Resist base material, resist composition and method for forming resist pattern

Abstract

The present invention provides a resist base material containing a compound having a specific structure and/or a resin derived from the compound as a monomer.

Claims

1. A resist composition comprising: a solvent; and a resist base material comprising a compound represented by the following formula (1) and/or a resin derived from the compound as a monomer ##STR00052## wherein R.sup.1 is a 2n-valent group of 1 to 30 carbon atoms; R.sup.2 to R.sup.5 are each independently a linear, branched, or cyclic alkyl group of 1 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, an alkoxy group of 1 to 30 carbon atoms, a halogen atom, a thiol group, or a hydroxyl group, wherein at least one selected from R.sup.1 to R.sup.5 is a group containing an iodine atom, and at least one of R.sup.4 and/or at least one of R.sup.5 is selected from a hydroxyl group and a thiol group; m.sup.2 and m.sup.3 are each independently an integer of 0 to 8; m.sup.4 and m.sup.5 are each independently an integer of 0 to 9, wherein m.sup.4 and m.sup.5 are not 0 at the same time; n is an integer of 1 to 4; and p.sup.2 to p.sup.5 are each independently an integer of 0 to 2.

2. The resist composition according to claim 1, wherein at least one of R.sup.2 and/or at least one of R.sup.3 is selected from a hydroxyl group and a thiol group.

3. The resist composition according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (1a): ##STR00053## wherein R.sup.1 to R.sup.5 and n are as defined in claim 1; m.sup.2 and m.sup.3 are each independently an integer of 0 to 4; and m.sup.4 and m.sup.5 are each independently an integer of 0 to 5, wherein m.sup.4 and m.sup.5 are not 0 at the same time.

4. The resist composition according to claim 3, wherein the compound represented by the formula (1a) is a compound represented by the following formula (1b): ##STR00054## wherein R.sup.1 is a 2n-valent group of 1 to 30 carbon atoms; R.sup.6 and R.sup.7 are each independently a linear, branched, or cyclic alkyl group of 1 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, an alkoxy group of 1 to 30 carbon atoms, a halogen atom, or a thiol group, wherein at least one selected from R.sup.1, R.sup.6, and R.sup.7 is a group containing an iodine atom; and m.sup.6 and m.sup.7 are each independently an integer of 0 to 7.

5. The resist composition according to claim 4, wherein the compound represented by the formula (1b) is a compound represented by the following formula (1c): ##STR00055## wherein R.sup.8 are each independently a hydrogen atom, a cyano group, a nitro group, a heterocyclic group, a halogen atom, a linear aliphatic hydrocarbon group of 1 to 20 carbon atoms, a branched aliphatic hydrocarbon group of 3 to 20 carbon atoms, a cyclic aliphatic hydrocarbon group of 3 to 20 carbon atoms, an aryl group of 6 to 20 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, an alkoxy group of 1 to 30 carbon atoms, a thiol group, or a hydroxyl group, wherein at least one of R.sup.8 is a group containing an iodine atom.

6. The resist composition according to claim 5, wherein the compound represented by the formula (1c) is a compound represented by the following formula (1d): ##STR00056## wherein R.sup.9 are each independently a cyano group, a nitro group, a heterocyclic group, a halogen atom, a linear aliphatic hydrocarbon group of 1 to 20 carbon atoms, a branched aliphatic hydrocarbon group of 3 to 20 carbon atoms, a cyclic aliphatic hydrocarbon group of 3 to 20 carbon atoms, an aryl group of 6 to 20 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, an alkoxy group of 1 to 30 carbon atoms, a thiol group, or a hydroxyl group; and m.sup.9 is an integer of 0 to 4.

7. The resist composition according to claim 1, wherein the resin is a resin obtained by reacting the compound represented by the formula (1) with a compound having crosslinking reactivity.

8. The resist composition according to claim 7, wherein the compound having crosslinking reactivity is an aldehyde, a ketone, a carboxylic acid, a carboxylic acid halide, a halogen-containing compound, an amino compound, an imino compound, an isocyanate, or an unsaturated hydrocarbon group-containing compound.

9. The resist composition according to claim 1, wherein the resin has a structure represented by the following formula (2): ##STR00057## wherein R.sup.1 is a 2n-valent group of 1 to 30 carbon atoms; R.sup.2 to R.sup.5 are each independently a linear, branched, or cyclic alkyl group of 1 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, an alkoxy group of 1 to 30 carbon atoms, a halogen atom, a thiol group, or a hydroxyl group, wherein at least one selected from R.sup.1 to R.sup.5 is a group containing an iodine atom, and at least one of R.sup.4 and/or at least one of R.sup.5 is selected from a hydroxyl group and a thiol group; L is a linear or branched alkylene group of 1 to 20 carbon atoms or a single bond; m.sup.2 and m.sup.3 are each independently an integer of 0 to 8; m.sup.4 and m.sup.5 are each independently an integer of 0 to 9, wherein m.sup.4 and m.sup.5 are not 0 at the same time; n is an integer of 1 to 4; and p.sup.2 to p.sup.5 are each independently an integer of 0 to 2.

10. The resist composition according to claim 1, further comprising an acid generating agent.

11. The resist composition according to claim 10, further comprising an acid crosslinking agent.

12. A method for forming a resist pattern, comprising the steps of: coating a substrate with the resist composition according to claim 10, thereby forming a resist film; exposing the formed resist film to radiation; and developing the exposed resist film to form the resist pattern.

13. The resist composition according to claim 1, further comprising an acid crosslinking agent.

14. A method for forming a resist pattern, comprising the steps of: coating a substrate with the resist composition according to claim 1, thereby forming a resist film; exposing the formed resist film to radiation; and developing the exposed resist film to form the resist pattern.

Description

EXAMPLES

(1) The present embodiment will be more specifically described with reference to synthesis examples and examples below. However, the present invention is not limited to these examples by any means.

(2) [Measurement Method]

(3) (1) Structure of Compound

(4) The structure of a compound was confirmed by conducting .sup.1H-NMR measurement under the following conditions using Advance 60011 spectrometer manufactured by Bruker Corporation.

(5) Frequency: 400 MHz

(6) Solvent: d6-DMSO

(7) Internal standard: TMS

(8) Measurement temperature: 23 C.

(9) (2) Molecular Weight

(10) The molecular weight of a compound was measured using Acquity UPLC/MALDI-Synapt HDMS manufactured by Water Corporation according to LC-MS analysis.

(11) Also, gel permeation chromatography (GPC) analysis was conducted under the following conditions to determine a polystyrene based weight average molecular weight (Mw), a number average molecular weight (Mn), and molecular weight distribution (Mw/Mn).

(12) Apparatus: Shodex GPC-101 model (manufactured by Showa Denko K.K.)

(13) Column: KF-80M3

(14) Eluent: 1 mL/min THF

(15) Temperature: 40 C.

(16) (3) Thermal Reduction Temperature

(17) EXSTAR 6000 DSC apparatus manufactured by SII NanoTechnology Inc. was used. About 5 mg of a sample was placed in an unsealed container made of aluminum, and the temperature was raised to 500 C. at a temperature increase rate of 10 C./min in a nitrogen gas (30 mL/min) stream. In this operation, 10% thermal reduction temperature was measured.

(Synthesis Example 1) Synthesis of BiF-I-1

(18) A container (internal capacity: 200 mL) equipped with a stirrer, a condenser tube, and a burette was prepared. In this container, 30 g (161 mmol) of 4,4-biphenol (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), 15 g (65 mmol) of 4-iodobenzaldehyde (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 100 mL of 4-butyrolactone were charged, and 3.9 g (21 mmol) of p-toluenesulfonic acid (reagent manufactured by Kanto Chemical Co., Inc.) was added thereto to prepare a reaction solution. This reaction solution was stirred at 90 C. for 3 hours to perform reaction. Next, the reaction solution was concentrated. The reaction product was precipitated by the addition of 50 g of heptane. After cooling to room temperature, the precipitates were separated by filtration. The solid matter obtained by filtration was dried, and then separated and purified by column chromatography to obtain 4.2 g of the objective compound represented by the following formula (BiF-I-1).

(19) As a result of measuring the molecular weight of the obtained compound by the above method, it was 586.

(20) The obtained compound was subjected to NMR measurement under the above measurement conditions. As a result, the following peaks were found, and the compound was confirmed to have a chemical structure represented by the following formula.

(21) (ppm) 9.4 (4H, OH), 6.8-7.8 (18H, Ph-H), 6.2 (1H, CH)

(22) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained compound (BiF-I-1) was 300 C. or higher. Therefore, this compound was evaluated as having high heat resistance and being applicable to baking at a high temperature.

(23) ##STR00049##

(Synthesis Example 2) Synthesis of BiF-I-2

(24) A container (internal capacity: 200 mL) equipped with a stirrer, a condenser tube, and a burette was prepared. In this container, 30 g (161 mmol) of 4,4-biphenol (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), 15 g (54 mmol) of 5-iodovanillin (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 100 mL of 4-butyrolactone were charged, and 3.9 g (21 mmol) of p-toluenesulfonic acid (reagent manufactured by Kanto Chemical Co., Inc.) was added thereto to prepare a reaction solution. This reaction solution was stirred at 90 C. for 3 hours to perform reaction. Next, the reaction solution was concentrated. The reaction product was precipitated by the addition of 50 g of heptane. After cooling to room temperature, the precipitates were separated by filtration. The solid matter obtained by filtration was dried, and then separated and purified by column chromatography to obtain 5.1 g of the objective compound represented by the following formula (BiF-I-2).

(25) As a result of measuring the molecular weight of the obtained compound by the above method, it was 632.

(26) The obtained compound was subjected to NMR measurement under the above measurement conditions. As a result, the following peaks were found, and the compound was confirmed to have a chemical structure represented by the following formula.

(27) (ppm) 9.3 (4H, OH), 6.4-7.3 (16H, Ph-H), 6.1 (1H, CH)

(28) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained compound (BiF-I-2) was 300 C. or higher. Therefore, this compound was evaluated as having high heat resistance and being applicable to baking at a high temperature.

(29) ##STR00050##

(Example 3) Synthesis of BiF-I-3

(30) A container (internal capacity: 200 mL) equipped with a stirrer, a condenser tube, and a burette was prepared. In this container, 30 g (161 mmol) of 4,4-biphenol (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), 15 g (65 mmol) of 3-iodobenzaldehyde (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 100 mL of 4-butyrolactone were charged, and 3.9 g (21 mmol) of p-toluenesulfonic acid (reagent manufactured by Kanto Chemical Co., Inc.) was added thereto to prepare a reaction solution. This reaction solution was stirred at 90 C. for 3 hours to perform reaction. Next, the reaction solution was concentrated. The reaction product was precipitated by the addition of 50 g of heptane. After cooling to room temperature, the precipitates were separated by filtration. The solid matter obtained by filtration was dried, and then separated and purified by column chromatography to obtain 4.2 g of the objective compound represented by the following formula (BiF-I-3).

(31) As a result of measuring the molecular weight of the obtained compound by the above method, it was 586.

(32) The following peaks were found by 400 MHz-.sup.1H-NMR, and the compound was confirmed to have a chemical structure of the following formula.

(33) .sup.1H-NMR: (d-DMSO, internal standard TMS)

(34) (ppm) 9.4 (4H, OH), 6.5-7.8 (18H, Ph-H), 6.4 (1H, CH)

(35) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained compound (BiF-I-3) was 300 C. or higher. Therefore, this compound was evaluated as having high heat resistance and being applicable to baking at a high temperature.

(36) ##STR00051##

(Example 4) Synthesis of Resin (BiFR-I-1)

(37) A four necked flask (internal capacity: 1 L) equipped with a Dimroth condenser tube, a thermometer, and a stirring blade and having a detachable bottom was prepared. In this four necked flask, 41.0 g (70 mmol) of BiF-I-1 obtained in Example 1 (manufactured by Mitsubishi Gas Chemical Company, Inc.), 21.0 g (280 mmol as formaldehyde) of 40% by mass of an aqueous formalin solution (manufactured by Mitsubishi Gas Chemical Company, Inc.), and 0.97 mL of 98% by mass of sulfuric acid (manufactured by Kanto Chemical Co., Inc.) were charged in a nitrogen stream, and reacted for 7 hours while refluxed at 100 C. at normal pressure. Subsequently, 180.0 g of o-xylene (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added as a diluting solvent to the reaction solution, and it was left at rest, followed by removal of an aqueous phase as a lower phase. Neutralization and washing with water were further performed, and o-xylene was distilled off under reduced pressure to obtain 52.2 g of a brown solid resin (BiFR-I-1).

(38) The obtained resin (BiFR-I-1) had Mn of 1685, Mw of 3120, and Mw/Mn of 1.85.

(39) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained resin (BiFR-I-1) was 300 C. or higher. Therefore, this compound was evaluated as being applicable to baking at a high temperature.

(Example 5) Synthesis of Resin (BiFR-I-2)

(40) A four necked flask (internal capacity: 1 L) equipped with a Dimroth condenser tube, a thermometer, and a stirring blade and having a detachable bottom was prepared. In this four necked flask, 41.0 g (70 mmol) of BiF-I-1 obtained in Example 1 (manufactured by Mitsubishi Gas Chemical Company, Inc.), 50.9 g (280 mmol) of 4-biphenylaldehyde (manufactured by Mitsubishi Gas Chemical Company, Inc.), 100 mL of anisole (manufactured by Kanto Chemical Co., Inc.), and 10 mL of oxalic acid dihydrate (manufactured by Kanto Chemical Co., Inc.) were charged in a nitrogen stream, and reacted for 7 hours while refluxed at 100 C. at normal pressure. Subsequently, 180.0 g of o-xylene (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added as a diluting solvent to the reaction solution, and it was left at rest, followed by removal of an aqueous phase as a lower phase. Neutralization and washing with water were further performed, and the solvent of the organic phase and unreacted 4-biphenylaldehyde were distilled off under reduced pressure to obtain 68.2 g of a brown solid resin (BiFR-I-2).

(41) The obtained resin (BiFR-I-2) had Mn of 2080, Mw of 3650, and Mw/Mn of 1.75.

(42) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained resin (BiFR-I-2) was 300 C. or higher. Therefore, this compound was evaluated as being applicable to baking at a high temperature.

Comparative Example 1

(43) A four necked flask (internal capacity: 10 L) equipped with a Dimroth condenser tube, a thermometer, and a stirring blade and having a detachable bottom was prepared. In this four necked flask, 1.09 kg (7 mol) of 1,5-dimethylnaphthalene (manufactured by Mitsubishi Gas Chemical Company, Inc.), 2.1 kg (28 mol as formaldehyde) of 40% by mass of an aqueous formalin solution (manufactured by Mitsubishi Gas Chemical Company, Inc.), and 0.97 mL of 98% by mass of sulfuric acid (manufactured by Kanto Chemical Co., Inc.) were charged in a nitrogen stream, and reacted for 7 hours while refluxed at 100 C. at normal pressure. Subsequently, 1.8 kg of ethylbenzene (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added as a diluting solvent to the reaction solution, and it was left at rest, followed by removal of an aqueous phase as a lower phase. Neutralization and washing with water were further performed, and ethylbenzene and unreacted 1,5-dimethylnaphthalene were distilled off under reduced pressure to obtain 1.25 kg of a light brown solid dimethylnaphthalene formaldehyde resin.

(44) The obtained dimethylnaphthalene formaldehyde had a molecular weight Mn of 562.

(45) Then, a four necked flask (internal capacity: 0.5 L) equipped with a Dimroth condenser tube, a thermometer, and a stirring blade was prepared. In this four necked flask, 100 g (0.51 mol) of the dimethylnaphthalene formaldehyde resin thus obtained and 0.05 g of p-toluenesulfonic acid were charged under a nitrogen stream. The temperature was raised to 190 C., and it was heated for 2 hours, and then stirred. Subsequently, 52.0 g (0.36 mol) of 1-naphthol was further added thereto. The temperature was further raised to 220 C., and it was reacted for 2 hours. After dilution with a solvent, neutralization and washing with water were performed, and the solvent was removed under reduced pressure to obtain 126.1 g of a blackish brown solid modified resin (CR-1).

(46) The obtained resin (CR-1) had Mn of 885, Mw of 2220, and Mw/Mn of 4.17.

(47) As a result of thermogravimetry (TG), the 10% thermal reduction temperature of the obtained resin (CR-1) was lower than 350 C.

(48) [Evaluation Method]

(49) (1) Test on Safe Solvent Solubility of Compound

(50) The solubility of the compound in cyclohexanone (CHN), propylene glycol monomethyl ether (PGME), and propylene glycol monomethyl ether acetate (PGMEA) was evaluated according to the following standard using the dissolution amount in each solvent. For the measurement of the dissolution amount, the compound was precisely weighed into a test tube at 23 C., and the target solvent was added thereto at a predetermined concentration. Ultrasound was applied for 30 minutes in an ultrasonic cleaning machine. Then, the state of the liquid was visually observed.

(51) Evaluation A: 20% by massdissolution amount

(52) Evaluation B: 10% by massdissolution amount<20.0% by mass

(53) Evaluation C: Dissolution amount<10% by mass

(54) (2) Preparation of Resist Composition

(55) Each component was prepared according to Table 1 into a homogeneous solution, which was then filtered through a Teflon membrane filter with a pore diameter of 0.1 m to prepare a resist composition.

(56) As the acid generating agent (C), the acid crosslinking agent (G), the acid diffusion controlling agent (E), and the solvent, the followings were used:

(57) Acid Generating Agent (C)

(58) P-1: triphenylbenzenesulfonium trifluoromethanesulfonate (Midori Kagaku Co., Ltd.)

(59) Acid Crosslinking Agent (G)

(60) C-1: NIKALAC MW-100LM (Sanwa Chemical Co., Ltd.)

(61) Acid Diffusion Controlling Agent (E)

(62) Q-1: trioctylamine (Tokyo Kasei Kogyo Co., Ltd.)

(63) Solvent

(64) S-1: propylene glycol monomethyl ether (Tokyo Kasei Kogyo Co., Ltd.)

(65) (3) Storage Stability of Resist Composition and Thin Film Formation

(66) Each prepared resist composition was evaluated for its storage stability by the following procedures. The resist composition thus prepared was left at rest at 23 C. for 3 days, and evaluated by visually observing the presence or absence of precipitates. A homogeneous solution without precipitates was evaluated as , and a solution having precipitates was evaluated as x.

(67) Also, a clean silicon wafer was spin coated with the resist composition in a homogeneous state, and then prebaked (PB) before exposure in an oven of 110 C. to form a resist film with a thickness of 40 nm. The formed resist film was evaluated as when a good thin film was formed, and evaluated as x when the formed film has defect.

(68) (4) Patterning Evaluation of Resist Composition

(69) Each resist composition was evaluated for patterning by the following procedures. A clean silicon wafer was spin coated with the homogeneous resist composition, and then prebaked (PB) before exposure in an oven of 110 C. to form a resist film with a thickness of 60 nm. The resist film was irradiated with electron beams of 1:1 line and space setting with a 50 nm interval, a 40 nm interval, and a 30 nm interval using an electron beam lithography system (ELS-7500 manufactured by ELIONIX INC.). After electron beam irradiation, it was heated at each predetermined temperature for 90 seconds, and immersed in 2.38% by mass TMAH alkaline developing solution for 60 seconds for development. Subsequently, it was washed with ultrapure water for 30 seconds, and dried to form a negative type resist pattern. The line and space were observed by a scanning electron microscope (S-4800 manufactured by Hitachi High-Technologies Corporation) to evaluate the reactivity of the resist composition by electron beam irradiation.

(70) Solubility in a safe solvent was evaluated by the above method. The results are shown in Table 1.

(71) The storage stability of the obtained composition and thin film formation were evaluated by the above methods. The results are shown in Table 1.

(72) TABLE-US-00001 TABLE 1 Resist performance evaluation Resist composition Acid Com- gener- Acid Acid pound ating cross- diffusion of agent linking controlling Safety solvent synthesis (C) agent agent Thin solubility test example P-1 (G) (E) Solvent Storage film Compound CHN PGME PGMEA [g] [g] C-1 [g] Q-1 [g] S-1 [g] stability formation Example 1 BiF-I-1 A A A 1.0 0.3 0.3 0.03 50.0 Example 2 BiF-I-2 A A A 1.0 0.3 0.3 0.03 50.0 Example 3 BiF-I-3 A A A 1.0 0.3 0.3 0.03 50.0 Example 4 BiFR-I-1 B B B 1.0 0.3 0.3 0.03 50.0 Example 5 BiFR-I-2 B B B 1.0 0.3 0.3 0.03 50.0 Comparative CR-1 B B C 1.0 0.3 0.3 0.03 50.0 x x Example 1

(73) As is evident from Table 1, it was able to be confirmed that heat resistance and solubility were good in Examples 1 to 5 whereas Comparative Example 1 was inferior in heat resistance and solubility.

(74) Furthermore, Examples 1 to 5 were confirmed to be free from precipitates and produce good storage stability (evaluation: ). On the other hand, the resist of Comparative Example 1 manifested precipitates and was confirmed to have poor storage stability (evaluation: x).

(75) Moreover, the resist compositions obtained in Examples 1 to 5 were confirmed to form a good thin film (evaluation: ). On the other hand, the resist composition obtained in Comparative Example 1 formed a film with defect and was confirmed to form a poor thin film (evaluation: x).

(76) Pattern evaluation was carried out using the resist compositions of Examples 1 to 5 and Comparative Example 1 according to the above method. In Examples 1 to 5, a good resist pattern was obtained by irradiation with electron beams of 1:1 line and space setting with a 50 nm interval. On the other hand, it was confirmed that a good resist pattern was not obtained in Comparative Example 1.

(77) As seen in the above results, the resist base material of the present embodiment has high heat resistance and solubility in a safe solvent, has good storage stability, forms a good thin film, and can impart a good shape to a resist pattern, as compared with a resist base material containing the comparative compound (CR-1).

(78) As long as the above configuration of the present invention is met, resist base materials other than those described in examples also exhibit the same effects.

(79) This application is based on Japanese Patent Application No. 2015-069991 filed with JPO on Mar. 30, 2015, the entire contents of which are hereby incorporated by reference.

(80) The resist base material of the present invention has high heat resistance, has high solubility in a safe solvent, is excellent in storage stability, enables the formation of a good thin film, and imparts a good shape to a resist pattern. Thus, the present invention has industrial applicability in the field of semiconductors, the field of displays, photomasks, thin film magnetic heads, compound semiconductors, research and development, and the like in which a resist composition such as an acid amplification type non-polymer based resist material is used.