JP7815983B2 - Polymer material, self-assembled film, method for producing self-assembled film, pattern, and method for forming pattern - Google Patents

Description

The present invention relates to a polymer material, a self-assembled film, a method for manufacturing a self-assembled film, a pattern, and a method for forming a pattern.

As semiconductors and other electronic components become smaller, demand for lithography technology, which can form fine patterns, is increasing.

In particular, technology using directed self-assembly (DSA), which utilizes microphase separation of block copolymers, is attracting attention as a next-generation lithography technology because it enables the formation of fine patterns at low cost.

As an example of such technology, Patent Document 1 discloses a polymer film in which a block copolymer resin composed of at least two or more types of mutually incompatible polymers bonded at their ends is placed on a substrate having a surface roughness of at least 1 nm, resulting in a block copolymer film having a microdomain structure oriented perpendicular to the substrate surface, and the block copolymer resin is a mixture of at least two or more types of block copolymer resins with different molecular weights.

Japanese Patent Application Laid-Open No. 2005-8701

The inventors have examined conventional induced self-assembly materials and found that when the half pitch (hp) of the pattern to be formed is small and uniform and a composition (polymer block configuration or weight average molecular weight) that can form an induced self-assembly film (also simply referred to as a self-assembly film) that has film strength is used, there is a problem in that the etching resistance during dry etching decreases.
In other words, conventional guided self-assembly materials have not been able to form patterns with small and uniform half pitches (hp), have film strength, and exhibit excellent etching resistance during dry etching, and there is still room for further improvement.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a polymeric material capable of forming a self-assembled film that has a small and uniform half pitch (hp) of the formed pattern, has film strength, and exhibits excellent etching resistance during dry etching.

After extensive research into the above-mentioned problems, the inventors discovered that in a multiblock copolymer formed by linking a first polymerization block, which is a random copolymer containing a structural unit represented by general formula (1) described below and a structural unit represented by general formula (3) described below, with a second polymerization block containing a structural unit represented by general formula (4) described below, by adjusting the structural unit represented by general formula (3) described below constituting the first polymerization block to a predetermined weight ratio, the formed pattern has a small and uniform half pitch (hp) and can be made strong. Furthermore, they discovered that the etching resistance of the multiblock copolymer can be improved by irradiating it with UV or EB (electron beam) after film formation, leading to the present invention.

That is, the present invention relates to a multiblock copolymer comprising a first polymer block, which is a random copolymer comprising a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (3), and a second polymer block comprising a structural unit represented by the following general formula (4), linked together, wherein the first polymer block comprises 1 to 49 mol % of the structural unit represented by the following general formula (3) relative to the entire first polymer block; a self-assembled monolayer obtained using the polymer material; a method for producing a self-assembled monolayer using the polymer material; a pattern obtained by etching the self-assembled monolayer; and a method for forming a pattern, including the step of etching the self-assembled monolayer to form a pattern.

[In general formula (1), ^R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, a represents an integer of 1 or more and 1,000 or less, and X represents a substituent represented by general formula (2)]
[In general formula (2), b is an integer of 1 or more and 8 or less.]
[In general formula (3), ^R2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and c represents an integer of 1 to 1,000.]
[In general formula (4), ^R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and d represents an integer of 1 to 1,000.]

The present invention provides a polymeric material capable of forming a self-assembled film that has a small and uniform half pitch (hp) of the formed pattern, has film strength, and exhibits excellent etching resistance during dry etching.

<Polymer materials>
The polymer material of the present invention contains a multiblock copolymer obtained by linking a first polymerization block, which is a random copolymer containing a constitutional unit represented by the following general formula (1) and a constitutional unit represented by the following general formula (3), with a second polymerization block containing a constitutional unit represented by the following general formula (4), and the first polymerization block contains 1 to 49 mol % of the constitutional unit represented by the following general formula (3) with respect to the entire first polymerization block:

[In general formula (1), ^R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, a represents an integer of 1 or more and 1,000 or less, and X represents a substituent represented by general formula (2)]
[In general formula (2), b is an integer of 1 or more and 8 or less.]
[In general formula (3), ^R2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and c represents an integer of 1 to 1,000.]
[In general formula (4), ^R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and d represents an integer of 1 to 1,000.]

The directed self-assembly (DSA) technique utilizes the ability to form microphase separation, which occurs when two types of polymer chains that are incompatible with each other are linked at one point by copolymerization.
In multiblock copolymers linked by covalent bonds, when identical polymer components aggregate together and undergo microphase separation, the interfacial curvature during molecular aggregation changes depending on the volume fraction ratio (f) between the two polymer components, resulting in a change in the microdomain structure.

Known microdomain structures formed by two polymer components (e.g., a first polymer block and a second polymer block) include a spherical structure in which the first polymer block is finely dispersed in the second polymer block, a cylindrical structure in which the first polymer block is linearly dispersed in the second polymer block, a gyroid structure in which a plurality of first polymer blocks dispersed in the second polymer block are bonded to each other, and a lamellar structure in which the second polymer block and the first polymer block are laminated in layers.
The polymer material of the present invention may exhibit any of the above microdomain structures, but from the viewpoint of semiconductor pattern formation, it is preferable that the polymer material exhibit a lamellar structure or a cylindrical structure.
First, the first polymer block will be described.

(First polymer block)
The first polymer block is a random copolymer composed of a constitutional unit represented by the above general formula (1) and a constitutional unit represented by the above general formula (3).

There are no particular limitations on R ¹ in the general formula (1) and R ² in the general formula (3) as long as they are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.
Among these, R ¹ and R ² are preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, from the viewpoint of being able to reduce defects due to poor microphase separation sites and to form fine and minute repeating patterns.

In the above general formula (2), b is an integer of 1 or more and 8 or less.
From the viewpoint of reducing the half pitch (hp), b is preferably 1 or 2, and more preferably 1.

The first polymer block contains 1 to 49 mol % of the constitutional unit represented by the above general formula (3) based on the entire first polymer block.
By including the constitutional unit represented by the general formula (3) in the above proportion relative to the entire first polymer block, etching resistance can be improved by irradiation with UV or EB (electron beam).
The first polymer block preferably contains 2 to 30 mol %, and more preferably 5 to 15 mol %, of the structural unit represented by the general formula (3) relative to the entire first polymer block.

The first polymer block preferably contains 20 to 99 mol %, and more preferably 50 to 95 mol %, of the structural unit represented by general formula (1) above, relative to the entire first polymer block.

The first polymer block may further include a constitutional unit represented by the following general formula (5).
By including a structural unit represented by the following general formula (5), it is possible to reduce the amount of the expensive compound used that leads to a structural unit represented by the above-mentioned general formula (1).

[In general formula (5), ^R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and e represents an integer of 1 to 1,000.]

R ⁴ in the above general formula (5) is not particularly limited as long as it is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and the substituents exemplified for R ¹ and R ² above can be applied.
Among these, ^R4 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, from the viewpoint of being able to reduce defects due to poor microphase separation sites and to form fine and minute repeating patterns.

The first polymer block preferably contains 20 to 70 mol %, and more preferably 35 to 45 mol %, of the structural unit represented by general formula (5) above, relative to the entire first polymer block.

The first polymer block can be, for example, a first polymer block A formed by repeated random polymerization of a structural unit represented by the above general formula (1) and a structural unit represented by the above general formula (3), or a first polymer block B formed by repeated random polymerization of a structural unit represented by the above general formula (1), a structural unit represented by the above general formula (3), and a structural unit different from the structural units represented by the above general formulas (1) and (3) (for example, a structural unit represented by the above general formula (5)).

(Second Polymer Block)
The second polymer block contains a constitutional unit represented by the above general formula (4).

^R3 in the general formula (4) is not particularly limited as long as it is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.
Among these, ^R3 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, from the viewpoint of being able to reduce defects due to poor microphase separation sites and to form fine and minute repeated patterns.

As the second polymer block, for example, a second polymer block C formed by repeatedly polymerizing the same constitutional unit represented by the general formula (4) above, or a second polymer block D formed by repeatedly polymerizing a constitutional unit represented by the general formula (4) above and a constitutional unit different from the general formula (4) above can be used.
Examples of structural units different from those of the general formula (4) include structural units represented by the general formula (5).

The second polymer block preferably contains 80 to 100 mol % of the structural unit represented by general formula (4) above, based on the entire second polymer block.

(multiblock copolymer)
The multiblock copolymer is formed by linking the first polymer block and the second polymer block described above.

The multiblock copolymer is preferably a diblock copolymer or higher.

As the diblock copolymer, a copolymer in which the above-mentioned first polymer blocks A and B and second polymer blocks C and D are arranged in any order such as AC, AD, BC, or BD can be used.
From the viewpoint of being able to reduce defects due to poor microphase separation sites and being able to form fine and minute repeating patterns, an arrangement of a first polymerization block A obtained by repeatedly randomly polymerizing a constitutional unit represented by the above general formula (1) and a constitutional unit represented by the above general formula (3), and a second polymerization block C obtained by repeatedly polymerizing the same constitutional unit represented by the above general formula (4) is preferred.

Even when the multiblock copolymer is a triblock copolymer or greater, from the viewpoint of reducing defects due to poor microphase separation sites and enabling the formation of fine and minute repeating patterns, it is preferable that the first polymer block A and the second polymer block C are arranged alternately, for example, in the form of (ACA), (CAC), (ACACAC), or (CACACA).

Preferably, the multi-block copolymer is a hexa-block copolymer or smaller.
This is because it is difficult to synthesize a heptablock copolymer or a multiblock copolymer.

In terms of the ratio of the constituent units of the multiblock copolymer, from the viewpoint of improving the uniformity and regularity of the pattern of the microdomain structure formed by self-assembly, it is preferable that the molar ratio of the first polymer block to the second polymer block (moles of the first polymer block:moles of the second polymer block) be within the range of 8:2 to 2:8.

When the above-mentioned lamellar structure or cylindrical structure is preferably formed, the molar ratio of the first polymer block to the second polymer block (moles of the first polymer block:moles of the second polymer block) is more preferably within the range of 4:6 to 6:4, and even more preferably 5:5, from the viewpoint of improving the uniformity and regularity of the pattern of the microdomain structure formed by self-assembly.

The multiblock copolymer preferably has a number average molecular weight (Mn) of 3,000 or more and 50,000 or less, from the viewpoint of improving the uniformity and regularity of the pattern of the microdomain structure formed by self-organization.
When the number-average molecular weight (Mn) is 3,000 or more, self-assembly proceeds to form a self-assembled film having a microdomain structure, and when the number-average molecular weight (Mn) is 50,000 or less, hydrogen bonds possessed by the hydrophilic groups of the polymer compound function appropriately, making it easy to achieve a pattern size of 10.0 nm or less.
The number average molecular weight (Mn) is more preferably 5,000 or more, and even more preferably 6,000 or more, and more preferably 20,000 or less.

The molecular weight distribution (PDI: Mw/Mn=PDI) of the multiblock copolymer is preferably 1.0 or more, more preferably 1.02 or more, and is preferably 1.1 or less, more preferably 1.05 or less, from the viewpoint of being able to reduce defects due to poor microphase separation sites and being able to form fine and minute repeated patterns.
If the PDI is 1.0 or more and 1.1 or less, there is almost no contamination with low-molecular-weight polymers and high-molecular-weight polymers, and therefore the uniformity and regularity of the pattern of the microdomain structure formed by self-organization are improved.

The above-mentioned number average molecular weight (Mn) and PDI (as well as weight average molecular weight Mw) are measured by gel permeation chromatography (GPC) using polystyrene as the standard. The number average molecular weight measured by GPC is measured, for example, using a GPC measuring device (trade name: HLC-8120, manufactured by Tosoh Corporation), a column (trade name: TSK GELGMH6, manufactured by Tosoh Corporation), and a mobile phase (THF) at a column temperature of 40°C, and calculated using a calibration curve of standard polystyrene.

The composition ratio of the multiblock copolymer can be determined by nuclear magnetic resonance (NMR) spectroscopy.
The composition ratio by the NMR method can be measured, for example, under the conditions of an NMR measurement device (trade name "JNM-ECZ400R", manufactured by JEOL, analysis software: Delta5.3.1, frequency: 400 MHz), temperature: 25°C, solvent (CDCl ₃ ), internal standard: tetramethylsilane (TMS), and accumulation number: 16.
The composition of the multiblock copolymer means the constituent units that make up the multiblock copolymer, and the composition ratio means the molar ratio of the constituent units that make up the multiblock copolymer.

The multi-block copolymer is preferably copolymerized by living anionic polymerization.
A multiblock copolymer of a first polymerization block mainly composed of a constitutional unit represented by the general formula (1) above and a constitutional unit represented by the general formula (3) above, which are copolymerized by living anionic polymerization, and a second polymerization block mainly composed of a constitutional unit represented by the general formula (4) above is preferred.
By copolymerizing polymer materials by living anionic polymerization, it is possible to narrow the PDI and precisely obtain polymer compounds with desired number-average molecular weights, thereby improving the uniformity and regularity of the microdomain structure patterns formed by self-organization.

There are no particular limitations on the method for producing a polymer compound that is a multiblock copolymer, as long as it can copolymerize the first polymer block and the second polymer block.
Polymerization methods for obtaining polymeric materials include living anionic polymerization, living cationic polymerization, living radical polymerization, and coordination polymerization using an organometallic catalyst. Among these, living anionic polymerization is preferred because it causes less deactivation and side reactions during polymerization and allows living polymerization.

In living anionic polymerization, a polymerization monomer and an organic solvent that have been subjected to deoxidation and dehydration treatment are used.
Examples of organic solvents include hexane, cyclohexane, toluene, benzene, diethyl ether, and tetrahydrofuran. In living anionic polymerization, a required amount of anionic species is added to these organic solvents, and then monomers are added as needed to carry out polymerization. Examples of anionic species include organic metals such as alkyllithium, alkylmagnesium halide, sodium naphthalene, and alkylated lanthanoid compounds.
Since a substituted styrene is copolymerized as a monomer, among these, s-butyllithium and butylmagnesium chloride are preferred as the anion species.
The polymerization temperature for living anionic polymerization is preferably in the range of −100° C. or higher and 50° C. or lower, and from the viewpoint of facilitating control of the polymerization, it is more preferably −70° C. or higher and 40° C. or lower.

As a method for producing a block copolymer (first polymer block) having a constitutional unit represented by the general formula (1) above and a constitutional unit represented by the general formula (3) above, for example, a block copolymer is synthesized by living anionic polymerization of a compound that imparts a constitutional unit represented by the general formula (1) above, such as 4-trimethylsilylstyrene, with 4-(3-butenyl)styrene or the like under the conditions described above.
As a method for producing a block copolymer (second polymer block) having a constitutional unit represented by general formula (4), for example, a block copolymer is synthesized by living anionic polymerization of a substituted styrene monomer in which a phenolic hydroxyl group is protected, such as p-(1-ethoxyethoxy)styrene, under the conditions described above.
This block copolymer can deprotect the phenolic hydroxyl groups of the resulting polymer compound using an acid catalyst such as oxalic acid. Protective groups for the phenolic hydroxyl groups during polymerization include, in addition to the p-(1-ethoxyethoxy) group, a t-butyl group, a trialkylsilyl group, and the like.
When a monomer having another ether moiety or ester moiety is copolymerized in a polymer compound, it is also possible to obtain a phenolic hydroxyl group by selectively deprotecting the phenolic hydroxyl group by adjusting the acidity during the deprotection reaction and conducting the deprotection reaction under alkaline conditions.

<Self-assembled film>
The self-assembled film of the present invention can be obtained using the above-described polymer material of the present invention.
The polymer material of the present invention is preferably used for self-assembly (formation of a self-assembled film) because it can form a self-assembled film that has a small and uniform half pitch (hp) of the pattern formed, has film strength, and has excellent etching resistance during dry etching.

The self-assembled film of the present invention can be obtained by dissolving the polymer material of the present invention in an organic solvent and applying the solution.

The organic solvent is not particularly limited as long as it can produce a self-assembled monolayer, and examples thereof include butyl acetate, amyl acetate, cyclohexyl acetate, 3-methoxybutyl acetate, methyl ethyl ketone, methyl amyl ketone, cyclohexanone, cyclopentanone, 3-ethoxyethyl propionate, 3-ethoxymethyl propionate, 3-methoxymethyl propionate, methyl acetoacetate, ethyl acetoacetate, diacetone alcohol, methyl pyruvate, ethyl pyruvate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monomethyl ether propionate. Examples of suitable solvents include propylene glycol monoethyl ether propionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, 3-methyl-3-methoxybutanol, N-methylpyrrolidone, dimethyl sulfoxide, γ-butyrolactone, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, methyl lactate, ethyl lactate, propyl lactate, and tetramethylene sulfone. These solvents may be used alone or in combination of two or more.

The organic solvent is preferably propylene glycol alkyl ether acetate or alkyl lactate. Examples of propylene glycol alkyl ether acetate include those in which the alkyl group has 1 to 4 carbon atoms. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl. Of these, methyl and ethyl are preferred. Furthermore, propylene glycol alkyl ether acetate has three isomers depending on the combination of substitution positions, including 1,2-substituted and 1,3-substituted isomers. These isomers may be used alone, or two or more isomers may be used in combination.

Examples of alkyl lactate esters include those in which the alkyl group has 1 to 4 carbon atoms. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups. Of these, methyl and ethyl groups are preferred.

Regarding the concentration of the organic solvent, for example, when propylene glycol alkyl ether acetate is used, the concentration of propylene glycol alkyl ether acetate is preferably 50% by mass or more relative to the total mass of the organic solvent, and when alkyl lactate is used, the concentration is preferably 50% by mass or more relative to the total mass of the organic solvent.
When a mixed solvent of propylene glycol alkyl ether acetate and alkyl lactate is used as the organic solvent, the total amount of the mixed solvent is preferably 50% by mass or more based on the total mass of the organic solvent.
When this mixed solvent is used, it is preferable that the proportion of propylene glycol alkyl ether acetate is 60% by mass or more and 95% by mass or less, and the proportion of alkyl lactate is 5% by mass or more and 40% by mass or less. By using propylene glycol alkyl ether acetate at 60% by mass or more, the coatability of the polymer material becomes good, and by using propylene glycol alkyl ether acetate at 95% by mass or less, the solubility of the polymer material is improved.

There are no particular restrictions on the concentration of the solution in which the polymer material of the present invention is dissolved in an organic solvent, as long as it allows a self-assembled film to be obtained using a conventionally known film-forming method. For example, the organic solvent is preferably 5,000 to 50,000 parts by weight, and more preferably 7,000 to 30,000 parts by weight, per 100 parts by weight of the solid content of the polymer material.

The self-assembled film of the present invention can be produced by applying a solution in which the polymer material of the present invention is dissolved in an organic solvent.
The method for applying the solution in which a polymer material is dissolved in an organic solvent is not particularly limited as long as it can produce a self-assembled film, and examples thereof include spin coating, dipping, flexographic printing, inkjet printing, spraying, potting, and screen printing.
The present invention also encompasses a method for producing a self-assembled film by forming a self-assembled film using the polymer material of the present invention.

The self-assembled film of the present invention is preferably coated with a top coating agent on its surface, as this seals and protects the self-assembled film, improving the handling and weather resistance of the self-assembled film.

Examples of the top coating agent include polyester-based top coating agents, polyamide-based top coating agents, polyurethane-based top coating agents, epoxy-based top coating agents, phenol-based top coating agents, (meth)acrylic-based top coating agents, polyvinyl acetate-based top coating agents, polyolefin-based top coating agents such as polyethylene aluminum and polypropylene, and cellulose-based top coating agents.
The coating amount (solid content equivalent) of the top coating agent is preferably 3 g/m ² or more and 7 g/m ² or less.
The top coating agent can be applied to the self-assembled monolayer by a conventionally known application method.
The present invention also encompasses a method for producing a self-assembled film, which includes a step of applying a top coating agent onto the self-assembled film.

The self-assembled film of the present invention may be coated with an undercoating agent.
As the undercoating agent, various conventionally known undercoating agents can be used.

The self-assembled film of the present invention preferably forms a self-assembled film within a guide pattern.
In this case, for example, a solution of a polymer material can be applied to a silicon substrate with a guide pattern to form a self-assembled film.
Then, an annealing treatment is carried out at 200° C. to 300° C. for 5 minutes to 1 hour, thereby obtaining a pattern of a self-organized microdomain structure on the silicon substrate.
By etching the obtained pattern of the microdomain structure with oxygen plasma gas, an L/S (line/space) pattern and a CH (fine hole) pattern with a half pitch (hp) of 10.0 nm or less can be obtained.
The present invention also encompasses a pattern formed by etching the self-assembled film, and a method for forming a pattern including the step of etching the self-assembled film to form a pattern.

The cohesive strength of the multiblock copolymer can be evaluated by transmission electron microscope (TEM) observation and small-angle X-ray scattering (SAXS) measurement. A sample for evaluating cohesive strength can be prepared, for example, by preparing a 50 mg sample film of the multiblock copolymer, dissolving the prepared sample in 1 g of additive-free THF, transferring the sample to a Teflon dish, casting it in the Teflon dish for 10 days, and vacuum drying it.

In TEM observation, the sample film is first cut to an appropriate size and placed in an embedding mold, then epoxy resin is poured into it and the mold is left to stand at 60°C for 12 hours to harden the epoxy resin and embed the film. The embedded sample film is then cut into sections approximately 50 nm thick using a microtome, and the sections are then collected on Cu grids _, stained with _Cs2CO3 , and observed with a transmission electron microscope to measure the hp.

In SAXS measurements, for example, block copolymer powder is heat-treated on a heat-resistant film, and microphase separation in the bulk state can be measured using a small-angle X-ray scattering (SAXS) analyzer (ultrafine periodic structure analysis system, Nano-Viewer AXIS IV, manufactured by Rigaku Corporation).

In this microphase separation measurement, for example, X-rays are incident on a sample film of a block copolymer, and the angular dependence of scattering that appears on the small-angle side is measured for 60 minutes using an imaging plate. Regarding measurement data processing, background correction such as air scattering is performed to calculate q/nm ^. After performing Fourier transform analysis, the half pitch (hp) of the self-assembled monolayer, which is half the identity period (d) of the average repeating pattern size width of the microdomain structure formed by self-assembly of the block copolymer, can be measured.

This specification discloses the following:

The present disclosure (1) contains a multiblock copolymer formed by linking a first polymerization block, which is a random copolymer containing a structural unit represented by the general formula (1) above and a structural unit represented by the general formula (3), with a second polymerization block containing a structural unit represented by the general formula (4), and the first polymerization block is a polymer material containing 1 to 49 mol % of the structural unit represented by the general formula (3) above relative to the entire first polymerization block.

Disclosure (2) is a polymer material described in Disclosure (1), in which, in the above general formula (2), b is 1 or 2.

Disclosure (3) is a polymer material according to disclosure (1) or (2), in which the first polymer block further contains a structural unit represented by general formula (5).

The present disclosure (4) is a polymer material according to any one of the present disclosures (1) to (3), in which the multiblock copolymer is a diblock copolymer or greater and a hexablock copolymer or less.

The present disclosure (5) is a polymer material described in any one of the present disclosures (1) to (4), in which the multiblock copolymer is copolymerized by living anionic polymerization.

The present disclosure (6) is a polymer material described in any one of the present disclosures (1) to (5), in which the multiblock copolymer has a number average molecular weight of 3,000 or more and 50,000 or less.

The present disclosure (7) is a self-assembled monolayer obtained using the polymer material described in any one of the present disclosures (1) to (6).

The present disclosure (8) is a self-assembled monolayer described in the present disclosure (7) having a top coating agent applied to the surface.

The present disclosure (9) is a method for producing a self-assembled film, which forms a self-assembled film using a polymer material described in any one of the present disclosures (1) to (6).

The present disclosure (10) is a method for producing a self-assembled film according to the present disclosure (9), which forms a self-assembled film within a guide pattern.

The present disclosure (11) is a method for producing a self-assembled film according to the present disclosure (9) or (10), which includes a step of applying a top coating agent onto the self-assembled film.

The present disclosure (12) relates to a pattern obtained by etching the self-assembled film described in the present disclosure (7) or (8).

The present disclosure (13) is a pattern formation method including a step of etching the self-assembled film described in the present disclosure (7) or (8) to form a pattern.

Below, we will explain examples and comparative examples conducted to clarify the effects of the present invention. Note that the present invention is not limited in any way by the following examples and comparative examples.

(Example 1: Synthesis of diblock copolymer (BP-2))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 66.0 g of 4-trimethylsilylstyrene and 6.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-1).

Next, 50 g of the obtained diblock copolymer (BP-1) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-2).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-2).

<Measurement of number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (PDI) of diblock copolymer (BP-2)>
The number average molecular weight and molecular weight distribution of the obtained tetrablock copolymer (BP-2) were measured by gel permeation chromatography (GPC) under the following measurement conditions. The measurement results are shown below and in Table 2.
GPC measuring device: trade name: "HLC-8120", manufactured by Tosoh Corporation; Column: trade name: "TSK GEL GMH6", manufactured by Tosoh Corporation
Mobile phase: THF
Column temperature: 40°C
Standard material: polystyrene

GPC measurement using standard polystyrene as the standard revealed that the resulting diblock copolymer (BP-2) had an Mn of 9089, an Mw of 9453, and a PDI of 1.04.

<Measurement of composition ratio (molar ratio) of diblock copolymer (BP-2)>
The composition ratio of the diblock copolymer (BP-2) obtained was measured by nuclear magnetic resonance (NMR) spectroscopy ( ¹ H-NMR) under the following measurement conditions.
NMR measurement device: trade name "JNM-ECZ400R, manufactured by JEOL, analysis software: Delta 5.3.1")
Frequency: 400MHz
Temperature: 25℃,
Solvent: CDCl3,
Internal standard: tetramethylsilane (TMS)
Number of times accumulated: 16

It was confirmed that the signals (around 3 ppm to 4 ppm and 5 ppm) derived from the 1-ethoxyethoxy group before deprotection disappeared after deprotection. Furthermore, based on the area ratio of each signal, the composition ratio (molar ratio) of the diblock copolymer (BP-2) was determined to be [4-trimethylsilylstyrene (TMSSt) + 4-(3-butenyl)styrene (BSt)] (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53.

In the SAXS measurement, the block copolymer powder was heat-treated on a heat-resistant film, and microphase separation in the bulk state was measured using a small-angle X-ray scattering (SAXS) analyzer (ultrafine periodic structure analysis system: trade name "Nano-Viewer AXIS IV", manufactured by Rigaku Corporation).
X-rays were incident on a sample film of the block copolymer, and the angular dependence of scattering occurring on the small-angle side was measured for 60 minutes using an imaging plate. The measurement data was processed by calculating q/nm ^-1 after background correction for air scattering and other factors. After Fourier transform analysis, the half pitch (hp) of the self-assembled monolayer, which is half the identity period (d) of the average repeat pattern size width of the microdomain structure formed by self-assembly of the block copolymer, was measured.
As a result, the identity period (d) was 16.0 nm and the half pitch (hp) was 8.0 nm. The measurement results are shown in Table 2 below.

(Example 2: Synthesis of diblock copolymer (BP-4))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 71.0 g of 4-trimethylsilylstyrene and 0.7 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-3).

Next, 50 g of the obtained diblock copolymer (BP-3) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-4).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-4).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-4) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53
Mn=9069
Mw = 9432
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 16.0 nm, and hp was found to be 8.0 nm. The measurement results are shown in Table 2 below.

(Example 3: Synthesis of diblock copolymer (BP-6))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 39.0 g of 4-trimethylsilylstyrene and 33.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-5).

Next, 50 g of the obtained diblock copolymer (BP-5) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, and then 175 g of methanol and 1 g of oxalic acid were added to carry out a deprotection reaction in a nitrogen atmosphere at 40° C. for 20 hours. Next, after cooling the reaction solution to around room temperature, 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-6).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-6).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-6) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 48:52
Mn=9089
Mw = 9453
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. As a result, the identity period (d) was 20.0 nm and hp was 10.0 nm. The measurement results are shown in Table 2 below.

Example 4: Synthesis of tetrablock copolymer (BP-8)
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 33.0 g of 4-trimethylsilylstyrene and 3.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 45.0 g of 4-(1-ethoxyethoxy)styrene that had been further subjected to distillation dehydration treatment was added dropwise and reacted for 30 minutes. Furthermore, a mixed solution of 33.0 g of 4-trimethylsilylstyrene and 3.0 g of 4-(3-butenyl)styrene that had been subjected to distillation purification treatment was added dropwise, and after completion of the dropwise addition, the reaction was continued for another 30 minutes. Next, 45.0 g of 4-(1-ethoxyethoxy)styrene that had been further subjected to distillation dehydration treatment was added dropwise and reacted for 30 minutes. Thereafter, the polymerization reaction was stopped by adding 30 g of methanol, and the reaction solution was concentrated to obtain 100 g of tetrablock copolymer (BP-7).

Next, 50 g of the obtained tetrablock copolymer (BP-7) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
The resulting reaction solution was then concentrated under reduced pressure, and 100 g of THF and 100 g of acetone were added to redissolve the deprotected tetrablock copolymer. The deprotected tetrablock copolymer solution was then added to 4.5 L of ultrapure water to precipitate the tetrablock copolymer (BP-8).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of tetrablock copolymer (BP-8).

The composition ratio, Mn, Mw, and PDI of the resulting tetrablock copolymer (BP-8) were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53
Mn=9089
Mw = 9453
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 8.4 nm, and hp was 4.2 nm. The measurement results are shown in Table 2 below.

(Example 5: Synthesis of hexablock copolymer (BP-10))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 22.0 g of 4-trimethylsilylstyrene and 2.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 30.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and allowed to react for 30 minutes. A mixture of 22.0 g of 4-trimethylsilylstyrene and 2.0 g of 4-(3-butenyl)styrene that had been purified by distillation was then added dropwise, and after the dropwise addition, the reaction was allowed to continue for another 30 minutes. Next, 30.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and allowed to react for another 30 minutes. A mixture of 22.0 g of 4-trimethylsilylstyrene and 2.0 g of 4-(3-butenyl)styrene that had been purified by distillation was then added dropwise, and after the dropwise addition, the reaction was allowed to continue for another 30 minutes. Next, 30.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and allowed to react for another 30 minutes. Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a hexablock copolymer (BP-9).

Next, 50 g of the obtained hexablock copolymer (BP-9) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
The resulting reaction solution was then concentrated under reduced pressure, and 100 g of THF and 100 g of acetone were added to redissolve the deprotected hexablock copolymer. The deprotected hexablock copolymer solution was then added to 4.5 L of ultrapure water to precipitate the hexablock copolymer (BP-10).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of a hexablock copolymer (BP-10).

The composition ratio, Mn, Mw, and PDI of the resulting hexablock copolymer (BP-10) were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
Composition ratio (molar ratio) of hexablock copolymer (BP-10)
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53
Mn=9089
Mw = 9453
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 7.6 nm, and hp was 3.8 nm. The measurement results are shown in Table 2 below.

(Example 6: Synthesis of diblock copolymer (BP-12))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 20.0 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 66.0 g of 4-trimethylsilylstyrene and 6.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-11).

Next, 50 g of the obtained diblock copolymer (BP-11) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-12).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-12).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-12) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53
Mn=3223
Mw = 3352
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. As a result, the identity period (d) was 12.0 nm and hp was 6.0 nm. The measurement results are shown in Table 2 below.

(Example 7: Synthesis of diblock copolymer (BP-14))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor under reduced pressure, followed by cooling to -70°C. Next, 1.35 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 66.0 g of 4-trimethylsilylstyrene and 6.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise, while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-13).

Next, 50 g of the obtained diblock copolymer (BP-13) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-14).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-14).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-14) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
(4-trimethylsilylstyrene + 4-(3-butenyl)styrene) (TMSSt + BSt): 4-hydroxystyrene (HSt) = 47:53
Mn=46860
Mw = 48735
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. As a result, the identity period (d) was 20.0 nm and hp was 10.0 nm. The measurement results are shown in Table 2 below.

(Example 8: Synthesis of diblock copolymer (BP-16))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 72.0 g of 4-pentamethyldisilylstyrene and 5.0 g of 4-(3-butenyl)styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After the dropwise addition was completed, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-15).

Next, 50 g of the obtained diblock copolymer (BP-15) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-16).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-16).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-16) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
[4-pentamethyldisilylstyrene (PMDSSt) + 4-(3-butenyl)styrene (BSt)] (PMDSSt + BSt): 4-hydroxystyrene (HSt) = 42:58
Mn=9441
Mw = 9819
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 13.0 nm, and hp was 6.5 nm. The measurement results are shown in Table 2 below.

Example 9: Synthesis of diblock copolymer (BP-18)
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor and cooled to -70°C. Next, 7.00 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, a mixture of 44.0 g of 4-trimethylsilylstyrene, 4.0 g of 4-(3-butenyl)styrene, and 22.0 g of styrene that had been subjected to distillation and purification treatment was added dropwise while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was allowed to proceed for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (BP-17).

Next, 50 g of the obtained diblock copolymer (BP-17) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
Next, the resulting reaction solution was concentrated under reduced pressure, and then 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. Next, the deprotected diblock copolymer solution was added to 4.5 L of ultrapure water to precipitate the diblock copolymer (BP-18).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (BP-18).

The composition ratio, Mn, Mw, and PDI of the diblock copolymer (BP-18) obtained were measured by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
[4-trimethylsilylstyrene (TMSSt) + 4-(3-butenyl)styrene (BSt) + styrene (St)] (TMSSt + BSt + St): 4-hydroxystyrene (HSt) = 51:49
Mn=9632
Mw=10017
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 18.0 nm, and hp was 9.0 nm. The measurement results are shown in Table 2 below.

(Comparative Example 1: Synthesis of diblock copolymer (RBP-2))
A 5 L anionic polymerization reactor was dried under reduced pressure, and then 4,500 g of a tetrahydrofuran (THF) solution that had been subjected to distillation and dehydration treatment using metallic sodium and anthracene was poured into the reactor under reduced pressure, followed by cooling to -70°C. Next, 6.70 ml of s-butyllithium (cyclohexane solution: 2.03 mol/L) was poured into the cooled THF solution. Next, 72.0 g of 4-trimethylsilylstyrene that had been subjected to distillation and purification treatment was added dropwise, while adjusting the dropping rate so that the internal temperature of the reaction solution did not exceed -60°C. After completion of the dropwise addition, the reaction was continued for an additional 30 minutes.
Next, 90.0 g of 4-(1-ethoxyethoxy)styrene that had been further dehydrated by distillation was added dropwise and reacted for 30 minutes.
Thereafter, 30 g of methanol was added to terminate the polymerization reaction, and the reaction solution was concentrated to obtain 100 g of a diblock copolymer (RBP-1).

Next, 50 g of the obtained diblock copolymer (RBP-1) was dissolved in 300 g of THF and poured into a 1 L reaction vessel, after which 175 g of methanol and 1 g of oxalic acid were added and a deprotection reaction was carried out for 20 hours at 40° C. under a nitrogen atmosphere. Next, the reaction solution was cooled to around room temperature, and then 2 g of pyridine was added to carry out a neutralization reaction.
The resulting reaction solution was then concentrated under reduced pressure, and 100 g of THF and 100 g of acetone were added to redissolve the deprotected diblock copolymer. The deprotected diblock copolymer solution was then added to 4.5 L of ultrapure water to precipitate the diblock copolymer (RBP-2).
Thereafter, the solid component was filtered and then dried under reduced pressure at 50° C. for 20 hours to obtain 45 g of a white powder solid of diblock copolymer (RBP-2).

The resulting diblock copolymer (RBP-2) was used to measure the composition ratio, Mn, Mw, and PDI of the diblock copolymer (RBP-2) by the above-mentioned measurement methods. The measurement results are shown below and in Table 2.
4-trimethylsilylstyrene (TMSSt): 4-hydroxystyrene (HSt) = 47:53
Mn=9493
Mw = 9873
PDI = 1.04

Next, the identity period (d) and hp of the pattern created using the above-mentioned method were measured. The identity period (d) was found to be 16.0 nm, and hp was found to be 8.0 nm. The measurement results are shown in Table 2 below.

(Etching Rate Measurement)
Polymers for evaluation were prepared from the structural units of the block copolymers prepared in the Examples and Comparative Examples, and the etching rates (nm/sec) of each were measured.

The poly(4-hydroxystyrene) (PHSt) described below is a polymer having 4-hydroxystyrene (HSt) as a constituent unit.
Poly(4-trimethylsilylstyrene) (PTMSSt) is a polymer having 4-trimethylsilylstyrene (TMSSt) as a structural unit.
The TMSSt-BSt random copolymer is a random copolymer of 4-trimethylsilylstyrene and 4-(3-butenyl)styrene.
The PMDSSt-BSt random copolymer is a random polymer of 4-pentamethyldisilylstyrene and 4-(3-butenyl)styrene.
The TMSSt-BSt-St random copolymer is a random polymer of 4-trimethylsilylstyrene, 4-(3-butenyl)styrene, and styrene.

<Poly 4-hydroxystyrene (PHSt)>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 20.5 g of 4-hydroxystyrene (HSt) and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15 to 20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of poly(4-hydroxystyrene) (PHSt).

The weight average molecular weight and molecular weight distribution of the obtained poly 4-hydroxystyrene (PHSt) were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90

<Poly 4-trimethylsilylstyrene (PTMSSt)>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 20.5 g of 4-trimethylsilylstyrene (TMSSt) and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15-20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of poly(4-trimethylsilylstyrene) (PTMSSt).

The weight average molecular weight and molecular weight distribution of the obtained poly(4-trimethylsilylstyrene) (PTMSSt) were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90

<TMSSt-BSt Random Copolymer (1)>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 18.8 g of 4-trimethylsilylstyrene (TMSSt), 1.7 g of 4-(3-butenyl)styrene, and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15 to 20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of TMSSt-BSt random copolymer (1).

The weight average molecular weight and molecular weight distribution of the obtained TMSSt-BSt random copolymer (1) were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw=100000
・Molecular weight distribution (Mw/Mn) = 1.90
Composition ratio (molar ratio): TMSSt/BSt=91/9

<TMSSt-BSt Random Copolymer (2)>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 20.3 g of 4-trimethylsilylstyrene (TMSSt), 0.2 g of 4-(3-butenyl)styrene, and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15 to 20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of TMSSt-BSt random copolymer (2).

The weight average molecular weight and molecular weight distribution of the resulting TMSSt-BSt random copolymer (2) were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90
Composition ratio (molar ratio): TMSSt/BSt=99/1

<TMSSt-BSt Random Copolymer (3)>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 11.1 g of 4-trimethylsilylstyrene (TMSSt), 9.4 g of 4-(3-butenyl)styrene, and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15 to 20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of TMSSt-BSt random copolymer (3).

The weight average molecular weight and molecular weight distribution of the obtained TMSSt-BSt random copolymer (3) were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90
Composition ratio (molar ratio): TMSSt/BSt=51/49

<PMDSSt-BSt Random Copolymer>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), and equipped with a Dimroth condenser, a thermometer, and a vacuum line. The flask was then subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 19.2 g of 4-pentamethyldisilylstyrene (PMDSSt), 1.3 g of 4-(3-butenyl)styrene, and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer while bubbling with nitrogen at 0°C for 15 to 20 minutes. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Next, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by vacuum filtration. The collected precipitate was then dried under vacuum at 60°C to obtain 15 g of PMDSSt-BSt random copolymer.

The weight average molecular weight and molecular weight distribution of the obtained PMDSSt-BSt random copolymer were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90
Composition ratio (molar ratio): PMDSSt/BSt=91/9

<TMSSt-BSt-St random copolymer>
A 50 mL three-neck flask was charged with 0.063 g of 2,2'-azobis(2-isobutyronitrile) (AIBN) (manufactured by Nippon Finechem Co., Ltd.), equipped with a Dimroth condenser, a thermometer, and a vacuum line, and the flask was subjected to three cycles of reduced pressure and nitrogen purging. Subsequently, 12.9 g of 4-trimethylsilylstyrene (TMSSt), 1.2 g of 4-(3-butenyl)styrene, 6.4 g of styrene, and 20.0 g of toluene were added, and the reaction solution in the flask was stirred with a magnetic stirrer at 0°C for 15 to 20 minutes while bubbling with nitrogen. The reaction solution was then stirred for 5 hours in an oil bath while being heated to 70°C. The three-neck flask was removed from the oil bath and cooled on ice. Then, 100 g of methanol was added to the three-neck flask, and the resulting precipitate was collected by filtration under reduced pressure and dried in vacuo at 60° C. to obtain 15 g of a TMSSt-BSt-St random copolymer.

The weight average molecular weight and molecular weight distribution of the resulting TMSSt-BSt-St random copolymer were measured in the same manner as in Example 1. The measurement results are as follows.
・Mw: 100000
・Molecular weight distribution (Mw/Mn) = 1.90
Composition ratio (molar ratio): TMSSt/BSt/St=52/5/43

Each solution was prepared by dissolving 1 g of each polymer for evaluation in 99 g of propylene glycol monomethyl ether acetate. The resulting solution was applied to a silicon wafer using a spin coater (MIKASA Corporation, SPINCOATER 1H-360S). The coating was heated at 120°C for 60 seconds to form a polymer layer (film thickness approximately 600 nm) as a sample for etching rate measurement.
The polymer layer was irradiated with EB (electron beam) and then dry plasma etched with oxygen plasma at 100 W and 50 sccm. A batch-type plasma cleaner PX-250 manufactured by March Plasma Systems was used as the etching device. The thickness of the polymer layer before and after etching was measured and compared using an Filmetrics F20 to determine the etching rate (nm/sec). The measurement results are shown in Table 1.
The ratio of the etching rate of each polymer layer to the etching rate of the poly(4-hydroxystyrene) (PHSt) film was calculated as the etching rate ratio. The smaller the etching rate ratio, the higher the selectivity with which poly(4-hydroxystyrene) (PHSt), which corresponds to the second polymer block of the block copolymer, is removed by etching.

As shown in Table 1, PHSt, TMSSt-BSt random copolymer (1), TMSSt-BSt random copolymer (2), TMSSt-BSt random copolymer (3), PMDSSt-BSt random copolymer, and TMSSt-BSt-St random copolymer showed smaller etching rate ratios compared to PTMSSt.
These results confirmed that domains mainly containing the second polymer block can be removed with high selectivity from lamellar structures formed by phase separation of the block copolymers of Examples 1 to 9, which have a first polymer block corresponding to TMSSt-BSt random copolymer (1), TMSSt-BSt random copolymer (2), TMSSt-BSt random copolymer (3), PMDSSt-BSt random copolymer, or TMSSt-BSt-St random copolymer, and a second polymer block corresponding to PHSt.
The first polymer block of the copolymers prepared in Examples 1 and 4 to 7 corresponds to the TMSSt-BSt random copolymer (1), the first polymer block of the copolymer prepared in Example 2 corresponds to the TMSSt-BSt random copolymer (2), and the first polymer block of the copolymer prepared in Example 3 corresponds to the TMSSt-BSt random copolymer (3).
The first polymer block of the copolymer prepared in Example 8 corresponds to a PMDSSt-BSt random copolymer, the first polymer block of the copolymer prepared in Example 9 corresponds to a TMSSt-BSt-St random copolymer, and the first polymer block of the copolymer prepared in Comparative Example 1 corresponds to TMSSt.

<Etching resistance evaluation results>
For the Examples and Comparative Examples, the ratio of the etching rate of the polymer for evaluation corresponding to the first polymerization block to the etching rate of PHSt (corresponding to the second polymerization block of each block copolymer) was calculated as a rate ratio, and the rate ratio was evaluated according to the following criteria.
For example, in the case of Example 1, the ratio of the etching rate of the TMSSt-BSt random copolymer (1) to the etching rate of PHSt was calculated as the rate ratio, and the rate ratio was found to be 0.08.
The results are shown in Table 2.
Good: The etching rate ratio was less than 0.2.
x: The etching rate ratio was 0.2 or more.

<Half pitch (hp) evaluation results>
The half pitch (hp) of the self-assembled monolayer measured in the examples and comparative examples was evaluated according to the following criteria. The results are shown in Table 2.
◯: The half pitch (hp) of the self-assembled film was 10.0 nm or less.
×: The half pitch (hp) of the self-assembled film exceeded 10.0 nm.

From Table 2, it was confirmed that in Examples 1 to 9, the half pitch (hp) was sufficiently small and the PDI was small, so that a uniform self-assembled film could be formed, and that the etching resistance was also excellent.

Claims (12)

a first polymer block that is a random copolymer containing a constitutional unit represented by the following general formula (1) and a constitutional unit represented by the following general formula (3);
A second polymer block including a constitutional unit represented by the following general formula (4),
The present invention comprises a multiblock copolymer in which
The first polymer block is a polymer material containing 1 to 49 mol % of the constitutional unit represented by the general formula (3) relative to the entire first polymer block.
[In general formula (1), ^R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, a represents an integer of 1 or more and 1,000 or less, and X represents a substituent represented by general formula (2)]
[In general formula (2), b is 1 or 2. ]
[In general formula (3), ^R2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and c represents an integer of 1 to 1,000.]
[In general formula (4), ^R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and d represents an integer of 1 to 1,000.] The polymer material according to claim 1 , wherein the first polymer block further comprises a structural unit represented by the following general formula (5):
[In general formula (5), ^R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and e represents an integer of 1 to 1,000.] The polymer material according to claim 1 or 2, wherein the multiblock copolymer is a diblock copolymer or greater and a hexablock copolymer or smaller. The polymer material according to claim 1 or 2, wherein the multiblock copolymer is copolymerized by living anionic polymerization. The polymer material according to claim 1 or 2, wherein the multiblock copolymer has a number average molecular weight of 3,000 or more and 50,000 or less. A self-assembled monolayer obtained using the polymer material described in claim 1 or 2. The self-assembled film according to claim 6 , wherein the surface is coated with a top coating agent. A method for producing a self-assembled film, which forms a self-assembled film using the polymer material described in claim 1 or 2. The method for producing a self-assembled film according to claim 8 , wherein the self-assembled film is formed within the guide pattern. The method for producing a self-assembled film according to claim 8 , further comprising the step of applying a top coating agent onto the self-assembled film. A pattern obtained by etching the self-assembled film according to claim 6 . A method for forming a pattern, comprising the step of etching the self-assembled film according to claim 6 to form a pattern.