Polymer, resist composition, method for manufacturing substrate having pattern formed therein, and (METH)acrylic ester and production method therefor

Abstract

To provide a polymer having excellent solubility in a developer, to provide a resist composition including the polymer, to provide a method for manufacturing a substrate having a pattern therein using the resist composition, to provide a (meth)acrylic ester in which a high-molecular-weight substance is reduced, and to provide a production method for a (meth)acrylic ester in which a high-molecular-weight substance is reduced.SOLUTION: Provided is a polymer including a constituent unit (1) based on a monomer represented by Formula (1), in which a content of a constituent unit based on a monomer having a polycyclic structure is 35 mol% or less. In Formula (1), R1 represents a hydrogen atom or a methyl group, A1 represents a linking group including an ester bond, or a single bond, where A1 has no tertiary carbon atom, and Z1 represents an atomic group forming a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms, which includes a carbon atom bonded to A1, and -SO2-.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polymer, a resist composition containing the polymer, a method for producing a substrate having a pattern using the resist composition, a (meth)acrylic acid ester, and a method for producing the (meth)acrylic acid ester. This application claims priority based on Japanese Patent Application Nos. 2019-059909, 2019-059910, and 2019-060490 filed in Japan on March 27, 2019, and incorporates the contents herein by reference.

Background Art

[0002] A (meth)acrylic acid ester containing a sulfonyl group (hereinafter sometimes referred to as "sulfonyl group-containing (meth)acrylic acid ester") is known as a sulfur-containing monomer. A polymer obtained by homopolymerizing a sulfonyl group-containing (meth)acrylic acid ester or a copolymer obtained by copolymerizing with another monomer is used, for example, as a material having high dielectric properties, a material having a high refractive index, or a medical adhesive having an anti-inflammatory effect.

[0003] As a method for producing such a sulfonyl group-containing (meth)acrylic acid ester, a method by transesterification of a (meth)acrylic acid ester and an alcohol is known (for example, Patent Document 1).

[0004] The exposure light source for lithography used in semiconductor manufacturing has been shifting to shorter wavelengths, and mass production of semiconductor elements using an ArF excimer laser with a wavelength of 193 nm or EUV (extreme ultraviolet light) with a wavelength of 13.5 nm, which has higher energy, as the next-generation exposure light source is progressing. A polymer for resist applied to these is desirably a polymer containing a polar group from the viewpoints of adhesion to a substrate and affinity for a polar solvent. Conventionally, a (meth)acrylic acid ester containing a lactone group has been frequently used as such a monomer containing a polar group. Sulfonyl group-containing (meth)acrylic acid esters have high polarity and are expected to be applicable as monomers (raw material monomers) constituting polymers for resists.

[0005] When producing a polymer for a resist using a sulfonyl group-containing (meth)acrylic acid ester as a monomer, if a high molecular weight substance is mixed in the sulfonyl group-containing (meth)acrylic acid ester, the high molecular weight substance may become an insoluble component during development and defects may occur. Therefore, it is necessary to reduce the content of the high molecular weight substance as much as possible.

[0006] As a resist composition that can suitably respond to the shortening of the wavelength of irradiation light and the miniaturization of patterns in lithography technology, a chemically amplified resist composition is known. The chemically amplified resist composition contains a polymer for a resist in which an acid-detachable group is detached by the action of an acid, and a photoacid generator. In recent years, pattern miniaturization has been progressing rapidly, and the development of a resist material that can further improve various lithography characteristics such as sensitivity, pattern formability, and line width roughness (LWR) is desired.

[0007] In the comparative example of Patent Document 2, a polymer obtained by polymerizing a mixture containing a monomer represented by formula (a1-1-2): a monomer represented by formula (a2-1-1): a monomer represented by formula (a3-1-1): a monomer represented by formula (I-2) in a molar ratio of 30:20:40:10 is described. Further, when a resist pattern was formed using a resist composition containing this polymer and a photoacid generator, it was shown that roughness occurred on the pattern side and the line width roughness (LWR) was inferior.

[0008]

Chemical formula

Prior art documents

Patent documents

[0009]

Patent Document 1

[0010] When producing a sulfonyl group-containing (meth)acrylate by a transesterification method as in Patent Document 1, in order to shift the equilibrium to the product side, an alcohol such as methanol generated by the reaction is removed by distillation. Therefore, it is necessary to raise the reaction temperature.

[0011] As a result of investigations by the present inventors, it has been clarified that a sulfonyl group-containing (meth)acrylate has high polymerizability, and when exposed to high temperatures in a transesterification reaction, a high molecular weight substance is generated by polymerization of the sulfonyl group-containing (meth)acrylate or the like. Patent Document 1 describes that the product is purified by recrystallization, washing, etc., but such a method cannot sufficiently remove the high molecular weight substance.

[0012] Further, in a resist composition containing a polymer having an acid-detachable group, improvement in LWR can be expected by improving the developability of the polymer.

[0013] An object of the present invention is to provide a polymer excellent in developability, to provide a resist composition containing the polymer, to provide a method for producing a substrate having a pattern formed using the resist composition, to provide a (meth)acrylate with reduced high molecular weight substance, or to provide a method for producing a (meth)acrylate with reduced high molecular weight substance. [Means for Solving the Problems]

[0014] 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), wherein the content of the structural unit based on a monomer having a polycyclic structure is 35 mol% or less.

[0015] [Chemical Formula]

[0016] In formula (1), R 1 represents a hydrogen atom or a methyl group; A 1 represents a linking group containing an ester bond or a single bond, provided that A 1 does not have a tertiary carbon atom; Z 1 represents an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to A 1 and -SO2-. [2] The polymer according to [1], further comprising a structural unit (2) having an acid-detachable group. [3] The polymer according to [2], wherein the structural unit (2) includes a structural unit (2i) having an acid-detachable group containing an alicyclic hydrocarbon group. [4] The polymer according to [3], wherein the structural unit (2) includes a structural unit (2ii) having an acid-detachable group containing a monocyclic alicyclic hydrocarbon group. [5] The polymer according to any one of [1] to [4], wherein the structural unit (1) is 15 mol% or more based on all the structural units. [6] The polymer according to any one of [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 [1] to [6] and a compound that generates an acid upon irradiation with actinic rays or radiation. [8] A method for manufacturing a substrate having a pattern, comprising the steps of: applying the resist composition according to [7] onto a surface of a substrate to be processed to form a resist film; exposing the resist film; and developing the exposed resist film with a developer.

[0017] [9] A method for producing a (meth)acrylate represented by the following formula (1x), having the following steps 1 and 2. Step 1: Obtaining a solution containing a (meth)acrylic acid ester (1x) represented by the following formula (1x) through a transesterification reaction between an alcohol represented by the following formula (2x) and a (meth)acrylic acid ester represented by the following formula (3x). Step 2: Adding a poor solvent to the solution containing the (meth)acrylic acid ester (1x) obtained in Step 1 to precipitate a high molecular weight substance and removing the high molecular weight substance.

[0018]

Chemical formula

[0019] In formula (1x), R 11 represents a hydrogen atom or a methyl group; A 11 represents a linking group containing an ester bond or a single bond, provided that A 11 does not have a tertiary carbon atom; Z 11 represents an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to A 11 and -SO2-. In formula (2x), Z 11 represents an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to the hydroxy group and -SO2-. In formula (3x), R 11 represents a hydrogen atom or a methyl group, and R 12 represents a linear or branched alkyl group having 1 to 10 carbon atoms.

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

[0020]

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

[0021]

Chemical formula

[0022] In formula (1x), R 11 represents a hydrogen atom or a methyl group; A 11 represents a linking group containing an ester bond or a single bond, provided that A 11 does not have a tertiary carbon atom; Z 11 is an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to A 11 and -SO2-.

Advantages of the Invention

[0023] According to the present invention, it is possible to provide a polymer having good developer solubility, a resist composition containing the polymer, and a method for producing a substrate having a pattern formed using the resist composition. According to the present invention, it is possible to provide a sulfonyl group-containing (meth)acrylate ester with reduced high molecular weight substances.

Modes for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail. The following definitions of terms apply throughout this specification and the claims. In this specification, “(meth)acrylic acid” means one or both of acrylic acid and methacrylic acid. In this specification, “constituent unit” means an atomic group formed by the polymerization reaction of a monomer. In this specification, the monomer represented by formula (1) may be referred to as monomer (1). The same applies to monomers represented by other formulas. In this specification, the compound represented by formula (1) may be referred to as compound (1). The same applies to compounds represented by other formulas.

[0025] <Polymer> The polymer of this embodiment (hereinafter also referred to as “polymer A”) contains a constituent unit (1) based on the monomer (1) represented by the following formula (1). With respect to all the constituent units of polymer A, the content of the constituent unit based on the monomer having a polycyclic structure is 35 mol% or less. The polymer A preferably further contains one or more structural units (2) having an acid-detachable group. The polymer A may contain one or more other structural units in addition to the structural units (1) and (2). The polymer A is suitable as a polymer for a resist.

[0026] [Structural unit (1)] The structural unit (1) is a structural unit formed by cleavage of the ethylenic double bond of the monomer (1).

[0027] [Chemical formula]

[0028] In formula (1), R 1 is a hydrogen atom or a methyl group. A 1 is a linking group containing an ester bond or a single bond. However, A 1 does not contain a tertiary carbon atom. Examples of the linking group include -A 2 -C(=O)O-, or -A 3 -O-C(=O)-. The A 2 , A 3 is a divalent chain hydrocarbon group having 1 to 5 carbon atoms. A 2 , A 3 The chain hydrocarbon group as may be linear or branched. A 2 , A 3 is preferably an alkylene group having 1 to 3 carbon atoms. A 2 , A 3 does not contain a tertiary carbon atom.

[0029] Z 1 is A 1It is an atomic group that forms a sulfur-containing cyclic hydrocarbon group (4-membered ring to 7-membered ring) having 3 to 6 carbon atoms including the carbon atom bonded to -SO2-. From the viewpoint of the stability of the cyclic structure, the sulfur-containing cyclic hydrocarbon group preferably has 4 to 6 carbon atoms. Further, a substituent may be bonded to the carbon atom constituting the sulfur-containing cyclic hydrocarbon group ring. Examples of the substituent include a linear or branched alkyl group having 1 to 10 carbon atoms, a hydroxy group, an amino group, an aldehyde group, a chloro group, a bromo group, and an iodo group.

[0030] For the monomer (1), it is preferable that no substituent is bonded to the carbon atom constituting the sulfur-containing cyclic hydrocarbon group ring, or an alkyl group having 1 to 6 carbon atoms is bonded as a substituent. The monomer in this embodiment is represented by the following formula (1’).

[0031]

Chemical formula

[0032] In formula (1’), R 1 , A 1 are the same as R 1 , A 1 in formula (1). n represents an integer of 1 to 4. The heterocyclic ring bonded to A 1 is, for example, a 4-membered ring when n is 1 and a 7-membered ring when n is 4. From the viewpoints of stability and ease of synthesis, n is preferably 2. R 2 represents a substituent bonded to the carbon atom constituting the heterocyclic ring. However, R 2 is not bonded to the carbon atom bonded to the above A 1 . m R 2 each 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 2 present in one molecule may be the same as 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.

[0033] Said A 1 Examples of the group bonded to include groups represented by the following formulas (1a) to (1d). In the formulas, * represents a bond to A 1 and represents a bond to A

[0034] [Chemical formula]

[0035] As the monomer (1), R 1 is a hydrogen atom or a methyl group, A 1 is a single bond, and a mode in which any of the groups represented by the formulas (1a) to (1d) is bonded to A 1 is preferable Among the groups represented by the formulas (1a) to (1d), the group represented by the formula (1b) is particularly preferable in terms of stability and ease of synthesis The constitutional unit (1) contained in the polymer A may be one kind or two or more kinds

[0036] With respect to all the constitutional units of the polymer A, the constitutional unit (1) is preferably 15 mol% or more, more preferably 20 mol% or more, and still more preferably 25 mol% or more. The upper limit is preferably 70 mol% or less, more preferably 60 mol% or less, and still more preferably 50 mol% or less from the viewpoints of sensitivity and resolution For example, with respect to all the constitutional units of the polymer A, the constitutional unit (1) is preferably 15 to 70 mol%, more preferably 20 to 60 mol%, still more preferably 25 to 60 mol%, and particularly preferably 25 to 50 mol%

[0037] [Constitutional unit (2)] The constitutional unit (2) is a constitutional unit based on a monomer having an acid-detachable group (hereinafter also referred to as monomer (2)). The acid-detachable group is a group having a bond that cleaves by the action of an acid, and a part or all of the acid-detachable group detaches from the polymer by the cleavage of the bond. In a positive chemically amplified resist composition, by heating after exposure, the acid-detachable group of the polymer reacts with an acid and detaches in the exposed portion, becoming soluble in an alkaline developer The monomer (2) is preferably a (meth)acrylic acid ester compound. As the (meth)acrylic acid ester compound having an acid-detachable group, known compounds can be used. The monomer (2) preferably contains a (meth)acrylic acid ester compound having an acid-detachable group containing an alicyclic hydrocarbon group in terms of dry etching resistance in the lithography process. The alicyclic hydrocarbon group may be monocyclic or polycyclic. The alicyclic hydrocarbon group may contain a heteroatom. The heteroatom is preferably one or more selected from the group consisting of O, S, and N. The number of atoms constituting the ring is preferably 5 to 22. Since it is excellent in the sensitivity and resolution of the resist, an acrylic acid ester having a tertiary carbon atom at the bonding site with the oxygen atom constituting the ester bond of the acrylic acid ester is more preferable. Specific examples include monomers (2-1) to (2-4) of the following formula. In particular, the monomer (2-4) is more preferable in that the effect of improving the developability solubility is easily obtained when combined with the constitutional unit (1).

[0038]

Chemical formula

[0039] In formulas (2-1) to (2-4), R 31 , R 32 , R 33 , R 34 each independently represents a hydrogen atom or a methyl group. R 21 , R 24 , R 25 each independently represents an alkyl group having 1 to 5 carbon atoms. The alkyl group may be linear or branched. R 22 , R 23 each independently represents an alkyl group having 1 to 3 carbon atoms. The alkyl group may be linear or branched. R 331 , R 332 , R 333 , R 334Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear or branched. X 1 、X 2 、X 3 、X 4 Each 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 from 0 to 4. When n1, n2, n3, or n4 is 2 or more, a plurality of Xs present in one molecule 1 、X 2 、X 3 or X 4 may be the same as or different from each other. Z 2 、Z 3 Each independently represents -O-, -S-, -NH-, or -(CH2)k-. k represents an integer from 1 to 6. q represents 0 or 1. r represents an integer from 0 to 3.

[0040] The structural unit (2) contained in polymer A may be one kind or two or more kinds. With respect to all the structural units of polymer A, the structural unit (2) is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%. When it is at least the lower limit value of the above range, good sensitivity is easily obtained, and when it is at most the upper limit value, a good balance as a resist is easily obtained, and good adhesion to the substrate is easily obtained.

[0041] The structural unit (2) preferably contains a structural unit (2i) having an acid-detachable 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 hetero atom is preferably one or more selected from the group consisting of O, S, and N. The number of atoms constituting the ring is preferably 5 to 22. With respect to the total number of moles of the constitutional unit (2), the content of the constitutional unit (2i) is preferably 25 mol% or more, more preferably 35 mol% or more, still more preferably 50 mol% or more, and particularly preferably 75 mol% or more. It may be 100 mol%. When the content of the constitutional unit (2i) is at least the above lower limit value, an effect of improving the developer solubility is easily obtained when combined with the constitutional unit (1).

[0042] The constitutional unit (2) more preferably contains a constitutional unit (2ii) having an acid-detachable group containing a monocyclic alicyclic hydrocarbon group. The monocyclic alicyclic hydrocarbon group preferably does not contain a heteroatom. The number of atoms constituting the ring of the monocyclic alicyclic hydrocarbon group is more preferably 5 to 8, and still more preferably 5 to 6. For example, the constitutional unit based on the monomer (2-4) is more preferable. With respect to the total number of moles of the constitutional unit (2), the content of the constitutional unit (2ii) is preferably 25 mol% or more, more preferably 35 mol% or more, still more preferably 50 mol% or more, and particularly preferably 75 mol% or more. It may be 100 mol%. When the content of the constitutional unit (2ii) is at least the above lower limit value, an effect of improving the developer solubility is easily obtained when combined with the constitutional unit (1).

[0043] With respect to all the constitutional units of the polymer A, the content of the constitutional unit based on the monomer having a polycyclic structure is 35 mol% or less, and more preferably 30 mol% or less. When the constitutional unit having a polycyclic structure is 35 mol% or less, the polymer A is excellent in developer solubility.

[0044] [Other constitutional units] As other constitutional units, constitutional units known in a chemically amplified resist composition can be used. For example, a constitutional unit having a lactone skeleton and a constitutional unit having a hydrophilic group can be mentioned.

[0045] (Constitutional unit having a lactone skeleton (hereinafter, also referred to as lactone unit).) The lactone skeleton means a monocyclic or polycyclic atomic group containing a ring having -O-C(=O)-. The ring having -O-C(=O)- may be a ring having -C(=O)-O-C(=O)-. The lactone skeleton preferably has a 4- to 20-membered ring, more preferably a 5- to 10-membered ring. The lactone skeleton may be a monocyclic ring of only a lactone ring, or an aromatic or non-aromatic hydrocarbon ring or heterocyclic ring may be condensed with the lactone ring.

[0046] As the monomer having a lactone skeleton, a (meth)acrylic acid ester compound is preferable. 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)acrylic acid ester having a substituted or unsubstituted δ-valerolactone ring and a (meth)acrylic acid ester having a substituted or unsubstituted γ-butyrolactone ring is preferable, and a monomer having an unsubstituted γ-butyrolactone ring is particularly preferable.

[0047] Specific examples of the monomer having a lactone skeleton include β-(meth)acryloyloxy-β-methyl-δ-valerolactone, 4,4-dimethyl-2-methylene-γ-butyrolactone, β-(meth)acryloyloxy-γ-butyrolactone, β-(meth)acryloyloxy-β-methyl-γ-butyrolactone, α-(meth)acryloyloxy-γ-butyrolactone, 2-(1-(meth)acryloyloxy)ethyl-4-butanolide, (meth)acrylic acid pantolactone, 5-(meth)acryloyloxy-2,6-norbornanecarbolactone, 8-methacryloxy-4-oxatricyclo[5.2.1.0 2,6 decane-3-one, 9-methacryloxy-4-oxatricyclo[5.2.1.0 2,6 decane-3-one, and the like. The lactone unit contained in Polymer A may be one kind or two or more kinds.

[0048] When Polymer A contains a lactone unit, its content is preferably 10 to 70 mol%, more preferably 20 to 60 mol%, and still more preferably 30 to 50 mol% based on all the constitutional units of Polymer A. When within the above range, the effect of improving the adhesion to the substrate is easily obtained.

[0049] (Constituent unit having a hydrophilic group (hereinafter also referred to as a hydrophilic unit)) The "hydrophilic group" in the present specification is one or more selected from the group consisting of -C(CF3)2-OH, hydroxy group, cyano group, methoxy group, carboxy group, and amino group. As the monomer having a hydrophilic group, a (meth)acrylic acid ester compound and a styrene derivative having a hydroxy group are preferable.

[0050] 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.

[0051] The constituent unit having a hydrophilic group contributes to improving the wettability of the polymer A to the developer. With respect to all the constituent units of the polymer A, the content of the constituent 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%. A good balance as a resist is easily obtained within the above range.

[0052] Preferable embodiments of the polymer A include the following embodiments (i) to (iv). (i) A polymer containing the constituent unit (1) and the constituent unit (2), wherein the constituent unit (1) is 15 to 70 mol% and the constituent unit (2) is 20 to 80 mol% with respect to all the constituent units, and the total of these is 35 to 100 mol%. (ii) A polymer comprising structural unit (1), structural unit (2), and a lactone unit, wherein, based on all the structural units, structural unit (1) is 15 to 70 mol%, the lactone unit is 10 to 70 mol%, the total of structural unit (1) and the lactone unit is 25 to 85 mol%, structural unit (2) is 20 to 80 mol%, and the total of structural unit (1), structural unit (2), and the lactone unit is 45 to 100 mol%. (iii) A polymer comprising structural unit (1), structural unit (2), and a hydrophilic unit, wherein, based on all the structural units, structural unit (1) is 15 to 70 mol%, the hydrophilic unit is 0 to 40 mol%, the total of structural unit (1) and the hydrophilic unit is 15 to 80 mol%, structural unit (2) is 20 to 80 mol%, and the total of structural unit (1), structural unit (2), and the hydrophilic unit is 35 to 100 mol%. (iv) A polymer comprising structural unit (1), structural unit (2), a lactone unit, and a hydrophilic unit, wherein, based on all the structural units, structural unit (1) is 15 to 70 mol%, the lactone unit is 10 to 70 mol%, the hydrophilic unit is 0 to 40 mol%, the total of structural unit (1), the lactone unit, and the hydrophilic unit is 25 to 85 mol%, structural unit (2) is 25 to 80 mol%, and the total of structural unit (1), structural unit (2), the lactone unit, and the hydrophilic unit is 50 to 100 mol%.

[0053] Polymer A can be produced, for example, by a solution polymerization method in which a monomer is radically polymerized using a polymerization initiator in the presence of a polymerization solvent. The weight average molecular weight of Polymer A is preferably from 1,000 to 100,000, more preferably from 3,000 to 50,000, and even more preferably from 5,000 to 30,000.

[0054] <Resist composition> The resist composition of this embodiment preferably contains Polymer A, a resist solvent, and a compound that generates an acid upon irradiation with actinic rays or radiation. Polymer A may be one kind or two or more kinds may be used in combination. The content of Polymer A in the resist composition (excluding the solvent) is not particularly limited, but is preferably 70 to 99.9% by mass.

[0055] Examples of the resist solvent include cyclopentanone, cyclohexanone, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), etc. The resist solvent may be used alone or in combination of two or more. The amount of the resist solvent used preferably ranges from 100 to 10,000 parts by mass with respect to 100 parts by mass of Polymer A, although it depends on the thickness of the resist film to be formed.

[0056] The compound that generates an acid upon irradiation with actinic rays or radiation can be arbitrarily selected from those that can be used as a photoacid generator in a chemically amplified resist composition. The photoacid generator may be used alone or in combination of two or more. Examples of the photoacid generator include onium salt compounds, sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds, quinonediazide compounds, diazomethane compounds, etc. The amount of the photoacid generator used is preferably from 0.1 to 20 parts by mass, more preferably from 0.5 to 10 parts by mass, with respect to 100 parts by mass of Polymer A.

[0057] The resist composition may contain various additives such as nitrogen-containing compounds, acid compounds (organic carboxylic acids, oxoacids of phosphorus or their derivatives), surfactants, other quenchers, sensitizers, antihalation agents, storage stabilizers, antifoaming agents, etc., if necessary. As the additives, those known in the field of resist compositions can be used.

[0058] <Method for manufacturing a substrate with a pattern formed thereon> An example of the method for manufacturing a substrate with a pattern formed thereon according to this embodiment will be described. First, a resist composition is applied onto the surface (the 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 a baking treatment (pre-bake) or the like to form a resist film on the substrate. Next, the resist film is irradiated with light having a wavelength of 250 nm or less through a photomask to form a latent image (exposure). As the irradiation light, a KrF excimer laser, an ArF excimer laser, an F2 excimer laser, or an EUV excimer laser is preferable, and an ArF excimer laser is particularly preferable. Further, an electron beam may be irradiated. Further, liquid immersion exposure may be performed in which light is irradiated in a state where a high refractive index liquid such as pure water, perfluoro-2-butyltetrahydrofuran, or perfluorotrialkylamine is interposed between the resist film and the final lens of the exposure apparatus.

[0059] After exposure, 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 a positive development process, the exposed portion is dissolved and removed with an alkaline developer. Polymer A has the bond of the acid-detachable group cleaved by the acid generated by exposure, and the dissolution rate of the exposed portion in the alkaline developer increases. As the alkaline developer, an alkaline aqueous solution is used. For example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; cyclic amines such as pyrrole and piperidine; and the like. After development, the substrate is appropriately rinsed with pure water or the like. In this way, a resist pattern is formed on the substrate to be processed. The substrate on which the resist pattern is formed is appropriately heat-treated (post-bake) to strengthen the resist, and the portion without the resist is selectively dry-etched. After dry etching, the resist is removed with a resist stripper to obtain a substrate on which a fine pattern is formed.

[0060] <(Meth)acrylate> The (meth)acrylate of this embodiment is a sulfonyl group-containing (meth)acrylate (Compound (1x)) represented by the following formula (1x), and is characterized in that the content of a high molecular weight polymer having a molecular weight of 5000 or more is 0.1% by mass or less.

[0061]

Chemical formula

[0062] In formula (1x), R 11 represents a hydrogen atom or a methyl group; A 11 represents a linking group containing an ester bond or a single bond, provided that A 11 does not have a tertiary carbon atom; Z 11 represents an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to A 11 and -SO2-.

[0063] Here, the (meth)acrylate of this embodiment in which the content of a high molecular weight polymer having a molecular weight of 5000 or more is defined may be referred to as a “(meth)acrylate composition” rather than a “(meth)acrylate”. However, in the (meth)acrylate of this embodiment, a high molecular weight polymer having a molecular weight of 5000 or more (hereinafter, may be simply referred to as a “high molecular weight polymer”) is contained in an extremely small amount of 0.1% by mass or less, or its content is below the detection limit and hardly contained. Further, since it is a “(meth)acrylate product” with a high molecular weight polymer content of 0.1% by mass or less and is further used for various applications, in this embodiment, the (meth)acrylate containing such an extremely small amount or hardly containing a high molecular weight polymer is referred to as a “(meth)acrylate”. Also, as described above, the high molecular weight polymer content of 0.1% by mass or less includes substantially 0% by mass of the high molecular weight polymer content, which is below the detection limit in the analysis of the high molecular weight polymer.

[0064] [Compound (1x)] In the formula (1x), A 11 is a linking group containing an ester bond or a single bond, provided that A 11 does not have a tertiary carbon atom. The linking group containing an ester bond as A 11 is the same as the linking group containing an ester bond as A 1 . From the viewpoints of raw material availability and ease of synthesis, A 11 is preferably a single bond. R 11 is a hydrogen atom or a methyl group, preferably a methyl group.

[0065] Z 11 is an atomic group that forms a sulfur-containing cyclic hydrocarbon group (4-membered ring to 7-membered ring) having 3 to 6 carbon atoms including the carbon atom bonded to A 11 and -SO2-. From the viewpoint of the stability of the cyclic structure, the sulfur-containing cyclic hydrocarbon group preferably has 4 to 6 carbon atoms. Further, a substituent may be bonded to the carbon atom constituting the sulfur-containing cyclic hydrocarbon group ring. Examples of the substituent include a linear or branched alkyl group having 1 to 10 carbon atoms, a hydroxy group, an amino group, an aldehyde group, a chloro group, a bromo group, and an iodo group.

[0066] From the viewpoints of raw material availability and compound stability, this sulfur-containing cyclic hydrocarbon group preferably has a 2-sulfolane or 3-sulfolane structure in which the ring containing a sulfonyl group is a 5-membered ring, and among them, the 3-sulfolane structure is most preferred. As the compound (1x), 3-sulfolanyl methacrylate is most preferred.

[0067] [High molecular weight substance] In this embodiment, the content of the high molecular weight substance in the (meth)acrylic acid ester can be analyzed by the method described in the Examples section below, and the detection limit thereof is 0.03% by mass or less.

[0068] The high molecular weight polymer in the (meth)acrylic acid ester of the present embodiment is a high molecular weight polymer formed by polymerization or copolymerization of the (meth)acrylic acid ester having a sulfonyl group, which is the target product (compound (1x)), or the compound (3x) described later, which is a raw material for producing the compound (1x), due to its high polymerizability in Step 1 of the method for producing the (meth)acrylic acid ester described later. Its molecular weight is 5000 or more, and the weight average molecular weight (Mw) measured by the method described in the Examples section below is 3×10 5 ~6×10 5 or so. If the high molecular weight polymer has a molecular weight of less than 5000, it is soluble in the solvent and thus remains in the mother liquor and is removed by recrystallization or the like, so it is not a target for removal in Step 2 described later.

[0069] The content of the high molecular weight polymer in the (meth)acrylic acid ester of the present embodiment is preferably as low as 0.1% by mass or less, preferably 0.05% by mass or less, more preferably 0.03% by mass or less, and most preferably below the detection limit.

[0070] The (meth)acrylic acid ester of the present embodiment with a reduced content of the high molecular weight polymer can be produced by the method for producing the (meth)acrylic acid ester of the present embodiment described later.

[0071] [Use] The (meth)acrylic acid ester of the present embodiment with a reduced content of the high molecular weight polymer can exhibit the excellent inherent properties of the sulfonyl group-containing (meth)acrylic acid ester without being affected by the high molecular weight polymer. For example, it is useful in a wide range of applications such as plastic raw materials, paints, adhesives, etc. In particular, the sulfonyl group-containing (meth)acrylic acid ester of the present embodiment is useful as a monomer constituting a polymer for resist applications, for example, for ArF resists. By using a monomer with a reduced content of the high molecular weight polymer, the lithography properties of the resist polymer can be improved. For example, the solubility and developability of the resist polymer can be improved, and defects during development derived from the high molecular weight polymer can be prevented. Also, the adhesion to the substrate and the affinity to polar solvents can be improved due to the sulfonyl group. The sulfonyl group-containing (meth)acrylate ester of the present embodiment can be preferably used as the monomer (1) constituting the polymer A.

[0072] <Method for Producing (Meth)Acrylate Ester> The method for producing a (meth)acrylate ester of the present embodiment is a method for producing a (meth)acrylate ester represented by the formula (1x), and includes the following steps 1 and 2.

[0073] Step 1: A step of obtaining a solution containing the (meth)acrylate ester represented by the formula (1x) by a transesterification reaction between an alcohol represented by the following formula (2x) and a (meth)acrylate ester represented by the following formula (3x).

[0074] [Chemical Formula]

[0075] In the formula (2x), Z 11 represents an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to the hydroxy group and -SO2-.

[0076] [Chemical Formula]

[0077] In the formula (3x), R 11 represents a hydrogen atom or a methyl group, and R 12 represents a linear or branched alkyl group having 1 to 10 carbon atoms.

[0078] Step 2: A step of adding a poor solvent to the solution containing the (meth)acrylate ester represented by the formula (1x) obtained in Step 1 to precipitate a high molecular weight substance and removing the high molecular weight substance.

[0079] [Step 1: Reaction Step] In Step 1, Compound (1x) is obtained by reacting the alcohol compound (2x) represented by the formula (2x) with the (meth)acrylic acid ester compound (3x) represented by the formula (3x).

[0080] In Compound (2x), Z 11 is an atomic group that forms a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms including the carbon atom bonded to the hydroxy group and -SO2-. From the viewpoint of the stability of the cyclic structure, the sulfur-containing cyclic hydrocarbon group preferably has 4 to 6 carbon atoms. Further, a substituent may be bonded to the 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 hydroxy group, an amino group, an aldehyde group, a chloro group, a bromo group, and an iodo group. From the viewpoint of easy availability of raw materials, the sulfur-containing cyclic hydrocarbon group preferably has a 2-sulfolane or 3-sulfolane structure in which the ring containing a sulfonyl group is a 5-membered ring. Among them, the 3-sulfolane structure is most preferable. As Compound (2x), 3-hydroxysulfolane is most preferable.

[0081] In Compound (3x), R 11 is a hydrogen atom or a methyl group, preferably a methyl group.

[0082] R 12 is a linear or branched alkyl group having 1 to 10 carbon atoms. Examples of the linear or branched alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, a t-butyl group, a normal pentyl group, a normal hexyl group, and a 2-ethylhexyl group. In the transesterification reaction, since it is necessary to remove the alcohol derived from the raw material ester by distillation, it is preferable that the boiling point of the by-product alcohol generated in the transesterification reaction is low. From this viewpoint, R 12 is preferably a methyl group. That is, as Compound (3x), methyl acrylate or methyl methacrylate is preferable.

[0083] In Project 1, compound (1x) is produced by a transesterification reaction. The conditions of the transesterification reaction are not particularly limited and may be carried out by known methods. For example, Japanese Patent Application Laid-Open No. 2007-153763 discloses a method of reacting 3-hydroxy sulfolane with methyl methacrylate to obtain 3-sulfolanyl methacrylate.

[0084] In order to obtain compound (1x) in good yield, it is preferable to use compound (2x) after dehydration. As a method of dehydration, a method of dissolving compound (2x) in an organic solvent and heating to remove water by azeotropy of the organic solvent and water is preferable. As the azeotropic organic solvent, benzene, toluene, ethylbenzene, methyl ethyl ketone, 1,4-dioxane, hexane, cyclohexane, etc. can be used. Also, when compound (3x) forms an azeotrope with water, compound (2x) can be dissolved in compound (3x) and dehydrated by azeotropy.

[0085] A catalyst may or may not be used in the transesterification reaction. In order to obtain compound (1x) in good yield, it is preferable to use a catalyst. When using a catalyst, a titanium catalyst or a tin catalyst can be used. Examples of the titanium catalyst include tetramethoxy titanium, tetraethoxy titanium, tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium, tetraisobutoxy titanium, etc. Examples of the tin catalyst include dinormal butyltin oxide, dinormal octyltin oxide, di-2-ethylhexyltin oxide, etc. From the viewpoint of the removability of the catalyst after the reaction, it is preferable to use a titanium catalyst.

[0086] The amount of the catalyst used is preferably 0.001 mol or more, more preferably 0.01 mol or more, per 1 mol of compound (2x) from the viewpoint of efficiently obtaining compound (1x). Also, the amount of the catalyst used is preferably 0.05 mol or less, more preferably 0.03 mol or less, per 1 mol of compound (2x) from the viewpoints of the removability of the catalyst and cost. The transesterification catalyst may be added at once or in portions. For example, the amount of the catalyst used is preferably 0.001 to 0.05 mol, more preferably 0.01 to 0.03 mol, per 1 mol of the compound (2x).

[0087] In the transesterification reaction, the amount of the compound (3x) used is not particularly limited. From the viewpoint of obtaining the compound (1x) in good yield, it is preferably 0.5 mol or more, more preferably 0.8 mol or more, and even more preferably 1.0 mol or more, per 1 mol of the compound (2x). In particular, when the by-produced alcohol is removed by azeotropy with the compound (3x), if the amount of the compound (3x) used is small, the by-produced alcohol cannot be sufficiently removed, and thus the reaction rate may decrease. Further, from the viewpoint of suppressing the kettle efficiency of the transesterification reaction and the load on the post-treatment process after the reaction, the amount of the compound (3x) used is preferably 12 mol or less, more preferably 10 mol or less, and even more preferably 8 mol or less, per 1 mol of the compound (2x). For example, the amount of the compound (3x) used is preferably 0.5 to 12 mol, more preferably 0.8 to 10 mol, and even more preferably 1 to 8 mol, per 1 mol of the compound (2x).

[0088] In order to suppress the polymerization of the compound (3x) and the compound (1x) in the reaction system, it is preferable to add a polymerization inhibitor. The type of the polymerization inhibitor is not particularly limited, and one type may be used or two or more types may be used.

[0089] Examples of the polymerization inhibitor include phenolic compounds such as hydroquinone, p-methoxyphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-tert-butyl-4-methylphenol, tert-butylcatechol, 2,6-di-tert-butyl-4-methylphenol; amine compounds such as N,N-diisopropyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N-di-2-naphthyl paraphenylenediamine; 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-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate.

[0090] In addition, in order to prevent polymerization, it is also preferable to bubble an oxygen-containing gas during the transesterification reaction. The amount of the oxygen-containing gas to be introduced can be set as appropriate. It is particularly preferable to use air as the oxygen-containing gas.

[0091] The temperature of the transesterification reaction is not particularly limited, but is preferably 30°C or higher, more preferably 60°C or higher, in order to remove the by-produced alcohol and improve the reaction rate. Also, in order to suppress the polymerization of compound (3x) and compound (1x), it is preferably 160°C or lower, more preferably 140°C or lower. For example, the temperature of the transesterification reaction is preferably 30 to 160°C, more preferably 60 to 140°C.

[0092] The time of the transesterification reaction is preferably 0.5 hours or longer, more preferably 1 hour or longer, from the viewpoint of efficiently obtaining compound (1x). Also, in order to suppress the polymerization of compound (3x) and compound (1x), it is preferably 50 hours or shorter, more preferably 30 hours or shorter. For example, the time of the transesterification reaction is preferably 0.5 to 50 hours, more preferably 1 to 30 hours.

[0093] As a post-treatment after the reaction, when using a catalyst, an operation to deactivate the catalyst may be performed. In particular, when the compound (1x) is used for a resist, it is preferable to reduce the mixing of metals as much as possible. Therefore, when a metal is used as the catalyst, it is preferable to deactivate and remove the catalyst. Examples of such methods include the following methods. That is, after cooling the reaction solution to approximately 70 °C or lower while stirring, water in an amount equal to or more than the added catalyst, an adsorbent, and celite as a filter aid are added to convert the catalyst into a metal oxide to deactivate it and precipitate it. Stirring is continued for about 1 to 5 hours after the addition is completed. The precipitated metal oxide can be removed by pressure filtration, vacuum filtration, or the like.

[0094] [Step 2: Purification Step] 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. Note that the precipitation of the high molecular weight substance by the poor solvent in this Step 2 is to precipitate the high molecular weight substance without precipitating the compound (1x), which is different from the washing operation and recrystallization operation described later in which the high molecular weight substance does not precipitate.

[0095] The poor solvent to be added is not particularly limited, and examples include hydrocarbon solvents such as pentane, hexane, heptane, cyclopentane, cyclohexane, octane, toluene, and xylene; ether solvents such as diethyl ether, diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, and dioxane; ester 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. It is more preferable to use a hydrocarbon solvent in which the solubility of the high molecular weight substance is low. Among them, saturated hydrocarbon solvents having 5 to 7 carbon atoms such as pentane, hexane, and heptane are even more preferable in terms of easy removal by distillation or the like.

[0096] The amount of the poor solvent can be appropriately determined according to the amount and solubility of the high molecular weight substance. In order to reduce the solubility of the high molecular weight substance and cause precipitation, it is preferably 0.2 times or more by mass, more preferably 0.5 times or more by mass, based on the mass of the compound (2x) used in the reaction. Also, for economic efficiency and kettle efficiency, it is preferably 5 times or less by mass, more preferably 3 times or less by mass, based on the mass of the compound (2x) used in the reaction. For example, the amount of the poor solvent is preferably 0.2 to 5 times by mass, more preferably 0.5 to 3 times by mass, based on the mass of the compound (2x) used in the reaction.

[0097] The method for removing the precipitated high molecular weight substance is not particularly limited, and examples include separation as a distillation residue, pressure filtration, vacuum filtration, centrifugation, etc. An appropriate method may be used as appropriate in consideration of the boiling point and properties of the compound (1x), the scale, the amount of the high molecular weight substance, etc. In order not to generate the high molecular weight substance again during the removal process, it is desirable to use pressure filtration, vacuum filtration, or centrifugation, which are methods that do not involve heating. After separation of the high molecular weight substance, it may be concentrated by vacuum distillation or the like to remove the poor solvent.

[0098] Step 2 may optionally include a purification operation of the compound (1x). Examples of the purification method of the compound (1x) include washing, heat treatment, filtration, distillation, recrystallization, etc. These may be carried out alone or in combination of two or more. The purification may be carried out before, after, or both before and after the precipitation step of the high molecular weight substance.

[0099] Since the compound (2x) has a sulfonyl group, it has high polarity and is easily soluble in water. Therefore, as a washing liquid, water or an aqueous solution in which 5 to 30% by mass of an inorganic salt such as sodium chloride, ammonium sulfate, or sodium sulfate is dissolved can be used for washing to remove the compound (2x) into the aqueous layer. The number of washing times can be appropriately determined. From the viewpoint of reducing the mixing of metals into the compound (1x), it is preferable to include a step of washing with water.

[0100] The washing may be carried out without adding a solvent, or may be diluted with a solvent. In order to reduce the hydrolysis of compound (1x) and its outflow into the aqueous layer, it is preferably diluted with a solvent. The solvent is not particularly limited, and hydrocarbon solvents such as pentane, hexane, heptane, cyclopentane, cyclohexane, octane, toluene, xylene, etc., ether solvents such as diethyl ether, diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, dioxane, etc., ester solvents such as ethyl acetate, butyl acetate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, etc. can be used. These solvents may be used alone or in combination of two or more. The amount of the solvent used can be appropriately determined according to the solubility of compound (1x) and the amount of the washing solution.

[0101] When purifying compound (1x) by distillation, it is preferable to add a polymerization inhibitor and carry out the distillation at a vacuum degree of 1.3 kPa (10 mmHg) or less while appropriately introducing an oxygen-containing gas such as air. In particular, in terms of having less thermal history, it is preferably carried out by a method such as thin film distillation.

[0102] When purifying the compound (1x) by recrystallization, a solvent is used that dissolves the compound (1x) between room temperature and 40°C and causes crystals to precipitate upon cooling to room temperature or below. Solvents used for recrystallization include alcohol solvents such as methanol, ethanol, isopropanol, and butanol; ester solvents such as ethyl acetate, butyl acetate, and methyl methacrylate; and ether solvents such as diethyl ether, diisopropyl ether, and t-butyl methyl ether, which can be used alone or in combination. In addition, in order to improve the recovery rate of recrystallization, hydrocarbon solvents such as hexane, octane, and heptane, which are difficult to dissolve crystals; halogen solvents such as chloroform, dichloroethane, and dichloromethane; water, etc. can also be mixed with the alcohol solvent, the ester solvent, or the ether solvent and used. From the viewpoint of easy reuse of the solvent, it is preferable to use an alcohol solvent alone. Also, a mixed solvent of an alcohol solvent and a hydrocarbon solvent is more preferable in terms of appropriately adjusting the slurry concentration when crystals precipitate and improving the recovery rate. The slurry concentration is preferably 25% by mass or less, more preferably 20% by mass or less, from the viewpoint of suppressing an increase in viscosity and improving processability. Also, from the viewpoints of economy and kettle efficiency, 5% by mass or more is preferable, and 10% by mass or more is more preferable. For example, the slurry concentration is preferably 5 to 25% by mass, more preferably 10 to 20% by mass.

[0103] In recrystallization, it is preferable to dissolve the compound (1x) in a solvent at 30°C or higher, gradually cool it, and add a seed crystal when the internal temperature reaches 5 to 10°C to promote crystallization. As crystallization occurs, the internal temperature rises due to the latent heat, but it is cooled so that when the internal temperature becomes 10°C or lower, the crystals are separated. The separation of the crystals can be carried out using a centrifugal filter, a pressure filter, etc. After separating the crystals, they are washed with a solvent. After recrystallization, it is preferable to separate the crystals using a solvent miscible or soluble in water, and then wash the wet crystal cake with water. This can remove most of the solvent adhering to the crystals, and there is almost no possibility of melting even if the temperature of the wet crystals rises near room temperature.

Example

[0104] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0105] ≪Example (I)≫ Reaction tracking was carried out by gas chromatography. <Method for Measuring Weight-Average Molecular Weight> The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer were determined in terms of polystyrene by gel permeation chromatography. Tetrahydrofuran (THF) was used as the eluent.

[0106] <Method for Measuring Copolymer Composition Ratio> For the polymers obtained in each example, the composition ratio of the constitutional units based on each monomer (unit: mol%) was 1 determined by 1H-NMR measurement. In this measurement, a JEOL Ltd. ECS-400 type superconducting FT (Fourier transform)-NMR apparatus was used. A sample solution of about 5 mass% (the solvent was deuterated chloroform) was placed in a sample tube with a diameter of 5 mmφ, and 64 integrations were performed at an observation frequency of 400 MHz in single pulse mode. The measurement temperature was 60°C.

[0107] <Evaluation Method for Developer Solubility (Turbidity Measurement Method)> Using a turbidimeter (manufactured by Orbeco-Hellige, product name: TB200), the turbidity Th(80) and turbidity Tm(80) were measured by the following measurement method. 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. The higher the turbidity, the lower the solubility in the organic solvent. In other words, the higher the turbidity, the higher the polarity and the better the solubility in the alkaline developer.

[0108] [Measurement Method for Turbidity Th(80)] (1) Dissolve the polymer to be measured in a mixed solvent of PGMEA / γ-butyrolactone = 75 / 25 mass% to prepare a PGMEA / γ-butyrolactone solution with a concentration of 20 mass% (hereinafter referred to as the sample solution). (2) Add n-heptane to the sample solution prepared in (1) to form a mixed solution, and determine the addition amount (Xh mass%) of n-heptane to the sample solution when the turbidity of the mixed solution reaches 10 NTU. (3) Add an amount of n-heptane corresponding to 80% of the Xh mass% to the sample solution prepared in (1), and stir at 25 °C for 4 hours to obtain a measurement solution. (4) Let the turbidity of the measurement solution at 25 °C be Th(80). [Method for measuring turbidity Tm(80)] (5) Add methanol to the sample solution prepared in (1) to form a mixed solution, and determine the addition amount (Xm mass%) of methanol to the sample solution when the turbidity of the mixed solution reaches 5.0 NTU. (6) Add an amount of methanol corresponding to 80% of the Xm mass% to the sample solution prepared in (1), and stir at 25 °C for 4 hours to obtain a measurement solution. (7) Let the turbidity of the measurement solution at 25 °C be Tm(80).

[0109] In the following Examples and Comparative Examples, the following monomers (m1) to (m7) were used.

[0110]

Chemical formula

[0111]

Chemical formula

[0112] [Example 1-1] Into a flask equipped with a nitrogen 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 a nitrogen atmosphere, and while stirring, the temperature of the water bath was raised to 80°C. Then, the following Mixture 1 was added dropwise into the flask from a dropping funnel over 4 hours, and the temperature of 80°C was maintained for 3 hours to obtain a reaction solution. (Composition of Mixture 1) 8.17 parts by mass (20 mol%) of monomer (m1), 10.20 parts by mass (30 mol%) of monomer (m2), 13.44 parts by mass (40 mol%) of monomer (m3), 4.72 parts by mass (10 mol%) of monomer (m4), Solvent: 8.9 parts by mass of PGMEA, 35.7 parts by mass of γ-butyrolactone, and Polymerization initiator: 3.91 parts by mass of dimethyl-2,2'-azobisisobutyrate (manufactured by Wako Pure Chemical Industries, Ltd., V601 (trade name)).

[0113] The obtained reaction solution was added dropwise with stirring to about 10 times the amount of a mixed solvent of methanol and water (methanol / water = 80 / 20 volume ratio) to obtain a precipitate of a white precipitate. The precipitate was filtered off, and again, it was put into the same amount of methanol as above, and the precipitate was washed while stirring. Then, the washed precipitate was filtered off to obtain a wet polymer powder. The wet polymer powder was dried at 60°C under reduced pressure for about 36 hours to obtain a dry powder polymer. The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the obtained polymer are shown in Table 1 (hereinafter the same). The turbidity of the obtained polymer was measured by the above method. The results are shown in Table 1 (hereinafter the same). Note that the copolymer composition ratio shown in Table 1 is the charging ratio. However, when the copolymer composition ratio of the obtained polymer was measured by the above method, the structural unit (m1) was 20.2 mol%, the structural unit (m2) was 30.1 mol%, the structural unit (m3) was 39.7 mol%, and the structural unit (m4) was 10.0 mol%, which was almost the same as the charging ratio.

[0114] 15.0 parts by mass of the dry powder polymer obtained above, 105.0 parts by mass of PGMEA, and 0.3 parts by mass of triphenylsulfonium triflate as a photoacid generator were mixed to form a homogeneous solution, and then filtered through a membrane filter with a pore size of 0.1 μm to produce a resist composition.

[0115] [Example 1-2, Comparative Example 1-1] The monomer charge composition in Example 1-1 was changed as shown in Table 1. Otherwise, the polymer was produced and evaluated in the same manner as in Example 1-1. Also, using the obtained polymer, a resist composition was produced in the same manner as in Example 1-1.

[0116] [Comparative Examples 2-1, 2-2] The monomer charge composition in Example 1-1 was changed as shown in Table 1. Otherwise, the polymer was produced and evaluated in the same manner as in Example 1-1. Also, using the obtained polymer, a resist composition was produced in the same manner as in Example 1-1.

[0117] [Examples 3-1, 4-1, Comparative Example 3-1] The monomer charge composition in Example 1-1 was changed as shown in Table 1. Otherwise, the polymer was produced and evaluated in the same manner as in Example 1-1. Also, using the obtained polymer, a resist composition was produced in the same manner as in Example 1-1.

[0118]

Table 1

[0119] As shown in Table 1, the polymers of Examples 1-1, 1-2, 3-1, and 4-1 have high polarity due to their high turbidity and excellent solubility in an alkali developer.

[0120] ≪Example (II)≫ In the following examples and comparative examples, 3-hydroxy sulfolane synthesized according to the method of Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-153763) was used. Methyl methacrylate was used, which was acrylate M (product name) manufactured by Mitsubishi Chemical Corporation. Tetrabutoxytitanium manufactured by Kanto Chemical Co., Inc. was used. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl manufactured by FUJIFILM Wako Pure Chemical Corporation was used. Celite 545 (product name) manufactured by Kishida Chemical Co., Ltd. was used as the celite.

[0121] The reaction rate in the transesterification reaction was calculated by the following formula from the peak areas measured by gas chromatography (hereinafter referred to as "GC"; apparatus: Agilent 6890GC manufactured by Agilent Technologies, column: HP-5). Reaction rate (%) = (A / B) × 100 Here, A represents the quantitative value of compound (1) according to the calibration curve, and B represents the total of the quantitative values of compound (1) and compound (2) according to the calibration curve.

[0122] The content of the high molecular weight substance was calculated as a quantitative value by the calibration curve from the peak area values measured by gel permeation chromatography (hereinafter referred to as "GPC"; apparatus: HLC-8320GPC manufactured by Tosoh Corporation, column: Shodex LF-804 (3 pieces), eluent: tetrahydrofuran).

[0123] The weight average molecular weight (Mw) of the high molecular weight substance was calculated using a calibration curve with standard polystyrene from the elution time measured by GPC (apparatus: HLC-8320GPC manufactured by Tosoh Corporation, column: Shodex LF-804 (3 pieces), eluent: tetrahydrofuran).

[0124] <Example 5-1> [Step 1] To a 100 mL glass flask equipped with a Dean-Stark apparatus, add 20.1 g (147 mmol) of 3-hydroxythiolane, 103.1 g (1.0 mol) of methyl methacrylate, and 0.12 g of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter referred to as "HO-TEMPO"), and heat under reflux to remove the moisture in the solution by means of the Dean-Stark apparatus. Next, add 1.5 g (4 mmol) of tetrabutoxytitanium, and while blowing air at 20 mL / min, heat the reaction solution and reflux it at an internal temperature of 100 to 110 °C. While removing the methanol generated by the reaction by azeotropy with methyl methacrylate using the Dean-Stark apparatus, stir for 2.5 hours. The mixed solution of methanol and methyl methacrylate withdrawn during this period was 45.8 g. The reaction rate by GC analysis was 91%. Then, after cooling to room temperature, add 1.6 g of water and 6.9 g of celite and stir for 1 hour, and filter the obtained mixed solution under reduced pressure using filter paper. When GPC analysis and Mw measurement were performed, a high molecular weight polymer with Mw 4.6×10 5 was detected at 1.15 mass%.

[0125] [Step 2] Add 30 mL of toluene to the obtained filtrate, add 15 mL of water to wash the organic layer, and discharge the aqueous layer using a separatory funnel. Then add 20 mL of water to wash the organic layer and discharge the aqueous layer using a separatory funnel. Next, add 24 g of hexane and stir to precipitate a gel-like high molecular weight polymer. After adding magnesium sulfate and drying, filter under reduced pressure using filter paper, concentrate the filtrate using an evaporator, and obtain 22.1 g of crude 3-sulfanylmethyl acrylate. As a result of GPC analysis, no high molecular weight polymer with a molecular weight of 5000 or more was detected. Add 66.2 g of 2-propanol and 33.1 g of heptane to the obtained crude 3-sulfanylmethyl acrylate, cool with stirring, and when the temperature drops below 20 °C, add seed crystals to precipitate crystals. Filter the obtained crystals, wash the crystals with heptane and water, and dry under reduced pressure to obtain 12.9 g of purified 3-sulfanylmethyl acrylate. As a result of GPC analysis, no high molecular weight polymer with a molecular weight of 5000 or more was detected.

[0126] [Example 5-2] [Project 1] Into a 3 L glass flask equipped with a stirrer, thermometer, and Dean-Stark apparatus, 351 g (2.6 mol) of 3-hydroxy sultone, 1770 g (17.7 mol) of methyl methacrylate, and 2.2 g of HO-TEMPO were added, and the mixture was heated to reflux to remove the water in the solution by Dean-Stark. Next, 26 g (77 mmol) of tetrabutoxytitanium was added, and while blowing air at 20 mL / min, the reaction solution was heated and refluxed at an internal temperature of 100 to 110 °C. Methanol produced by the reaction was removed using Dean-Stark by azeotropy with methyl methacrylate, and the mixture was stirred for 8 hours. The mixed solution of methanol and methyl methacrylate withdrawn during this period was 902 g. The reaction rate by GC analysis was 88%. After cooling to room temperature, 28 g of water and 121 g of celite were added and stirred for 1 hour, and the resulting mixed solution was filtered under reduced pressure through filter paper. When GPC analysis and Mw measurement were performed, a high molecular weight polymer with Mw 4.0×10 5 was detected at 0.08 mass%.

[0127] [Project 2] 900 mL of toluene was added to the obtained filtrate, 200 mL of water was added to wash the organic layer, and 242 g of the aqueous layer was separated. Next, 200 mL of water was added to wash the organic layer, and 204 g of the aqueous layer was separated. Next, 650 mL of hexane was added and stirred to precipitate a gel-like high molecular weight polymer. After adding magnesium sulfate and drying, it was filtered under reduced pressure using filter paper, and the filtrate was concentrated using an evaporator to obtain 406 g of crude 3-sulfonylmethyl acrylate. As a result of GPC analysis, no high molecular weight polymer with a molecular weight of 5000 or more was detected. While maintaining the obtained crude 3-sulfonylmethyl acrylate at 26 °C, 1181 g of 2-propanol and 592 g of heptane were added and cooled with stirring. When the temperature dropped below 20 °C, seed crystals were added to precipitate crystals. The obtained crystals were filtered, washed with heptane and water, and dried under reduced pressure to obtain 219 g of purified 3-sulfonylmethyl acrylate. As a result of GPC analysis, no high molecular weight polymer with a molecular weight of 5000 or more was detected.

[0128] [Example 5-3] [Project 1] In a 10 L glass separable flask equipped with a stirrer, a thermometer, and a Dean-Stark apparatus, 1394 g (10.2 mol) of 3-hydroxy sulfolane, 7269 g (72.6 mol) of methyl methacrylate, and 4.4 g of HO-TEMPO were added, and the mixture was heated to reflux to remove the moisture in the solution by means of the Dean-Stark apparatus. Next, 70 g (0.2 mol) of tetrabutoxytitanium was added, and while blowing air at 20 mL / min, the reaction solution was heated and refluxed at an internal temperature of 100 - 110 °C. While removing the methanol generated by the reaction by azeotropy with methyl methacrylate using the Dean-Stark apparatus, the mixture was stirred for 6 hours. The mixed solution of methanol and methyl methacrylate withdrawn during this period was 1477 g. The reaction rate by GC analysis was 67%. Then, it was cooled to 70 °C or lower, 35 g (0.1 mol) of tetrabutoxytitanium was added, and while blowing air at 20 mL / min, the reaction solution was heated and refluxed at an internal temperature of 100 - 110 °C. While removing the methanol generated by the reaction by azeotropy with methyl methacrylate using the Dean-Stark apparatus, the mixture was stirred for 7.5 hours. The mixed solution of methanol and methyl methacrylate withdrawn during this period was 2081 g. The reaction rate by GC analysis was 87%. It was cooled to 70 °C or lower again, 3.5 g (0.01 mol) of tetrabutoxytitanium was added, and while blowing air at 20 mL / min, the reaction solution was heated and refluxed at an internal temperature of 100 - 110 °C. It was stirred for 3.5 hours, but the reaction rate by GC analysis was 87%. The mixed solution of methanol and methyl methacrylate withdrawn during this period was 525 g. Thereafter, after cooling to 70 °C or lower, 16 g of water and 483 g of celite were added and stirred for 1 hour, and the resulting mixed solution was pressure-filtered through filter paper. When GPC analysis and Mw measurement were carried out, a high molecular weight polymer with Mw 4.2×10 5 was detected at 0.21 mass%.

[0129] [Project 2] 3000 g of toluene was added to the obtained filtrate, 812 g of water was added to wash the organic layer, and 965 g of the aqueous layer was separated. Next, 837 g of water was added to wash the organic layer, and 852 g of the aqueous layer was separated. Next, 2020 g of hexane was added and stirred to precipitate a gel-like high molecular weight substance. The high molecular weight substance was removed by pressure filtration through filter paper, and the filtrate was concentrated using an evaporator to obtain 1641 g of crude 3-sulforanilyl methacrylate. As a result of GPC analysis, no high molecular weight substance with a molecular weight of 5000 or more was detected. While maintaining the obtained crude 3-sulforanilyl methacrylate at 22°C, 4690 g of 2-propanol and 2380 g of heptane were added and cooled with stirring. When the temperature dropped below 17°C, seed crystals were added to precipitate crystals. The obtained crystals were filtered, washed with heptane and water, and dried under reduced pressure to obtain 1000 g of purified 3-sulforanilyl methacrylate. As a result of GPC analysis, no high molecular weight substance with a molecular weight of 5000 or more was detected.

[0130] <Comparative Example 5-1> Using 20.0 g (147 mmol) of 3-hydroxy sulfolane, 118.0 g (1.2 mol) of methyl methacrylate, 0.12 g of HO-TEMPO, and 0.7 g (4 mmol) of tetraethoxytitanium, Step 1 was carried out in the same manner as in Example 5-1. When GPC analysis and Mw measurement of the filtrate were performed, a high molecular weight substance with Mw 4.8×10 5 was detected at 0.29 mass%.

[0131] 30 mL of toluene was added to the obtained filtrate, 15 mL of water was added, the organic layer was washed, and the aqueous layer was drained using a separatory funnel. Thereafter, 15 mL of water was added, the organic layer was washed, and the aqueous layer was drained using a separatory funnel. After adding magnesium sulfate for drying, filtration was performed under reduced pressure using filter paper, the filtrate was concentrated using an evaporator, and 25.6 g of crude 3-sulfonylmethyl methacrylate was obtained. As a result of GPC analysis, 0.22 mass% of a high molecular weight substance was detected. When 38.9 g of 2-propanol was added to this crude 3-sulfonylmethyl methacrylate, a gel-like high molecular weight substance precipitated. However, 38.4 g of 2-propanol and 38.5 g of heptane were further added as it was, and when the temperature dropped below 20 °C, a seed crystal was added and recrystallization was carried out to obtain 21.3 g of purified 3-sulfonylmethyl methacrylate. As a result of analysis by GPC, 0.11 mass% of a high molecular weight substance having a molecular weight of 5000 or more was detected.

[0132] In these examples, the results of Mw measurement and GPC analysis of the high molecular weight substance in each step are shown in Table 2 below. In Table 2, after step 1 means after the reaction is completed, after step 2 means after adding a poor solvent to precipitate and remove the high molecular weight substance and concentrating, and after recrystallization represents the analysis results of the purified 3-sulfonylmethyl methacrylate obtained by recrystallization purification. N.D. indicates that it was not detected.

[0133]

Table 2

[0134] As shown in the results of Table 2, the 3-sulfonylmethyl methacrylate obtained in Examples 5-1 to 5-3 was of high purity in which no high molecular weight substance having a molecular weight of 5000 or more was detected. On the other hand, in Comparative Example 5-1 in which step 2 was not performed, the obtained 3-sulfonylmethyl methacrylate contained 0.11 mass% of a high molecular weight substance having a molecular weight of 5000 or more. From these results, it can be seen that by precipitating the high molecular weight polymer with a poor solvent in the purification process, the high molecular weight polymer can be removed, and the content of the high molecular weight polymer having a molecular weight of 5000 or more can be reduced to 0.1% by weight or less.

Industrial Applicability

[0135] According to the present embodiment, a polymer having good developer solubility, a resist composition containing the polymer, and a method for producing a substrate on which a pattern using the resist composition is formed can be obtained. According to the present embodiment, a sulfonyl group-containing (meth)acrylate ester with a reduced high molecular weight polymer can be obtained. The (meth)acrylate ester of the present embodiment has a reduced high molecular weight polymer content and is useful for a wide variety of applications such as plastics, paints, and adhesives. It is also suitable as a monomer constituting a polymer for resists and is useful for improving lithography characteristics.

Claims

1. A polymer comprising a constitutional unit (1) based on a monomer represented by the following formula (1) and a constitutional unit (2) having an acid-detachable group, wherein the constitutional unit (2) includes a constitutional unit (2i) having an acid-detachable group containing an alicyclic hydrocarbon group, the constitutional unit (2) includes a constitutional unit (2ii) having an acid-detachable group containing a monocyclic alicyclic hydrocarbon group, and the content of the constitutional unit based on a monomer having a polycyclic structure is 35 mol% or less, and the constitutional unit (1) is 15 mol% or more based on all the constitutional units. 【Chemical 1】 In formula (1), R １ represents a hydrogen atom or a methyl group; A １ represents a linking group containing an ester bond or a single bond, provided that A １ does not have a tertiary carbon atom; Z １ represents an atomic group that, together with the carbon atom bonded to A １ and including -SO ２ -, forms a sulfur-containing cyclic hydrocarbon group having 4 carbon atoms.

2. The polymer according to claim 1, further comprising a constitutional unit (3) having a lactone skeleton.

3. A resist composition comprising the polymer according to claim 1 or 2 and a compound that generates an acid upon irradiation with actinic rays or radiation.

4. A method for manufacturing a substrate having a pattern, comprising the steps of: applying the resist composition according to claim 3 onto a surface of a substrate to be processed to form a resist film; exposing the resist film; and developing the exposed resist film using a developer.

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