KR20090111276A - A chemically amplified positive resist composition - Google Patents

Abstract

PURPOSE: A chemical amplification positive resist composition is provided to produce excellent pattern profile and form resist membrane with high sweep back angle. CONSTITUTION: A chemical amplification positive resist composition contains a resin A, resin B, acid generating agent. The resin A contains a structure unit with unstable group at side chain The resin A does not contains fluorine element. The resin B contains a structure unit with fluorine-containing group at side chain. The ratio of resin B is less than 2 weight parts based on total weight part.

Description

Chemically Amplified Positive Resist Composition {A CHEMICALLY AMPLIFIED POSITIVE RESIST COMPOSITION}

The present invention relates to a chemically amplified positive resist composition.

Chemically amplified positive resist compositions are used to microfabricate semiconductors.

In particular, how to reduce the defects generated when the semiconductor is microfabricated by the immersion lithography process has been a problem conventionally.

In the case of the liquid immersion lithography method, defects caused by residual water droplets on the resist film are disclosed to be a major problem (for example, CV Peski et al., "Film pulling and meniscus instability as a cause of residual" fluid droplets ", Presentation at the 2nd International Symposium on Immersion Lithography, Sep. 2005, and D. Gil et al.," The Role of Evaporation in Defect Formation in Immersion Lithography ", Presentation at the 2nd International Symposium on Immersion Lithography , Sep. 2005]). This defect is one of defects specific to immersion lithography, and a defect occurs by performing post-exposure baking of a resist film in which water droplets remain.

The number of defects due to water droplets is correlated with the retreat angle on the resist film, and it has been disclosed that defects due to water droplet retention can be reduced by increasing the retreat angle (for example, K. Nakano et. al., "Defectivity data taken with a full-field immersion exposure tool", Presentation at the 2nd International Symposium on Immersion Lithography, Sep. 2005]).

US 2007/0218401 A1 contains, as a chemically amplified resist composition, a structural unit (a1) having an acid labile group in the side chain, but not containing a fluorine atom, and a structure having an acid labile group in the side chain. The structural unit which contains not only 1 type selected from the group which consists of a unit (b1), the structural unit (b3) which has a hydroxyl group in a side chain, and the structural unit (b4) which has a lactone structure in a side chain, but has a fluorine-containing group in a side chain. A composition containing a resin (B) containing (b2) and an acid generator is disclosed. Further, US 2007/0218401 A1 describes the proportion of the resin (B) in a range of 2.04 parts by weight based on 100 parts by weight of the resin (A).

The present invention provides a novel chemically amplified positive resist composition suitable for an immersion lithography process, which is excellent in various resist performances, produces excellent pattern profiles, forms a resist film having a high retreat angle, and has good solubility in a developer. .

The present invention relates to:

<1> Resin (A) containing structural unit (a1) which has a group which is unstable to an acid in a side chain, and does not contain a fluorine atom,

Not only contains one or more selected from the group consisting of a structural unit (b1) having an acid labile group in the side chain, a structural unit (b3) having a hydroxyl group in the side chain and a structural unit (b4) having a lactone structure in the side chain, Resin (B) containing a structural unit (b2) having a fluorine-containing group in the side chain, and

Contains acid generators,

A chemically amplified positive resist composition having a proportion of the resin (B) of 2 parts by weight or less with respect to 100 parts by weight of the resin (A);

The chemically amplified positive resist composition as described in <1> whose ratio which the <2> above-mentioned resin (B) occupies is 0.005 weight part or more and 2 weight part or less with respect to 100 weight part of said resin (A);

<3> The resin (A) contains at least one structural unit selected from the group consisting of a structural unit (a3) having a hydroxyl group and a structural unit (a4) having a lactone structure in addition to the structural unit (a1), or The chemically amplified positive resist composition as described in <2>;

 The chemically amplified positive resist composition according to any one of <1> to <3>, in which the <4> resin (A) contains a structural unit (a3) and a structural unit (a4) in addition to the structural unit (a1);

The chemically amplified positive resist composition according to any one of <1> to <4>, in which the <5> resin (B) contains a structural unit (b1) in addition to the structural unit (b2);

The chemically amplified positive resist as described in any one of <1> to <5> in which the <6> structural units (a1) and (b1) independently represent a structural unit represented by the formula (Ia) or a structural unit represented by the formula (Ib). Composition.

(Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents a C1-C8 alkyl group, R ³ represents a methyl group, n represents an integer of 0 to 14, Z ¹ represents a single bond or-(CH ₂ ) represents a _k- COO- group, where k represents an integer from 1 to 4)

(Wherein R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a C1-C8 alkyl group, and R ⁶ , R ⁷ each independently represent a hydrogen atom or a monovalent C1- which may include one or more heteroatoms). represents a group C8 hydrocarbon or, R ⁶ and R ⁷ are combined with each other to R ⁶ form a ring with the carbon atom and R ⁷ carbon atoms, which is coupled to coupling or, R ^6, which combines the binding carbon atoms and R ^7, which The carbon atom may form a double bond, m represents an integer of 1 to 3, Z ² represents a single bond or a-(CH ₂ ) _{k '} -COO- group, where k' represents an integer of 1 to 4 )

The chemically amplified positive resist composition according to any one of <1> to <6>, in which the <7> structural unit (b3) represents a structural unit represented by the formula (IIb).

(In formula, R <^8> represents a hydrogen atom or a methyl group, R <^9> , R <^10> represents a hydrogen atom, a methyl group, or a hydroxyl group each independently, R <^11> represents a methyl group, n 'represents the integer of 0-12, Z ³ represents a single bond or a-(CH ₂ ) _q -COO- group, where q represents an integer from 1 to 4)

The chemically amplified positive resist composition according to any one of <3> to <7>, in which the <8> structural unit (b3) represents a structural unit represented by the formula (IIa).

(In formula, R <^12> represents a hydrogen atom or a methyl group, R <^13> , R <^14> represents a hydrogen atom, a methyl group, or a hydroxyl group each independently, R <^15> represents a methyl group, n "represents the integer of 0-12, Z ⁴ represents a single bond or a-(CH ₂ ) _{q '} -COO- group, where q' represents an integer from 1 to 4)

The chemically amplified positive type according to any one of <1> to <8>, wherein the <9> structural unit (b4) represents a structural unit represented by the formula (IIIa), (IIIb), (IIIc), (IIId), (IIIe), or (IIIf). Resist composition.

(In formula, R <^17> represents a hydrogen atom or a methyl group, R <^18> represents a methyl group, R <^19> represents a carboxyl group, a cyano group, or C1-C4 hydrocarbon group each independently, R <^20> respectively independently represents a carboxyl group and a cyano group Or a C1-C4 hydrocarbon group, j represents an integer of 0 to 3, a represents an integer of 0 to 5, b represents an integer of 0 to 3, and c represents an integer of 0 to (2j + 2). Z ⁵ represents a single bond or a-(CH ₂ ) _{q "} -COO- group, where q" represents an integer of 1 to 4)

The chemically amplified positive type according to any one of <3> to <9>, wherein the <10> structural unit (a4) represents a structural unit represented by formula IIIg, formula IIIh, formula IIIi, formula IIIj, formula IIIk, or formula IIIl. Resist composition.

(In formula, R <^21> represents a hydrogen atom or a methyl group, R <^22> represents a methyl group, R <^23> represents a carboxyl group, a cyano group, or C1-C4 hydrocarbon group each independently, R <^24> respectively independently represents a carboxyl group and a cyano group Or a C1-C4 hydrocarbon group, i represents an integer of 0 to 3, d represents an integer of 0 to 5, e represents an integer of 0 to 3, f is an integer of 0 to (2i + 2) Z ⁶ represents a single bond or a-(CH ₂ ) _{q "'} -COO- group wherein q"' represents an integer of 1 to 4)

The chemically amplified positive resist composition according to any one of <1> to <10>, in which the <11> structural unit (b2) represents a structural unit represented by the general formula (IV).

(Wherein R ²⁵ represents a hydrogen atom or a methyl group, AR may contain 1 to 5 hydroxyl groups, and may include one or more heteroatoms selected from the group consisting of an oxygen atom, a nitrogen atom, and a sulfur atom); Fluorine-containing alkyl group of C1-C30)

The chemically amplified positive resist composition as described in any one of <1>-<11> whose <12> acid generator is a salt represented by General formula (V).

Wherein R ²⁶ represents a straight or branched hydrocarbon group of C 1 -C 6, or a monocyclic or bicyclic hydrocarbon group of C 3 -C 30, and at least one hydrogen atom in the monocyclic or bicyclic hydrocarbon group is C 1 -C 6 Alkoxy group, C1-C4 perfluoroalkyl group, C1-C6 hydroxyalkyl group, hydroxyl group, cyano group, carbonyl group and ester group, or at least one -CH ₂ -in the monocyclic or bicyclic hydrocarbon group May be substituted with -CO- or -O-, A ⁺ represents an organic counter ion, and Y ¹ , Y ² each independently represent a fluorine atom or a C 1 -C 6 perfluoroalkyl group)

<13> R ²⁶ is a C3-C30 monocyclic or polycyclic hydrocarbon group having a hydroxyl group or a carbonyl group, wherein at least one hydrogen atom in the monocyclic or polycyclic hydrocarbon group is a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1- The chemically amplified positive resist composition as described in <12> which can be substituted by a C4 perfluoroalkyl group, a C1-C6 hydroxyalkyl group, a hydroxyl group, or a cyano group.

The novel chemically amplified positive resist composition of the present invention is excellent in various resist performances, produces an excellent pattern profile, forms a resist film having a high retreat angle, and has good solubility in a developer, which is suitable for the immersion lithography method.

Resin (A) does not contain a fluorine atom. Resin (A) contains the structural unit (a1) which has an acid-labile group in a side chain. Resin (A) may consist of structural unit (a1), and may also contain other structural units or units other than structural unit (a1). Resin (A) preferably contains a structural unit or unit other than the structural unit (a1). As the resin (A), a resin containing at least one structural unit selected from the group consisting of a structural unit (a3) having a hydroxyl group and a structural unit (a4) having a lactone in addition to the structural unit (a1) is more preferable.

Resin (A) may contain 2 or more types of structural units (a1). Resin (A) may contain 2 or more types of structural units (a3). Resin (A) may contain 2 or more types of structural units (a4).

Although the ratio which (a1) occupies among the structural units which comprise resin (A) differs according to the kind of radiation for patterning exposure, the kind of group unstable with an acid, etc., generally 10-80 mol of all the structural units of resin (A). It may be in the range of%.

Although the ratio which (a3) occupies among the structural units which comprise resin (A) differs according to the kind of radiation for patterning exposure, the kind of group unstable with an acid, etc., Preferably it is 0-40 of all the structural units of resin (A). Mol%, More preferably, it may exist in the range of 5-35 mol%.

Although the ratio which (a4) occupies among the structural units which comprise resin (A) differs according to the kind of radiation for patterning exposure, the kind of group unstable with an acid, etc., Preferably it is 0-80 among the whole structural units of resin (A). Mol%, More preferably, it may exist in the range of 10-60 mol%.

The weight average molecular weight of resin (A) is about 1000-500,000 normally using polystyrene as a molecular weight standard, Preferably it is 4,000-50,000.

The resin (B) is at least one member selected from the group consisting of a structural unit (b1) having an acid labile group in the side chain, a structural unit (b3) having a hydroxyl group in the side chain, and a structural unit (b4) having a lactone structure in the side chain. In addition to containing, (b2) a structural unit having a fluorine-containing group in the side chain.

As resin (B), resin containing a structural unit (b1) and a structural unit (b2) is preferable.

Resin (B) can contain 2 or more types of structural units (b1). Resin (B) can contain 2 or more types of structural units (b2). Resin (B) may contain 2 or more types of structural units (b3). Resin (B) can contain 2 or more types of structural units (b4).

In the present invention, when the structural unit has a fluorine-containing group and a hydroxyl group in the side chain, the structural unit is the structural unit (b2).

The proportion of (b1) in the structural units constituting the resin (B) is usually 0.5 mol% to 30 mol%, more preferably 5 mol% to 30 mol% in the total structural units of the resin (B). Can be in.

Although the ratio which (b2) occupies among the structural units which comprise resin (B) changes with the kind of radiation for patterning exposure, the kind of group unstable with an acid, etc., it is 5-99.5 mol% among all the structural units of resin (B). It is preferably in the range of 10 to 95 mol%, more preferably 50 to 90 mol%.

Although the ratio which (b3) occupies among the structural units which comprise resin (B) differs according to the kind of radiation for patterning exposure, the kind of group unstable to an acid, etc., in the whole structural unit of resin (B), Preferably it is 0- 20 mol%, More preferably, it is the range of 0-10 mol%, Especially preferably, it is the range of 0-5 mol%.

Although the ratio which (b4) occupies among the structural units which comprise resin (B) differs according to the kind of radiation for patterning exposure, the kind of group unstable to an acid, etc., among the whole structural units of resin (B), Preferably it is 0-. It may be in the range of 30 mol%, more preferably 0 to 10 mol%, particularly preferably 0 to 5 mol%.

The weight average molecular weight of resin (B) is about 1000-500,000 normally using polystyrene as a molecular weight standard, Preferably it is 4,000-50,000.

The proportion of the resin (B) in the present invention is 2 parts by weight or less, preferably 0.005 parts by weight or more and 2 parts by weight or less, more preferably 0.005 parts by weight or more and 1 parts by weight or less, based on 100 parts by weight of the resin (A), And particularly preferably 0.01 or more and 1 part by weight or less.

As resin (B), resin whose LogP value is 2.10 or more is preferable. Here, the hydrophilic / hydrophobic parameter LogP of the resin refers to the partition coefficient P of the commercial log of the resin, and how the resin is distributed in the equilibrium of a two-phase system containing oil (typically 1-octanol) and water. This value is indicative and can be calculated by the following equation.

LogP = Log (C _oil / C _water )

(Wherein C _oil represents the molar concentration of the resin in the oil phase, and C _water represents the molar concentration of the resin in the water phase)

To evaluate that the LogP values form a structural formula, the LogP values can be experimentally measured and calculated in software in dispensing experiments. In the present invention, the value of LogP of the monomer used to obtain the corresponding structural unit is a program for evaluating the LogP value of Chem Draw Ultra version 9.0.1 manufactured by Cambridge Soft. It can calculate and the LogP value of resin can be calculated by the following formula.

LogP value of resin = Σ (Calculated LogP value of each monomer used to obtain the corresponding structural unit of resin x each composition ratio of corresponding structural unit of resin)

The groups labile to acids in the structural units (a1) and (b1) are cleaved by the acid generated from the acid generator. The acid labile group in the structural unit (a1) may be the same as or different from that of the structural unit (b1).

In the present specification, "ester group" means "structure having an ester of a carboxylic acid". Specifically, "tert-butyl ester group" means "structure having tert-butyl ester of carboxylic acid" and may be described as "-COOC (CH ₃ ) ₃ ".

Examples of an acid labile group include an alkylester group in which a carbon atom adjacent to an oxygen atom is a quaternary carbon atom, an alicyclic ester group in which a carbon atom adjacent to an oxygen atom is a quaternary carbon atom, and a carbon atom adjacent to an oxygen atom is a quaternary carbon atom The structure which has ester of carboxylic acid, such as a lactone ester group, is mentioned. "Quarter carbon atom" means "carbon atom bonded with four substituents besides a hydrogen atom".

Examples of the group labile to an acid include alkyl ester groups in which carbon atoms adjacent to oxygen atoms such as tert-butyl ester groups are quaternary carbon atoms; Methoxymethyl ester, ethoxymethyl ester, 1-ethoxyethyl ester, 1-isobutoxyethyl ester, 1-isopropoxyethyl ester, 1-ethoxypropoxy ester, 1- (2-methoxyethoxy) Ethyl ester, 1- (2-acetoxyethoxy) ethyl ester, 1- [2- (1-adamantyloxy) ethoxy] ethyl ester, 1- [2- (1-adamantanecarbonyloxy) Acetal ester groups such as ethoxy] ethyl ester, tetrahydro-2-furyl ester and tetrahydro-2-pyranyl ester group; Carbon atom quaternary carbon adjacent to oxygen atoms such as isobornyl ester, 1-alkylcycloalkyl ester, 2-alkyl-2-adamantyl ester and 1- (1-adamantyl) -1-alkylalkyl ester group The alicyclic ester group which is an atom is mentioned.

As the structural units (a1) and (b1), structural units derived from an optionally substituted acrylic acid compound are preferable.

As used herein, "optionally substituted acrylic acid compound" means an acrylate, an acrylate in which α-carbon is substituted with a substituent. Examples of the substituents include C1-C4 alkyl groups.

Examples of the optionally substituted acrylic acid compound include acrylate, methacrylate, 2-ethylpropenoate, 2-n-propylpropenoate and 2-n-butylpropenoate.

Examples of the structural units (a1) and (b1) include tert-butyl acrylate, tert-butyl methacrylate, methoxymethyl acrylate, methoxymethyl methacrylate, ethoxymethyl acrylate and ethoxymethyl methacrylate. , 1-ethoxyethyl acrylate, 1-ethoxyethyl methacrylate, 1-isobutoxyethyl acrylate, 1-isobutoxyethyl methacrylate, 1-isopropoxyethyl acrylate, 1-isopropoxyethyl Methacrylate, 1-ethoxypropoxy acrylate, 1-ethoxypropoxy methacrylate, 1- (2-methoxyethoxy) ethyl acrylate, 1- (2-methoxyethoxy) ethyl methacrylate Rate, 1- (2-acetoxyethoxy) ethyl acrylate, 1- (2-acetoxyethoxy) ethyl methacrylate, 1- [2- (1-adamantyloxy) ethoxy] ethyl acrylate , 1- [2- (1-adamantyloxy) ethoxy] ethyl methacrylate, 1- [2- (1-adamantanecarbonyl Ethoxy] ethyl acrylate, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl methacrylate, tetrahydro-2-furyl acrylate, tetrahydro-2-furyl methacrylate , Tetrahydro-2-pyranyl acrylate, tetrahydro-2-pyranyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 1-alkylcycloalkyl acrylate, 1-alkylcycloalkyl methacryl Acrylate, 2-alkyl-2-adamantyl acrylate, 2-alkyl-2-adamantyl methacrylate, 1- (1-adamantyl) -1-alkylalkyl acrylate and 1- (1-adamate) And structural units derived from dandanyl) -1-alkylalkyl methacrylates.

Preferred examples of the structural units (a1) and (b1) include structural units represented by the formula (Ia) (hereinafter simply referred to as structural units (Ia)) and structural units represented by the formula (Ib) (hereinafter simply referred to as structural units (Ib)). It is mentioned.

In the structural unit (Ia), R ¹ represents a hydrogen atom or a methyl group, R ² represents a C1-C8 alkyl group, R ³ represents a methyl group, n represents an integer of 0 to 14, Z ¹ represents a single bond or -(CH ₂ ) _k -COO- group, where k represents an integer of 1 to 4. In the structural unit (Ib), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a C1-C8 alkyl group, and R ⁶ , R ⁷ each independently represent a hydrogen atom or 1 which may include one or more heteroatoms. R ⁶ and R ⁷ are bonded to each other to form a ring together with a carbon atom to which R ⁶ is bonded and a carbon atom to which R ⁷ is bonded, or a carbon atom to which R ⁶ is bonded, and R ⁷ The carbon atoms to which this bond may form a double bond, m represents an integer of 1 to 3, Z ² represents a single bond or a-(CH ₂ ) _{k '} -COO- group, where k' is 1 to 4 Represents an integer.

As an example of a C1-C8 alkyl group, a methyl group, an ethyl group, 1-propyl group, 1-methylethyl group, 1-butyl group, 2-butyl group, 2-methyl-1-propyl group, 1-pentyl group, 2-pentyl group, 2-methyl-1-butyl group, 3-pentyl group, 2,2-dimethyl-1-propyl group, 3-methyl-1-butyl group, 1-hexyl group, 2-hexyl group, 1-heptyl group, 4 -Heptyl group, 1-octyl group, 2-octyl group, 5-methyl-2-heptyl group, cyclopentyl group, 2-methylcyclopentyl group, cyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohex A real group, a 2, 3- dimethyl cyclohexyl group, a 4, 4- dimethyl cyclohexyl group, and a 5-methyl- bicyclic [2.2.1] hept-2-yl group are mentioned, As a C1-C3 alkyl group, a methyl group and an ethyl group are mentioned. And 1-propyl group are mentioned, and 1-methylethyl group is preferable.

Examples of the monovalent C1-C8 hydrocarbon group include methyl group, ethyl group, 1-propyl group, 1-methylethyl group, 1-butyl group, 2-butyl group, 2-methyl-1-propyl group, 1-pentyl group, 2- Pentyl group, 2-methyl-1-butyl group, 3-pentyl group, 2,2-dimethyl-1-propyl group, 3-methyl-1-butyl group, 1-hexyl group, 2-hexyl group, 1-hep Tyl group, 4-heptyl group, 1-octyl group, 2-octyl group, 5-methyl-2-heptyl group, cyclopentyl group, 2-methylcyclopentyl group, cyclohexyl group, 3-methylcyclohexyl group, 4- A methyl cyclohexyl group, a 2, 3- dimethyl cyclohexyl group, and a 4, 4- dimethyl cyclohexyl group are mentioned.

Examples of heteroatoms include oxygen, nitrogen and sulfur atoms.

Examples of the ring formed by bonding R ⁶ and R ⁷ together with the carbon atom to which R ⁶ bonds and the carbon atom to which R ⁷ bonds include a cyclobutane ring, a cyclopentane ring and a cyclohexane ring.

As the structural units (a1) and (b1), the structural unit (Ia) is preferable.

The structural unit (Ia) is derived from the monomer represented by the following formula.

Wherein R ¹ , R ² , R ³ , n and Z ¹ are as defined above.

The structural unit (Ib) is derived from the monomer represented by the following formula.

Wherein R ⁴ , R ⁵ , R ⁶ , R ⁷ , m and Z ² are as defined above.

The following are mentioned as an example of the monomer represented by the said general formula.

Among these monomers, since the resin containing the following structural unit is used in the resist composition of the present invention, since the sensitivity is excellent, 2-alkyl-2-adamantyl acrylate and 2-alkyl-2-adamantyl meta Preferred are acrylate, 1- (2-alkyl-2-adamantyloxycarbonyl) alkyl acrylate and 1- (2-alkyl-2-adamantyloxycarbonyl) alkyl methacrylate, 2-ethyl 2-adamantyl acrylate, 2-ethyl-2-adamantyl methacrylate, 2-isopropyl-2-adamantyl acrylate, 2-isopropyl-2-adamantyl methacrylate and 1 More preferred is-(2-methyl-2-adamantyloxycarbonyl) methylmethacrylate.

2-alkyl-2-adamantyl acrylate can be produced, for example, by reacting 2-alkyl-2-adamantanol or a metal salt thereof with acryloyl halide, and 2-alkyl-2-adamantyl The methacrylate can be produced by, for example, reacting 2-alkyl-2-adamantanol or a metal salt thereof with methacryloyl halide.

 The structural units (a3) and (b3) have hydroxyl groups. The structural units (a3) and (b3) may be the same or different from each other.

As the structural units (a3) and (b3), structural units derived from an optionally substituted acrylic acid compound are preferable. Examples of the optionally substituted acrylic acid compound include those mentioned above.

As the structural unit (a3), a structural unit represented by the formula (IIa) (hereinafter simply referred to as a structural unit (IIa)) is preferable. As the structural unit (b3), a structural unit represented by the formula (IIb) (hereinafter simply referred to as a structural unit (IIb)) is preferable.

In the structural unit (IIa), R ¹² represents a hydrogen atom or a methyl group, R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a methyl group or a hydroxyl group, R ¹⁵ represents a methyl group, and n ″ represents an integer of 0 to 12. represents a, Z ⁴ is a single bond or - _'represents a group -COO-, where _q' (CH ₂₎ q is an integer of 1 to 4 eseo structural units (IIb), R ⁸ is a hydrogen atom or a methyl group , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a methyl group or a hydroxyl group, R ¹¹ represents a methyl group, n 'represents an integer of 0 to 12, Z ³ represents a single bond or-(CH ₂ ) _q- Represents a COO- group, where q represents an integer from 1 to 4.

The structural unit (IIa) is derived from a monomer represented by the following formula

Wherein R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , n "and Z ⁴ are as described above.

The structural unit (IIb) is derived from a monomer represented by the following formula.

Wherein R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , n 'and Z ³ are as described above.

The following are mentioned as a specific example of the monomer represented by the said chemical formula.

Among these monomers, because of excellent sensitivity when a resin containing the following structural unit is used in the resist composition of the present invention, 3-hydroxy-1-adamantyl acrylate and 3,5-dihydroxy-1 -Adamantyl acrylate, 3-hydroxy-1-adamantyl methacrylate, 3,5-dihydroxy-1-adamantyl methacrylate, 1- (3-hydroxy-1-adamant Preference is given to yloxycarbonyl) methyl methacrylate and 1- (3,5-dihydroxy-1-adamantyloxycarbonyl) methyl methacrylate.

3-hydroxy-1-adamantyl acrylate, 3,5-dihydroxy-1-adamantyl acrylate, 3-hydroxy-1-adamantyl methacrylate and 3,5-dihydroxy -1-adamantyl methacrylate can be prepared, for example, by reacting the corresponding hydroxyl-substituted adamantane with acrylic acid, methacrylic acid, or acid halides thereof, and these are also commercially available.

The structural units (a4) and (b4) each have a lactone structure. The structural units (a4) and (b4) may be the same or different from each other.

As the structural units (a4) and (b4), structural units derived from an optionally substituted acrylic acid compound are preferable. Examples of the optionally substituted acrylic acid compound include the same as described above.

As the structural unit (a4), a structural unit represented by the formula (IIIg), (IIIh), (IIIi), (IIIj), (IIIk) or (IIIl) is preferable, and a structural unit represented by the formula (IIIg) and the formula (IIIh) is more preferable.

As structural unit (b4), the structural unit represented by general formula (IIIa), general formula (IIIb), general formula (IIIc), general formula (IIId), general formula (IIIe) or general formula (IIIf) is preferable, and the structural unit represented by general formula (IIIa) and general formula (IIIb) is more preferable.

In the structural unit represented by formula (IIIa), (IIIb), (IIIc), (IIId), (IIIe) or (IIIf), R ¹⁷ represents a hydrogen atom or a methyl group, R ¹⁸ represents a methyl group, and R ¹⁹ each independently represents a carboxyl group or a cyan. A no group or a C1-C4 hydrocarbon group, R ²⁰ each independently represents a carboxyl group, a cyano group or a C1-C4 hydrocarbon group, j represents an integer of 0 to 3, a represents an integer of 0 to 5, b Represents an integer of 0 to 3, c represents an integer of 0 to (2j + 2), Z ⁵ represents a single bond or a-(CH ₂ ) _{q "} -COO- group, where q" represents Represents an integer.

In the structural unit represented by formula (IIIg), formula (IIIh), formula (IIIi), formula (IIIj), formula (IIIk) or formula (IIIl), R ²¹ represents a hydrogen atom or a methyl group, R ²² represents a methyl group, and R ²³ independently represents a carboxyl group, A no group or a C1-C4 hydrocarbon group, each R ²⁴ independently represents a carboxyl group, a cyano group or a C1-C4 hydrocarbon group, i represents an integer of 0 to 3, d represents an integer of 0 to 5, e Represents an integer of 0 to 3, f represents an integer of 0 to (2i + 2), Z ⁶ represents a single bond or a-(CH ₂ ) _{q "'} -COO- group, where q"' represents 1 to The integer of 4 is shown.

Examples of the C1-C4 hydrocarbon group include C1-C4 alkyl groups such as methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, isobutyl group, sec-butyl group and tert-butyl group. And methyl groups are preferred.

The structural units represented by formula (IIIa), (IIIb), (IIIc), (IIId), (IIIe), (IIIf), (IIIg), (IIIh), (IIIi), (IIIj), (IIIk), and (IIIl) are each derived from the corresponding monomers.

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIIa) and general formula (IIIb).

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIIb) and general formula (IIIh).

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIIc) and general formula (IIIi).

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIId) and general formula (IIIj).

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIIe) and general formula (IIIk).

The following are mentioned as a specific example of the monomer used for obtaining the structural unit represented by general formula (IIIf) and general formula (IIIl).

Among these monomers, the following are preferable.

Among the above monomers, acryloyloxy-γ-butyrolactone reacts the corresponding α- or β-bromo-γ-butyrolactone with acrylic acid, or the corresponding α- or β-hydroxy-γ- It can be prepared by reacting butyrolactone and acryloyl halide, methacryloyloxy-γ-butyrolactone is reacted with the corresponding α- or β-bromo-γ-butyrolactone and methacrylic acid Or by reacting the corresponding α- or β-hydroxy-γ-butyrolactone with methacryloyl halides.

Among the above monomers, acrylates and methacrylates of the following alicyclic lactones having a hydroxyl group can be given as examples of the monomers used to obtain the structural units represented by the formulas (IIIb), (IIIc), (IIIh) and (IIIi).

The acrylates and methacrylates of the following alicyclic lactones having the above hydroxyl group are prepared by, for example, reacting the corresponding alicyclic lactones having the hydroxyl group with the acryloyl halide or methacryloyl halide described in JP 2000-26446 A. can do.

The structural unit (b2) has a fluorine-containing group. The structural unit (b2) may have two or more fluorine containing groups.

Examples of the fluorine-containing group include an alkyl group substituted with one or more fluorine atoms, an alkoxy group substituted with one or more fluorine atoms, and an alkoxycarbonyl group substituted with one or more fluorine atoms, and an alkoxy group or an alkoxy substituted with one or more fluorine atoms May be substituted with a group.

The structural unit (b2) may also have one or more hydroxyl groups in addition to the fluorine containing group.

As the structural unit (b2), a structural unit derived from an optionally substituted acrylic acid compound is preferable. Examples of the optionally substituted acrylic acid compound include those mentioned above.

Preferred examples of the structural unit (b2) include a structural unit represented by the formula (IV), hereinafter simply referred to as structural unit (IV).

In the structural unit (IV), R ²⁵ represents a hydrogen atom or a methyl group, AR may contain 1 to 5 hydroxyl groups, and at least one hetero atom selected from the group consisting of an oxygen atom, a nitrogen atom and a sulfur atom The C1-C30 fluorine-containing alkyl group which may contain is shown.

Examples of the C1-C30 fluorine-containing alkyl group include C1-C30 perfluoroalkyl groups such as trifluoromethyl group, pentafluoroethyl group, heptarouropropyl group, and nonafluorobutyl group; C1-C30 perfluoroalkoxyalkyl groups such as 1-trifluoromethoxyethyl group and 1-pentafluoroethoxyethyl group; C1-C30 perfluoroalkoxy perfluoroalkyl groups such as 1-trifluoromethoxydifluoroethyl group and 1-pentafluoroethoxydifluoroethyl group; And the following are mentioned.

In the above formula, straight chains having open ends represent bonds extending from adjacent oxygen groups.

As structural unit (IV), structural units derived from the following monomers are exemplified.

Among these, structural units derived from the following monomers are preferred because of their excellent resolution when a resin containing a structural unit derived from such monomers is used in the resist composition of the present invention.

Resins (A) and (B) may contain other structural units or units than the above structural units. Resin containing a structural unit derived from 2-norbornene exhibits a strong structure because the alicyclic group is present directly on its main chain, and exhibits excellent dry etching resistance.

The structural unit derived from 2-norbornene can be introduced into the main chain by radical polymerization using, for example, aliphatic unsaturated dicarboxylic anhydrides such as maleic anhydride and itaconic anhydride in addition to 2-norbornene. . The structural unit derived from 2-norbornene is formed by opening its double bond and can be represented by the formula (d).

Wherein R ⁵⁵ and R ⁵⁶ are each independently a hydrogen atom, a C1-C3 alkyl group, a C1-C3 hydroxyalkyl group, a carboxyl group, a cyano group or -COOU ¹ (U ¹ being an alcohol moiety, Or R ⁵⁵ and R ⁵⁶ are joined together to form a carboxylic anhydride residue represented by -C (= 0) OC (= 0)-).

The structural units derived from maleic anhydride and the structural units derived from itaconic anhydride, which are structural units derived from aliphatic unsaturated dicarboxylic anhydrides, are formed by the opening of their double bonds, Can be represented.

In R ⁵⁵ and R ⁵⁶ , examples of the C1-C3 alkyl group include methyl group, ethyl group, 1-propyl group and isopropyl group, and examples of C1-C3 hydroxyalkyl group include hydroxymethyl group and 2-hydroxyethyl group. .

In R ⁵⁵ and R ⁵⁶ , the -COOU ¹ group is an ester formed from a carboxyl group, and examples of the alcohol residue corresponding to U ¹ include an optionally substituted primary or secondary alkyl group having 1 to 8 carbon atoms, 2-oxooxolane-3- And 2-oxooxolan-4-yl. As an example of the substituent on the said alkyl group, a hydroxyl group and an alicyclic hydrocarbon residue are mentioned.

Specific examples of the monomer used to obtain the structural unit represented by the formula (d) include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene-2-carboxylic acid, methyl 5-norborne Nene-2-carboxylate, 2-hydroxyethyl 5-norbornene-2-carboxylate, 5-norbornene-2-methanol, 5-norbornene-2,3-dicarboxylic anhydride Etc. can be mentioned.

The structural unit represented by the formula (g) is a structural unit having an acid labile group such as a norbornene structure, and the structural units (a1) and (b1) also include structural units represented by the formula g.

Wherein any one of R ⁵⁷ and R ⁵⁸ represents -COOU ² (U ² represents an acid labile group), the other represents a hydrogen atom, an alkyl group of C 1 -C 3, a hydroxyalkyl group of C 1 -C 3, a carboxyl group , Cyano group or -COOU ³ (U ³ is an alcohol moiety)

Examples of the monomer providing the structural unit represented by the formula g include t-butyl 5-norbornene-2-carboxylate, 1-cyclohexyl-1-methylethyl 5-norbornene-2-carboxylate, 1-methylcyclohexyl 5-norbornene-2-carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-nor Bornen-2-carboxylate, 1- (4-methylcyclohexyl) -1-methylethyl 5-norbornene-2-carboxylate, 1- (4-hydroxycyclohexyl) -1-methyl Ethyl 5-norbornene-2-carboxylate, 1-methyl-1- (4-oxocyclohexyl) ethyl 5-norbornene-2-carboxylate, 1- (1-adamantyl) -1 -Methylethyl 5-norbornene-2-carboxylate, etc. are mentioned.

The structural unit represented by the formula h is a structural unit having a fluorine-containing group, and the structural unit (b2) also includes the structural unit represented by the formula h.

[Wherein any one of R ⁵⁹ and R ⁶⁰ is a C1-C3 fluorine-containing alkyl group, a C1-C3 fluorine-containing hydroxyalkyl group or a -COOU ⁴ group (U ⁴ represents a fluorine-containing alcohol residue, provided that Residues are not acid labile groups), the other being a hydrogen atom, a C1-C3 alkyl group which may be substituted with one or more fluorine atoms, a C1-C3 hydroxyalkyl group that may be substituted by one or more fluorine atoms, a carboxyl group, a cya Nogi or -COOU ⁵ group (U ⁵ represents an alcohol moiety, except that the alcohol moiety is not an acid labile group)

Resin (A) and (B) can be manufactured, for example by superposing | polymerizing the corresponding monomer or monomer. In addition, the resins (A) and (B) can be prepared by carrying out the oligomerization of the corresponding monomer or monomer and then polymerizing the oligomer obtained.

For example, the resin (A) containing the structural unit (Ia), the structural unit (IIa) and the structural unit represented by the formula (IIIh) as the structural unit (a1), the structural unit (a3) and the structural unit (a4), respectively, For example, it can manufacture by superposing | polymerizing the monomer used for obtaining a structural unit (Ia), the monomer used for obtaining a structural unit (IIa), and the monomer used for obtaining the structural unit represented by general formula (IIIh).

For example, as the structural unit (b1), the structural unit (b3), the structural unit (b4) and the structural unit (b2), the structural unit and the structure represented by the structural unit (Ib), the structural unit (IIb), and the general formula (IIIb), respectively Resin (B) containing unit (IV) is, for example, a monomer used to obtain structural unit (Ib), a monomer used to obtain structural unit (IIb), a monomer used to obtain structural unit represented by formula IIIb. And the monomers used to obtain the structural unit (IV).

The polymerization reaction is usually carried out in the presence of a radical initiator.

The radical initiator is not particularly limited, and examples thereof include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane -1-carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl- Azo compounds such as 2,2'-azobis (2-methylpropionate) and 2,2'-azobis (2-hydroxymethylpropionitrile); Lauryl peroxide, tert-butylhydroperoxide, benzoyl peroxide, tert-butylperoxybenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, tert- Organic peroxides such as butyl peroxy neodecanoate, tert-butyl peroxy pivalate and 3,5,5-trimethylhexanoyl peroxide; Inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide and the like. Especially, an azo compound is preferable, 2,2'- azobisisobutyronitrile, 2,2'- azobis (2-methylbutyronitrile), 1,1'- azobis (cyclohexane-1- Carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) and dimethyl-2,2'-azobis (2-methylpropionate) are more preferred, and 2,2'-azo More preferred are bisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile).

These radical initiators may be used alone or in combination of two or more thereof. When using two types together, the mixing ratio is not specifically limited. In addition, when these 2 types are used together, the combination of 2,2'- azobisisobutyronitrile and 2,2'- azobis (2, 4- dimethylvaleronitrile), 2,2'- azobis ( 2,4-dimethylvaleronitrile) and 2,2'-azobis (2-methylbutyronitrile) in combination, 2,2'-azobis (2,4-dimethylvaleronitrile) and 1,1 Combination with '-azobis (cyclohexane-1-carbonitrile) and 2,2'-azobis (2,4-dimethylvaleronitrile) and dimethyl-2,2'-azobis (2-methylprop Cationate) is preferred.

As for the usage-amount of the said radical initiator, 1-20 mol% is preferable with respect to monomer or oligomer total amount.

The said polymerization reaction temperature is the range of 0-150 degreeC normally, Preferably it is the range of 40-100 degreeC.

The polymerization reaction is carried out in the presence of a solvent, and it is preferable that such a solvent can dissolve all of a monomer, a radical initiator, and a resin obtained. As such an example, Hydrocarbon solvents, such as toluene; Ether solvents such as 1,4-dioxane and tetrahydrofuran; Ketone solvents such as methyl isobutyl ketone; Alcohol solvents such as isopropyl alcohol; cyclic ester solvents such as γ-butyrolactone; Glycol ether ester ester solvents such as propylene glycol monomethyl ether acetate; And acyclic ester solvents such as ethyl lactate. These solvents may be used alone or in combination of two or more thereof.

Although the usage-amount of the said solvent is not specifically limited, 1-5 weight part is preferable with respect to the monomer or oligomer total amount.

When alicyclic compounds having an olefinic double bond and aliphatic unsaturated dicarboxylic anhydrides are used as monomers, it is preferable to use them in excess in view of the tendency that they are not easily neutralized.

After completion of the polymerization reaction, the produced resin can be isolated by, for example, filtering the precipitated resin by adding a solvent in which the resin of the present invention is insoluble or poorly soluble. If desired, the isolated resin can be purified, for example, by washing with a suitable solvent.

The chemically amplified positive resist composition of the present invention contains an acid generator. In the case where the resin (B) contains the structural unit (b1), the acid generated by irradiating the composition chemically acts on the acid-labile groups of the resin (A) and the resin (B) to cleave the group that is unstable with the acid. Becomes soluble in aqueous alkali solution.

The resist composition of the present invention usually contains 80 to 99.9% by weight of the total amount of the resin (A) and the resin (B) and 0.1 to 20% by weight of the acid generator with respect to the total solid amount of the composition of the present invention.

As a specific example of an acid generator, the salt represented by general formula (V) is mentioned.

(Hereinafter simply referred to as salt (V))

In the salt (V), Y ¹ and Y ² each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group. Examples of the C1-C6 perfluoroalkyl group include trifluoromethyl group, pentafluoroethyl group, heptarouropropyl group, nonafluorobutyl group, and perfluorohexyl group. Y ¹ and Y ² are each independently a fluorine atom or a trifluoromethyl group. Y ¹ and Y ² are preferably the same group.

In salt (V), R ²⁶ represents a C1-C6 straight or branched hydrocarbon group, or C3-C30 monocyclic or bicyclic hydrocarbon group, wherein at least one hydrogen atom in the monocyclic or bicyclic hydrocarbon group is C1 At least one —CH in the monocyclic or bicyclic hydrocarbon group which may be substituted by an alkoxy group of C 6, a perfluoroalkyl group of C 1 -C 4, a hydroxyalkyl group of C 1 -C 6, a hydroxyl group, a cyano group, a carbonyl group and an ester group ₂ -may be substituted with -CO- or -O-, A ⁺ represents an organic counter ion, and Y ¹ , Y ² each independently represent a fluorine atom or a C 1 -C 6 perfluoroalkyl group.

R ²⁶ is preferably a C3-C30 monocyclic or polycyclic hydrocarbon group having a hydroxyl group or a carbonyl group, wherein at least one hydrogen atom in the monocyclic or polycyclic hydrocarbon group is a C1-C6 alkyl group, a C1-C6 alkoxy group, a C1- It may be substituted with a C4 perfluoroalkyl group, a C1-C6 hydroxyalkyl group, a hydroxyl group or a cyano group.

Examples of the C1-C6 linear or branched hydrocarbon group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-hex Practical skills can be mentioned. Examples of the C1-C6 alkoxy group are methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group and n -Hexyloxy group is mentioned.

Examples of the C1-C4 perfluoroalkyl group include trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group and nonafluorobutyl group. As an example of C1-C6 hydroxyalkyl group, a hydroxymethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, and 4-hydroxybutyl group are mentioned. As an example of an ester group, a methoxycarbonyl group, an ethoxycarbonyl group, and 2-oxotetrahydrofuran-3-yl group are mentioned. Examples of the C1-C6 perfluoroalkyl group include trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, nonafluorobutyl group, undecafluoropentyl group, and tridecafluorohexyl group.

Examples of the C3-C30 monocyclic or bicyclic hydrocarbon group having a hydroxyl group or a carbonyl group include a C4-C8 cycloalkyl group having a hydroxyl group or a carbonyl group, an adamantyl group having a hydroxyl group or a carbonyl group, and a norbornyl group having a hydroxyl group or a carbonyl group.

As specific examples of these, 2-oxocyclopentyl group, 2-oxocyclohexyl group, 3-oxocyclopentyl group, 3-oxocyclohexyl group, 4-oxocyclohexyl group, 2-hydroxycyclopentyl group, 2- Hydroxycyclohexyl group, 3-hydroxycyclopentyl group, 3-hydroxycyclohexyl group, 4-hydroxycyclohexyl group, 4-oxo-2-adamantyl group, 3-hydroxy-1-adamantyl group , 4-hydroxy-1- adamantyl group, 5-oxonorbornane-2-yl group, 1,7,7-trimethyl-2-oxonorbornan-2-yl group, 3,6,6-trimethyl- 2-oxobicyclo [3.1.1] hept-3-yl group, 2-hydroxynorbornan-3-yl group, 1,7,7-trimethyl-2-hydroxynorbornan-3-yl group, 3, 6,6-trimethyl-2-hydroxybicyclo [3.1.1] hept-3-yl group, and the following.

In the above formula, straight chains having open ends represent bonds extending from adjacent groups.

The following are mentioned as a special example of the anion part of salt (V).

Specific examples of the anion moiety include the following ones.

Other examples of acid generators include salts represented by the general formula (VIII) (hereinafter simply referred to as salts (VIII)).

Wherein A ⁺ is the same as described above and R ²⁷ is a C1-C6 linear or branched perfluoroalkyl group

Specific examples of the anion portion of the salt (VIII) include trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion and nonafluorobutanesulfonate anion.

Examples of the organic counterion represented by A ⁺ include cations represented by the formulas IXz, IXb, IXc, and IXd.

In the cation represented by the formula (IXz), P ^a , P ^b and P ^c are each independently a C1-C30 alkyl group which may be substituted with one or more selected from the group consisting of a hydroxyl group and a C1-C12 alkoxy group, or a hydroxyl group and a C1-C12 C3-C30 cyclic hydrocarbon group which may be substituted by one or more selected from the group consisting of alkoxy groups is shown.

Examples of the C1-C30 alkyl group represented by the formula (IXz) include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, see-butyl, tert-butyl, n-pentyl and n-hex. The actual group, n-octyl group, and 2-ethylhexyl group are mentioned. Examples of the C1-C12 alkoxy group represented by the formula (IXz) include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n-pentylocta A time period, n-hexyloxy group, n-octyloxy group, and 2-ethylhexyloxy group are mentioned. Examples of the C3-C30 cyclic hydrocarbon group include cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, bicyclohexyl group, phenyl group, 2-methylphenyl group, 4-methylphenyl group and 4-ethylphenyl group , 4-isopropylphenyl group, 4-tert-butylphenyl group, 2,4-dimethylphenyl group, 2,4,6-trimethylphenyl group, 4-n-hexylphenyl group, 4-n-octylphenyl group, 1-naphthyl group, 2 -A naphthyl group, a fluorenyl group, and a biphenyl group are mentioned.

In the general formula (IXb), P ⁴ and P ⁵ each independently represent a hydrogen atom, a hydroxyl group, a C1-C12 alkyl group or a C1-C12 alkoxy group. Examples of the C1-C12 alkyl group represented by the formula (IXb) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-hexyl group , n-octyl group and 2-ethylhexyl group, and examples of the C1-C12 alkoxy group represented by the general formula (IXb) include the same groups as described in the general formula (IXz).

In formula (IXc), P ⁶ and P ⁷ each independently represent a C1-C12 alkyl group or a C3-C12 cycloalkyl group, or P ⁶ and P ⁷ are bonded to form a C3-C12 divalent hydrocarbon group to form an adjacent S ⁺ group. Together, they form a ring, and at least one -CH ₂ -of the divalent hydrocarbon group may be substituted with -CO-, -O-, or -S-.

P ⁸ represents a hydrogen atom, P ⁹ represents an optionally substituted C1-C12 alkyl group, a C3-C12 cycloalkyl group or an aromatic group, or P ⁸ and P ⁹ join to form a divalent hydrocarbon group together with adjacent -CHCO- Forms a 2-oxocycloalkyl group, and at least one -CH ₂ -of the divalent hydrocarbon group may be substituted with -CO-, -O- or -S-.

Examples of the C1-C12 alkyl group of the formula (IXc) include the same groups as mentioned in the formula (IXb), and examples of the C1-C12 cycloalkyl group of the formula (IXc) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclohep A methyl group, a cyclooctyl group, and a cyclodecyl group are mentioned. As an example of the C3-C12 divalent hydrocarbon group, the divalent C3-C12 hydrocarbon group formed by the bonding of P ⁶ and P ^{7 includes a} trimethylene group, a tetramethylene group, a pentamethylene group, and adjacent S ⁺ and a divalent hydrocarbon group. Examples of the cyclic group formed together with a hydrocarbon group include tetramethylene sulfonio, pentamethylene sulfonio and oxybisethylene sulfonio.

Examples of the aromatic group of the formula (IXc) include a phenyl group, tolyl group, xylyl group and naphthyl group. Examples of the divalent hydrocarbon group formed by bonding of P ⁸ and P ⁹ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group and a pentamethylene group, and adjacent -CHCO- in combination with P ⁸ and P ⁹ are bonded to each other. Examples of the 2-oxocycloalkyl group formed include 2-oxocyclopentyl group and 2-oxocyclohexyl group.

In formula (IXd), P ¹⁰ , P ¹¹ , P ¹² , P ¹³ , P ¹⁴ , P ¹⁵ , P ¹⁶ , P ¹⁷ , P ¹⁸ , P ¹⁹ , P ²⁰ and P ²¹ are each independently a hydrogen atom, a hydroxyl group, C1- A C12 alkyl group or a C1-C12 alkoxy group, B represents a sulfur or an oxygen atom, and r represents 0 or 1.

Examples of the C1-C12 alkyl group of the formula (IXd) include the same groups as mentioned in the above formula (IXb), and examples of the C1-C12 alkoxy group of the formula (IXd) include the same groups as mentioned in the formula (IXz).

The following are mentioned as an example of the cation represented by general formula (IXz).

In the organic cation represented by the formula (IXz), the cation represented by the formula (IXa) is preferable.

(Wherein P ¹ , P ² and P ³ each independently represent a hydrogen atom, a hydroxyl group, a C1-C12 alkyl group or a C1-C12 alkoxy group)

In the cation represented by the formula (IXa), the cation represented by the formula (IXe) is preferable.

Wherein P ²² , P ²³ and P ²⁴ each independently represent a hydrogen atom or a C1-C4 alkyl group

In formula (IXa), P ¹ , P ² and P ³ each independently represent a hydrogen atom, a hydroxyl group, a C 1 -C 12 alkyl group or a C 1 -C 12 alkoxy group, and examples of the C 1 -C 12 alkyl group include the same groups as mentioned in the above formula (IXb) And examples of the C 1 -C 12 alkoxy group include the same groups as mentioned in the general formula (IXz).

In formula (IXe), P ²² , P ²³ and P ²⁴ each independently represent a hydrogen atom or a C1-C4 alkyl group, and examples of the C1-C4 alkyl group include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, Isobutyl group, see-butyl group, and tert- butyl group are mentioned.

As an example of the cation represented by general formula (IXb), the following are mentioned.

Examples of the cation represented by the formula (IXc) include the following ones.

As an example of the cation represented by general formula (IXd), the following are mentioned.

As the organic counterion, the cation represented by the formula (IXe) is preferable.

The said salt can be used individually or in combination of 2 or more types.

As acid generators, salts represented by formula (Xa), formula (Xb) or formula (Xc) are preferred in that they improve resolution and pattern profile.

Wherein P ²⁵ , P ²⁶ and P ²⁷ each independently represent a hydrogen atom or a C1-C4 alkyl group, and P ²⁸ and P ²⁹ each independently represent a C1-C12 alkyl group or a C3-C12 cycloalkyl group, or P ²⁸ and P ²⁹ combine to form a bivalent hydrocarbon group of C 3 -C 12 to form a ring with adjacent S ⁺ , P ³⁰ represents a hydrogen atom, P ³¹ is an optionally substituted C 1 -C 12 alkyl group, C 3- C12 cycloalkyl group or aromatic group, or P ³⁰ and P ³¹ combine to form a divalent hydrocarbon group of C3-C12 to form a 2-oxocycloalkyl group together with adjacent -CHCO-, At least one -CH ₂ -of the divalent hydrocarbon group may be substituted with -CO-, -O- or -S-, and Y ²¹ , Y ²² , Y ³¹ and Y ³² are each independently a fluorine atom or C 1- A C6 perfluoroalkyl group.

Acid generators can be prepared according to known methods such as JP 2007-249192 A.

In the resist composition of the present invention, by adding an organic base compound, especially a nitrogen-containing organic base compound, as a quenching agent, it is possible to reduce performance deterioration due to deactivation of an acid due to post-exposure delay.

Specific examples of the nitrogen-containing organic base compound include an amine compound represented by the following chemical formula.

[Wherein T ¹ and T ² independently represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, the alkyl, cycloalkyl and aryl groups being a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and C1-C6 alkoxy Optionally substituted with one or more groups selected from the group consisting of groups (optionally substituted with a C1-C6 alkoxy group),

T ³ and T ⁴ independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group, said alkyl group, cycloalkyl group, aryl group and alkoxy group being a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and C1- Optionally substituted with one or more groups selected from the group consisting of C6 alkoxy groups, or T ³ and T ⁴ combine with the carbon atoms to which they are attached to form an aromatic ring,

T ⁵ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or a nitro group, wherein the alkyl group, cycloalkyl group, aryl group and alkoxy group are hydroxyl group, amino group (optionally substituted with C1-C4 alkyl group) and C1-C6 alkoxy Optionally substituted with one or more groups selected from the group consisting of groups,

T ⁶ represents an alkyl group or a cycloalkyl group, wherein said alkyl group and cycloalkyl group are optionally substituted with one or more groups selected from the group consisting of a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and a C1-C6 alkoxy group,

A ¹ is —CO—, —NH—, —S—, —SS—, an alkylene group (at least one methylene group is optionally substituted with —O—), or an alkenylene group (at least one methylene group is —O— and Optionally substituted with quaternary ammonium hydroxide represented by the following formula).

[In formula, T <^1> , T <^2> and T <^6> are as above-mentioned, T <^7> represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, The said alkyl group and a cycloalkyl group are substituted by a hydroxyl group and an amino group (C1-C4 alkyl group optionally). And one or more groups selected from the group consisting of C1-C6 alkoxy groups, said aryl groups being hydroxyl groups, amino groups (optionally substituted with C1-C4 alkyl groups), C1-C6 alkoxy groups and C1-C4 perfluoroalkyl groups Optionally substituted with one or more groups selected from the group consisting of

^{T 1, T 2, T 3} , T 4, T 5, T 6 and T ⁷ is the carbon number of the alkyl group of 1 to 10 are preferred, more preferably about 1 to 6

Examples of the amino group optionally substituted with a C1-C4 alkyl group include an amino group, methylamino group, ethylamino group, n-butylamino group, dimethylamino group and diethylamino group. Examples of the C1-C6 alkoxy group optionally substituted with a C1-C6 alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, tert-butoxy group, n-pentyloxy group, n- Hexyloxy group and 2-methoxyethoxy group are mentioned.

Specific examples of the alkyl group optionally substituted with one or more groups selected from the group consisting of a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and a C1-C6 alkoxy group (optionally substituted with a C1-C6 alkoxy group) include methyl, ethyl, n -Propyl group, isopropyl group, n-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, 2- (2-methoxy Ethoxy) ethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2-aminoethyl group, 4-aminobutyl group, and 6-aminohexyl group are mentioned.

^{T 1, T 2, T 3} , T 4, T 5, T 6 and T ⁷ carbon atoms of a cycloalkyl group is preferably a 5 to 10 degree. Specific examples of the cycloalkyl group optionally substituted with one or more groups selected from the group consisting of a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and a C1-C6 alkoxy group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. The group can be mentioned.

^{T 1, T 2, T 3} , T 4 and T ⁵ of the carbon atoms of the aryl group is preferably 6 to 10 or so. Specific examples of the aryl group optionally substituted with one or more groups selected from the group consisting of a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group) and a C1-C6 alkoxy group include a phenyl group and a naphthyl group.

As for carbon number of the aryl group of T <^7> , about 6-10 are preferable. Specific examples of the aryl group optionally substituted with one or more groups selected from the group consisting of a hydroxyl group, an amino group (optionally substituted with a C1-C4 alkyl group), a C1-C6 alkoxy group and a C1-C4 perfluoroalkyl group include a phenyl group, a naphthyl group and 3-trifluoromethylphenyl group is mentioned.

T ^3, T ⁴ and T ⁵ of the carbon atoms of the alkoxy group is from 1 to about 6 are preferred, and specific examples thereof, methoxy, ethoxy, n- propoxy, iso-propoxy, n- butoxy, tert- Butoxy group, n-pentyloxy group, n-hexyloxy group is mentioned.

As for carbon number of the alkylene and alkenylene group of A <^1> , 2-6 are preferable. Specific examples of the alkylene group include ethylene group, trimethylene group, tetramethylene group, methylenedioxy group and ethylene -1,2-dioxy group. Specific examples of the alkenylene group include ethane-1,2-diyl group and 1-. And propane-1,3-diyl and 2-butane-1,4-diyl groups.

Specific examples of the amine compound include n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 1-naphthylamine, 2-naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-dia Mino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine , Dinonylamine, didecylamine, N-methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, tri Octylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldi Neilamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,6-diisopropylaniline, imidazole, benzimidazole, pyridine, 4-methylpyridine, 4 -Methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridylketone, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl ) Ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-bis (4- Pyridyloxy) ethane, 4,4'-dipyridylsulfide, 4,4'-dipyridyldisulfide, 1,2-bis (4-pyridyl) ethylene, 2,2'-dipicolylamine, 3 , 3'-dipicolylamine, etc. are mentioned.

Examples of quaternary ammonium hydroxides are tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethylphenyl ) Trimethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (so-called "choline"), etc. are mentioned.

Moreover, the hindered amine compound which has a piperidine skeleton as disclosed in Unexamined-Japanese-Patent No. 11-52575 can also be used.

In terms of forming a pattern with high resolution, quaternary ammonium hydroxide is preferably used as a quenching agent. The content of the quenching agent in the resist composition of the present invention may be contained in 0.01 to 1% by weight based on the total solids of the composition. In the present invention, the total solids means the total amount excluding the solvent.

The resist composition of the present invention may contain a small amount of various additives such as sensitizers, dissolution inhibitors, other polymers, surfactants, stabilizers, and dyes as necessary, so long as the effects of the present invention are not impaired.

The resist composition of the present invention is usually applied by a conventional method such as spin coating on a substrate such as a silicon wafer in a state in which each of the above components is dissolved in a solvent. The solvent used here should just melt | dissolve each said component sufficiently, have a moderate drying speed, and provide a uniform and smooth coating film after a solvent evaporates, The solvent generally used in this field can be used.

For example, glycol ether esters, such as ethyl cellosolve acetate, methyl cellosolve acetate, and a propylene glycol monomethyl ether acetate; Acyclic esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; Ketones such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone; Cyclic ester, such as (gamma) -butyrolactone, etc. are mentioned. These solvents can be used individually or in combination of 2 or more types.

The resist film coated on the substrate and dried is subjected to an exposure treatment for patterning, and then subjected to a heat treatment for promoting the deprotecting group reaction, followed by development with an alkaline developer. The alkaline developer used herein may be various alkaline aqueous solutions used in this field, and examples thereof include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as "choline"). Can be.

<Example>

The embodiments disclosed herein are illustrated in all aspects, but should not be considered as limiting. The scope of the invention is to be determined by the claims rather than the foregoing description, and all equivalents of the claims and equivalents thereof shall be considered to be included.

Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples. "%" And "parts" indicating the amount of the optional component and the amount of the optional substance used in the following examples are by weight unless otherwise specified. In addition, the average molecular weight of the arbitrary material of the following Example is the value calculated | required by the gel permeation chromatography using polystyrene (made by Tosoh Corporation) as a molecular weight standard [column (three columns + guard column): TSK gel Multipore H _X1 -M (manufactured by Tosoh Corporation) eluent: tetrahydrofuran, flow rate: 1.0 mm / min, detector: RI detector, column temperature: 40 ℃, injection amount: 100 ㎕].

The monomer used in the Example is the following monomers A-F.

Resin Synthesis Example 1 (Synthesis of Resin A1)

70.91 parts of methyl isobutyl ketones were thrown into the four neck flask equipped with the thermometer and the reflux tube, and it bubbling with nitrogen gas for 30 minutes. 30 parts of monomer E, 14.27 parts of monomer F, 10.28 parts of monomer G (monomer ratio; monomer E: monomer F: monomer G = 50: 25: 25) under a nitrogen gas atmosphere, 2,2'-azobisisobutyronitrile 0.79 The solution which mixed 70.19 parts of methyl isobutyl ketones was dripped at 86 degreeC over 1 hour. The resulting mixture was kept at 86 ° C. for 5 hours. After cooling, the reaction solution was poured into 815 parts of n-heptane with stirring, the precipitated resin was collected by filtration, and the filtrate was washed three times with 407 parts of n-heptane. The obtained resin was dried under reduced pressure to obtain 25.4 parts of resin A1. Yield: 55%, Mw: 9,400, Mw / Mn: 1.52.

The resin has the following structural unit.

Resin Synthesis Example 2 (Synthesis of Resin B1)

23 parts of 1, 4- dioxanes were thrown into the four neck flask equipped with the thermometer and the reflux tube, and bubbling was performed for 30 minutes by nitrogen gas. 6.2 parts of monomer A, 12.97 parts of monomer B, 19.17 parts of monomer C (monomer ratio; monomer A: monomer B: monomer C = 25: 25: 50) under a nitrogen gas atmosphere, 2,2'-azobisisobutyronitrile 0.21 The solution which mixed 0.97 part of 2,2'- azobis (2, 4- dimethylvaleronitrile) and 34.51 parts of 1, 4- dioxanes was dripped at 75 degreeC over 1 hour. The resulting mixture was kept at 75 ° C. for 5 hours. The reaction mixture was cooled down and diluted with 42.18 parts of 1,4-dioxane. The obtained solution was poured into a mixture of 349 parts of methanol and 224 parts of ion-exchanged water with stirring, and the precipitated resin was collected by filtration, and the filtrate was washed three times with a mixture of 224 parts of methanol and 25 parts of ion-exchanged water. The obtained resin was dried under reduced pressure to obtain 23.1 parts of resin B1. Yield: 60%, Mw: 8,530, Mw / Mn: 1.74.

The resin has the following structural unit.

<Acid generator>

Acid Generator P1:

<Quenching agent>

Quenching agent Q1: 2,6-diisopropylaniline

<Solvent>

Solvent S1: 100.0 parts of propylene glycol monomethyl ether acetate

Propylene glycol monomethyl ether 20.0 parts

2-heptanone35.0 parts

γ-butyrolactone 3.5 parts

Examples 1 to 7, Comparative Example 1 and Reference Example 1

The following components were mixed to obtain a solution, and the solution was further filtered through a 0.2 μm fluorine resin filter to prepare a resist solution.

Resins (Types and amounts listed in Table 1)

Acid Generators (Types and Amounts are Listed in Table 1)

Quenching agents (types and amounts listed in Table 1)

Solvents (Types and amounts listed in Table 1)

The resist liquids prepared in Examples 1 to 7 were each represented by resists R1 to R7, the resist liquid prepared in Comparative Example 1 was represented by resist C1, and the resist liquid prepared in Reference Example 1 was represented by resist R10.

Each of the resist liquids prepared in Examples 1 to 3, Comparative Example 1 and Reference Example 1 was spin-coated to the antireflection film so that the film thickness after drying was 0.12 μm. After each resist liquid application, the silicon wafer coated with each resist liquid was prebaked at 100 ° C. for 60 seconds on a direct hot plate, respectively.

The contact angle and the retreat angle of each of the wafers were measured using "Drop Master-700" manufactured by Kyowa Kaimen Chemical Corporation. The contact angle was measured 0.1 seconds after dropping using 1 µl of water by the drop method, and the retreat angle was measured in the step gradient mode using 50 µl of water by the gradient method. Table 2 shows the results.

Each silicon wafer was coated with "ARC-95", an organic antireflective coating composition available from Nissan Chemical Industries, Limited, respectively, and baked at 205 DEG C under 60 seconds to produce an organic antireflective film having a thickness of 780 kPa. Formed. Each resist solution prepared in Examples 1 to 3, Comparative Example 1 and Reference Example 1 was spin-coated to the antireflection film so that the film thickness after drying was 0.12 μm. After each resist liquid application, the silicon wafer coated with each resist liquid was prebaked at 100 ° C. for 60 seconds on a direct hot plate, respectively. Using an ArF excimer stepper ("FPA5000-AS3" manufactured by Canon Inc., NA = 0.75), each wafer on which each resist film was formed was exposed in a line and a space pattern while gradually changing the exposure amount.

After exposure, each wafer was baked post-exposure at 110 ° C. for 60 seconds on a direct hot plate, followed by paddle development with an aqueous 2.38 wt% tetramethylammonium hydroxide solution.

Each pattern developed on the organic antireflective coating base after development was observed with a scanning electron microscope, and the results are shown in Table 3.

Line Width Roughness (LWR): The size of each pattern developed on the organic antireflective coating gas after development was observed with a scanning electron microscope. When the variation in size is smaller than Comparative Example 1, the evaluation is represented by "○", and when the variation in size is the same as Comparative Example 1, the evaluation is represented by "Δ", and the variation in size is larger than Comparative Example 1 , The evaluation was marked with "X".

The resist composition of the present invention is excellent in solubility in developer and excellent in resist pattern of LWR, which is suitable for optical lithography such as ArF excimer laser lithography. The resist film having a high retreat angle can be formed on the substrate by using the resist composition of the present invention to suppress defect formation in the immersion lithography method, and the composition of the present invention is particularly suitable for the immersion lithography method.

Claims (13)

A resin (A) containing a structural unit (a1) having an acid labile group on its side chain and not containing a fluorine atom, Not only contains one or more selected from the group consisting of a structural unit (b1) having an acid labile group in the side chain, a structural unit (b3) having a hydroxyl group in the side chain and a structural unit (b4) having a lactone structure in the side chain, Resin (B) containing a structural unit (b2) having a fluorine-containing group in the side chain, and Contains acid generators, The chemically amplified positive resist composition whose ratio which the said resin (B) occupies is 2 weight part or less with respect to 100 weight part of said resin (A). The chemically amplified positive resist composition according to claim 1, wherein the proportion of the resin (B) is 0.005 parts by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the resin (A). The chemistry according to claim 1, wherein the resin (A) contains at least one structural unit selected from the group consisting of a structural unit (a3) having a hydroxyl group and a structural unit (a4) having a lactone structure in addition to the structural unit (a1). Amplified Positive Resist Composition. The chemically amplified positive resist composition according to claim 3, wherein the resin (A) contains a structural unit (a3) and a structural unit (a4) in addition to the structural unit (a1). The chemically amplified positive resist composition according to claim 1, wherein the resin (B) contains a structural unit (b1) in addition to the structural unit (b2). The chemically amplified positive resist composition according to claim 1, wherein the structural units (a1) and (b1) independently represent structural units represented by formula (Ia) or structural units represented by formula (Ib).

(Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents a C1-C8 alkyl group, R ³ represents a methyl group, n represents an integer of 0 to 14, Z ¹ represents a single bond or-(CH ₂ ) represents a _k- COO- group, where k represents an integer from 1 to 4)

(Wherein R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a C1-C8 alkyl group, and R ⁶ , R ⁷ each independently represent a hydrogen atom or a monovalent C1- which may include one or more heteroatoms). represents a group C8 hydrocarbon or, R ⁶ and R ⁷ are combined with each other to R ⁶ form a ring with the carbon atom and R ⁷ carbon atoms, which is coupled to coupling or, R ^6, which combines the binding carbon atoms and R ^7, which The carbon atom may form a double bond, m represents an integer of 1 to 3, Z ² represents a single bond or a-(CH ₂ ) _{k '} -COO- group, where k' represents an integer of 1 to 4 ) The chemically amplified positive resist composition according to claim 1, wherein the structural unit (b3) represents a structural unit represented by the formula (IIb).

(In formula, R <^8> represents a hydrogen atom or a methyl group, R <^9> , R <^10> represents a hydrogen atom, a methyl group, or a hydroxyl group each independently, R <^11> represents a methyl group, n 'represents the integer of 0-12. , Z ³ represents a single bond or a-(CH ₂ ) _q -COO- group, where q represents an integer from 1 to 4) The chemically amplified positive resist composition according to claim 3, wherein the structural unit (b3) represents a structural unit represented by the formula (IIa).

(In formula, R <^12> represents a hydrogen atom or a methyl group, R <^13> , R <^14> represents a hydrogen atom, a methyl group, or a hydroxyl group each independently, R <^15> represents a methyl group, n "represents the integer of 0-12, Z ⁴ represents a single bond or a-(CH ₂ ) _{q '} -COO- group, where q' represents an integer from 1 to 4) The chemically amplified positive resist composition according to claim 1, wherein the structural unit (b4) represents a structural unit represented by formula IIIa, formula IIIb, formula IIIc, formula IIId, formula IIIe or formula IIIf.

(In formula, R <^17> represents a hydrogen atom or a methyl group, R <^18> represents a methyl group, R <^19> represents a carboxyl group, a cyano group, or C1-C4 hydrocarbon group each independently, R <^20> respectively independently represents a carboxyl group and a cyano group Or a C1-C4 hydrocarbon group, j represents an integer of 0 to 3, a represents an integer of 0 to 5, b represents an integer of 0 to 3, and c represents an integer of 0 to (2j + 2). Z ⁵ represents a single bond or a-(CH ₂ ) _{q "} -COO- group, where q" represents an integer of 1 to 4) The chemically amplified positive resist composition according to claim 3, wherein the structural unit (a4) represents a structural unit represented by formula IIIg, formula IIIh, formula IIIi, formula IIIj, formula IIIk or formula IIIl.

(In formula, R <^21> represents a hydrogen atom or a methyl group, R <^22> represents a methyl group, R <^23> represents a carboxyl group, a cyano group, or C1-C4 hydrocarbon group each independently, R <^24> respectively independently represents a carboxyl group and a cyano group Or a C1-C4 hydrocarbon group, i represents an integer of 0 to 3, d represents an integer of 0 to 5, e represents an integer of 0 to 3, f is an integer of 0 to (2i + 2) Z ⁶ represents a single bond or a-(CH ₂ ) _{q "'} -COO- group wherein q"' represents an integer of 1 to 4) The chemically amplified positive resist composition according to claim 1, wherein the structural unit (b2) represents a structural unit represented by the formula (IV).

(Wherein R ²⁵ represents a hydrogen atom or a methyl group, AR may contain 1 to 5 hydroxyl groups, and may comprise one or more heteroatoms selected from the group consisting of oxygen atoms, nitrogen atoms, sulfur atoms) C1-C30 fluorine-containing alkyl group) The chemically amplified positive resist composition according to claim 1, wherein the acid generator is a salt represented by the formula (V).

Wherein R ²⁶ represents a straight or branched hydrocarbon group of C 1 -C 6, or a monocyclic or bicyclic hydrocarbon group of C 3 -C 30, and at least one hydrogen atom in the monocyclic or bicyclic hydrocarbon group is C 1 -C 6 Alkoxy group, C1-C4 perfluoroalkyl group, C1-C6 hydroxyalkyl group, hydroxyl group, cyano group, carbonyl group and ester group, or at least one -CH ₂ -in the monocyclic or bicyclic hydrocarbon group May be substituted with -CO- or -O-, A ⁺ represents an organic counter ion, and Y ¹ , Y ² each independently represent a fluorine atom or a C 1 -C 6 perfluoroalkyl group) 13. The method of claim 12 wherein, R ²⁶ is a C3-C30 part formula or polycyclic hydrocarbon group having a hydroxyl group or a carbonyl group, wherein the part formula or polycyclic hydrocarbon groups at least one hydrogen atom of a C1-C6 alkyl group, C1-C6 alkoxy group And a chemically amplified positive resist composition which may be substituted with a C1-C4 perfluoroalkyl group, a C1-C6 hydroxyalkyl group, a hydroxyl group or a cyano group.