JP2016134580A - Patterning composition, patterning method, and block-copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a patterning composition capable of patterning with a sufficiently fine microdomain structural width, and to provide a patterning method using this patterning composition, and a block-copolymer for use in the patterning composition.SOLUTION: (A) A block-copolymer has a specific structure, and (B) a patterning composition contains an organic solvent. A patterning method and a block-copolymer using the same are also provided.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pattern forming composition, a pattern forming method, and a block copolymer.

  With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, pattern miniaturization in the lithography process is required. At present, it is possible to form a fine pattern with a line width of about 90 nm using, for example, an ArF excimer laser, but a finer pattern formation has been required.

  In response to the above requirements, several pattern forming methods using so-called self-organized phase separation structures that spontaneously form ordered patterns have been proposed. For example, a method for forming an ultrafine pattern by self-assembly using a block copolymer obtained by copolymerizing a monomer compound having one property and a monomer compound having a different property is known. (See JP2008-149447, JP2002-519728, JP2003-218383). According to this method, by annealing the composition containing the block copolymer, polymer structures having the same properties tend to gather together, so that a pattern can be formed in a self-aligning manner. Also known is a method of forming a fine pattern by self-organizing a composition containing a plurality of polymers having different properties (US Patent Application Publication No. 2009/0214823, Japanese Patent Application Laid-Open No. 2010-58403). reference).

  However, it cannot be said that the pattern obtained by the conventional pattern formation method by self-organization is sufficiently fine.

JP 2008-149447 A Japanese translation of PCT publication No. 2002-519728 JP 2003-218383 A US Patent Application Publication No. 2009/0214823 JP 2010-58403 A

  The present invention has been made based on the circumstances as described above, and the object thereof is to use a pattern forming composition capable of forming a sufficiently fine pattern and the pattern forming composition. It is to provide a pattern forming method.

The invention made to solve the above problems is
[A] A pattern-forming composition comprising a block copolymer having a structure represented by the following formula (1), and [B] an organic solvent.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ³ is a monovalent carbon atom having 1 to 6 carbon atoms. A hydrogen group, R ⁴ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group, R ⁵ is a hydroxyl group or a monovalent organic group, X is a divalent linking group, a and b is 10-5000 each independently, and c is 0-5.)
The invention made to solve the above problems is
(1) a step of forming a self-assembled film having a phase separation structure on the substrate surface using the pattern forming composition of the present invention; and (2) removing a part of the phase of the self-assembled film. It is a pattern formation method including a process.

Furthermore, the invention made to solve the above problems is
It is a block copolymer having a structure represented by the above formula (1).

  The present invention can provide a pattern forming composition capable of forming a sufficiently fine pattern and a pattern forming method using the same. The pattern forming composition and pattern forming method of the present invention are suitably used in lithography processes in the production of various electronic devices such as semiconductor devices and liquid crystal devices that are required to be further miniaturized.

In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a lower layer film | membrane on a board | substrate. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a pre pattern on a lower layer film. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after apply | coating the composition for pattern formation to the area | region on the lower layer film pinched | interposed by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after forming a self-organization film | membrane in the area | region on the lower layer film pinched | interposed by the pre pattern. In the pattern formation method of this invention, it is a schematic diagram which shows an example of the state after removing the one part phase and pre pattern of a self-organization film | membrane.

Hereinafter, embodiments of the pattern forming composition, pattern forming method, and block copolymer of the present invention will be described in detail.
<Pattern forming composition>
Self-organized (Directed Self Assembly) refers to a phenomenon of spontaneously constructing an organization or structure, not only due to control from an external factor. In the present invention, a film having a phase separation structure by self-organization (self-assembled film) is formed by applying a pattern forming composition on a substrate, and a part of the phases in the self-assembled film is formed. By removing, a pattern can be formed.

The pattern forming composition of the present invention contains [A] a block copolymer having a structure represented by the above formula (1) (hereinafter also referred to as “structure (1)”), and [B] an organic solvent. It is characterized by doing. The pattern forming composition can form a pattern having a sufficiently fine microdomain structure. The pattern forming composition may contain an optional component such as a surfactant, in addition to the [A] block copolymer, as long as the effects of the present invention are not impaired. Hereinafter, each component will be described in detail.

[[A] block copolymer]
[A] The block copolymer is a block copolymer having the structure (1), and is the block copolymer of the present invention.

  [A] The block copolymer has a structure in which a plurality of blocks including at least two types of blocks are bonded. Each of the blocks basically has a chain structure of units derived from one kind of monomer. When the [A] block copolymer having such a plurality of blocks is dissolved in an appropriate solvent, the same type of blocks aggregate to form a phase composed of the same type of blocks. At this time, since phases formed from different types of blocks do not mix with each other, it is presumed that a phase separation structure having an ordered pattern in which different types of phases are alternately repeated can be formed.

  [A] The block copolymer may be a block copolymer having only the block of the structure (1), or may further contain other blocks in addition to the structure (1). .

  Examples of these [A] block copolymers include diblock copolymers, triblock copolymers, and tetrablock copolymers. Among these, from the viewpoint that a pattern having a desired fine microdomain structure can be easily formed, a diblock copolymer and a triblock copolymer are preferable, and a diblock copolymer is more preferable.

The formula (1), R ¹ and R ² are each independently a monovalent hydrocarbon group having a hydrogen atom or 1 to 6 carbon atoms, more preferably a hydrogen atom.

R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and an ethyl group is more preferable. R ⁴ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group, and more preferably a hydrogen atom or a methyl group.

R ⁵ is a hydroxyl group or a monovalent organic group, and examples thereof include a carboxyl group, a cyano group, and a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, and t-butyl group; ethenyl group, 2-propenyl group, Alkenyl groups such as 3-butenyl group, 4-pentenyl group, 5-hexenyl group and 7-octenyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; aryl such as phenyl group and naphthyl group Groups and the like. Among these, an alkyl group and an alkenyl group are preferable.

X is a divalent linking group and has a partial structure excluding the halogen group portion of the bifunctional initiator described later. Specifically, a group represented by —CO—C (CH ₃ ) ₂ — is preferable.

  A and b are each independently 10 to 5,000, and c is 0 to 5, preferably 0 or 1, and more preferably 0.

  A preferred specific example of the structure (1) includes a diblock structure of a styrene block and an oxazoline block. Specific examples of the styrenic block include a polystyrene block, a poly (α-methylstyrene) block, a poly (4- (7′-octenyl) styrene) block, a polyisoprene block, and the like. Among them, a polystyrene block is preferable. . The oxazoline block is preferably an alkyl oxazoline block such as an ethyl oxazoline block.

  Other blocks than the above structure (1) include, for example, poly (meth) acrylic blocks, polyvinyl acetal blocks, polyurethane blocks, polyurea blocks, polyimide blocks, polyamide blocks, epoxy blocks, and novolak types. Examples include phenol blocks and polyester blocks. [A] The proportion of other blocks in the block copolymer is preferably 10 mol% or less with respect to all structural units in the copolymer.

  [A] The block end of the block copolymer may be treated with an appropriate end treating agent as necessary. By introducing a structure having a group containing a hetero atom at at least one end of the main chain, there is an advantage that phase separation is more likely to occur.

Although it does not specifically limit as a hetero atom in group ((alpha)) containing the said hetero atom, It is at least 1 sort (s) selected from the group which consists of an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a tin atom, and a silicon atom. Are preferred, oxygen atoms, nitrogen atoms and sulfur atoms are more preferred, and oxygen atoms are still more preferred.
<[A] Synthesis method of block copolymer>
[A] As a method for synthesizing the block copolymer, for example, the following method is used.

  That is, first, an oxazoline block is polymerized by cationic ring-opening polymerization (CROP), and then a styrene block is continuously polymerized by atom transfer radical polymerization (ATRP).

  As the initiator used for the cationic ring-opening polymerization, a bifunctional polymerization initiator is preferable, and specifically, a ketone having two hydrogen atoms substituted by chlorine, bromine or iodine atoms in one molecule. A compound, an ether compound, an ester compound, etc. are mentioned. Preferable initiators include 2-bromo-2-isopropanol bromide. In addition, a Lewis acid such as sodium iodide may be added as a cocatalyst.

  The [A] block copolymer obtained by the above-described method is preferably recovered by a reprecipitation method. That is, after completion of the reaction, the target copolymer is recovered as a powder by introducing the reaction solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] The weight average molecular weight (Mw) of the block copolymer by gel permeation chromatography (GPC) is preferably 2,000 to 150,000, more preferably 3,000 to 120,000, and 4,000. More preferred is ~ 100,000. [A] By making Mw of a block copolymer into the said specific range, the said composition for pattern formation can form the pattern which has a finer micro domain structure.

  [A] The ratio (Mw / Mn) of Mw and number average molecular weight (Mn) of the block copolymer is usually 1 to 5, preferably 1 to 3, more preferably 1 to 2, and 1 to 1. .5 is more preferable, and 1 to 1.2 is particularly preferable. By making Mw / Mn into such a specific range, the pattern forming composition can form a pattern having a finer and better microdomain structure.

Mw and Mn are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, manufactured by Tosoh Corporation), flow rate 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1.0 mass%, sample Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, using a differential refractometer as a detector under the analysis conditions of an injection amount of 100 μL and a column temperature of 40 ° C.
[[B] Organic solvent]
The pattern forming composition contains an organic solvent. Examples of the organic solvent include alcohol solvents, ether solvents, ketone organic solvents, amide solvents, ester organic solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
C3-C18 alicyclic monoalcohol solvents such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as 1,2-propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of the ester solvent include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples include carbonate solvents such as dimethyl carbonate and diethyl carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

Of these, propylene glycol monomethyl ether acetate is preferred. In addition, these solvents may be used independently and may use 2 or more types together.
[Surfactant]
The pattern forming composition may further contain a surfactant. The application | coating property to a board | substrate etc. can be improved because the said composition for pattern formation contains surfactant.
<Preparation method of the pattern forming composition>
The pattern forming composition can be prepared, for example, by mixing [A] block copolymer, surfactant and the like at a predetermined ratio in the solvent.
<Pattern formation method>
The pattern forming method of the present invention comprises:
(1) A step of forming a self-assembled film having a phase separation structure on a substrate using the pattern forming composition of the present invention, and (2) a step of removing a part of the phase of the self-assembled film. It is the pattern formation method containing.

  Further, before the step (1), the method further includes (0-1) a step of forming a lower layer film on the substrate, and (0-2) a step of forming a pre-pattern on the lower layer film. ) Step, it is preferable to form a self-assembled film in the region on the lower layer film delimited by the pre-pattern, and (2 ′) the step of removing the pre-pattern after the step (1).

Further, after the step (2), it is preferable to further include (3) a step of etching the substrate using the formed pattern as a mask. Hereinafter, each process is explained in full detail. Each process will be described with reference to FIGS.
[(0-1) Step]
This step is a step of forming a lower layer film on the substrate using the lower layer film forming composition. Thereby, as shown in FIG. 1, a substrate with a lower layer film in which the lower layer film 102 is formed on the substrate 101 can be obtained, and the self-assembled film is formed on the lower layer film 102. The phase-separated structure (microdomain structure) of the self-assembled film has an interaction with the lower layer film 102 in addition to the interaction between the blocks of the [A] block copolymer contained in the pattern forming composition. Therefore, the structure control is facilitated by providing the lower layer film 102, and a desired pattern can be obtained. Further, when the self-assembled film is a thin film, the transfer process can be improved by having the lower layer film 102.

  As the substrate 101, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used.

  Moreover, conventionally well-known organic underlayer film forming material can be used as said composition for lower layer film formation.

The formation method of the lower layer film 102 is not particularly limited. For example, a coating film formed by applying a known method such as a spin coating method on the substrate 101 is cured by exposure and / or heating. can do. Examples of radiation used for this exposure include visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ-rays, molecular beams, and ion beams.
Moreover, the temperature at the time of heating a coating film is although it does not specifically limit, It is preferable that it is 90-550 degreeC, 90-450 degreeC is more preferable, and 90-300 degreeC is further more preferable. The thickness of the lower layer film 102 is not particularly limited, but is preferably 50 to 20,000 nm, and more preferably 70 to 1,000 nm. The lower layer film 102 preferably includes an SOC (Spin on carbon) film.
[(0-2) Step]
In this step, as shown in FIG. 2, a prepattern 103 is formed on the lower layer film 102 using a composition for forming a prepattern. The pattern shape obtained by the phase separation of the pattern forming composition is controlled by the pre-pattern 103, and a desired fine pattern can be formed. That is, among the blocks of the [A] block copolymer contained in the pattern forming composition, the block having high affinity with the side surface of the prepattern forms a phase along the prepattern, and the block having low affinity is A phase is formed at a position away from the pre-pattern. Thereby, a desired pattern can be formed. Moreover, the structure of the pattern obtained by the phase separation of the pattern forming composition can be finely controlled by the material, size, shape and the like of the prepattern. The pre-pattern can be appropriately selected according to the pattern to be finally formed. For example, a line and space pattern, a hole pattern, or the like can be used.

  As a method for forming the pre-pattern 103, a method similar to a known resist pattern forming method can be used. Further, as the pre-pattern forming composition, a conventional resist film-forming composition can be used. As a specific method for forming the pre-pattern 103, for example, a chemically amplified resist composition such as ARX2928JN (manufactured by JSR) is used and applied onto the lower layer film 102 to form a resist film. Next, exposure is performed by irradiating a desired region of the resist film with radiation through a mask having a specific pattern. Examples of the radiation include ultraviolet rays, far ultraviolet rays, X-rays, and charged particle beams. Among these, far ultraviolet rays represented by ArF excimer laser and KrF excimer laser are preferable, and ArF excimer laser is more preferable. Moreover, immersion exposure can also be performed as an exposure method. Next, post-exposure baking (PEB) is performed, and development is performed using a developer such as an alkali developer or an organic solvent, so that a desired pre-pattern 103 can be formed.

Note that the surface of the pre-pattern 103 may be subjected to a hydrophobic treatment or a hydrophilic treatment. As a specific treatment method, a hydrogenation treatment by exposing to hydrogen plasma for a certain period of time can be cited. By increasing the hydrophobicity or hydrophilicity of the surface of the pre-pattern 103, self-organization of the pattern forming composition can be promoted.
[(1) Process]
This step is a step of forming a self-assembled film having a phase separation structure on a substrate using the pattern forming composition. When the lower layer film and the prepattern are not used, the pattern forming composition is directly applied onto the substrate to form a coating film, and a self-assembled film having a phase separation structure is formed. When the lower layer film and the prepattern are used, as shown in FIGS. 3 and 4, the pattern forming composition is applied to a region on the lower layer film 102 sandwiched between the prepatterns 103 to apply the coating film 104. And a self-assembled film 105 having a phase separation structure having an interface substantially perpendicular to the substrate 101 is formed on the lower layer film 102 formed on the substrate 101. That is, by applying a pattern forming composition containing a block copolymer [A] having two or more incompatible blocks to each other on a substrate and performing annealing or the like, blocks having the same properties can be obtained. It is possible to promote so-called self-organization that accumulates and spontaneously forms an ordered pattern. Thereby, a self-assembled film having a phase separation structure such as a sea-island structure, a cylinder structure, a bicontinuous structure, or a lamella structure can be formed. These phase separation structures are substantially perpendicular to the substrate 101. A phase separation structure having an interface is preferable. In this step, phase separation easily occurs by using the pattern forming composition, so that a finer phase separation structure (microdomain structure) can be formed.

  In the case of having a pre-pattern, this phase separation structure is preferably formed along the pre-pattern, and the interface formed by phase separation is more preferably substantially parallel to the side surface of the pre-pattern. For example, when the affinity between the prepattern 103 and the styrene block of the [A] block copolymer is high, the phase of the styrene block is formed linearly along the prepattern 103 (105b), and the poly A lamellar phase separation structure or the like in which the phases (105a) of the methyl methacrylate block and the phases (105b) of the styrene block are alternately arranged in this order is formed. Note that the phase separation structure formed in this step is composed of a plurality of phases, and the interface formed from these phases is usually substantially vertical, but the interface itself is not necessarily clear. [A] ratio of length of each block chain (styrene block chain, polymethyl methacrylate block chain, etc.) in block copolymer molecule, [A] length of block copolymer molecule, pre-pattern, lower layer film Thus, the desired phase separation structure can be precisely controlled to obtain a desired fine pattern.

  A method for forming the coating film 104 by applying the pattern forming composition on a substrate is not particularly limited, and examples thereof include a method of applying the pattern forming composition to be used by a spin coating method or the like. Thus, the pattern forming composition is filled between the prepatterns 103 on the lower layer film 102.

Examples of the annealing method include a method of heating at a temperature of 80 ° C. to 400 ° C. with an oven, a hot plate or the like. The annealing time is usually 1 minute to 120 minutes, preferably 5 minutes to 90 minutes. The film thickness of the self-assembled film 105 thus obtained is preferably 0.1 nm to 500 nm, and more preferably 0.5 nm to 100 nm.
[(2) Process]
This step is a step of removing a part of the block phase 105a in the phase separation structure of the self-assembled film 105 as shown in FIGS.
The polymethyl methacrylate block phase 105a can be removed by an etching process using the difference in etching rate between phases separated by self-assembly. FIG. 5 shows a state after the polymethyl methacrylate block phase 105a in the phase separation structure and the pre-pattern 103 are removed as will be described later. In addition, you may irradiate a radiation before the said etching process as needed. As the radiation, when the phase to be removed by etching is a polymethyl methacrylate block phase, radiation of 254 nm can be used. Since the polymethyl methacrylate block phase is decomposed by the radiation irradiation, etching becomes easier.

As a method for removing the polymethyl methacrylate block phase 105a in the phase separation structure of the self-assembled film 105, for example, reactive ion etching (RIE) such as chemical dry etching or chemical wet etching; sputter etching, ion A known method such as physical etching such as beam etching may be used. Of these, reactive ion etching (RIE) is preferable, and among these, chemical dry etching using CF ₄ , O ₂ gas, etc., and chemical wet etching (wet type) using a liquid etching solution such as an organic solvent or hydrofluoric acid. Development) is more preferable. Examples of the organic solvent include alkanes such as n-pentane, n-hexane and n-heptane, cycloalkanes such as cyclohexane, cycloheptane and cyclooctane, ethyl acetate, n-butyl acetate, i-butyl acetate and propionic acid. Saturated carboxylic acid esters such as methyl, ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone, methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pen Examples thereof include alcohols such as tanol.
In addition, these solvents may be used independently and may use 2 or more types together.
[(2 ′) step]
This step is a step of removing the pre-pattern 103 as shown in FIGS. By removing the pre-pattern 103, a finer and more complicated pattern can be formed. As for the method of removing the pre-pattern 103, the above description of the method of removing a part of the block phases 105a in the phase separation structure can be applied. Moreover, this process may be performed simultaneously with the said (2) process, and may be performed before or after the (2) process.
[(3) Process]
This step is a step of patterning by etching the lower layer film and the substrate after the step (2), using a pattern made of the polystyrene block phase 105b, which is a part of the block phase of the remaining phase separation film, as a mask. After the patterning on the substrate is completed, the phase used as a mask is removed from the substrate by dissolution treatment or the like, and a finally patterned substrate (pattern) can be obtained. As the etching method, the same method as in step (2) can be used, and the etching gas and the etching solution can be appropriately selected depending on the material of the lower layer film and the substrate. For example, when the substrate is a silicon material, a mixed gas of chlorofluorocarbon gas and SF ₄ or the like can be used. When the substrate is a metal film, a mixed gas of BCl ₃ and Cl ₂ or the like can be used. The pattern obtained by the pattern forming method is preferably used for a semiconductor element and the like, and the semiconductor element is widely used for an LED, a solar cell, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The measuring method of each physical property value is shown below.
[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) using Tosoh GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under the following conditions.

Eluent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene <Synthesis of [A] block copolymer>
Synthesis example 1
To a 300 mL three-necked flask equipped with a condenser and a thermometer, 24 mL (237.6 mmol) of ethyloxazoline, 100 mL of acetonitrile, and 0.384 mL (1.98 mmol) of α-bromoisobutyl bromide were added, and reacted at 140 ° C. for 1 hour. It was. The resulting solution was diluted with 50 mL of chloroform, purified by precipitation into 2000 g of diethyl ether, and dried under reduced pressure to obtain 21.2 g of a white solid. The obtained polymer (A-1) was Mn: 11000 and Mw / Mn: 1.10.

Next, 0.067 g (0.467 mmol) copper (I) bromide and 0.124 mL (0.467 mmol) tris [2- (dimethylamino) ethyl] amine were added to a nitrogen-substituted 100 mL three-necked flask to prepare a metal complex. Then, 25 mL of anisole, 10.7 mL (93.4 mmol) of styrene and 1.73 g (0.467 mmol) of macroinitiator (A-1) were added and stirred for 30 minutes, and then stirred at 80 ° C. for 6 hours. The obtained polymerization solution was purified by precipitation into 2000 g of methanol and dried under reduced pressure to obtain 9.6 g of a white solid. The obtained block copolymer (B-1) was Mn: 22000, Mw / Mn: 1.18.
<Preparation of pattern forming composition>
The obtained block copolymer (B-1) was dissolved in propylene glycol monomethyl ether acetate (PGMEA) to give a 1.5% by mass solution. This solution was filtered through a membrane filter having a pore size of 200 nm to prepare a self-assembling composition for pattern formation (C-1).
<Pattern formation method>
After applying the pattern forming composition so that the film thickness of the self-assembled film formed on the silicon wafer substrate is 40 nm, it is heated at 250 ° C. for 10 minutes to cause phase separation, and a fingerprint having a microdomain structure is formed. Formed. The fingerprint pattern was observed using a scanning electron microscope (“S-4800” manufactured by Hitachi, Ltd.).

  According to the present invention, it is possible to provide a pattern forming composition capable of forming a pattern having a sufficiently fine microdomain structure and a pattern forming method using the same. Therefore, the composition for pattern formation, the pattern formation method, and the block copolymer of the present invention are suitably used in lithography processes in the production of various electronic devices such as semiconductor devices and liquid crystal devices that are required to be further miniaturized.

101. Substrate 102. Underlayer film 103. Pre-pattern 104. Coating film 105. Self-assembled film 105a. Polyoxazoline block phase 105b. Polystyrene block phase

Claims (3)

[A] A pattern forming composition comprising a block copolymer having a structure represented by the following formula (1), and [B] an organic solvent.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ³ is a monovalent carbon atom having 1 to 6 carbon atoms. A hydrogen group, R ⁴ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group, R ⁵ is a hydroxyl group or a monovalent organic group, X is a divalent linking group, a and b is 10-5000 each independently, and c is 0-5.) (1) a step of forming a self-assembled film having a phase separation structure on the substrate surface using the pattern forming composition according to claim 1; and (2) a part of the phase of the self-assembled film. The pattern formation method including the process of removing. A block copolymer having a structure represented by the following formula (1).

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ³ is a monovalent carbon atom having 1 to 6 carbon atoms. A hydrogen group, R ⁴ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group, R ⁵ is a hydroxyl group or a monovalent organic group, X is a divalent linking group, a and b is 10-5000 each independently, and c is 0-5.)