Resin, resist composition and method for producing resist pattern

Abstract

Disclosed is a resin comprising a structural unit derived from a compound represented by formula (I) and a structural unit having an acid-labile group: ##STR00001## ##STR00002##
wherein R.sup.1 represents a hydrocarbon group which may have a substituent, R.sup.2 each independently represent an alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom, Ar represents an aromatic hydrocarbon group which may have a substituent, L.sup.1 represents a group represented by formula (L.sup.1-1), etc., L.sup.11, L.sup.13, L.sup.15 and L.sup.17 each independently represent an alkanediyl group, L.sup.12, L.sup.14, L.sup.16 and L.sup.18 each independently represent —O—, —CO—, —CO—O—, etc., * and ** are bonds, and ** represents a bond to an iodine atom.

Claims

1. A resin comprising a structural unit derived from a compound represented by formula (I) and a structural unit having an acid-labile group: ##STR00207## wherein, in formula (I), R.sup.1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms which may have a substituent or an aromatic hydrocarbon group having 6 to 24 carbon atoms which may have a substituent, and a methylene group included in the saturated hydrocarbon group may be substituted with an oxygen atom or a carbonyl group, R.sup.2 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom, Ar represents an aromatic hydrocarbon group having 6 to 24 carbon atoms which may have a substituent, and L.sup.1 represents a group represented by any one of formula (X.sup.1-1) to formula (X.sup.1-8): ##STR00208## ##STR00209## wherein, in formula (X.sup.1-5) to formula (X.sup.1-8), L.sup.11, L.sup.13, L.sup.15 and L.sup.17 each independently represent an alkanediyl group having 1 to 6 carbon atoms, L.sup.12, L.sup.14, L.sup.16, and L.sup.18 each independently represent —O—, —CO—, —CO—O—, —O—CO— or —O—CO—O—, and * and ** are bonds, and ** represents a bond to an iodine atom.

2. The resin according to claim 1, further comprising a structural unit which is decomposed upon exposure to radiation to generate an acid.

3. A resist composition comprising the resin according to claim 1 and an acid generator.

4. A resist composition comprising the resin according to claim 2.

5. The resist composition according to claim 3, further comprising a salt generating an acid having an acidity lower than that of an acid generated from the acid generator.

6. A method for producing a resist pattern, which comprises: (1) a step of applying the resist composition according to claim 3 on a substrate, (2) a step of drying the applied composition to form a composition layer, (3) a step of exposing the composition layer, (4) a step of heating the exposed composition layer, and (5) a step of developing the heated composition layer.

Description

EXAMPLES

(1) The present invention will be described more specifically by way of Examples. Percentages and parts expressing the contents or amounts used in the Examples are by mass unless otherwise specified.

(2) The weight-average molecular weight is a value determined by gel permeation chromatography under the following conditions.

(3) Equipment: HLC-8120 GPC type (manufactured by TOSOH CORPORATION)

(4) Column: TSKgel Multipore H.sub.XL−M×3+guardcolumn (manufactured by TOSOH CORPORATION)

(5) Eluent: tetrahydrofuran

(6) Flow rate: 1.0 mL/min

(7) Detector: RI detector

(8) Column temperature: 40° C.

(9) Injection amount: 100 μl

(10) Molecular weight standards: polystyrene standard (manufactured by TOSOH CORPORATION)

(11) Structures of compounds were confirmed by measuring a molecular ion peak using mass spectrometry (Liquid Chromatography: Model 1100, manufactured by Agilent Technologies, Inc., Mass Spectrometry: Model LC/MSD, manufactured by Agilent Technologies, Inc.). The value of this molecular ion peak in the following Examples is indicated by “MASS”.

Synthesis Example 1

Synthesis of Compound Represented by Formula (I-1)

(12) ##STR00189##

(13) 10 Parts of a compound represented by formula (I-1-a) and 50 parts of monochlorobenzene were mixed, followed by stirring at 23° C. for 30 minutes. To the mixed solution thus obtained, 8.4 parts of a compound represented by formula (I-1-b) was added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 15 parts of chloroform and 60 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain the filtrate containing a compound represented by formula (I-1-c). To the filtrate containing the compound represented by formula (I-1-c) thus obtained, 85 parts of monochlorobenzene and 4.0 parts of a compound represented by formula (I-1-d) were added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 20 parts of chloroform and 80 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain 7.4 parts of a compound represented by formula (I-1).

(14) MS (mass spectrometry): 469.1 [M+H].sup.+

Synthesis Example 2

Synthesis of Compound Represented by Formula (I-2)

(15) ##STR00190##

(16) 10 Parts of a compound represented by formula (I-1-a) and 50 parts of monochlorobenzene were mixed, followed by stirring at 23° C. for 30 minutes. To the mixed solution thus obtained, 9.1 parts of a compound represented by formula (I-2-b) was added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 5 parts of chloroform and 50 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain the filtrate containing a compound represented by formula (I-2-c). To the filtrate containing the compound represented by formula (I-2-c) thus obtained, 85 parts of monochlorobenzene and 4.0 parts of a compound represented by formula (I-1-d) were added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 10 parts of chloroform and 50 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain 7.8 parts of a compound represented by formula (I-2).

(17) MS (mass spectrometry): 405.0 [M+H].sup.+

Synthesis Example 3

Synthesis of Compound Represented by Formula (I-3)

(18) ##STR00191##

(19) 10 Parts of a compound represented by formula (I-1-a) and 50 parts of monochlorobenzene were mixed, followed by stirring at 23° C. for 30 minutes. To the mixed solution thus obtained, 15.8 parts of a compound represented by formula (I-3-b) was added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 50 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain the filtrate containing a compound represented by formula (I-3-c). To the filtrate containing a compound represented by formula (I-3-c) thus obtained, 85 parts of monochlorobenzene and 4.0 parts of a compound represented by formula (I-1-d) were added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 50 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain 10.8 parts of a compound represented by formula (I-3).

(20) MS (mass spectrometry): 627.1 [M+H].sup.+

Synthesis Example 4

Synthesis of Compound Represented by Formula (I-9)

(21) ##STR00192##

(22) 10.9 Parts of a compound represented by formula (1-9-a) and 50 parts of monochlorobenzene were mixed, followed by stirring at 23° C. for 30 minutes. To the mixed solution thus obtained, 8.4 parts of a compound represented by formula (I-1-b) was added, followed by stirring at 40° C. for 3 hours and further concentration. The reaction product thus obtained was mixed with 15 parts of chloroform and 60 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain the filtrate containing a compound represented by formula (I-9-c). To the filtrate containing a compound represented by formula (I-9-c) thus obtained, 85 parts of monochlorobenzene and 4.0 parts of a compound represented by formula (I-1-d) was added, followed by stirring at 40° C. for 3 hours and further filtration. The reaction product thus obtained was mixed with 20 parts of chloroform and 80 parts of n-heptane, followed by stirring at 23° C. for 30 minutes and further filtration to obtain 7.1 parts of a compound represented by formula (I-9).

(23) MS (mass spectrometry): 499.1 [M+H].sup.+

(24) Synthesis of Resin

(25) Compounds (monomers) used in the synthesis of a resin are shown below.

(26) ##STR00193## ##STR00194## ##STR00195##

(27) Hereinafter, these monomers are referred to as “monomer (a1-1-3)” according to the number of formula.

Example 1

Synthesis of Resin A1

(28) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1), a monomer (a3-1-1) and a monomer (I-1) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:31:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1):monomer (I-1)], and kethyl ethyl ketone was added in the amount of 1.5 mass times the total mass of all monomers to obtain a solution. To the solution thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1 mol % and 3 mol % based on the total molar number of all monomers, and then the mixture was heated at 75° C. for about 5 hours. The reaction mixture thus obtained was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and this resin was filtered. After performing a purification operation in which the resin thus obtained is added to a methanol/water mixed solvent, followed by repulping and further filtration, twice, a copolymer having a weight-average molecular weight of 7.8×10.sup.3 was obtained in a yield of 67%. This copolymer includes the following structural unit, and this is called a resin A1.

(29) ##STR00196##

Example 2

Synthesis of Resin A2

(30) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1) and a monomer (a3-1-1), monomer (II-2-A-1-1) and a monomer (I-1) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:7:31:3:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1):monomer (II-2-A-1-1):monomer (I-1)] and then, in the same manner as in resin A1, a copolymer having a weight-average molecular weight of 8.0×10.sup.3 was obtained in a yield of 57%. This copolymer includes the following structural unit, and this is called a resin A2.

(31) ##STR00197##

Example 3

Synthesis of Resin A3

(32) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1), a monomer (a3-1-1) and a monomer (I-2) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:31:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1): monomer (I-2)], and kethyl ethyl ketone was added in the amount of 1.5 mass times the total mass of all monomers to obtain a solution. To the solution thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1 mol % and 3 mol % based on the total molar number of all monomers, and then the mixture was heated at 75° C. for about 5 hours. The reaction mixture thus obtained was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and this resin was filtered. After performing a purification operation in which the resin thus obtained is added to a methanol/water mixed solvent, followed by repulping and further filtration, twice, a copolymer having a weight-average molecular weight of 7.6×10.sup.3 was obtained in a yield of 65%. This copolymer includes the following structural unit, and this is called a resin A3.

(33) ##STR00198##

Example 4

Synthesis of Resin A4

(34) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1), a monomer (a3-1-1) and a monomer (1-3) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:31:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1): monomer (1-3)], and kethyl ethyl ketone was added in the amount of 1.5 mass times the total mass of all monomers to obtain a solution. To the solution thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1 mol % and 3 mol % based on the total molar number of all monomers, and then the mixture was heated at 75° C. for about 5 hours. The reaction mixture thus obtained was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and this resin was filtered. After performing a purification operation in which the resin thus obtained is added to a methanol/water mixed solvent, followed by repulping and further filtration, twice, a copolymer having a weight-average molecular weight of 7.2×10.sup.3 was obtained in a yield of 60%. This copolymer includes the following structural unit, and this is called a resin A4.

(35) ##STR00199##

Example 5

Synthesis of Resin A5

(36) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1), a monomer (a3-1-1) and a monomer (I-9) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:31:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1):monomer (I-9)], and kethyl ethyl ketone was added in the amount of 1.5 mass times the total mass of all monomers to obtain a solution. To the solution thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1 mol % and 3 mol % based on the total molar number of all monomers, and then the mixture was heated at 75° C. for about 5 hours. The reaction mixture thus obtained was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and this resin was filtered. After performing a purification operation in which the resin thus obtained is added to a methanol/water mixed solvent, followed by repulping and further filtration, twice, a copolymer having a weight-average molecular weight of 7.9×10.sup.3 was obtained in a yield of 64%. This copolymer includes the following structural unit, and this is called a resin A5.

(37) ##STR00200##

Synthesis Example 5

Synthesis of Resin AX1

(38) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1), a monomer (a3-1-1) and a monomer (IX-1) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:31:3 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1):monomer (IX-1)], and kethyl ethyl ketone was added in the amount of 1.5 mass times the total mass of all monomers to obtain a solution. To the solution thus obtained, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) as initiators were added in the amounts of 1 mol % and 3 mol % based on the total molar number of all monomers, and then the mixture was heated at 75° C. for about 5 hours. The reaction mixture thus obtained was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and this resin was filtered. After performing a purification operation in which the resin thus obtained is added to a methanol/water mixed solvent, followed by repulping and further filtration, twice, a copolymer having a weight-average molecular weight of 8.6×10.sup.3 was obtained in a yield of 60%. This copolymer includes the following structural unit, and this is called a resin AX1.

(39) ##STR00201##

Synthesis Example 6

Synthesis of Resin AX2

(40) Using a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), a monomer (a3-2-1) and a monomer (a3-1-1) as monomers, and these monomers were mixed in a molar ratio of 28:25:3:10:34 [monomer (a1-1-3):monomer (a1-2-9):monomer (a2-1-3):monomer (a3-2-1):monomer (a3-1-1)] and then, in the same manner as in resin AX1, a copolymer having a weight-average molecular weight of 7.5×10.sup.3 was obtained in a yield of 65%. This copolymer includes the following structural unit, and this is called a resin AX2.

(41) ##STR00202##
<Preparation of Resist Composition>

(42) The following respective components were mixed in each amount (parts by mass) shown in Table 1 and dissolved in a solvent, and then the mixture was filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare resist compositions.

(43) TABLE-US-00001 TABLE 1 Resist Acid composition Resin generator Quencher PB/PEB Composition 1 A1 = B1-25 = C1 = 100° C./110° C. 10 parts 3.0 parts 0.3 part Composition 2 A1 = B1-25 = D1 = 100° C./110° C. 10 parts 3.0 parts 0.3 part Composition 3 A1 = B1-25 = D2 = 100° C./110° C. 10 parts 3.0 parts 0.3 parts Composition 4 A2 = B1-25 = C1 = 100° C./110° C. 10 parts 1.0 part 0.3 part Composition 5 A2 = — C1 = 100° C./110° C. 10 parts 0.3 part Composition 6 A3 = B1-25 = C1 = 100° C./110° C. 10 parts 3.0 parts 0.3 part Composition 7 A4 = B1-25 = C1 = 100° C./110° C. 10 parts 3.0 parts 0.3 part Composition 8 A5 = B1-25 = C1 = 100° C./110° C. 10 parts 3.0 parts 0.3 part Comparative AX1 = B1-25 = C1 = 100° C./110° C. composition 1 10 parts 3.0 parts 0.3 part Comparative AX2 = B1-25 = D2 = 100° C./110° C. composition 2 10 parts 3.0 parts 0.3 part
<Resin (A)>

(44) A1 to A5, AX1, AX2: Resin A1 to Resin A5, Resin AX1, Resin AX2

(45) <Acid Generator (B)>

(46) B1-25: Salt represented by formula (B1-25); synthesized by the method mentioned in JP 2011-126869 A

(47) ##STR00203##
<Quencher (C)>

(48) C1: synthesized by the method mentioned in JP 2011-39502 A

(49) ##STR00204##

(50) D1: (manufactured by Tokyo Chemical Industry Co., Ltd.)

(51) ##STR00205##

(52) D2: synthesized in accordance with Examples of JP 2015-180928 A

(53) ##STR00206##
<Solvent (E)>

(54) TABLE-US-00002 Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-Butyrolactone  5 parts
(Evaluation of Exposure of Resist Composition with Electron Beam)

(55) Each 6 inch-diameter silicon wafer was treated with hexamethyldisilazane on a direct hot plate at 90° C. for 60 seconds. A resist composition was spin-coated on the silicon wafer so that the thickness of the composition later became 0.04 μm. Subsequently, the coated silicon wafer was prebaked on the direct hot plate at the temperature shown in the column “PB” of Table 1 for 60 seconds. Using an electron-beam direct-write system (HL-800D 50 keV, manufactured by Hitachi, Ltd.), line-and-space patterns were directly written on the composition layer formed on the wafer while changing the exposure dose stepwise.

(56) After the exposure, post-exposure baking was performed on the hot plate at the temperature shown in the column “PEB” of Table 1 for 60 seconds, followed by paddle development with an aqueous 2.38% by mass tetramethylammonium hydroxide solution for 60 seconds to obtain a resist pattern.

(57) The resist pattern (line-and-space pattern) thus obtained was observed by a scanning electron microscope and effective sensitivity was defined as the exposure dose at which the resist pattern with 60 nm-1:1 line and space patterns was obtained.

(58) Evaluation of Line Edge Roughness (LER): Line edge roughness was determined by measuring a roughness width of the irregularity in wall surface of the resist pattern produced by the effective sensitivity using a scanning electron microscope. The results are shown in Table 2.

(59) TABLE-US-00003 TABLE 2 Resist composition LER Example 6 Composition 1 3.88 Example 7 Composition 2 3.93 Example 8 Composition 3 3.95 Example 9 Composition 4 4.00 Example 10 Composition 5 4.12 Example 11 Composition 6 3.78 Example 12 Composition 7 3.72 Example 13 Composition 8 3.84 Comparative Comparative 4.74 Example 1 composition 1 Comparative Comparative 4.43 Example 2 composition 2

INDUSTRIAL APPLICABILITY

(60) A resin and a resist composition including the same of the present invention exhibit satisfactory line edge roughness and are useful for fine processing of semiconductors.