RESIST UNDERLAYER FILM-FORMING COMPOSITION

Abstract

A polymer to which there is attached a group represented by the following formula (1):

##STR00001##

(wherein each of R.sub.x, S.sub.y, and S.sub.z represents a hydrogen atom or a monovalent organic group; each of R.sub.y and R.sub.z represents a single bond or a divalent organic group; each of ring Ar.sub.y and ring Ar.sub.z represents a C4 to C20 cyclic alkyl group or a C6 to C30 aryl group, and ring Ar.sub.y and ring Ar.sub.z may be linked together to form a new ring structure therebetween; n.sub.y is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.y; n.sub.z is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.z; and * is a polymer bonding site).

Claims

1. A resist underlayer film-forming composition containing a polymer to which there is attached a group represented by the following formula (1): ##STR00046## (wherein each of R.sub.x, S.sub.y, and S.sub.z represents a hydrogen atom or a monovalent organic group; each of R.sub.y and R.sub.z, represents a single bond or a divalent organic group; each of ring Ar.sub.y and ring Ar.sub.z represents a C4 to C20 cyclic alkyl group or a C6 to C30 aryl group, and ring Ar.sub.y and ring Ar.sub.z may be linked together to form a new ring structure therebetween; n.sub.y is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.y; n.sub.z is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.t; and * is a polymer bonding site).

2. The resist underlayer film-forming composition according to claim 1, wherein at least one of ring Ar.sub.y and ring Ar.sub.z includes a C6 to C30 aryl group.

3. The resist underlayer film-forming composition according to claim 1, wherein the group represented by formula (1) is at least one group selected from among the following formulas (1-1) to (1-15): ##STR00047## ##STR00048## ##STR00049## (wherein * is a polymer bonding site).

4. The resist underlayer film-forming composition according to claim 1, wherein the polymer includes at least one of a unit represented by the following formula (1a) and a unit represented by the following formula (1b): ##STR00050## (wherein each of AU represents a group represented by formula (1); each of R.sub.1 represents a halogen group, a nitro group, an amino group, a hydroxyl group, a glycidyl ether group, an aromatic hydrocarbyl group, a C1 to C10 alkyl group, or a C2 to C10 alkenyl group and may include at least one of an ether group, a ketone group, and an ester group; each of R.sub.2 represents a hydrogen atom, an aromatic hydrocarbyl group, or a heterocyclic group; each of R.sub.3 represents a hydrogen atom, an aromatic hydrocarbyl group, a heterocyclic group, a C1 to C10 alkyl group, or a C2 to C10 alkenyl group; each of the aromatic hydrocarbyl group and the heterocyclic group of R.sub.2 and R.sub.3 may have at least one substituent selected from among a halogen group, a nitro group, an amino group, a formyl group, a carboxyl group, an alkyl carboxylate ester group, a hydroxyl group, a C1 to C10 alkyl group, a C1 to C10 alkoxy group, and a C6 to C40 aryl group; R.sub.2 and R.sub.3 may be linked together to form a ring structure; each of ring Ar.sub.1 represents a benzene ring, a naphthalene ring, or an anthracene ring; ring Ar.sub.2 is a heterocyclic ring; each of n is an integer of ≥1; each of n.sub.1 is an integer of ≥0; and each of n+n.sub.1 is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.1).

5. The resist underlayer film-forming composition according to claim 1, wherein the polymer is a novorak resin.

6. The resist underlayer film-forming composition according to claim 1, wherein the polymer includes a unit represented by the following formula (1a-1) and/or a unit represented by the following formula (1a-2): ##STR00051## (wherein each of AU represents a group represented by formula (1); each of R.sub.1 represents a halogen group, a nitro group, an amino group, an aromatic hydrocarbyl group, a C1 to C10 alkyl group, or a C2 to C6 alkenyl group; each of R.sub.2 represents an aromatic hydrocarbyl group or a heterocyclic group; each of R.sub.3 represents a hydrogen atom, a phenyl group, or a naphthyl group; when each of R.sub.2 and R.sub.3 is a phenyl group, they may be linked together to form a fluorene ring; each of R.sub.4 represents a hydrogen atom, an acetal group, an acyl group, a glycidyl group, a C1 to C10 alkyl group, or a C2 to C6 alkenyl group; ring Ar.sub.1 is a benzene ring; each of X is a benzene ring, and two —C(CH.sub.3).sub.2— groups bonding to the benzene ring are in m- or p- relation; each of n.sub.1 is 0 or 1; the sum n.sub.a+n.sub.b is independently an integer of ≥1; and each of the sum n.sub.a+n.sub.i and the sum n.sub.b+n.sub.1 is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.1).

7. The resist underlayer film-forming composition according to claim 1, wherein the polymer includes a polymer represented by the following formula (1a-3): ##STR00052## (wherein each of AU represents a group represented by formula (1); each of R.sub.1 represents a halogen group, a nitro group, an amino group, a hydroxyl group, a C6 to C40 aromatic hydrocarbyl group, a C1 to C10 alkyl group, or a C2 to C10 alkenyl group, and may include at least one of an ether group, a ketone group, and an ester group; R.sub.2 represents a heterocyclic group or a C6 to C40 aromatic hydrocarbyl group, and the heterocyclic group or the aromatic hydrocarbyl group may have at least one substituent selected from among a halogen group, a nitro group, an amino group, a formyl group, a carboxyl group, a hydroxyl group, a C1 to C10 alkyl group, a C1 to C10 alkoxy group, and a C6 to C40 aryl group; R.sub.3 represents a hydrogen atom, a heterocyclic group, a C6 to C40 aromatic hydrocarbyl group, a C1 to C10 alkyl group, or a C2 to C10 alkenyl group, and the heterocyclic group, the aromatic hydrocarbyl group, the alkyl group, or the alkenyl group may have at least one substituent selected from among a halogen group, a nitro group, an amino group, and a hydroxyl group; R.sub.2 and R.sub.3 may be linked together to form a ring structure; R.sub.5 represents at least one member selected from among a hydrogen atom, a C1 to C10 alkyl group, a C2 to C10 alkenyl group, and a C6 to C40 aryl group and may include at least one of an ether group, a ketone group, and an ester group; each of ring Ar.sub.1 represents a benzene ring or a naphthalene ring; each of n.sub.1 is an integer of 0 to 3; the sum n.sub.a+n.sub.b is independently an integer of ≥1; and each of the sum n.sub.a+n.sub.1 and the sum n.sub.b+n.sub.1 is an integer of 0 to the maximum number corresponding to allowable substitution to ring An).

8. The resist underlayer film-forming composition according to claim 1, wherein the polymer includes a polymer represented by the following formula (1b-1): ##STR00053## (wherein each of AU represents a group represented by formula (1); each of R.sub.1 represents a halogen group, a nitro group, an amino group, a hydroxyl group, a C6 to C40 aromatic hydrocarbyl group, a C1 to C10 alkyl group, or a C2 to C10 alkenyl group, and may include at least one of an ether group, a ketone group, and an ester group; R.sub.2 represents a hydrogen atom, a heterocyclic group, or a C6 to C40 aromatic hydrocarbyl group; the heterocyclic group or the aromatic hydrocarbyl group may have at least one substituent selected from among a halogen group, a nitro group, an amino group, a formyl group, a carboxyl group, an alkyl carboxylate ester group, a phenyl group, a hydroxyl group, a C1 to C10 alkoxy group, and a C6 to C40 aryl group; R.sub.3 represents a hydrogen atom, a heterocyclic group, a C6 to C40 aromatic hydrocarbyl group, or a C1 to C10 alkyl group; R.sub.2 and R.sub.3 may be linked together to form a ring structure; ring Ar.sub.1 represents a benzene ring, a naphthalene ring, or an anthracene ring; R.sub.5 represents at least one member selected from among a hydrogen atom, a C1 to C10 alkyl group, a C2 to C10 alkenyl group, and a C6 to C40 aryl group and may include at least one of an ether group, a ketone group, and an ester group; the sum n.sub.a+n.sub.b is independently an integer of ≥1; each of n.sub.1 and n.sub.3 is an integer of ≥0; each of the sum n.sub.a+n.sub.1 and the sum n.sub.b+n.sub.1 is an integer of 0 to the maximum number corresponding to allowable substitution to ring Ar.sub.1; and n.sub.3 is an integer of 0 to the maximum number corresponding to allowable substitution to the R.sub.1-bound heterocyclic ring).

9-11. (canceled)

12. The method for producing a patterned substrate, the method comprising a step of forming a resist underlayer film on a substrate by use of a resist underlayer film-forming composition as recited in claim 1; a step of forming a specific hard mask on the resist underlayer film; a step of forming a photoresist film on the hard mask; a step of forming a resist pattern through light exposure to and development of the photoresist film; a step of mask-patterning by etching the hard mask through the resist pattern; a step of forming a resist underlayer pattern by etching the resist underlayer film through the mask pattern; and a step of processing the substrate through the resist underlayer pattern.

13. The method for producing a semiconductor device, the method comprising a step of forming a resist underlayer film on a substrate by use of a resist underlayer film-forming composition as recited in claim 1; a step of etching the resist underlayer film through a specific pattern, and a step of processing the substrate through the patterned resist underlayer film.

Description

EXAMPLES

[0093] The present invention will next be described by way of Examples and Comparative Examples. However, the present invention should not be limited by the following description.

[0094] In Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 and 2, the weight average molecular weight (Mw) as reduced to polystyrene and the polydispersity (Mw/Mn) were determined through gel permeation chromatography (GPC). The chromatographic measurement was performed by means of a GPC (product of Tosoh Corp.) under the following conditions. GPC column: TSKgel SuperMultipore (registered trademark) Hz-N (product of Tosoh) [0095] Column temperature: 40° C. [0096] Solvent: tetrahydrofuran (THF) [0097] Flow rate: 0.35 mL/min [0098] Standard sample: polystyrene (product of Tosoh)

[0099] The following abbreviations are employed in the Examples and Comparative Examples. [0100] DPM: benzhydrol [0101] TPM: triphenylmethanol [0102] DP: 1,1-diphenyl-2-propyn-1-ol [0103] TP: 1,1,3-triphenyl-2-propyn-1-ol [0104] FLO: 9-fluorenol

##STR00045## [0105] PGME: propylene glycol monomethyl ether [0106] PGMEA: propylene glycol monomethyl ether acetate

<Synthesis of Polymers>

Synthesis Example 1

[0107] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (BPM) (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (Py) (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature, and TMP (3.76 g, 0.0144 mol, product of Tokyo Chemical Industry Co., Ltd.) and methanesulfonic acid (0.2774 g, 0.0029 mol, product of Tokyo Chemical Industry Co., Ltd.) were added thereto. Then, PGME (1.82 g, product of Kanto Chemical Co., Inc.) and PGMEA (4.24 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 23 hours after initiation of reaction. Subsequently, the product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 16.12 g of a polymer (BPM-Py-TPM). The thus-obtained BPM-Py-TPM was found to have a weight average molecular weight (Mw) of 18,260 and a polydispersity (Mw/Mn) of 12.85.

Synthesis Example 2

[0108] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature, and DP (3.01g, 0.0144 mol, product of Tokyo Chemical Industry Co., Ltd.) and methanesulfonic acid (0.2774 g, 0.0029 mol, product of Tokyo Chemical Industry Co., Ltd.) were added thereto. Then, PGME (1.82 g, product of Kanto Chemical Co., Inc.) and PGMEA (4.24 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 23 hours after initiation of reaction. Subsequently, the product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 13.56 g of a polymer (BPM-Py-DP). The thus-obtained BPM-Py-DP was found to have a weight average molecular weight (Mw) of 22,380 and a polydispersity (Mw/Mn) of 12.61.

Synthesis Example 3

[0109] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature, and TP (4.10 g, 0.0144 mol, product of Tokyo Chemical Industry Co., Ltd.) and methanesulfonic acid (0.2774 g, 0.0029 mol, product of Tokyo Chemical Industry Co., Ltd.) were added thereto. Then, PGME (1.82 g, product of Kanto Chemical Co., Inc.) and PGMEA (4.24 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 23 hours after initiation of reaction. Subsequently, the product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 13.48 g of a polymer (BPM-Py-TP). The thus-obtained BPM-Py-TP was found to have a weight average molecular weight (Mw) of 3,490 and a polydispersity (Mw/Mn) of 2.50.

Synthesis Example 4

[0110] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature, and FLO (2.63 g, 0.0144 mol, product of Tokyo Chemical Industry Co., Ltd.) and methanesulfonic acid (0.2774 g, 0.0029 mol, product of Tokyo Chemical Industry Co., Ltd.) were added thereto. Then, PGME (1.82 g, product of Kanto Chemical Co., Inc.) and PGMEA (4.24 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 23 hours after initiation of reaction. Subsequently, the product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 14.07 g of a polymer (BPM-Py-FLO). The thus-obtained BPM-Py-FLO was found to have a weight average molecular weight (Mw) of 6,720 and a polydispersity (Mw/Mn) of 3.11.

Synthesis Example 5

[0111] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature, and DPM (2.66 g, 0.0144 mol, product of Tokyo Chemical Industry Co., Ltd.) and methanesulfonic acid (0.2774 g, 0.0029 mol, product of Tokyo Chemical Industry Co., Ltd.) were added thereto. Then, PGME (1.82 g, product of Kanto Chemical Co., Inc.) and PGMEA (4.24 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 23 hours after initiation of reaction. Subsequently, the product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 12.16 g of a polymer (BPM-Py-DPM). The thus-obtained BPM-Py-DPM was found to have a weight average molecular weight (Mw) of 15,080 and a polydispersity (Mw/Mn) of 12.11.

Synthesis Example 6

[0112] Under nitrogen, 2-phenylindole (8.00 g, 0.0414 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (9.533 g, 0.0414 mol, product of Aldrich), TMP (4.31 g, 0.0166 mol, product of Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (1.6711 g, mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (16.46 g, product of Kanto Chemical Co., Inc.) and PGMEA (38.41 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 16.38 g of a polymer (Pid-Py-TPM). The thus-obtained Pid-Py-TPM was found to have a weight average molecular weight (Mw) of 780 and a polydispersity (Mw/Mn) of 2.00.

Synthesis Example 7

[0113] Under nitrogen, 1-phenyl-2-naphtylamine (8.00 g, 0.0365 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (8.406 g, 0.0365 mol, product of Aldrich), TMP (3.80 g, 0.0146 mol, product of Tokyo Chemical Industry Co., Ltd.), and methanesulfonic acid (1.4727 g, 0.0153 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, 1,4-dioxane (32.51 g, product of Kanto Chemical Co., Inc.) was fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 16.36 g of a polymer (PNA-Py-TPM). The thus-obtained PNA-Py-TPM was found to have a weight average molecular weight (Mw) of 1,495 and a polydispersity (Mw/Mn) of 2.63.

Comparative Synthesis Example 1

[0114] Under nitrogen, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (10.00 g, 0.0289 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (6.646 g, 0.0289 mol, product of Aldrich), and methanesulfonic acid (0.5548 g, 0.0058 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (7.74 g, product of Kanto Chemical Co., Inc.) and PGMEA (18.06 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 24 hours after initiation of reaction. The product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 10.82 g of a polymer (BPM-Py). The thus-obtained BPM-Py was found to have a weight average molecular weight (Mw) of 6,300 and a polydispersity (Mw/Mn) of 1.90.

Comparative Synthesis Example 2

[0115] Under nitrogen, 2-phenylindol (Pid) (8.00 g, 0.0414 mol, product of Tokyo Chemical Industry Co., Ltd.), 1-pyrenecarboxyaldehyde (9.533 g, 0.0414 mol, product of Aldrich), and methanesulfonic acid (1.1937 g, 0.0124 mol, product of Tokyo Chemical Industry Co., Ltd.) were added to a four-neck flask (300 mL). Then, PGME (13.11 g, product of Kanto Chemical Co., Inc.) and PGMEA (30.59 g, product of Kanto Chemical Co., Inc.) were fed to the flask. The mixture was heated to 120° C. under stirring, to thereby dissolve it and initiate polymerization reaction. The polymerization reaction was terminated 20 hours after initiation of reaction. The product was allowed to cool to room temperature and reprecipitated in methanol (500 g, product of Kanto Chemical Co., Inc.). The precipitated matter was separated through filtration and dried at 50° C. for 10 hours by means of a vacuum drier, to thereby yield 16.38 g of a polymer (Pid-Py). The thus-obtained Pid-Py was found to have a weight average molecular weight (Mw) of 880 and a polydispersity (Mw/Mn) of 1.69.

<Preparation of Resist Underlayer Film-Forming Compositions>

Example 1

[0116] The polymer produced in Synthesis Example 1 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 2

[0117] The polymer produced in Synthesis Example 2 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 3

[0118] The polymer produced in Synthesis Example 3 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 4

[0119] The polymer produced in Synthesis Example 4 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 5

[0120] The polymer produced in Synthesis Example 5 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 6

[0121] The polymer produced in Synthesis Example 6 (1.227 g) was mixed with 4,4′-(1-methylethylidine)bis[2,6-bis[(2-methoxy-1-methylethoxy)methyl]-phenol (0.184 g) as a cross-linking agent, pyridinium p-phenolsulfonate (0.018 g) as an acidic compound, and Megaface R-30N (product of DIC Corporation) (0.0012 g) as a surfactant. The mixture was dissolved in PGME (3.53 g), PGMEA (3.53 g), and cyclohexanone (10.58 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Example 7

[0122] The polymer produced in Synthesis Example 7 (1.227 g) was mixed with 4,4′-(1-methylethylidine)bis[2,6-bis[(2-methoxy-1-methylethoxy)methyl]-phenol (0.184 g) as a cross-linking agent, pyridinium p-phenolsulfonate (0.018 g) as an acidic compound, and Megaface R-30N (product of DIC Corporation) (0.0012 g) as a surfactant. The mixture was dissolved in PGME (3.53 g), PGMEA (3.53 g), and cyclohexanone (10.58 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Comparative Example 1

[0123] The polymer produced in Comparative Synthesis Example 1 (20 g) was mixed with Megaface R-30N (product of DIC Corporation) (0.06 g) as a surfactant. The mixture was dissolved in PGME (24 g) and PGMEA (66 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Comparative Example 2

[0124] The polymer produced in Comparative Synthesis Example 2 (1.227 g) was mixed with 3,3′,5,5′-tetramethoxymethyl-4,4′-dihydroxybiphenyl (TMOM-BP, product of Honshu Chemical Industry Co., Ltd.) (0.184 g) as an acid-generator, pyridinium p-phenolsulfonate (0.018 g) as an acidic compound, and Megaface R-30N (product of DIC Corporation) (0.0012 g) as a surfactant. The mixture was dissolved in PGME (3.53 g), PGMEA (3.53 g), and cyclohexanone (10.58 g). Subsequently, the product was filtered sequentially through a polyethylene microfilter (pore size: 0.10 μm) and a polyethylene microfilter (pore size: 0.05 μm), to thereby prepare a resist underlayer film-forming composition.

Examples 1A to 7A, and Comparative Examples 1A and 2A)

[0125] Each of the resist underlayer film-forming compositions prepared in Examples 1 to 7 and Comparative Examples 1 and 2 was applied onto a silicon wafer by means of a spin coater. The coated wafer was baked with a hot plate at 400° C. for 90 seconds, to thereby form a resist underlayer film (film thickness: 0.25 μm).

<Photoresist Solvent Elution Test>

[0126] Each of the resist underlayer films formed in Examples 1A to 7A and Comparative Examples 1A and 2A was immersed in a solvent employable in a photoresist solution, specifically, each of ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and cyclohexanone. The test has revealed that all the films are insoluble in the tested solvents. The solubility (or insolubility) was determined on the basis of the change in film thickness as measured before and after the elution test.

<Measurement of Dry Etching Rate>

[0127] The following etcher and etching gas were used in the measurement of dry etching rate. [0128] Etcher: ES401 (product of Nippon Scientific Co., Ltd.) [0129] Etching gas: CF.sub.4

[0130] The dry etching rate (speed) of each of the resist underlayer films formed in Examples 1A to 7A and Comparative Examples 1A and 2A was determined by use of a halogen-containing etching gas (specifically CF.sub.4) as an etching gas. The decrease in film thickness per unit time (1 minute) with respect to each resist underlayer film was calculated as a dry etching rate. Table 1 shows the results. The smaller the dry etching rate, the higher the etching resistance to CF.sub.4 gas.

TABLE-US-00001 TABLE 1 Decrease in film thickness per unit time (Å/min) Ex. 1A 79.4 Ex. 2A 78.2 Ex. 3A 78.2 Ex. 4A 78.2 Ex. 5A 79.4 Ex. 6A 73.5 Ex. 7A 76.1 Comp. Ex. 1A 81.6 Comp. Ex. 2A 84.9

[0131] The resist underlayer films formed in Examples 1 A to 7A have high etching resistance to CF.sub.4 gas. Thus, the films are expected to exhibit a higher dry etching rate with respect to an oxygen-based or hydrogen-based gas (having an etching selectivity differing from that of a halogen-containing etching gas), as compared with the resist underlayer films formed in Comparative Examples 1A and 2A.

<Chemical Liquid Mixing Test>

[0132] Each of the resist underlayer film-forming compositions prepared in Examples 1 to 7 and Comparative Examples 1 and 2 was mixed with methyl 2-hydroxyisobutyratea at a weight ratio of 9:1. The presence of precipitates in the mixture was checked. Table 2 shows the results. The precipitates were visually observed and confirmed. When the solution was transparent, the test score was “no precipitation,” whereas when the solution contained insoluble matter, the test score was “precipitation.”

TABLE-US-00002 TABLE 2 Presence of precipitation after mixing Ex. 1 no precipitation Ex. 2 no precipitation Ex. 3 no precipitation Ex. 4 no precipitation Ex. 5 no precipitation Ex. 6 no precipitation Ex. 7 no precipitation Comp. Ex. 1 precipitation Comp. Ex. 2 precipitation