KR101996088B1 - Photoresist composition, process for forming resist pattern and acid generator - Google Patents

Abstract

An object of the present invention is to provide a photoresist composition capable of suppressing the occurrence of development defects. The present invention also relates to a photoresist composition containing an acid generator comprising a polymer having a structural unit (I) comprising an acid dissociable group [A] and a compound represented by the following formula (1). In the formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. The aliphatic heterocyclic ring may be conjugated to the carbon ring of the alicyclic hydrocarbon group. X is ** - (X ² -R ') _n -X ¹ -. X ¹ is * -COO- or -O-. X ² is -COO- or -O-. R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. The aliphatic heterocyclic ring may be conjugated to the carbon ring of the alicyclic hydrocarbon group. n is 0 or 1; R ² is a divalent straight-chain hydrocarbon group having an even number of carbon atoms or a divalent straight-chain fluorinated hydrocarbon group having an even number of carbon atoms. R ³ is a hydrogen atom or a fluorine atom.

Description

TECHNICAL FIELD [0001] The present invention relates to a photoresist composition, a resist pattern forming method, and an acid generator,

The present invention relates to a photoresist composition, a resist pattern forming method, and an acid generator.

The chemically amplified type photoresist composition is a photoresist composition in which an acid is generated in an exposed portion by irradiation with deep ultraviolet rays or electron rays represented by KrF excimer laser light or ArF excimer laser light, And a difference in dissolution rate with respect to the developing solution with the unexposed portion, thereby forming a resist pattern on the substrate.

Such a photoresist composition is not only excellent in resolution performance but also has various properties required such as smoothness of the formed resist pattern. Therefore, various acid generators have been proposed to control the intensity of the acid generated, the diffusion length and distribution in the resist film, and the like (see Patent Documents 1 to 5).

However, in order to further miniaturize the pattern, a demand for suppressing the occurrence of development defects in the formed resist pattern is increasing today, but the above conventional photoresist composition does not sufficiently satisfy this requirement.

Japanese Patent Application Laid-Open No. 2004-002252 Japanese Patent Application Laid-Open No. 2005-266766 U.S. Patent Application Publication No. 2006/0276670 Japanese Patent Application Laid-Open No. 2007-145803 Japanese Patent Application Laid-Open No. 2008-094835

The present invention has been made on the basis of the above-described circumstances, and its object is to provide a photoresist composition capable of suppressing the occurrence of development defects.

In order to solve the above problems,

(A) a polymer having a structural unit (I) containing an acid dissociable group (hereinafter also referred to as "[A] polymer"), and

[B] A photoresist composition containing an acid generator containing a compound represented by the following formula (1) (hereinafter also referred to as "[B] acid generator").

(In the formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that part or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the aliphatic hydrocarbon group may be an aliphatic heterocyclic ring is chukhwan the recall, X is ^{** - (X 2 -R ')} n -X 1 - and, X ¹ - is a -COO- or -O-, X ² is -COO- Or -O-, and R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the carbon-carbon double bond of the alicyclic hydrocarbon group and a may be an aliphatic heterocyclic ring is chukhwan, n is 0 or 1, and ** represents a site bonded to the R ^1, * represents the site binding to the R ¹ side, R ² is 2 of the number of carbon atoms is even Or a divalent straight-chain fluorinated hydrocarbon group having an even number of carbon atoms, and R ³ is hydrogen An atom or a fluorine atom, and M ⁺ is a monovalent cation)

The photoresist composition of the present invention can contain the [B] acid generator having the specific structure together with the [A] polymer to suppress the occurrence of development defects. The reason why the acid generator [B] has such a specific structure as described above can suppress the occurrence of development defects is not necessarily clarified. For example, the acid generator [B] may include R ¹ -X and SO ₃ ^- The affinity with the polymer [A] for forming a resist film is increased because of the structure having an odd number of carbon atoms. As a result, it is considered that the dispersibility of the [B] acid generator in the resist film is improved And the like.

The compound represented by the formula (1) is preferably represented by the following formula (1-1).

(Wherein R ¹ , X and M ⁺ are as defined in the above formula (1), and R ^A is a methylene group or a 1,3-propanediyl group)

According to the photoresist composition, the acid generator [B] having the specific structure described above exhibits, for example, a synergistic effect of the high dispersibility of the acid generator [B] and the appropriate strength of the generated acid, The generation of defects is further suppressed.

M ⁺ in the formula (1) is at least one kind of cation selected from the group consisting of a sulfonium cation represented by the following formula (2-1) and an iodonium cation represented by the following formula (2-2) .

(In the formula (2-1), R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group and the aryl group Or any two or more of R ⁴ , R ⁵ and R ⁶ may be bonded to each other to form a ring structure together with the sulfur atom to which they are bonded,

In the formula (2-2), R ⁷ and R ⁸ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, and some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted And R < ⁷ > and R < ⁸ > may be bonded to each other to form a ring structure together with the iodine atom to which they are bonded)

In the photoresist composition, the sensitivity of the [B] acid generator is improved by having the specific cation, and as a result, occurrence of development defects can be further suppressed.

The structural unit (I) is preferably represented by the following formula (3).

(3), R ⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R ¹⁰ , R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 10 carbon atoms or a monovalent An alicyclic hydrocarbon group wherein R ¹¹ and R ¹² may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded)

According to the photoresist composition, it is considered that the dispersibility of the acid generator [B] in the resist film can be further improved by using the structural unit (I) of the polymer [A] as the specific structural unit, The occurrence of defects can be further suppressed.

In the resist pattern forming method of the present invention,

(1) a step of forming a resist film on a substrate using the photoresist composition,

(2) exposing the resist film through a photomask, and

(3) a step of developing the exposed resist film

Respectively.

According to the method for forming a resist pattern, since the above-mentioned photoresist composition is used, a resist pattern with few development defects can be formed.

The acid generator of the present invention can be used,

Include compounds represented by the following formula (1).

(In the formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that part or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the aliphatic hydrocarbon group may be an aliphatic heterocyclic ring is chukhwan the recall, X is ^{** - (X 2 -R ')} n -X 1 - and, X ¹ - is a -COO- or -O-, X ² is -COO- Or -O-, and R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the carbon-carbon double bond of the alicyclic hydrocarbon group and a may be an aliphatic heterocyclic ring is chukhwan, n is 0 or 1, and ** represents a site bonded to the R ^1, * represents the site binding to the R ¹ side, R ² is 2 of the number of carbon atoms is even Or a divalent straight-chain fluorinated hydrocarbon group having an even number of carbon atoms, and R ³ is hydrogen An atom or a fluorine atom, and M ⁺ is a monovalent cation)

Since the acid generator has the specific structure described above, it can be preferably used as a component of the photoresist composition, and a photoresist composition capable of suppressing occurrence of development defects as described above can be obtained.

Here, the term "linear" means that the hydrocarbon group and the fluorinated hydrocarbon group have no branching structure and have a bond to carbon atoms at both ends of the group.

As described above, according to the photoresist composition and the method of forming a resist pattern of the present invention, a resist pattern with few development defects can be formed. Therefore, the photoresist composition, the resist pattern forming method and the acid generator of the present invention can be preferably used for forming a finer resist pattern.

≪ Photoresist composition >

The photoresist composition of the present invention contains the [A] polymer and the [B] acid generator. In addition, the photoresist composition may contain an optional component as long as the effect of the present invention is not impaired. Each component will be described below.

<[A] Polymer>

The [A] polymer is a polymer having a structural unit (I) containing an acid dissociable group. The photoresist composition contains the polymer [A] to dissociate the acid dissociable group by the action of an acid generated from the acid generator [B], thereby changing the solubility of the polymer in the developer, thereby forming a resist pattern can do. Further, according to the photoresist composition, it is considered that the [B] acid generator can be appropriately dispersed in the resist film to be formed by containing the [A] polymer, and a good resist pattern can be formed.

The polymer [A] preferably has a structural unit (II) comprising at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure in addition to the structural unit (I) (III) or the like.

[Structural unit (I)]

The structural unit (I) is a structural unit containing an acid dissociable group. The term "acid dissociable group" refers to a group capable of substituting a hydrogen atom of a polar group such as a carboxyl group or a hydroxyl group, and is a group dissociated by the action of an acid generated from the [B] acid generator or the like.

The structural unit (I) is preferably a structural unit represented by the above formula (3) (hereinafter also referred to as "structural unit (I-1)"). It is considered that the polymer [A] having the structural unit (I-1) as the structural unit (I) can improve the dispersibility of, for example, the [B] acid generator in the resist film, The occurrence of development defects in the photoresist composition can be further suppressed.

In the above formula (3), R ⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁰ , R ¹¹ and R ¹² are each independently an alkyl group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Provided that R &lt; ¹¹ &gt; and R &lt; ¹² &gt; may bond to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded.

As the R ⁹ , a methyl group is preferable in view of the copolymerization of the monomer providing the structural unit (I-1).

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ¹⁰ , R ¹¹ and R ¹² include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, Butyl group, t-butyl group and the like. Of these, a methyl group, an ethyl group and an i-propyl group are preferable, and a methyl group and an i-propyl group are more preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ¹⁰ , R ¹¹ and R ¹² include monovalent alicyclic hydrocarbon groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. An alicyclic hydrocarbon group; Norbornyl group, adamantyl group, tricyclodecanyl group, and tetracyclododecanyl group, and the like. Among them, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group are preferable, and a cyclopentyl group and an adamantyl group are more preferable.

Examples of the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms which R &lt; ¹¹ &gt; and R &lt; ¹² &gt; are bonded to each other with a carbon atom to which they are bonded include a cyclobutane diyl group, a cyclopentanediyl group, A monocyclic alicyclic hydrocarbon group such as a cyclohexanediyl group, a cyclohexanediyl group, or a cycloheptanediyl group; A norbornanediyl group, an adamantanediyl group and the like, and the like. Of these, a cyclopentanediyl group, a cyclohexanediyl group, a norbornanediyl group, and an adamantanediyl group are preferable, and a cyclopentanediyl group and an adamantanediyl group are preferable from the viewpoint of further enhancing the development defect suppressing property of the photoresist composition. More preferred is a cyclopentanediyl group.

Examples of the structural unit (I-1) include structural units represented by the following formulas (3-1) to (3-4).

In the formulas (3-1) to (3-4), R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are as defined in the above formula (3). n _p is an integer of 1 to 4;

Examples of the structural unit represented by the above formula (3) or (3-1) to (3-4) include structural units represented by the following formulas.

Wherein R ⁹ is as defined in the above formula (3).

Among these, the structural unit represented by the formula (3-1) and the structural unit represented by the formula (3-2) are preferable from the viewpoint of further enhancing the development defect suppressing property of the photoresist composition, (Meth) acrylate is more preferable, and a structural unit derived from 1-methyl-cyclopentyl (meth) acrylate, a structural unit derived from 1-i-propyl-cyclopentyl Is more preferable.

The content of the structural unit (I) is preferably from 20 mol% to 80 mol%, more preferably from 30 mol% to 70 mol%, still preferably from 35 mol% to 55 mol%, based on the total structural units constituting the polymer [A] Mol% is more preferable. If the content ratio of the structural unit (I) is less than the above lower limit, the pattern formability of the photoresist composition may be lowered. Conversely, if the content ratio of the structural unit (I) exceeds the upper limit, the adhesion of the formed resist pattern may be deteriorated.

[Structural unit (II)]

The structural unit (II) is a structural unit containing at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure. By having the polymer [A] having the structural unit (II), basic properties of the resist such as adhesiveness to the resist film formed with the photoresist composition can be further improved. Further, the resist film can be made more soluble in a developing solution. The lactone structure, the cyclic carbonate structure and the sultone structure are each a lactone ring (one ring containing a bond represented by -OC (O) -), a cyclic carbonate ring (-OC (O) -O- (One ring containing a bond represented by -OS (O) ₂ -) and a ring containing a bond represented by -OS (O) ₂ -.

Examples of the structural unit having a lactone structure include structural units represented by the following formulas.

In the formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the R ^L1 , a methyl group is preferable in view of the copolymerization of the monomer providing the structural unit (II).

As the structural unit (II) containing a lactone structure, a structural unit containing a norbornane lactone group is preferable, and a structural unit derived from norbornane lactonyl (meth) acrylate, a structural unit derived from norbornane lactonyloxycar Structural units derived from boronylmethyl (meth) acrylate are more preferred.

Examples of the structural unit having a cyclic carbonate structure include structural units represented by the following formulas.

In the formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The structural unit (II) containing a cyclic carbonate structure is preferably a structural unit having an ethylene carbonate ring, more preferably a structural unit derived from 1,2-propylene carbonate (meth) acrylate Do.

Examples of the structural unit (II) containing the sultone structure include structural units represented by the following formulas.

In the formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The content of the structural unit (II) is preferably 30% by mole to 80% by mole, more preferably 40% by mole to 70% by mole, and still more preferably 45% by mole to all structural units constituting the polymer [A] More preferably 65 mol%. When the content ratio of the structural unit (II) is within the above range, the adhesion of the resist film formed of the photoresist composition is further improved.

[Other structural units]

The polymer [A] may have other structural units other than the structural units (I) and (II). Examples of the other structural unit include a structural unit having a polar group. Examples of the structural unit having such a polar group include structural units represented by the following formulas.

In the formula, R ¹³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁴ is a hydrogen atom or a methyl group.

The content of the other structural units is generally 30 mol% or less, preferably 20 mol% or less, based on the total structural units constituting the polymer [A]. If the content ratio of the other structural units exceeds the upper limit, the pattern forming property of the photoresist composition may be deteriorated.

The content of the polymer [A] is usually 70 mass% or more, preferably 80 mass% or more, and more preferably 85 mass% or more, based on the total solid content of the photoresist composition.

<Method of synthesizing [A] polymer>

The polymer [A] can be synthesized, for example, by polymerizing a monomer providing each structural unit in a suitable solvent using a radical polymerization initiator.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis Azo type radical initiators such as 2,2'-azobis (2,4-dimethylvaleronitrile) and dimethyl 2,2'-azobisisobutylate; Peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and the like. Of these, AIBN and dimethyl 2,2'-azobisisobutylate are preferable, and AIBN is more preferable. These radical initiators may be used alone or in combination of two or more.

As the solvent used in the polymerization, for example,

alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane and n-decane;

Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin and norbornane;

Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene;

Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide and chlorobenzene;

Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;

Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone and 2-heptanone;

Ethers such as tetrahydrofuran, dimethoxy ethane and diethoxy ethane;

And alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. The solvents used in these polymerization may be used alone or in combination of two or more.

The reaction temperature in the above-mentioned polymerization is usually 40 ° C to 150 ° C and 50 ° C to 120 ° C. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

The weight average molecular weight (Mw) of the polymer [A] in terms of polystyrene determined by gel permeation chromatography (GPC) is not particularly limited, but is preferably 1,000 or more and 50,000 or less, more preferably 2,000 or more and 30,000 or less, More preferable. If the Mw of the polymer [A] is less than the lower limit described above, the heat resistance of the obtained resist film may be lowered. On the other hand, when the Mw of the [A] polymer exceeds 50,000, there is a fear that the developability of the resist film is lowered.

The ratio (Mw / Mn) of the polymer [A] to the number average molecular weight (Mn) converted to polystyrene by the GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less .

Herein, Mw and Mn of the polymer are values measured by gel permeation chromatography (GPC) under the following conditions.

GPC column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (manufactured by Toso Co., Ltd.)

Column temperature: 40 DEG C

Elution solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.)

Flow rate: 1.0 mL / min

Sample concentration: 1.0 mass%

Sample injection amount: 100 μL

Detector: differential refractometer

Standard material: monodisperse polystyrene

<[B] acid generator>

[B] The acid generator is an acid generator containing the compound represented by the above formula (1). The photoresist composition contains the [B] acid generator as the acid generator together with the polymer [A], so that occurrence of development defects can be suppressed.

In the above formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. However, some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted. In addition, aliphatic heterocyclic rings may be bonded to the carbon ring of the alicyclic hydrocarbon group. X is ** - (X ² -R ') _n -X ¹ -. X ¹ is * -COO- or -O-. X ² is -COO- or -O-. R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. However, some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted. In addition, aliphatic heterocyclic rings may be bonded to the carbon ring of the alicyclic hydrocarbon group. n is 0 or 1; ** represents a moiety bonded to R &lt; ^{1 &} gt ;. * Represents a site bonded to the R ¹ side. R ² is a divalent straight-chain hydrocarbon group having an even number of carbon atoms or a divalent straight-chain fluorinated hydrocarbon group having an even number of carbon atoms. R ³ is a hydrogen atom or a fluorine atom. M ⁺ is a monovalent cation.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ¹ include monocyclic alicyclic hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopropyl group and cyclohexyl group; A norbornyl group, an adamantyl group, a tricyclodecyl group, and a tetracyclododecyl group; and the like. Of these, a polycyclic alicyclic hydrocarbon group is preferable and an adamantyl group is more preferable from the viewpoint of further enhancing the development defect suppressing property of the photoresist composition.

Examples of the substituent that the alicyclic hydrocarbon group may have include a hydroxy group, a cyano group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, and an acyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonyl group.

Examples of the alkoxycarbonyloxy group include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, and a propoxycarbonyloxy group.

Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of the acyloxy group include an acetoxy group, a propionyloxy group, and a butyryloxy group.

Among the substituents which these alicyclic hydrocarbon groups may have, a hydroxyl group is preferred from the viewpoint that the polarity of the acid generated from the [B] acid generator is increased, and the acid diffusion length is suitably shortened.

Examples of the aliphatic heterocycle which may be routed to the carbon ring of the alicyclic hydrocarbon group include, for example,

Cyclic ether ring represented by the following formulas (a-1) to (a-4) and the like;

Cyclic amines represented by the following formulas (b-1) and (b-2);

Cyclic sulfide rings represented by the following formulas (c-1) to (c-4) and the like;

Cyclic ketone rings represented by the following formulas (d-1) to (d-3) and the like;

A lactone ring represented by the following formulas (e-1) to (e-4) and the like;

A lactam ring represented by the following formulas (f-1) to (f-4) and the like;

A cyclic carbonate ring represented by the following formulas (g-1) to (g-3) and the like;

A cyclic carbamate ring represented by the following formulas (h-1) to (h-3) and the like;

A cyclic urea ring represented by the following formulas (i-1) to (i-3) and the like;

A cyclic sulfone ring represented by the following formulas (j-1) to (j-3) and the like;

(K-1) to (k-3) shown below. The aliphatic heterocycle may be co-circulated by sharing one carbon-carbon bond with the carbon ring of the alicyclic hydrocarbon group, or it may be coordinated by sharing two or more carbon-carbon bonds.

Among them, the aliphatic heterocycle which may be coordinated with the carbon ring of the alicyclic hydrocarbon group is preferably a lactone ring, a cyclic carbonate ring, a cyclic carbonate ring, a cyclic carbonate ring or a cyclic carbonate ring from the viewpoint that the diffusion length of the acid generated from the [B] More preferably a lactone ring, more preferably a lactone ring represented by the above formula (e-2) and a lactone ring represented by the above formula (e-3), more preferably a norbornyl group A lactone ring represented by the formula (e-2), and a lactone ring represented by the above formula (e-3) which is cyclopentylated with a cyclopentyl group are particularly preferable.

X is ** - (X ² -R ') _n -X ¹ -. ** represents a moiety bonded to R &lt; ^{1 &} gt ;. n is 0 or 1; That is, X is ** - X ¹ - or ** - X ² -R'-X ¹ -. Examples of the divalent alicyclic hydrocarbon group represented by R 'include groups in which one hydrogen atom has been removed from those exemplified as the monovalent alicyclic hydrocarbon group represented by R ¹ . Examples of the substituent that the alicyclic hydrocarbon group may have include the same groups as exemplified as the substituent of the monovalent alicyclic hydrocarbon group represented by R ¹ . Examples of the aliphatic heterocycle which may be optionally fused to the carbon ring of the alicyclic hydrocarbon group include aliphatic heterocyclic rings exemplified as aliphatic heterocyclic rings which may be fused to the carbon ring of the monovalent alicyclic hydrocarbon group represented by R ¹ And the like. R 'is preferably a cycloalkanediyl group, more preferably a cycloalkanediyl group having from 3 to 8 carbon atoms, and still more preferably a cyclohexanediyl group. X ¹ and X ² are preferably -COO- in view of ease of synthesis of the [B] acid generator. n is preferably zero.

The number of carbon atoms of R ² is preferably an even number of 14 or less, more preferably an even number of 10 or less, still more preferably 2, 4, or 6, and more preferably 2 And 4 are particularly preferable, and 4 is most preferable.

Examples of the bivalent straight chain hydrocarbon group represented by R ² in which the number of carbon atoms is an even number include 1,2-ethanediyl, 1,4-butanediyl, 1,6-hexanediyl, A diaryl group, a 1,10-decanediyl group, and the like. Of these, the 1,2-ethanediyl group is more preferable.

Examples of the bivalent straight-chain fluorinated hydrocarbon group represented by R ² which is an even number of carbon atoms include a 1-fluoro-1,2-ethanediyl group, a 1,1-difluoro-1,2-ethanediyl group , 1,1,2,2-tetrafluoro-1,2-ethanediyl group, 1-fluoro-1,4-butanediyl group, 1,1-difluoro-1,4- 1,1-difluoro-1,6-hexanediyl group, and the like.

The R ³ is preferably a fluorine atom from the viewpoint that the strength of the acid generated from the [B] acid generator is appropriately increased.

Examples of the group represented by -R ² -CFR ³ - include 1-fluoro-1,3-propanediyl group, 1,1-difluoro-1,3-propanediyl group, -Trifluoro-1,3-propanediyl group, 1,1,2,2-tetrafluoro-1,3-propanediyl group, 1,1,2,2,3,3-hexafluoro-1 , 3-propanediyl group, 1-fluoro-1,5-pentanediyl group, 1,1-difluoro-1,5-pentanediyl group, 1,1,2-trifluoro- Pentanediyl group, 1,1,2,2-tetrafluoro-1,5-pentanediyl group, 1,1,2,2,3,3-hexafluoro-1,5-pentanediyl group, 1, Tetrafluoro-1,7-heptanediyl group, 1,1,2,2-tetrafluoro-1,9-nonanediyl group, 1,1,2,2-tetrafluoro- 1,11-undecandiyl group, and the like. Among these, from the viewpoint that the acid generated from the acid generator [B] is adequately strengthened, from the viewpoint that the development defect suppressing property of the photoresist composition is enhanced, 1,1,2,2-tetrafluoro-1,3- 1,1,2,2-tetrafluoro-1,5-pentanediyl group, 1,1,2,2-tetrafluoro-1,7-heptanediyl group, 1,1,2,2- Tetrafluoro-1,9-nonanediyl group is preferable.

As the compound represented by the above formula (1), for example, a synergistic effect of the high dispersibility of the acid generator [B] and the appropriate strength of the generated acid is exhibited, and as a result, From the viewpoint of inhibition, the compound represented by the above formula (1-1) is preferable.

In the above formula (1-1), R ¹ , X and M ⁺ are as defined in the above formula (1). R ^A is a methylene group or a 1,3-propanediyl group.

As R ^A , a 1,3-propanediyl group is preferable from the viewpoint of further reducing development defects of the resist pattern formed of the photoresist composition.

The monovalent cation represented by M &lt; ⁺ &^gt; is not particularly limited, but from the viewpoint of improving the sensitivity of the photoresist composition and consequently suppressing the occurrence of development defects, a monovalent cation represented by the following formula (2-1) It is preferably at least one cation selected from the group consisting of a sulfonium cation and a iodonium cation represented by the following formula (2-2).

In the formula (2-1), R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms. Some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted. Two or more of R ⁴ , R ⁵ and R ⁶ may be bonded to each other to form a ring structure together with the sulfur atom to which they are bonded.

In the formula (2-2), R ⁷ and R ⁸ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms. Some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted. R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure together with the iodine atom to which they are bonded.

Examples of the alkyl group having 1 to 20 carbon atoms represented by R ⁴ , R ⁵ and R ⁶ and R ⁷ and R ⁸ include methyl, ethyl, n-propyl, i-propyl, butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group and a n-decyl group.

Examples of the aryl group having 6 to 30 carbon atoms represented by R ⁴ , R ⁵ and R ⁶ and R ⁷ and R ⁸ include a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group and an anthranyl group. .

Examples of the substituent that the alkyl group and the aryl group may have include the same substituents as those of the alicyclic hydrocarbon group represented by R ¹ of the [B] acid generator.

The sulfonium cation is preferably a sulfonium cation represented by the following formula (2-1-1) and a sulfonium cation represented by the following formula (2-1-2).

In the formula (2-1-1), R ^a, R ^b and R ^c are each independently an alkyl group which may have a hydrogen atom, a hydroxy group, a halogen atom, a substituent, a cycloalkyl group, an alkoxy group, -SR group, or an ^α- SO ₂ -R ^{? Group} . Provided that R ^? Is an alkyl group or an aryl group which may have a substituent. R ^? Is an alkyl group, a cycloalkyl group, an alkoxy group or an aryl group which may have a substituent. n1, n2 and n3 are each independently an integer of 0 to 5;

In the formula (2-1-2), R ^d is a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 8 carbon atoms. However, some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted. In the case where R ^d is plural, a plurality of R ^d may be the same or different, have any two or more of the plurality of R ^d may be bonded to each other to form a ring structure. R ^e is a hydrogen atom, a linear or branched alkyl group having 1 to 7 carbon atoms, or an aryl group having 6 or 7 carbon atoms. However, some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted. In the case where R ^e is a plurality, the plurality of R ^e are the same or different, have any two or more of the plurality of R ^e may be bonded to each other to form a ring structure. n4 is an integer of 0 to 7; n5 is an integer of 0 to 6; n6 is an integer of 0 to 3;

Examples of the sulfonium cation include a cation represented by the following formulas (i-1) to (i-68).

Among them, the compound represented by the formula (i-1), the compound represented by the formula (i-2), the compound represented by the formula (i-6), the compound represented by the formula (i-8), the compound represented by the formula (i- (I-25), (i-27), (i-29), (i-33) ) And the sulfonium cation represented by the formula (i-57) are preferable, and the sulfonium cation represented by the formula (i-1) is more preferable.

As the iodonium cation, for example, a cation represented by the following formula (2-2-1) is preferable.

In the formula (2-2-1), R ^h and R ^g are each independently a hydrogen atom, a straight or branched alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. However, some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted. When each of R ^h and R ^g is plural, plural R ^h and R ^g may be the same or different, and two or more of plural R ^f and R ^g may combine with each other to form a ring structure . n7 and n8 are each independently an integer of 0 to 5;

Examples of the iodonium cation include iodonium cations represented by the following formulas (ii-1) to (ii-39).

Of these, iodonium cations represented by the above-mentioned formulas (ii-1) and (ii-11) are preferable, and iodonium cations represented by the above formula (ii-1) are more preferable.

Examples of the acid generator [B] include those represented by the following formulas (b-1) to (b-16).

In the above formulas (b-1) to (b-16), M ⁺ is synonymous with the above formula (1).

(B-1), (b-2), (b-5), (b-6) (b-1), (b-6), (b-9) and (b-16) And more preferred are the compounds represented by the above formulas (b-1), (b-6) and (b-16), respectively.

The content of the acid generator [B] is preferably from 0.1 part by mass to 30 parts by mass, more preferably from 0.2 part by mass to 20 parts by mass, further preferably from 0.5 part by mass to 15 parts by mass, per 100 parts by mass of the polymer [A] And particularly preferably 2 parts by mass to 15 parts by mass. If the content of the acid generator [B] is less than the above lower limit, the sensitivity of the photoresist composition may be insufficient. If the content of the acid generator [B] exceeds the upper limit, the pattern-forming property of the photoresist composition may be deteriorated.

&Lt; Synthesis method of [B] acid generator >

[B] The compound constituting the acid generator can be synthesized, for example, when n in the above formula (1) is 0 and X ¹ is -COO-, according to the following reaction formula.

In the above formulas, R ¹ , R ² , R ³ and M ⁺ are as defined in the above formula (1).

Sodium sulfonate is obtained by oxidizing a product obtained by reacting a bromo compound having a hydroxy group with sodium adititon, for example, in the presence of a catalyst such as sodium tungstate with hydrogen peroxide. By screen is a sulfonic acid sodium salt, and a sulfonic acid salt containing the M ⁺ as a cation from the salt comprises a monovalent cation represented by M ⁺ is obtained, and the sulfonic acid salt of a hydroxy group, using a carboxylic acid ester, the formula (1) can be obtained. In addition to the reaction sequence of the above reaction formula, the compound represented by the above formula (1) may be prepared by, for example, forming an ester compound from the carboxylic acid and a bromo compound having the hydroxy group, then adding sodium aditonate, Or may be synthesized by sulfo group formation by reacting with water. The compound in the case where n in the above formula (1) is 0 and X ¹ is -O- and the compound in which n in the above formula (1) is 1 can also be synthesized according to the above reaction formula .

<Optional ingredients>

[[C] Fluorine atom-containing polymer]

The [C] fluorine atom-containing polymer is a polymer having a higher fluorine atom content than the [A] polymer. Since the photoresist composition contains the fluorine atom-containing polymer [C], when the resist film is formed, the distribution thereof tends to be localized in the surface layer of the resist film due to the oil property of the fluorine atom-containing polymer [C] It is possible to suppress the elution of the acid generator and acid diffusion controller in the film into the immersion medium at the time of immersion exposure. Further, the forward contact angle between the resist film and the immersion medium can be controlled to a desired range by the water repellency characteristic of the [C] fluorine atom-containing polymer, and occurrence of bubble defects can be suppressed. Further, the contact angle of the resist film with the liquid immersion medium can be increased, and as a result, scan exposure can be performed at high speed without leaving water droplets. As such, the photoresist composition contains the [C] fluorine atom-containing polymer, so that a resist film preferable for a liquid immersion exposure method can be formed. The fluorine atom content (% by mass) of the polymer can be determined by identifying the structure of the polymer by ¹³ C-NMR measurement.

The [C] fluorine atom-containing polymer is not particularly limited as long as it is a fluorine atom-containing polymer, but it can be generally formed by polymerizing at least one monomer containing a fluorine atom in its structure. Examples of the monomer containing a fluorine atom in the structure include a fluorine atom in the main chain, a fluorine atom in the side chain, and a fluorine atom in the main chain and side chain.

Examples of the monomer containing a fluorine atom in the main chain include an? -Fluoroacrylate compound,? -Trifluoromethyl acrylate compound,? -Fluoroacrylate compound,? -Trifluoromethylacrylate compound, ?,? -fluoroacrylate compounds,?,? - trifluoromethylacrylate compounds, compounds in which at least one vinyl moiety has hydrogen substituted with a fluorine atom or a trifluoromethyl group, and the like.

Examples of the monomer containing a fluorine atom in the side chain include monomers in which the side chain of an alicyclic olefin compound such as norbornene is a fluorine atom or a fluoroalkyl group or its derivative, acrylic acid or methacrylic acid and a fluoroalkyl alcohol or a derivative thereof , A side chain (a site which does not contain a double bond) of at least one olefin is a fluorine atom, a fluoroalkyl group or an induction group thereof, and the like.

Examples of the monomer containing a fluorine atom in the main chain and side chain include, for example,? -Fluoroacrylic acid,? -Fluoroacrylic acid,?,? -Fluoroacrylic acid,? -Trifluoromethylacrylic acid,? -Trifluoromethyl Acrylic acid,?,? - ditrifluoromethyl acrylic acid and the like, an ester compound formed by a fluoroalkyl alcohol or a derivative thereof, a side chain of a compound in which hydrogen of at least one vinyl moiety is substituted with a fluorine atom or a trifluoromethyl group, A hydrogen atom bonded to a double bond of at least one alicyclic olefin compound is substituted with a fluorine atom or a trifluoromethyl group and the side chain is substituted with a fluoroalkyl group or a derivative thereof And the like. The alicyclic olefin compound means a compound in which a part of the ring is a double bond.

In the fluorine atom-containing polymer, the structural unit for imparting the fluorine atom is not particularly limited, but a structural unit represented by the following formula (C1) (hereinafter also referred to as "structural unit (CI)") Is preferably used as a unit.

In the above formula (C1), R ⁱ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. A is a single bond or a divalent linking group. R ¹⁵ is a linear or branched alkyl group having 1 to 6 carbon atoms and at least one fluorine atom, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

Examples of the divalent linking group represented by A include an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, an amide group, a sulfonylamide group, and a urethane group.

Preferred monomers for providing the structural unit (CI) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, (Meth) acrylic acid esters, perfluoro (meth) acrylic acid esters, perfluoro (meth) acrylic acid esters, perfluoro n-butyl (meth) acrylate ester, 1- (2,2,3,3,4,4,4-hexafluoropropyl) (meth) acrylate, 2- (Meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylate , 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-Trifluoromethyl-3,3,4,4,5,6, 6,6-octafluorohexyl) (meth) acrylate, and the like.

The proportion of the structural unit (CI) in the fluorine atom-containing polymer is usually 5 mol% or more, preferably 10 mol% or more, and more preferably 15 mol% or more based on the total structural units in the fluorine atom- Mol% or more. If the content of the structural unit (C-I) is less than 5 mol%, there is a possibility that a receding contact angle of 70 DEG or more can not be attained or elution of an acid generator or the like from the resist film can not be suppressed. The fluorine atom-containing polymer may contain only one structural unit (C-I), or may contain two or more kinds of structural units (C-I).

The fluorine atom-containing polymer may contain, in addition to the above-mentioned structural unit having a fluorine atom in its structure, for example, a structural unit having an acid dissociable group or a lactone skeleton, a hydroxyl group, a carboxyl group, etc. , Or a structural unit having an alicyclic compound or a "structural unit derived from an aromatic compound" in order to suppress light scattering due to reflection from the substrate.

Examples of the structural unit having a dissociable group include a structural unit represented by the following formula (C2) (hereinafter also referred to as a &quot; structural unit (C-II) &quot;).

In the formula (C2), R ^j is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^q1 , R ^q2 and R ^q3 are each independently a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or an inducing group thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^q1 , R ^q2 and R ^q3 include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclo A group derived from an alicyclic ring such as cycloalkanes such as pentane, cyclohexane, cycloheptane, and cyclooctane; A part or all of the hydrogen atoms of the groups derived from these alicyclic rings may be substituted with a substituent such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n- a linear or branched alkyl group having 1 to 4 carbon atoms such as a t-butyl group, or a cycloalkyl group having 3 to 10 carbon atoms such as a cyclobutyl group and a cyclohexyl group, or a group substituted with one or more of . Any two of R ^q1 to R ^q3 may combine with each other to form a bivalent alicyclic hydrocarbon group or an inducing group thereof together with the carbon atom to which they are bonded. Among these alicyclic hydrocarbon groups, a group derived from an alicyclic ring of norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, or a group derived from a cycloaliphatic ring, Is preferable.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ^q1 , R ^q2 and R ^q3 include methyl, ethyl, n-propyl, i-propyl, -Methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the group bonded to the oxygen atom of the acid dissociable group, that is, the ester group in the above formula (C2) include t-butyl group, 1-n- (1,1-dimethyl) propyl group, 1-n- (1,1-dimethyl) butyl group, 1- (1-ethyl) pentyl group, 1- (1-methyl) cyclopentyl group, 1- (1- (1-methylpropyl) cyclopentyl group, 1- (1-methyl) cyclohexyl group, 1- (1-ethyl) 1- (1-propyl) cyclohexyl group, 1- {1-methyl-1- (2-norbornyl}} ethyl group, 1- { (1-methyl-1- (1-adamantyl)} ethyl group, 2- (2-methyl) 2- (2-methylpropyl) norbornyl group, 2- (2-methyl) tetracyclodecanyl group, 2- -Ethyl) tetracyclodecanyl &lt; / RTI &gt; , 1- (1-methyl) adamantyl group, 1- (1-ethyl) adamantyl group, 2- , A 1- (1-propyl) adamantyl group, a 1- (1-i-propyl) adamantyl group and a group formed by these alicyclic ring groups such as methyl, ethyl, A linear or branched alkyl group having 1 to 4 carbon atoms such as an n-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group or a t-butyl group, Or a group substituted with at least one group.

Preferred monomers for providing the structural unit (C-II) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-methyl-3-hydroxyadamantyl- (Meth) acrylate, 2-ethyladamantyl-2-yl (meth) acrylate, 2-ethyl-3-hydroxyadamantyl- 2-yl ester, (meth) acrylic acid 2-isopropyladamantyl-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1] hept- (Meth) acrylate-8-methyltricyclo [5.2.1.0 ^2,6 ] decan-8-yl ester, (meth) acrylic acid-8- Ethyltricyclo [5.2.1.0 ^2,6 ] decan-8-yl ester, (meth) acrylic acid-4-methyltetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodecan-4-yl ester, Methacrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodecan-4-yl ester, (meth) (Meth) acrylic acid 1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -1- (Meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) -1-methyl ethyl ester, -1-methylethyl ester, (meth) acrylic acid 1- (3-hydroxyadamantan-1-yl) -1-methylethyl ester, 1,1-dicyclohexylethyl methacrylate Ester, (meth) acrylic acid 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, (meth) acrylate 1,1-di (tricyclo [5.2.1.0 ^2,6 ] decane- (Meth) acrylate, 1,1-di (tetracyclo [6.2.1 ^3,6 .0 ^2,7 ] dodecan-4-yl) ethyl ester of (meth) 1-cyclopentyl (meth) acrylate, 1-methyl-1-cyclopentyl (meth) acrylate, 1-methyl- - Cyclohexyl ester 1-ethyl-1-cyclohexyl (meth) acrylate, and the like.

Among these monomers, (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylate 2-ethyladamantyl- Hept-2-yl ester, (meth) acrylic acid 2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept- 1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl ester, 1-cyclohexyl (meth) acrylate, 1-methyl-1-cyclohexyl (meth) acrylate and 1-ethyl-1-cyclohexyl (meth) acrylate are preferable.

As the structural unit having a lactone skeleton, the same structural unit as the structural unit (II) of the polymer [A] (hereinafter also referred to as &quot; structural unit (C-III)

Examples of the structural unit having an alicyclic group include a structural unit represented by the following formula (C4) (hereinafter also referred to as "structural unit (C-IV)").

In the above formula (C4), R ^k is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁶ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ¹⁶ include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] Derived from cycloaliphatic rings of cycloalkanes such as cyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodecane, tricyclo [3.3.1.1 ^3,7 ] , And the like. The hydrocarbon group derived from an alicyclic ring derived from the cycloalkane may have a substituent, and examples thereof include a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, A linear or branched alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, propyl, or t-butyl, or a cycloalkyl group having 3 to 10 carbon atoms. The substituent is not limited to these alkyl groups and cycloalkyl groups but may be a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group, or an oxygen atom.

(Meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2.2] oct- Tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] dodeca-9- yl ester, (meth) acrylic acid-include tricyclo [3.3.1.1 ^3,7] deck-2-yl ester such as tricyclo [3.3.1.1 ^3,7] dec-l-yl ester, (meth) acrylic acid have.

Examples of preferred monomers for providing structural units derived from the aromatic compound (hereinafter also referred to as "structural unit (CV)") include styrene, α-methylstyrene, 2-methylstyrene, 3- Methoxystyrene, 4-methoxystyrene, 4- (2-t-butoxycarbonylethyloxy) styrene 2-hydroxystyrene, 3-methoxystyrene, 3- , 4-hydroxystyrene, 2-hydroxy-? -Methylstyrene, 3-hydroxy-? -Methylstyrene, 4-hydroxy-? -Methylstyrene, 2-methyl- Hydroxystyrene, 3-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene, 2,4-dihydroxystyrene, (2-ethyl-2-propoxy) styrene, 4-t-butoxystyrene, 4-t- butoxy- Propoxy) -? - methylstyrene, 4- (1-ethoxyethoxy) styrene, 4- (1-ethoxyethoxy) 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1- (meth) acrylate, (Meth) acrylate, 2-naphthyl (meth) acrylate, 1-naphthylmethyl (meth) acrylate, Anthryl (meth) acrylate, 9-anthrylmethyl (meth) acrylate, and 1-vinylpyrrene.

(C-II), the structural unit (C-III), the structural unit (C-IV) and the structural unit (CV) as the "other structural unit" of the [C] fluorine atom- Or two or more species. In the above-mentioned [C] fluorine atom-containing polymer, the content ratio of these other structural units is usually 80 mol% or less, preferably 75 mol% or less based on the total structural units constituting the [C] More preferably 70 mol% or less.

The content of the fluorine atom-containing polymer [C] is preferably from 0 to 20 parts by mass, more preferably from 0.5 parts by mass to 15 parts by mass, further preferably from 1 part by mass to 10 parts by mass, per 100 parts by mass of the polymer [A] . By setting the content of the fluorine atom-containing polymer [C] within the above-described range, the resist film can be preferably formed by liquid immersion lithography.

<Method of synthesizing fluorine atom-containing polymer> [C]

The [C] fluorine atom-containing polymer can be synthesized, for example, by polymerizing a monomer which provides a desired structural unit in the presence of a radical polymerization initiator in an appropriate solvent, like the polymer [A] described above.

[[D] acid diffusion control agent]

[D] acid diffusion control agent can control the diffusion phenomenon of an acid generated from [B] acid generator and the like in a resist film by exposure to exhibit an effect of suppressing an undesirable chemical reaction in a non-exposed region , The storage stability of the obtained photoresist composition is further improved and the resolution as a resist is further improved and the change in the line width of the resist pattern due to the variation of the post exposure delay time from exposure to development treatment can be suppressed, This very excellent composition is obtained.

Examples of the acid diffusion control agent [D] include an amine compound, an amide group-containing compound, a urea compound, and a nitrogen-containing heterocyclic compound.

Examples of the amine compound include mono (cyclo) alkyl amines; Di (cyclo) alkyl amines; Tri (cyclo) alkyl amines; Substituted alkyl anilines or derivatives thereof; N, N ', N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, Diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ether, bis N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine, 2-ethylhexylamine, , N, N, N ', N "N'" - pentamethyldiethylenetriamine, and the like.

Examples of the amide group-containing compound include Nt-butoxycarbonyl group-containing amino compounds such as Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine Amyloxycarbonyl group-containing amino compounds represented by the general formula (1), N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, Pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl), and the like. Among them, an amino compound containing an Nt-butoxycarbonyl group and an amino compound containing an Nt-amyloxycarbonyl group are preferable, and Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl- Cipiperidine is more preferable.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri- -Butylthiourea, and the like.

Examples of the nitrogen-containing heterocyclic compound include imidazoles; Pyridines; Piperazines; Piperidine, piperidine, piperazine, pyrazole, pyridazine, quinoxaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2. 2] octane.

As the acid diffusion control agent [D], a photodegradable base which generates a weak acid upon exposure by exposure may also be used. Examples of the photodegradable base include an onium salt compound which is decomposed by exposure and loses acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (D1) and an iodonium salt compound represented by the following formula (D2).

In the formulas (D1) and (D2), R ¹⁷ to R ²¹ each independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group or a halogen atom. Z ^- and E ^- are each independently OH ^- is an anion represented by the formula or ^{(D3) -, R H -COO-} , R H -SO 3. Provided that R ^H is an alkyl group, an aryl group or an aralkyl group.

In the above formula (D3), R ²² represents a linear or branched alkyl group having 1 to 12 carbon atoms, a part or all of the hydrogen atoms may be substituted with a fluorine atom, or a linear or branched alkoxyl group having 1 to 12 carbon atoms to be. u is an integer of 0 to 2;

As the photo-degradable base, those containing an anion represented by the above formula (D3) are preferable, and triphenylsulfonium salicylate is more preferable.

The content of [D] acid diffusion control agent in the photoresist composition is preferably less than 10 parts by mass, more preferably less than 8 parts by mass based on 100 parts by mass of the polymer [A]. When the content of [D] acid diffusion control agent exceeds 10 parts by mass, the sensitivity of the photoresist composition tends to decrease. The photoresist composition may contain one or more acid diffusion controlling agents [D].

[[E] Solvent]

The photoresist composition usually contains [E] solvent. The solvent [E] is not particularly limited as long as it can dissolve or disperse the [A] polymer, the [B] acid generator, and optional components as required.

Examples of the [E] solvent include an alcohol solvent, an ether solvent, a ketone organic solvent, an amide solvent, an ester organic solvent and a hydrocarbon solvent.

Examples of the alcoholic solvent include alcohols such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert- Butanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, Octanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl Monoalcohol solvents such as alcohol, sec-heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol and diacetone alcohol;

Propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4- Polyhydric alcohol solvents such as 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol and tripropylene glycol;

Ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol mono Methyl ethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene Glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monopropyl ether; and the like.

Examples of the ether solvent include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, methoxybenzene, anisole (methylphenyl ether) and the like.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl iso butyl ketone, methyl n-pentyl ketone N-butyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2 , 4-pentanedione, acetonyl acetone, and acetophenone.

Examples of the amide solvent include N, N'-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, Amide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like.

Examples of ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate,? -Butyrolactone,? -Valerolactone, n-propyl acetate, isopropyl acetate, acetic acid n Butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, , Benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene Glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether Propylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diacetic acid glycol, methoxytriglycol acetate, propyleneglycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, Ethyl lactate, n-butyl lactate, diethyl malonate, dimethyl phthalate, di-n-butyl lactate, di-n-butyl lactate, isopropyl myristate, n-butyl propionate, isoamyl propionate, diethyl oxalate, Ethyl and the like.

Examples of the hydrocarbon-based solvent include n-pentane, iso-pentane, n-hexane, isohexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, Aliphatic hydrocarbon solvents such as cyclohexane and methylcyclohexane;

Benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, isopropylbenzene, diethylbenzene, isobutylbenzene, triethylbenzene, di- And aromatic hydrocarbon solvents such as amylnaphthalene.

Among these, ester solvents and ketone solvents are preferable, and propylene glycol monomethyl ether acetate, cyclohexanone and? -Butyrolactone are more preferable. The photoresist composition may contain one or more [E] solvents.

[Other optional components]

The photoresist composition may contain, in addition to the above components [A] to [E], other optional components. Examples of other optional components include acid generators other than the acid generator [B], surfactants, and alicyclic skeleton-containing compounds. These other optional components may be used alone or in combination of two or more.

[Other acid generators]

The photoresist composition may contain an acid generator other than the above-mentioned [B] acid generator if the amount of the acid generator is such a small amount as not to impair the effect of the present invention. Examples of other acid generators include, for example, onium salt compounds other than the acid generator [B], sulfone compounds, sulfonate ester compounds, N-sulfonyloxyimide compounds, diazomethane compounds, disulfonylmethane compounds, oxysulfonate compounds , Hydrazinesulfonate compounds, and the like.

[Surfactants]

The surfactant has the effect of improving the coatability, striation, developability and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol di Nonionic surfactants such as laurate and polyethylene glycol distearate; Fifth EF301, EF303 and EF352 (manufactured by TOKEM PRODUCTS CORPORATION) were used as commercially available products, such as KP341 (Shinetsuga Kogyo Kogyo), Polyflow No. 75, No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.) (Manufactured by DIC), Fluorad FC430, FC431 (manufactured by Sumitomo 3M Limited), Asahi Guard AG710, Surplon S-382, Copper SC-101, Copper SC-102, Copper F171 SC-103, SC-104, SC-105 and SC-106 (manufactured by Asahi Glass Co., Ltd.). The content of the surfactant in the photoresist composition is usually 2 parts by mass or less based on 100 parts by mass of the polymer [A].

[Alicyclic skeleton-containing compound]

The alicyclic skeleton-containing compound exerts the effect of improving dry etching resistance, pattern shape, adhesion with a substrate, and the like.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl;

Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate and 2-ethoxyethyl deoxycholate;

Acid esters such as t-butyl dicarbonate, t-butyl dicarbonate, t-butyl dicarbonate, t-butyl dicarbonate, t-butoxycarbonyl methyl dicarbonate and 2-ethoxyethyl dicarbonate;

3-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl- 5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane and the like. The content of the alicyclic skeleton-containing compound in the photoresist composition is usually 5 parts by mass or less based on 100 parts by mass of the polymer [A].

[Increase / decrease]

The sensitizer exhibits an effect of increasing the amount of acid generated from the [B] acid generator and the like, and exhibits an effect of improving the &quot; apparent sensitivity &quot; of the photoresist composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, nonacetyls, eosin, rose bengals, pyrenes, anthracenes, phenothiazines and the like. These sensitizers may be used alone or in combination of two or more. The content of the sensitizer in the photoresist composition is usually 2 parts by mass or less based on 100 parts by mass of the polymer [A].

&Lt; Method for producing photoresist composition >

The photoresist composition can be produced, for example, by mixing the polymer [A], the acid generator [B], optional components optionally contained, and the [E] solvent in a predetermined ratio. The photoresist composition is preferably filtered, for example, with a filter having a pore size of about 0.2 mu m after mixing. The total solid concentration of the photoresist composition is generally 0.5% by mass to 50% by mass, preferably 1% by mass to 25% by mass.

<Method of Forming Resist Pattern>

In the resist pattern forming method of the present invention,

(1) a step of forming a resist film on a substrate using the photoresist composition,

(2) exposing the resist film through a photomask, and

(3) a step of developing the exposed resist film

Respectively.

According to the method for forming a resist pattern, since the above-mentioned photoresist composition is used, a resist pattern with few development defects can be formed. Hereinafter, each step will be described.

[(1) Process]

In the step (1), a resist film is formed by applying the photoresist composition on a substrate by appropriate application means such as spin coating, soft coating or roll coating. Examples of the substrate include silicon wafers, silicon dioxide, wafers coated with an antireflection film, and the like. Specifically, the photoresist is applied so that the obtained resist film has a predetermined film thickness, and then soft baking (SB) is performed to vaporize the solvent in the coated film to form a resist film. The temperature of the SB is usually 60 to 140 占 폚, preferably 80 to 120 占 폚. The time of SB is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[(2) Process]

In the step (2), the resist film formed in the step (1) is exposed to exposure light through a photomask (in some cases, through an immersion medium such as water). At this time, exposure light is irradiated through a mask having a predetermined pattern. The exposure light is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-ray, charged particle light, and the like depending on the line width of the intended pattern. Of these, far ultraviolet rays such as ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are preferable, and ArF excimer laser light is particularly preferable.

After the exposure, it is preferable to perform post exposure baking (PEB) to promote dissociation of the acid dissociable group in the polymer [A] by the acid generated by exposure in the exposed portion of the resist film. With this PEB, there is a difference in solubility in an exposed portion (exposed portion) and in an unexposed portion (unexposed portion) to an alkali developing solution. The temperature of the PEB is usually from 50 캜 to 180 캜, preferably from 80 캜 to 130 캜. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[(3) Process]

In step (3), the exposed resist film is developed with a developer to form a predetermined resist pattern. After development, it is common to clean with water or the like and dry. Examples of the developer include aqueous solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di- Ethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -Diazabicyclo- [4.3.0] -5-nonene, or the like is preferably dissolved in an aqueous alkali solution in which at least one kind of alkaline compound is dissolved. In addition, a solvent containing an organic solvent such as a hydrocarbon solvent, an ether solvent, an ester solvent, a ketone solvent, an alcohol solvent, or an organic solvent may be used as the developer.

In the case of liquid immersion lithography, a liquid immersion protective film insoluble in the immersion liquid may be provided on the resist film in order to protect direct contact between the immersion liquid and the resist film before the step (2). Examples of the immersion protective film include a solvent peelable type protective film which is peeled off by a solvent before the step (3) (see, for example, Japanese Patent Laid-Open No. 2006-227632), a developer peelable type protective film For example, WO2005-069076 and WO2006-035790) may be used. However, from the viewpoint of the work throughput, it is preferable to use a protective film for liquid immersion for developer.

<Acid Generator>

The acid generator of the present invention is an acid generator containing the compound represented by the above formula (1).

In the above formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. However, some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted. In addition, aliphatic heterocyclic rings may be bonded to the carbon ring of the alicyclic hydrocarbon group. X is ** - (X ² -R ') _n -X ¹ -. X ¹ is * -COO- or -O-. X ² is -COO- or -O-. R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. However, some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted. In addition, aliphatic heterocyclic rings may be bonded to the carbon ring of the alicyclic hydrocarbon group. n is 0 or 1; ** represents a moiety bonded to R &lt; ^{1 &} gt ;. * Represents a site bonded to the R ¹ side. R ² is a divalent straight-chain hydrocarbon group having an even number of carbon atoms or a divalent straight-chain fluorinated hydrocarbon group having an even number of carbon atoms. R ³ is a hydrogen atom or a fluorine atom. M ⁺ is a monovalent cation.

The acid generator is described as the acid generator [B] of the photoresist composition, and a description thereof is omitted here.

[Example]

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

[Mw and Mn]

Mw and Mn of the polymer were measured according to the method described above in the specification.

[ ¹ H-NMR analysis, ¹³ C-NMR analysis and ¹⁹ F-NMR analysis]

¹ H-NMR analysis, ¹³ C-NMR analysis and ¹⁹ F-NMR analysis were carried out using a nuclear magnetic resonance apparatus (Jnm-EX270, manufactured by Nihon Denshi Co., Ltd.).

<Synthesis of Compound>

[Example 1] (Synthesis of compound (B-1)

The following compound (B-1) was synthesized according to the following reaction formula.

(Synthesis of compound (b2)) [

A thermometer and a condenser were charged with 10.0 g of 5-bromo-4,4,5,5-tetrafluoropentan-1-ol (the above compound (b1)), 5.98 g of sodium hydrogencarbonate, 10.92 g of sodium aditioate g, 20 ml of acetonitrile and 15 ml of water, and the reaction was carried out at 64 占 폚 for 10 hours under a nitrogen atmosphere. ^The disappearance of the starting material was confirmed by ¹⁹ F-NMR, and the reaction was terminated. Thereafter, acetonitrile was distilled off under reduced pressure to obtain an aqueous solution of a crude product of the compound (b2) without further purification.

(Synthesis of compound (b3)) [

A total amount of the aqueous solution of the crude product of the obtained compound (b2) and a sodium bicarbonate hydrate of tungstic acid (IV) were charged in a flask made of glass having a thermometer and a condenser, and then 5.09 g of 35 mass% hydrogen peroxide solution was added dropwise. After stirring at room temperature for 5 hours, the disappearance of the starting material was confirmed by ¹⁹ F-NMR and the reaction was terminated. After completion of the reaction, further 20 ml of water was added, and the resulting aqueous layer was washed 5 times with 30 ml of dichloromethane to obtain an aqueous solution of the compound (b3).

(Synthesis of compound (b4)) [

The whole amount of the aqueous solution of the obtained compound (b3) and 18.82 g of triphenylsulfonium chloride were added to a flask equipped with a thermometer and a condenser, followed by stirring at room temperature for 6 hours. Thereafter, the reaction solution was extracted three times with 100 ml of dichloromethane, and the obtained organic layer was washed six times with 150 ml of water. Dichloromethane was distilled off from the obtained organic layer under reduced pressure to obtain 17.51 g of a compound (b4).

(Synthesis of compound (B-1)) [

In a flask equipped with a thermometer and a condenser, 5 g of the obtained compound (b4) and 4.29 g of 1-adamantanecarbonyl chloride were dissolved in a mixed solvent of 100 ml of methanol and 50 ml of dichloromethane. Thereafter, 3.27 g of triethylamine was added dropwise in an ice bath. After completion of the dropwise addition, the mixture was stirred at room temperature for 6 hours, and an aqueous solution of sodium hydrogencarbonate was added to complete the reaction. The resulting solution was washed once with an aqueous solution of sodium hydrogencarbonate and 10 times with water, and the dichloromethane solution was recovered. The dichloromethane was distilled off under reduced pressure to obtain 6.6 g of a compound (B-1) (yield 92%, purity 98% based on the compound (b1)).

[Example 2] (Synthesis of compound (B-2)

The following compound (B-2) was synthesized according to the following reaction formula.

(Synthesis of compound (b5)) [

4 g of the compound (b1), 287 mg of p-toluenesulfonic acid and 3.94 g of 3-hydroxy-1-adamantanecarboxylic acid were dissolved in 400 ml of toluene in a flask equipped with a thermometer and a condenser. The mixture was allowed to react at 120 DEG C for 12 hours, and then cooled to room temperature. The toluene was distilled off under reduced pressure, and then 100 ml of dichloromethane was added to dissolve the solution. The solution was washed once with aqueous sodium hydrogencarbonate solution and twice with water. Dichloromethane was distilled off from the obtained organic layer under reduced pressure to obtain 6.63 g of a compound (b5).

(Synthesis of compound (B-2)) [

(B-2) was obtained in the same manner as in the synthesis of the compound (B-1) from the compound (b2) of Example 1, using the obtained compound (b5) 81%, purity 92%).

[Example 3] (Synthesis of compound (B-3)

The procedure of Example 1 was repeated except that 3-bromo-2,2,3,3-tetrafluoropropan-1-ol was used instead of the compound (b1) to obtain the following compound (B -3) (yield 88% for compound (b1)).

<Synthesis of [A] Polymer and [C] Fluorine-Containing Polymer>

The monomers used for the synthesis of the [A] polymer and the [C] fluorine atom-containing polymer are shown below.

The compounds (M-1), (M-2), (M-3) and (M-6) (II), respectively.

<Synthesis of [A] Polymer>

[Synthesis Example 1] (Synthesis of polymer (A-1)

21.54 g (50 mol%) of the compound (M-1) and 28.46 g (50 mol%) of the compound (M-5) as a monomer were dissolved in 100 g of 2-butanone and 4.21 g of AIBN 5 mol% based on the total molar amount) was dissolved to prepare a monomer solution. A 500 ml three-necked flask charged with 50 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 캜 with stirring, and the monomer solution was added dropwise over 3 hours using a dropping funnel. The start of dropwise addition was defined as the polymerization initiation time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the polymerization reaction solution was cooled to 30 캜 or lower by water-cooling, and the resulting mixture was poured into a mixed solvent of 800 g of methanol and 200 g of water. The precipitated white powder was filtered off. The white powder obtained by filtration was dispersed in 200 g of methanol to prepare a slurry, followed by filtration, followed by filtration twice. Thereafter, the mixture was vacuum-dried at 50 DEG C for 17 hours to obtain a polymer (A-1) (37.5 g, yield 75%). The polymer (A-1) had an Mw of 5,100 and a Mw / Mn of 1.34. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (M-1): the structural unit derived from the compound (M-5) was 48:52 (mol%).

[Synthesis Examples 2 to 5] (Polymers (A-2) to (A-5)) [

Polymers (A-2) to (A-5) were obtained in the same manner as in Synthesis Example 1 except that monomers and the polymerization initiators of the kind and amount described in Table 1 were used. Table 1 also shows the content ratio, Mw, Mw / Mn ratio, and yield (%) of each structural unit of each polymer obtained.

<Synthesis of fluorine atom-containing polymer [C]

[Synthesis Example 4] (Synthesis of polymer (C-1)

37.41 g (40 mol%) of the compound (M-6) and 62.59 g (60 mol%) of the compound (M-7) were dissolved in 100 g of 2-butanone and 4.79 g (7 mol%) of AIBN was dissolved A monomer solution was prepared. A 1,000 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, purged with nitrogen and heated to 80 DEG C while stirring the reaction kettle. The monomer solution was introduced into the flask over 3 hours using a dropping funnel . The start of dropwise addition was defined as the polymerization initiation time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the polymerization reaction solution was water-cooled and cooled to 30 캜 or lower. The polymerization reaction solution was concentrated under reduced pressure to a mass of 150 g by an evaporator. Thereafter, the concentrate was poured into a mixture of 760 g of methanol and 40 g of water to precipitate a slurry-like white solid. The liquid portion was removed by decantation and the recovered solid was vacuum-dried at 50 캜 for 17 hours to obtain a polymer (C-1) as a white powder (47 g, yield 47%). The polymer (C-1) had an Mw of 3,700 and an Mw / Mn of 1.40. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (M-6) derived from the compound (M-7) was 42.5: 57.5 (mol%).

&Lt; Preparation of photoresist composition >

Components constituting the photoresist composition other than the [A] polymer and the [C] fluorine atom-containing polymer are shown below.

[Component [B]]

B-1: Triphenylsulfonium 1,1,2,2-tetrafluoro-5- (1-adamantanecarbonyloxy) pentane-1-sulfonate (Compound (B- One))

B-2: Triphenylsulfonium 1,1,2,2-tetrafluoro-5- (3-hydroxy-1-adamantanecarbonyloxy) pentane-1-sulfonate One compound (B-2))

B-3: Triphenylsulfonium 1,1,2,2-tetrafluoro-3- (1-adamantanecarbonyloxy) propane-1-sulfonate (Compound (B- 3))

B-4: Triphenylsulfonium 1,1,2,2-tetrafluoro-5- (2- (2-norbornanactoneoxycarbonyl) cyclohexanecarbonyloxy) pentane-1-sulfonate A compound represented by the formula (B-4)

b-1: Triphenylsulfonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) hexane-1-sulfonate

b-2: Triphenylsulfonium 1,1,2,2-tetrafluoro-4- (1-adamantanecarbonyloxy) butane-1-sulfonate

[[D] acid diffusion control agent]

D-1: Triphenylsulfonium salicylate (compound represented by the following formula (D-1)

[[E] Solvent]

E-1: Propylene glycol monomethyl ether acetate

E-2: Cyclohexanone

E-3:? -Butyrolactone

[Example 4]

, 100 parts by mass of the polymer (A-1), 10.4 parts by mass of the (B-1) acid generator as the acid generator, 3 parts by mass of the (C-1) 7.3 parts by mass of (D-1) as a solvent and 2,600 parts by mass of (E-1) as the solvent [E], 1,100 parts by mass of (E-2) and 200 parts by mass of (E-3) were mixed to obtain a homogeneous solution. Thereafter, the resultant was filtered using a membrane filter having a pore size of 200 nm to prepare a photoresist composition (J-1). The solid concentration of the photoresist composition was about 4%.

[Examples 5 to 17 and Comparative Examples 1 to 10]

(J-2) to (J-14) and comparative examples (CJ-1) to (CJ-1) were prepared in the same manner as in Example 1 except that the components and the amounts shown in Table 2 were used. CJ-10).

&Lt; Formation of resist pattern &

The photoresist compositions of the obtained examples and comparative examples were coated on a 12-inch silicon wafer on which a lower layer antireflection film (ARC66, manufactured by Nissan Chemical Industries, Ltd.) was formed, SB was carried out at 120 캜 for 60 seconds, Film. Next, the resist film was patterned using a ArF excimer laser immersion lithography apparatus (NSR-S610C, manufactured by Nikon) under the conditions of NA = 1.3, iNA = 1.27, ratio = 0.800, Crosspole, And exposed through a 1 L / 1 S mask. After the exposure, PEB was performed at the temperature shown in Table 2 for 60 seconds. Thereafter, development, water washing and drying were performed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide to form a positive resist pattern.

<Evaluation>

Defects in the exposed portion of the formed resist pattern were measured using a defect detection device (KLA2351, manufactured by KLA TENCOR). Further, the detected defects were classified into those judged as development defects originating from resist and those originating from externals by using a defect evaluation device (SEM Vision G3, manufactured by KLA Tencor), and the number of development defects originating from the resist was classified as development defects (Unit: number of wafers). The numerical values of the number of developed defects are shown together in Table 2.

As is clear from Table 2, it was confirmed that the photoresist composition of the examples can significantly reduce the number of developed defects compared with the photoresist composition of the comparative example.

According to the present invention, it is possible to provide a photoresist composition and a resist pattern forming method capable of suppressing the occurrence of development defects. Further, the acid generator of the present invention can be preferably used as a component of the photoresist composition. Accordingly, the photoresist composition, the method for forming a resist pattern, and the acid generator can be preferably used in the pattern formation in a semiconductor field and the like where progressively more and more miniaturization proceeds.

Claims (7)

A polymer having a structural unit (I) comprising an acid dissociable group [A], and
[B] An acid generator comprising a compound represented by the following formula (1)
Lt; / RTI &gt;

(In the formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that part or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the aliphatic hydrocarbon group may be an aliphatic heterocyclic ring is chukhwan the recall, X is ^{** - (X 2 -R ')} n -X 1 - and, X ¹ - is a -COO- or -O-, X ² is -COO- Or -O-, and R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the carbon-carbon double bond of the alicyclic hydrocarbon group and a may be an aliphatic heterocyclic ring is chukhwan, n is 0 or 1, and ** represents a site bonded to the R ^1, * represents the site binding to the R ¹ side, R ² is at least -CFR ³ - A divalent straight-chain fluorinated carbonized product in which two fluorine atoms are bonded to the carbon atom at the side terminal and the number of carbon atoms is even Scavenging and, R ³ is a fluorine atom, M ⁺ is a monovalent cation Im) The process according to claim 1, wherein R ² in the above formula (1) is 1,1-difluoro-1,2-ethanediyl, 1,1,2,2-tetrafluoro-1,2-ethane Diethyl, 1,1-difluoro-1,4-butanediyl, 1,1,2,2-tetrafluoro-1,4-butanediyl, 1,1-difluoro-1,6 -Hexanediyl group or a 1,1-difluoro-1,8-octanediyl group. The photoresist composition according to claim 1, wherein the compound represented by the formula (1) is represented by the following formula (1-1).

(Wherein R ¹ , X and M ⁺ are as defined in the above formula (1), and R ^A is a methylene group or a 1,3-propanediyl group) The positive resist composition according to any one of claims 1 to 3, wherein M ⁺ in the formula (1) is a sulfonium cation represented by the following formula (2-1) and an iodine represented by the following formula (2-2) And at least one cation selected from the group consisting of a transition metal compound and a transition metal compound.

(In the formula (2-1), R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group and the aryl group Or any two or more of R ⁴ , R ⁵ and R ⁶ may be bonded to each other to form a ring structure together with the sulfur atom to which they are bonded,
In the formula (2-2), R ⁷ and R ⁸ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms, and some or all of the hydrogen atoms of the alkyl group and the aryl group may be substituted And R &lt; ⁷ &gt; and R &lt; ⁸ &gt; may be bonded to each other to form a ring structure together with the iodine atom to which they are bonded) The photoresist composition according to any one of claims 1 to 3, wherein the structural unit (I) is represented by the following formula (3).

(3), R ⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R ¹⁰ , R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 10 carbon atoms or a monovalent An alicyclic hydrocarbon group wherein R ¹¹ and R ¹² may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded) (1) a step of forming a resist film on a substrate using the photoresist composition according to any one of claims 1 to 3,
(2) exposing the resist film through a photomask, and
(3) a step of developing the exposed resist film
And forming a resist pattern on the resist pattern. An acid generator comprising a compound represented by the following formula (1).

(In the formula (1), R ¹ is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that part or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the aliphatic hydrocarbon group may be an aliphatic heterocyclic ring is chukhwan the recall, X is ^{** - (X 2 -R ')} n -X 1 - and, X ¹ - is a -COO- or -O-, X ² is -COO- Or -O-, and R 'is a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, with the proviso that some or all of the hydrogen atoms of the alicyclic hydrocarbon group may be substituted, and the carbon-carbon double bond of the alicyclic hydrocarbon group and a may be an aliphatic heterocyclic ring is chukhwan, n is 0 or 1, and ** represents a site bonded to the R ^1, * represents the site binding to the R ¹ side, R ² is at least -CFR ³ - A divalent straight-chain fluorinated carbonized product in which two fluorine atoms are bonded to the carbon atom at the side terminal and the number of carbon atoms is even Scavenging and, R ³ is a fluorine atom, M ⁺ is a monovalent cation Im)