阅读说明：本技术 单体、光致抗蚀剂用树脂、光致抗蚀剂用树脂组合物以及图案形成方法 (Monomer, resin for photoresist, resin composition for photoresist, and pattern formation method ) 是由 江口明良 上原和浩 丸山孝 于 2019-09-12 设计创作，主要内容包括：本发明的目的在于提供在形成耐溶胀性优异的光致抗蚀剂用树脂时有用的单体。本发明的光致抗蚀剂用树脂包含下述式(Y)所示的聚合单元,<Image he="489" wi="700" file="DDA0002200253380000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(式(Y)中,R<Sup>X</Sup>表示卤原子或被卤原子取代的碳原子数为1～6的烷基,A<Sup>1</Sup>表示单键或连接基团,当A<Sup>1</Sup>表示连接基团时,A<Sup>1</Sup>和R<Sup>X1</Sup>任选相互键合而形成环,R<Sup>X1</Sup>表示氢原子、碳原子数为1～6的烷基、或碳原子数为2～6的烯基,n表示0～5的整数,当n为2以上时,R<Sup>X1</Sup>任选相同或不同,任选相互键合而形成环,m表示1～4的整数)。(The purpose of the present invention is to provide a monomer useful for forming a resin for a photoresist having excellent swelling resistance. The resin for a photoresist of the present invention comprises a polymerized unit represented by the following formula (Y), (in the formula (Y), R X Represents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A 1 Represents a single bond or a linking group, when A 1 When represents a linking group, A 1 And R X1 Optionally bonded to each other to form a ring, R X1 Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is X1 Optionally the same or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4).)

1. A resin for a photoresist, which comprises a polymerized unit represented by the following formula (Y),

in the formula (Y), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A¹Represents a single bond or a linking group, when A¹When represents a linking group, A¹And R^X1Optionally bonded to each other to form a ring, R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X1Optionally identical or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4.

2. The resin for a photoresist according to claim 1, comprising at least one polymerization unit selected from a polymerization unit represented by the following formula (Y1) and a polymerization unit represented by the following formula (Y2),

in the formula (Y1), R^XRepresents a halogen atom or a carbon atom substituted by a halogen atom having 1Alkyl of about 6, R^X2Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X2Optionally identical or different, optionally bonded to each other to form a ring,

in the formula (Y2), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X3And R^X4The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R^X3And R^X4Optionally bonded to each other to form a ring.

3. The resin for a photoresist according to claim 1 or 2, further comprising at least one polymerized unit selected from polymerized units represented by the following formulae (a1) to (a4),

in the formulae (a1) to (a4), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom, A represents a single bond or a linking group, R represents a hydrogen atom, a halogen²～R⁴The same or different, represents an optionally substituted alkyl group having 1 to 6 carbon atoms, and R²And R³Optionally bonded to each other to form a ring, R⁵、R⁶The same or different, represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, R⁷represents-COOR^cGroup R is^cRepresents an optionally substituted tertiary hydrocarbon group, tetrahydrofuryl, tetrahydropyranyl or oxepanyl group, n represents an integer of 1 to 3, R represents^aIs bonded to ring Z¹The substituents of (A) are the same or different and represent oxo, alkyl, hydroxy optionally protected by a protecting group, hydroxyalkyl optionally protected by a protecting group, or carboxy optionally protected by a protecting group, p represents 0An integer of about 3, ring Z¹Represents an alicyclic hydrocarbon ring having 3 to 20 carbon atoms.

4. The resin for a photoresist according to any one of claims 1 to 3, further comprising at least one polymerized unit selected from polymerized units represented by the following formulas (b1) to (b5) except polymerized units belonging to the polymerized unit represented by the formula (Y),

in the formulae (b1) to (b5), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom, A represents a single bond or a linking group, X represents an unbonded group, a methylene group, an ethylene group, an oxygen atom, or a sulfur atom, Y represents a methylene group or a carbonyl group, Z represents a divalent organic group, and V represents¹～V³Same or different and represents-CH₂-、[-C(＝O)-]Or [ -C (═ O) -O-]Wherein V is¹～V³Is [ -C (═ O) -O-]，R⁸～R¹⁴The same or different, represents a hydrogen atom, a fluorine atom, an alkyl group optionally having a fluorine atom, a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group.

5. The resin for photoresist according to any one of claims 1 to 4, further comprising a polymerized unit represented by the following formula (c1),

in the formula (c1), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom, A represents a single bond or a linking group, R^bRepresents a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group, q represents an integer of 1 to 5, and the ring Z²Represents an alicyclic hydrocarbon ring having 6 to 20 carbon atoms.

6. A resin composition for a photoresist, comprising at least:

the resin for photoresist according to any one of claims 1 to 5, and

a radiation-sensitive acid generator.

7. A pattern forming method at least includes the following steps:

a coating film formed by applying the resin composition for a photoresist according to claim 6 to a substrate, exposing the coating film to light, and then dissolving the coating film with an alkali.

8. A monomer represented by the following formula (X),

in the formula (X), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A¹Represents a single bond or a linking group, when A¹When represents a linking group, A¹And R^X1Optionally bonded to each other to form a ring, R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X1Optionally identical or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4.

9. The monomer according to claim 8, which is a monomer represented by the following formula (X1) or a monomer represented by the following formula (X2),

in the formula (X1), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X2Represents a hydrogen atom, has 1 to c carbon atoms6 alkyl or alkenyl having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R^X2Optionally identical or different, optionally bonded to each other to form a ring,

in the formula (X2), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X3And R^X4The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R^X3And R^X4Optionally bonded to each other to form a ring.

Technical Field

The invention relates to a monomer, a resin composition, and a pattern forming method.

Background

In the manufacture of semiconductors, a photolithography technique for patterning is a remarkable innovation. First, i-ray and g-ray are used for exposure in photolithography, and the line width of a pattern is also wide, so that the capacity of a manufactured semiconductor is low. However, due to recent technological development, use of KrF excimer lasers with shorter wavelengths and ArF excimer lasers with shorter wavelengths has become possible, and the line widths thereof have also become dramatically finer.

In exposure with a KrF excimer laser, a novolak-type or styrene-type resin is used, but since the resin contains an aromatic group, there is a problem that a laser beam by an ArF excimer laser is absorbed. Therefore, in the exposure with the ArF excimer laser, a resin containing no aromatic group (for example, a resin having an alicyclic skeleton) has been used instead of the resin containing an aromatic group. The resin used in the exposure with the ArF excimer laser is mainly an acrylic resin. This applies the following mechanism: in the case of using a resin composition containing a radiation-sensitive acid generator and an acrylic resin containing (meth) acrylic acid protected with a protecting group as a monomer unit, the protecting group of the monomer unit is released by an acid generated by exposure to become a carboxyl group, and becomes alkali-soluble.

Many of the conventionally used protective groups are groups containing an alicyclic skeleton having no polarity, but they have poor adhesion to substrates and lack affinity for alkali developer, and therefore, many acrylic monomers containing an alicyclic skeleton having polarity (for example, a skeleton having an ester group) have been proposed. Among them, alicyclic skeletons having a lactone ring have been highly evaluated for their functionality and are widely used (patent documents 1 and 2).

In addition, with the progress of miniaturization, the demand for improving line width variation of a formed pattern called line width roughness (hereinafter referred to as "LWR") is further increasing. As one of the causes of LWR deterioration, swelling of a pattern by an alkali developing solution is given, and as a method for solving this problem, a method using a resin containing a specific tertiary ester unit having a cyclic ether structure has been proposed (patent document 3).

Disclosure of Invention

Problems to be solved by the invention

However, the resin is insufficient in swelling resistance (property of suppressing swelling of a pattern by an alkali developing solution), and therefore further improvement is required.

Accordingly, an object of the present invention is to provide a monomer useful for forming a resin having excellent swelling resistance. Another object of the present invention is to provide a resin having excellent swelling resistance, and a resin composition containing the resin. Another object of the present invention is to provide a method for forming a fine pattern having excellent swelling resistance with high accuracy by using the resin composition.

Means for solving the problems

The present inventors have conducted extensive studies to achieve the above object, and as a result, have found that swelling resistance can be improved by using a resin containing a polymer unit having a specific structure. The present invention has been completed based on these findings.

That is, the present invention provides a resin for a photoresist, which contains a polymerization unit represented by the following formula (Y).

[ chemical formula 1]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A¹Represents a single bond or a linking group, when A¹When represents a linking group，A¹And R^X1Optionally bonded to each other to form a ring, R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X1Optionally identical or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4. )

The resin preferably contains at least one polymerization unit selected from the group consisting of a polymerization unit represented by the following formula (Y1) and a polymerization unit represented by the following formula (Y2).

[ chemical formula 2]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X2Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X2Optionally identical or different, optionally bonded to each other to form a ring. )

[ chemical formula 3]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X3And R^X4The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R^X3And R^X4Optionally bonded to each other to form a ring. )

The resin preferably further contains at least one polymerization unit selected from the polymerization units represented by the following formulae (a1) to (a4),

[ chemical formula 4]

(wherein R represents a hydrogen atom, a halogen atom, or a carbon atom having an optional halogen atomIs an alkyl group of 1 to 6, A represents a single bond or a linking group, R²～R⁴The same or different alkyl groups each having 1 to 6 carbon atoms and optionally having a substituent. Wherein R is²And R³Optionally bonded to each other to form a ring, R⁵、R⁶The same or different, represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, R⁷represents-COOR^cGroup R is^cRepresents an optionally substituted tertiary hydrocarbon group, tetrahydrofuryl, tetrahydropyranyl or oxepanyl group, n represents an integer of 1 to 3, R represents^aIs bonded to ring Z¹The substituents (A) are the same or different and represent an oxo group, an alkyl group, a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, or a carboxyl group optionally protected by a protecting group, p represents an integer of 0to 3, and the ring Z¹Represents an alicyclic hydrocarbon ring having 3 to 20 carbon atoms. )

The resin preferably contains at least one polymerization unit selected from the polymerization units represented by the following formulae (b1) to (b5) (except those belonging to the polymerization unit represented by the formula (Y)).

[ chemical formula 5]

(wherein R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom, A represents a single bond or a linking group, X represents an unbonded group, a methylene group, an ethylene group, an oxygen atom, or a sulfur atom, Y represents a methylene group or a carbonyl group, Z represents a divalent organic group, and V represents¹～V³Same or different and represents-CH₂-、[-C(＝O)-]Or [ -C (═ O) -O-]. Wherein, V¹～V³Is [ -C (═ O) -O-]，R⁸～R¹⁴The same or different, represents a hydrogen atom, a fluorine atom, an alkyl group optionally having a fluorine atom, a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group. )

The resin preferably contains a polymerization unit represented by the following formula (c1),

[ chemical formula 6]

(wherein R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom, A represents a single bond or a linking group, and R represents a hydrogen atom, a halogen atom, or a halogen atom-containing alkyl group^bRepresents a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group, q represents an integer of 1 to 5, and the ring Z²Represents an alicyclic hydrocarbon ring having 6 to 20 carbon atoms. )

Further, the present invention provides a resin composition containing at least the resin and a radiation-sensitive acid generator.

Further, the present invention provides a pattern forming method including at least the steps of: the composition is applied to a substrate to form a coating film, the coating film is exposed to light, and then alkali dissolution is performed.

Further, the present invention provides a monomer represented by the following formula (X),

[ chemical formula 7]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A¹Represents a single bond or a linking group, when A¹When represents a linking group, A¹And R^X1Optionally bonded to each other to form a ring, R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X1Optionally identical or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4. )

The monomer is preferably a monomer represented by the following formula (X1) or a monomer represented by the following formula (X2).

[ chemical formula 8]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X2Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X2Optionally identical or different, optionally bonded to each other to form a ring. )

[ chemical formula 9]

(in the formula, R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, R^X3And R^X4The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, R^X3And R^X4Optionally bonded to each other to form a ring. )

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a monomer useful for forming a resin having excellent swelling resistance can be provided. Further, a resin excellent in swelling resistance and a resin composition containing the resin can be provided. Further, a method for forming a fine pattern having excellent swelling resistance with high accuracy by using the resin composition can be provided.

Detailed Description

< monomer >

The monomer of the present invention is represented by the following formula (X).

[ chemical formula 10]

In the formula (X), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, A¹Represents a single bond or a linking group, when A¹When represents a linking group, A¹And R^X1Optionally bonded to each other to form a ring, R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, n represents an integer of 0to 5, and when n is 2 or more, R is^X1Optionally identical or different, optionally bonded to each other to form a ring, and m represents an integer of 1 to 4.

R^XThe halogen atom in (b) is not particularly limited, but from the viewpoint of improving the swelling resistance, a fluorine atom or a chlorine atom is preferable, and a fluorine atom is more preferable. Furthermore, R^XThe number of carbon atoms of the alkyl group in (1) is not particularly limited, and is 1 to 6, preferably 1 to 3, and more preferably 1 or 2. I.e. as R^XThe alkyl group having 1 to 6 carbon atoms substituted with a halogen atom in (2) is preferably an alkyl group having 1 or 2 carbon atoms substituted with a fluorine atom such as a fluoromethyl group, difluoromethyl group, trifluoromethyl group, 2,2, 2-trifluoroethyl group, 1,2,2, 2-pentafluoroethyl group and the like, and more preferably a trifluoromethyl group, from the viewpoint of improving the swelling resistance.

The reason why the swelling resistance is improved in the monomer represented by the formula (X) is not clear, but it is considered that R is used^XThe resin, which is a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom and contains a polymerization unit derived from the monomer (i.e., a polymerization unit represented by formula (Y)), has improved water repellency, and as a result, the resin film is less likely to be impregnated with an alkali developing solution, and swelling of the pattern is suppressed.

R^X1The alkyl group in (1) is not particularly limited as long as it has 1 to 6 carbon atoms, and is preferably 1 to 4, for example. R^X1The number of carbon atoms of the alkenyl group in (1) is not particularly limited, and is preferably 2 to 6, for example. When n is more than 2, R^X1When they are bonded to each other to form a ring, R^X1The ring may be formed via an oxygen atom or a sulfur atom. Further, the carbon constituting the ring may form a double bond with an adjacent carbon atom. The number of carbon atoms constituting the ring is not particularly limited, and is, for example, preferably 4 to 12, more preferably 4 to 10, and still more preferably 4 to 6.

As A¹Examples of the linking group in (1) include: alkylene groups, carbonyl groups (-C ═ O) -), ether bonds (-O-), ester bonds (-C (═ O)-O-), amide bonds (-C (═ O) -NH-), carbonate bonds (-O-C (═ O) -O-), and groups in which a plurality of these are linked. Examples of the alkylene group include: divalent alicyclic hydrocarbon groups (particularly divalent cycloalkylene groups) such as a linear or branched alkylene group (e.g., a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, or a trimethylene group), 1, 2-cyclopentylene group, 1, 3-cyclopentylene group, cyclopentylidene group, 1, 2-cyclohexylene group, 1, 3-cyclohexylene group, 1, 4-cyclohexylene group, or cyclohexylidene group. In A¹When the lactone ring is bonded to the α th position of the lactone ring, the substrate adhesion of the resin tends to be improved.

When A is¹And R^X1When they are bonded to each other to form a ring, the ring may be formed via an oxygen atom or a sulfur atom. Further, the carbon constituting the ring may form a double bond with an adjacent carbon atom. The number of carbon atoms constituting the ring is not particularly limited, but is preferably 4 to 12, more preferably 4 to 10, and still more preferably 4 to 6.

The monomer of the present invention is not particularly limited, and examples thereof include monomers represented by the following formulae (X1) and (X2).

[ chemical formula 11]

[ chemical formula 12]

In the formula (X1), R^XThe same as the description in the formula (X), represents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom. R^X2Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. n represents an integer of 0to 5. When n is 2 or more, R^X2Optionally identical or different, optionally bonded to each other to form a ring.

R^X2The alkyl group in (1) is not particularly limited as long as it has 1 to 6 carbon atoms, and for example, 1 to 4 carbon atoms are preferable. R^X2Ene of (5)The number of carbon atoms of the group is not particularly limited, and is preferably 2 to 6, for example 2 to 4. When R is^X2When they are bonded to each other to form a ring, R^X2The ring may be formed via an oxygen atom or a sulfur atom. Further, the carbon constituting the ring may form a double bond with an adjacent carbon atom. The number of carbon atoms constituting the ring is not particularly limited, and is, for example, preferably 4 to 12, more preferably 4 to 10, and still more preferably 4 to 6.

In the formula (X2), R^XThe same as the description in the formula (X), represents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom. R^X3And R^X4The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. R^X3And R^X4Optionally bonded to each other to form a ring.

R^X3And R^X4The alkyl group in (1) is not particularly limited as long as it has 1 to 6 carbon atoms, and for example, 1 to 4 carbon atoms are preferable. R^X3And R^X4The number of carbon atoms of the alkenyl group in (1) is not particularly limited, and is preferably 2 to 6, for example. When R is^X3And R^X4When they are bonded to each other to form a ring, R^X3And R^X4The ring may be formed via an oxygen atom or a sulfur atom. Further, the carbon constituting the ring may form a double bond with an adjacent carbon atom. The number of carbon atoms constituting the ring is not particularly limited, and is, for example, preferably 4 to 12, more preferably 4 to 10, and still more preferably 4 to 6.

The monomer represented by the formula (X1) is not particularly limited, and examples thereof include monomers represented by the following formula (X3) and formula (X4).

[ chemical formula 13]

[ chemical formula 14]

In the formula (X3), R^XThe same as the description in the formula (X), represents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom. R^X5And R^X6The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. Furthermore, R^X5And R^X6Optionally bonded to each other to form a ring. R^X5And R^X6The alkyl group of (2) has only to have 1 to 6 carbon atoms, but is not particularly limited, and for example, 1 to 4 carbon atoms are preferable, and 1 to 2 carbon atoms are more preferable. The number of carbon atoms of the alkenyl group is not particularly limited, and is preferably 2 to 6, for example 2 to 4.

In the formula (X4), R^XThe same as the description in the formula (X), represents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom. R^X7And R^X8The same or different, represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. R^X5And R^X6The number of carbon atoms of the alkyl group (b) is not particularly limited as long as it is 1 to 6, and for example, it is preferably 1 to 4, more preferably 1 to 2. The number of carbon atoms of the alkenyl group is not particularly limited as long as it is 2 to 6, and for example, 2 to 4 is preferable.

As a representative example of the monomer represented by the formula (X), a monomer represented by the following formula can be cited.

[ chemical formula 15]

The monomer represented by the above formula (X) can be synthesized by a known method. The production method is not particularly limited, and examples thereof include: comprising a lactone ring in a monomer represented by the formula (X) and-A bonded to the lactone ring¹Alcohols of the-OH group, with R^XEsterification reaction between acrylic anhydride of the radical. The esterification reaction may be preferably carried out in the presence of a base such as diisopropylethylamine, triethylamine, dimethylethylamine, dimethylisopropylamine, diethylmethylamine, or diisopropylmethylamine.

< resin >

The resin of the present invention exhibits high swelling resistance by containing the polymerization unit represented by the formula (Y). Therefore, it can be preferably used as a resin for a photoresist.

[ chemical formula 16]

In the formula (Y), R^X、R^X1、A¹N and m are the same as those described for formula (X), R^XRepresents a halogen atom or an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom. A. the¹Represents a single bond or a linking group. When A is¹When represents a linking group, A¹And R^X1Optionally bonded to each other to form a ring. R^X1Represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. n represents an integer of 0to 5. When n is 2 or more, R^X1Optionally identical or different, optionally bonded to each other to form a ring. m represents an integer of 1 to 4.

The resin of the present invention is not particularly limited as long as it contains a polymerized unit represented by the above formula (Y), and may contain at least one polymerized unit selected from a polymerized unit represented by the following formula (Y1) and a polymerized unit represented by the following formula (Y2), for example.

[ chemical formula 17]

[ chemical formula 18]

In the formulae (Y1) and (Y2), n and R^X、R^X2、R^X3、R^X4The same as those illustrated in formulae (X1) and (X2).

Examples of the polymerization unit represented by the formula (Y1) include: a polymerized unit represented by the following formulae (Y3) and (Y4).

[ chemical formula 19]

[ chemical formula 20]

In the formulae (Y3) and (Y4), R^X、R^X5、R^X6、R^X7And R^X8The same as those illustrated in formulae (X3) and (X4).

The resin of the present invention may have a group (sometimes referred to as an "acid-decomposable group") which is partially eliminated by the action of an acid to form a polar group. Thus, the resin of the present invention has increased polarity by the action of an acid and increased solubility in an alkali developing solution.

Examples of the polar group include: acidic groups such as phenolic hydroxyl group, carboxyl group, fluorinated alcohol group (preferably hexafluoroisopropanol group), sulfonic acid group, sulfonamide group, sulfonylimide group, (alkylsulfonyl) (alkylcarbonyl) methylene group, (alkylsulfonyl) (alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, and tris (alkylsulfonyl) methylene group, alcoholic hydroxyl group, and the like. Among them, preferred are a carboxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), and a sulfonic acid group.

The acid-decomposable group is preferably a group in which a hydrogen atom of the polar group is replaced with a group that can be eliminated by an acid. Examples of the acid-decomposable group include-C (R)^I)(R^II)(R^III)、-C(R^IV)(R^V)(OR^VI) And the like. In the above formula, R^I～R^III、R^VIEach independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R^IVAnd R^VEach independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R^I～R^IIIAt least two groups in (a) may be bonded to each other to form a ring. Furthermore, R^IVAnd R^VThe ring may be bonded to each other to form a ring.

The number of carbon atoms of the acid-decomposable group is not particularly limited, but is preferably 4 or more, and more preferably 5 or more. The upper limit of the number of carbon atoms is not particularly limited, and is preferably 20.

The R is^I～R^VIThe alkyl group (b) is preferably an alkyl group having 1 to 8 carbon atoms, and examples thereof include: methyl, ethyl, propyl, n-butyl, sec-butyl, tert-butyl, hexyl, octyl and the like.

The R is^I～R^VIThe monocyclic hydrocarbon group is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, etc., the polycyclic hydrocarbon group is preferably a cycloalkyl group having 6 to 20 carbon atoms, and examples thereof include adamantyl, norbornyl, isobornyl, bornyl, dicyclopentyl, α -pinenyl, tricyclodecyl, tetracyclododecyl, androstyl, etc., and at least one carbon atom in the cycloalkyl group may be substituted with a heteroatom such as an oxygen atom.

The R is^I～R^VIThe aryl group of (b) is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include: phenyl, naphthyl, anthracenyl, and the like.

The R is^I～R^VIThe aralkyl group (b) is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include: benzyl, phenethyl, naphthylmethyl, and the like.

The R is^I～R^VIThe alkenyl group (b) is preferably an alkenyl group having 2 to 8 carbon atoms, and examples thereof include: vinyl, allyl, butenyl, cyclohexenyl, and the like.

As said R^I～R^IIIA ring formed by bonding at least two groups of (A) to (B), and R^IVAnd R^VThe ring formed by bonding is preferably a cycloalkane ring. As the cycloalkane ring, preferred are: monocyclic cycloalkane rings such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring and a cyclohexane ring; polycyclic cycloalkane rings such as norbornane ring, tricyclodecane ring, tetracyclododecane ring, and adamantane ring.

In addition, R is^I～R^VIThe alkyl group, cycloalkyl group, aryl group, aralkyl group, alkenyl group and the cycloalkane ring in (1) may each have a substituent.

Among the acid-decomposable groups, preferred are tert-butyl groups, tert-amyl groups, and groups represented by the following formulae (I) to (IV).

[ chemical formula 21]

R in the formulae (I) to (IV)²～R⁷、R^aN, p and ring Z¹Respectively represent R in the following formulae (a1) to (a4)²～R⁷、R^aN, p and ring Z¹The same ones.

The acid-decomposable group may be provided via a spacer. As the spacer, the same ones as the linking groups exemplified and described as a in the following formula (1) are shown.

The resin of the present invention preferably contains an acid-decomposable group as a polymerization unit having an acid-decomposable group. Examples of such a polymerization unit having an acid-decomposable group include a polymerization unit represented by the following formula (1).

[ chemical formula 22]

In the above formula (1), R¹Represents the acid-decomposable group. In the formula (1), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group having 1 to 6 carbon atoms include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl and the like. Examples of the alkyl group having 1 to 6 carbon atoms and having a halogen atom include trifluoromethyl group, 2,2, 2-trifluoroethyl group and the likeA group in which one or more hydrogen atoms in the alkyl group are substituted with a halogen atom (halo (C)_1-6) Alkyl), and the like.

In the formula (1), A represents a single bond or a linking group. Examples of the linking group include: carbonyl group (-C (═ O) -), ether bond (-O-), ester bond (-C (═ O) -O-), amide bond (-C (═ O) -NH-), carbonate bond (-O-C (═ O) -O-), a group in which a plurality of these are connected, and a group in which alkylene group and these groups are connected. Examples of the alkylene group include: divalent alicyclic hydrocarbon groups (particularly divalent cycloalkylene groups) such as a linear or branched alkylene group (e.g., a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, or a trimethylene group), 1, 2-cyclopentylene group, 1, 3-cyclopentylene group, cyclopentylidene group, 1, 2-cyclohexylene group, 1, 3-cyclohexylene group, 1, 4-cyclohexylene group, or cyclohexylidene group.

Among the above, the polymer unit represented by the formula (1) preferably contains at least one polymer unit selected from the polymer units represented by the following formulae (a1) to (a 4). In addition, "at least one polymerization unit selected from the polymerization units represented by the above formulae (a1) to (a 4)" may be referred to as a "monomer unit a".

[ chemical formula 23]

In the polymerized units represented by the formulae (a1) to (a4), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, similarly to R in the formula (1), and A represents a single bond or a linking group. A in the formulae (a1) to (a4) is preferably a single bond, or a group in which an alkylene group and a carbonyloxy group are bonded (alkylene-carbonyloxy group). R²～R⁴The same or different alkyl groups each having 1 to 6 carbon atoms and optionally having a substituent. In addition, R is²And R³The ring may be bonded to each other to form a ring. R⁵、R⁶The same or different, represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. R⁷represents-COOR^cGroup R is^cRepresents a tertiary hydrocarbon group optionally having a substituent, a tetrahydrofuranyl group, a tetrahydropyranyl group, or an oxepanyl group. n represents an integer of 1 to 3. When n is 2 or 3, R⁷Each may be the same or different. R^aIs bonded to ring Z¹The substituents of (a) are the same or different and represent an oxo group, an alkyl group, a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, or a carboxyl group optionally protected by a protecting group. p represents an integer of 0to 3. Ring Z¹Represents an alicyclic hydrocarbon ring having 3 to 20 carbon atoms. When p is 2 or 3, R^aOptionally the same or different.

As said R^aExamples of the alkyl group in (1) include: and an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, and an n-hexyl group.

As said R^aThe hydroxyalkyl group in (1) includes, for example: hydroxy group C such as hydroxymethyl, 2-hydroxyethyl, 1-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl and the like_1-6Alkyl groups, and the like.

As said R^aExamples of the protective group optionally contained in the hydroxyl group and the hydroxyalkyl group in (1) include: methyl, ethyl, tert-butyl, etc. C_1-4An alkyl group; a group which forms an acetal bond together with an oxygen atom constituting a hydroxyl group (e.g., C such as methoxymethyl_1-4alkyl-O-C_1-4Alkyl groups); and groups which form an ester bond together with an oxygen atom constituting a hydroxyl group (for example, acetyl group, benzoyl group, and the like).

As said R^aExamples of the protective group for the carboxyl group in (1) include: c such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl and the like_1-6Alkyl, 2-tetrahydrofuryl, 2-tetrahydropyranyl, 2-oxepanyl and the like.

As said R²～R⁶The alkyl group having 1 to 6 carbon atoms in (A) includes, for example: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentylAnd linear or branched alkyl groups such as isopentyl, sec-pentyl, tert-pentyl, and hexyl. Among them, C is preferable_1-4Alkyl, more preferably C_1-3Alkyl, more preferably C_1-2An alkyl group.

As said R²～R⁶Examples of the substituent optionally having an alkyl group having 1 to 6 carbon atoms in (b) include: halogen atom, hydroxy group, substituted hydroxy group (e.g. C such as methoxy, ethoxy, propoxy, etc.)_1-4Alkoxy, etc.), cyano, etc. Examples of the alkyl group having 1 to 6 carbon atoms and having a substituent include: a halogen (C) in which one or more of the hydrogen atoms constituting the alkyl group are substituted with a halogen atom, such as a trifluoromethyl group or a 2,2, 2-trifluoroethyl group_1-6) Alkyl, hydroxymethyl, 2-hydroxyethyl, methoxymethyl, 2-methoxyethyl, ethoxymethyl, 2-ethoxyethyl, cyanomethyl, 2-cyanoethyl and the like.

When R is²And R³When the rings are bonded to each other to form a ring, examples of the ring include alicyclic hydrocarbon rings having 3 to 12 carbon atoms and optionally having a substituent.

As said R^cExamples of the tertiary hydrocarbon group in (1) include a tert-butyl group and a tert-pentyl group.

As said R^cExamples of the substituent optionally having a tertiary hydrocarbon group in (1) include: halogen atom, hydroxy group, substituted hydroxy group (e.g. C such as methoxy, ethoxy, propoxy, etc.)_1-4Alkoxy), cyano, and the like.

As said ring Z¹The alicyclic hydrocarbon ring having 3 to 20 carbon atoms in (b) includes, for example: a cycloalkane ring of about 3 to 20-membered (preferably 3 to 15-membered, particularly preferably 5 to 12-membered) such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, or a cyclooctane ring; a monocyclic alicyclic hydrocarbon ring such as a 3-to 20-membered (preferably 3-to 15-membered, particularly preferably 5-to 10-membered) cycloolefin ring (e.g., a cyclopropene ring, a cyclobutene ring, a cyclopentene ring, or a cyclohexene ring); an adamantane ring; norbornane, norbornene, borane, isoborane, tricyclo [5.2.1.0 ]^2,6]Decane ring, tetracyclo [4.4.0.1^2,5.1^7,10]Dodecane rings and the like containing norbornane rings or norbornane ringsA ring of a bornylene ring; perhydroindene ring, decahydronaphthalene ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ]^3,8]A ring (preferably a fully hydrogenated ring) obtained by hydrogenating a polycyclic aromatic condensed ring such as a tridecane ring or a fully hydrogenated anthracene ring; tricyclic [4.2.2.1 ]^2,5]And bridged hydrocarbon rings having about 2 to 6 rings such as a bicyclic hydrocarbon ring (e.g., a bridged hydrocarbon ring having about 6 to 20 carbon atoms) such as an undecane ring, a tricyclic hydrocarbon ring, and a tetracyclic hydrocarbon ring.

Specific examples of the monomer unit a include monomer units represented by the following formula. In the monomer unit represented by the formula^dRepresents a methyl group or a hydrogen atom, R^eRepresents a methyl group or a hydrogen atom. Furthermore, R^eThe bonding position to the alicyclic hydrocarbon ring is not particularly limited, and one or more R may be used^eBonded to any of the carbon atoms constituting the alicyclic hydrocarbon ring. When the monomer unit represented by the formula has two or more R^eWhen two or more of said R are present^eOptionally the same or different. The monomer unit a may be introduced into the resin by polymerizing the corresponding unsaturated carboxylic acid ester.

[ chemical formula 24]

[ chemical formula 25]

As the polymer unit represented by the above formula (1), in addition to the polymerization unit represented by the above monomer unit a, there can be used a polymerization unit corresponding to an unsaturated carboxylic acid ester containing a lactone ring in which an oxygen atom constituting an ester bond is bonded to the β position of the lactone ring and the α position of the lactone ring has at least one hydrogen atom (except for the polymerization unit corresponding to the monomer unit b described below).

The polymerization unit represented by the above formula (1) may be only one kind, or two or more kinds may be combined. As the polymerization unit represented by the above formula (1), preferred isComprises at least one type of polymerized unit selected from the polymerized units represented by the above formulas (a1) to (a 4). Further, the polymerization unit represented by the above formula (1) may be used in combination with at least one polymerization unit selected from the polymerization units represented by the above formulae (a1) to (a4) and a polymerization unit represented by the above formula (1) (other polymerization unit represented by the formula (1)) other than at least one polymerization unit selected from the polymerization units represented by the above formulae (a1) to (a 4). As the other polymerization unit represented by the formula (1), R is preferable¹Is a polymerized unit represented by the formula (1) of a group having a tertiary hydrocarbon group (for example, a tert-butyl group, a tert-amyl group, etc.).

Further, the resin of the present invention preferably contains a resin having at least [ -C (═ O) -O-]、[-S(＝O)₂-O-]Or [ -C (═ O) -O-C (═ O) -]The alicyclic skeleton of (2). When the alicyclic skeleton is contained, high adhesion to a substrate and etching resistance can be imparted by the resin. The resin of the present invention preferably contains the alicyclic skeleton described above as the polymerized unit having an alicyclic skeleton. It is sometimes said to include]、[-S(＝O)₂-O-]Or [ -C (═ O) -O-C (═ O) -]The polymerized unit of the alicyclic skeleton in (b) is referred to as "monomer unit b". In addition, the monomer units b do not include those belonging to the polymerization unit represented by the formula (Y).

Among the monomer units b, at least one polymerization unit selected from the polymerization units represented by the following formulae (b1) to (b5) is preferably contained (except for those belonging to the polymerization unit represented by the formula (Y)). In the following formulae (b1) to (b5), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom, and A represents a single bond or a linking group. X represents an unbonded group, a methylene group, an ethylene group, an oxygen atom, or a sulfur atom. Y represents a methylene group or a carbonyl group. Z represents a divalent organic group (for example, alkylene (particularly linear alkylene having 1 to 3 carbon atoms) exemplified and described as alkylene optionally contained in A in the polymerization units represented by the formulae (a1) to (a4), or the like¹～V³Same or different and represents-CH₂-、[-C(＝O)-]Or [ -C (═ O) -O-]. And, V¹～V³ToAt least one is [ -C (═ O) -O-]。R⁸～R¹⁴The same or different, represents a hydrogen atom, a fluorine atom, an alkyl group optionally having a fluorine atom, a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group.

[ chemical formula 26]

R, A in the polymerized units represented by formulae (b1) to (b5) is the same as R, A in the polymerized units represented by formulae (a1) to (a 4). R in the polymerization units represented by the formulae (b1) to (b5)⁸～R¹⁴Examples of the alkyl group, the hydroxyl group optionally protected by a protecting group, the hydroxyalkyl group optionally protected by a protecting group, and the carboxyl group optionally protected by a protecting group in (A) and (B) are those related to R in the polymerization units represented by the formulae (a1) to (a4)^aAre the same as those of (1).

As said R⁸～R¹⁴Examples of the alkyl group having a fluorine atom in (1) include: a group in which one or more of hydrogen atoms constituting the alkyl group are substituted with fluorine atoms [ fluoro (C)_1-6) Alkyl radical]And the like.

In the polymerized units represented by the above formulae (b1) to (b4), R⁸～R¹¹Each of the number of the above-mentioned groups may be one or more, preferably 1 to 3. The polymerizable units represented by the formulae (b1) to (b4) each have two or more of the above-mentioned R⁸～R¹¹In the case of (2), two or more of the above-mentioned R⁸～R¹¹Each may be the same or different.

Among the monomer units b, from the viewpoint that excellent substrate adhesion and etching resistance can be imparted to the resin, and that the monomer units are excellent in solubility in an alkali developing solution and that a fine pattern can be formed with high accuracy, it is preferable that: represented by the formula (b1) and R⁸Is cyano, a group having an amide group, a group having an imide group, or fluoro (C)_1-6) Electron-withdrawing group such as alkyl groupThe polymerized units of (a); a polymerized unit represented by the formula (b 2); a polymerized unit represented by formula (b3) and Y is a carbonyl group; a polymerized unit represented by the formula (b 4); and a polymerization unit represented by the formula (b 5).

In the above formula (b1), when R is⁸Is cyano, a group having an amide group, a group having an imide group, or fluoro (C)_1-6) In the case of an electron-withdrawing group such as an alkyl group, the above-mentioned R is particularly preferred⁸At least to the carbon atom marked with x in the above formula (b 1).

Specific examples of the monomer unit b include a polymerized unit represented by the following formula. In the monomer unit represented by the formula^dRepresents a methyl group or a hydrogen atom. The monomer unit b may be introduced into the resin by polymerizing the corresponding unsaturated carboxylic acid ester.

[ chemical formula 27]

[ chemical formula 28]

The resin of the present invention may further have a monomer unit c. The monomer unit c is a polymerization unit represented by the following formula (c 1). When the resin of the present invention contains the monomer unit c as a polymerization unit, high transparency and etching resistance can be imparted by the resin for a photoresist. Wherein R represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms optionally having a halogen atom. A represents a single bond or a linking group. R^bRepresents a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, a carboxyl group optionally protected by a protecting group, or a cyano group, among which, a hydroxyl group and a cyano group are preferable. q represents an integer of 1 to 5. Ring Z²Represents an alicyclic hydrocarbon ring having 6 to 20 carbon atoms. When q is an integer of 2 to 5, 2 to 5R^bEach may be the same or different.

[ chemical formula 29]

Examples of R, A in the polymerized units represented by the formula (c1) include those similar to R, A in the polymerized units represented by the formulae (a1) to (a 4). R in the polymerization unit represented by the formula (c1)^bIn (b), a hydroxyl group optionally protected by a protecting group, a hydroxyalkyl group optionally protected by a protecting group, and a carboxyl group optionally protected by a protecting group are exemplified by those related to R in the polymerization units represented by the formulae (a1) to (a4)^aAre the same as those of (1).

Ring Z in the polymerized unit represented by the formula (c1)²An alicyclic hydrocarbon ring having 6 to 20 carbon atoms, and preferably, for example: a cycloalkane ring of about 6 to 20 membered (preferably 6 to 15 membered, particularly preferably 6 to 12 membered) such as cyclohexane ring and cyclooctane ring; a monocyclic alicyclic hydrocarbon ring such as a 6-to 20-membered (preferably 6-to 15-membered, particularly preferably 6-to 10-membered) cycloolefin ring (e.g., cyclohexene ring); an adamantane ring; norbornane, norbornene, borane, isoborane, tricyclo [5.2.1.0 ]^2,6]Decane ring, tetracyclo [4.4.0.1^2,5.1^7,10]A ring containing a norbornane ring or a norbornene ring, such as a dodecane ring; perhydroindene ring, decahydronaphthalene ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ]^3,8]A ring (preferably a fully hydrogenated ring) obtained by hydrogenating a polycyclic aromatic condensed ring such as a tridecane ring or a fully hydrogenated anthracene ring; tricyclic [4.2.2.1 ]^2,5]And bridged hydrocarbon rings having about 2 to 6 rings such as a bicyclic hydrocarbon ring (e.g., a bridged hydrocarbon ring having about 6 to 20 carbon atoms) such as an undecane ring, a tricyclic hydrocarbon ring, and a tetracyclic hydrocarbon ring. As said ring Z²Among them, a ring containing a norbornane ring or a norbornene ring, and an adamantane ring are preferable.

Specific examples of the monomer unit c include a polymerized unit represented by the following formula. In the polymerized units represented by the formula^dRepresents a methyl group or a hydrogen atom. The monomer unit c may be introduced into the resin by polymerizing the corresponding unsaturated carboxylic acid ester.

[ chemical formula 30]

The resin of the present invention more preferably contains a polymerized unit represented by the above formula (Y) and at least one monomer unit selected from the monomer unit a, the monomer unit b, and the monomer unit c. In this case, the content of the polymerized unit represented by the above formula (Y) in the resin of the present invention is, for example, 5 to 95 mol%, preferably 10 to 90 mol%, more preferably 20 to 80 mol%, and still more preferably 30to 60 mol% based on the total monomer units (polymerized units) constituting the resin. The content of the monomer unit a is, for example, 10 to 90 mol%, preferably 20 to 80 mol%, more preferably 30to 70 mol%, and still more preferably 40 to 60 mol% based on the total monomer units constituting the resin. Further, when the resin of the present invention has the monomer unit b, the content of the monomer unit b is, for example, 0to 80 mol%, preferably 10 to 60 mol%, and more preferably 20 to 50 mol% with respect to the total monomer units constituting the resin. Further, when the resin of the present invention has the monomer unit c, the content of the monomer unit c is, for example, 0to 40 mol%, preferably 1 to 30 mol%, and more preferably 3 to 25 mol% with respect to the total monomer units constituting the resin.

The weight average molecular weight (Mw) of the resin of the present invention is, for example, 1000 to 50000, preferably 2000 to 30000, more preferably 3000 to 20000, and particularly preferably 4000 to 15000. The molecular weight distribution (ratio of weight average molecular weight to number average molecular weight: Mw/Mn) of the resin of the present invention is not particularly limited, but may be 2.5 or less, and is, for example, 1.0 to 2.2, preferably 1.0 to 2.0. In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by GPC using polystyrene as a standard substance, for example, and are preferably measured by the method used in examples.

The acid value of the resin of the present invention is, for example, 0.10mmol/g or less, preferably 0.05mmol/g or less, and more preferably 0.03mmol/g or less. When the acid value is 0.10mmol/g or less, the acid-decomposable group in the resin is protected from being released, and therefore, the resin has excellent resist properties and good stability with time. The lower limit of the acid value is, for example, 0 mmol/g.

< method for producing resin >

The method for producing the resin of the present invention is not particularly limited, and for example, a dropping polymerization method is exemplified. The dropping polymerization method includes, for example, a method of dropping a monomer or a monomer-containing solution in the presence of a polymerization initiator to polymerize the monomer. Specific examples thereof include: [1] a step of dropping a solution containing a polymerization initiator and a monomer; [2] and a step of dropping the monomer or the monomer-containing solution into the polymerization initiator-containing solution. Further, the dropping polymerization method may be carried out in the presence of a chain transfer agent in addition to the polymerization initiator. Examples of the monomer include the monomer of the present invention and monomers corresponding to the monomer unit a, the monomer unit b, and the monomer unit c.

As the polymerization initiator, a known radical polymerization initiator can be used, and examples thereof include azo compounds, peroxide compounds, and redox compounds. Particularly preferred are: dimethyl 2,2 '-azobisisobutyrate, azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), tert-butyl peroxypivalate, di-tert-butyl peroxide, isobutyryl peroxide, lauroyl peroxide, succinic acid peroxide, dicumyl peroxide, di-n-propyl peroxydicarbonate, tert-butyl peroxyallylmonocarbonate, benzoyl peroxide, hydrogen peroxide, ammonium persulfate and the like.

The amount of the polymerization initiator to be used may be an amount necessary for obtaining a resin having a desired molecular weight distribution, and is, for example, 0.05 to 120 mol, preferably 0.1 to 50 mol, and more preferably 0.5 to 10 mol, based on the total amount (100 mol) of the monomers. The amount of the polymerization initiator used is, for example, 0.01 to 30 parts by weight, preferably 0.2 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, based on the total amount (100 parts by weight) of the monomers.

As the chain transfer agent, known chain transfer agents usable in radical polymerization can be used, and examples thereof include mercaptans (n-dodecylmercaptan, n-octylmercaptan, n-butylmercaptan, t-butylmercaptan, n-dodecylmercaptan, mercaptoethanol, mercaptopropanol, triethylene glycol dithiol, etc.), thiol and esters thereof (mercaptopropionic acid, thiobenzoic acid, mercaptoacetic acid, thiomalic acid, etc., and alkyl esters thereof, etc.), alcohols (isopropyl alcohol, etc.), amines (dibutylamine, etc.), hypophosphites (sodium hypophosphite, etc.), α -methylstyrene dimer, terpinolene, myrcene, limonene, α -pinene, β -pinene, etc.

The amount of the chain transfer agent used is not particularly limited, but is preferably 0.001 to 100 moles, more preferably 0.01 to 50 moles, even more preferably 0.1 to 30 moles, and particularly preferably 1 to 10 moles, based on the total amount (100 moles) of the monomers. The amount of the chain transfer agent used is not particularly limited, but is preferably 0.1 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, and still more preferably 1 to 25 parts by weight, based on the total amount (100 parts by weight) of the monomers.

The polymerization step may be carried out without a solvent or in the presence of a polymerization solvent. Examples of the polymerization solvent include: a glycol solvent (the glycol compound), an ester solvent, a ketone solvent, an ether solvent, an amide solvent, a sulfoxide solvent, a monohydric alcohol solvent (the monohydric alcohol compound), a hydrocarbon solvent, a mixed solvent thereof, or the like. Examples of the diol solvent include, in addition to the above diol compounds: propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, and the like. Examples of the ester solvent include: lactate solvents such as ethyl lactate; propionic acid ester solvents such as methyl 3-methoxypropionate; and acetate solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. Examples of the ketone solvent include: acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, and the like. Examples of the ether solvent include: chain ethers such as diethyl ether, diisopropyl ether, dibutyl ether, and dimethoxyethane; tetrahydrofuran, diCyclic ethers such as alkanes. Examples of the amide solvent include N, N-dimethylformamide. Sulfoxide solventsExamples of the agent include dimethyl sulfoxide and the like. Examples of the hydrocarbon solvent include: aliphatic hydrocarbons such as pentane, hexane, heptane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene.

Preferred polymerization solvents include: glycol solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; ester solvents such as ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, and cyclohexanone; and a mixed solvent thereof.

The dropping of the monomer-containing solution may be continuous dropping (a mode of dropping over a certain period of time) or intermittent dropping (a mode of dropping divided into a plurality of times). Further, the dropping speed and the like may be changed more than once during the dropping.

The total dropping time of the monomer-containing solution (time from the start of the dropping to the end of the dropping) varies depending on the polymerization temperature, the kind of the monomer, and the like, and is usually 1 to 10 hours, preferably 2 to 9 hours, and more preferably 3 to 8 hours. The temperature of the monomer-containing solution to be dropped is preferably 40 ℃ or lower. When the temperature of the monomer-containing solution is 40 ℃ or lower, a polymer having an excessively large molecular weight tends to be less likely to be formed at the initial stage of the reaction. In addition, depending on the kind of the monomer, the solution containing the monomer may be excessively cooled to cause crystallization.

The polymerization temperature is not particularly limited, and is, for example, 30to 150 ℃, preferably 50 to 120 ℃, and more preferably 60 to 100 ℃. The polymerization temperature may be changed at least once within the above-mentioned polymerization temperature range during the polymerization.

In the polymerization step, a time for aging may be set after the completion of the dropwise addition. The time for the aging is not particularly limited, and is, for example, preferably 0.5 to 10 hours, and more preferably 1 to 5 hours.

The polymer produced in the polymerization step can be recovered by, for example, precipitation (including reprecipitation). For example, the polymer may be precipitated by adding the polymerization solution (polymer dope) to a solvent (precipitation solvent), or reprecipitated by dissolving the polymer again in an appropriate solvent and adding the solution to a solvent (reprecipitation solvent), or diluted by adding a solvent (reprecipitation solvent, polymerization solvent) to the polymerization solution (polymer dope) to obtain the target polymer. The precipitation or reprecipitation solvent may be any of an organic solvent and water, or may be a mixed solvent.

The precipitation or reprecipitation solvent may be any known or customary solvent, and is not particularly limited. The precipitation or reprecipitation solvent may be the same as or different from the polymerization solvent described above. Examples of the precipitation or reprecipitation solvent include: organic solvents (glycol solvents, ester solvents, ketone solvents, ether solvents, amide solvents, sulfoxide solvents, monohydric alcohol solvents, hydrocarbon solvents) exemplified as the polymerization solvent; halogenated hydrocarbons (halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride; halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene); nitro compounds (nitromethane, nitroethane, etc.); nitriles (acetonitrile, benzonitrile, etc.); carbonates (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.); carboxylic acids (acetic acid, etc.); and mixed solvents containing these solvents.

Among them, the precipitation or reprecipitation solvent is preferably a solvent containing at least a hydrocarbon (particularly, an aliphatic hydrocarbon such as hexane or heptane) or an alcohol (particularly, methanol, ethanol, propanol, isopropanol, butanol, or the like). In such a solvent containing at least hydrocarbon, the ratio of the hydrocarbon (e.g., an aliphatic hydrocarbon such as hexane or heptane) to another solvent (e.g., an ester such as ethyl acetate) is, for example, 10/90 to 99/1, preferably 30/70 to 98/2, more preferably 50/50 to 97/3, in terms of the former/latter ratio (volume ratio: 25 ℃).

Further, as the precipitation or reprecipitation solvent, a mixed solvent of an alcohol (particularly, methanol) and water, and a mixed solvent of a glycol solvent (particularly, polyethylene glycol) and water are also preferable. The ratio (volume ratio; 25 ℃ C.) of the organic solvent (alcohol or glycol solvent) to water in this case is, for example, 10/90 to 99/1 (volume ratio; 25 ℃ C.), preferably 30/70 to 98/2 (volume ratio: 25 ℃ C.), more preferably 50/50 to 97/3 (volume ratio: 25 ℃ C.).

The polymer obtained by precipitation (including reprecipitation) may be subjected to rinsing treatment or washing treatment (sometimes referred to as "repulping treatment") by dispersing the polymer in a solvent and stirring the polymer as necessary. A rinsing treatment may also be performed after the repulping treatment. The residual monomer, low molecular weight oligomer, and the like adhering to the polymer can be effectively removed by repulping and rinsing the polymer produced by polymerization with a solvent.

In the production method of the present invention, the solvent for the repulping treatment and the rinsing treatment is preferably a solvent containing at least a hydrocarbon (particularly, an aliphatic hydrocarbon such as hexane or heptane), an alcohol (particularly, methanol, ethanol, propanol, isopropanol, butanol, or the like), or an ester (particularly, ethyl acetate or the like).

After the precipitation (including reprecipitation), the repulping treatment, or the rinsing treatment, the solvent may be removed by, for example, decantation, filtration, or the like, as necessary, and then a drying treatment may be performed.

< resin composition >

The resin composition of the present invention contains at least the resin of the present invention and a radiation-sensitive acid generator.

As the radiation-sensitive acid generator, a conventional or known compound that efficiently generates an acid by exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, or X-ray can be used, and the compound includes a parent nucleus and the generated acid. Examples of the parent nucleus include: iodine

Onium salts, sulfonium salts (including tetrahydrothiophene)

Salt) of,

Salts, diazonium salts, pyridines

Salt, etc

Salt compounds, sulfonimide compounds, sulfone compounds, sulfonate compounds, disulfonyl diazomethane compounds, disulfonyl methane compounds, oxime sulfonate compounds, hydrazine sulfonate compounds, and the like. Examples of the acid generated by the exposure include: alkyl or fluoroalkyl sulfonic acids, alkyl or fluoroalkyl carboxylic acids, alkyl or fluoroalkyl sulfonimide acids, and the like. These may be used alone or in combination of two or more.

The amount of the radiation-sensitive acid generator to be used may be appropriately selected depending on the strength of the acid generated by irradiation with radiation, the ratio of each repeating unit in the resin, and the like, and may be selected from the range of, for example, 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight, and more preferably 2 to 20 parts by weight, based on 100 parts by weight of the resin.

The resin composition can be prepared, for example, by mixing the resin and a radiation-sensitive acid generator in a solvent for a resist. As the solvent for the resist, a glycol solvent, an ester solvent, a ketone solvent, a mixed solvent thereof, and the like, which are exemplified as the polymerization solvent, can be used.

The resin concentration of the resin composition is, for example, 3 to 40% by weight. The resin composition may also contain an alkali-soluble component such as an alkali-soluble resin (e.g., novolak resin, phenolic resin, imide resin, carboxyl group-containing resin), a colorant (e.g., dye), and the like.

< method for Forming Pattern >

After the resin composition of the present invention is applied to a substrate or a board and dried, a latent image pattern is formed by exposure (or further baking after exposure) to light through a predetermined mask on a coating film (resist film), and then alkali dissolution is performed, whereby a fine pattern having excellent swelling resistance can be formed with high accuracy.

Examples of the substrate or substrate include: silicon wafers, metals, plastics, glass, ceramics, etc. The coating of the resin composition can be carried out by a conventional coating mechanism such as a spin coater, a dip coater, and a roll coater. The thickness of the coating film is, for example, preferably 0.05 to 20 μm, more preferably 0.1 to 2 μm.

For the exposure, radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray can be used.

Upon exposure to light, an acid is generated from the radiation-sensitive acid generator, and a protective group (acid-decomposable group) such as a carboxyl group of a polymerization unit (repeating unit having an acid-decomposable group) which becomes alkali-soluble by the action of the acid in the resin composition is rapidly released by the acid, thereby generating a carboxyl group or the like which contributes to dissolution. Thus, a predetermined pattern can be formed with high accuracy by developing with an alkali developer.