into 500.0 g of methanol for reprecipitation. The precipitate was collected with filter paper and dried to obtain a compound (A-2) represented by the following formula (A-2).

[Synthesis Example 4] (Synthesis of compound (A-3))
6.9 g of 3-formylphenylboronic acid, 10.7 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, and 149.4 g of N,N-dimethylacetamide A compound (A-3) represented by the following formula (A-3) was obtained in the same manner as in Synthesis Example 3, except that 187.4 g of N,N-dimethylacetamide was used.

[Synthesis Example 5] (Synthesis of compound (A-4))
20.0 g of 2-phenylethynylfluorene and 200 g of 1,4-dioxane were placed in a reactor under a nitrogen atmosphere and dissolved at 50.degree. Then, 1.28 g of octacarbonyl dicobalt was added, heated to 110° C., stirred for 12 hours, cooled to room temperature, and 600 g of methanol and 60.0 g of water were added to obtain a precipitate. The resulting precipitate was collected with a filter paper, washed with a large amount of methanol, and dried to obtain a solid precursor.

Next, 8.0 g of the precursor obtained above, 5.0 g of 3-formylphenylboronic acid, 5.0 g of diazabicycloundecene, and 129.5 g of N,N-dimethylacetamide were added to a reaction vessel under a nitrogen atmosphere, After stirring at 130° C. for 12 hours and cooling to 30° C., the mixture was poured into 400.0 g of methanol for reprecipitation. The precipitate was collected with filter paper to obtain a compound (A-4) represented by the following formula (A-4).

[Synthesis Example 6] (Synthesis of Compound (A-5))
In a reaction vessel under a nitrogen atmosphere, 8.0 g of 2,7-diethynylfluorene, 12.1 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, dia. 8.0 g of zabicycloundecene and 201.3 g of N,N-dimethylacetamide were added, stirred at 130° C. for 8 hours, cooled to 30° C., and poured into 600.0 g of methanol for reprecipitation. The precipitate was collected with filter paper and dried to obtain a compound (A-5) represented by the following formula (A-5).

[Synthesis Example 7] (Synthesis of compound (A-6))
Under nitrogen atmosphere, 6.2 g of ethynylbenzene and 36.0 g of tetrahydrofuran were added to the reactor and cooled to -78°C. The mixture was stirred for 30 minutes. Then, 5.0 g of tribromoborane was added dropwise and stirred at −78° C. for 1 hour, heated to 0° C. and stirred for 5 hours. ) slowly added the mixed solvent. The resulting reaction solution was concentrated under reduced pressure to 25.0 g, and separated and extracted with 30.0 g of ultrapure water to remove the aqueous layer. Further, 50.0 g of heptane was added for liquid-liquid extraction, and the lower layer was recovered and concentrated under reduced pressure to obtain a compound (A-6) represented by the following formula (A-6).

[Synthesis Example 8] (Synthesis of Compound (A-7))
The following formula (A-7) was obtained in the same manner as in Synthesis Example 7, except that 6.2 g of ethynylbenzene was changed to 13.2 g of 2-bromo-1,3-dimethoxybenzene and 36.0 g of tetrahydrofuran was changed to 137.8 g of tetrahydrofuran. The represented compound (A-7) was obtained.

[Synthesis Example 9] (Synthesis of compound (A-8))
Represented by the following formula (A-8) in the same manner as in Synthesis Example 7, except that 6.2 g of ethynylbenzene was changed to 11.1 g of 1-bromo-4-vinylbenzene and 36.0 g of tetrahydrofuran was changed to 121.4 g of tetrahydrofuran. A compound (A-8) was obtained.

[Synthesis Example 10] (Synthesis of Compound (A-9))
8.0 g of 1-hydroxypyrene, 10.2 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, and p-toluenesulfone were placed in a reaction vessel under a nitrogen atmosphere. 4.4 g of acid monohydrate and 36.4 g of 1-butanol were added, stirred at 110° C. for 16 hours, cooled to 30° C., and poured into 100.0 g of methanol for reprecipitation. The precipitate was collected with filter paper and dried to obtain a precursor solid.

Next, 5.0 g of the precursor obtained above, 20.0 g of 4-methyl-2-pentanone, 10.0 g of methanol, and 6.3 g of a 25% by mass tetramethylammonium hydroxide aqueous solution were charged into a reactor under a nitrogen atmosphere, Dissolved at room temperature. After that, the temperature was raised to 50°C, and 2.1 g of propargyl bromide was added dropwise over 30 minutes. Reprecipitated. The precipitate was collected with filter paper and dried to obtain a compound (A-9) represented by the following formula (A-9). Mw of the obtained compound (A-9) was 4,500.

[Synthesis Example 11] (Synthesis of compound (A-10))
To 10.2 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, 6.6 g of 3-formylphenyl boronic acid, 36.4 g of 1-butanol to 1- A compound (A-10) represented by the following formula (A-10) was obtained in the same manner as the precursor synthesis of Synthesis Example 10, except that 29.2 g of butanol was used. Mw of the obtained compound (A-10) was 3,200.

[Synthesis Example 12] (Synthesis of Compound (A-11))
Precursor synthesis of Synthesis Example 10 except that 8.0 g of 1-hydroxypyrene was changed to 12.9 g of 9,9-bis(4-hydroxyphenyl)fluorene and 36.4 g of 1-butanol was changed to 46.1 g of 1-butanol. A compound (A-11) represented by the following formula (A-11) was obtained in the same manner as above. Mw of the obtained compound (A-11) was 4,000.

[Synthesis Example 13] (Synthesis of compound (A-12))
To 8.0 g of 1-hydroxypyrene, 10.0 g of 3-hydroxyphenylboronic acid, 10.2 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, 4 -Phenylbenzaldehyde 15.9g, p-toluenesulfonic acid monohydrate 4.4g was changed to p-toluenesulfonic acid monohydrate 6.9g, 1-butanol 36.4g was changed to 1-butanol 51.2g obtained a solid precursor in the same manner as in Synthesis Example 10.

Next, 5.0 g of the precursor obtained above, 15.0 g of 4-methyl-2-pentanone, 7.5 g of methanol, and 19.9 g of a 25% by mass tetramethylammonium hydroxide aqueous solution were charged into a reactor under a nitrogen atmosphere, Dissolved at room temperature. After that, the temperature was raised to 50°C, 6.5 g of propargyl bromide was added dropwise over 30 minutes, and the mixture was stirred at 50°C for 6 hours. Reprecipitated. The precipitate was collected with filter paper and dried to obtain a compound (A-12) represented by the following formula (A-12). Mw of the obtained compound (A-12) was 4,700.

[Synthesis Example 14] (Synthesis of compound (A-13))
8.0 g of 1-hydroxypyrene, 10.0 g of 3-hydroxyphenylboronic acid, 10.2 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde, - 20.0 g of pyrene carbaldehyde, 4.4 g of p-toluenesulfonic acid monohydrate was changed to 6.9 g of p-toluenesulfonic acid monohydrate, and 36.4 g of 1-butanol was changed to 60.1 g of 1-butanol. Except for this, in the same manner as in Synthesis Example 10, a solid material serving as a precursor was obtained.

Next, 5.0 g of the precursor obtained above, 15.0 g of 4-methyl-2-pentanone, 7.5 g of methanol, and 17.1 g of a 25% by mass tetramethylammonium hydroxide aqueous solution were charged into a reactor under a nitrogen atmosphere, Dissolved at room temperature. After that, the temperature was raised to 50°C, and 5.6 g of propargyl bromide was added dropwise over 30 minutes. Reprecipitated. The precipitate was collected with filter paper and dried to obtain a compound (A-13) represented by the following formula (A-13). Mw of the obtained compound (A-13) was 4,500.

[Synthesis Example 15] (Synthesis of compound (a-2))
Under a nitrogen atmosphere, 5.0 g of 3-hydroxyphenylboronic acid, 7.8 g of 1,8-naphthalenediamine and 72.5 g of tetrahydrofuran were added to a reaction vessel, stirred at 60°C for 24 hours, and cooled to 30°C to obtain The resulting reaction solution was concentrated under reduced pressure and purified by silica gel column chromatography to obtain compound (a-2).

[Synthesis Example 16] (Synthesis of compound (A-14))
8.0 g of 1-hydroxypyrene was added to 10.0 g of (a-2), and 10.2 g of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde was added to 1- Except for changing 10.6 g of pyrenecarbaldehyde, 4.4 g of p-toluenesulfonic acid monohydrate to 3.7 g of p-toluenesulfonic acid monohydrate, and 36.4 g of 1-butanol to 41.2 g of 1-butanol. obtained a solid precursor in the same manner as in Synthesis Example 10.

Next, 5.0 g of the precursor obtained above, 15.0 g of 4-methyl-2-pentanone, 7.5 g of methanol, and 12.7 g of a 25% by mass tetramethylammonium hydroxide aqueous solution were charged into a reactor under a nitrogen atmosphere, Dissolved at room temperature. After that, the temperature was raised to 50° C., 4.2 g of propargyl bromide was added dropwise over 30 minutes, the mixture was stirred at 50° C. for 6 hours, cooled to 30° C., the aqueous layer was removed, and the mixture was added to 60.0 g of methanol. Reprecipitated. The precipitate was collected with filter paper and dried to obtain a compound (A-14) represented by the following formula (A-14). Mw of the obtained compound (A-14) was 4,800.

[Synthesis Example 17] (Synthesis of compound (A-15))
12.5 g of 4-ethenylphenylboronic acid and 7.5 g of vinylbenzyl alcohol are dissolved in 40.0 g of methyl isobutyl ketone, 1.6 g of dimethyl 2,2'-azobis(2-methylpropionate) are added, A polymer solution was prepared. Under a nitrogen atmosphere, 40.0 g of methyl isobutyl ketone was placed in a reaction vessel, heated to 80°C, and while stirring, the above monomer solution was added dropwise over 3 hours, stirred for 6 hours, and cooled to 30°C or less. . 300 g of propylene glycol monomethyl ether acetate was added to the reaction solution, and methyl isobutyl ketone was removed by concentration under reduced pressure, followed by drying to obtain compound (A-15) represented by the following formula (A-15). Mw of the obtained compound (A-15) was 4,200.

[Synthesis Example 18] (Synthesis of polymer (x-4))
3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde 10.2 g is benzaldehyde 4.7 g, p-toluenesulfonic acid monohydrate 4.4 g -Toluenesulfonic acid monohydrate 3.5 g, except that 1-butanol 36.4 g was changed to 1-butanol 25.3 g, in the same manner as in the precursor synthesis of Synthesis Example 10 Polymer (x-4) got Mw of the obtained polymer (x-4) was 4,900.

[Synthesis Example 19] (Synthesis of polymer (x-5))
8.0 g of 1-hydroxypyrene, 16.1 g of 9,9-bis(4-hydroxyphenyl)fluorene, 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) The following polymer (x-5) was obtained in the same manner as the precursor synthesis of Synthesis Example 10 except that 10.2 g of benzaldehyde was changed to 5.8 g of benzaldehyde and 36.4 g of 1-butanol was changed to 43.8 g of 1-butanol. Ta. Mw of the obtained polymer (x-5) was 4,400.

[Comparative Synthesis Example 1] (Synthesis of polymer (x-1))
In a reaction vessel under a nitrogen atmosphere, 250.0 g of m-cresol, 125.0 g of 37 mass% formalin and 2 g of anhydrous oxalic acid were added, reacted at 100 ° C. for 3 hours and at 180 ° C. for 1 hour, and then under reduced pressure. The reaction monomer was removed to obtain the following polymer (x-1). Mw of the obtained polymer (x-1) was 11,000.

[Comparative Synthesis Example 2] (Synthesis of polymer (x-2))
A reaction vessel was charged with 100.0 g of 9,9-bis(4-hydroxyphenyl)fluorene, 300.0 g of propylene glycol monomethyl ether acetate, and 10.0 g of paraformaldehyde under a nitrogen atmosphere. 0 g, stirred at 100 ° C. for 16 hours, the polymerization reaction solution was put into 500.0 g of methanol / water (70/30 (mass ratio)) mixed solvent, and the precipitate was collected with filter paper and dried. By doing so, the following polymer (x-2) was obtained. Mw of the obtained polymer (x-2) was 5,200.

[Comparative Synthesis Example 3] (Synthesis of polymer (x-3))
The following polymer (x-3) was obtained in the same manner as in Synthesis Example 12, except that 10.0 g of 3-hydroxyphenylboronic acid was changed to 6.8 g of phenol. Mw of the obtained polymer (x-3) was 3,500.

<Preparation of composition>
The [A] compound, [B] solvent, [C] acid generator, [D] cross-linking agent and polymer used in the preparation of the composition are shown below.

[[A] compound]
Compounds (A-1) to (A-15) synthesized above

[[B] solvent]
B-1: propylene glycol monomethyl ether acetate B-2: cyclohexanone

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

[[D] cross-linking agent]
D-1: a compound represented by the following formula (D-1)

D-2: a compound represented by the following formula (D-2)

[Polymer]
Polymers (x-1) to (x-5) synthesized above

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

[Examples 2 to 22 and Comparative Examples 1 to 3]
Compositions (J-2) to (J-22) and (CJ-1) to (CJ-3) in the same manner as in Example 1 except that the types and contents of each component shown in Table 1 below were used. ) was prepared. "-" in the columns of "[A] compound", "polymer", "[C] acid generator" and "[D] cross-linking agent" in Table 1 indicates that the corresponding component was not used. show.

[Etching resistance]
The composition prepared above was coated on a silicon wafer (substrate) by a spin coating method using a spin coater ("CLEAN TRACK ACT 12" available from Tokyo Electron Ltd.). Next, after heating at 350° C. for 60 seconds in an air atmosphere, by cooling at 23° C. for 60 seconds, a film having an average thickness of 200 nm was formed, and a film-coated substrate having a resist underlayer film formed on the substrate was obtained. Obtained. The film on the obtained film-coated substrate was etched using an etching device ("TACTRAS" available from Tokyo Electron Co., Ltd.) with O ₂ =400 sccm, PRESS. = 25 mT, HF RF (radio frequency power for plasma generation) = 400 W, LF RF (radio frequency power for bias) = 0 W, DCS = 0 V, RDC (gas center flow ratio) = 50%, 90 seconds. The etching rate (nm/min) was calculated from the average thickness of the films before and after. Next, the ratio to Comparative Example 1 was calculated based on the etching rate of Comparative Example 1, and this ratio was used as a measure of etching resistance. The etching resistance is "A" (extremely good) when the above ratio is 0.89 or less, "B" (good) when it is more than 0.89 and less than 0.93, and "B" when it is 0.93 or more. C” (defective). In addition, "-" in Table 2 indicates that it is an evaluation criterion for etching resistance.

[Heat-resistant]
The composition prepared above was coated on a silicon wafer (substrate) by a spin coating method using a spin coater ("CLEAN TRACK ACT 12" available from Tokyo Electron Ltd.). Next, after heating at 200° C. for 60 seconds in an air atmosphere, by cooling at 23° C. for 60 seconds, a film having an average thickness of 200 nm was formed to obtain a film-coated substrate having a film formed on the substrate. . The powder was collected by scraping the film of the film-coated substrate obtained above, and the collected powder was placed in a container used for measurement with a TG-DTA device (“TG-DTA2000SR” by NETZSCH) and placed in a container before heating. Mass was measured. Next, using the above TG-DTA apparatus, the powder was heated to 400° C. at a heating rate of 10° C./min in a nitrogen atmosphere, and the mass of the powder at 400° C. was measured. Then, the mass reduction rate (%) was measured by the following formula, and this mass reduction rate was used as a measure of heat resistance.
M _L = {(m1−m2)/m1}×100
Here, in the above formula, _ML is the mass reduction rate (%), m1 is the mass before heating (mg), and m2 is the mass at 400°C (mg).
As for the heat resistance, the smaller the mass reduction rate of the sample powder, the less the sublimate and the decomposition product of the film generated during the heating of the film, and the better the heat resistance. That is, the smaller the mass reduction rate, the higher the heat resistance. The heat resistance is "A" (very good) when the mass reduction rate is less than 5%, "B" (good) when it is 5% or more and less than 10%, and "C" when it is 10% or more ( bad).

As can be seen from the results in Table 2, the resist underlayer films formed from the compositions of Examples were excellent in etching resistance and heat resistance.

According to the method for manufacturing a semiconductor substrate of the present invention, a well-patterned substrate can be obtained. The composition of the present invention can form a resist underlayer film having excellent etching resistance and heat resistance. Therefore, these can be suitably used for the manufacture of semiconductor devices, etc., which are expected to be further miniaturized in the future.

Claims (10)

1. a step of directly or indirectly applying a composition for forming a resist underlayer film onto a substrate;
   a step of directly or indirectly forming a resist pattern on the resist underlayer film formed by the coating step;
   and a step of performing etching using the resist pattern as a mask,
   The composition for forming a resist underlayer film is
   a compound having a boron atom;
   A method for manufacturing a semiconductor substrate, comprising a solvent and
2. The method for manufacturing a semiconductor substrate according to claim 1, wherein the compound has an aromatic ring.
3. The method for manufacturing a semiconductor substrate according to claim 1, wherein the content of boron atoms in the compound is 0.1 atm% or more.
4. Before forming the resist pattern,
   4. The method for manufacturing a semiconductor substrate according to claim 1, further comprising the step of forming a silicon-containing film directly or indirectly on said resist underlayer film.
5. a compound having a boron atom;
   A composition for forming a resist underlayer film containing a solvent and
6. The composition for forming a resist underlayer film according to claim 5, wherein the compound has an aromatic ring.
7. The composition for forming a resist underlayer film according to claim 5, wherein the content of boron atoms in the compound is 0.1 atm% or more.
8. 8. The composition for forming a resist underlayer film according to any one of claims 5 to 7, wherein the compound has a partial structure represented by the following formula (i).
   

   

   (In the above formula (i), X ¹ and X ² are each independently a carbon atom, a nitrogen atom or an oxygen atom. Each atom other than a boron atom in the above formula (i) is the above moiety in the above compound It is connected to parts other than the structure.)
9. 9. The composition for forming a resist underlayer film according to claim 8, wherein the compound has a partial structure represented by the following formula (i-1).
   

   

   (In the above formula (i-1),
   Y ¹ and Y ² are each independently -O- or -NR'-. R' is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. When there are multiple R's, the multiple R's are the same or different.
   R ¹ and R ² are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ¹ and R ² are combined with Y ¹ and Y ² to which they are bonded It represents a ring structure with 5 to 20 ring members formed together with a boron atom.
   The carbon atom in formula (i-1) above is bonded to a portion other than the above partial structure in the above compound. )
10. 9. The composition for forming a resist underlayer film according to claim 8, wherein the compound has a partial structure represented by the following formula (i-2).
    

    

    (In the above formula (i-2),
    X ¹ and X ² are synonymous with the above formula (i).
    ^L2 is a single bond or a divalent linking group.
    R ³ is a monovalent organic group having 1 to 20 carbon atoms.
    * represents a binding site with a portion other than the above partial structure in the above compound.
    m is an integer from 0 to 4; When m is 2 or more, multiple R ³ are the same or different.
    n is an integer of 0-2. )