WO2016159329A1 - Composition for forming pattern, and pattern forming method - Google Patents

Abstract

This composition for forming a pattern contains a solvent and a block copolymer that forms a phase separation structure by self-assembling, and is characterized in that: the block copolymer has a first block that is composed of a substituted or unsubstituted styrene unit, a second block that is composed of a (meth)acrylate ester unit, and a first group that is bonded to at least one end of the main chain; and the first group is a monovalent group that forms a compound having a ClogP of from -1 to 3 (inclusive) when a methyl group is bonded to the main chain-side bonding hand. It is preferable that the first group is formed by means of a chain terminator; and if this is the case, it is preferable that the ClogP of the chain terminator is from -1.5 to 4.0 (inclusive). The ClogP of a compound that is formed when a methyl group is bonded to the main chain-side bonding hand of the first group is preferably 2.5 or less. The number of carbon atoms in the first group is preferably from 1 to 20 (inclusive). The number of heteroatoms in the first group is preferably from 1 to 5 (inclusive).

Description

Pattern forming composition and pattern forming method

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

With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, pattern miniaturization is required in the pattern formation process. At present, it is possible to form a fine pattern with a line width of about 50 nm using, for example, an ArF excimer laser, but further fine pattern formation has been required.

In response to the above requirements, a method of forming a self-organized pattern using a so-called self-organized phase separation (microdomain) structure that spontaneously forms an ordered pattern has been proposed. As a method for forming such a self-assembled pattern, a block copolymer obtained by copolymerizing a monomer compound having specific properties and a monomer compound having different properties is used, and an ultrafine pattern is formed by self-assembly. There are known methods for forming (see JP 2008-149447 A, JP 2002-519728 A and JP 2003-218383 A). According to this method, by annealing the film containing the block copolymer, it is possible to form a pattern in a self-aligning manner by utilizing the property that polymer structures having the same properties are gathered together.

However, since the pattern obtained by the conventional method cannot be said to be sufficiently fine, various techniques for the structure of the block copolymer and the like have been studied. Those in which atoms are introduced are known (see JP2013-528664A, JP2013-166932A, and ACS Macro Lett., 1, 1279 (2012)). However, even when a composition containing the above conventional block copolymer is used, there is a disadvantage that the occurrence of defects in the formed regular array structure cannot be sufficiently suppressed.

JP 2008-149447 A JP-T-2002-519728 JP 2003-218383 A JP 2013-528664 A JP 2013-166932 A

The present invention has been made based on the circumstances as described above, and the purpose thereof is a pattern capable of forming a self-assembled film with few defects in a regular arrangement structure and thus forming a pattern with a good shape. The object is to provide a forming composition and a pattern forming method.

The invention made in order to solve the above problems includes a block copolymer (hereinafter also referred to as “[A] block copolymer”) that forms a phase separation structure by self-assembly, and a solvent (hereinafter referred to as “[B A first block comprising a substituted or unsubstituted styrene unit (hereinafter also referred to as “repeating unit (I)”). (Hereinafter also referred to as “block (a)”) and a second block (hereinafter also referred to as “block (b)”) comprising a (meth) acrylate unit (hereinafter also referred to as “repeating unit (II)”). And a first group (hereinafter also referred to as “group (1)”) bonded to at least one end of the main chain, and the group (1) binds a methyl group to the main chain side bond. ClogP is -1 or more and 3 or less when Characterized in that it is a monovalent group which forms a compound.

Another invention made to solve the above-described problems includes a step of forming a phase-separated self-assembled film on one surface side of the substrate (hereinafter also referred to as a “self-assembled film forming step”), and the self This is a pattern forming method including a step of removing a part of the organized film (hereinafter also referred to as “removing step”), and forming the self-assembled film with the pattern forming composition.

Here, “Directed Self Assembly” refers to a phenomenon in which an organization or structure is spontaneously built without being caused only by control from an external factor. “Main chain” refers to a chain composed of carbon atoms derived from carbon atoms constituting a polymerizable carbon-carbon double bond of a monomer in a block copolymer. However, the said chain | strand may contain the coupling group in between. “Terminal” in “at least one terminal of the main chain” means that no bond is formed with the adjacent repeating unit among the carbon atoms of the main chain of the repeating unit located at the end of the block copolymer. Refers to a carbon atom. “ClogP” is also referred to as “ClogPow”, and is a value of the octanol / water partition coefficient (logP) calculated by the ClogP method. The larger the value, the higher the hydrophobicity (lipid solubility).

According to the pattern forming composition and the pattern forming method of the present invention, it is possible to form a self-assembled film with few defects in a regular array structure, and thus to form a pattern with a good shape. Therefore, they can be suitably used in pattern formation processes in the manufacture of various electronic devices such as semiconductor devices and liquid crystal devices that are required to be further miniaturized.

It is a typical sectional view showing an example of the state after forming a lower layer film on a substrate. FIG. 2 is a schematic cross-sectional view illustrating an example of a state after forming a pre-pattern on the lower layer film in FIG. 1. It is typical sectional drawing which shows an example after forming a coating film with the composition for pattern formation between the pre-patterns in FIG. It is typical sectional drawing which shows an example of the state after making the coating film in FIG. 3 into a self-organization film | membrane. FIG. 5 is a schematic cross-sectional view showing an example of a state after removing a part of phases and a pre-pattern of the self-assembled film in FIG. 4.

<Pattern forming composition>
The composition for pattern formation of this invention contains a [A] block copolymer and a [B] solvent. The pattern forming composition may contain other optional components as long as the effects of the present invention are not impaired. By forming a film (self-assembled film) having a phase separation structure by self-assembly on one surface side of the substrate with the pattern forming composition, and removing a part of the phase of the self-assembled film A pattern can be formed. Hereinafter, each component will be described.

[[A] block copolymer]
[A] The block copolymer has a block (a), a block (b), and a group (1), and forms a phase separation structure by self-assembly. Each of the blocks is composed of a chain structure of repeating units derived from one type of monomer. In the [A] block copolymer having such a plurality of blocks, the same type of blocks are aggregated by heating or the like 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 periodically and alternately repeated can be formed.

[A] Block (a) where the block copolymer is made of substituted or unsubstituted styrene, block (b) made of (meth) acrylic acid ester, and group (1) bonded to at least one terminal of the main chain And the group (1) is a monovalent group that forms a compound having a ClogP of −1 or more and 3 or less when a methyl group is bonded to the main chain side bond, The composition can form a self-assembled film with few defects in the ordered arrangement structure. Although it is not necessarily clear why the pattern forming composition has the above configuration, the following effects can be inferred, for example. That is, the group (1) is a relatively highly hydrophilic group that forms a compound having a ClogP of −1 or more and 3 or less, assuming that a methyl group is bonded to the main chain side bond. Therefore, by bonding the group (1) to at least one terminal of the main chain, the hydrophilicity of the terminal of the block to which the group (1) is connected can be increased. As a result, the physical property difference such as polarity between the block (a) composed of the relatively hydrophobic repeating unit (I) and the block (b) composed of the relatively hydrophilic repeating unit (II) is moderate. Therefore, it is considered that a self-assembled film with few defects in the regular arrangement structure can be formed.

[A] The block copolymer may further have a block composed of a repeating unit other than the repeating unit (I) and the repeating unit (II). Moreover, the [A] block copolymer may have 1 type or multiple types of block (a), and may have 1 type or multiple types of block (b).

[A] Examples of the block copolymer include a diblock copolymer having 2 blocks, a triblock copolymer having 3 blocks, and a tetrablock copolymer having 4 blocks. . [A] The block copolymer may be either a linear polymer or a branched polymer. As a specific example of the [A] block copolymer which is a branched polymer, a central part and three or more linear blocks (hereinafter also referred to as “arm part”) having one end bonded to the central part And a star-shaped copolymer formed by. The number of arms of the star copolymer can be, for example, 2 or more and 7 or less. Examples of the star copolymer include an asymmetric star copolymer (Miktoarm copolymer). As used herein, the asymmetric star copolymer refers to a star copolymer in which each arm is formed of a different monomer, and is different from a symmetric star polymer in which each arm is formed of the same monomer. Refers to things.

Among these, [A] block copolymers are preferably linear polymers. [A] When the block copolymer is a linear polymer, the [A] block copolymer is a diblock copolymer and a triblock copolymer from the viewpoint of easily forming a desired fine pattern. More preferred are polymers, and even more preferred are diblock copolymers. [A] The block copolymer may have a linking group between the blocks. Hereinafter, each block, group (1) and linking group will be described.

(Block (a))
Block (a) consists of repeating unit (I). The repeating unit (I) is a substituted or unsubstituted styrene unit.

When the repeating unit (I) is a substituted styrene unit, examples of the substituent replacing the styrene unit include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and an isobutyl group. Alkyl groups having 1 to 20 carbon atoms such as tert-butyl group;
An alkenyl group such as an ethenyl group;
Alkoxy groups such as methoxy group and tert-butoxy group;
Groups containing heteroatoms such as an acetoxy group, a nitro group, a cyano group;
Examples thereof include groups containing halogen atoms such as chlorine atom, bromine atom and iodine atom. As the substituent, an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, an alkyl group having 4 carbon atoms is more preferable, and a tert-butyl group is particularly preferable.

The bonding site of the substituent may be a main chain portion of the styrene unit (carbon derived from two carbon atoms constituting the polymerizable carbon-carbon double bond of styrene), or the ortho position of the aromatic ring of the styrene unit, It may be in meta or para position. The binding site for the substituent is preferably the para position of the aromatic ring of the styrene unit.

The number of the substituents in the substituted styrene unit is not particularly limited, but is preferably 1 to 3, more preferably 1 and 2, and further preferably 1.

As the styrene unit, a substituted styrene unit is preferred, a styrene unit substituted with an alkyl group is more preferred, a styrene unit substituted with a tert-butyl group is more preferred, and the para position of the aromatic ring is substituted with a tert-butyl group The styrene units made are particularly preferred.

(Block (b))
Block (b) consists of repeating unit (II). The repeating unit (II) is a (meth) acrylic acid ester unit. Examples of the monomer giving the (meth) acrylate unit include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. (Meth) acrylic acid alkyl ester; (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid 1-methylcyclopentyl, (meth) acrylic acid 2-ethyladamantyl, (meth) acrylic acid 2- ( (Meth) acrylic acid alicyclic saturated hydrocarbon esters such as adamantane-1-yl) propyl;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and naphthyl (meth) acrylate;
Examples include (meth) acrylic acid-substituted alkyl esters such as 2-hydroxyethyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, and 3-glycidylpropyl (meth) acrylate. As the monomer that gives the (meth) acrylic acid ester unit, (meth) acrylic acid alkyl ester is preferable from the viewpoint of improving pattern formability and increasing the pattern height after pattern formation. Methyl acid is more preferred.

[A] When the block copolymer is a diblock copolymer, the mass ratio ((I) / (II)) of the content ratio of the repeating unit (I) to the repeating unit (II) in the [A] block copolymer Can be appropriately selected according to the line / space width ratio of the desired line and space pattern, the dimensions of the contact hole pattern or the cylinder pattern, and the like. When forming a line and space pattern, the mass ratio is preferably in the range of 40/60 to 60/40, more preferably 50/50, from the viewpoint of forming a better phase separation structure. . When forming a hole pattern, the mass ratio is preferably in the range of 30/70 to 40/60, or 70/30 to 60/40. Thus, it becomes easy to form a favorable hole pattern by making the said mass ratio into the said range, ie, the range comparatively close to 35/65 or 65/35.

(Group (1))
The group (1) is bonded to at least one terminal of the main chain of the [A] block copolymer. The group (1) is preferably linked to the block (b). The group (1) may be bonded to a plurality of terminals of the main chain of the [A] block copolymer. In this case, the plurality of groups (1) may be the same or different.

The group (1) is preferably formed by a terminal terminator described later and a group formed by a polymerization initiator, and more preferably formed by a terminal terminator.

The group (1) is a monovalent group that forms a compound having a ClogP of −1 or more and 3 or less when a methyl group is bonded to the main chain side bond. The lower limit of ClogP is preferably −0.7, more preferably −0.5, and further preferably −0.4. On the other hand, the upper limit of ClogP is preferably 2.5, more preferably 1.8, still more preferably 1.0, and particularly preferably 0. By setting the ClogP in the above range, the pattern forming composition can form a self-assembled film with fewer defects in the ordered arrangement structure.

As the above ClogP, a value obtained by using molecular model creation software (for example, “Chem Bio Draw Ultra 13.0, Chemical properties window” built in “Chemdraw Ver. 12” of CambridgeSoft) is used.

In addition, ClogP of the compound formed when a methyl group is bonded to the main chain side bond described above is a parameter that indirectly represents the hydrophilicity of the group (1). Here, the methyl group is a relatively small, simple and non-polar group. Therefore, no matter what structure the group (1) has, the influence of the methyl group on the ClogP is relatively small and substantially constant. Therefore, the ClogP is a parameter that increases or decreases mainly with the hydrophilicity of the group (1), and reflects the tendency of the hydrophilicity of the group (1) with high accuracy.

The lower limit of the carbon number of the group (1) is usually 1, preferably 2 and more preferably 3. On the other hand, as an upper limit of carbon number of group (1), 20 is preferable, 10 is more preferable, 7 is further more preferable, and 6 is especially preferable. By setting the number of carbon atoms contained in the group (1) within the above range, the ClogP can be easily adjusted to the above range.

Group (1) usually contains a heteroatom. As a minimum of the number of heteroatoms of group (1), 1 is preferred and 2 is more preferred. On the other hand, the upper limit of the number of heteroatoms in the group (1) is preferably 5, more preferably 4, and even more preferably 3. By making the number of heteroatoms of group (1) into the said range, it becomes easy to adjust the said ClogP to the said range. Here, the “hetero atom” refers to an atom other than a carbon atom and a hydrogen atom. When the number of heteroatoms in the group (1) is 2 or more, the 2 or more heteroatoms may be the same or different.

Particularly, the group (1) preferably has 6 or less carbon atoms and 2 or more heteroatoms. Thus, since the number of carbon atoms in the group (1) is relatively small and the number of heteroatoms is relatively large, the ClogP can be easily adjusted in the above range.

Examples of the hetero atom include halogen atoms such as fluorine atom, chlorine atom and bromine atom, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom and silicon atom, and among these, oxygen atom, nitrogen atom and sulfur atom. Atoms are preferred.

As the group (1), for example, a part or all of hydrogen atoms of a group containing a hetero atom-containing group between carbon-carbon of a hydrocarbon group, a hydrocarbon group, or a group containing a hetero atom-containing group described above And a group substituted with.

Here, the “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, the alicyclic hydrocarbon group does not need to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not need to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

Examples of the monovalent hydrocarbon group include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent hydrocarbon having 6 to 20 carbon atoms. And aromatic hydrocarbon groups.

Examples of the monovalent chain hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group;
An alkenyl group such as an ethenyl group, a propenyl group, a butenyl group;
Examples thereof include alkynyl groups such as ethynyl group and propynyl group.

Examples of the monovalent alicyclic hydrocarbon group include monovalent monocyclic alicyclic saturated hydrocarbon groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;
A monovalent monocyclic alicyclic unsaturated hydrocarbon group such as a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group;
Monovalent polycyclic alicyclic saturated hydrocarbon group such as norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl group;
And monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as a norbornenyl group, a tricyclodecenyl group, and a tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, anthryl group, and trityl group;
Examples include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and the like.

Examples of the hetero atom-containing group include —CO— (carbonyl group), —CS— (thiocarbonyl group), —O— (ether group), —S— (thioether group), —COO— (ester group), And —SO ₂ — (sulfonyl group), —SO ₂ O— (thioester group), or a combination of these.

Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom;
Alkoxy groups such as methoxy group, ethoxy group, 2-ethylpentoxy group, carboxy group, hydroxy group, cycloalkoxy group, aryloxy group, alkoxycarbonyl group, cycloalkyloxyoxycarbonyl group, aryloxycarbonyl group, acyl group, Examples thereof include polar groups such as amino group, amide group, cyano group, isocyanate group and sulfo group. The amino group includes an amino group in which part or all of the hydrogen atoms are substituted with an alkyl group such as a methyl group or an ethyl group.

Examples of the group (1) include groups represented by the following formulas (1-1) to (1-7) (hereinafter also referred to as “group (1-1) to group (1-7)”). It is done.

In the above formulas (1-1) to (1-7), R ¹ is a monovalent organic group containing a hetero atom having 1 to 20 carbon atoms. However, the group represented by the above formula (1-1) does not include the groups represented by the above formulas (1-2) to (1-7). R ² , R ³ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 10 carbon atoms. R ⁴ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁷ is a monovalent hydrocarbon group having 1 to 10 carbon atoms. t is an integer of 1 to 2. u and v are each independently an integer of 0 to 2. Me is a methyl group. * Indicates a main chain side bond which is a site bonded to the end of the main chain of the [A] block copolymer.

Examples of the monovalent organic group containing a hetero atom having 1 to 20 carbon atoms represented by R ¹ include a group containing a hetero atom-containing group between carbon-carbon of a hydrocarbon group, a hydrocarbon group, or the above hetero atom. Examples include a group in which part or all of the hydrogen atoms of the group including the containing group are substituted with a substituent. Examples of the hydrocarbon group, heteroatom-containing group, and substituent include the same groups as described above. The monovalent organic group containing a hetero atom having 1 to 20 carbon atoms represented by R ¹ is preferably a group containing an ester group, a group containing a carboxy group, or a group containing —SO ₂ —. The ester group contained in R ¹ may form a lactone structure. Further, the group represented by the above formula (1-1) is preferably introduced into the [A] block copolymer using a halogen compound described later. R ¹ preferably does not contain a hydroxy group from the viewpoint of ease of introduction when the group represented by the formula (1-1) is introduced into the [A] block copolymer using a halogen compound. .

Examples of the alkyl group represented by R ² , R ^3, and R ⁶ include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these, a methyl group is preferable.

Examples of the alkyl group represented by R ⁵ include a methyl group, an ethyl group, a propyl group, and a 2-ethylhexyl group. Among these, a methyl group and a 2-ethylhexyl group are preferable, and a methyl group is more preferable. .

Examples of the monovalent organic group represented by R ⁴ include the same groups as the monovalent organic group represented by R ¹ . R ⁴ is preferably a methyl group.

Examples of the monovalent hydrocarbon group represented by R ⁷ include a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, and a carbon number. Examples thereof include monovalent aromatic hydrocarbon groups of 6 to 10, among which an aromatic hydrocarbon group is preferable, and a phenyl group is more preferable.

The t is preferably 1. Moreover, as said u and v, 0 and 1 are preferable and 1 is more preferable.

Specific examples of the group (1) include groups represented by the following formulas. In the following formula, the value of ClogP of a compound formed when a methyl group is bonded to the main chain side bond of each group is also shown.

In the above formula, * indicates a main chain side bond that is a site bonded to the end of the main chain of the [A] block copolymer. Me is a methyl group. Et is an ethyl group.

As the group (1), those containing a hydroxy group, an amino group, a carbonyl group, a carboxyl group, a sulfonyl group, an ester group, a thiol group, an alkoxy group and a combination thereof are preferable. A hydroxy group, an amino group, a methoxy group and an ethoxy group are preferable. More preferred are those containing at least two of the groups.

In addition, when the group (1) is bonded only to one end of the main chain of the [A] block copolymer, the other end of the main chain may be unmodified, and a terminal group other than the group (1) is bonded. You may do it. Examples of the terminal group other than the group (1) include an alkyl group having 1 to 10 carbon atoms.

(Linking group)
[A] The block copolymer may have a linking group between the adjacent block (a) and block (b). In some cases, the pattern forming composition can form a self-assembled film with fewer defects in the regularly arranged structure because the [A] block copolymer has a linking group. Examples of the linking group include divalent organic groups having 1 to 50 carbon atoms. The divalent organic group is preferably a divalent organic group having 1 to 20 carbon atoms having one or more aromatic rings, and two of the hydrogen atoms of the alkanediyl group having 1 to 5 carbon atoms are aromatic. A group substituted with a group hydrocarbon group is more preferred. Examples of the alkanediyl group include a methyl group, an ethyl group, and a propyl group, and an ethyl group is preferable. Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group, and a phenyl group is preferable.

Examples of the monomer that gives the linking group include diphenylethylene. Diphenylethylene improves the stability of the anion terminal produced in the middle when the [A] block copolymer is synthesized by anionic polymerization. Thereby, the dispersion degree of the obtained [A] block copolymer becomes smaller, and as a result, the variation in the dimension of the pattern formed by the pattern forming composition can be further reduced. [A] The block copolymer may have one or more linking groups.

[A] The lower limit of the weight average molecular weight (Mw) of the block copolymer is preferably 5,000, more preferably 10,000, even more preferably 15,000, and particularly preferably 21,000. On the other hand, the upper limit of Mw of the [A] block copolymer is preferably 100,000, more preferably 75,000, still more preferably 40,000, and particularly preferably 24,000. [A] By making Mw of a block copolymer into the said range, a more favorable phase-separation structure can be formed.

[A] The lower limit of the number average molecular weight (Mn) of the block copolymer is preferably 4,500, more preferably 9,500, still more preferably 14,500, and particularly preferably 20,000. On the other hand, the upper limit of Mn of the [A] block copolymer is preferably 95,000, more preferably 72,000, further preferably 38,000, and particularly preferably 23,500. [A] By making Mn of a block copolymer into the said range, a more favorable phase-separation structure can be formed.

[A] The lower limit of the degree of dispersion (Mw / Mn) of the block copolymer is usually 1. On the other hand, the upper limit of Mw / Mn of the [A] block copolymer is usually 4, preferably 2, more preferably 1.5, still more preferably 1.2, and particularly preferably 1.1. [A] By making Mw / Mn of a block copolymer into the said range, a more favorable phase-separation structure can be formed.

Here, Mw and Mn of the [A] block copolymer are values measured by GPC under the following conditions.
GPC column: 2 "G2000HXL" manufactured by Tosoh Corporation, 1 "G3000HXL" and 1 "G4000HXL" Eluent: Tetrahydrofuran (for example, manufactured by Wako Pure Chemical Industries, Ltd.)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[A] The lower limit of the content of the block copolymer is preferably 80% by mass, more preferably 90% by mass, still more preferably 95% by mass, based on the total solid content in the pattern forming composition. 99 mass% is especially preferable.

The lower limit of the concentration of the [A] block copolymer in the pattern forming composition is preferably 0.3% by mass, more preferably 0.7% by mass, still more preferably 1.0% by mass, and 1.3% Mass% is particularly preferred. On the other hand, the upper limit of the concentration of the [A] block copolymer in the pattern forming composition is preferably 5% by mass, more preferably 3% by mass, further preferably 2% by mass, and particularly preferably 1.7% by mass. preferable.

([A] Synthesis method of block copolymer)
[A] As a method for synthesizing a block copolymer, for example, a first method in which each block is formed in a desired order and then the group (1) is introduced by treating the polymerization terminal with a terminal stopper, Polymerization is started using the polymerization initiator that forms (1), and the block is formed by treating the polymerization terminal with a terminal terminator after the second method that forms each block in the desired order. The 3rd method etc. which introduce | transduce (1) into both ends are mentioned, Among these, the 1st method is preferable. [A] Each block of the block copolymer can be synthesized by, for example, living cation polymerization, living anion polymerization, living radical polymerization, coordination polymerization (Ziegler-Natta catalyst, metallocene catalyst), and the like. Living anionic polymerization is preferable from the viewpoint that (1) can be easily introduced. [A] When the block copolymer is an asymmetric star copolymer (Mictoarm type copolymer), the [A] block copolymer is 1,3-bis (1-phenylethenyl) benzene. It can be synthesized from a method using anionic polymerization via a method, a method using a group capable of binding an arm from a method such as click chemistry, a method using a reagent having a different starting point in the polymerization system, and the like.

For example, when the block copolymer [A] is a diblock copolymer having a block (a) and a block (b), an anionic polymerization initiator is first used as a method of synthesizing each block by living anionic polymerization. After the block (a) is formed by polymerization of the monomer that gives the block (a) in an appropriate solvent, the monomer that gives the block (b) is added in the same manner, and the block (a) is connected to the block. (B) is formed. A linking group may be formed between the block (a) and the block (b) by a reaction such as diphenylethylene.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone, cyclohexanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. These solvents can be used alone or in combination of two or more.

The reaction temperature in the polymerization may be appropriately determined according to the type of polymerization initiator described later, but the lower limit of the reaction temperature is usually −150 ° C., and preferably −80 ° C. On the other hand, the upper limit of the reaction temperature is usually 50 ° C, preferably 40 ° C. The lower limit of the reaction time in the polymerization is usually 5 minutes, and preferably 20 minutes. On the other hand, the upper limit of the reaction time in the polymerization is usually 24 hours and preferably 12 hours.

Examples of the polymerization initiator used in the polymerization include alkyl lithium, alkyl magnesium halide, sodium naphthalene, alkylated lanthanoid compounds; potassium alkoxides such as t-butoxy potassium and 18-crown-6-ether potassium; dimethyl zinc, Alkyl zinc such as diethyl zinc; alkyl aluminum such as trimethylaluminum; aromatic metal compounds such as benzyl potassium, cumyl potassium, cumyl cesium, and the like.

When the group (1) is formed with the polymerization initiator, the lower limit of the ClogP of the polymerization initiator is preferably -1, more preferably -0.3, and even more preferably 0.3. On the other hand, the upper limit of ClogP of the polymerization initiator is preferably 2, more preferably 1, and still more preferably 0.4. Thus, by making ClogP of the said polymerization initiator into the said range, it becomes easy to introduce | transduce relatively high hydrophilic group (1) into a [A] block copolymer. ClogP of the polymerization initiators represented by the following formulas (i-1) to (i-5) (hereinafter also referred to as “polymerization initiators (i-1) to (i-5)”) are polymerized respectively. The initiator (i-1) is 3.17, the polymerization initiator (i-2) is 3.57, the polymerization initiator (i-3) is 0.368, and the polymerization initiator (i-4) is 3.3. 21. The polymerization initiator (i-5) is 3.37. In addition, ClogP of a polymerization initiator is ClogP calculated | required from the structure of the polymerization initiator itself, and when a polymerization initiator is an ionic compound, ClogP calculated | required from the structure of the state in which the anion and the cation couple | bonded.

When the monomer to be polymerized is styrene, 4-tert-butylstyrene or methyl methacrylate, the polymerization initiator used for the polymerization is preferably an alkyl lithium compound, more preferably sec-butyl lithium. When the group (1) is formed with the polymerization initiator, the polymerization initiator (i-3) is preferred as the polymerization initiator used for the polymerization.

When a terminal terminator is used for introducing the group (1), examples of the terminal terminator include halogen compounds in which the group (1) and a halogen atom are bonded, dialkylformamide, glycidyl ether, epoxycycloalkane, epoxy compounds (provided that , Except for the above-mentioned glycidyl ether and epoxycycloalkane), substituted or unsubstituted thiirane or substituted or unsubstituted thietane, alkylpyrrolidone, carbon dioxide and the like. Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom. Among these, a chlorine atom and a bromine atom are preferable, and a bromine atom is more preferable.

The lower limit of ClogP of the above end terminator is preferably -1.5, more preferably -1.0, still more preferably -0.5, and particularly preferably -0.3. On the other hand, the upper limit of ClogP of the terminal stopper is preferably 4.0, more preferably 3.2, further preferably 2.2, particularly preferably 1.4, and particularly preferably 0. By making ClogP of the said terminal terminator into the said range, it becomes easy to introduce | transduce group (1) with comparatively high hydrophilicity into a [A] block copolymer.

In the case of introducing the group (1-1), for example, the above halogen compound or carbon dioxide can be used as a terminal terminator. When the group (1-2) is introduced, for example, dialkylformamide can be used as the terminal terminator. When the group (1-3) is introduced, for example, substituted or unsubstituted thiirane or substituted or unsubstituted thietane can be used as the terminal terminator. When introducing the group (1-4), for example, glycidyl ether can be used as the terminal terminator. When introducing the group (1-5), for example, alkylpyrrolidone can be used as the terminal terminator. When the group (1-6) is introduced, for example, an epoxy compound described later can be used as the terminal terminator. When introducing the group (1-7), for example, an epoxycycloalkane can be used as a terminal terminator.

As a specific method for introducing the group (1) by treating the polymerization terminal with a terminal terminator, for example, a method as shown in the following scheme and the like can be mentioned. That is, the block copolymer obtained by the above-described living anion polymerization or the like is modified by adding a terminal terminator to modify the terminal [A] block copolymer in which the group (1) is introduced at the terminal of the main chain. A polymer can be obtained. In the following scheme, block (a) is a polystyrene block, block (b) is a methyl (meth) acrylate block, and a terminal terminator is an epoxy compound described later. The group (1) to be introduced is a group (1-4).

In the above scheme, n is an integer of 2 or more. m is an integer of 1 or more. R ⁵ has the same meaning as in the above formula (1-4).

Even when the terminal terminator is a halogen compound, dialkylformamide, alkylpyrrolidone, substituted or unsubstituted thiirane, substituted or unsubstituted thietane, glycidyl ether, epoxycycloalkane, carbon dioxide, etc., the main chain is obtained by the same method. The group (1) can be introduced at the end of

The above [A] block copolymer 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, ultrapure water, alkanes and the like can be used singly or in combination 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.

[[B] solvent]
The pattern forming composition contains a [B] solvent. [B] The solvent is not particularly limited as long as it can dissolve or disperse at least the [A] block copolymer.

[B] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol. , Sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethyl Hexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, s monoalcohol solvents such as ec-heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

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

Examples of the ketone solvent 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, and 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:
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

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

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, and acetic acid. acetate solvents such as sec-pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Lactone solvents such as γ-butyrolactone and valerolactone;
Carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate;
Diethyl acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of the hydrocarbon solvent include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, Aliphatic hydrocarbon solvents such as cyclohexane and methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

Among these, ester solvents and ketone solvents are preferable, ester solvents are more preferable, polyhydric alcohol partial ether acetate solvents are more preferable, and propylene glycol monomethyl ether acetate is particularly preferable. The pattern forming composition may contain one or more [B] solvents.

[Optional ingredients]
As an arbitrary component which the said composition for pattern formation may contain, surfactant etc. are mentioned, for example. The said pattern formation composition can improve the applicability | paintability to a board | substrate etc. more by containing surfactant.

<Pattern formation method>
The pattern forming method of the present invention includes a step of forming a self-assembled film with the pattern forming composition and a step of removing a part of the self-assembled film. The pattern forming method includes a step of forming a lower layer film on one surface side of the substrate (hereinafter also referred to as “lower layer film forming step”) and / or one of the substrates before the self-assembled film forming step. You may further provide the process (henceforth a "pre-pattern formation process") which forms a pre pattern in the surface side. According to the pattern forming method, since the above-described pattern forming composition is used for forming the self-assembled film, it is possible to form a self-assembled film with few defects in the ordered arrangement structure, and thus a good shape. A pattern can be formed. Hereinafter, each process will be described with reference to the drawings.

[Lower layer formation process]
This step is a step of forming a lower layer film on one surface side of the substrate. Thereby, as shown in FIG. 1, a substrate with a lower layer film in which the lower layer film 102 is formed on one surface (upper surface) side of the substrate 101 can be obtained. The self-assembled film in the self-assembled film forming step described later is formed on the surface of the lower layer film 102 opposite to the substrate 101. 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 each block of the [A] block copolymer contained in the pattern forming composition. Therefore, the structure control may be facilitated by forming the lower layer film 102. Furthermore, when the self-assembled film is a thin film, the transfer process can be improved by forming it on 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.

As the underlayer film forming composition used for forming the underlayer film 102, conventionally known organic underlayer film forming materials and the like can be used, and examples thereof include an underlayer film forming composition containing a crosslinking agent.

A method for forming the lower layer film 102 is not particularly limited. For example, the lower layer film forming composition is applied on the substrate 101 by a known method such as a spin coating method, and then cured by exposure and / or heating. The method of forming etc. are mentioned. 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. Although it does not specifically limit as a minimum of the said heating temperature, 90 degreeC is preferable. On the other hand, the upper limit of the heating temperature is not particularly limited, but is preferably 550 ° C, more preferably 450 ° C, and further preferably 300 ° C. As a minimum of the above-mentioned heating time, 5 seconds are preferred, 10 seconds are more preferred, and 20 seconds are still more preferred. On the other hand, the upper limit of the heating time is preferably 1,200 seconds, more preferably 600 seconds, and even more preferably 300 seconds. The lower limit of the average thickness of the lower layer film 102 is not particularly limited, but is preferably 1 nm, more preferably 2 nm, and further preferably 3 nm. On the other hand, the upper limit of the average thickness of the lower layer film 102 is not particularly limited, but is preferably 20,000 nm, more preferably 1,000 nm, still more preferably 100 nm, and particularly preferably 10 nm.

[Pre-pattern forming process]
This step is a step of forming the pre-pattern 103. This pre-pattern may be formed on the substrate, or may be formed on the surface of the lower layer film 102 opposite to the substrate 101 as shown in FIG. By forming the pre-pattern 103, the shape of the phase separation structure by self-organization of a coating film 104 (see FIG. 3) described later is controlled, and a finer pattern can be formed. Further, the phase separation structure of the self-assembled film obtained by the pattern forming composition can be finely controlled by the material, size, shape and the like of the prepattern 103. Note that the pre-pattern 103 can be appropriately selected according to the shape of a desired pattern. For example, a line and space pattern, a hole pattern, a cylinder pattern, or the like can be used. When the pattern forming method includes a pre-pattern forming step, a self-assembled film 105 to be described later is formed in a non-stacked region of the normal pre-pattern 103.

As a method for forming the pre-pattern 103, a method similar to a known resist pattern forming method may be used. In addition, as a composition used for forming the pre-pattern 103, a conventional resist composition such as a composition containing a polymer having an acid dissociable group, a radiation sensitive acid generator and an organic solvent may be used. it can. Specifically, for example, a commercially available chemically amplified resist composition is applied onto the substrate 101 or 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 electromagnetic waves such as ultraviolet rays, far ultraviolet rays, and X-rays; and charged particle beams such as electron beams and α rays. Among these, far ultraviolet rays are preferable, ArF excimer laser light and KrF excimer laser are more preferable, and ArF excimer laser light is more preferable. Moreover, immersion exposure can also be performed as an exposure method. Subsequently, a desired pre-pattern 103 can be formed by performing post-exposure baking (PEB) and performing development using an alkali developer, a developer containing an organic solvent as a main component, or the like. It is preferable that the obtained pre-pattern 103 further accelerates curing by, for example, heat treatment after irradiating ultraviolet rays having a wavelength of 254 nm. The lower limit of the heat treatment temperature is 100 ° C., for example. On the other hand, the upper limit of the heat treatment temperature is, for example, 200 ° C. The lower limit of the heat treatment time is, for example, 1 minute. On the other hand, the upper limit of the heat treatment time is, for example, 30 minutes.

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, the self-organization of the coating film 104 can be further promoted.

[Self-assembled film formation process]
This step is a step for forming a phase-separated self-assembled film (self-assembled film having a phase-separated structure) on the 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, thereby forming a self-assembled film having a phase separation structure. 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. 104 is formed, and a self-assembled film 105 having a phase separation structure is formed on the lower layer film 102 formed on the substrate 101. Examples of the self-assembled film to be formed include a film having a phase separation structure having an interface substantially perpendicular to the substrate 101, such as the self-assembled film 105 in FIG. In this step, by using the pattern forming composition, it is possible to obtain the self-assembled film 105 with few defects in the regularly arranged structure while suppressing coating defects due to excellent coating properties.

When a pre-pattern is formed on the substrate 101, the phase separation structure is preferably formed along the pre-pattern, and the interface formed by the phase separation is substantially parallel to the side surface of the pre-pattern. More preferred. For example, when the lamellar phase separation structure shown in FIG. 4 is formed, among the blocks of the [A] block copolymer, a block having high affinity with the side surface of the pre-pattern 103 (referred to as “block (β)”) Forms a block (β) phase 105 b along the pre-pattern 103, and a block having a low affinity (referred to as “block (α)”) forms a block (α) phase 105 a at a position away from the pre-pattern 103. . The phase separation structure formed in this step is composed of a plurality of phases, but the interface itself is not necessarily clear.

The method for applying the pattern forming composition to one surface side of the substrate 101 to form the coating film 104 is not particularly limited. For example, the pattern forming composition to be used is applied by a spin coating method or the like. And the like. Thereby, the composition for pattern formation can be applied onto the substrate 101. Further, when the prepattern 103 is formed on the substrate 101, the pattern forming composition can be filled between the prepatterns 103 on the lower layer film 102. The lower limit of the average thickness of the coating film 104 to be formed is, for example, 10 nm. On the other hand, the upper limit of the average thickness of the formed coating film 104 is, for example, 60 nm.

Examples of a method for forming the self-assembled film 105 by phase-separating the coating film 104 include an annealing method. Examples of the annealing method include a method of heating with an oven, a hot plate or the like. As a minimum of annealing temperature, it is usually 80 ° C, 120 ° C is preferred, 160 ° C is more preferred, and 200 ° C is still more preferred. On the other hand, the upper limit of the annealing temperature is usually 400 ° C., preferably 350 ° C., more preferably 300 ° C., and particularly preferably 260 ° C. As a minimum of annealing time, 10 seconds are preferred, 20 seconds are more preferred, 40 seconds are still more preferred, and 90 seconds are especially preferred. On the other hand, the upper limit of the annealing time is preferably 120 minutes, more preferably 30 minutes, further preferably 10 minutes, and particularly preferably 3 minutes. The lower limit of the average thickness of the self-assembled film 105 thus obtained is preferably 0.1 nm, more preferably 1 nm, and more preferably 5 nm. On the other hand, the upper limit of the average thickness of the self-assembled film 105 is preferably 500 nm, more preferably 100 nm, and even more preferably 50 nm.

[Removal process]
As shown in FIGS. 4 and 5, this step is a step of removing a part of the block (α) phase 105 a in the phase separation structure of the self-assembled film 105. The block (α) phase 105a can be removed by an etching process using the difference in etching rate of each phase separated by self-assembly. In addition, you may irradiate a radiation before the said etching process as needed. As the radiation, for example, when the phase to be removed by etching is a poly (meth) acrylate block phase, radiation having a wavelength of 254 nm can be used. Since the poly (meth) acrylic acid ester block phase is decomposed by the radiation irradiation, it is more easily etched.

Examples of the method for removing the block (α) phase include known methods such as reactive ion etching (RIE) such as chemical dry etching and chemical wet etching; and physical etching such as sputter etching and ion beam etching. Of these, reactive ion etching (RIE) is preferable. Among them, chemical dry etching using CF ₄ , O ₂ gas, etc., and chemical wet etching (wet development) using a liquid etching solution such as an organic solvent or hydrofluoric acid. 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 propion Saturated carboxylic acid esters such as methyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone; methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, etc. Examples include alcohols. These solvents can be used alone or in combination of two or more. In this step, instead of removing the block phase (α), the block phase (β) may be removed.

[Pre-pattern removal process]
When the pre-pattern 103 is formed on the substrate, it is preferable to remove the pre-pattern 103 by this step as shown in FIGS. By removing the pre-pattern 103, it is possible to form a finer and more complicated pattern (pattern consisting of 105b in FIG. 5). Note that the description of the removal method of the block (α) phase 105a described above can be applied to the removal method of the pre-pattern 103. Moreover, this process may be performed simultaneously with the said removal process, and may be performed before or after a removal process.

[Substrate pattern formation process]
The pattern forming method further includes a normal substrate pattern forming step after the removing step. This step is a step of patterning by etching the lower layer film 102 and the substrate 101 using a part of the remaining self-assembled film (pattern consisting of 105b in FIG. 5) as a mask. After the patterning on the substrate 101 is completed, the block (β) phase 105b used as a mask is removed from the substrate by a dissolution treatment or the like, and finally a patterned substrate (pattern) can be obtained. Examples of the obtained pattern include a line and space pattern and a hole pattern. As the etching method, the same method as in the removing step can be used, and the etching gas and the etching liquid can be appropriately selected according to the material of the substrate and the like. For example, when the substrate is made of a silicon material, a mixed gas of chlorofluorocarbon gas and SF ₄ 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. A pattern obtained by the pattern forming method is suitably used for a semiconductor element or the like, and the semiconductor element is widely used for an LED, a solar cell or the like.

[A] The ratio of the length of each block in the block copolymer molecule, [A] the length of the block copolymer molecule (weight average molecular weight, etc.), the lower layer film, the prepattern, etc. In addition to the lamellar structure shown in FIG. 4, it is possible to form a self-assembled film having a phase separation structure such as a sea-island structure, a cylinder structure, or a bicontinuous structure. A fine pattern can be obtained.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measuring method of each physical property value is shown below.

[Mw and Mn]
Mw and Mn of each polymer were measured by GPC under the following conditions.
GPC column: two "G2000HXL", one "G3000HXL", and one "G4000HXL" manufactured by Tosoh Corporation Eluent: Tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[ ¹ H-NMR analysis]
¹ H-NMR analysis was performed using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.). The content ratio of each repeating unit in each polymer was calculated from the area ratio of peaks corresponding to each repeating unit in the spectrum obtained by ¹ H-NMR.

[Synthesis Example 1] (Synthesis of block copolymer (A-1))
After drying the 500 mL flask reaction vessel under reduced pressure, 168 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. To this tetrahydrofuran, 4.52 mL (2.26 mmol) of 0.5N tetrahydrofuran solution of lithium chloride was added and stirred sufficiently. Thereafter, 1.26 mL (1.13 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was injected into the stirred solution, and then 13.7 mL (74%) of 4-tert-butylstyrene subjected to distillation dehydration treatment. .8 mmol) and 10 g of tetrahydrofuran that had been subjected to distillation treatment were added dropwise over 30 minutes. At the time of this dropwise injection, care was taken that the internal temperature of the reaction solution did not exceed -65 ° C. After completion of the dropwise addition, the mixture was aged for 120 minutes, and then 10 g of tetrahydrofuran and 12.7 mL (119.8 mmol) of methyl methacrylate were added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was aged for 120 minutes, and then 0.045 g (1.13 mmol) of methanol as an end terminator (C-1) was added to terminate the polymerization end. The obtained polymer solution was purified by precipitation in methanol, and then filtered to obtain a white solid.

The obtained white solid was dissolved in methyl isobutyl ketone to give a 10% by mass solution. To this solution, 500 g of a 1% by mass oxalic acid aqueous solution was poured and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove the Li salt. Thereafter, 500 g of ultrapure water was poured into this solution and stirred, and the lower aqueous layer was removed. This operation was repeated three times to remove oxalic acid. Thereafter, the solution was concentrated and dropped into 2,000 g of methanol to precipitate a polymer. This polymer was filtered under reduced pressure, further washed twice with methanol, and then dried under reduced pressure at 60 ° C. to obtain a white block copolymer (A-1). This block copolymer (A-1) had Mw of 22,274, Mn of 21,584, and Mw / Mn of 1.03. Further, as a result of ¹ H-NMR analysis, the block polymer (A-1) was found to contain each of the repeating units (I) derived from 4-tert-butylstyrene and the repeating units (II) derived from methyl methacrylate. Were 50.0 mass% (39 mol%) and 50.0 mass% (61 mol%), respectively. The block copolymer (A-1) is a diblock copolymer.

[Synthesis Examples 2 to 12, and 16 to 21] (Synthesis of Block Copolymers (A-2) to (A-12) and (A-16) to (A-21))
The block copolymers (A-2) to (A-12) and (A-16) to (A-21) were prepared in the same manner as in Synthesis Example 1 except that the terminal terminator shown in Table 1 was used. Was synthesized.

[Synthesis Examples 13 to 15] (Synthesis of block copolymers (A-13) to (A-15))
A block copolymer (1) was prepared in the same manner as in Synthesis Example 1 except that 13.3 ml (115.2 mmol) of styrene was used in place of 4-tert-butylstyrene, and the terminal terminator shown in Table 1 below was used. A-13) to (A-15) were synthesized.

[Synthesis Example 22] (Synthesis of block copolymer (A-22))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.55 mL (0.49 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this tetrahydrofuran, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. Styrene 22.1 mL (0.192 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.21 mL (0.0015 mol) of 1,1-diphenylethylene and 1.96 mL (0.0010 mol) of 0.5N tetrahydrofuran solution of lithium chloride were added, and the polymerization system was dark red It was confirmed that it became. Further, 20.3 mL (0.192 mol) of methyl methacrylate subjected to adsorption filtration with silica gel for removing the polymerization inhibitor and distilled and dehydrated was added dropwise to this solution over 30 minutes to make the polymerization system light yellow. After that, it was reacted for 120 minutes. Thereafter, 1 mL (24.7 mmol) of methanol as a terminal terminator (C-1) was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove metallic Li. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer. This polymer was filtered under reduced pressure, further washed twice with methanol, and then dried under reduced pressure at 60 ° C. to obtain 38.5 g of a white block copolymer (A-22).

This block copolymer (A-22) had Mw of 42,000, Mn of 40,000, and Mw / Mn of 1.05. Further, as a result of ¹ H-NMR analysis, the block copolymer (A-22) had a content ratio of the repeating unit (I) derived from styrene and the repeating unit (II) derived from methyl methacrylate of 50. They were 0 mass% (50.3 mol%) and 50.0 mass% (49.7 mol%). The block copolymer (A-22) is a diblock copolymer.

[Synthesis Example 23] (Synthesis of block copolymer (A-23))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.30 mL (0.28 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this tetrahydrofuran, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. Styrene 22.1 mL (0.192 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.11 mL (0.00078 mol) of 1,1-diphenylethylene and 1.04 mL (0.0005 mol) of 0.5N tetrahydrofuran solution of lithium chloride were added, and the polymerization system was dark red It was confirmed that it became. Further, 21.2 mL (0.200 mol) of methyl methacrylate subjected to adsorption filtration with silica gel for removing the polymerization inhibitor and distilled and dehydrated was added dropwise to this solution over 30 minutes to make the polymerization system light yellow. After that, it was reacted for 120 minutes. Thereafter, 1 mL (24.7 mmol) of methanol as a terminal terminator (C-1) was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove metallic Li. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer. The polymer was filtered under reduced pressure, further washed twice with methanol, and then dried under reduced pressure at 60 ° C. to obtain 38.5 g of a white block copolymer (A-23).

This block copolymer (A-23) had Mw of 81,000, Mn of 77,000, and Mw / Mn of 1.05. Further, as a result of ¹ H-NMR analysis, the block copolymer (A-23) has a content ratio of the repeating unit (I) derived from styrene and the repeating unit (II) derived from methyl methacrylate of 50. They were 0 mass% (50.3 mol%) and 50.0 mass% (49.7 mol%). The block copolymer (A-23) is a diblock copolymer.

The end terminator used for the synthesis of the block copolymers (A-1) to (A-23) is as follows: the end terminator (C-1) is methanol, and the end terminator (C-2) is α-bromo-γ. -Butyrolactone, terminal stopper (C-3) is N, N-dimethylformamide, terminal stopper (C-4) is propylene sulfide, terminal stopper (C-5) is glycidyl methyl ether, terminal stopper (C- 6) N-methylpyrrolidone, terminal stopper (C-7) ethyl bromohexanoate, terminal stopper (C-8) carbon dioxide, terminal stopper (C-9) methanesulfonyl chloride, terminal stopper (C-10) is 1,2-epoxycyclohexane, terminal stopper (C-11) is styrene oxide, terminal stopper (C-12) is 2-ethylhexyl glycidyl ether, terminal stopper (C-13) is bromonaphth Talene, terminal stopper (C-14) is 1-bromodecane, terminal stopper (C-15) is 2-bromoadamantane, (C-16) is propylene oxide, (C-17) is 1,2-butylene oxide , (C-18) is butyl glycidyl ether. The structures of these end terminators (C-1) to (C-18) are shown in the following formula.

The structures of the block copolymers (A-1) to (A-23) synthesized in Synthesis Examples 1 to 23 are shown in the following formula.

In the above formulas (A-1) to (A-23), n and m are each independently an integer of 2 or more. Me is a methyl group. Et is an ethyl group. Ph is a phenyl group.

<Calculation of ClogP>
The terminator ClogP used in the synthesis and the compound ClogP formed when the main chain side bond of the end group of the block copolymer is bonded to a methyl group are described in “Chemdraw Ver. 12” of CambridgeSoft. ". The ClogP of the compound formed when the main chain side bond of the terminal group of this block copolymer is bonded to the methyl group is described below as “ClogP of the terminal group linked to block (a) or block (b)”. May be written. When the terminal is unmodified (hydrogen atom), the above calculation was not performed.

Table 1 below shows the content of each repeating unit of the block copolymers (A-1) to (A-23), the end terminator used in the synthesis, ClogP of this end terminator, block (a) or block ( The terminal groups ClogP, Mw, Mn, and Mw / Mn linked to b) are shown. In Table 1 below, since the terminal terminator (C-1) is a terminal terminator that does not form a terminal group, ClogP is omitted and “−” is displayed. “4TBS” refers to 4-tert-butylstyrene. “ST” indicates styrene. “MMA” refers to methyl methacrylate.

[Synthesis Example 24] (Synthesis of Miktoarm Block Copolymer (A-24))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.55 mL (0.49 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this tetrahydrofuran, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. 11.0 mL (0.096 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.13 mL (0.49 mmol) of 1,3-bis (1-phenylethenyl) benzene was added, and 0.02 mL of methanol was further added, and the 1st arm of the Miktoarm type copolymer was added. Polymerization was completed.

The 1st arm was put into 1,000 mL of methanol, precipitated and purified, and sufficiently dried in a vacuum dryer at 60 ° C.

Next, after separately drying a 1,000 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to a nitrogen atmosphere and distilled and dehydrated was injected and cooled to −78 ° C. Thereafter, 0.55 mL (0.49 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was added to tetrahydrofuran, followed by adsorption separation with silica gel to remove the polymerization inhibitor and distillation dehydration treatment. 11.0 mL (0.096 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. Next, 4.00 mL (2.00 mmol) of a 0.5N tetrahydrofuran solution of lithium chloride was added, and the entire amount of the 1st arm that had been previously polymerized was dissolved in 100 mL of tetrahydrofuran, and added dropwise from a dropping funnel over 30 minutes to polymerize. After confirming that the system became dark red, a 2nd arm was inserted. Further, 20.3 mL (0.192 mol) of methyl methacrylate subjected to adsorption filtration with silica gel for removing the polymerization inhibitor and distilled and dehydrated was added dropwise to this solution over 30 minutes to make the polymerization system light yellow. After that, it was reacted for 120 minutes. Thereafter, 1 mL (24.7 mmol) of methanol as a terminal terminator (C-1) was injected to terminate the polymerization terminal. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove metallic Li. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer. This polymer was filtered under reduced pressure, further washed twice with methanol, and then dried under reduced pressure at 60 ° C. to obtain 38.0 g of a white block copolymer (A-24).

[Synthesis Example 25] (Synthesis of Miktoarm type block copolymer (A-25))
After drying the 500 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to distillation dehydration treatment was injected under a nitrogen atmosphere and cooled to −78 ° C. Thereafter, 0.55 mL (0.49 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) is injected into this tetrahydrofuran, and thereafter, adsorption filtration with silica gel for removing the polymerization inhibitor and distillation dehydration treatment are performed. 11.0 mL (0.096 mol) of styrene was added dropwise over 30 minutes to confirm that the polymerization system was orange. At the time of this dropwise injection, care was taken so that the internal temperature of the reaction solution did not exceed -60 ° C. After completion of the dropwise addition, the mixture was aged for 30 minutes, and then 0.13-mL (0.49 mmol) of 1,3-bis (1-phenylethenyl) benzene and 0.02 mL (0.49 mmol) of methanol were added to complete the 1st arm polymerization. It was. The 1st arm was put into 1 L of methanol, purified by precipitation, and sufficiently dried in a vacuum dryer at 60 ° C.

Next, after separately drying a 1,000 mL flask reaction vessel under reduced pressure, 200 g of tetrahydrofuran that had been subjected to a nitrogen atmosphere and distilled and dehydrated was injected and cooled to −78 ° C. Thereafter, 0.55 mL (0.49 mmol) of a 1N cyclohexane solution of sec-butyllithium (sec-BuLi) was added to tetrahydrofuran, followed by adsorption separation with silica gel to remove the polymerization inhibitor and distillation dehydration treatment. 11.0 mL (0.096 mol) was added dropwise over 30 minutes to confirm that the polymerization system was orange. Next, 2.00 mL (1.00 mmol) of a 0.5N tetrahydrofuran solution of lithium chloride was added, and a solution in which the first arm that had been previously polymerized was dissolved in 100 mL of tetrahydrofuran was added dropwise from a dropping funnel over 30 minutes. After confirming that the polymerization system became dark red, a 2nd arm was inserted. Further, 20.3 mL (0.192 mol) of methyl methacrylate subjected to adsorption filtration with silica gel for removing the polymerization inhibitor and distilled and dehydrated was added dropwise to this solution over 30 minutes to make the polymerization system light yellow. After that, it was reacted for 120 minutes. Thereafter, 0.2 mL (1.00 mmol) of 2-ethylhexyl glycidyl ether was added as a terminal terminator (C-12) and stirred for 30 minutes, and then 1 mL (24.7 mmol) of methanol was injected to terminate the polymerization terminal. It was. The reaction solution was warmed to room temperature, and the resulting reaction solution was concentrated and replaced with methyl isobutyl ketone (MIBK). Thereafter, 1,000 g of a 2% oxalic acid aqueous solution was injected and stirred, and after standing, the lower aqueous layer was removed. This operation was repeated three times to remove metallic Li. Thereafter, 1,000 g of ultrapure water was injected and stirred, and the lower aqueous layer was removed. After this operation was repeated three times to remove oxalic acid, the solution was concentrated and dropped into 500 g of methanol to precipitate a polymer. This polymer was filtered under reduced pressure, further washed twice with methanol, and then dried under reduced pressure at 60 ° C. to obtain 38.1 g of a white block copolymer (A-25).

The Miktoarm type block copolymers (A-24) and (A-25) synthesized in Synthesis Examples 24 and 25 have a structure represented by the following formula (A), and X, Y described in the formulas And Z each represent the following structure. The styrene unit contained in Y in the following formula is the block (a). The methacrylic acid ester unit contained in X and Z in the following formula is the block (b). In the following, block (b) included in X of the following formula is block X, block (a) included in Y of the following formula is block Y, and block (b) included in Z of the following formula is block Z, respectively. Sometimes called.

In the above formula, each n is independently an integer of 2 or more. * Indicates a bond that binds to a site other than X, Y and Z in the formula (A).

Table 2 below shows the end terminators used for the synthesis of the block copolymers (A-24) and (A-25), the end groups linked to ClogP, block X, block Y or block Z of this end terminator. ClogP, Mw, Mn, and Mw / Mn are shown. In Table 2 below, since the terminal terminator (C-1) is a terminal terminator that does not form a terminal group, ClogP is omitted and “−” is displayed.

[Examples 1 to 18 and Comparative Examples 1 to 7] (Preparation of pattern forming compositions (S-1) to (S-25))
The block copolymer (A-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 diameter of 40 nm to prepare a pattern forming composition (S-1). Thereafter, the same operation as in the preparation of the pattern forming composition (S-1) was conducted except that (A-2) to (A-25) were used as the block copolymers. ) To (S-25) were prepared.

[Synthesis Example 26] (Preparation of composition for forming underlayer film)
A flask equipped with a condenser and a stirrer was charged with 100 g of methyl ethyl ketone and purged with nitrogen. The flask was heated to 85 ° C., and while maintaining the temperature after the heating, 100 g of methyl ethyl ketone, 51.0 g (0.49 mol) of styrene, 49.0 g (0.49 mol) of methyl methacrylate, 3-mercapto-1,2-propane A mixed solution of 3.00 g (0.027 mol) of diol and 1.00 g (0.0061 mol) of 2,2′-azobis (2-methylpropionitrile) was added dropwise over 3 hours, and the temperature was further maintained. Polymerized for 3 hours. The obtained polymer solution was purified by precipitation with 3 L of methanol to remove residual monomers, initiators and the like. This polymer had Mw of 8,285, Mn of 5,355, and Mw / Mn of 1.54. Next, the polymer was diluted with propylene glycol monomethyl ether acetate to obtain a 10% by mass polymer solution (N-1).

A mixed solution was obtained by mixing and dissolving 150 g of this polymer solution (N-1) and 9,850 g of propylene glycol monomethyl ether acetate as a solvent. The obtained mixed solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare a composition for forming a lower layer film.

<Evaluation>
(Formation of self-assembled film)
After applying the above composition for forming a lower layer film on the surface of a 12-inch silicon wafer as a substrate so that the average thickness of the coating film to be formed is 5 nm, baking is performed at 220 ° C. for 120 seconds to form the lower layer film. Obtained substrate.

After applying the pattern-forming compositions (S-1) to (S-25) to the substrate on which the lower layer film is formed so that the average thickness of the coating film to be formed is 35 nm, the film is formed at 230 ° C. for 120 seconds. Baked. By this firing, a self-assembled film having a fingerprint pattern was formed on the substrate on which the lower layer film was formed. About the fingerprint pattern which spreads on this board | substrate, the image of 300,000 times magnification was acquired using SEM ("CG4000" of Hitachi High-Technology company).

(Fingerprint pattern evaluation 1)
Pattern Forming Composition For the pattern forming compositions (S-1) to (S-12) and (S-16) to (S22), an ordered arrangement structure (fingerprint pattern) is formed on the substrate by the following method. The self-assembled film was prepared, and the pitch of the fingerprint pattern was measured and the edge roughness was evaluated.

1. Fingerprint pattern pitch measurement Fingerprint pattern pitch measurement was performed by periodic analysis using the IMEC calculation tool built in the SEM from the image with the magnification of 300,000 times. The pitch (nm) of the fingerprint putter indicates that the smaller the value, the finer the pitch in the formed phase separation structure.

2. Fingerprint Pattern Edge Roughness (FER) Evaluation Fingerprint pattern edge roughness (FER) evaluation was analyzed from the image with a magnification of 300,000 times using a FER calculation tool built in the SEM. The FER (nm) indicates that the smaller the value is, the smaller the edge roughness of the formed fingerprint pattern is, that is, the smaller the occurrence of defects in the ordered structure in the self-assembled film, the better. FER (nm) is evaluated as “good” when it is 3.5 nm or less, and “bad” when it exceeds 3.5 nm.

Table 3 below shows the evaluation results of the pattern forming compositions (S-1) to (S-12) and (S-16) to (S22). Table 3 below also shows ClogP of the terminal group linked to the block (a) or the block (b) of the [A] block copolymer contained in the pattern forming composition.

(Fingerprint pattern evaluation 2)
With regard to the pattern forming compositions (S-13) to (S-15) and (S-23) to (S-25), except that the evaluation criteria were changed as follows, the pattern forming compositions (S- Pitch measurement and edge roughness evaluation were performed in the same manner as in 1) to (S-12) and (S-16) to (S22). FER (nm) is evaluated as “good” when 5 nm or less, and “bad” when exceeding 5 nm.

Table 4 below shows the evaluation results of the pattern forming compositions (S-13) to (S-15) and (S-23) to (S-25). Table 4 below also shows ClogP of terminal groups linked to the block (a) or the block (b) of the [A] block copolymer contained in the pattern forming composition. The block copolymers (A-24) and (A-25) each have two blocks (b). Therefore, in Table 4, ClogP of each terminal group connected to two blocks (b) is written together.

As shown in Table 3, the pattern forming compositions of Examples 1 to 14 can form a self-assembled film with fewer defects in the ordered arrangement structure than the pattern forming compositions of Comparative Examples 1 to 5. I understood. Further, as shown in Table 4, the pattern forming compositions of Examples 15 to 18 formed self-assembled films with fewer defects in the regular arrangement structure than the pattern forming compositions of Comparative Examples 6 and 7. I understood that I could do it. That is, it is judged that the pattern forming compositions of Examples 1 to 18 can be used for forming a pattern having a good shape.

According to the pattern forming composition, the pattern forming method, and the block copolymer of the present invention, a self-assembled film with few defects in a regular arrangement structure can be formed, and as a result, a pattern with a good shape can be formed. Therefore, they can be suitably used in pattern formation processes in the manufacture of various electronic devices such as semiconductor devices and liquid crystal devices that are required to be further miniaturized.

101 Substrate 102 Lower layer film 103 Pre-pattern 104 Coating film 105 Self-assembled film 105a Block (α) phase 105b Block (β) phase

Claims (14)

1. A block copolymer that forms a phase-separated structure by self-assembly, and a pattern-forming composition containing a solvent,
   The block copolymer includes a first block composed of a substituted or unsubstituted styrene unit, a second block composed of a (meth) acrylic ester unit, and a first group bonded to at least one terminal of the main chain. Have
   The pattern forming composition, wherein the first group is a monovalent group that forms a compound having a ClogP of −1 or more and 3 or less when a methyl group is bonded to the main chain side bond.
2. The first group is formed by a terminal terminator;
   The pattern forming composition according to claim 1, wherein ClogP of the terminal stopper is from -1.5 to 4.0.
3. 3. The pattern forming device according to claim 1, wherein the first group is a monovalent group that forms a compound having a ClogP of 2.5 or less when a methyl group is bonded to the main chain side bond. 4. Composition.
4. The pattern forming composition according to claim 1, 2 or 3, wherein the first group has 1 to 20 carbon atoms and 1 to 5 heteroatoms.
5. The pattern forming composition according to claim 4, wherein the first group has 6 or less carbon atoms and 2 or more heteroatoms.
6. The said 1st group of any one of Claims 1-5 containing a hydroxyl group, an amino group, a carbonyl group, a carboxyl group, a sulfonyl group, an ester group, a thiol group, an alkoxy group, or these combination. Pattern forming composition.
7. The pattern forming composition according to claim 6, wherein the first group includes at least two of a hydroxy group, an amino group, a methoxy group, and an ethoxy group.
8. The pattern forming composition according to any one of claims 1 to 7, wherein the first group is connected to the second block.
9. The pattern forming composition according to any one of claims 1 to 8, wherein the styrene unit is a styrene unit substituted with a tert-butyl group.
10. The pattern forming composition according to any one of claims 1 to 9, wherein the block copolymer is a diblock copolymer or a triblock copolymer.
11. Forming a phase-separated self-assembled film on one side of the substrate, and removing a part of the self-assembled film,
    The pattern formation method which forms the said self-assembled film with the composition for pattern formation of any one of Claims 1-10.
12. Before the self-assembled film forming step, further comprising a step of forming a lower layer film on one surface side of the substrate,
    The pattern forming method according to claim 11, wherein, in the self-assembled film forming step, the self-assembled film is formed on a surface of the lower layer film opposite to the substrate.
13. Before the self-assembled film forming step, further comprising a step of forming a pre-pattern on one surface side of the substrate,
    The pattern forming method according to claim 11 or 12, wherein, in the self-assembled film forming step, the self-assembled film is formed in a non-stacked region of the pre-pattern.
14. The pattern forming method according to claim 11, 12 or 13, wherein a line and space pattern or a hole pattern is formed.

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