JP6641879B2 - Composition for forming resist underlayer film, method for producing resist underlayer film and patterned substrate - Google Patents

Description

  The present invention relates to a composition for forming a resist underlayer film, a resist underlayer film, and a method for producing a patterned substrate.

  In the manufacture of semiconductor devices, a multilayer resist process is used to obtain a high degree of integration. In this process, first, a composition for forming a resist underlayer film is applied to one surface side of a substrate to form a resist underlayer film, and a resist composition is applied to a surface of the resist underlayer film opposite to the substrate. A resist film is formed. Then, the resist film is exposed through a mask pattern or the like, and is developed with an appropriate developer to form a resist pattern. Then, the resist underlayer film is dry-etched using the resist pattern as a mask, and the substrate is further etched using the obtained resist underlayer film pattern as a mask, thereby forming a desired pattern on the substrate and obtaining a patterned substrate. Can be. The resist underlayer film used in such a multilayer resist process is required to have general characteristics such as optical characteristics such as a refractive index and an absorption coefficient, solvent resistance, and etching resistance.

  In recent years, pattern miniaturization has been further advanced in order to further increase the degree of integration, and even in the above-described multilayer resist process, the resist underlayer film and the composition for forming the same have excellent various characteristics as follows. Is required. In response to this requirement, various studies have been made on the structure of the compound and the like contained in the composition and the functional groups contained therein (see JP-A-2004-177668).

  In the above-described conventional composition for forming a resist underlayer film, the compound contained therein generally has low solubility in a solvent such as propylene glycol monomethyl ether acetate (PGMEA) due to its structure and the like. Therefore, there is a disadvantage that the coatability to the substrate is poor, and as a result, it is difficult to form a uniform resist underlayer film.

  Recently, in the above-described multilayer resist process, a method of forming a hard mask as an intermediate layer on a resist underlayer film has been studied. Specifically, in this method, an inorganic hard mask is formed on the resist underlayer film by a CVD method. In particular, in the case of a nitride-based inorganic hard mask, the temperature is at least 300 ° C., usually 400 ° C. or higher. The lower layer film requires high heat resistance. However, the resist underlayer film formed from the above conventional composition for forming a resist underlayer film has insufficient heat resistance, the components of the resist underlayer film sublimate, and the sublimated components are re-adhered to the substrate, and the semiconductor device There is a disadvantage that the production yield is reduced.

  Further, recently, patterns have been increasingly formed on a substrate having a plurality of types of trenches, particularly trenches having different aspect ratios from each other, and the formed resist underlayer film has been sufficiently filled with these trenches. Is required. However, in the above-described conventional composition for forming a resist underlayer film, such a filling property is insufficient, and the formed resist underlayer film and the hard mask have voids and are not uniform. Therefore, as a result, there is a disadvantage that the lithography characteristics of the obtained resist pattern are reduced.

JP 2004-177668 A

  The present invention has been made based on the above circumstances, and an object of the present invention is to form a resist underlayer film having excellent solvent resistance, etching resistance, heat resistance, and embedding property by using PGMEA or the like as a solvent. An object of the present invention is to provide a composition for forming a resist underlayer film, a resist underlayer film, and a method for producing a patterned substrate.

  The invention made to solve the above problem has a group containing a carbon-carbon triple bond (hereinafter, also referred to as “specific group (A)”) and an aromatic ring (hereinafter, “aromatic ring (A)”). (Hereinafter also referred to as "partial structure (A)"), and the total number of benzene nuclei constituting the aromatic ring (A) in the partial structure (A) is 4 or more. It is a composition for forming a resist underlayer film containing a certain compound (hereinafter, also referred to as “[A] compound”) and a solvent (hereinafter, also referred to as “[B] solvent”).

  Another invention made to solve the above problem is a resist underlayer film formed from the composition for forming a resist underlayer film.

  Yet another invention made in order to solve the above problem, a step of forming a resist underlayer film on one surface side of the substrate, a step of forming a resist pattern on the surface of the resist underlayer film opposite to the substrate, And a step of forming a pattern on the substrate by performing etching a plurality of times using the resist pattern as a mask, wherein the resist underlayer film is formed by the resist underlayer film forming composition.

  Here, the “partial structure” refers to a structure derived from a precursor compound (excluding a compound that provides a linking group described later) used in the synthesis of the compound [A]. "Benzene nucleus" refers to a 6-membered carbon ring having aromaticity. Each 6-membered ring constituting the condensed ring is also called a benzene nucleus. For example, the number of benzene nuclei in a naphthalene ring is 2.

  According to the composition for forming a resist underlayer film of the present invention, PGMEA or the like can be used as a solvent, and a resist underlayer film having excellent solvent resistance, etching resistance, heat resistance, and embedding property can be formed. The resist underlayer film of the present invention is excellent in solvent resistance, etching resistance, heat resistance and burying property. According to the method for manufacturing a patterned substrate of the present invention, a patterned substrate having an excellent pattern shape can be obtained by using the formed excellent resist underlayer film. Therefore, they can be suitably used for the manufacture of semiconductor devices, which are expected to be further miniaturized in the future.

<Composition for forming resist underlayer film>
The resist underlayer film forming composition contains the compound [A] and the solvent [B]. The composition for forming a resist underlayer film may contain [C] an acid generator as a suitable component, and may contain other optional components as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] compound>
[A] The compound is a compound having the specific group (A) and the partial structure (A). When the compound [A] has the specific group (A) and the partial structure (A), the composition for forming a resist underlayer film can use PGMEA or the like as a solvent, and has solvent resistance and etching resistance. And a resist underlayer film having excellent heat resistance and burying property can be formed. [A] The reason that the composition for forming a resist underlayer film exhibits the above-mentioned effects when the compound has the above-mentioned structure is not necessarily clear, but can be guessed as follows, for example. That is, the compound [A] has a specific group (A) containing a carbon-carbon triple bond, has a partial structure (A) containing an aromatic ring (A), and has a benzene nucleus in the partial structure (A). The solubility in a solvent such as PGMEA is increased by making the total number of the compounds equal to or more than a certain value. The composition for forming a resist underlayer film can use such a solvent, and the partial structure (A) of the compound (A) has a certain number or more of benzene nuclei, thereby improving the filling property of the resist underlayer film. Can be done. In addition, it is considered that when the compound [A] has the specific group (A), a higher-order crosslinked structure can be formed when the resist underlayer film is formed. As a result, the resist underlayer film has excellent solvent resistance and etching resistance. In addition, since the partial structure (A) of the compound (A) has a certain number or more of benzene nuclei, the heat resistance of the resist underlayer film is also excellent. It will be.

  [A] The compound may have a partial structure other than the partial structure (A) in addition to the partial structure (A). When the compound [A] has a plurality of the above partial structures, the plurality of partial structures may be bonded via a linking group (hereinafter, also referred to as “linking group (a)”). Hereinafter, the specific group (A), the partial structure (A), other partial structures, and the linking group (a) will be described.

[Specific group (A)]
The specific group (A) is a group containing a carbon-carbon triple bond. The specific group (A) may be present in the compound [A], and the bonding position is not particularly limited. Further, the specific group (A) may be a monovalent group or a divalent or higher group. The specific group (A) may be present, for example, in the partial structure (A) described later or in the linking group. However, from the viewpoint of further improving the heat resistance and the embedding property of the resist underlayer film, It is preferably in A), more preferably in the partial structure (I) and the partial structure (II) described below, and still more preferably in the partial structure (I).

Examples of the specific group (A) include alkynyl groups such as an ethynyl group, a propyn-1-yl group, a propargyl group, a butyn-1-yl group, a butyn-3-yl group, and a butyn-4-yl group;
Examples include an aromatic ring such as a phenylethynyl group and a phenylpropargyl group, and a group having a triple bond. The specific group (A) is preferably an alkynyl group, and more preferably a propargyl group, from the viewpoint of increasing the ease of crosslinking of the compound [A].

  The lower limit of the number of the specific group (A) to be contained is preferably 0.1 mol, more preferably 0.5 mol, and further preferably 0.8 mol, per 1 mol of all partial structures constituting the compound [A]. Preferably, 1.1 mol is particularly preferred. The upper limit of the number is preferably 5 mol, more preferably 4 mol, still more preferably 3 mol, and particularly preferably 2.5 mol. By setting the content number of the specific group (A) in the above range, the crosslinking property of the compound [A] at the time of forming the resist underlayer film can be adjusted to a more appropriate level, and as a result, the solvent of the resist underlayer film can be adjusted. Resistance, etching resistance, heat resistance and burying property can be further improved. [A] The compound may have one or more specific groups (A).

[Partial structure (A)]
The partial structure (A) contains an aromatic ring (A). The total number of benzene nuclei constituting the aromatic ring (A) in the partial structure (A) is 4 or more.

(Aromatic ring (A))
The aromatic ring (A) is a carbon ring having aromaticity. Examples of the aromatic ring (A) include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a tetracene ring, a perylene ring, and a pentacene ring.

  The lower limit of the number of carbon atoms of the aromatic ring (A) is usually 6, preferably 8, and more preferably 10. The upper limit of the number of carbon atoms is preferably 30, more preferably 24, and even more preferably 18.

  The lower limit of the number of aromatic rings (A) contained in the partial structure (A) is usually 1, preferably 2, more preferably 3, and even more preferably 4. As the upper limit of the above number, 8 is preferable, and 6 is more preferable.

  The lower limit of the total number of carbon atoms of the aromatic ring (A) in the partial structure (A) is usually 16, preferably 20 and more preferably 24. As a maximum of the above-mentioned total number, 50 is preferred, 40 is more preferred, and 32 is still more preferred.

  The lower limit of the total number of the benzene nuclei constituting the aromatic ring (A) in the partial structure (A) is 4, preferably 5 and more preferably 6. The upper limit of the total number is preferably 12, more preferably 10, and still more preferably 8. When the total number of benzene nuclei is in the above range, solvent resistance, etching resistance and heat resistance of the resist underlayer film can be further increased. [A] The compound may have one or more aromatic rings (A).

  A group other than a hydrogen atom such as a specific group (A), a group containing a carbon-carbon double bond, an alkyl group, a hydroxy group, or an alkoxy group is bonded to a carbon atom constituting the ring of the aromatic ring (A). May be.

  As the partial structure (A), for example, a first partial structure represented by the following formula (1) (hereinafter also referred to as “partial structure (I)”), a second partial structure represented by the following formula (2) ( Hereinafter, also referred to as “partial structure (II)”).

In the above formula (1), R ^{1 to} R ⁴ are each independently a hydrogen atom, a monovalent group containing a carbon-carbon triple bond or a monovalent group containing a carbon-carbon double bond. m1 and m2 are each independently an integer of 0 to 2. a1 and a2 are each independently an integer of 0 to 9. n1 and n2 are each independently an integer of 0 to 2. a3 and a4 are each independently an integer of 0 to 8; When each of R ^{1 to} R ⁴ is plural, plural R ¹ may be the same or different, plural R ² may be the same or different, plural R ³ may be the same or different, A plurality of R ⁴ may be the same or different. p1 and p2 are each independently an integer of 0 to 9. p3 and p4 are each independently an integer of 0 to 8; p1 + p2 + p3 + p4 is 0 or more. a1 + p1 and a2 + p2 are each 9 or less. a3 + p3 and a4 + p4 are each 8 or less. * Indicates a binding site to a portion other than the partial structure (I) in the compound [A].

In the formula (2), R ^{5 to} R ⁸ each independently represent an alkyl group, a hydroxy group, an alkoxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. It is a group of. b1 and b3 are each independently an integer of 0 to 2. b2 and b4 are each independently an integer of 0 to 3. When each of R ^{5 to} R ⁸ is plural, plural R ⁵ may be the same or different, plural R ⁶ may be the same or different, plural R ⁷ may be the same or different, A plurality of R ⁸ may be the same or different. q1 and q3 are each independently an integer of 0 to 2. q2 and q4 are each independently an integer of 0 to 3. q1 + q2 + q3 + q4 is 0 or more. b1 + q1 and b3 + q3 are each 2 or less. b2 + q2 and b4 + q4 are each 3 or less. * Indicates a binding site to a part other than the partial structure (II) in the compound [A].

Examples of the monovalent group containing a carbon-carbon triple bond represented by R ^{1 to} R ⁴ in the formula (1) include monovalent groups among the groups exemplified as the specific group (A). Among these, an alkynyl group is preferred, and a propargyl group is more preferred.

Examples of the monovalent group containing a carbon-carbon double bond represented by R ^{1 to} R ⁴ include an ethenyl group, a propen-1-yl group, a propen-2-yl group, a propen-3-yl group, a butene Alkenyl groups such as -1-yl, buten-2-yl, buten-3-yl and buten-4-yl;
Examples include a group containing an aromatic ring and a double bond such as a phenylethenyl group and a phenylpropenyl group.

Preferably, at least one of R ^{1 to} R ⁴ is a group containing a carbon-carbon triple bond, and more preferably, R ¹ and R ² are groups containing a carbon-carbon triple bond. As described above, by including the specific group (A) in the partial structure (I), the crosslinkability of the compound [A] is further improved, and as a result, the solvent resistance, etching resistance, heat resistance, and burying of the resist underlayer film are improved. Properties can be further improved.

  As m1 and m2, 0 and 1 are preferable. a1 and a2 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 1. a3 and a4 are preferably integers of 0 to 2, more preferably 0 and 1, and even more preferably 0. p1 and p2 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 1. p3 and p4 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 0. The lower limit of p1 + p2 + p3 + p4 is preferably 1. As an upper limit of p1 + p2 + p3 + p4, 34 is preferable, 18 is more preferable, 8 is further preferable, 4 is particularly preferable, 3 is particularly preferable, and 2 is most preferable.

Examples of the alkyl group represented by R ^{5 to} R ⁸ in the above formula (2) include an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Group, octyl group, decyl group and the like.

Examples of the alkoxy group represented by R ^{5 to} R ⁸ include an alkoxy group having 1 to 20 carbon atoms and the like, and include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and an octyloxy group. And a decyloxy group.

Examples of the monovalent group containing a carbon-carbon triple bond represented by R ^{5 to} R ⁸ include a monovalent group among those exemplified as the specific group (A), and an oxygen atom at the terminal of the bond side of this group. Examples include groups having atoms.

The group containing a carbon-carbon double bond represented by R ^{5 to} R ⁸ is, for example, the same as the group exemplified as the group containing a carbon-carbon double bond of R ^{1 to} R ^{4 in} the above formula (1). And a group having an oxygen atom at the terminal on the bond side of the group.

  As b1 and b3, 0 and 1 are preferable, and 0 is more preferable. As b2 and b4, an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is further preferable. As q1 and q3, 0 and 1 are preferable, and 1 is more preferable. q2 and q4 are preferably integers of 0 to 2, more preferably 0 and 1, and even more preferably 0. The lower limit of q1 + q2 + q3 + q4 is preferably 1. As an upper limit of q1 + q2 + q3 + q4, 10 is preferable, 8 is more preferable, 6 is further preferable, 4 is particularly preferable, 3 is further preferable, and 2 is most preferable.

As R ^{5 to} R ⁸ , a monovalent group containing an alkyl group, a hydroxy group and a carbon-carbon triple bond is preferable, a monovalent group containing a hydroxy group and a carbon-carbon triple bond is more preferable, and a hydroxy group and an alkynyl are preferable. Oxy groups are more preferred, hydroxy and propargyloxy groups are particularly preferred.

  Examples of the partial structure (I) include partial structures represented by the following formulas (1-1) to (1-6) (hereinafter, also referred to as “partial structures (I-1) to (I-6)”) and the like. Is mentioned. As the partial structure (II), for example, partial structures represented by the following formulas (2-1) to (2-6) (hereinafter, also referred to as “partial structures (II-1) to (II-6)”) and the like Is mentioned.

In the above formulas (1-1) to (1-6), ^RA is a monovalent specific group (A). R ^B is a carbon - is a monovalent group containing a carbon double bond. p1 to p4 have the same meaning as in the above formula (1). * Indicates a binding site to a portion other than the partial structures (I-1) to (I-6) in the compound [A].

In the above formulas (2-1) to (2-6), ^RA is a monovalent specific group (A). R ^B is a carbon - is a monovalent group containing a carbon double bond. q1 to q4 have the same meanings as in the above formula (2). * Indicates a binding site to a portion other than the partial structures (II-1) to (II-6) in the compound [A].

  As the partial structure (I), the partial structures (I-1), (I-2) and (I-4) are preferable, and the partial structures (I-1) and (I-2) are more preferable. As the partial structure (II), the partial structures (II-1) and (II-2) are preferable, and the partial structure (II-1) is more preferable.

  [A] The compound preferably has at least one of the partial structure (I) and the partial structure (II) as the partial structure (A), more preferably has the partial structure (I), and has a partial structure ( More preferably, it has I) and partial structure (II). The compound [A], having the above partial structure, has higher solubility in a solvent, and as a result, the filling property of the resist underlayer film is further improved.

  When the compound [A] has the partial structure (I), the lower limit of the content ratio of the partial structure (I) is preferably 10 mol% based on the total partial structure (A) constituting the compound [A]. 30 mol% is more preferable, and 50 mol% is still more preferable. The upper limit of the content ratio is preferably 100 mol%, more preferably 95 mol%, and still more preferably 75 mol%. By setting the content ratio of the partial structure (I) in the above range, the solubility of the compound [A] in the solvent can be further increased, and as a result, the heat resistance and the burying property of the resist underlayer film can be increased at a higher level. Can be compatible.

  When the compound [A] has the partial structure (II), the lower limit of the content ratio of the partial structure (II) is preferably 10 mol% based on all partial structures (A) constituting the compound [A]. 20 mol% is more preferable, and 30 mol% is still more preferable. As a maximum of the above-mentioned content rate, 100 mol% is preferred, 80 mol% is more preferred, and 50 mol% is still more preferred. By setting the content of the partial structure (II) in the above range, the content of the polycyclic structure in the compound [A] can be increased, and as a result, the heat resistance and the burying property of the resist underlayer film can be increased to a higher level. Can be compatible. [A] The compound may have one or more partial structures (A).

[Other partial structures]
[A] Examples of the partial structure other than the partial structure (A) in the compound include partial structures represented by the following formulas (3) to (6), partial structures not containing an aromatic ring, and the like.

In the above formula (3), R ⁹ is an alkyl group, a hydroxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. c1 is an integer of 0 to 5. When c1 is 2 or more, a plurality of R ⁹ may be the same or different. r1 is an integer of 1 to 6. c1 + r1 is 6 or less.
In the above formula (4), R ¹⁰ is an alkyl group, a hydroxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. c2 is an integer of 0 to 7. When c2 is 2 or more, a plurality of R ¹⁰ may be the same or different. r2 is an integer of 1 to 8. c2 + r2 is 8 or less.
In the above formula (5), R ¹¹ is an alkyl group, a hydroxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. c3 is an integer of 0-9. When c3 is 2 or more, a plurality of R ¹¹ may be the same or different. r3 is an integer of 1 to 10. c3 + r3 is 10 or less.
In the above formula (6), R ¹² is an alkyl group, a hydroxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. c4 is an integer of 0-9. When c4 is 2 or more, a plurality of R ¹² may be the same or different. r4 is an integer of 1 to 10. c4 + r4 is 10 or less.

As R ^{9 in the} above formula (3), a monovalent group containing a carbon-carbon triple bond and a hydroxy group are preferred, a monovalent group containing a carbon-carbon triple bond is more preferred, and an alkynyloxy group is still more preferred. Propargyloxy groups are particularly preferred. c1 is preferably 1. r1 is preferably 1 to 3, and more preferably 2.

As R ^{10 in the} above formula (4), a monovalent group containing a carbon-carbon triple bond and a hydroxy group are preferred, a monovalent group containing a carbon-carbon triple bond is more preferred, and an alkynyloxy group is still more preferred. Propargyloxy groups are particularly preferred. c2 is preferably 1. r2 is preferably 1 to 3, and more preferably 2.

As R ^{11 in the} above formula (5), a monovalent group containing a carbon-carbon triple bond and a hydroxy group are preferred, a monovalent group containing a carbon-carbon triple bond is more preferred, and an alkynyloxy group is still more preferred. Propargyloxy groups are particularly preferred. As c3, 0 and 1 are preferable, and 0 is more preferable. r3 is preferably 1 to 3, and more preferably 2.

As R ^{12 in the} above formula (6), a monovalent group containing a carbon-carbon triple bond and a hydroxy group are preferred, a monovalent group containing a carbon-carbon triple bond is more preferred, and an alkynyloxy group is still more preferred. Propargyloxy groups are particularly preferred. As c4, 0 and 1 are preferable, and 0 is more preferable. r4 is preferably 1 to 3, and more preferably 2.

  Examples of the partial structure not containing an aromatic ring include a partial structure composed of a substituted or unsubstituted chain hydrocarbon group and a partial structure composed of a substituted or unsubstituted alicyclic hydrocarbon group.

  The lower limit of the content ratio of the partial structure (A) is preferably 40 mol%, more preferably 50 mol%, still more preferably 60 mol%, and more preferably 70 mol%, based on all partial structures constituting the compound [A]. Is particularly preferred. The upper limit of the content ratio is preferably 100 mol%, more preferably 95 mol%, and still more preferably 90 mol%. By setting the content ratio of the partial structure (A) within the above range, the heat resistance and the burying property of the resist underlayer film can be further improved.

  When the compound [A] has another partial structure, the lower limit of the content ratio of the other partial structure is preferably 1 mol%, more preferably 5 mol%, based on all the partial structures constituting the compound [A]. Preferably, 10 mol% is more preferable. As a maximum of the above-mentioned content rate, 60 mol% is preferred, 50 mol% is more preferred, 40 mol% is still more preferred, and 30 mol% is especially preferred. By setting the content of the other partial structure in the above range, the solvent resistance, etching resistance, heat resistance, and burying property of the resist underlayer film can be further improved.

[Linking group]
[A] When the compound has a plurality of partial structures, these partial structures may be bonded via the linking group (a). When the compound [A] has a plurality of partial structures (A), the plurality of partial structures (A) may be bonded via a linking group (a).

Examples of the linking group (a) include a linking group derived from an aldehyde. When the linking group derived from an aldehyde is derived from a compound containing one aldehyde group, it usually has a structure of -CHR- (R is a monovalent hydrocarbon group). As R, a hydrogen atom and an aryl group are preferable, a hydrogen atom and a pyrenyl group are more preferable, and a hydrogen atom is further preferable. Linking groups derived from formaldehyde, typically -CH ₂ - is.

As an aldehyde,
Examples of the compound containing one aldehyde group include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, naphthaldehyde, and formylpyrene.
Examples of the compound containing two or more aldehyde groups include 1,4-phenylenedialdehyde and 4,4′-biphenylenedialdehyde.

  When the compound [A] has a linking group (a), the lower limit of the content ratio of the linking group (a) to 1 mole of all partial structures constituting the compound [A] is preferably 0.1 mol, and 0.3 mol. Mole is more preferred, and 0.5 mole is even more preferred. The upper limit of the content ratio is preferably 3 mol, more preferably 2 mol, and still more preferably 1.5 mol. By setting the content of the linking group (a) in the above range, the crosslinking density of the compound [A] by the linking group (a) can be more appropriately adjusted, and as a result, the solvent resistance of the resist underlayer film and the etching can be improved. Resistance, heat resistance and embeddability can be further improved.

  Examples of the compound [A] include compounds having structures represented by the following formulas (A-1) to (A-11) (hereinafter, also referred to as “compounds (A1) to (A11)”).

In the above formulas (A-1) to (A-11), ^RA is a monovalent specific group (A).

  Among these, as the [A] compound, compounds (A1) to (A5) and (A7) to (A11) are preferable, and compounds (A1), (A3) to (A5) and (A7) to (A11) are preferable. Is more preferable, and the compounds (A1) and (A7) to (A11) are still more preferable.

  The lower limit of the content of the compound (A) is preferably 70% by mass, more preferably 80% by mass, and 85% by mass based on the total solids (components other than the solvent) in the composition for forming a resist underlayer film. % Is more preferred.

<Synthesis method of [A] compound>
[A] The compound can be synthesized by a known method. [A] When the compound is a polymer obtained by crosslinking a compound giving the partial structure (A) with an aldehyde, first, for example, a phenolic hydroxyl group-containing compound represented by the following formula (1-m); ) Is reacted with an aldehyde in the presence of an acid in a solvent such as propylene glycol monomethyl ether acetate to obtain a polymer having a phenolic hydroxyl group. Next, the obtained polymer is reacted with a compound that forms a specific group (A) such as propargyl bromide in a solvent such as N, N-dimethylacetamide in the presence of a base to obtain [A]. Compounds can be synthesized. One or more of the above-mentioned precursor compounds can be used, and the use ratio thereof can be appropriately selected depending on the desired performance of the resist underlayer film and the like. Further, the usage ratio of the precursor compound and the aldehyde can be appropriately selected depending on the desired performance of the resist underlayer film and the like.

In the above formula (1-m), m1, m2, n1, n2 and a1 to a4 have the same meanings as in the above formula (1).
In the formula (2-m), R ^{5 to} R ⁸ and b1 to b4 have the same meanings as in the formula (2).

  Examples of the aldehyde include compounds containing one aldehyde group such as formaldehyde (paraformaldehyde), acetaldehyde (paraaldehyde), propionaldehyde, butyraldehyde, benzaldehyde, naphthaldehyde, and formylpyrene; 1,4-phenylenedialdehyde, Compounds containing two or more aldehyde groups such as 4'-biphenylenedialdehyde are exemplified. Among these, the compound having one aldehyde group is preferred from the viewpoint that the compound [A] has a more appropriate cross-linked structure, so that the solvent resistance, etching resistance, heat resistance, and filling property of the resist underlayer film are further improved. Preferably, formaldehyde and formylpyrene are more preferred, and formaldehyde is even more preferred.

  Examples of the acid include sulfonic acids such as p-toluenesulfonic acid and benzenesulfonic acid; and inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid. Of these, sulfonic acid is preferred, and p-toluenesulfonic acid is more preferred.

  The lower limit of the amount of the acid used is preferably 1 mol, more preferably 5 mol, per 1 mol of the aldehyde. The upper limit of the amount used is preferably 20 mol, more preferably 10 mol.

  The lower limit of the reaction temperature for the synthesis reaction of the polymer having a phenolic hydroxyl group is preferably 60 ° C, more preferably 80 ° C. The upper limit of the reaction temperature is preferably 150 ° C, more preferably 120 ° C. The lower limit of the reaction time of the above reaction is preferably 1 hour, more preferably 4 hours. The upper limit of the reaction time is preferably 24 hours, and more preferably 12 hours.

  Examples of the base include alkali metal carbonates such as potassium carbonate and sodium carbonate; alkali metal hydrogen carbonates such as lithium hydrogen carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate; alkali metal hydroxides such as potassium hydroxide and sodium hydroxide An alkali metal hydride such as lithium hydride, sodium hydride and potassium hydride; Of these, alkali metal carbonates are preferred, and potassium carbonate is more preferred.

  The lower limit of the amount of the base used is preferably 0.1 mol, more preferably 0.5 mol, and still more preferably 0.8 mol, per 1 mol of the compound forming the specific group (A). The upper limit of the amount used is preferably 3 mol, more preferably 2 mol, and still more preferably 1.5 mol.

  The lower limit of the reaction temperature of the reaction for obtaining the compound [A] by reacting the compound forming the specific group (A) is preferably 50 ° C, more preferably 60 ° C. The upper limit of the reaction temperature is preferably 130 ° C, more preferably 100 ° C. The lower limit of the reaction time of the above reaction is preferably 1 hour, more preferably 4 hours. The upper limit of the reaction time is preferably 24 hours, and more preferably 12 hours.

  The compound [A] obtained by the synthesis can be purified from the reaction solution by a liquid separation operation, reprecipitation, recrystallization, distillation, or the like. Compounds [A] other than those described above can be synthesized in the same manner as described above.

  [A] The lower limit of the molecular weight of the compound is preferably 250, more preferably 1,000, still more preferably 2,000, and particularly preferably 3,000. The upper limit of the molecular weight is preferably 10,000, more preferably 7,000, still more preferably 6,000, and particularly preferably 5,000.

  When the compound [A] is a polymer, the lower limit of the weight average molecular weight (Mw) of the compound [A] is preferably 1,000, more preferably 2,000, still more preferably 3,000, and 4,000. Is particularly preferred. The upper limit of Mw is preferably 15,000, more preferably 10,000, further preferably 8,500, and particularly preferably 7,000.

  By setting the molecular weight of the compound (A) within the above range, the solvent resistance, etching resistance, heat resistance, and filling property of the resist underlayer film can be further improved.

  When the compound [A] is a polymer, the upper limit of the ratio (Mw / Mn ratio) of Mw of the compound [A] to the number average molecular weight (Mn) is preferably 5, more preferably 3, and still more preferably 2. And 1.8 are particularly preferred. The lower limit of the above ratio is usually 1 and preferably 1.2. By setting the Mw / Mn ratio of the compound [A] in the above range, the filling property of the resist underlayer film can be further improved.

<[B] solvent>
The composition for forming a resist underlayer film contains a solvent [B]. [B] The solvent is not particularly limited as long as it can dissolve or disperse the compound [A] and optional components contained as necessary.

  [B] The solvent includes, for example, alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents and the like. [B] The solvent can be used alone or in combination of two or more.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, t-butanol, n-pentanol, iso-pentanol, and sec-pentanol. Monoalcohol solvents such as, t-pentanol;
Such as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, and 2,4-heptanediol; And polyhydric alcohol solvents.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n Aliphatic ketone solvents such as hexyl ketone, di-iso-butyl ketone and trimethylnonanone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone;
Examples thereof include 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, and methyl n-amyl ketone.

Examples of the amide solvent include cyclic amide solvents such as 1,3-dimethyl-2-imidazolidinone and N-methyl-2-pyrrolidone;
Chain amide solvents such as formamide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide and the like. Can be

Examples of the ether solvent include polyether alcohol partial ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol dimethyl ether;
Polyhydric alcohol partial ether acetate solvents such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), and propylene glycol monoethyl ether acetate;
Dialiphatic ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether, diisoamyl ether;
Aliphatic-aromatic ether solvents such as anisole and phenylethyl ether;
Cyclic ether solvents such as tetrahydrofuran, tetrahydropyran, and dioxane;

Examples of the ester solvent include methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, Sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, methyl acetoacetate, etc. Acid ester solvents;
lactone solvents such as γ-butyrolactone and γ-valerolactone;
Examples thereof include carbonate solvents such as diethyl carbonate and propylene carbonate.

  Among them, ether solvents, ketone solvents and ester solvents are preferred, and ether solvents are more preferred. As the ether solvent, a polyhydric alcohol partial ether acetate solvent and a dialiphatic ether solvent are preferable, a polyhydric alcohol partial ether acetate solvent is more preferable, propylene glycol monoalkyl ether acetate is more preferable, and PGMEA is particularly preferable. . As the ketone solvent, a cyclic ketone solvent is preferable, and cyclohexanone and cyclopentanone are more preferable. As the ester-based solvent, a carboxylate-based solvent and a lactone-based solvent are preferred, a carboxylate-based solvent is more preferred, and ethyl lactate is still more preferred.

  The polyhydric alcohol partial ether acetate solvent, especially propylene glycol monoalkyl ether acetate, particularly PGMEA, is contained in the solvent [B], so that the composition for forming a resist underlayer film can be applied to a substrate such as a silicon wafer. Is preferred because it is possible to improve Since the compound [A] contained in the composition for forming a resist underlayer film has high solubility in PGMEA and the like, by adding a polyhydric alcohol partial ether acetate solvent to the solvent [B], The composition for forming a resist underlayer film can exhibit excellent coating properties, and as a result, the filling property of the resist underlayer film can be further improved. [B] The lower limit of the content of the polyhydric alcohol partial ether acetate solvent in the solvent is preferably 20% by mass, more preferably 60% by mass, still more preferably 90% by mass, and particularly preferably 100% by mass.

<[C] acid generator>
[C] The acid generator is a component that generates an acid by the action of heat or light and promotes the crosslinking of the compound [A]. When the composition for forming a resist underlayer film contains the acid generator [C], the crosslinking reaction of the compound [A] is promoted, and the hardness of the formed film can be further increased. [C] The acid generator can be used alone or in combination of two or more.

  [C] Examples of the acid generator include an onium salt compound and an N-sulfonyloxyimide compound.

  Examples of the onium salt compound include a sulfonium salt, a tetrahydrothiophenium salt, and an iodonium salt.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, and triphenylsulfonium 2-bicyclo [2.2.1] hept-. 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro- n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept- -Yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium par Fluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate and the like can be mentioned.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate and 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Ium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (6-n-butoxynaphthalene-2) Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene- 2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium perfluoro-n-octance Honate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate and the like No.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, and diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-. 1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t -Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Le Oro ethanesulfonate.

  Examples of the N-sulfonyloxyimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and N- (nonafluoro-n-butanesulfonyloxy) ) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept- 5-ene-2,3-dicarboximide and the like.

  Among these, as the [C] acid generator, an onium salt compound is preferable, an iodonium salt is more preferable, and bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is more preferable.

When the composition for forming a resist underlayer film contains [C] an acid generator, the lower limit of the content of the [C] acid generator is 0.1 part by mass with respect to 100 parts by mass of the [A] compound. Is preferred,
1 part by mass is more preferable, and 3 parts by mass is further preferable. The upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and still more preferably 10 parts by mass. By setting the content of the acid generator [C] in the above range, the crosslinking reaction of the compound [A] can be more effectively promoted.

<Other optional ingredients>
The composition for forming a resist underlayer film includes, as other optional components, for example, a crosslinking agent, a surfactant, an adhesion aid, and the like.

[Crosslinking agent]
The crosslinking agent is a component that forms a cross-linking between components such as the compound [A] in the composition for forming a resist underlayer film by the action of heat or an acid. When the composition for forming a resist underlayer film contains a crosslinking agent, the hardness of the formed film can be increased. The crosslinking agent can be used alone or in combination of two or more.

  Examples of the crosslinking agent include a polyfunctional (meth) acrylate compound, an epoxy compound, a hydroxymethyl group-substituted phenol compound, an alkoxyalkyl group-containing phenol compound, a compound having an alkoxyalkylated amino group, and a compound represented by the following formula (7-P). And a random copolymer of acenaphthylene and hydroxymethylacenaphthylene represented by the following formulas (7-1) to (7-12).

  Examples of the polyfunctional (meth) acrylate compound include trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, ethylene glycol di (meth) acrylate, 1,3-butanediol Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) Acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate.

  Examples of the epoxy compound include a novolak epoxy resin, a bisphenol epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxy resin.

  Examples of the hydroxymethyl group-substituted phenol compound include 2-hydroxymethyl-4,6-dimethylphenol, 1,3,5-trihydroxymethylbenzene, 3,5-dihydroxymethyl-4-methoxytoluene [2,6- Bis (hydroxymethyl) -p-cresol].

  Examples of the alkoxyalkyl group-containing phenol compound include a methoxymethyl group-containing phenol compound and an ethoxymethyl group-containing phenol compound.

  Examples of the compound having an alkoxyalkylated amino group include a plurality of compounds in one molecule such as (poly) methylolated melamine, (poly) methylolated glycoluril, (poly) methylolated benzoguanamine, (poly) methylolated urea, and the like. A nitrogen-containing compound having two active methylol groups, wherein at least one of the hydroxyl group hydrogen atoms of the methylol group is substituted by an alkyl group such as a methyl group or a butyl group. The compound having an alkoxyalkylated amino group may be a mixture of a plurality of substituted compounds, or may contain an oligomer component obtained by partially self-condensing.

  In the above formulas (7-6), (7-8), (7-11) and (7-12), Ac represents an acetyl group.

The compounds represented by the above formulas (7-1) to (7-12) can be respectively synthesized with reference to the following documents.
Compound represented by formula (7-1):
Guo, Qun-Sheng; Lu, Young-Na; Liu, Bing; Xiao, Jian; Li, Jin-Shan Journal of Organometallic Chemistry, 2006, vol. 691, # 6 p. 1282-1287
Compound represented by formula (7-2):
Badar, Y .; et al. Journal of the Chemical Society, 1965, p. 1412-1418
Compound represented by formula (7-3):
Hsieh, Jen-Chieh; Cheng, Chien-Hong Chemical Communications (Cambridge, United Kingdom), 2008, # 26 p. 2992-2994
Compound represented by formula (7-4):
JP, 5-238990, A compound denoted by a formula (7-5):
Bacon, R .; G. FIG. R. Bankhead, R .; Journal of the Chemical Society, 1963, p. 839-845
Compounds represented by formulas (7-6), (7-8), (7-11) and (7-12):
Macromolecules 2010, vol 43, p 2832-2839
Compounds represented by formulas (7-7), (7-9) and (7-10):
Polymer Journal 2008, vol. 40, no. 7, p645-650, and Journal of Polymer Science: Part A, Polymer Chemistry, Vol 46, p4949-4968.

  Among these crosslinking agents, a methoxymethyl group-containing phenol compound, a compound having an alkoxyalkylated amino group and a random copolymer of acenaphthylene and hydroxymethylacenaphthylene are preferable, and the alkoxyalkylated amino group is preferably used. Are more preferred, and 1,3,4,6-tetra (methoxymethyl) glycoluril is even more preferred.

  When the composition for forming a resist underlayer film contains a crosslinking agent, the lower limit of the content of the crosslinking agent is preferably 0.1 part by mass, and more preferably 0.5 part by mass with respect to 100 parts by mass of the compound [A]. Is more preferably 1 part by mass, and particularly preferably 3 parts by mass. The upper limit of the content is preferably 100 parts by mass, more preferably 50 parts by mass, still more preferably 30 parts by mass, and particularly preferably 20 parts by mass. By setting the content of the crosslinking agent in the above range, the crosslinking reaction of the compound [A] can be caused more effectively.

[Surfactant]
The composition for forming a resist underlayer film can improve coatability by containing a surfactant, and as a result, coating surface uniformity of a formed film is improved and generation of coating unevenness is suppressed. can do. Surfactants can be used alone or in combination of two or more.

  Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene-n-octylphenyl ether, polyoxyethylene-n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene. Nonionic surfactants such as glycol distearate and the like can be mentioned. Commercial products include KP341 (Shin-Etsu Chemical Co., Ltd.) and Polyflow No. 75; 95 (Kyoeisha Yushi Kagaku Kogyo), F-Top EF101, EF204, EF303, EF352 (Tochem Products), MegaFac F171, F172, F173 (DIC, DIC), Florard FC430 FC431, FC135, FC93 (Sumitomo 3M), Asahi Guard AG710, Surflon S382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass) Can be

  When the composition for forming a resist underlayer film contains a surfactant, the lower limit of the content of the surfactant is preferably 0.01 part by mass with respect to 100 parts by mass of the compound [A], and is preferably 0.05 part by mass. A part by mass is more preferred, and 0.1 part by mass is even more preferred. The upper limit of the content is preferably 10 parts by mass, more preferably 5 parts by mass, and still more preferably 1 part by mass. By setting the content of the surfactant in the above range, the coating property of the composition for forming a resist underlayer film can be further improved.

[Adhesion aid]
The adhesion aid is a component that improves the adhesion to the base. When the composition for forming a resist underlayer film contains an adhesion aid, the adhesion between the formed resist underlayer film and a substrate or the like as a base can be improved. The adhesion aid can be used alone or in combination of two or more.

  As the adhesion aid, for example, a known adhesion aid can be used.

  When the composition for forming a resist underlayer film contains an adhesion aid, the lower limit of the content of the adhesion aid is preferably 0.01 part by mass with respect to 100 parts by mass of the compound [A], and is preferably 0.05 part by mass. A part by mass is more preferred, and 0.1 part by mass is even more preferred. The upper limit of the content is preferably 10 parts by mass, more preferably 10 parts by mass, and still more preferably 5 parts by mass.

<Method of preparing composition for forming resist underlayer film>
The composition for forming a resist underlayer film is obtained by mixing the compound [A], the solvent [B], and if necessary, the acid generator [C] and other optional components at a predetermined ratio, and preferably obtains a mixture. Is filtered through a membrane filter of about 0.1 μm or the like. The lower limit of the solid content concentration of the composition for forming a resist underlayer film is preferably 0.1% by mass, more preferably 1% by mass, still more preferably 2% by mass, and particularly preferably 4% by mass. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, still more preferably 15% by mass, and particularly preferably 8% by mass.

<Method of manufacturing patterned substrate>
The method for producing a patterned substrate of the present invention comprises:
A step of forming a resist underlayer film on one side of the substrate (hereinafter, also referred to as a “resist underlayer film forming step”);
A step of forming a resist pattern on the surface of the resist underlayer film opposite to the substrate (hereinafter, also referred to as a “resist pattern forming step”), and forming a pattern on the substrate by performing etching multiple times using the resist pattern as a mask (Hereinafter, also referred to as a “substrate pattern forming step”). In the method for manufacturing a patterned substrate, the resist underlayer film is formed using the above-described composition for forming a resist underlayer film.

  According to the method for producing a patterned substrate, since the above-described composition for forming a resist underlayer film is used, it is possible to form a resist underlayer film having excellent solvent resistance, etching resistance, heat resistance, and embedding property. By using an excellent resist underlayer film, a patterned substrate having an excellent pattern shape can be obtained.

[Resist underlayer film forming step]
In this step, a resist underlayer film is formed on one surface side of the substrate using the composition for forming a resist underlayer film. The formation of the resist underlayer film is usually performed by applying the composition for forming a resist underlayer film to one surface side of a substrate to form a coating film, and heating the coating film.

  Examples of the substrate include a silicon wafer and a wafer coated with aluminum. The method for applying the composition for forming a resist underlayer film to a substrate or the like is not particularly limited, and for example, can be carried out by an appropriate method such as spin coating, casting coating, or roll coating.

  The heating of the coating film is usually performed in the atmosphere. As a minimum of heating temperature, 150 ° C is preferred, 180 ° C is more preferred, and 200 ° C is still more preferred. As a maximum of heating temperature, 500 ° C is preferred, 380 ° C is more preferred, and 300 ° C is still more preferred. When the heating temperature is lower than 150 ° C., oxidative crosslinking does not proceed sufficiently, and the properties required as a resist underlayer film may not be exhibited. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds, and even more preferably 45 seconds. The upper limit of the heating time is preferably 1,200 seconds, more preferably 600 seconds, and even more preferably 300 seconds.

  The lower limit of the oxygen concentration during heating is preferably 5% by volume. When the oxygen concentration at the time of heating is low, oxidative crosslinking of the resist underlayer film does not sufficiently proceed, and the properties required for the resist underlayer film may not be exhibited.

  Before heating the coating film at a temperature of 150 ° C or more and 500 ° C or less, it may be preheated at a temperature of 60 ° C or more and 250 ° C or less. The lower limit of the heating time in the preheating is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the heating time is preferably 300 seconds, and more preferably 180 seconds. By performing the preheating, the solvent is vaporized in advance and the film is made dense, so that the dehydrogenation reaction can efficiently proceed.

  In the method of forming a resist underlayer film, usually, the coating film is heated to form a resist underlayer film. However, when the composition for forming a resist underlayer film contains a radiation-sensitive acid generator, Alternatively, the resist underlayer film can be formed by curing the coating film by combining exposure and heating. The radiation used for this exposure may be, depending on the type of the radiation-sensitive acid generator, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-rays, and γ-rays; and electron beams, molecular beams, and particle beams such as ion beams. It is appropriately selected.

  The lower limit of the average thickness of the formed resist underlayer film is preferably 0.05 μm, more preferably 0.1 μm, and still more preferably 0.5 μm. The upper limit of the average thickness is preferably 5 μm, more preferably 3 μm, and still more preferably 2 μm.

  After the step of forming a resist underlayer film, a step of forming an intermediate layer (intermediate film) on the surface of the resist underlayer film opposite to the substrate, if necessary, may be further provided. This intermediate layer is a layer provided with the above functions in order to further supplement the functions of the resist underlayer film and / or the resist film in the formation of the resist pattern, or to provide functions which these do not have. . For example, when the antireflection film is formed as an intermediate layer, the antireflection function of the resist underlayer film can be further supplemented.

  This intermediate layer can be formed of an organic compound or an inorganic oxide. Examples of the organic compound include commercially available products such as “DUV-42”, “DUV-44”, “ARC-28”, and “ARC-29” (above, Brewer Science); “AR-3”, “AR -19 "(above, Rohm and Haas Company) and the like. As the inorganic oxide, commercially available products include, for example, “NFC SOG01”, “NFC SOG04”, “NFC SOG080” (above, JSR). Alternatively, polysiloxane, titanium oxide, alumina oxide, tungsten oxide, or the like formed by a CVD method can be used.

  The method for forming the intermediate layer is not particularly limited, and for example, a coating method, a CVD method, or the like can be used. Among these, the coating method is preferred. When the coating method is used, the intermediate layer can be continuously formed after the formation of the resist underlayer film. Further, the average thickness of the intermediate layer is appropriately selected according to the function required of the intermediate layer, but the lower limit of the average thickness of the intermediate layer is preferably 10 nm, more preferably 20 nm. The upper limit of the average thickness is preferably 3,000 nm, more preferably 300 nm.

[Resist pattern formation step]
In this step, a resist pattern is formed on the surface of the resist underlayer film opposite to the substrate. As a method for performing this step, for example, a method using a resist composition and the like can be mentioned.

  In the method using the resist composition, specifically, after applying the resist composition so that the obtained resist film has a predetermined thickness, by pre-baking to evaporate the solvent in the coating film, the resist Form a film.

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

  As a minimum of solid concentration of the above-mentioned resist composition, 0.3 mass% is preferred and 1 mass% is more preferred. The upper limit of the solid content concentration is preferably 50% by mass, and more preferably 30% by mass. The resist composition is generally filtered through a filter having a pore size of about 0.2 μm, for example, and used for forming a resist film. In this step, a commercially available resist composition can be used as it is.

  The method for applying the resist composition is not particularly limited, and examples thereof include a spin coating method. The prebaking temperature is appropriately adjusted according to the type of the resist composition used, etc., but the lower limit of the temperature is preferably 30 ° C, more preferably 50 ° C. The upper limit of the temperature is preferably 200 ° C, more preferably 150 ° C. The lower limit of the pre-bake time is preferably 10 seconds, and more preferably 30 seconds. As an upper limit of the above-mentioned time, 600 seconds are preferred and 300 seconds are more preferred.

Next, the resist film formed above is exposed by selective radiation irradiation. As the radiation used for the exposure, depending on the type of radiation-sensitive acid generator used in the resist composition, visible light, ultraviolet light, far ultraviolet light, X-rays, electromagnetic waves such as γ-rays; electron beams, molecular beams, It is appropriately selected from particle beams such as an ion beam. Among them, far ultraviolet rays are preferable, and KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ excimer laser light (wavelength 157 nm), Kr ₂ excimer laser light (wavelength 147 nm), and ArKr excimer laser light (Wavelength 134 nm) and extreme ultraviolet rays (wavelength 13.5 nm and the like, EUV) are more preferable, and KrF excimer laser light, ArF excimer laser light and EUV are further preferable.

  After the above exposure, post baking can be performed to improve resolution, pattern profile, developability, and the like. The temperature of the post-baking is appropriately adjusted according to the type of the resist composition used, etc., and the lower limit of the temperature is preferably 50 ° C., more preferably 70 ° C. The upper limit of the temperature is preferably 200 ° C, more preferably 150 ° C. The lower limit of the post-baking time is preferably 10 seconds, and more preferably 30 seconds. As an upper limit of the above-mentioned time, 600 seconds are preferred and 300 seconds are more preferred.

  Next, the exposed resist film is developed with a developer to form a resist pattern. This development may be an alkali development or an organic solvent development. As the developer, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyl Diethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [ 4.3.0] -5-nonene and the like. An appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, a surfactant, and the like can be added to these alkaline aqueous solutions. In the case of organic solvent development, examples of the developer include various organic solvents exemplified as the above-mentioned [B] solvent.

  After development with the above-mentioned developer, washing and drying are performed to form a predetermined resist pattern.

  As a method of performing the resist pattern forming step, a method using a nanoimprint method, a method using a self-assembled composition, or the like can be used other than the method using the above-described resist composition.

[Substrate pattern formation process]
In this step, a pattern is formed on the substrate by etching a plurality of times using the resist pattern as a mask. When the intermediate layer is not provided, etching is performed in the order of the resist underlayer film and the substrate. When the intermediate layer is provided, the etching is performed in the order of the intermediate layer, the resist underlayer film, and the substrate. Examples of the etching method include dry etching and wet etching. Among these, dry etching is preferable from the viewpoint of improving the shape of the substrate pattern. For this dry etching, for example, gas plasma such as oxygen plasma or the like is used. After the above etching, a substrate having a predetermined pattern is obtained.

<Resist underlayer film>
The resist underlayer film of the present invention is formed from the composition for forming a resist underlayer film. Since the resist underlayer film is formed from the above-described composition for forming a resist underlayer film, the resist underlayer film has excellent solvent resistance, etching resistance, heat resistance, and embedding property.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.

[Mw and Mn]
[A] The compound Mw and Mn were measured using Tosoh's GPC columns (two G2000HXL and one G3000HXL) at a flow rate of 1.0 mL / min, an eluting solvent of tetrahydrofuran, and a column temperature of 40 ° C. The measurement was performed by a gel permeation chromatograph (detector: differential refractometer) using monodisperse polystyrene as a standard under the analysis conditions described in (1).

[Average film thickness]
The average thickness of the film was measured using a spectroscopic ellipsometer (“M2000D” manufactured by JA WOLLAM).

<Synthesis of [A] compound>
[Synthesis Example 1]
In a three-necked flask equipped with a thermometer, condenser and mechanical stirrer, under nitrogen, 37.16 g (0.11 mol) of 9,9-bis (4-hydroxyphenyl) fluorene and 2.84 g (0.095 mol) of paraformaldehyde. Was charged. Next, 0.153 g (0.80 mmol) of p-toluenesulfonic acid monohydrate was dissolved in 58 g of propylene glycol monomethyl ether acetate (PGMEA). With stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of hexane, and the precipitated polymer was filtered to obtain a compound (PA-1).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (PA-1) obtained above, 80 g of N, N-dimethylacetamide and 16.68 g of potassium carbonate (0.1 g) were placed under nitrogen. 12 mol). Next, the mixture was heated to 80 ° C., and after adding 14.36 g (0.12 mol) of propargyl bromide, the mixture was stirred for 6 hours to carry out a reaction. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-1). Obtained. Mw of the obtained compound (A-1) was 4,500.

[Synthesis Example 2]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 37.75 g (0.084 mol) of 9,9-bis (hydroxynaphthyl) fluorene and 2.25 g (0.075 mol) of paraformaldehyde were charged under nitrogen. It is. Next, after dissolving 0.121 g (0.63 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of methanol, and the precipitated compound was filtered to obtain a compound (PA-2).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the polymer (PA-2) obtained above, 80 g of N, N'-dimethylacetamide and 13.09 g of potassium carbonate under nitrogen were added. 0.095 mol). Next, the mixture was heated to 80 ° C., and after adding 11.27 g (0.095 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-2). Obtained. Mw of the obtained compound (A-2) was 4,500.

[Synthesis Example 3]
A 3-neck flask equipped with a thermometer, a condenser and a mechanical stirrer was charged with 35.16 g (0.16 mol) of 1-hydroxypyrene and 4.84 g (0.16 mol) of paraformaldehyde under nitrogen. Next, after dissolving 0.245 g (1.29 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of methanol, and the precipitated compound was filtered to obtain a compound (PA-3).

  Next, in a three-necked flask equipped with a thermometer, a condenser, and a mechanical stirrer, 20 g of the compound (PA-3) obtained above, 80 g of N, N-dimethylacetamide, and 13.09 g of potassium carbonate (0. 095 mol). Next, the mixture was heated to 80 ° C., and after adding 11.27 g (0.095 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-3). Obtained. Mw of the obtained compound (A-3) was 5,400.

[Synthesis Example 4]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 26.42 g (0.075 mol) of 9,9-bis (4-hydroxyphenyl) fluorene, 10.19 g (0.050 mol) of pyrene and 3.40 g (0.113 mol) of paraformaldehyde was charged. Next, after dissolving 0.182 g (0.96 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of hexane, and the precipitated polymer was filtered to obtain a compound (PA-4).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (PA-4) obtained above, 80 g of N, N-dimethylacetamide and 11.96 g of potassium carbonate (0.1 g) were placed under nitrogen. 087 mol). Next, the mixture was heated to 80 ° C., and after adding 10.29 g (0.087 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-4). Obtained. Mw of the obtained compound (A-4) was 3,500.

[Synthesis Example 5]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 19.26 g (0.055 mol) of 9,9-bis (4-hydroxyphenyl) fluorene and 8.0 g of 1-hydroxypyrene (0. 037 mol), 8.62 g (0.092 mol) of phenol, and 4.13 g (0.137 mol) of paraformaldehyde. Next, after dissolving 0.30 g (1.58 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of a mixed solution of methanol / water (70/30 (mass ratio)), and the precipitated polymer was filtered to obtain a compound (PA-5).

  Next, in a three-necked flask equipped with a thermometer, a condenser, and a mechanical stirrer, 20 g of the compound (PA-5) obtained above, 80 g of N, N-dimethylacetamide, and 18.92 g of potassium carbonate (0. (137 mol). Next, the mixture was heated to 80 ° C., and after adding 16.29 g (0.137 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-5). Obtained. Mw of the obtained compound (A-5) was 7,600.

[Synthesis Example 6]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 16.15 g (0.046 mol) of 9,9-bis (4-hydroxyphenyl) fluorene and 6.7 g of 1-hydroxypyrene (0.06 mol) under nitrogen. 031 mol), 13.69 g (0.077 mol) of anthracene and 3.46 g (0.115 mol) of paraformaldehyde. Next, after dissolving 0.182 g (0.96 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of a mixed solution of methanol / water (70/30 (mass ratio)), and the precipitated polymer was filtered to obtain a compound (PA-6).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (PA-6) obtained above, 80 g of N, N-dimethylacetamide and 18.92 g of potassium carbonate (0.10 g) were placed under nitrogen. (137 mol). Next, the mixture was heated to 80 ° C., and after adding 16.29 g (0.137 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-6). Obtained. Mw of the obtained compound (A-6) was 3,200.

[Synthesis Example 7]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, under nitrogen, 9.09 g (0.049 mol) of 9,9-bis (4-hydroxyphenyl) fluorene and 7.09 g (0.09 g) of 1-hydroxypyrene. 032 mol), 11.71 g (0.081 mol) of 1-naphthol, and 4.14 g (0.138 mol) of paraformaldehyde. Next, after dissolving 0.266 g (1.4 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of a mixed solution of methanol / water (70/30 (mass ratio)), and the precipitated polymer was filtered to obtain a compound (PA-7).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (PA-7) obtained above, 80 g of N, N-dimethylacetamide and 16.90 g of potassium carbonate (0.1 g) were placed under nitrogen. 122 mol). Next, the mixture was heated to 80 ° C., and 14.55 g (0.122 mol) of propargyl bromide was added, followed by stirring for 6 hours to carry out a reaction. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-7). Obtained. Mw of the obtained compound (A-7) was 3,900.

[Synthesis Example 8]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, under nitrogen, 9.49 g (0.061 mol) of 9,9-bis (4-hydroxyphenyl) fluorene, 12.41 g (0.061 mol) of pyrene, 2.89 g (0.031 mol) of phenol and 3.22 g (0.107 mol) of paraformaldehyde were charged. Next, after dissolving 0.251 g (1.32 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the reaction solution was poured into a large amount of a mixed solution of methanol / water (70/30 (mass ratio)), and the precipitated polymer was filtered to obtain a compound (PA-8).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (PA-8) obtained above, 80 g of N, N-dimethylacetamide, and 11.99 g of potassium carbonate (0.1 g) under nitrogen. 087 mol). Next, the mixture was heated to 80 ° C., and after adding 10.32 g (0.087 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-8). Obtained. Mw of the obtained compound (A-8) was 5,600.

[Synthesis Example 9]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, under nitrogen, 9.57 g (0.027 mol) of 9,9-bis (4-hydroxyphenyl) fluorene and 3.97 g (0.07 mol) of 1-hydroxypyrene. 018 mol), 6.56 g (0.046 mol) of 1-naphthol and 19.9 g (0.086 mol) of 1-formylpyrene. Next, after dissolving 5.19 g (27.3 mmol) of p-toluenesulfonic acid monohydrate in 58 g of γ-butyrolactone, this solution was charged into a three-necked flask, and stirred at 130 ° C. for 9 hours. Polymerized. Thereafter, the reaction solution was poured into a large amount of a mixed solution of methanol / water (70/30 (mass ratio)), and the precipitated polymer was filtered to obtain a compound (PA-9).

  Next, in a three-necked flask equipped with a thermometer, a condenser, and a mechanical stirrer, 20 g of the compound (PA-9) obtained above, 80 g of N, N-dimethylacetamide, and 18.92 g of potassium carbonate (0. (137 mol). Next, the mixture was heated to 80 ° C., and after adding 16.29 g (0.137 mol) of propargyl bromide, the mixture was stirred and reacted for 6 hours. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. The organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (A-9). Obtained. Mw of the obtained compound (A-9) was 1,500.

[Synthesis Example 10]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 26.42 g (0.075 mol) of 9,9-bis (4-hydroxyphenyl) fluorene, 10.19 g (0.050 mol) of pyrene and 3.40 g (0.113 mol) of paraformaldehyde was charged. Next, after dissolving 0.182 g (0.96 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of hexane, and the precipitated compound was filtered to obtain a compound (Pa-1).

  Next, in a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, 20 g of the compound (Pa-1), 80 g of N, N-dimethylacetamide and 11.96 g (0.087 mol) of potassium carbonate were charged under nitrogen. It is. Next, the mixture was heated to 80 ° C., and 11.68 g (0.087 mol) of 4-bromo-1-butene was added, followed by stirring for 6 hours to carry out a reaction. Thereafter, 40 g of methyl isobutyl ketone and 80 g of water were added to the reaction solution to carry out a liquid separation operation. Then, the organic phase was poured into a large amount of methanol, and the precipitated compound was filtered to obtain the compound (a-1). Obtained. Mw of the obtained compound (a-1) was 4,000.

[Synthesis Example 11]
In a three-necked flask equipped with a thermometer, a condenser, and a mechanical stirrer, under nitrogen, 25.83 g (0.074 mol) of 9,9-bis (4-hydroxyphenyl) fluorene, 9.96 g (0.049 mol) of pyrene and 4.21 g (0.14 mol) of paraformaldehyde was charged. Next, after dissolving 0.20 g (1.05 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of methanol, and the precipitated compound was filtered to obtain a compound (CA-1). Mw of the obtained compound (CA-1) was 11,000.

[Synthesis Example 12]
In a three-necked flask equipped with a thermometer, a condenser and a mechanical stirrer, under nitrogen, 18.18 g (0.083 mol) of 1-hydroxypyrene, 12.85 g (0.089 mol) of 1-naphthol, and 3.35 g (0. 0.036 mol) and 5.62 g (0.19 mol) of paraformaldehyde. Next, after dissolving 0.30 g (1.58 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solution of methanol / water (90/10 (mass ratio)), and the precipitated compound was filtered to obtain a compound (CA-2). Mw of the obtained compound (CA-2) was 5,800.

[Synthesis Example 13]
In a three-necked flask equipped with a thermometer, a condenser, and a mechanical stirrer, 49.54 g (0.11 mol) of 9,9-bis (hydroxynaphthyl) fluorene and 2.84 g (0.095 mol) of paraformaldehyde were charged under nitrogen. It is. Next, after dissolving 0.153 g (0.80 mmol) of p-toluenesulfonic acid monohydrate in 58 g of propylene glycol monomethyl ether acetate (PGMEA), this solution was charged into a three-necked flask, and heated at 95 ° C. Polymerization was carried out with stirring for 6 hours. Thereafter, the polymerization reaction solution was poured into a large amount of methanol, and the precipitated compound was filtered to obtain a compound (CA-3). Mw of the obtained compound (CA-3) was 5,200.

<Preparation of composition for forming resist underlayer film>
Components other than the polymer [A] used for preparing the composition for forming a resist underlayer film are shown below.

[[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))

[Example 1]
[A] 5 parts by mass of (A-1) as a polymer was dissolved in 95 parts by mass of (B-1) as a solvent [B]. The resulting solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resist underlayer film forming composition (J-1).

[Examples 2 to 13, Reference Example 1 and Comparative Examples 1 to 3]
Each composition for forming a resist underlayer film was prepared in the same manner as in Example 1 except that the components and amounts shown in Table 1 were used. In Table 1, "-" indicates that the corresponding component was not used.

[Examples 14 to 31, Reference Example 2 and Comparative Examples 4 to 9]
(Formation of resist underlayer film)
Each of the prepared compositions for forming a resist underlayer film was applied on a silicon wafer substrate by a spin coating method. Thereafter, the substrate was heated (baked) at 220 ° C. for 60 seconds in an air atmosphere to form a resist underlayer film having a thickness of 200 nm, and a substrate with a resist underlayer film having a resist underlayer film formed on the substrate was obtained. Examples 14 to 26 and Comparative Examples 4 to 6). [A] The composition for forming a resist underlayer film (j-1) prepared in Reference Example 1 in which the compound has no group having a carbon-carbon triple bond and has a group having a carbon-carbon double bond When was used, it was referred to as Reference Example 2. The compositions (J-9) to (J-13) and (CJ-1) to (CJ-3) for forming a resist underlayer film prepared in Examples 9 to 13 and Comparative Examples 1 to 3 were 400 Substrates with a resist underlayer film heated (baked) at 90 ° C. for 90 seconds were also obtained (Examples 27 to 31 and Comparative Examples 7 to 9).

(Formation of resist underlayer film on stepped substrate)
Each of the prepared compositions for forming a resist underlayer film was applied to a 70 nm CH, 500 nm depth silicon wafer stepped substrate (substrate to be processed) by a spin coating method. Thereafter, the substrate was heated (baked) at 220 ° C. for 60 seconds in an air atmosphere to form a resist underlayer film having a thickness of 200 nm, thereby obtaining step substrates with a resist underlayer film having a resist underlayer film formed on a substrate. (Examples 14 to 26 and Comparative Examples 4 to 6). The compositions (J-9) to (J-13) and (CJ-1) to (CJ-3) for forming a resist underlayer film prepared in Examples 9 to 13 and Comparative Examples 1 to 3 were 400 Step substrates with a resist underlayer film heated (baked) at 90 ° C. for 90 seconds were also obtained (Examples 27 to 31 and Comparative Examples 7 to 9).

<Evaluation>
Various evaluations were performed on the obtained substrate with a resist underlayer film and the stepped substrate with a resist underlayer film according to the following procedures. Table 2 shows the evaluation results. "-" In Table 2 indicates that evaluation was not performed because the performance of the resist underlayer film was low and evaluation was difficult.

[Solvent resistance]
The obtained substrate with a resist underlayer film was immersed in cyclohexanone (room temperature) for 1 minute. The average film thickness before and after immersion was measured, and the absolute value of the numerical value obtained by (X−X0) × 100 / X0 was calculated, where X0 is the average film thickness before immersion, and X is the average film thickness after immersion. The thickness change rate (%) was used. The solvent resistance is “A” (good) when the film thickness change rate is less than 1%, “B” (slightly good) when it is 1% or more and less than 5%, and “C” when it is 5% or more. (Poor).

[Etching resistance]
Using the etching apparatus ("TACTRAS" manufactured by Tokyo Electron Ltd.), CF ₄ / Ar = 110/440 sccm, PRESS. = 30 MT, HF RF = 500 W, LF RF = 3000 W, DCS = -150 V, RDC = 50%, 30 sec, and calculated (nm / min) from the average film thickness before and after the process. The ratio was calculated. The etching resistance is “A” (very good) when the ratio is 0.95 or more and less than 0.98, and “B” (good) when the ratio is 0.98 or more and less than 1.00. Was evaluated as "C" (defective).

[Heat-resistant]
The above prepared composition for forming a resist underlayer film was spin-coated on a silicon wafer having a diameter of 8 inches to form a resist underlayer film, and then the resist underlayer film was heated at 400 ° C. for 150 seconds. After the powder was recovered from the substrate, the mass loss (%) when heated at a rate of 10 ° C./min in a nitrogen atmosphere using a TG-DTA apparatus was defined as heat resistance. The smaller the heat resistance value, the smaller the sublimate and the decomposition product of the resist underlayer film generated when the resist underlayer film is heated, indicating good (high heat resistance). The heat resistance is “A” (very good) when the above-mentioned mass loss rate is 0% or more and less than 5%, “B” (good) when it is 5% or more and less than 10%, and 10% or more. Was evaluated as "C" (poor).

[Embedding property]
The resulting step substrate with a resist underlayer film was evaluated for the presence or absence of voids. Those with no voids were rated "A" (good), and those with voids were rated "B" (poor).

  As can be seen from the results in Table 2, according to the composition for forming a resist underlayer film of Example, PGMEA or the like can be used as a solvent, and a resist underlayer film having excellent solvent resistance, etching resistance, heat resistance, and embedding property can be obtained. Can be formed.

  According to the composition for forming a resist underlayer film of the present invention, PGMEA or the like can be used as a solvent, and a resist underlayer film having excellent solvent resistance, etching resistance, heat resistance, and embedding property can be formed. The resist underlayer film of the present invention is excellent in solvent resistance, etching resistance, heat resistance and burying property. According to the method for manufacturing a patterned substrate of the present invention, a patterned substrate having an excellent pattern shape can be obtained by using the formed excellent resist underlayer film. Therefore, they can be suitably used for the manufacture of semiconductor devices, which are expected to be further miniaturized in the future.

Claims (11)

A compound having a group containing a carbon-carbon triple bond and having a partial structure containing an aromatic ring, wherein the total number of benzene nuclei constituting the aromatic ring in the partial structure is 4 or more; and a solvent. And
A composition for forming a resist underlayer film having a first partial structure represented by the following formula (1) as the partial structure .

(In the formula (1), R ^{1 to} R ⁴ are each independently a hydrogen atom, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. R ^At least one of ^{1 to} R ^{4 is} a monovalent group containing a carbon-carbon triple bond, m1 and m2 are each independently an integer of 0 to 2. a1 and a2 are each independently It is an integer of 0 to 9. n1 and n2 are each independently an integer of 0 to 2. a3 and a4 are each independently an integer of 0 to 8. R ^{1 to} R ⁴ are each an integer of 0 to 8. In the case of a plurality of R ¹ , a plurality of R ¹ may be the same or different, a plurality of R ² may be the same or different, a plurality of R ³ may be the same or different, and a plurality of R ⁴ may be the same P1 and p2 are each independently an integer of 0 to 9; P3 and p4 are each independently an integer from 0 to 8. p1 + p2 + p3 + p4 is not less than 1. a1 + p1 and a2 + p2 are each not more than 9. a3 + p3 and a4 + p4 are each not more than 8. It shows a binding site with a part other than the partial structure represented by the formula (1) in the compound. The composition for forming a resist underlayer film according to claim 1, wherein the monovalent group containing a carbon-carbon triple bond is a propargyl group. The composition for forming a resist underlayer film according to claim 1 or 2 , wherein the composition has a second partial structure represented by the following formula (2) as the partial structure.

(In the formula (2), R ^{5 to} R ⁸ each independently represent an alkyl group, a hydroxy group, an alkoxy group, a monovalent group containing a carbon-carbon triple bond, or a monovalent group containing a carbon-carbon double bond. B1 and b3 are each independently an integer of 0 to 2. b2 and b4 are each independently an integer of 0 to 3. R ^{5 to} R ⁸ are each a plurality of groups. In this case, a plurality of R ⁵ may be the same or different, a plurality of R ⁶ may be the same or different, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different. Q1 and q3 are each independently an integer of 0 to 2. q2 and q4 are each independently an integer of 0 to 3. q1 + q2 + q3 + q4 is equal to or greater than 0. b1 + q1 and b3 + q3. Is not more than 2. b2 + Q2 and b4 + q4 are each equal to or less than 3. * indicates a binding site to a portion of the compound other than the partial structure represented by the formula (2).) The composition for forming a resist underlayer film according to claim 3 , wherein the compound has the first partial structure and the second partial structure. The resist underlayer film formation according to claim 3 or 4 , wherein q1 + q2 + q3 + q4 in the formula (2) is 1 or more, and at least one of R ^{5 to} R ^{8 is} a monovalent group containing a carbon-carbon triple bond. Composition. 6. The composition for forming a resist underlayer film according to claim 5 , wherein the monovalent group containing a carbon-carbon triple bond is a propargyloxy group. The resist underlayer film formation according to any one of claims 1 to 6 , wherein the compound has a plurality of the partial structures, and the plurality of partial structures are bonded via a linking group derived from an aldehyde. Composition. The composition for forming a resist underlayer film according to any one of claims 1 to 7 , wherein the compound has a molecular weight of 1,000 or more and 10,000 or less. The composition for forming a resist underlayer film according to any one of claims 1 to 8 , wherein the solvent includes a polyhydric alcohol partially ether acetate-based solvent. A resist underlayer film formed from the composition for forming a resist underlayer film according to claim 1 . Forming a resist underlayer film on one side of the substrate,
A step of forming a resist pattern on the side of the resist underlayer film opposite to the substrate, and a step of forming a pattern on the substrate by performing etching multiple times using the resist pattern as a mask
A method for producing a patterned substrate, wherein the resist underlayer film is formed using the composition for forming a resist underlayer film according to any one of claims 1 to 9 .