阅读说明：本技术 聚合物、抗蚀剂组合物、形成有图案的基板的制造方法、以及(甲基)丙烯酸酯及其制造方法 (Polymer, resist composition, method for producing substrate having pattern formed thereon, and (meth) acrylate and method for producing same ) 是由 向井一晃 城健 加门良启 佐久间谕 安斋龙一 于 2020-03-25 设计创作，主要内容包括：一种聚合物,其包含基于式(1)所表示的单体的结构单元(1),且基于具有多环结构的单体的结构单元的含量为35摩尔％以下。式(1)中,R～(1)表示氢原子或甲基；A～(1)表示包含酯键的连接基或单键,其中,A～(1)不具有叔碳原子；Z～(1)表示包含与A～(1)结合的碳原子和-SO-(2)-而形成碳原子数3～6的含硫环式烃基的原子团。(A polymer comprising a structural unit (1) based on a monomer represented by formula (1), and the content of the structural unit based on a monomer having a polycyclic structure is 35 mol% or less. In the formula (1), R 1 Represents a hydrogen atom or a methyl group; a. the 1 Represents a linking group containing an ester bond or a single bond, wherein A 1 Having no tertiary carbon atoms; z 1 Represents a group including 1 Bound carbon atom and-SO 2 And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.)

1. A polymer comprising a structural unit (1) based on a monomer represented by the following formula (1) and having a content of the structural unit based on a monomer having a polycyclic structure of 35 mol% or less,

[ solution 1]

In the formula (1), R¹Represents a hydrogen atom or a methyl group; a. the¹Represents a linking group containing an ester bond or a single bond, wherein A¹Having no tertiary carbon atoms; z¹Represents a group including¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

2. The polymer of claim 1, further comprising a structural unit (2) having an acid-dissociable group.

3. The polymer according to claim 2, wherein the structural unit (2) comprises a structural unit (2i), and the structural unit (2i) has an acid-releasing group containing an alicyclic hydrocarbon group.

4. The polymer according to claim 3, wherein the structural unit (2) comprises a structural unit (2ii), and the structural unit (2ii) has an acid-releasing group containing a monocyclic alicyclic hydrocarbon group.

5. The polymer according to any one of claims 1 to 4, wherein the structural unit (1) is 15 mol% or more relative to the entire structural units.

6. The polymer according to any one of claims 1 to 5, further comprising a structural unit (3) having a lactone skeleton.

7. A resist composition comprising the polymer according to any one of claims 1 to 6 and a compound which generates an acid upon irradiation with active light or radiation.

8. A method of manufacturing a substrate with a pattern formed thereon, comprising: a step of applying the resist composition according to claim 7 to a surface to be processed of a substrate to form a resist film; exposing the resist film; and a step of developing the exposed resist film with a developer.

9. A method for producing a (meth) acrylic ester represented by the following formula (1x), comprising the following steps (1) and (2),

step 1: a step of obtaining a solution containing a (meth) acrylic ester (1x) represented by the following formula (1x) by an ester exchange reaction between an alcohol represented by the following formula (2x) and a (meth) acrylic ester represented by the following formula (3 x);

and a step 2: a step of adding a poor solvent to the solution containing the (meth) acrylic acid ester (1x) obtained in the step 1 to precipitate a high molecular weight substance and removing the high molecular weight substance,

[ solution 2]

In the formula (1x), R¹¹Represents a hydrogen atom or a methyl group; a. the¹¹Represents a linking group containing an ester bond or a single bond, wherein A¹¹Having no tertiary carbon atoms; z¹¹Represents a group including¹¹Bound carbon atom and-SO₂An atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group;

in the formula (2x), Z¹¹Denotes a compound containing a carbon atom bonded to a hydroxyl group and-SO₂An atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group;

in the formula (3x), R¹¹Represents a hydrogen atom or a methyl group, R¹²Represents a straight-chain or branched alkyl group having 1 to 10 carbon atoms.

10. The method for producing a (meth) acrylic ester according to claim 9, wherein a hydrocarbon solvent is used as the poor solvent in the step 2.

11. A (meth) acrylate represented by the following formula (1x), wherein the content of a high molecular weight material having a molecular weight of 5000 or more is 0.1% by mass or less,

[ solution 3]

In the formula (1x), R¹¹Represents a hydrogen atom or a methyl group; a. the¹¹Represents a linking group containing an ester bond or a single bond, wherein A¹¹Having no tertiary carbon atoms; z¹¹Represents a group including¹¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

Technical Field

The present invention relates to a polymer, a resist composition containing the polymer, a method for producing a substrate having a pattern formed using the resist composition, a (meth) acrylate, and a method for producing the (meth) acrylate.

The present application claims priority of japanese patent application No. 2019-.

Background

Sulfonyl group-containing (meth) acrylates (hereinafter, sometimes referred to as "sulfonyl group-containing (meth) acrylates") are known as sulfur-containing monomers. Polymers obtained by homopolymerizing sulfonyl group-containing (meth) acrylates or copolymers obtained by copolymerizing sulfonyl group-containing (meth) acrylates with other monomers are used, for example, as materials having high dielectric properties, materials having high refractive indices, or medical adhesives having an anti-inflammatory effect.

As a method for producing such a sulfonyl group-containing (meth) acrylate, a method utilizing a transesterification reaction between a (meth) acrylate and an alcohol is known (for example, patent document 1).

As exposure light sources for photolithography used in semiconductor manufacturing are being shortened, semiconductor devices using ArF excimer laser having a wavelength of 193nm and EUV (extreme ultraviolet) having a wavelength of 13.5nm with higher energy are being mass-produced as next-generation exposure light sources.

The resist polymer suitable for use in these exposure light sources preferably contains a polar group from the viewpoint of adhesion to a substrate and affinity for a polar solvent. As such a polar group-containing monomer, a (meth) acrylate containing a lactone group has been conventionally used.

The sulfonyl group-containing (meth) acrylate has high polarity and is expected to be also suitable as a monomer (raw material monomer) constituting a polymer for a resist.

When a polymer for a resist is produced using a sulfonyl group-containing (meth) acrylate as a monomer, if a high molecular weight material is mixed into the sulfonyl group-containing (meth) acrylate, the high molecular weight material may become an insoluble component during development, which may cause defects. Therefore, it is necessary to reduce the content of the high molecular weight material as much as possible.

As a resist composition that can suitably cope with a reduction in the wavelength of irradiation light and a reduction in the pattern size in the photolithography technique, a chemically amplified resist composition is known. The chemically amplified resist composition comprises a resist polymer in which an acid-releasing group is released by the action of an acid, and a photoacid generator.

In recent years, miniaturization of patterns has been rapidly advanced, and development of a resist material capable of further improving various lithographic characteristics such as sensitivity, pattern formability, Line Width Roughness (LWR) has been desired.

In the comparative example of patent document 2, a polymer is described which is prepared by mixing, in terms of mole ratio, 30: 20: 40: 10 in a ratio of 10, which is obtained by polymerizing a mixture of the monomer represented by the formula (a1-1-2), the monomer represented by the formula (a2-1-1), the monomer represented by the formula (a3-1-1), and the monomer represented by the formula (I-2). Further, when a resist pattern is formed using a resist composition containing the polymer and an acid generator, roughness occurs on the side of the pattern, and the Line Width Roughness (LWR) is poor.

[ solution 1]

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2007-153763

Patent document 2: japanese laid-open patent publication No. 2012-234166

Disclosure of Invention

Problems to be solved by the invention

In the case of producing a sulfonyl group-containing (meth) acrylate by the transesterification method as in patent document 1, an operation of extracting an alcohol such as methanol generated by the reaction by distillation is performed in order to incline the equilibrium toward the product side. Therefore, the reaction temperature needs to be high.

As a result of studies, the present inventors have found that a sulfonyl group-containing (meth) acrylate has high polymerizability and that a high molecular weight product is formed by polymerization of the sulfonyl group-containing (meth) acrylate or the like when exposed to a high temperature in a transesterification reaction.

Patent document 1 describes that the product is purified by recrystallization, washing, or the like, but such a method cannot sufficiently remove the high molecular weight material.

In addition, in the case of a resist composition containing a polymer having an acid-releasable group, improvement of LWR can be expected by improving the developer solubility of the polymer.

The invention aims to: to provide a polymer excellent in solubility in a developer; providing a resist composition comprising the above polymer; a method for producing a substrate having a pattern formed thereon, which comprises using the resist composition; to provide a (meth) acrylate reduced in high molecular weight; or a process for producing a (meth) acrylate ester having a reduced amount of high molecular weight substances.

Means for solving the problems

The present invention has the following aspects.

[1] A polymer comprising a structural unit (1) based on a monomer represented by the following formula (1), and the content of the structural unit based on a monomer having a polycyclic structure is 35 mol% or less.

[ solution 2]

In the formula (1), R¹Represents a hydrogen atom or a methyl group; a. the¹Represents a linking group containing an ester bond or a single bond, wherein A¹Having no tertiary carbon atoms; z¹Represents a group including¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

[2] The polymer according to the above [1], which further comprises a structural unit (2) having an acid-dissociable group.

[3] The polymer according to the above [2], wherein the structural unit (2) comprises a structural unit (2i), and the structural unit (2i) has an acid-releasable group containing an alicyclic hydrocarbon group.

[4] The polymer according to the above [3], wherein the structural unit (2) comprises a structural unit (2ii), and the structural unit (2ii) has an acid-releasing group containing a monocyclic alicyclic hydrocarbon group.

[5] The polymer according to any one of the above [1] to [4], wherein the structural unit (1) is 15 mol% or more based on the total structural units.

[6] The polymer according to any one of the above [1] to [5], further comprising a structural unit (3) having a lactone skeleton.

[7] A resist composition comprising the polymer according to any one of the above [1] to [6] and a compound which generates an acid upon irradiation with active light or radiation.

[8] A method of manufacturing a substrate with a pattern formed thereon, comprising: a step of applying the resist composition of [7] above onto a surface to be processed of a substrate to form a resist film; exposing the resist film; and a step of developing the exposed resist film with a developer.

[9] A method for producing a (meth) acrylic ester represented by the following formula (1x), comprising the following steps 1 and 2.

Step 1: a step of obtaining a solution containing a (meth) acrylic ester (1x) represented by the following formula (1x) by an ester exchange reaction between an alcohol represented by the following formula (2x) and a (meth) acrylic ester represented by the following formula (3 x).

And a step 2: and a step of adding a poor solvent to the solution containing the (meth) acrylic acid ester (1x) obtained in the step 1 to precipitate a high molecular weight substance, and removing the high molecular weight substance.

[ solution 3]

In the formula (1x), R¹¹Represents a hydrogen atom or a methyl group; a. the¹¹Represents a linking group containing an ester bond or a single bond, wherein A¹¹Having no tertiary carbon atoms; z¹¹Represents a group including¹¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

In the formula (2x), Z¹¹Denotes a compound containing a carbon atom bonded to a hydroxyl group and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

In the formula (3x), R¹¹Represents a hydrogen atom or a methyl group, R¹²Represents a straight-chain or branched alkyl group having 1 to 10 carbon atoms.

[10] The process according to [9] above, wherein a hydrocarbon solvent is used as the poor solvent in the step 2.

[11] A (meth) acrylate represented by the following formula (1x), wherein the content of a high molecular weight material having a molecular weight of 5000 or more is 0.1% by mass or less.

[ solution 4]

In the formula (1x), R¹¹Represents a hydrogen atom or a methyl group; a. the¹¹Represents a linking group containing an ester bond or a single bond, wherein A¹¹Having no tertiary carbon atoms; z¹¹Represents a group including¹¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

Effects of the invention

According to the present invention, a polymer having good solubility in a developer, a resist composition containing the polymer, and a method for producing a substrate having a pattern formed using the resist composition can be provided.

According to the present invention, a sulfonyl group-containing (meth) acrylate having a reduced high molecular weight material can be provided.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The following definitions of terms apply throughout the present specification and claims.

In the present specification, "(meth) acrylic acid" means one or both of acrylic acid and methacrylic acid.

In the present specification, the "structural unit" refers to an atomic group formed by a polymerization reaction of a monomer.

In the present specification, the monomer represented by formula (1) may be referred to as monomer (1). The same applies to the monomers represented by the other formulae.

In the present specification, a compound represented by formula (1) may be referred to as compound (1). The same applies to compounds represented by other formulae.

< Polymer >

The polymer of the present embodiment (hereinafter, also referred to as "polymer a") includes a structural unit (1) based on a monomer (1) represented by the following formula (1). The content of the structural unit based on the monomer having a polycyclic structure is 35 mol% or less with respect to the entire structural units of the polymer a.

The polymer a preferably further contains one or more kinds of structural units (2) having an acid-dissociable group. The polymer a may contain one or more kinds of other structural units other than the structural unit (1) and the structural unit (2).

The polymer A is suitably used as a resist polymer.

[ structural Unit (1) ]

The structural unit (1) is a structural unit formed by cleavage of an ethylenic double bond of the monomer (1).

[ solution 5]

In the formula (1), R¹Is a hydrogen atom or a methyl group.

A¹Is a linking group containing an ester bond or a single bond. Wherein A is¹Does not contain a tertiary carbon atom. Examples of the above-mentioned linking group include-A²-C (═ O) O-, or-a³-O-C (═ O) -. A above²、A³Is a divalent chain hydrocarbon group having 1 to 5 carbon atoms. As A²、A³The chain hydrocarbon group(s) may be linear or branched. A. the²、A³Preferably an alkylene group having 1 to 3 carbon atoms. A. the²、A³Does not contain a tertiary carbon atom.

Z¹Is composed of¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group (4-to 7-membered ring). The number of carbon atoms of the sulfur-containing cyclic hydrocarbon group is preferably 4 to 6 from the viewpoint of stability of the cyclic structure. Further, a substituent may be bonded to a carbon atom constituting the sulfur-containing cyclic hydrocarbon ring. Examples of the substituent include: carbon atomA linear or branched alkyl group having a numerator of 1 to 10, a hydroxyl group, an amino group, an aldehyde group, a chlorine group, a bromine group, and an iodine group.

The monomer (1) is preferably one in which no substituent is bonded to a carbon atom constituting the sulfur-containing cyclic hydrocarbon ring or an alkyl group having 1 to 6 carbon atoms is bonded as a substituent. The monomer of this embodiment is represented by the following formula (1').

[ solution 6]

In the formula (1'), R¹、A¹And R in the formula (1)¹、A¹The same is true.

n represents an integer of 1 to 4. And A¹The bonded heterocyclic ring is, for example, a 4-membered ring when n is 1 and a 7-membered ring when n is 4. From the viewpoint of stability and ease of synthesis, n is preferably 2.

R²Represents a substituent bonded to a carbon atom constituting the above-mentioned heterocycle. However, R²Not bound to the above-mentioned A¹Bound carbon atoms.

m R²Each independently represents an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear or branched. When m is 2 or more, a plurality of R exist in 1 molecule²May be the same or different from each other.

m is an integer of 0 or more and (n +1) or less, preferably an integer of 0 or more and n or less, more preferably 0 or 1, and most preferably 0.

As with the above A¹Examples of the group to be bonded include groups represented by the following formulae (1a) to (1 d). Wherein represents a group A¹The bond of (3).

[ solution 7]

As the monomer (1), the following modes are preferred: r¹Is a hydrogen atom or a methyl group, A¹Is a single bond, and is a single bond,and in A¹To which any one of the groups represented by the above formulae (1a) to (1d) is bonded.

Among the groups represented by the formulae (1a) to (1d), the group represented by the formula (1b) is particularly preferable from the viewpoints of stability and ease of synthesis.

The structural unit (1) contained in the polymer a may be one kind or two or more kinds.

The structural unit (1) is preferably 15 mol% or more, more preferably 20 mol% or more, and further preferably 25 mol% or more based on the total structural units of the polymer a. From the viewpoint of sensitivity and resolution, the upper limit is preferably 70 mol% or less, more preferably 60 mol% or less, and still more preferably 50 mol% or less.

For example, the structural unit (1) is preferably 15 to 70 mol%, more preferably 20 to 60 mol%, further preferably 25 to 60 mol%, and particularly preferably 25 to 50 mol% based on the total structural units of the polymer a.

[ structural Unit (2) ]

The structural unit (2) is a structural unit based on a monomer having an acid-releasable group (hereinafter, also referred to as a monomer (2)). The acid-releasable group is a group having a bond cleaved by the action of an acid, and is a group in which a part or all of the acid-releasable group is released from the polymer by cleavage of the bond. In the case of a positive chemically amplified resist composition, an acid-releasable group of a polymer in an exposed portion is reacted with an acid and released by heating after exposure, and thus the composition is soluble in an alkali developer.

The monomer (2) is preferably a (meth) acrylate compound. As the (meth) acrylate compound having an acid-releasable group, a known compound can be used.

From the viewpoint of dry etching resistance in the photolithography process, the monomer (2) preferably contains a (meth) acrylate compound having an acid-releasing group containing an alicyclic hydrocarbon group.

The alicyclic hydrocarbon group may be monocyclic or polycyclic. The alicyclic hydrocarbon group may contain a hetero atom. The heteroatom is preferably at least one selected from the group consisting of O, S and N. The number of atoms constituting the ring is preferably 5 to 22.

The resist is more preferably an acrylate having a tertiary carbon atom at the bonding site with an oxygen atom constituting an ester bond of the acrylate, from the viewpoint of excellent sensitivity and resolution of the resist. Specific examples thereof include monomers (2-1) to (2-4) of the following formulae.

In particular, when combined with the structural unit (1), the monomer (2-4) is more preferable in terms of the effect of improving the solubility of the developer.

[ solution 8]

In the formulae (2-1) to (2-4), R³¹、R³²、R³³、R³⁴Each independently represents a hydrogen atom or a methyl group.

R²¹、R²⁴、R²⁵Each independently represents an alkyl group having 1 to 5 carbon atoms. The alkyl group may be linear or branched.

R²²、R²³Each independently represents an alkyl group having 1 to 3 carbon atoms. The alkyl group may be linear or branched.

R³³¹、R³³²、R³³³、R³³⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear or branched.

X¹、X²、X³、X⁴Each independently represents an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear or branched.

n1, n2, n3 and n4 each independently represent an integer of 0 to 4. When n1, n2, n3 or n4 is 2 or more, a plurality of X's are present in 1 molecule¹、X²、X³Or X⁴May be the same or different from each other.

Z²、Z³Each independently represents-O-, -S-, -NH-or- (CH)₂) k-is provided. k represents an integer of 1 to 6.

q represents 0 or 1.

r represents an integer of 0 to 3.

The structural unit (2) contained in the polymer a may be one kind or two or more kinds.

The structural unit (2) is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and still more preferably 40 to 60 mol% based on the total structural units of the polymer a. If the lower limit value of the above range is not less than the upper limit value, good sensitivity is easily obtained, and if the upper limit value is not more than the lower limit value, good balance as a resist is easily obtained, and good adhesion to a substrate is easily obtained.

The structural unit (2) preferably includes a structural unit (2i) having an acid-releasing group containing an alicyclic hydrocarbon group. The alicyclic hydrocarbon group may be monocyclic or polycyclic. The alicyclic hydrocarbon group may contain a hetero atom. The heteroatom is preferably at least one selected from the group consisting of O, S and N. The number of atoms constituting the ring is preferably 5 to 22.

The content of the structural unit (2i) is preferably 25 mol% or more, more preferably 35 mol% or more, further preferably 50 mol% or more, and particularly preferably 75 mol% or more, based on the total number of moles of the structural unit (2). The amount may be 100 mol%. When the content of the structural unit (2i) is not less than the lower limit, the effect of improving the solubility of the developer can be easily obtained when the structural unit (1) is combined therewith.

The structural unit (2) more preferably contains a structural unit (2ii) having an acid-releasing group containing a monocyclic alicyclic hydrocarbon group. The monocyclic alicyclic hydrocarbon group preferably does not contain a hetero atom. The number of atoms constituting a ring of the monocyclic alicyclic hydrocarbon group is more preferably 5 to 8, and still more preferably 5 to 6. For example, a structural unit based on the above-mentioned monomer (2-4) is more preferable.

The content of the structural unit (2ii) is preferably 25 mol% or more, more preferably 35 mol% or more, further preferably 50 mol% or more, and particularly preferably 75 mol% or more, based on the total number of moles of the structural unit (2). The amount may be 100 mol%. When the content of the structural unit (2ii) is not less than the lower limit, the effect of improving the solubility of the developer can be easily obtained when the structural unit (1) is combined therewith.

The content of the structural unit based on the monomer having a polycyclic structure is 35 mol% or less, more preferably 30 mol% or less, with respect to the entire structural units of the polymer a. When the structural unit having a polycyclic structure is 35 mol% or less, the developer solubility of the polymer a is excellent.

[ other structural units ]

As the other structural unit, a known structural unit in a chemical amplification resist composition can be used. Examples thereof include a structural unit having a lactone skeleton and a structural unit having a hydrophilic group.

(structural unit having lactone skeleton (hereinafter, also referred to as lactone unit))

The lactone skeleton refers to a monocyclic or polycyclic atomic group containing a ring having — O — C (═ O) -. The above-mentioned ring having-O-C (═ O) -may be a ring having-C (═ O) -O-C (═ O) -.

The lactone skeleton is preferably a 4-20-membered ring, more preferably a 5-10-membered ring.

The lactone skeleton may be a single ring having only a lactone ring, or an aromatic or non-aromatic hydrocarbon ring or a heterocyclic ring may be condensed on the lactone ring.

The monomer having a lactone skeleton is preferably a (meth) acrylate compound. In particular, from the viewpoint of excellent adhesion to a substrate or the like, at least one selected from the group consisting of a (meth) acrylate having a substituted or unsubstituted δ -valerolactone ring and a (meth) acrylate having a substituted or unsubstituted γ -butyrolactone ring is preferable, and a monomer having an unsubstituted γ -butyrolactone ring is particularly preferable.

Specific examples of the monomer having a lactone skeleton include: beta- (meth) acryloyloxy-beta-methyl-delta-valerolactone, 4-dimethyl-2-methylene-gamma-butyrolactone, beta- (meth) acryloyloxy-beta-methyl-gamma-butyrolactone, alpha- (meth) acryloyloxy-gamma-butyrolactone, 2- (1- (meth) acryloyloxy) ethyl-butyrolactone-4-butyrolactone, (meth) acrylic pantolactone, 5- (meth) acryloyloxy-2, 6-norbornanolide, 8-methacryloyloxy-4-oxatricyclo [5.2.1.0^2,6]Decan-3-one, 9-methacryloyloxy-4-oxatricyclo [5.2.1.0 ]^2,6]Decan-3-one, and the like.

The lactone unit contained in the polymer a may be one kind or two or more kinds.

When the polymer a contains a lactone unit, the content of the lactone unit is preferably 10 to 70 mol%, more preferably 20 to 60 mol%, and still more preferably 30 to 50 mol% based on the total structural units of the polymer a. If the amount is within the above range, the effect of improving the adhesion to the substrate can be easily obtained.

(structural Unit having hydrophilic group (hereinafter, also referred to as hydrophilic Unit))

The term "hydrophilic group" as used herein is selected from the group consisting of-C (CF)₃)₂-OH, hydroxyl, cyano, methoxy, carboxyl and amino.

The monomer having a hydrophilic group is preferably a (meth) acrylate compound or a styrene derivative having a hydroxyl group.

Specific examples of the monomer having a hydrophilic group include: (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-n-propyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, 2-or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl-2-adamantyl (meth) acrylate, p-hydroxystyrene, dihydroxystyrene, and the like.

From the viewpoint of adhesion to a substrate or the like, 3-hydroxyadamantyl (meth) acrylate, 3, 5-dihydroxyadamantyl (meth) acrylate, 2-or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl-2-adamantyl (meth) acrylate, and the like are preferable.

The hydrophilic unit contained in the polymer a may be one kind, or two or more kinds.

The structural unit having a hydrophilic group contributes to improvement in wettability of the polymer a to a developer. The content of the structural unit having a hydrophilic group is preferably 0 to 40 mol%, more preferably 5 to 30 mol%, and still more preferably 10 to 20 mol% based on the total structural units of the polymer a. If the amount is within the above range, good balance as a resist can be easily obtained.

Preferred embodiments of the polymer a include the following embodiments (i) to (iv).

(i) A polymer comprising a structural unit (1) and a structural unit (2), wherein the structural unit (1) accounts for 15-70 mol%, the structural unit (2) accounts for 20-80 mol%, and the total amount of the structural units is 35-100 mol%.

(ii) A polymer comprises a structural unit (1), a structural unit (2) and a lactone unit, wherein the structural unit (1) accounts for 15-70 mol%, the lactone unit accounts for 10-70 mol%, the total amount of the structural unit (1) and the lactone unit accounts for 25-85 mol%, the structural unit (2) accounts for 20-80 mol%, and the total amount of the structural unit (1), the structural unit (2) and the lactone unit accounts for 45-100 mol% of the total structural units.

(iii) A polymer comprising a structural unit (1), a structural unit (2), and a hydrophilic unit, wherein the structural unit (1) is 15 to 70 mol%, the hydrophilic unit is 0 to 40 mol%, the total of the structural unit (1) and the hydrophilic unit is 15 to 80 mol%, the structural unit (2) is 20 to 80 mol%, and the total of the structural unit (1), the structural unit (2), and the hydrophilic unit is 35 to 100 mol%, based on the total of all the structural units.

(iv) A polymer comprises a structural unit (1), a structural unit (2), a lactone unit and a hydrophilic unit, wherein the structural unit (1) accounts for 15-70 mol%, the lactone unit accounts for 10-70 mol%, the hydrophilic unit accounts for 0-40 mol%, the total of the structural unit (1), the lactone unit and the hydrophilic unit accounts for 25-85 mol%, the structural unit (2) accounts for 25-80 mol%, and the total of the structural unit (1), the structural unit (2), the lactone unit and the hydrophilic unit accounts for 50-100 mol%, relative to all the structural units.

The polymer a can be produced, for example, by a solution polymerization method in which monomers are radically polymerized in the presence of a polymerization solvent using a polymerization initiator.

The weight average molecular weight of the polymer A is preferably 1,000 to 100,000, more preferably 3,000 to 50,000, and still more preferably 5,000 to 30,000.

< resist composition >

The resist composition of the present embodiment preferably contains the polymer a, a resist solvent, and a compound that generates an acid upon irradiation with active light or radiation. The polymer a may be used alone, or two or more thereof may be used in combination.

The content of the polymer a is not particularly limited, but is preferably 70 to 99.9% by mass based on the resist composition (excluding the solvent).

Examples of the resist solvent include cyclopentanone, cyclohexanone, Propylene Glycol Monomethyl Ether Acetate (PGMEA), and Propylene Glycol Monomethyl Ether (PGME). One resist solvent may be used, or two or more resist solvents may be used in combination.

The amount of the resist solvent used also depends on the thickness of the resist film to be formed, but is preferably in the range of 100 to 10,000 parts by mass per 100 parts by mass of the polymer a.

The compound that generates an acid upon irradiation with active light or radiation may be arbitrarily selected from compounds that can be used as a photoacid generator of a chemically amplified resist composition. One kind of photoacid generator may be used alone, or two or more kinds may be used in combination.

Examples of the photoacid generator include: onium salt compounds, sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds, quinonediazide compounds, diazomethane compounds, and the like.

The amount of the photoacid generator used is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the polymer a.

The resist composition may contain various additives such as a nitrogen-containing compound, an acid compound (organic carboxylic acid, oxyacid of phosphorus, or derivative thereof), a surfactant, another quencher, a sensitizer, an antihalation agent, a storage stabilizer, and a defoaming agent, as required. The additives may be those known in the art of resist compositions.

< method for manufacturing substrate having pattern >

An example of the method for manufacturing a substrate having a pattern formed thereon according to the present embodiment will be described.

First, a resist composition is applied to a surface (surface to be processed) of a substrate to be processed such as a silicon wafer by spin coating or the like. Then, the substrate to be processed coated with the resist composition is dried by baking treatment (prebaking) or the like, thereby forming a resist film on the substrate.

Next, the resist film is irradiated with light having a wavelength of 250nm or less through a photomask to form a latent image (exposure). The irradiation light is preferably KrF excimer laser, ArF excimer laser, or F₂The excimer laser and EUV excimer laser are preferably ArF excimer laser. In addition, electron beams may be irradiated.

Further, liquid immersion exposure may be performed, that is: the resist film is irradiated with light in a state where a high refractive index liquid such as pure water, perfluoro-2-butyltetrahydrofuran, perfluorotrialkylamine, or the like is interposed between the resist film and the final lens of the exposure apparatus.

After exposure, a heat treatment (post-exposure bake, PEB) is appropriately performed, and a developer is brought into contact with the resist film to dissolve a part of the resist film. In the positive type developing process, an exposed portion is dissolved and removed by an alkali developing solution.

In the polymer a, the bond of the acid-releasable group is cleaved by an acid generated by exposure, so that the dissolution rate of the exposed portion in an alkali developing solution is increased.

As the alkali developing solution, an alkaline aqueous solution may be used. For example, there may be mentioned: inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia water; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alkanolamines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; and cyclic amines such as pyrrole and piperidine.

After the development, the substrate is appropriately subjected to a rinsing process with pure water or the like. Thus, a resist pattern is formed on the substrate to be processed.

The substrate on which the resist pattern is formed is appropriately subjected to heat treatment (post-baking) to strengthen the resist, and selectively dry-etched in portions not having the resist.

After the dry etching, the resist is removed with a stripper, thereby obtaining a substrate on which a fine pattern is formed.

(meth) acrylate

The (meth) acrylate of the present embodiment is a sulfonyl group-containing (meth) acrylate (compound (1x)) represented by the following formula (1x), and is characterized in that: the content of the high molecular weight material having a molecular weight of 5000 or more is 0.1% by mass or less.

[ solution 9]

In the formula (1x), R¹¹Represents a hydrogen atom or a methyl group; a. the¹¹Represents a linking group containing an ester bond or a single bond, wherein A¹¹Having no tertiary carbon atoms; z¹¹Represents a group including¹¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

Here, the (meth) acrylate of the present embodiment in which the content of the high molecular weight material having a molecular weight of 5000 or more is defined may be sometimes referred to as a "(meth) acrylate composition" instead of a "(meth) acrylate", but in the (meth) acrylate of the present embodiment, the following may be the case: the polymer having a molecular weight of 5000 or more (hereinafter, may be simply referred to as "high molecular weight material") is contained in an extremely small amount of 0.1 mass% or less. ) Or a high molecular weight material having a molecular weight of 5000 or more is contained in a content of not more than a detection limit. In addition, since the (meth) acrylate is a (meth) acrylate which is used for various purposes and has a high molecular weight material content of 0.1 mass% or less and is prepared as a "(meth) acrylate product", the (meth) acrylate containing a very small amount or little high molecular weight material is referred to as a "(meth) acrylate" in the present embodiment.

As described above, the high molecular weight material content of 0.1 mass% or less means that the detection limit in the high molecular weight material analysis is not more than the detection limit, and includes substantially 0 mass% of the high molecular weight material content.

[ Compound (1x) ]

In the above formula (1x), A¹¹Is a linking group containing an ester bond or a single bond. Wherein A is¹¹Having no tertiary carbon atoms. As A¹¹And a linker containing an ester bond as the above A¹The same applies to the linker comprising an ester bond. From the viewpoint of ease of raw material acquisition and ease of synthesis, A¹¹Preferably a single bond.

R¹¹Is a hydrogen atom or a methyl group, preferably a methyl group.

Z¹¹Is composed of¹¹Bound carbon atom and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group (4-to 7-membered ring). The number of carbon atoms of the sulfur-containing cyclic hydrocarbon group is preferably 4 to 6 from the viewpoint of stability of the cyclic structure. Further, a substituent may be bonded to a carbon atom constituting the sulfur-containing cyclic hydrocarbon ring. Examples of the substituent include a linear or branched alkyl group having 1 to 10 carbon atoms, a hydroxyl group, an amino group, an aldehyde group, a chlorine group, a bromine group, and an iodine group.

From the viewpoint of the easiness of raw material acquisition and the stability of the compound, the sulfur-containing cyclic hydrocarbon group is more preferably a 2-sulfolane or 3-sulfolane structure in which the ring containing the sulfonyl group is a 5-membered ring, and most preferably a 3-sulfolane structure.

As the compound (1x), 3-sulfolane methacrylate is most preferable.

[ high molecular weight Material ]

In the present embodiment, the content of the high molecular weight material in the (meth) acrylate ester can be analyzed by the method described in the later-described example, and the detection limit thereof is 0.03 mass% or less.

High content in the (meth) acrylate of the present embodimentThe "quantum dot" refers to a high molecular weight product produced by polymerizing or copolymerizing a target compound (1x)) which is a sulfonyl group-containing (meth) acrylate or a compound (3x) which is a raw material for producing the compound (1x) due to its high polymerizability in step 1 of the method for producing a (meth) acrylate described later. The molecular weight is 5000 or more, and the weight average molecular weight (Mw) measured by the method described in the first example is 3X 10⁵～6×10⁵Degree of the disease. If the molecular weight is less than 5000, the polymer is soluble in a solvent, and therefore remains in the mother liquor and is removed by recrystallization or the like, and thus is not a target for removal in step 2 described later.

The content of the high molecular weight material in the (meth) acrylate of the present embodiment is 0.1% by mass or less and preferably less, preferably 0.05% by mass or less, more preferably 0.03% by mass or less, and most preferably detection limit or less.

The (meth) acrylate of the present embodiment having a reduced content of the high molecular weight material in this way can be produced by the method for producing a (meth) acrylate of the present embodiment described later.

[ use ]

The (meth) acrylate of the present embodiment having a reduced content of high molecular weight material is not affected by the high molecular weight material, and can exhibit the excellent characteristics inherent in the sulfonyl group-containing (meth) acrylate. For example, the resin composition is useful for various applications such as plastic materials, paints, and adhesives.

In particular, the sulfonyl group-containing (meth) acrylate of the present embodiment is useful as a monomer for a resist, for example, a polymer for ArF resist. By using a monomer having a reduced content of high molecular weight bodies, the lithographic characteristics of the resist polymer can be improved. For example, the solubility and developability of the resist polymer can be improved, and defects in development due to a high molecular weight material can be prevented. Further, the sulfonyl group can improve adhesion to a substrate and affinity to a polar solvent.

The sulfonyl group-containing (meth) acrylate of the present embodiment can be suitably used as the monomer (1) constituting the polymer a.

Method for producing (meth) acrylic ester

The method for producing a (meth) acrylate according to the present embodiment is a method for producing a (meth) acrylate represented by the above formula (1x), and includes the following steps 1 and 2.

Step 1: a step of obtaining a solution containing a (meth) acrylate ester represented by the above formula (1x) by an ester exchange reaction between an alcohol represented by the following formula (2x) and a (meth) acrylate ester represented by the following formula (3 x).

[ solution 10]

In the formula (2x), Z¹¹Denotes a compound containing a carbon atom bonded to a hydroxyl group and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group.

[ solution 11]

In the formula (3x), R¹¹Represents a hydrogen atom or a methyl group, R¹²Represents a straight-chain or branched alkyl group having 1 to 10 carbon atoms.

And a step 2: and a step of removing the high molecular weight material by adding a poor solvent to the solution containing the (meth) acrylic acid ester represented by the formula (1x) obtained in the step 1 to precipitate the high molecular weight material.

[ Process 1: reaction procedure

In step 1, the compound (1x) is obtained by the reaction of the alcohol compound (2x) represented by the formula (2x) with the (meth) acrylate compound (3x) represented by the formula (3 x).

In the compound (2x), Z¹¹Containing carbon atoms bound to hydroxyl groups and-SO₂And an atomic group forming a C3-6 sulfur-containing cyclic hydrocarbon group. The sulfur-containing cyclic hydrocarbon group has an excellent number of carbon atoms from the viewpoint of stability of the cyclic structureThe selection is 4-6. Further, a substituent may be bonded to a carbon atom constituting the ring of the sulfur-containing cyclic hydrocarbon group. Examples of the substituent include a linear or branched alkyl group having 1 to 10 carbon atoms, a hydroxyl group, an amino group, an aldehyde group, a chlorine group, a bromine group, and an iodine group.

From the viewpoint of easiness of raw material availability, the sulfur-containing cyclic hydrocarbon group is more preferably of a 2-sulfolane or 3-sulfolane structure having a 5-membered ring containing a sulfonyl group. Of these, 3-sulfolane structure is most preferred.

As the compound (2x), 3-hydroxysulfolane is most preferable.

In the compound (3x), R¹¹Is a hydrogen atom or a methyl group, preferably a methyl group.

R¹²Is a straight-chain or branched alkyl group having 1 to 10 carbon atoms. Examples of the straight-chain or branched alkyl group having 1 to 10 carbon atoms include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, and the like.

Since it is necessary to remove the alcohol derived from the raw material ester by distillation in the transesterification reaction, it is preferable that the boiling point of the by-product alcohol produced in the transesterification reaction is low. From this viewpoint, R¹²Preferably methyl.

That is, as the compound (3x), methyl acrylate or methyl methacrylate is preferable.

In step 1, the compound (1x) is produced by a transesterification reaction. The conditions for the transesterification reaction are not particularly limited, and the reaction may be carried out by a known method. For example, Japanese patent application laid-open No. 2007-153763 discloses a method of obtaining 3-sulfolane methacrylate by reacting 3-hydroxysulfolane with methyl methacrylate.

In order to obtain the compound (1x) in good yield, the compound (2x) is preferably used after dehydration. As a method of dehydration, a method of dissolving the compound (2x) in an organic solvent, heating the solution, and removing water by azeotropy between the organic solvent and water is preferable. As the azeotropic organic solvent, benzene, toluene, ethylbenzene, methyl ethyl ketone, 1, 4-dioxane, hexane, cyclohexane, or the like can be used. In the case where the compound (3x) is azeotroped with water, the compound (2x) may be dissolved in the compound (3x) and dehydrated by azeotropy.

A catalyst may or may not be used in the transesterification reaction. For obtaining the compound (1x) in good yield, a catalyst is preferably used. When a catalyst is used, a titanium catalyst or a tin catalyst can be used. As the titanium catalyst, there can be mentioned: tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetra-isopropoxytitanium, tetra-n-butoxytitanium, tetra-isobutoxytitanium, and the like. Examples of the tin catalyst include: di-n-butyltin oxide, di-n-octyltin oxide, di-2-ethylhexyltin oxide, and the like. From the viewpoint of the removability of the catalyst after the reaction, a titanium catalyst is preferably used.

The amount of the catalyst to be used is preferably 0.001 mol or more, more preferably 0.01mol or more based on 1mol of the compound (2x) from the viewpoint of efficiently obtaining the compound (1 x). In addition, the amount of the catalyst used is preferably 0.05 mol or less, more preferably 0.03 mol or less, based on 1mol of the compound (2x) from the viewpoints of catalyst removal and cost. The transesterification catalyst may be added at once or separately.

For example, the amount of the catalyst to be used is preferably 0.001 to 0.05 mol, and more preferably 0.01 to 0.03 mol, based on 1mol of the compound (2 x).

In the transesterification reaction, the amount of the compound (3x) to be used is not particularly limited, but is preferably 0.5 mol or more, more preferably 0.8 mol or more, and further preferably 1.0mol or more based on 1mol of the compound (2x) from the viewpoint of obtaining the compound (1x) in a good yield. In particular, when the by-product alcohol is removed by azeotropy with the compound (3x), if the amount of the compound (3x) used is small, the by-product alcohol cannot be sufficiently removed, and thus the reaction rate may be lowered. In addition, the amount of the compound (3x) used is preferably 12 moles or less, more preferably 10 moles or less, and even more preferably 8 moles or less, based on 1 mole of the compound (2x), from the viewpoints of the pot efficiency of the transesterification reaction and the suppression of the load on the treatment step after the reaction.

For example, the amount of the compound (3x) to be used is preferably 0.5 to 12 moles, more preferably 0.8 to 10 moles, and still more preferably 1 to 8 moles, based on 1 mole of the compound (2 x).

In order to inhibit the polymerization of the compound (3x) and the compound (1x) in the reaction system, it is preferable to add a polymerization inhibitor. The kind of the polymerization inhibitor is not particularly limited, and one kind may be used, or two or more kinds may be used.

As the polymerization inhibitor, there may be mentioned: phenol compounds such as hydroquinone, p-methoxyphenol, 2, 4-dimethyl-6-tert-butylphenol, 2, 6-tert-butyl-4-methylphenol, tert-butylcatechol, and 2, 6-di-tert-butyl-4-methylphenol; amine compounds such as N, N-diisopropyl-p-phenylenediamine, N- (1, 3-dimethylbutyl) -N' -phenyl-p-phenylenediamine, and N, N-di-2-naphthyl-p-phenylenediamine; and N-oxyl compounds such as 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-N-oxyl, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine-N-oxyl, 4-acetamide-2, 2,6, 6-tetramethylpiperidine-N-oxyl, and bis (1-oxyl-2, 2,6, 6-tetramethylpiperidin-4-yl) sebacate.

In addition, in order to prevent polymerization, it is also preferable to foam an oxygen-containing gas in the transesterification reaction. The amount of the oxygen-containing gas to be introduced can be appropriately set. Air is particularly preferably used as the oxygen-containing gas.

The temperature of the transesterification reaction is not particularly limited, but is preferably 30 ℃ or higher, more preferably 60 ℃ or higher, in order to remove the by-produced alcohol and increase the reaction rate. In order to inhibit polymerization of the compound (3x) or the compound (1x), it is preferably 160 ℃ or lower, and more preferably 140 ℃ or lower.

For example, the temperature of the transesterification reaction is preferably 30 to 160 ℃, and more preferably 60 to 140 ℃.

The time for the transesterification reaction is preferably 0.5 hours or more, more preferably 1 hour or more, from the viewpoint of efficiently obtaining the compound (1 x). In order to inhibit polymerization of the compound (3x) or the compound (1x), it is preferably 50 hours or less, and more preferably 30 hours or less.

For example, the time for the transesterification reaction is preferably 0.5 to 50 hours, and more preferably 1 to 30 hours.

As the post-treatment after the reaction, when a catalyst is used, an operation of deactivating the catalyst may be performed. Particularly when the compound (1x) is used for a resist, it is preferable to reduce the incorporation of a metal as much as possible. Therefore, in the case of using a metal as a catalyst, it is preferable to deactivate and remove the catalyst. Examples of the method include the following methods.

That is, the reaction solution was cooled to about 70 ℃ or lower while stirring, and then water, an adsorbent, and diatomaceous earth as a filter aid were added in amounts equal to or more than the amount of the catalyst added to deactivate the catalyst as a metal oxide and precipitate the metal oxide. And after the addition is finished, stirring is continued for 1-5 hours. The precipitated metal oxide can be removed by pressure filtration, reduced pressure filtration, or the like.

[ step 2: refining procedure

In step 2, a poor solvent is added to the solution containing the compound (1x) produced in step 1 to precipitate a high molecular weight substance, and the precipitated high molecular weight substance is removed. The precipitation of the high molecular weight substance by the poor solvent in step 2 is different from the washing operation and the recrystallization operation described later, in which the high molecular weight substance is not precipitated, in that the high molecular weight substance is precipitated without precipitating the compound (1 x).

The poor solvent to be added is not particularly limited, and there may be mentioned: hydrocarbon solvents such as pentane, hexane, heptane, cyclopentane, cyclohexane, octane, toluene, xylene, and the like; ether solvents such as diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, and dioxane; ester-based solvents such as ethyl acetate, butyl acetate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and butyl methacrylate; and alcohol solvents such as methanol, ethanol, and 2-propanol. The poor solvent may be used alone or in combination of two or more.

More preferably, a hydrocarbon solvent having a low solubility of the high molecular weight material is used. Among them, from the viewpoint of easy removal by distillation or the like, a saturated hydrocarbon solvent having 5 to 7 carbon atoms such as pentane, hexane, heptane or the like is more preferable.

The amount of the poor solvent to be added may be appropriately determined depending on the amount and solubility of the high molecular weight material. In order to reduce the solubility of the high molecular weight material and precipitate it, the amount of the compound (2x) used in the reaction is preferably 0.2 times by mass or more, and more preferably 0.5 times by mass or more. From the viewpoint of economy and pot efficiency, the amount of the compound (2x) to be used in the reaction is preferably 5 times or less by mass, and more preferably 3 times or less by mass.

For example, the amount of the poor solvent added is preferably 0.2 to 5 times by mass, and more preferably 0.5 to 3 times by mass, based on the mass of the compound (2 ×) used in the reaction.

The method for removing the precipitated high molecular weight substance is not particularly limited, and examples of the distillation residue include separation, pressure filtration, reduced pressure filtration, and centrifugation. An appropriate method may be appropriately used in consideration of the boiling point, properties, scale (scale), amount of the high molecular weight substance, and the like of the compound (1 x). In order not to generate a high molecular weight material during the removal, pressure filtration, reduced pressure filtration, and centrifugal separation are preferably used as a method without heating.

After the separation of the high molecular weight material, the poor solvent may be removed by concentration by reduced pressure distillation or the like.

The step 2 may include purification of the compound (1x) as required. Examples of the method for purifying compound (1x) include washing, heat treatment, filtration, distillation, recrystallization, and the like. These may be carried out alone or in combination of two or more. The purification may be performed before, after, or both of the step of precipitating the high molecular weight substance.

Since the compound (2x) has a sulfonyl group, it is highly polar and easily soluble in water. Therefore, the compound (2 ×) can be removed into the water layer by washing with water or an aqueous solution in which 5 to 30 mass% of an inorganic salt such as sodium chloride, ammonium sulfate, sodium sulfate, or the like is dissolved as a washing liquid. The number of times of cleaning can be appropriately determined. From the viewpoint of reducing the incorporation of the metal into the compound (1x), it is preferable to include a step of washing with water.

The washing may be performed without adding a solvent, or may be diluted with a solvent. In order to reduce hydrolysis of the compound (1 ×) and outflow into the aqueous layer, it is preferable to dilute the compound with a solvent. The solvent is not particularly limited, and examples thereof include: hydrocarbon solvents such as pentane, hexane, heptane, cyclopentane, cyclohexane, octane, toluene, xylene, and the like; ether solvents such as diethyl ether, diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran, and dioxane; and ester-based solvents such as ethyl acetate, butyl acetate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and butyl methacrylate. These solvents may be used alone or in combination of two or more. The amount of the solvent to be used may be appropriately determined depending on the solubility of the compound (1x) and the amount of the cleaning solution.

When the compound (1x) is purified by distillation, it is preferable to add a polymerization inhibitor and perform the purification in a vacuum of 1.3kPa (10mmHg) or less while appropriately introducing an oxygen-containing gas such as air. In particular, from the viewpoint of a small thermal history, it is preferably carried out by a method such as thin film distillation.

In the case of purifying compound (1x) by recrystallization, the following solvents were used: a solvent in which the compound (1x) is dissolved at room temperature to 40 ℃ and cooled to room temperature or lower to precipitate crystals. As the solvent used for recrystallization, an alcohol-based solvent such as methanol, ethanol, isopropanol, butanol, etc.; ester solvents such as ethyl acetate, butyl acetate, and methyl methacrylate; ether solvents such as diethyl ether, diisopropyl ether and tert-butyl methyl ether may be used alone or in combination. In order to increase the recovery rate of recrystallization, a hydrocarbon solvent such as hexane, octane, heptane, or the like, in which crystals are difficult to dissolve, may be used in combination with the alcohol solvent, the ester solvent, or the ether solvent; halogen-based solvents such as chloroform, dichloroethane and dichloromethane; water, and the like. The alcohol solvent is preferably used alone, because the solvent can be easily reused. Further, from the viewpoint of optimizing the slurry concentration at the time of crystal deposition and improving the recovery rate, a mixed solvent of an alcohol-based solvent and a hydrocarbon-based solvent is more preferable.

From the viewpoint of suppressing an increase in viscosity and improving process passability, the slurry concentration is preferably 25% by mass or less, and more preferably 20% by mass or less. From the viewpoint of economy and pot efficiency, the amount of the organic solvent is preferably 5% by mass or more, and more preferably 10% by mass or more.

For example, the slurry concentration is preferably 5 to 25 mass%, more preferably 10 to 20 mass%.

In the recrystallization, it is preferable to dissolve the compound (1x) in a solvent at 30 ℃ or higher, slowly cool the solution, and promote crystallization by adding a seed crystal when the internal temperature becomes 5 to 10 ℃. The internal temperature rises due to latent heat accompanying crystallization, but crystals are separated when the internal temperature is lowered to 10 ℃ or lower by cooling. The separation of the crystals can be performed using a centrifugal filter, a pressure filter, or the like. After the separation of the crystals, washing is carried out by a solvent.

After recrystallization, the crystals are preferably isolated using a solvent mixed or dissolved in water, and then the wet crystal cake is washed with water. This enables removal of most of the solvent adhering to the crystals, and even if the temperature of the wet crystals rises to around room temperature, there is almost no possibility of dissolution.

Examples

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

Example (I)

The reaction tracking was performed by gas chromatography.

< method for measuring weight average molecular weight >

The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the polymer were determined by gel permeation chromatography in terms of polystyrene. Tetrahydrofuran (THF) was used as the eluent.

< method for measuring copolymerization composition ratio >

For the polymers obtained in the respective examples, the process is carried out by¹The composition ratio (unit: mol%) of the structural units based on each monomer was determined by H-NMR measurement.

In this measurement, a sample solution (solvent is deuterated chloroform) of about 5 mass% was put into a sample tube having a diameter of 5mm phi by using an ECS-400 superconducting FT (Fourier transform) -NMR apparatus manufactured by Nippon electronics Co., Ltd., and the sample solution was accumulated 64 times in a single pulse mode at an observation frequency of 400 MHz. The measurement was carried out at a measurement temperature of 60 ℃.

< method for evaluating solubility of developing solution (method for measuring turbidity) >

Turbidity Th (80) and turbidity Tm (80) were measured by the following measurement methods using a turbidity meter (product name: TB200, manufactured by Orbeco-Hellige Co.). Th (80) is an index of solubility in a low-polarity organic solvent, and Tm (80) is an index of solubility in a high-polarity organic solvent. Higher turbidity means lower solubility in organic solvents. In other words, the higher the haze, the higher the polarity, and the solubility in an alkali developing solution tends to be excellent.

[ method for measuring turbidity Th (80) ]

(1) A polymer to be measured was dissolved in 75/25 mass% of a mixed solvent of PGMEA/γ -butyrolactone, to prepare a PGMEA/γ -butyrolactone solution (hereinafter, referred to as a sample solution) having a concentration of 20 mass%.

(2) N-heptane was added to the sample solution prepared in the above (1) to prepare a mixed solution, and the amount of n-heptane added to the sample solution (Xh mass%) was determined so that the turbidity of the mixed solution became 10 NTU.

(3) An amount of 80% of n-heptane corresponding to the Xh mass% was added to the sample solution prepared in the above (1), and the mixture was stirred at 25 ℃ for 4 hours to obtain a measurement solution.

(4) The turbidity of the measurement solution at 25 ℃ was defined as Th (80).

[ method for measuring turbidity Tm (80) ]

(5) Methanol was added to the sample solution prepared in (1) to prepare a mixed solution, and the amount of methanol added to the sample solution (Xm mass%) was determined so that the turbidity of the mixed solution became 5.0 NTU.

(6) Methanol was added to the sample solution prepared in (1) in an amount of 80% by mass of Xm, and the mixture was stirred at 25 ℃ for 4 hours to obtain a measurement solution.

(7) The turbidity of the measurement solution at 25 ℃ was defined as Tm (80).

The following monomers (m1) to (m7) were used in the following examples and comparative examples.

[ solution 12]

[ solution 13]

[ example 1-1]

In a flask equipped with a nitrogen gas inlet, a stirrer, a condenser and a thermometer, 8.1 parts by mass of PGMEA and 32.5 parts by mass of γ -butyrolactone were placed under nitrogen atmosphere, and the temperature of the hot water bath was increased to 80 ℃ while stirring. Then, the following mixture 1 was added dropwise to the flask over 4 hours using a dropping funnel, and the temperature of 80 ℃ was further maintained for 3 hours to obtain a reaction solution.

(composition of mixture 1)

8.17 parts by mass (20 mol%) of the monomer (m1),

10.20 parts by mass (30 mol%) of the monomer (m2),

13.44 parts by mass (40 mol%) of the monomer (m3),

4.72 parts by mass (10 mol%) of the monomer (m4),

solvent: 8.9 parts by mass of PGMEA, 35.7 parts by mass of gamma-butyrolactone, and

polymerization initiator: 3.91 parts by mass of dimethyl-2, 2' -azobisisobutyrate (Wako pure chemical industries, Ltd., V601 (trade name)).

The obtained reaction solution was added dropwise to a mixed solvent of methanol and water in an amount of about 10 times the volume of the reaction solution (methanol/water: 80/20 volume ratio) while stirring, to obtain a white precipitate. The precipitate was separated by filtration, and the precipitate was again charged into methanol in the same amount as above, and washed with stirring. Then, the washed precipitate was separated by filtration to obtain a wet polymer powder, and the wet polymer powder was dried at 60 ℃ for about 36 hours under reduced pressure to obtain a dry powdery polymer.

The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the obtained polymer are shown in table 1 (the same applies below).

For the obtained polymer, the turbidity was measured by the above-mentioned method. The results are shown in table 1 (the same applies hereinafter).

The copolymerization composition ratio shown in table 1 is a charge ratio, and the results of measurement of the copolymerization composition ratio of the obtained polymer by the above-mentioned method are: 20.2 mol% of the structural unit (m1), 30.1 mol% of the structural unit (m2), 39.7 mol% of the structural unit (m3), and 10.0 mol% of the structural unit (m4) were substantially the same as the charge ratio.

15.0 parts by mass of the polymer obtained in the form of a dry powder, 105.0 parts by mass of PGMEA, and 0.3 parts by mass of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator were mixed to prepare a uniform solution, which was then filtered through a membrane filter having a pore size of 0.1 μm to prepare a resist composition.

Examples 1-2 and comparative examples 1-1

The monomer feed composition in example 1-1 was changed to that shown in Table 1. The polymer was produced and evaluated in the same manner as in example 1-1.

Further, using the obtained polymer, a resist composition was produced in the same manner as in example 1-1.

Comparative examples 2-1 and 2-2

The monomer feed composition in example 1-1 was changed to that shown in Table 1. The polymer was produced and evaluated in the same manner as in example 1-1.

Further, using the obtained polymer, a resist composition was produced in the same manner as in example 1-1.

Examples 3-1, 4-1 and comparative example 3-1

The monomer feed composition in example 1-1 was changed to that shown in Table 1. The polymer was produced and evaluated in the same manner as in example 1-1.

Further, using the obtained polymer, a resist composition was produced in the same manner as in example 1-1.

[ Table 1]

As shown in Table 1, the polymers of examples 1-1, 1-2, 3-1 and 4-1 had high polarity because of their high haze, and were excellent in solubility in an alkaline developing solution.

Example (II)

In the following examples and comparative examples, 3-hydroxysulfolane was synthesized by the method described in patent document 1 (Japanese patent laid-open No. 2007-153763).

As methyl methacrylate, Acrylic Ester M (trade name) manufactured by Mitsubishi chemical was used.

Titanium tetrabutoxide was used as a product manufactured by Kanto chemical Co.

Examples of 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-N-oxyl include Fuji film and Wako pure chemical industries.

Celite 545 (trade name) manufactured by Takeda chemical Co., Ltd was used as diatomaceous earth.

The reaction rate in the transesterification reaction was calculated from the following formula based on the peak area in the measurement by gas chromatography (hereinafter referred to as "GC". device: Agilent 6890GC of Agilent technologies, Ltd., column: HP-5).

Reaction rate (%) - (A/B). times.100

Here, a represents the quantitative value of compound (1) based on the standard curve, and B represents the sum of the quantitative values of compound (1) and compound (2) based on the standard curve.

The content of the high molecular weight substance was calculated as a quantitative value based on a standard curve from peak area values in measurement by gel permeation chromatography (hereinafter referred to as "GPC". device: Tosoh corporation HLC-8320GPC, column: Shodex LF-804 (3), eluent: tetrahydrofuran).

The weight average molecular weight (Mw) of the high molecular weight material was calculated from the elution time in the measurement of GPC (apparatus: Tosoh corporation HLC-8320GPC, column: Shodex LF-804 (3), eluent: tetrahydrofuran) using a standard curve based on standard polystyrene.

< example 5-1 >)

[ Process 1]

In a 100mL glass flask equipped with Dean Stark, 20.1g (147mmol) of 3-hydroxysulfolane, 103.1g (1.0mol) of methyl methacrylate, and 0.12g of 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl (hereinafter referred to as "HO TEMPO") were charged, and the mixture was refluxed to remove water from the solution by Dean Stark. Then, 1.5g (4mmol) of titanium tetrabutoxide was added, and the reaction solution was heated and refluxed at an internal temperature of 100 to 110 ℃ while blowing air at 20 mL/min. Methanol generated by the reaction was removed by azeotropy with methyl methacrylate using dean-stark while stirring for 2.5 hours. During this time, 45.8g of a mixture of methanol and methyl methacrylate was withdrawn. The reaction rate by GC analysis was 91%. Then, after cooling to room temperature, 1.6g of water and 6.9g of diatomaceous earth were added, and the mixture was stirred for 1 hour, and the obtained mixture was filtered under reduced pressure using a filter paper. GPC analysis and Mw measurement revealed that Mw was 1.15% by mass, i.e., Mw was 4.6X 10⁵The high molecular weight polymer of (1).

[ Process 2]

To the obtained filtrate, 30mL of toluene and 15mL of water were added to wash the organic layer, and the aqueous layer was drained using a separatory funnel. Then, 20mL of water was added to wash the organic layer, and the aqueous layer was drained using a separatory funnel. Subsequently, 24g of hexane was added thereto and stirred to precipitate a gel-like high molecular weight material. After magnesium sulfate was added and dried, the filtrate was filtered under reduced pressure using filter paper, and the filtrate was concentrated using an evaporator to obtain 22.1g of crude 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

66.2g of 2-propanol and 33.1g of heptane were added to the obtained crude 3-sulfolane methacrylate, and the mixture was cooled with stirring, and when the temperature was lower than 20 ℃, seed crystals were added to precipitate crystals. The obtained crystals were filtered, washed with heptane and water, and dried under reduced pressure to obtain 12.9g of purified 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

< example 5-2 >

[ Process 1]

In a 3L glass flask equipped with a stirrer, a thermometer and dean Stark, 351g (2.6mol) of 3-hydroxysulfolane, 1770g (17.7mol) of methyl methacrylate and 2.2g of HO TEMPO were charged, and the mixture was refluxed and then the water in the solution was removed by dean Stark. Then, 26g (77mmol) of titanium tetrabutoxide was added, and the reaction solution was heated and refluxed at an internal temperature of 100 to 110 ℃ while blowing air at 20 mL/min. Methanol generated by the reaction was removed by azeotropy with methyl methacrylate using dean-stark while stirring for 8 hours. The amount of the mixture of methanol and methyl methacrylate withdrawn during this period was 902 g. The reaction rate by GC analysis was 88%. Then, after cooling to room temperature, 28g of water and 121g of diatomaceous earth were added thereto, and the mixture was stirred for 1 hour, and the obtained mixture was filtered under reduced pressure using filter paper. GPC analysis and Mw measurement revealed that Mw of 0.08% by mass was 4.0X 10⁵The high molecular weight polymer of (1).

[ Process 2]

To the filtrate obtained was added 900mL of toluene and 200mL of water to wash the organic layer, and 242g of the aqueous layer was separated. Then, 200mL of water was added to wash the organic layer, and 204g of the aqueous layer was separated. Then, 650mL of hexane was added thereto and stirred to precipitate a gel-like high molecular weight material. After magnesium sulfate was added to dry, the filtrate was filtered under reduced pressure using filter paper, and the filtrate was concentrated using an evaporator, to obtain 406g of crude 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

The crude 3-sulfolane methacrylate thus obtained was kept at 26 ℃ while adding 1181g of 2-propanol and 592g of heptane, and cooled with stirring, and when the temperature was lower than 20 ℃, seed crystals were added to precipitate crystals. The obtained crystals were filtered, washed with heptane and water, and dried under reduced pressure to obtain 219g of purified 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

< example 5-3 >

[ Process 1]

In a 10L separable glass flask equipped with a stirrer, a thermometer and dean Stark, 1394g (10.2mol) of 3-hydroxysulfolane, 7269g (72.6mol) of methyl methacrylate and 4.4g of HO-TEMPO were charged, and the mixture was refluxed and the water content in the solution was removed by dean Stark. Subsequently, 70g (0.2mol) of titanium tetrabutoxide was added, and the reaction solution was heated and refluxed at an internal temperature of 100 to 110 ℃ while blowing air at 20 mL/min. Methanol generated by the reaction was removed by azeotropy with methyl methacrylate using dean-stark while stirring for 6 hours. The amount of the mixed solution of methanol and methyl methacrylate withdrawn during this period was 1477 g. The reaction rate by GC analysis was 67%. Then, the reaction mixture was cooled to 70 ℃ or lower, 35g (0.1mol) of titanium tetrabutoxide was added thereto, and the reaction mixture was heated while blowing air at 20mL/min and refluxed at an internal temperature of 100 to 110 ℃. Methanol generated by the reaction was removed by azeotropy with methyl methacrylate using dean-stark while stirring for 7.5 hours. The amount of the mixed solution of methanol and methyl methacrylate withdrawn during this period was 2081 g. The reaction rate by GC analysis was 87%. The reaction mixture was cooled to 70 ℃ or lower again, 3.5g (0.01mol) of titanium tetrabutoxide was added thereto, and the reaction mixture was heated while blowing air at 20mL/min and refluxed at an internal temperature of 100 to 110 ℃. After stirring for 3.5 hours, the reaction rate by GC analysis was 87%. The amount of the mixed solution of methanol and methyl methacrylate withdrawn during this period was 525 g. Then, after cooling to 70 ℃ or lower, 16g of water and 483g of diatomaceous earth were added, and the mixture was stirred for 1 hour, and the obtained mixture was pressure-filtered through filter paper. GPC analysis and Mw measurement revealed that Mw of 0.21% by mass was 0.2X 10⁵The high molecular weight polymer of (1).

[ Process 2]

To the filtrate obtained was added 3000g of toluene, and 812g of water was added to wash the organic layer, and 965g of an aqueous layer was separated. Then, 837g of water was added to wash the organic layer, and 852g of the aqueous layer was separated. Then, 2020g of hexane was added thereto and stirred to precipitate a gel-like high molecular weight material. The high molecular weight material was removed by pressure filtration using filter paper, and the filtrate was concentrated using an evaporator to obtain 1641g of crude 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

The obtained crude 3-sulfolane methacrylate was kept at 22 ℃ while adding 4690g of 2-propanol and 2380g of heptane, and cooled with stirring, and when the temperature was lower than 17 ℃, seed crystals were added to precipitate crystals. The obtained crystals were filtered, washed with heptane and water, and dried under reduced pressure to obtain 1000g of purified 3-sulfolane methacrylate. The result of GPC analysis showed that no high molecular weight product having a molecular weight of 5000 or more was detected.

< comparative example 5-1 >

Process 1 was performed in the same manner as in example 5-1, except for using 20.0g (147mmol) of 3-hydroxysulfolane, 118.0g (1.2mol) of methyl methacrylate, 0.12g of HO-TEMPO, and 0.7g (4mmol) of tetraethoxytitanium. GPC analysis and Mw measurement of the filtrate revealed that Mw was 0.29% by mass, i.e., Mw was 4.8X 10⁵The high molecular weight polymer of (1).

To the obtained filtrate, 30mL of toluene and 15mL of water were added to wash the organic layer, and the aqueous layer was drained using a separatory funnel. Then, 15mL of water was added to wash the organic layer, and the aqueous layer was drained using a separatory funnel. After magnesium sulfate was added to dry, the filtrate was filtered under reduced pressure using filter paper, and the filtrate was concentrated using an evaporator to obtain 25.6g of crude 3-sulfolane methacrylate. As a result of GPC analysis, 0.22 mass% of a high molecular weight material was detected. As a result, 38.9g of 2-propanol was added to the crude 3-sulfolane methacrylate to precipitate a gel-like high-molecular-weight product, and 38.4g of 2-propanol and 38.5g of heptane were added as it is, and when the temperature was lower than 20 ℃, a seed crystal was added to conduct recrystallization to obtain 21.3g of purified 3-sulfolane methacrylate. As a result of GPC analysis, 0.11 mass% of a high molecular weight material having a molecular weight of 5000 or more was detected.

In these examples, the results of Mw measurement and GPC analysis of the high molecular weight material in each step are shown in table 2 below.

In table 2, the analysis results after the completion of the reaction are shown after step 1, the analysis results after the concentration by adding a poor solvent to precipitate and remove a high molecular weight substance after step 2, and the analysis results of the purified 3-sulfolane methacrylate obtained by recrystallization purification after recrystallization are shown.

N.d. indicates no detection.

[ Table 2]

As shown in the results in Table 2, the 3-sulfolane methacrylate obtained in examples 5-1 to 5-3 was a high-purity product in which a high-molecular-weight product having a molecular weight of 5000 or more was not detected.

On the other hand, in comparative example 5-1 in which step 2 was not performed, 0.11 mass% of a high molecular weight material having a molecular weight of 5000 or more was contained in the obtained 3-sulfolane methacrylate.

From these results, it was found that the content of the high molecular weight material having a molecular weight of 5000 or more can be reduced to 0.1% by weight or less by removing the high molecular weight material by precipitating the high molecular weight material with a poor solvent in the purification step.

Industrial applicability

According to the present embodiment, a polymer having good solubility in a developer, a resist composition containing the polymer, and a method for manufacturing a substrate having a pattern formed using the resist composition can be obtained.

According to the present embodiment, a sulfonyl group-containing (meth) acrylate having a reduced high molecular weight material can be obtained.

The (meth) acrylate of the present embodiment has a reduced content of high molecular weight bodies, and is useful for various applications such as plastics, paints, and adhesives. In addition, the monomer suitable for forming a polymer for a resist is useful for improving lithographic characteristics.