RESIST UNDERLAYER FILM-FORMING COMPOSITION

Abstract

A composition for forming a resist underlayer film containing a solvent and polymer comprising a unit structure (A) represented by formula (1) and/or formula (2). The composition is capable of forming a hydrophobic underlayer film that has a high contact angle with pure water and exhibits high adhesion to an upper layer film, thereby being not susceptible to separation therefrom, while meeting the requirement of good coatability, the composition being also capable of exhibiting other good characteristics such as sufficient resistance to a chemical agent that is used for resist underlayer films.

Claims

1. A resist underlayer film-forming composition comprising a solvent and a polymer comprising a unit structure (A) represented by the following formula (1) and/or formula (2): ##STR00030## wherein Ar.sup.1 and Ar.sup.2 each represent a benzene ring or naphthalene ring, Ar.sup.1 and Ar.sup.2 may be bonded via a single bond; Ar.sup.3 represents an aromatic compound having 6 to 60 carbon atoms and optionally containing a nitrogen atom; R.sup.1 and R.sup.2 are groups substituting hydrogen atoms on the rings of Ar.sup.1 and Ar.sup.2, respectively, and are selected from the group consisting of a halogen atom, a nitro group, an amino group, a cyano group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond; R.sup.3 and R.sup.8 are selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond, and the aryl group may be substituted with an alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group; R.sup.4 and R.sup.6 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond; R.sup.5 and R.sup.7 are selected from the group consisting of a hydrogen atom, a trifluoromethyl group, an aryl group having 6 to 40 carbon atoms, and a heterocyclic group, the aryl group and the heterocyclic group may be substituted with a halogen atom, a nitro group, an amino group, a cyano group, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 40 carbon atoms, and the alkyl group, the alkenyl group, the alkynyl group and the aryl group may contain an ether bond, a ketone bond, or an ester bond; R.sup.4 and R.sup.5, and R.sup.6 and R.sup.7 may be combined with a carbon atom to which they are bonded to form a ring; n1 and n2 are each an integer of from 0 to 3; n3 is an integer of 1 or more but not more than a number of substituent with which Ar.sup.3 can be substituted; and n4 is 0 or 1, but when n4 is 0, R.sup.8 is bonded to a nitrogen atom contained in Ar.sup.3.

2. The resist underlayer film-forming composition according to claim 1, wherein Ar.sup.1 and Ar.sup.2 in formula (1) are benzene rings.

3. The resist underlayer film-forming composition according to claim 1, wherein Ar.sup.3 in formula (2) is an optionally substituted benzene, naphthalene, diphenylfluorene, or phenylindole ring.

4. The resist underlayer film-forming composition according to claim 1, wherein in formula (1) or (2), R.sup.4 and R.sup.6 are aryl groups having 6 to 40 carbon atoms, and R.sup.5 and R.sup.7 are hydrogen atoms.

5. The resist underlayer film-forming composition according to claim 1, wherein in formula (1) or (2), R.sup.4 and R.sup.6 are aromatic hydrocarbon groups having 6 to 16 carbon atoms.

6. The resist underlayer film-forming composition according to claim 1 further comprising a crosslinking agent.

7. The resist underlayer film-forming composition according to claim 1 further comprising an acid and/or an acid generator.

8. The resist underlayer film-forming composition according to claim 1, wherein the solvent has a boiling point of 160° C. or higher.

9. A resist underlayer film, which is a baked product of a coating film comprising the resist underlayer film-forming composition according claim 1.

10. A method for producing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to claim 1; forming a resist film on the formed resist underlayer film; forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development; etching and patterning the resist underlayer film through the formed resist pattern; and processing the semiconductor substrate through the patterned resist underlayer film.

11. A method for producing a semiconductor device, comprising the steps of: forming a resist underlayer film on a semiconductor substrate using the resist underlayer film-forming composition according to claim 1; forming a hard mask on the formed resist underlayer film; forming a resist film on the formed hard mask; forming a resist pattern by irradiating the formed resist film with a light or electron beam followed by development; etching the hard mask through the formed resist pattern; etching the resist underlayer film through the etched hard mask; and removing the hard mask.

12. The method for producing a semiconductor device according to claim 11, further comprising the steps of: forming a vapor-deposited film (spacer) on the underlayer film from which the hard mask has been removed; processing the formed vapor-deposited film (spacer) by etching; removing the underlayer film; and processing the semiconductor substrate with the spacer.

13. The method for producing a semiconductor device according to claim 10, wherein the semiconductor substrate is a stepped substrate.

Description

EXAMPLES

[0184] The present invention is described in more detail below with reference to examples and others, but the present invention is not limited in any way by the following examples.

[0185] The apparatus and others used to measure the weight average molecular weight of the compounds obtained in the synthesis examples are described below.

[0186] Apparatus: HLC-8320 GPC manufactured by Tosoh Corporation

[0187] GPC column: TSKgel Super-Multipore HZ-N (two columns)

[0188] Column temperature: 40° C.

[0189] Flow rate: 0.35 mL/min

[0190] Eluent: THF

[0191] Standard sample: polystyrene

Synthesis Example 1

[0192] 35.00 g of diphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 21.97 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.60 g of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as MSA), and 230.25 g of propylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA) were placed in a flask. The mixture was then heated to 115° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-1). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,100.

##STR00015##

Synthesis Example 2

[0193] 35.00 g of carbazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 32.72 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 2.01 g of MSA, and 162.71 g of PGMEA were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-2). The weight average molecular weight Mw measured by GPC measured in terms of polystyrene by GPC was about 2,600.

##STR00016##

Synthesis Example 3

[0194] 50.00 g of 2-phenylindole (manufactured by Tokyo Chemical Industry Co., Ltd.), 40.41 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 4.97 g of MSA, and 143.07 g of PGMEA were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for about 7 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-3). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 1,700.

##STR00017##

Synthesis Example 4

[0195] 45.00 g of 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.), 29.79 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 5.40 g of MSA, and 187.11 g of PGMEA were placed in a flask. The mixture was then heated to reflux under nitrogen and allowed to react for about 1.5 hours. After the termination of the reaction, the product was diluted with propylene glycol monomethyl ether (hereafter referred to as PGME), precipitated with water/methanol, and dried to obtain a resin (1-4). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,600.

##STR00018##

Synthesis Example 5

[0196] 60.00 g of 9,9-bis (4-hydroxyphenyl) fluorene (manufactured by Tokyo Chemical Industry Co., Ltd.), 18.17 g of benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 3.29 g of MSA, and 99.56 g of PGMEA were placed in a flask. The mixture was then heated to reflux under nitrogen and allowed to react for about 4 hours. After the termination of the reaction, the product was diluted with PGMEA, precipitated with water/methanol, and dried to obtain a resin (1-5). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,100.

##STR00019##

Synthesis Example 6

[0197] 70.00 g of 2,2-biphenol (manufactured by Tokyo Chemical Industry Co., Ltd.), 29.36 g of 1-naphthaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), 43.28 g of 1-pyrenecarboxylaldehyde, 10.83 g of MSA, and 54.81 g of PGME were placed in a flask. The mixture was then heated to 120° C. under nitrogen, and allowed to react for 24 hours. After the termination of the reaction, the mixture was precipitated with methanol and dried to obtain a resin (1-6). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,000.

##STR00020##

Synthesis Example 7

[0198] 10.00 g of the resin obtained in Synthesis Example 1, 6.97 g of propargylic bromide (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as PBr), 2.17 g of tetrabutylammonium iodide (hereinafter referred to as TB AI), 21.53 g of tetrahydrofuran (hereinafter referred to as THF), and 7.18 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with methyl isobutyl ketone (hereinafter referred to as MIBK) and water, and the organic layer was concentrated, redissolved in

[0199] PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-7). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,100.

##STR00021##

Synthesis Example 8

[0200] 10.00 g of the resin obtained in Synthesis Example 2, 6.89 g of PBr, 3.21 g of TBAI, 22.61 g of THF, and 7.54 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 18 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-8). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 3,000.

##STR00022##

Synthesis Example 9

[0201] 15.00 g of the resin obtained in Synthesis Example 3, 10.52 g of PBr, 4.90 g of TBAI, 34.21 g of THF, and 11.40 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with methanol, and dried to obtain a resin (1-9). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 1,900.

##STR00023##

Synthesis Example 10

[0202] 15.00 g of the resin obtained in Synthesis Example 4, 12.57 g of PBr, 5.85 g of tetrabutylammonium bromide (hereinafter referred to as TBAB), 37.60 g of THF, and 12.53 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 16 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-10). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,900.

##STR00024##

Synthesis Example 11

[0203] 15.00 g of the resin obtained in Synthesis Example 5, 13.57 g of PBr, 6.32 g of TBAB, 39.25 g of THF, and 13.08 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 16 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-11). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 4,600.

##STR00025##

Synthesis Example 12

[0204] 10.00 g of the resin obtained in Synthesis Example 6, 12.78 g of PBr, 5.86 g of TBAB, 21.48 g of THF, and 7.16 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with MIBK and water, and the organic layer was concentrated, redissolved in PGMEA, reprecipitated with water/methanol, and dried to obtain a resin (1-12).

[0205] The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,300.

##STR00026##

Synthesis Example 13

[0206] 10.00 g of the resin obtained in Synthesis Example 1, 10.99 g of α-chloro-p-xylene (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as CMX), 5.77 g of TBAI, 16.06 g of THF, and 10.71 g of a 25% aqueous sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and cyclohexanone (hereinafter referred to as CYH), and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-13). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 5,500.

##STR00027##

[0207] 10.00 g of the resin obtained in Synthesis Example 2, 9.91 g of benzyl bromide (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter referred to as BBr), 3.21 g of TBAI, 26.01 g of THF, and 8.67 g of a 25% aqueous sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 18 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and CYH, and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-14). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 2,800.

##STR00028##

Synthesis Example 15

[0208] 10.00 g of the resin obtained in Synthesis Example 6, 15.55 g of BBr, 4.40 g of TBAB, 22.46 g of THF, and 7.49 g of a 25% sodium hydroxide solution were placed in a flask. The mixture was then heated to 55° C. under nitrogen, and allowed to react for about 15 hours. After the termination of the reaction, the liquid separation operation was repeated with water and a mixed solvent of MIBK and CYH, and the organic layer was concentrated, redissolved in CYH, reprecipitated with methanol, and dried to obtain a resin (1-15). The weight average molecular weight Mw measured in terms of polystyrene by GPC was about 6,000.

##STR00029##

Example 1

[0209] The resin obtained in Synthesis Example 7 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.48% compound solution. To 2.43 g of this resin solution, 0.12 g of PL-LI (manufactured by Midori Kagaku Co., Ltd.), 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant (manufactured by DIC Corporation, Megafac R-40), 8.07 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 2

[0210] The resin obtained in Synthesis Example 8 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.63% compound solution. To 2.54 g of this resin solution, 0.12 g of 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.96 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 3

[0211] The resin obtained in Synthesis Example 9 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 22.47% compound solution. To 2.53 g of this resin solution, 0.11 g of PL-LI, 0.85 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 10 0.06 g of PGMEA containing 1% by mass of a surfactant, 11.49 g of PGMEA, and 4.95 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 4

[0212] The resin obtained in Synthesis Example 10 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.21% compound solution. To 3.60 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 13.91 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 5

[0213] The resin obtained in Synthesis Example 11 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 21.25% compound solution. To 3.25 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 14.26 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 6

[0214] The resin obtained in Synthesis Example 12 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.44% compound solution. To 2.44 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGM containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 8.07 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 7

[0215] The resin obtained in Synthesis Example 13 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.77% compound solution. To 2.40 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 3.53 of PGME, and 6.72 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 8

[0216] The resin obtained in Synthesis Example 14 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 21.63% compound solution. To 2.19 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 2.53 of PGME, and 6.92 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Example 9

[0217] The resin obtained in Synthesis Example 15 was dissolved in CYH, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.56% compound solution. To 2.42 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 2.83 g of PGMEA, 2.53 of PGME, and 6.69 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 1

[0218] The resin obtained in Synthesis Example 1 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.73% compound solution. To 2.53 g of this resin solution, 0.12 g of 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.98 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 2

[0219] The resin obtained in Synthesis Example 2 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 17.08% compound solution. To 2.77 g of this resin solution, 0.12 g of PL-LI, 0.36 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 7.73 g of PGMEA, and 3.97 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 3

[0220] The resin obtained in Synthesis Example 3 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 20.20% compound solution. To 2.41 g of this resin solution, 0.10 g of PL-LI, 0.73 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.05 g of PGMEA containing 1% by mass of a surfactant, 0.91 g of PGMEA, 2.16 g of PGME, and 8.64 g of CYH were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 4

[0221] The resin obtained in Synthesis Example 4 was dissolved in PGME, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 18.06% compound solution. To 3.83 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 7.17 g of PGMEA, and 13.24 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore size of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 5

[0222] The resin obtained in Synthesis Example 5 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 19.44% compound solution. To 3.56 g of this resin solution, 0.17 g of PL-LI, 0.52 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.07 g of PGMEA containing 1% by mass of a surfactant, 13.95 g of PGMEA, and 6.73 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

Comparative Example 6

[0223] The resin obtained in Synthesis Example 6 was dissolved in PGMEA, and subjected to ion exchange treatment with cation and anion exchange resins for 4 hours to obtain a 29.80% compound solution. To 2.78 g of this resin solution, 0.21 g of PL-LI, 0.62 g of PGME containing 2% by mass of pyridinium p-toluenesulfonic acid, 0.08 g of PGMEA containing 1% by mass of a surfactant, 7.73 g of PGMEA, and 3.58 g of PGME were added and dissolved. The resulting solution was filtered through a polytetrafluoroethylene microfilter having a pore diameter of 0.1 μm to prepare a solution of a resist underlayer film-forming composition.

[0224] (Contact Angle Measurement)

[0225] Each of the polymer solutions used in Comparative Examples 1-6 and 1-9 was applied to a silicon wafer using a spin coater, and baked on a hot plate at 160° C. for 60 seconds to form a polymer film. Thereafter, the contact angle of the polymer to pure water was measured using a contact angle meter manufactured by Kyowa Interface Science Co., Ltd. The contact angle of the polymer used in each of the Examples was compared with that of the polymer used in the corresponding Comparative Example, respectively. The cases in which the contact angle of the polymer used in the Example was higher than that in the corresponding Comparative Example were indicated as “○”.

TABLE-US-00001 TABLE 1 Baking Pure water Sample Polymer temperature contact angle Comparative Synthesis 160° C. x Example 1 Example 1 Comparative Synthesis 160° C. x Example 2 Example 2 Comparative Synthesis 160° C. x Example 3 Example 3 Comparative Synthesis 160° C. x Example 4 Example 4 Comparative Synthesis 160° C. x Example 5 Example 5 Comparative Synthesis 160° C. x Example 6 Example 6 Example 1 Synthesis 160° C. ∘ Example 7 Example 2 Synthesis 160° C. ∘ Example 8 Example 3 Synthesis 160° C. ∘ Example 9 Example 4 Synthesis 160° C. ∘ Example 10 Example 5 Synthesis 160° C. ∘ Example 11 Example 6 Synthesis 160° C. ∘ Example 12 Example 7 Synthesis 160° C. ∘ Example 13 Example 8 Synthesis 160° C. ∘ Example 14 Example 9 Synthesis 160° C. ∘ Example 15

[0226] Comparing Comparative Example 1 with Example 1 and Example 7, Comparative Example 2 with Example 2 and Example 8, Comparative Example 3 with Example 3, Comparative Example 4 with Example 4, Comparative Example 5 with Example 5, and Comparative Example 6 with Example 6 and Example 9 revealed that the polymers used in Examples showed a higher contact angle than those used in Comparative Examples.

[0227] (Elution Test in Resist Solvent)

[0228] Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to a silicon wafer, respectively, using a spin coater, and baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film (film thickness: 65 nm). These resist underlayer films were immersed in a mixed solvent of PGME/PGMEA in a ratio of 7/3, which is a general-purpose thinner. The resist underlayer film was insoluble. And it was confirmed that the film had a sufficient curability.

TABLE-US-00002 TABLE 2 Baking Sample Polymer temperature Curability Comparative Synthesis 240 C. ∘ Example 1 Example 1 Comparative Synthesis 240 C. ∘ Example 2 Example 2 Comparative Synthesis 240 C. ∘ Example 3 Example 3 Comparative Synthesis 240 C. ∘ Example 4 Example 4 Comparative Synthesis 240 C. ∘ Example 5 Example 5 Comparative Synthesis 240 C. ∘ Example 6 Example 6 Example 1 Synthesis 240 C. ∘ Example 7 Example 2 Synthesis 240 C. ∘ Example 8 Example 3 Synthesis 240 C. ∘ Example 9 Example 4 Synthesis 240 C. ∘ Example 10 Example 5 Synthesis 240 C. ∘ Example 11 Example 6 Synthesis 240 C. ∘ Example 12 Comparative Synthesis 350 C. ∘ Example 1 Example 1 Comparative Synthesis 350 C. ∘ Example 2 Example 2 Comparative Synthesis 350 C. ∘ Example 6 Example 6 Example 7 Synthesis 350 C. ∘ Example 13 Example 8 Synthesis 350 C. ∘ Example 14 Example 9 Synthesis 350 C. ∘ Example 15

[0229] (Application Property Test)

[0230] Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to a silicon wafer, respectively, using a spin coater, and baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film. Further thereon, a coating type silicon solution was applied and baked at 215° C. for 60 seconds to form a silicon film. Thereafter, the thickness of the film was measured. Then, a value was calculated according to “[Variation in film thickness (maximum film thickness—minimum film thickness)]/[Average film thickness]×100”. When this value is low, the application property can be judged to be good. The cases in which the application property of the Example is better than that of the corresponding Comparative Example were judged as

TABLE-US-00003 TABLE 3 Baking Application Sample Polymer temperature property Comparative Synthesis 240 C. x Example 1 Example 1 Comparative Synthesis 240 C. x Example 2 Example 2 Comparative Synthesis 240 C. x Example 3 Example 3 Comparative Synthesis 240 C. x Example 4 Example 4 Comparative Synthesis 240 C. x Example 5 Example 5 Comparative Synthesis 240 C. x Example 6 Example 6 Example 1 Synthesis 240 C. ∘ Example 7 Example 2 Synthesis 240 C. ∘ Example 8 Example 3 Synthesis 240 C. ∘ Example 9 Example 4 Synthesis 240 C. ∘ Example 10 Example 5 Synthesis 240 C. ∘ Example 11 Example 6 Synthesis 240 C. ∘ Example 12 Comparative Synthesis 350 C. x Example 1 Example 1 Comparative Synthesis 350 C. x Example 2 Example 2 Comparative Synthesis 350 C. x Example 6 Example 6 Example 7 Synthesis 350 C. ∘ Example 13 Example 8 Synthesis 350 C. ∘ Example 14 Example 9 Synthesis 350 C. ∘ Example 15

[0231] Comparing Comparative Example 1 with Example 1 and Example 7, Comparative Example 2 with Example 2 and Example 8, Comparative Example 3 with Example 3, Comparative Example 4 with Example 4, Comparative Example 5 with Example 5, Comparative Example 6 with Example 6 and Example 9 revealed that Examples exhibited better application properties than Comparative Examples. This is due to the hydrophobic nature of the polymer, which improved the application property.

[0232] (Chemical Solution Resistance Test)

[0233] Each of the solutions of the resist underlayer film-forming compositions prepared in Comparative Example 1-6 and Example 1-9 was applied to SiON, respectively, using a spin coater. The coating was baked on a hot plate at 240° C. for 60 seconds or 350° C. for 60 seconds to form a resist underlayer film (film thickness: 65 nm thick). Thereon were formed a silicon hard mask layer (film thickness: 20 nm) and a resist layer (AR2772JN-14, manufactured by JSR Corporation, film thickness: 120 nm). The product was exposed at a wavelength of 193 nm using a mask followed by development to obtain a resist pattern. Then, the resist pattern was dry etched using fluorine-based gas and oxygen-based gas using an etching apparatus manufactured by Lam Research Co., Ltd., and the resulting resist pattern was transferred to the resist underlayer film. By the confirmation with CG-4100 manufactured by Hitachi Technology Co., Ltd., the pattern shape was confirmed to have provided a 50 nm line pattern.

[0234] The pattern wafer obtained here was cut and immersed in SARC-410 (manufactured by Nihon Entegris G.K.) heated to 30° C. After immersion, the wafer was taken out, rinsed with water, and dried. The dried wafer was observed with a scanning electron microscope (Regulus 8240) to check whether the pattern shape formed by the resist underlayer film was not deteriorated or whether the pattern was not collapsed. When the pattern shape is not deteriorated and is not suffered from collapse, its resistance to the chemical solution is high. The cases in which the polymer caused neither pattern shape deterioration nor pattern collapse even after immersion in the chemical solution for a longer period of time than the polymer of a similar structure in Comparative Example were judged as “○”.

TABLE-US-00004 TABLE 4 Collapse Pattern shape of pattern Chemical Baking after chemical after chemical solution Sample temperature Peeling solution treatment solution treatment resistance Comparative 240° C. No peeling Curved Collapsed x Example 1 Comparative 240° C. Peeled — — x Example 2 Comparative 240° C. Peeled Curved Collapsed x Example 3 Comparative 240° C. Peeled — — x Example 4 Comparative 240° C. Peeled — — x Example 5 Comparative 240° C. No peeling Curved Collapsed x Example 6 Example 1 240° C. No peeling Vertical No collapse ∘ Example 2 240° C. No peeling Vertical No collapse ∘ Example 3 240° C. No peeling Vertical No collapse ∘ Example 4 240° C. No peeling Vertical No collapse ∘ Example 5 240° C. No peeling Vertical No collapse ∘ Example 6 240° C. No peeling Vertical No collapse ∘ Comparative 350° C. No peeling Curved Collapsed x Example 1 Comparative 350° C. No peeling Curved Collapsed x Example 2 Comparative 350° C. No peeling Curved Collapsed x Example 6 Example 7 350° C. No peeling Vertical No collapse ∘ Example 8 350° C. No peeling Vertical No collapse ∘ Example 9 350° C. No peeling Vertical No collapse ∘

[0235] In the cases of baking at 240° C., as seen in comparisons between Comparative Example 1 and Example 1, Comparative Example 2 and Example 2, Comparative Example 3 and Example 3, Comparative Example 4 and Example 4, Comparative Example 5 and Example 5, and Comparative Example 6 and Example 6, modification of amino and hydroxyl groups made it possible to improve the chemical solution resistance to alkaline chemical solutions. Similarly, the chemical solution resistance was improved in the cases of high-temperature baking at 350° C. Therefore, they are the materials that can be applied to the processes using chemical solutions.

INDUSTRIAL APPLICABILITY

[0236] The present invention provides a novel resist underlayer film-forming composition that can meet such requirements: providing a hydrophobic underlayer film that exhibits a high contact angle with pure water and a high adhesion to the upper layer film, and robust to peeling off, as well as having a good application property, while also exhibiting other good properties such as sufficient resistance to the chemical solutions used for the resist underlayer film.