JP7126338B2 - Method for producing resin and method for producing structure containing phase separation structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a resin and a method for producing a structure having a phase separation structure.

In the lithography technique, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light and developed to form a resist pattern having a predetermined shape on the resist film. A forming step is performed. A resist material in which the exposed portion of the resist film becomes soluble in the developer is called a positive type, and a resist material in which the exposed portion of the resist film becomes insoluble in the developer is called a negative type.
2. Description of the Related Art In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, advances in lithography technology have led to rapid miniaturization of patterns. As a technique for pattern miniaturization, generally, the wavelength of the exposure light source is shortened (the energy is increased). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, semiconductor devices using KrF excimer lasers and ArF excimer lasers are being mass-produced. In addition, EUV (extreme ultraviolet rays), EB (electron beam), X-rays, etc., which have a shorter wavelength (higher energy) than these excimer lasers, are also being studied.
Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions.
Conventionally, as a resist material satisfying such requirements, a chemically amplified resist composition containing a base component whose solubility in a developing solution is changed by the action of an acid and an acid generator component which generates an acid upon exposure. is used.

As patterns become finer and finer, resist materials are required to improve various lithography properties and suppress the occurrence of defects (surface defects).
The term "defect" as used herein refers to defects in general that are detected when the resist pattern after development is observed from directly above, for example, using a surface defect observation device (trade name: "KLA") manufactured by KLA-Tencor. . These defects include, for example, scum (resist residue) after development, bubbles, dust, and other foreign matter and deposits adhering to the resist pattern surface, bridging between line patterns, and filling of contact hole pattern holes. Defects related to the pattern shape such as, uneven color of the pattern, etc.

In addition, in the resist material, fine particle-like foreign matter is generated during storage of the resist solution (resist composition in solution state), and the aging property of foreign matter (one of storage stability) is also a problem, and improvement is made. is desired.

Conventionally, in the production of resist compositions, purification is generally carried out by passing through a filter in order to remove foreign matter. However, the method of passing a resist composition through a conventionally used membrane filter or depth filter is insufficient to suppress the occurrence of defects in a resist pattern after development.
In order to suppress the occurrence of defects in the resist pattern and to meet the requirements for foreign matter aging characteristics of the resist material, the resist material has both a step of passing through a nylon filter and a step of passing through a polyolefin resin or fluororesin filter. A method for producing a resist composition has been proposed (see Patent Document 1).

Japanese Patent No. 4637476

As lithography technology progresses further and resist patterns become finer and finer, problems such as scum and microbridges after development become a significant problem when forming resist patterns of several tens to several hundreds of nanometers in size. Therefore, more than ever before, there is a need for a technique capable of suppressing the occurrence of defects in a resist pattern after development.

In addition, as large-scale integrated circuits (LSIs) are further miniaturized, there is a demand for techniques for processing more delicate structures. In response to such demands, technology development is being carried out to form a finer structure using a phase separation structure formed by self-organization of block copolymers in which mutually incompatible blocks are bonded together. .
In order to utilize the phase separation of block copolymers, it is essential to form self-assembled nanostructures formed by microphase separation only in specific regions and to align them in desired directions. In the phase separation of such block copolymers, the influence of impurities present together with the block copolymer becomes a problem.

The present invention has been made in view of the above circumstances, and provides a method for producing a resin that can further reduce impurities, and a structure containing a phase separation structure that can further enhance the phase separation performance of a block copolymer. To provide a manufacturing method of

The inventors of the present invention have investigated and found that when purifying a resin composition containing a polymer consisting of a repeating structure of hydrophobic structural units, by filtering with a specific filter selected, the polymer can be highly purified. The present inventors have found that the method can be made more efficient, and have completed the present invention.

In a first aspect of the present invention, a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1) is filtered through a filter equipped with a polyolefin resin membrane to obtain a purified resin. A method for producing a resin, characterized by having a filtration step to obtain.

In a second aspect of the present invention, a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1) is filtered through a filter equipped with a polyolefin resin membrane to obtain a purified resin. a step of applying a primer containing the purified resin onto a substrate to form a primer layer; and a block in which a hydrophobic polymer block and a hydrophilic polymer block are bonded on the primer layer. A method for producing a structure having a phase-separated structure, comprising the steps of: forming a layer containing a copolymer; and phase-separating the layer containing the block copolymer.

According to the method for producing a resin according to the present invention, a resin with reduced impurities can be produced.
According to the method for producing a structure containing a phase separation structure according to the present invention, the phase separation performance of block copolymers can be further enhanced.

It is a schematic process drawing explaining one embodiment of the manufacturing method of the structure containing a phase-separation structure. FIG. 10 is a diagram illustrating an example embodiment of an optional step;

In the present specification and claims, "aliphatic" is defined relative to aromatic to mean groups, compounds, etc. that do not possess aromatic character.
"Alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
Unless otherwise specified, the "alkylene group" includes straight-chain, branched-chain and cyclic divalent saturated hydrocarbon groups.
A "halogenated alkyl group" is a group in which some or all of the hydrogen atoms of an alkyl group are substituted with halogen atoms, and the halogen atoms include fluorine, chlorine, bromine and iodine atoms.
A "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which some or all of the hydrogen atoms of an alkyl group or alkylene group have been substituted with fluorine atoms.
A "structural unit" means a monomer unit (monomeric unit) that constitutes a polymer compound (resin, polymer, copolymer).
“Exposure” is a concept that includes irradiation of radiation in general.

(Resin manufacturing method)
In the method for producing a resin of the present embodiment, a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1) is filtered through a filter equipped with a polyolefin resin membrane to obtain a purified resin. It has a filtration step to obtain

<Resin composition>
The resin composition in the present embodiment contains a polymer having a repeating structure of hydrophobic structural units (u1). Such resin compositions may be solutions, dispersions, and the like.

≪Polymer≫
The polymer (hereinafter also referred to as "polymer (P)" or "(P) component") in the present embodiment consists of a repeating structure of hydrophobic structural units (u1).
Such a polymer (P) is not particularly limited, and may be either a copolymer consisting of a repeating structure of two or more structural units (u1) or a homopolymer consisting of a repeating structure of one structural unit (u1). good.

A “hydrophobic structural unit” refers to a structural unit derived from a monomer that has low affinity for water (that is, it is difficult to dissolve or mix with water).

・Constituent unit (u1)
For the hydrophobic structural unit (u1), for example, a structural unit containing a styrene skeleton which may have a substituent is preferably used.
Structural units containing a styrene skeleton which may have a substituent include structural units derived from styrene and structural units derived from styrene derivatives.

Styrene derivatives include, for example, those in which the α-position hydrogen atom of styrene is substituted with an alkyl group or a halogenated alkyl group, or derivatives thereof. Examples of these derivatives include those in which a substituent is bonded to the benzene ring of styrene in which the α-position hydrogen atom may be substituted with a substituent. Examples of the substituents bonded to the benzene ring include alkyl groups having 1 to 5 carbon atoms, halogenated alkyl groups having 1 to 5 carbon atoms, and hydroxyalkyl groups. The α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.

The alkyl group as the α-position substituent is preferably a linear or branched alkyl group, and specifically, an alkyl group having 1 to 5 carbon atoms (e.g., methyl group, ethyl group, n-propyl group , isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group) and the like.
Examples of the halogenated alkyl group as the α-position substituent include groups obtained by substituting some or all of the hydrogen atoms of the above “alkyl group as the α-position substituent” with halogen atoms. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being particularly preferred.
Examples of the hydroxyalkyl group as the α-position substituent include groups obtained by substituting some or all of the hydrogen atoms of the above “alkyl group as the α-position substituent” with hydroxyl groups. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, more preferably 1.

Specific examples of styrene derivatives include α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, and 2,4,6-trimethylstyrene. , 4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene, 4-vinylbenzyl chloride, etc. are mentioned.

Among the structural units (u1), a structural unit derived from styrene (structural unit (u11)), a structural unit derived from a monomer in which the α-position hydrogen atom of styrene is substituted with an alkyl group having 1 to 5 carbon atoms. (Structural unit (u12)), a structural unit (structural unit ( u13)) is preferable, and a structural unit derived from styrene (structural unit (u11)) is more preferable.

As the polymer (P) in the present embodiment, for example, a polymer having a structural unit (u11) is preferable.
Specific examples of the polymer (P) include a homopolymer (homopolymer) consisting of a repeating structure of the structural unit (u11); a copolymer having a structural unit (u11) and a structural unit (u12); A copolymer having (u11) and the structural unit (u13), and a copolymer having the structural unit (u11), the structural unit (u12) and the structural unit (u13) can be mentioned.
In the polymer (P), the structural unit (u11) is preferably 50 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% of all the structural units constituting the component (P). Those having the above are preferably used. Among them, as the component (P), a homopolymer consisting of a repeating structure of the structural unit (u11) is particularly preferable.

The mass-average molecular weight (Mw) of component (P) (polystyrene equivalent by gel permeation chromatography) is preferably 1,000 to 200,000, more preferably 1,500 to 200,000, and still more preferably 2,000 to 150,000.
The molecular weight dispersity (Mw/Mn) of component (P) is preferably 1.0 to 5.0, more preferably 1.0 to 4.5, still more preferably 1.0 to 3.0. In addition, Mn shows a number average molecular weight.

<<Solvent or dispersion medium>>
The resin composition in this embodiment can be prepared by mixing the (P) component with a solvent or a dispersion medium.
For the solvent or dispersion medium, for example, water or an organic solvent component is used.
Examples of the organic solvent component include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone and 2-heptanone; ethylene glycol, diethylene glycol and propylene glycol. , polyhydric alcohols such as dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, the polyhydric alcohols or the ester bond Derivatives of polyhydric alcohols such as compounds having an ether bond such as monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, etc. of compounds or monophenyl ethers [among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether preferred]; cyclic ethers such as dioxane; methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxy Esters such as ethyl propionate; anisole, ethylbenzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Aromatic organic solvent; dimethyl sulfoxide and the like.
The solvent or dispersion medium may be used singly or as a mixed solvent of two or more.
From the viewpoint of compatibility with the polymer (P), it is preferable to use an organic solvent component as the solvent or dispersion medium, and it is particularly preferable to use PGMEA.

≪Other ingredients≫
The resin composition in the present embodiment may contain other components, if necessary, in addition to the polymer (P), solvent or dispersion medium.

The concentration of the polymer (P) in the resin composition in the present embodiment is preferably 0.1 to 20% by mass, more preferably 0.2 to 15% with respect to the total amount (100% by mass) of the resin composition. % by mass, more preferably 0.2 to 10% by mass.

<Filter with membrane made of polyolefin resin>
A filter used in the filtration step is equipped with a membrane made of polyolefin resin. Examples of polyolefin resins used herein include polyethylene resins, polypropylene resins, and mixtures thereof. The density and molecular weight of the polyolefin resin may be appropriately determined according to the resin composition to be removed.
As such a filter, a filter provided with a polyethylene membrane (polyethylene filter) is preferably used.
The filtration accuracy (particle diameter to be removed) of such a filter is, for example, 200 nm or less, preferably 100 nm or less, more preferably 50 nm or less.

[Filtration step: Filtration of resin composition]
In the filtration step, the resin composition is passed through a filter provided with a membrane made of polyolefin resin. Foreign substances and the like are removed from the resin composition by such an operation.
Such an operation may be performed without a differential pressure (that is, the resin composition may be passed through the filter only by gravity) or may be performed with a differential pressure.

"A state in which a differential pressure is provided" means that there is a pressure differential between one side and the other side of the polyolefin resin membrane provided in the filter.
For example, a pressurized (positive pressure) state in which pressure is applied to one side (resin composition supply side) of the polyolefin resin membrane, and a reduced pressure state in which one side (filtrate side) of the polyolefin resin membrane is negative pressure ( negative pressure) state.

In the present embodiment, it is preferable to perform the operation in the filtration step under the above-described pressurized (positive pressure) state. In order to perform this operation under pressure (positive pressure), an inert or non-reactive gas may be used.

After the operation of passing the resin composition through a filter, the filtrate is dried to obtain a purified resin.

In the resin production method of the present embodiment described above, when purifying a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1), a specific filter (made of polyolefin resin) A filter with a membrane) is employed to perform the filtration. Therefore, it is possible to efficiently remove various foreign matter and produce a high-purity resin.
The effect of this embodiment is that a resin composition containing a copolymer having a hydrophobic structural unit (u1) and a hydrophilic structural unit having a relatively high affinity for water compared to this When purifying , it appears more markedly than when filtration is performed using a filter equipped with a membrane made of polyolefin resin.
In addition, the effect of this embodiment is obtained when a filter equipped with a membrane made of a resin different from that made of a polyolefin resin is used when purifying a resin composition containing a polymer (P). appears more prominently than

(Manufacturing method of structure including phase separation structure)
In the method for producing a structure containing a phase-separated structure of the present embodiment, a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1) is filtered through a filter equipped with a polyolefin resin membrane. and obtaining a purified resin (hereinafter referred to as "step (i)"); and a step of applying a base material containing the purified resin onto a substrate to form a base material layer (hereinafter referred to as "step (ii) )”), forming a layer containing a block copolymer in which a hydrophobic polymer block and a hydrophilic polymer block are combined on the undercoat layer (hereinafter referred to as “step (iii)”); and a step of phase-separating the layer containing the block copolymer of (hereinafter referred to as “step (iv)”).
Hereinafter, a method for manufacturing a structure including such a phase separation structure will be specifically described with reference to FIG. However, the present invention is not limited to this.

FIG. 1 shows this embodiment of a method for manufacturing a structure containing a phase separation structure.
First, a base layer 2 is formed by applying a base layer 2 containing the purified resin obtained in the filtering step described above onto the substrate 1 (FIG. 1(I); step (ii)).
Next, a composition containing a block copolymer in which a hydrophobic polymer block and a hydrophilic polymer block are combined (hereinafter also referred to as "BCP composition") is applied onto the undercoat layer 2, and the block copolymer is coated. forming a layer 3 containing (FIG. 1(II); step (iii));
Next, the layer 3 containing the block copolymer is subjected to an annealing treatment by heating to phase-separate into a phase 3a and a phase 3b (FIG. 1(III); step (iv)).
As described above, a structure 3' including a phase separation structure is manufactured on the substrate 1 on which the base material layer 2 is formed.

<Step (i)>
In step (i), a resin composition containing a polymer having a repeating structure of hydrophobic structural units (u1) is filtered through a filter equipped with a polyolefin resin membrane to obtain a purified resin.
The explanation of this step (i) is the same as the explanation of the filtering step and the like in the above-described (resin production method).

<Step (ii)>
In step (ii), a base layer 2 is formed by applying a base layer 2 containing the purified resin onto the substrate 1 .
By providing the underlayer 2 on the substrate 1, the surface of the substrate 1 is made hydrophobic. As a result, of the block copolymer-containing layer 3 formed on the base material layer 2 , the hydrophobic block phase having a high affinity with the substrate 1 has increased adhesion to the substrate 1 . Along with this, the phase separation of the layer 3 containing the block copolymer facilitates the formation of a cylindrical structure oriented in the direction perpendicular to the surface of the substrate 1 .

The type of the substrate 1 is not particularly limited as long as the surface of the substrate 1 can be coated with the BCP composition. For example, metals (silicon, copper, chromium, iron, aluminum, etc.), glass, titanium oxide, silicon dioxide (SiO ₂ ), silica, substrates made of inorganic substances such as mica; substrates made of nitrides such as SiN; substrates made of nitrides such as SiN; Substrates made of nitrides; and substrates made of organic substances such as acrylic, polystyrene, cellulose, cellulose acetate, and phenolic resin. Among these, metal substrates are suitable, for example silicon substrates (Si substrates), silicon dioxide substrates (SiO ₂ substrates) or copper substrates (Cu substrates), on which cylindrical structures are formed. Among them, it is particularly suitable for Si substrates and _SiO2 substrates.
The size and shape of the substrate 1 are not particularly limited. The substrate 1 does not necessarily have a smooth surface, and substrates having various shapes can be selected as appropriate. Examples thereof include a substrate having a curved surface, a flat plate having an uneven surface, and a substrate having a flaky shape.

An inorganic and/or organic film may be provided on the surface of the substrate 1 .
Inorganic films include inorganic antireflection coatings (inorganic BARC). Organic films include organic antireflection coatings (organic BARC).
The inorganic film can be formed, for example, by applying an inorganic antireflection film composition such as a silicon-based material onto a substrate and baking the composition.
For the organic film, for example, an organic film-forming material obtained by dissolving a resin component or the like constituting the film in an organic solvent is applied onto a substrate with a spinner or the like, and the temperature is preferably 200 to 300° C., preferably 30 to 300° C. It can be formed by baking under heating conditions of 60 to 180 seconds, preferably 60 to 180 seconds. This organic film-forming material does not necessarily require sensitivity to light or electron beams like a resist film, and may or may not have sensitivity. Specifically, resists and resins commonly used in the manufacture of semiconductor elements and liquid crystal display elements can be used.
The organic film-forming material is preferably a material capable of forming an organic film that can be etched, particularly dry-etched. With such an organic film-forming material, by etching the organic film using a block copolymer pattern formed by processing the layer 3, the pattern is transferred to the organic film. and an organic film pattern can be formed. Among them, a material capable of forming an organic film that can be etched by oxygen plasma etching or the like is preferable. Such an organic film-forming material may be a material conventionally used for forming an organic film such as an organic BARC. Examples thereof include the ARC series manufactured by Nissan Chemical Industries, Ltd., the AR series manufactured by Rohm and Haas, and the SWK series manufactured by Tokyo Ohka Kogyo Co., Ltd.

The method of forming the underlayer 2 by coating the undercoat on the substrate 1 is not particularly limited, and can be formed by a conventionally known method.
For example, the undercoat layer 2 can be formed by coating the undercoat on the substrate 1 by a conventionally known method such as spin coating or using a spinner to form a coating film, followed by drying.
As a method for drying the coating film, it is sufficient that the solvent contained in the undercoating agent can be volatilized, and examples thereof include a baking method and the like. At this time, the baking temperature is preferably 80 to 300.degree. Baking time is preferably 30 to 500 seconds, more preferably 60 to 400 seconds.
The thickness of the underlayer 2 after drying the coating film is preferably about 10 to 100 nm, more preferably about 40 to 90 nm.

Before forming the base material layer 2 on the substrate 1, the surface of the substrate 1 may be washed in advance. By cleaning the surface of the substrate 1, the coatability of the base material is improved.
Conventionally known methods can be used as the cleaning treatment method, and examples thereof include oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.

After forming the undercoat layer 2, the undercoat layer 2 may be rinsed with a rinse liquid such as a solvent, if necessary. Since the rinsing removes uncrosslinked portions and the like in the undercoat layer 2, the affinity with at least one polymer (block) constituting the block copolymer is improved, and the polymer is oriented in the direction perpendicular to the surface of the substrate 1. A phase-separated structure consisting of a cylindrical structure formed by the
Any rinsing solution may be used as long as it can dissolve the uncrosslinked portions, and solvents such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether, and ethyl lactate, or commercially available thinner solutions can be used. .
After the cleaning, post-baking may be performed to volatilize the rinsing liquid. The temperature condition for this post-baking is preferably 80 to 300.degree. Baking time is preferably 30 to 500 seconds, more preferably 60 to 240 seconds. The thickness of the undercoat layer 2 after post-baking is preferably about 1 to 50 nm, more preferably about 2 to 40 nm.

<Step (iii)>
In step (iii), a layer 3 containing a block copolymer in which hydrophobic polymer blocks and hydrophilic polymer blocks are combined is formed on the undercoat layer 2 .
The method for forming the layer 3 on the undercoat layer 2 is not particularly limited. to form a coating film and then dry it. Details of such a BCP composition will be described later.

The thickness of the layer 3 may be a thickness sufficient for phase separation to occur. , preferably 20 to 100 nm, more preferably 30 to 80 nm.
For example, if the substrate 1 is a Si substrate or a SiO ₂ substrate, the thickness of the layer 3 is preferably 20-100 nm, more preferably 30-80 nm.
When the substrate 1 is a Cu substrate, the thickness of the layer 3 is preferably 10-100 nm, more preferably 30-80 nm.

<Step (iv)>
In step (iv), the layer 3 containing the block copolymer is phase separated.
By selectively removing the block copolymer by heating and annealing the substrate 1 after step (iii), a phase-separated structure is formed in which at least part of the surface of the substrate 1 is exposed. That is, on the substrate 1, a structure 3' including a phase-separated structure, which is phase-separated into phases 3a and 3b, is manufactured.
The temperature conditions for the annealing treatment are preferably higher than the glass transition temperature of the block copolymer used and lower than the thermal decomposition temperature. For example, when the block copolymer is a polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer (mass average molecular weight 5000-100000), the temperature is preferably 180-270°C. The heating time is preferably 30 to 3600 seconds.
Also, the annealing treatment is preferably performed in a gas with low reactivity such as nitrogen.

In the method for producing a structure including a phase-separated structure according to the present embodiment described above, the resin in which impurities are further reduced and which is produced by the above-described (method for producing a resin) is used for the base material layer. . Therefore, the phase separation performance of the block copolymer can be further enhanced. In addition, finer structures can be formed with better shapes than existing lithography techniques. In addition, it is possible to manufacture a substrate having nanostructures with more freely designed positions and orientations on the surface of the substrate. For example, the formed structure has high adhesion to the substrate and tends to have a phase-separated structure consisting of a cylindrical structure oriented in the direction perpendicular to the substrate surface.

[Optional process]
The method for manufacturing a structure containing a phase separation structure according to the present invention is not limited to the above-described embodiments, and may further include steps (optional steps) other than steps (i) to (iv).
As such an optional step, a step of selectively removing a phase composed of at least one type of block among hydrophobic polymer blocks and hydrophilic polymer blocks constituting the block copolymer from the layer containing the block copolymer (hereinafter referred to as (referred to as “step (v)”), guide pattern forming step, and the like.

- Regarding step (v) In step (v), in the layer containing the block copolymer formed on the base layer, at least a hydrophobic polymer block and a hydrophilic polymer block constituting the block copolymer A phase consisting of one type of block is selectively removed. As a result, a fine pattern (polymer nanostructure) is formed.

Methods for selectively removing the block phase include a method of subjecting the layer containing the block copolymer to oxygen plasma treatment, a method of subjecting the layer to hydrogen plasma treatment, and the like.
In the following description, of the blocks constituting the block copolymer, the blocks that are not selectively removed are referred to as _PA blocks, and the blocks that are selectively removed are referred to as _PB blocks. For example, after phase-separating a layer containing a PS-PMMA block copolymer, the layer is subjected to oxygen plasma treatment, hydrogen plasma treatment, or the like to selectively remove the PMMA phase. In this case, the PS part is the _PA block and the PMMA part is the _PB block.

FIG. 2 shows an example embodiment of step (v).
In the embodiment shown in FIG. 2, the structure 3′ produced on the substrate 1 in step (iv) is subjected to an oxygen plasma treatment to selectively remove phase 3a from the spaced apart phase 3b. A pattern (polymer nanostructure) is formed. In this case, phase 3b is a phase consisting of _PA blocks and phase 3a is a phase consisting of _PB blocks.

The substrate 1 on which the pattern is formed by the phase separation of the block copolymer layer 3 as described above can be used as it is. ) can also be changed.
The temperature conditions for heating are preferably higher than the glass transition temperature of the block copolymer used and lower than the thermal decomposition temperature. Also, the heating is preferably performed in a gas with low reactivity such as nitrogen.

About the Guide Pattern Forming Step In the method for manufacturing a structure including a phase-separated structure according to the present invention, the step of forming a guide pattern on the base material layer (guide pattern formation step). This makes it possible to control the arrangement structure of the phase separation structure.
For example, even with a block copolymer that forms a random fingerprint-like phase separation structure when no guide pattern is provided, by providing a groove structure of the resist film on the surface of the undercoat layer, orientation along the groove can be achieved. A phase-separated structure is obtained. A guide pattern may be provided on the base material layer 2 based on such a principle. In addition, when the surface of the guide pattern has an affinity for any polymer that constitutes the block copolymer, it becomes easier to form a phase-separated structure consisting of a cylindrical structure oriented in the direction perpendicular to the substrate surface.

The guide pattern can be formed using, for example, a resist composition.
The resist composition for forming the guide pattern is appropriately selected from among resist compositions generally used for forming resist patterns and modifications thereof that have an affinity with any polymer that constitutes the block copolymer. can be used The resist composition includes a positive resist composition that forms a positive pattern in which the exposed portion of the resist film is dissolved and removed, and a negative resist composition that forms a negative pattern in which the unexposed portion of the resist film is dissolved and removed. Any of them may be used, but a negative resist composition is preferable. The negative resist composition contains, for example, an acid generator component and a base component whose solubility in a developer containing an organic solvent is reduced by the action of an acid. A resist composition containing a resin component having structural units that decompose upon action to increase polarity is preferred.
After the BCP composition is poured onto the undercoating agent layer on which the guide pattern is formed, an annealing treatment is performed to induce phase separation. Therefore, it is preferable that the resist composition for forming the guide pattern is capable of forming a resist film having excellent solvent resistance and heat resistance.

... Composition Containing Block Copolymer (BCP Composition) Examples of the BCP composition include those obtained by dissolving a block copolymer in an organic solvent component.

. . . Block Copolymer A block copolymer is a polymer compound in which a plurality of partial components (blocks) in which the same type of structural units are repeatedly bonded are bonded.
The number of types of blocks constituting the block copolymer may be two, or three or more.
The plurality of types of blocks that constitute the block copolymer are not particularly limited as long as they are a combination that causes phase separation.

Preferred block copolymers include, for example, a polymer compound (BCP-1) in which a hydrophobic polymer block (b11) and a hydrophilic polymer block (b21) are linked.
Hydrophobic polymer block (b11) (hereinafter also simply referred to as “block (b11)”) uses a plurality of monomers having relatively different affinities with water. It refers to a block composed of a polymer (hydrophobic polymer) in which a monomer with relatively low affinity is polymerized. The hydrophilic polymer block (b21) (hereinafter also simply referred to as “block (b21)”) is a polymer (hydrophilic polymer).

Block (b11) and block (b21) are not particularly limited as long as they are a combination that causes phase separation, but a combination of blocks that are incompatible with each other is preferable.
Further, the block (b11) and the block (b21) are such that the phase consisting of at least one type of block among the plurality of types of blocks constituting the block copolymer can be removed more easily than the phase consisting of the other types of blocks. A combination is preferred.
Incidentally, the polymer compound (BCP-1) may be bound with partial constituent components (blocks) other than the block (b11) and the block (b21).

As the block (b11) and the block (b21), for example, a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded, and a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. A block in which a structural unit derived from an acrylate ester (a structural unit derived from an (α-substituted) acrylate ester) is repeatedly bonded, and the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. A block in which a structural unit derived from acrylic acid (a structural unit derived from (α-substituted) acrylic acid) is repeatedly bonded, a block in which a structural unit derived from siloxane or a derivative thereof is repeatedly bonded, and a block derived from alkylene oxide Blocks in which structural units are repeatedly bonded, blocks in which silsesquioxane structure-containing structural units are repeatedly bonded, and the like are included.

As the polymer compound (BCP-1), for example, a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded, a block in which structural units derived from an (α-substituted) acrylic acid ester are repeatedly bonded, A polymer compound in which a block in which a structural unit derived from styrene or a styrene derivative is repeatedly bonded and a block in which a structural unit derived from (α-substituted) acrylic acid is repeatedly bonded are bonded; A polymer compound in which a block in which a structural unit derived from styrene or a styrene derivative is repeatedly bonded to a block in which a structural unit derived from siloxane or a derivative thereof is repeatedly bonded; a structural unit derived from an alkylene oxide A polymer compound in which a repeatedly bonded block and a block in which a structural unit derived from an (α-substituted) acrylic acid ester is repeatedly bonded; a block in which a structural unit derived from an alkylene oxide is repeatedly bonded; Substituted) polymer compound in which a block repeatedly bonded with structural units derived from acrylic acid; A polymer compound in which a block in which a constituent unit is repeatedly bound and a block in which a constituent unit containing a cage-type silsesquioxane structure is repeatedly bound and a constituent unit derived from (α-substituted) acrylic acid are repeatedly bound A polymer compound in which a block containing a cage-type silsesquioxane structure is repeatedly bonded to a block in which a structural unit derived from siloxane or a derivative thereof is repeatedly bonded. compounds and the like.

Among the above, as the polymer compound (BCP-1), a block in which a structural unit derived from styrene or a styrene derivative is repeatedly bonded, and a block in which a structural unit derived from an (α-substituted) acrylic acid ester is repeatedly bonded A polymer compound in which and is bonded; A polymer in which a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded and a block in which structural units derived from (α-substituted) acrylic acid are repeatedly bonded are bonded A compound is preferable, and a polymer compound in which a block in which a structural unit derived from styrene or a styrene derivative is repeatedly bonded and a block in which a structural unit derived from an (α-substituted) acrylic ester is repeatedly bonded are more preferable. Further preferred is a polymer compound in which a block in which a structural unit derived from styrene or a styrene derivative is repeatedly bonded and a block in which a structural unit derived from a (meth)acrylic acid ester is repeatedly bonded are bonded.
Specifically, polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer, polystyrene-polyethyl methacrylate block copolymer, polystyrene-(poly-t-butyl methacrylate) block copolymer, polystyrene-polymethacrylic acid block copolymer, polystyrene-poly Examples include methyl acrylate block copolymers, polystyrene-polyethyl acrylate block copolymers, polystyrene-(poly-t-butyl acrylate) block copolymers, polystyrene-polyacrylic acid block copolymers, and the like. Among these, PS-PMMA block copolymers are particularly preferred.

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of each polymer constituting the block copolymer is not particularly limited as long as it is a size capable of causing phase separation, but is 5000. ~500,000 is preferred, 5000 to 400,000 is more preferred, and 5000 to 300,000 is even more preferred.

The Mw of the block copolymer is not particularly limited as long as it is a size capable of causing phase separation, but is preferably 5,000 to 100,000, more preferably 20,000 to 60,000, and even more preferably 30,000 to 50,000.
The Mw/Mn of the block copolymer is preferably 1.0 to 3.0, more preferably 1.0 to 1.5, even more preferably 1.0 to 1.2.
The period of the block copolymer (the length of one molecule of the block copolymer) is preferably 5 to 50 nm, more preferably 10 to 40 nm, even more preferably 20 to 30 nm.

...Organic Solvent Component The BCP composition can be prepared by dissolving the above block copolymer in an organic solvent component. Examples of the organic solvent component include the same organic solvent components that can be used in the resin composition.
The organic solvent component contained in the BCP composition is not particularly limited, and is appropriately set according to the coating film thickness at a concentration that can be applied, and generally the solid content concentration of the block copolymer is 0.2 to It is used within the range of 70% by mass, preferably 0.2 to 50% by mass.

In addition to the block copolymer and organic solvent components described above, the BCP composition may also optionally contain miscible additives such as additional resins to improve the performance of the primer layer, Surfactants, dissolution inhibitors, plasticizers, stabilizers, coloring agents, antihalation agents, dyes, sensitizers, base multipliers, basic compounds and the like can be contained as appropriate.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

<Preparation of resin composition>
Each component shown in Table 1 was mixed to prepare a resin composition (polymer concentration: 1.5% by mass).

In Table 1, each abbreviation has the following meaning. The numbers in [ ] are the compounding amounts (parts by mass).
(P)-1: A copolymer represented by the following chemical formula (P)-1. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 40000, and the molecular weight dispersity (Mw/Mn) was 1.8. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz_ ¹³ C-NMR) is u1/u21/u22=82/12/6. there were.

(P)-2: A copolymer represented by the following chemical formula (P)-2. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 40000, and the molecular weight dispersity (Mw/Mn) was 1.8. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz_ ¹³ C-NMR) was u1/u22=97/3.

(P)-3: A homopolymer represented by the following chemical formula (P)-3. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 37000, and the molecular weight dispersity (Mw/Mn) was 1.2. The proportion (molar ratio) of structural units in the structural formula was u1=100.

(S)-1: Propylene glycol monomethyl ether acetate.

<Filter>
As filters, filters (1) to (3) shown below were used.
Filter (1): A filter with a porous membrane made of polyethylene (HDPE) resin. Part no. PHD12XG2EH11B, filtration accuracy 2 nm.
Filter (2): A filter with a porous membrane made of polyamide resin (Nylon 6,6). Part no. PHD12HXN5EH11, filtration accuracy 5 nm.
Filter (3): A filter provided with a porous membrane made of polytetrafluoroethylene (PTFE) resin. Part no. PHF12UCF10EH11-RD, filtration accuracy 10 nm.

<Resin manufacturing method>
(Example 1, Comparative Examples 1 to 8)
The above resin compositions (1) to (3) were filtered through filters (1) to (3) under the following [filtration conditions], and the filtrates were dried to obtain purified resins.
[Filtration conditions]
Filter while pressurizing with nitrogen gas. Temperature 23°C, filtering once.

(Comparative example 1)
Filtration process:
The above resin composition (1) was filtered through the filter (1) under the above [filtration conditions], and the filtrate was dried to obtain a purified resin.

(Comparative example 2)
A purified resin was obtained in the same manner as in Comparative Example 1, except that the resin composition (1) was changed to the resin composition (2).

(Example 1)
A purified resin was obtained in the same manner as in Comparative Example 1, except that the resin composition (1) was changed to the resin composition (3).

(Comparative Example 3)
Filtration process:
A purified resin was obtained in the same manner as in Comparative Example 1, except that the filter (1) was changed to the filter (2).

(Comparative Example 4)
A purified resin was obtained in the same manner as in Comparative Example 3, except that the resin composition (1) was changed to the resin composition (2).

(Comparative Example 5)
A purified resin was obtained in the same manner as in Comparative Example 3, except that the resin composition (1) was changed to the resin composition (3).

(Comparative Example 6)
Filtration process:
A purified resin was obtained in the same manner as in Comparative Example 1, except that the filter (1) was changed to the filter (3).

(Comparative Example 7)
A purified resin was obtained in the same manner as in Comparative Example 6, except that the resin composition (1) was changed to the resin composition (2).

(Comparative Example 8)
A purified resin was obtained in the same manner as in Comparative Example 6, except that the resin composition (1) was changed to the resin composition (3).

[Evaluation of Resin]
Defects were evaluated in the following manner for the resin produced by the production method of each example.
On a 12-inch silicon wafer, the liquid that has passed through the filter in the filtration step in each example described above is applied by spin coating (1500 rpm), and baked on a hot plate at 80 ° C. for 60 seconds. A resin film with a film thickness of 85 nm was formed.
Then, it was rinsed with a solvent (OK73, manufactured by Tokyo Ohka Kogyo Co., Ltd.) and dried by shaking off. After that, baking treatment was performed at 80° C. for 60 seconds to finally form a resin film with a film thickness of 40 nm.

Evaluation of defects (number of defects):
The total number of defects in the wafer (total number of defects/number of defects) was measured using a surface defect observation device (manufactured by KLA-Tencor, product name: KLA2371) for the finally obtained resin film (thickness: 40 nm). The results are shown in Table 2.

From the results shown in Table 2, it can be confirmed that the resin composition (3) (containing the homopolymer) in Example 1 using the filter (1) has the smallest number of total defects.
For the resin composition (1) (containing the copolymer), it can be confirmed that the total number of defects is the lowest in the case of Comparative Example 3 using the filter (2) instead of the filter (1).
As for the resin composition (2) (containing the copolymer), it can be confirmed that the total number of defects is the smallest in the case of Comparative Example 4 using the filter (2) instead of the filter (1).

Therefore, when the present invention is applied, that is, when filtering a resin composition containing a polymer consisting of a repeating structure of hydrophobic structural units, a filter equipped with a polyolefin resin membrane can be used. , a resin in which impurities are further reduced can be obtained.

DESCRIPTION OF SYMBOLS 1... Substrate, 2... Base layer, 3... Layer, 3a... Phase, 3b... Phase.

Claims (2)

A filtration step of filtering a resin composition containing a polymer through a filter equipped with a polyolefin resin membrane to obtain a purified resin,
The polymer is
A homopolymer consisting of a repeating structure of structural units (u11) derived from styrene;
A copolymer comprising a repeating structure of the structural unit (u11) and a structural unit (u12) derived from a monomer in which the α-position hydrogen atom of styrene is substituted with an alkyl group having 1 to 5 carbon atoms;
the structural unit (u11) and a structural unit (u13) derived from a monomer in which an alkyl group having 1 to 5 carbon atoms is bonded to the benzene ring of styrene, the hydrogen atom at the α-position of which may be substituted with a substituent; a copolymer consisting of a repeating structure of; and a copolymer consisting of a repeating structure of the structural unit (u11), the structural unit (u12), and the structural unit (u13). manufacturing method. a step of filtering a resin composition containing a polymer through a filter equipped with a polyolefin resin membrane to obtain a purified resin;
a step of applying an undercoat agent containing the purified resin onto a substrate to form an undercoat agent layer;
forming a layer containing a block copolymer in which a hydrophobic polymer block and a hydrophilic polymer block are combined on the undercoat layer;
phase separating a layer comprising said block copolymer;
has
The polymer is
A homopolymer consisting of a repeating structure of structural units (u11) derived from styrene;
A copolymer comprising a repeating structure of the structural unit (u11) and a structural unit (u12) derived from a monomer in which the α-position hydrogen atom of styrene is substituted with an alkyl group having 1 to 5 carbon atoms;
the structural unit (u11) and a structural unit (u13) derived from a monomer in which an alkyl group having 1 to 5 carbon atoms is bonded to the benzene ring of styrene, the hydrogen atom at the α-position of which may be substituted with a substituent; a copolymer consisting of a repeating structure of; and a copolymer consisting of a repeating structure of the structural unit (u11), the structural unit (u12) and the structural unit (u13). A method of manufacturing a structure including an isolation structure.

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