JPH1129612A - High polymeric compound introduced with functional group having unshared electron pair in terminal, its production and positive-type resist material using the same high polymeric compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the new subject compound useful as positive type resist materials for visible light, ultraviolet light, electron beam and X ray. SOLUTION: The subject compound is a compound expressed by formula I [R is an initiator fragment; R1 is H, an organosilyl, etc.; R2 to R4 are each H, a 1-10C alkyl, etc.; X is a substituent having unshared electron pair such as 0, N, S, etc.; (n) is 5-10000], e.g. a compound of formula II. The compound of formula I is obtained by ionically polymerizing a vinyl monomer (e.g. α- methylstyrene, etc.), in the presence of 0.001-1 times molar of an organometal- based initiator (e.g. butyllithium, sodiumnaphthalene, etc.), then, adding or condensing a ketone, an imine, carbon disulfide, a halomethyl ether, a halomethyl sulfide preferably in the presence of 0.5-100 times based on the amount of the monomer of an inert solvent (e.g. tetrahydrofuran, etc.), at -100-0 deg.C for 10 minutes -100 hours to introduce functional groups each having an unshared electron pair through one carbon atom to the terminal quaternary carbon in the main chain of the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer obtained by ion-polymerizing a vinyl monomer in the presence of an organometallic initiator and then adding or condensing a ketone, imine, carbon disulfide, halomethyl ether, or halomethyl sulfide. The present invention relates to a novel polymer compound in which a functional group having an unshared electron pair is introduced into the terminal quaternary carbon of the main chain via one carbon atom, a method for producing the same, and a positive resist material using the compound.

[0002]

2. Description of the Related Art Conventionally, a method of introducing an unsaturated group into a terminal of a polymer compound has been widely attempted as a method for synthesizing a macromonomer (edited by Yuya Yamashita, Chemistry and Industry of Macromonomer, IPC Publishing, 1987). However, at present, most of them have been synthesized as precursors of block polymers and graft polymers. Therefore, most of the polymers obtained as macromonomers show a polymerization reaction by light or electron beam. The present inventors have shown a positive resist that efficiently exhibits a reaction activity by irradiation with light or an electron beam, depolymerizes the resulting active species by having the same structure as a growing chain, and efficiently depolymerizes. Aimed and studied repeatedly. In general, in the cationic polymerization reaction of a vinyl monomer, a polymer represented by the structural formula (C) is partially generated by a chain transfer reaction (proton transfer). Example in which the 2-phenylallyl terminal structure was successfully introduced into the terminal quantitatively in high yield by the production method described in Japanese Patent Application No. 6-228039 (Japanese Patent Application Laid-Open No. 8-92312). There is only. In particular, a polymer having α-methylstyrene in the repeating skeleton efficiently undergoes depolymerization from the end by electron beam irradiation or the like,
Provide efficient positive electron beam resist. Poly (α-
A resist having (methylstyrene) as the main chain skeleton has extremely high resolution performance due to the low perturbation of the polymer itself, but the sensitivity of the electron beam to the 2-phenylallyl terminal is not always high.

[0003]

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[0004]

Accordingly, the present inventors have developed a polymer obtained by polymerizing a vinyl monomer such as α-methylstyrene using an organometallic initiator in order to improve the sensitivity to an electron beam or the like. As a result of intensive studies on the technology for improving the electron beam sensitivity at the terminal, the introduction of a functional group having an unshared electron pair via one carbon atom into the terminal quaternary carbon of the polymer main chain provides high efficiency. It has been discovered that a polymer compound that can be decomposed by an electron beam or the like can be obtained, and the present invention has been completed.
An object of the present invention is to provide a polymer compound having the structural formula (A) having improved sensitivity to an electron beam, a method for producing the same, and a resist material such as an electron beam using the compound of the structural formula (A).

[0005]

The gist of the invention according to claim 1 is that the terminal quaternary carbon of the polymer main chain represented by the following structural formula (A) has a lone electron via one carbon atom. The invention according to claim 3 is a method for producing a polymer having a structural formula (A), and the invention according to claim 3 is a polymer compound having a structural group (A). It is a resist material such as an electron beam using a polymer. The compound (A) of the present invention comprises a ketone, an imine, carbon disulfide, a halomethyl ether, a living anion terminal obtained by anionic polymerization of a vinyl monomer using an organic metal such as butyllithium or sodium naphthalene as an initiator. It is synthesized by adding or condensing halomethyl sulfide or the like to modify the terminal. When the modification process of the terminal of this synthesis process is used as an organic lithium initiator and acetone is used as a modifier, the reaction for modifying a polymer having lithium at the terminal carbon of the polymer with acetone is as follows. .

[0006]

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As the monomers used in this reaction, any monomers can be used as long as they are capable of anionic polymerization in a living manner. In particular, α-methylstyrenes (which may be substituted with an organic silyl group or an organic siloxy group). Is preferred. Other monomers include conjugated hydrocarbon monomers such as styrene, isoprene and butadiene, and conjugated polar monomers such as ethylene, acrylate, dialkylacrylamide and vinyl ketone.

The organometallic initiators used in this reaction are organic lithium such as methyllithium and butyllithium, organic sodium and organic potassium such as sodium naphthalene, potassium naphthalene, cumylnaphthalene and cumylpotassium, lithium diisopropylamide and potassium diisopropylamide. And the like are used. Also, α-methylstyrene living oligomers and the like can be used. These initiators are used in a molar ratio of 0.00001 to 1 relative to the monomer.
It can be used in a molar amount of 00 times, and more preferably 0.001 to 1 times.

The terminal modifier used in this reaction includes ketones such as acetone, methyl ethyl ketone and acetophenone, imines such as benzalaniline, carbon disulfide, chloromethyl methyl ether, bromomethyl methyl ether, chloromethyl phenyl sulfide, N , O-bis (trimethylsilyl) acetamide, halides such as 2-bromotetrahydrofuran, and the like. The molar ratio of these terminal modifiers to the resulting polymer can be from 0.01 to 100 moles, preferably from 1 mole to 10 moles.

[0010] The reaction of the present invention can also be carried out in the presence of an inert solvent. Examples of the solvent include ethers such as diethyl ether, dioxane, tetrahydrofuran, dimethoxyethane and diglyme; aliphatic hydrocarbons such as pentane, hexane, cyclohexane and octane; aromatic hydrocarbons such as benzene and toluene; dimethyl sulfoxide;
An aprotic polar solvent such as N-dimethylformamide and hexamethylphosphoric triamide, and a liquid that does not react with the alkali metal amide catalyst under the reaction conditions can be used. Of these, preferred are ethers such as tetrahydrofuran, aromatic hydrocarbons such as benzene, and aliphatic hydrocarbons such as hexane.

The amount of solvent used is 0.1% by volume of the monomer.
To 1000 times the amount, more preferably 0.5 times
Or 100 times the amount. The reaction generally slows down as the relative amount of solvent increases. The temperature at which the reaction is carried out in the present invention is not particularly limited, but is -150 ° C to 150 ° C.
And more preferably -100 ° C to 0 ° C. The reaction time is not limited, but is preferably 1 minute to 1000 hours, more preferably 10 minutes to 100 hours. Since the reaction rate varies depending on the reaction conditions and the target substance, it is desirable to determine the end of the reaction by quantifying the raw materials and products by gas chromatography, liquid chromatography, or the like.

Since the high molecular compound of the compound (A) obtained in the present invention has a functional group which is highly sensitive to ultraviolet light, electron beam and the like at the terminal, it is efficiently depolymerized by ultraviolet light and electron beam. The depolymerization process is as follows.

[0013]

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That is, the polymer compound of the structural formula (A) can be used as a novel high-sensitivity positive resist material because all the portions irradiated with ultraviolet rays and electron beams are depolymerized into monomers and become soluble. Therefore, formation of a resist film using the above compound (A) can be obtained by dissolving the above compound (A) in a solvent and forming a thin film with a spinner or the like. As the solvent used at that time, ethers such as diethyl ether, dioxane, tetrahydrofuran, dimethoxyethane, diglyme, pentane, hexane, cyclohexane, aliphatic hydrocarbons such as octane, benzene, aromatic hydrocarbons such as toluene, A liquid capable of dissolving the compound (A) such as an aprotic polar solvent such as dimethyl sulfoxide, N, N-dimethylformamide, and hexamerphosphoric triamide can be used.
The concentration of the solvent is 0.1 to 100 by volume of the compound (A).
It is preferably 0 times, more preferably 1 to 20 times. As the relative amount of solvent increases, the membrane generally becomes thinner.

The obtained film is made of visible light, ultraviolet light, electron beam, X-ray,
It is easily depolymerized by irradiation with a line or the like to form a pattern. Solvents used for development are water, methanol, ethanol,
Alcohols such as propanol, ketones such as methyl ethyl ketone, and hydrocarbons such as benzene and toluene are used. When irradiating electron beams, X-rays or the like under vacuum, a pattern can be obtained without using a developer.

[0016]

The present invention will be further described below with reference to examples, but these examples do not limit the scope of the present invention in any way. Example 1 Synthesis of Sample 1 of Structural Formula (D)

[0017]

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The inside of the reaction vessel was purged with argon, and was cooled to -78 ° C.
Below, 8.2 ml of tetrahydrofuran, 0.34 ml of a hexane solution of sec-butyllithium and 1.3 ml of α-methylstyrene are added, and polymerization is carried out for 30 minutes. 2 ml of acetone was added to this solvent, and the mixture was further reacted for 3 minutes. This solvent was added to a large excess of methanol to obtain a polymer. The polymer was obtained quantitatively. The molecular weight and molecular weight distribution determined by gel permeation chromatography (GPC) were 5000 and 1.08, respectively.

Example 2 Synthesis of Sample 2 of Structural Formula (E)

[0020]

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1 g of benzalaniline instead of acetone
A polymer was synthesized under exactly the same conditions as in Example 1, except that 3 ml of a tetrahydrofuran (THF) solution was used. Gel permeation chromatography (GP
The molecular weight and the molecular weight distribution obtained from C) were 500
0 and 1.08.

Characteristics of Samples 1 and 2 as Resist Example 3 A 10% toluene solution of Sample 1 obtained in Example 1 was spin-coated to form a film having a thickness of 0.5 μm, and the film was formed with a scanning electron microscope at 20 Kev. Electron beam irradiation was performed. Developing with methyl ethyl ketone containing 40% methanol and determining the sensitivity characteristic curve (FIG. 1), the electron beam irradiation intensity at the time of 50% residual film thickness was 35 μC / cm 2, and the slope (γ) was 4.0.
Met.

Example 4 An electron beam writing characteristic was examined in exactly the same manner as in Example 3 except that the sample 2 obtained in Example 2 was used. From the sensitivity characteristic curve of FIG. 2, the electron beam irradiation intensity at the time of 50% residual film thickness was 3 μC / cm 2, and the slope (γ) thereof was 4.0.

[0024]

The vinyl polymer having a quaternary carbon in the main chain is known to have a low ceiling temperature and to be decomposable to light and electron beams. It does not show high performance as a resist. Here, by introducing a functional group having an unshared electron pair into the terminal quaternary carbon of the polymer main chain quantitatively through one carbon atom as in the present invention, the electron beam responds to the electron beam with high efficiency. A system in which decomposition progresses quantitatively from the terminal can be achieved. Furthermore, since poly (α-methylstyrene) has a high glass transition point and suppresses molecular perturbation and has a low molecular weight distribution, such a system has extremely high resolution and high-order fine processing. It is a useful material in the semiconductor field that requires technology.

[Brief description of the drawings]

FIG. 1 is an electron beam sensitivity characteristic curve of a polymer obtained in Example 1.

FIG. 2 is an electron beam sensitivity characteristic curve of the polymer obtained in Example 2.

Claims (4)

[Claims] 1. A polymer having a terminal functional group in which a functional group having an unshared electron pair is introduced into a terminal quaternary carbon of a polymer main chain represented by the following structural formula (A) through one carbon atom. Compound. Embedded image [Wherein R represents any initiator fragment. R ₁ is hydrogen or an organic silyl group, an organic siloxy group, R ₂ , R ₃ and R ₄
Represents hydrogen, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group. X represents a substituent having an unshared electron pair such as O, N, and S. n is 5 to 10,000
Represents an integer. ] 2. Poly (α) represented by the following structural formula (B)
The polymer compound according to claim 1, which has a (-methylstyrene) skeleton. Embedded image [Wherein, R, R ₂ , R ₃ , R ₄ , X and n are the same as described above. ] 3. A method for ionic polymerization of a vinyl monomer in the presence of an organometallic initiator, followed by addition or condensation of a ketone, imine, carbon disulfide, halomethyl ether, or halomethyl sulfide to form a terminal quaternary carbon of the polymer main chain. A method for producing a polymer compound represented by the chemical formula (A), wherein a functional group having an unshared electron pair is introduced via one carbon atom into the compound. Embedded image [Wherein, R, R ₁ , R ₂ , R ₃ , R ₄ , X and n are the same as described above. ] 4. A positive resist material for visible light, ultraviolet light, electron beam and X-ray using the compound represented by the chemical formula (A). Embedded image [Wherein, R, R ₁ , R ₂ , R ₃ , R ₄ , X and n are the same as described above. ]