JP2009271253A - Liquid immersion exposure resist composition and patterning method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid immersion exposure resist composition having less fallen resist patterns and deteriorated pattern profiles and reducing its dissolution into the immersing liquid when making immersion exposure, and also to provide a patterning method using it. <P>SOLUTION: The liquid immersion exposure resist composition contains (A) a resin having repeated units of a specific cyclo alkyl structure manufactured by using a solvent selected from a group consisting of chained ketone, cyclic ketone, cyclic ether and cyclic ether as the polymerizing solvent, and decomposed by acid and increasing the solubility in an alkali developing solution, and (B) a compound generating acid when irradiated with active light or radiation. Further, the patterning method uses the composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resist composition for immersion exposure and a pattern formation using the same, which are used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal and a thermal head, and a lithography process for other photo applications. It is about the method. In particular, the present invention relates to a resist composition for immersion exposure suitable for exposure with an immersion projection exposure apparatus using far ultraviolet light having a wavelength of 300 nm or less as a light source, and a pattern forming method using the same.

With the miniaturization of semiconductor elements, the exposure light source has become shorter in wavelength and the projection lens has a higher numerical aperture (high NA). Currently, an exposure machine with NA 0.84 using an ArF excimer laser having a 193 nm wavelength as a light source has been developed. ing. The relationship between the numerical aperture, resolving power, and depth of focus can be expressed by the following equation as is generally well known.
(Resolving power) = k ₁ · (λ / NA)
(Depth of focus) = ± k ₂ · λ / NA ²
Where λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ and k ₂ are coefficients related to the process.

An exposure machine using a F ₂ excimer laser having a wavelength of 157 nm as a light source has been studied for higher resolution by further shortening the wavelength. Lens materials and resists used in the exposure apparatus for shorter wavelength have been studied. Since the materials used in the process are very limited, the manufacturing cost of the apparatus and the materials is increased, the quality stabilization is very difficult, and an exposure apparatus and resist having sufficient performance and stability are desired.

Conventionally, as a technique for increasing the resolving power in an optical microscope, a so-called immersion method in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between a projection lens and a sample is known.
When immersion is performed, λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ, It can be expressed by the following formula.
(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
(Depth of focus) = ± k ₂ · (λ ₀ / n) / NA ₀ ²
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion. This is effective for all pattern shapes, and can be combined with a super-resolution technique such as a phase shift method and a modified illumination method which are currently being studied.

Examples of apparatuses in which this effect is applied to transfer of a fine image pattern of a semiconductor element are introduced in Patent Document 1, Patent Document 2, and the like.
Recent progress in immersion exposure technology is reported in Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, and the like. In the case of using an ArF excimer laser as a light source, pure water (refractive index of 1.44 at 193 nm) is considered to be most promising as an immersion liquid in terms of handling safety and transmittance and refractive index at 193 nm.
When an F ₂ excimer laser is used as a light source, a solution containing fluorine has been studied from the balance between transmittance and refractive index at 157 nm. However, a sufficient product has not yet been seen in terms of environmental safety and refractive index. It has not been issued. From the degree of immersion effect and the degree of completeness of the resist, the immersion exposure technique is considered to be installed in the ArF exposure machine earliest.

Since the resist for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for a resist in order to compensate for sensitivity reduction due to light absorption. An example of a positive chemical amplification image forming method is as follows. The acid generator in the exposed area is decomposed by exposure to generate acid, and the generated acid is reacted by a post exposure bake (PEB) reaction catalyst. Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.
The ArF excimer laser (193 nm) resist using this chemical amplification mechanism is now becoming the mainstream, but when immersion exposure is performed, the formed line pattern collapses, resulting in a pattern that becomes a defect during device manufacturing. There was a problem of falling.
Further, in order to improve dry etching resistance, it is necessary to improve the carbon density of the monomer, but when performing polymerization using a monomer having a hydrophobic group such as an alicyclic group having a high carbon density and a polar group such as a hydroxyl group. There is a problem that the solvent solubility of the monomer deteriorates. In Patent Document 3, tetrahydrofuran or the like is used as a polymerization solvent used for producing a resist resin. Further, Patent Document 4 describes a cyclic ketone solvent as a polymerization solvent for improving the solvent solubility of the monomer. However, depending on the monomer type, the solvent solubility is not sufficient.

  It is pointed out that when chemically amplified resist is applied to immersion exposure, the resist layer comes into contact with the immersion liquid at the time of exposure, so that the resist layer is altered and components that adversely affect the immersion liquid are leached from the resist layer. Has been. Patent Document 5 describes an example in which resist performance is changed by immersing a resist for ArF exposure in water before and after exposure, and points out a problem in immersion exposure.

JP-A-57-153433 JP-A-7-220990 Japanese Patent Laid-Open No. 10-307400 JP 2004-175981 A International Publication No. 04/068242 Pamphlet Proc. SPIE, 2002, Vol. 4688, p. 11 J.Vac.Sci.Tecnol.B 17 (1999) Proc. SPIE, 2000, Vol. 3999, p. 2

  SUMMARY OF THE INVENTION An object of the present invention is to provide a resist composition in which resist pattern collapse and profile deterioration are small in immersion exposure, and dissolution into the immersion liquid is suppressed, and a pattern forming method using the same. is there.

  As a result of intensive studies, the present inventor has produced a resin produced by polymerizing a resin having a specific repeating unit using a specific polymerization solvent when producing a resin used in a resist composition by polymerization. The present invention was completed by finding that the resist composition using the resist has little deterioration in the profile and pattern collapse performance and the elution into the immersion liquid is suppressed.

  The present invention is as follows.

(1) (A) A repeating unit represented by the following general formula (I) produced using a solvent selected from the group consisting of a chain ketone, a cyclic ketone, a chain ether and a cyclic ether as a polymerization solvent And a resin that decomposes by the action of an acid and increases the solubility in an alkali developer, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation. Resist composition.

In general formula (I),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.

  (2) The resist composition for immersion exposure according to (1), wherein the polymerization solvent is a chain ketone or a cyclic ketone.

  (3) The resist composition for immersion exposure as described in (1), wherein the polymerization solvent is a mixed solvent containing a cyclic ketone and a chain ketone.

  (4) The resist composition for immersion exposure according to any one of (1) to (3), wherein the resin of component (A) further has a repeating unit having a lactone group.

  (5) The resist composition for immersion exposure according to any one of (1) to (4), wherein the resin as the component (A) further has a repeating unit having a hydroxyl group.

(6) A monomer containing a monomer represented by the following general formula (Im) is polymerized in a polymerization solvent containing a solvent selected from the group consisting of a chain ketone, a cyclic ketone, a chain ether and a cyclic ether. A method for producing a resin which is decomposed by the action of an acid and has increased solubility in an alkaline developer.

In general formula (Im),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.

  (7) A pattern forming method comprising: forming a resist film using the resist composition according to any one of (1) to (5); and subjecting the resist film to immersion exposure and development.

  The preferred embodiments of the present invention will be further described below.

  (8) The resist composition for immersion exposure according to any one of (1) to (5), wherein a polymerization solvent having two or more components is used.

  (9) The resist composition for immersion exposure as described in (1) to (5), wherein a polymerization solvent solvent having three or more components is used.

  According to the present invention, there can be provided a resist composition and a pattern formation method using the resist composition in which the resist pattern collapses and the profile is hardly deteriorated in the immersion exposure, and the elution into the immersion liquid is suppressed.

Hereinafter, the best mode for carrying out the present invention will be described.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

(A) Resin that decomposes by the action of an acid and increases its solubility in an alkaline developer In the present invention, a resin that decomposes by the action of an acid and increases its solubility in an alkaline developer (hereinafter referred to as “resin”) (A) ") has a group (acid-decomposable group) that decomposes by the action of an acid to generate an alkali-soluble group.
The resin (A) may have an acid-decomposable group in the main chain or side chain of the resin, or in both the main chain and the side chain, but preferably in the side chain.
A preferred group as the acid-decomposable group is a group in which a hydrogen atom of an alkali-soluble group such as a —COOH group or a —OH group is substituted with a group capable of leaving with an acid.
Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ , R ₃₆ and R ₃₉ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
In the present invention, the acid-decomposable group is preferably an acetal group or a tertiary ester group.

  Resin (A) has a repeating unit represented by the following general formula (I) as a repeating unit having an acid-decomposable group.

In general formula (I),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.

In the general formula (I), the alkyl group represented by R ¹ is preferably one having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Further, it may have a hydroxyl group, a halogen atom (more preferably a fluorine atom), a cyano group or the like. R ¹ is preferably a hydrogen atom or a methyl group.
The alkyl group for R ² is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 or 2 carbon atoms.
Examples of the cycloalkyl group having 5 or 6 carbon atoms of CA include a cyclopentyl group and a cyclohexyl group.
The divalent linking group of A is selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, or a urea group, or two or more A combination of groups can be mentioned.
A is preferably a single bond or —COO—CH ₂ —, and more preferably a single bond.
The halogen atom for R ³ is preferably a fluorine atom.
Examples of the alkyl group for R ³ include a methyl group, an ethyl group, a propyl group, and an isopropyl group. The substituent of R ³ can be present at any position on the ring.
The cycloalkyl group represented by R ³ is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group. .
n represents 0 or a positive integer. That is, the cycloalkyl group represented by CA may have a number within the range that can substitute the substituent R ³ . n is preferably 0 or 1.
The alkyl group and cycloalkyl group in R ² and R ³ may further have a substituent. Examples of the substituent which may be included include a halogen atom, a hydroxyl group, a nitro group, a cyano group, and a carboxy group. Group, substituted carbonyl group, cycloalkyl group (preferably 3 to 10 carbon atoms), aryl group (preferably 6 to 14 carbon atoms), alkoxy group (preferably 1 to 10 carbon atoms), substituted acyl group (preferably carbon Number 2-20), a substituted acyloxy group (preferably having 2 to 10 carbon atoms), a substituted alkoxycarbonyl group (preferably having 2 to 20 carbon atoms), a substituted aminoacyl group (preferably having 2 to 10 carbon atoms), and the like. Examples of the substituent of the cyclic structure in the aryl group, cycloalkyl group and the like include an alkyl group (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted carbonyl group, substituted acyl group, substituted acyloxy group, and substituted alkoxycarbonyl group include 1 or 2 alkyl groups (preferably having 1 to 10 carbon atoms). Examples of the substituent in the substituted aminoacyl group include one or two alkyl groups (preferably having 1 to 10 carbon atoms).

  As for content of the repeating unit represented by general formula (I), 15-60 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 20-50 mol%.

  Hereinafter, although the specific example of the repeating unit represented by general formula (I) is given, this invention is not limited to this.

The resin (A) preferably further has a repeating unit having an acid-decomposable group in addition to the repeating unit represented by the general formula (I).
The repeating unit having an acid-decomposable group is preferably a repeating unit represented by the following general formula (AI).

In general formula (AI),
Xa ₁ represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group (straight or branched) or a cycloalkyl group (monocyclic or polycyclic).
At least two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group (monocyclic or polycyclic, except for a cyclopentyl group and a cyclohexyl group).

Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.
The alkyl group of Rx _{1 to} Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.
Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group. A cycloalkyl group is preferred.
Examples of the cycloalkyl group formed by combining at least two of Rx _{1 to} Rx ₃ include a monocyclic cycloalkyl group such as cycloheptyl group, norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, adamantyl group A polycyclic cycloalkyl group such as is preferable.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to form the above-described cycloalkyl group.

  The content of the repeating unit having an acid-decomposable group other than the repeating unit represented by formula (I) is preferably from 20 to 50 mol%, more preferably from 25 to 45 mol%, based on all repeating units in the polymer. It is.

  Although the specific example of the repeating unit which has an acid-decomposable group used preferably is shown below, this invention is not limited to this.

  The resin (A) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The resin (A) preferably has a repeating unit having a lactone group.
Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (Rb ₂ ) may be bonded to form a ring.

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AL).

In general formula (AL),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by. Ab ₁ is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  The content of the repeating unit having a lactone group is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having a lactone group are listed below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone group include the following repeating units. By selecting the optimum lactone group, the pattern profile and the density dependence become good.

The resin (A) preferably has a repeating unit having a hydroxyl group or a cyano group, and more preferably has a repeating unit having a hydroxyl group. This improves the substrate adhesion and developer compatibility. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

  The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 10 with respect to all repeating units in the polymer. ˜25 mol%.

  Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

  The resin (A) preferably has a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for content of the repeating unit which has an alkali-soluble group, 0-20 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

  Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, more preferably, a repeating unit having at least two groups selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group Preferably, it is a repeating unit having a cyano group and a lactone group. Particularly preferred is a repeating unit having a structure in which a cyano group is substituted on the lactone structure of (LCI-4).

  The resin (A) may further have a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a repeating unit include 1-adamantyl (meth) acrylate, diamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate repeating units.

  Resin (A) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution, heat resistance, sensitivity, etc., which are general required characteristics of resist, in addition to the above repeating structural units. For this purpose, various repeating structural units can be included.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc. can be mentioned.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resin (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and the general required performance of the resist, resolving power, heat resistance, sensitivity. It is set appropriately in order to adjust etc.

  When the resist composition for immersion exposure of the present invention is used for ArF exposure, the resin (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  The resin (A) is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, 15 to 60 mol% of the repeating unit represented by the general formula (I), 20 to 50 mol% of the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (AI), and a lactone 20 to 50 mol% of (meth) acrylate repeating units having a group, 5 to 30 mol% of (meth) acrylate repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and other (meth) It is a copolymer containing 0 to 20 mol% of an acrylate repeating unit.

  When the resist composition for immersion exposure of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, high energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) has the general formula (I In addition to the repeating unit represented by), it is preferable to further have a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred examples of the repeating unit having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, a repeating unit of (meth) acrylic acid tertiary alkyl ester, and the like. The repeating unit by 2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate is more preferable.

<Production method of resin>
Resin (A) can be manufactured in accordance with a conventional method (for example, radical polymerization). For example, as a general production method, a monomer containing a monomer represented by the following general formula (Im) and a polymerization initiator are dissolved in a solvent and heated to perform polymerization. Examples thereof include a dropping polymerization method in which a solution of a polymerization initiator is added dropwise over 1 to 10 hours, and the dropping polymerization method is preferable.

In general formula (Im),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.

In formula ^{(Im), R 1 ~R 3} , CA, A and n are in the general formula ^{(I), R 1 ~R 3} , CA, is synonymous with A and n.

The polymerization solvent is produced using a solvent selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers.
Examples of chain ketones include 2-heptanone, methyl ethyl ketone, and methyl isobutyl ketone, and 2-heptanone is preferable.
Examples of the cyclic ketone include cyclopentanone, 3-methyl-2-cyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, cycloheptanone, cyclooctanone, and isophorone. Cyclohexanone and cycloheptanone.
Examples of the chain ether include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl methoxypropionate, and ethoxypropion. Examples include ethyl acid.
Examples of cyclic ethers include tetrahydrofuran and dioxane.
The use of a solvent selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers as the polymerization solvent is selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers. The solvent may be used alone, or a mixed solvent in which two or more solvents selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers are mixed, chain ketones, A mixed solvent of at least one solvent selected from the group consisting of cyclic ketones, chain ethers, and cyclic ethers and other solvents may be used.
Other solvents that can be mixed with at least one solvent selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers include, for example, ethylene dichloride,
γ-butyrolactone, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone and the like can be mentioned.
In a mixed solvent of at least one solvent selected from the group consisting of chain ketones, cyclic ketones, chain ethers and cyclic ethers with other solvents, chain ketones, cyclic ketones, chain ethers and cyclic ethers The content of at least one solvent selected from the group consisting of is preferably 20 to 100% by mass, and more preferably 60 to 100% by mass.
As the polymerization solvent, chain ketones and cyclic ketones are more preferable, and cyclic ketones are particularly preferable.
Even more preferably, the polymerization solvent is a mixed solvent containing a cyclic ketone and a chain ether. The mixing ratio (mass ratio) of the cyclic ketone and the chain ether is preferably 8: 2 to 3: 7, more preferably 7: 3 to 4: 6, and particularly preferably 6: 4 to 5: 5.
The polymerization solvent according to the present invention is excellent in compatibility with any of the monomer mixture, the polymerization initiator and the obtained resin, and can improve the reaction rate of the obtained resin.
The boiling point of the polymerization solvent is preferably from 100 ° C. to 200 ° C., more preferably from 120 ° C. to 180 ° C., particularly preferably from 130 ° C. to 160 ° C.

  In the present invention, when a resin used for a resist composition is produced by polymerization, a resin having a specific repeating unit is polymerized using a specific polymerization solvent, and the resulting resin is converted into a resist composition. When used in the above, it is possible to prepare a resist composition with little deterioration in profile and pattern collapse performance and suppressed elution into the immersion liquid.

Commercially available radical initiators (azo initiators, peroxides, etc.) are used as the polymerization initiator. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is more preferable. Preferred polymerization initiators include azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1 '-Azobis (cyclohexane-1-carbonitrile), dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovalerate), tert-butyl peroctoate, 1, Examples thereof include 1'-azobis- (cyclohexane-1-carbonitrile, 1-[(1-diazo-1-methylethyl) azo] formamide, etc. A particularly preferred polymerization initiator is azobisisobutyronitrile. And dimethyl 2,2′-azobis (2-methylpropionate), etc. The polymerization initiators are used alone or in combination. be able to.
A chain transfer agent such as a thiol compound may be used in combination with the polymerization initiator. If desired, an initiator may be added or added in portions.
The usage-amount of a polymerization initiator is not restrict | limited in particular, For example, it is 0.1-10 mass parts with respect to 100 mass parts of monomers, Preferably it is 1-5 mass parts.

The concentration of the reaction is preferably 5 to 50% by mass and more preferably 10 to 30% by mass from the viewpoint that the mass average molecular weight of the obtained resin can be easily controlled. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon.

The reaction liquid containing the resin obtained by the polymerization reaction is dropped into a large amount of these solvents using a single or mixed solvent such as hexane, heptane, ethyl acetate, isopropanol, methanol, water, etc. to precipitate the resin. Then, the resin (A) of the present invention can be obtained by filtering, washing and drying the obtained precipitate. Although this step may be unnecessary depending on circumstances, it is effective for removing unreacted monomers (monomers), polymerization initiators and the like remaining in the reaction solution. If these unreacted substances remain as they are, there is a possibility that the resist performance may be adversely affected.

The weight average molecular weight of the resin (A) according to the present invention is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, most preferably 5, as a polystyrene conversion value by GPC method. 000 to 15,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and developability is deteriorated, or viscosity is increased and film forming property is deteriorated. Can be prevented.
Molecular weight distribution is 1-5 normally, Preferably it is 1-2, More preferably, it is 1.3-2. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.
The structure in particular of resin (A) is not restrict | limited, Any of a random copolymer, a block copolymer, and an alternating copolymer may be sufficient.

In the resist composition for immersion exposure according to the present invention, the blending amount of the resin (A) in the entire composition is preferably 50 to 99.99% by mass, more preferably 60 to 99.0% by mass in the total solid content. It is.
In the present invention, the resin (A) may be used alone or in combination.

<Resist composition>
The resist composition for immersion exposure of the present invention comprises the above-mentioned resin (A) and (B) a compound that generates an acid upon irradiation with actinic rays or radiation.

(B) Compound that generates acid upon irradiation with actinic ray or radiation The resist composition for immersion exposure of the present invention is a compound that generates acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”). Containing.
Examples of such an acid generator include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or an actinic ray or radiation used for a microresist. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) can be exemplified.

In general formula (ZI):
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{− and the} like. An organic anion having a carbon atom is preferable.

  Preferred organic anions include organic anions represented by the following general formulas (AN1) to (AN4).

In general formulas (AN1) to (AN2),
Rc ₁ represents an organic group.
Examples of the organic group in Rc ₁ include those having 1 to 30 carbon atoms, and preferably an alkyl group, an aryl group, or a plurality of which may be substituted is a single bond, —O—, —CO ₂ —, _{-S -, - SO 3 -,} - SO 2 N (Rd 1) - can be exemplified linked group a linking group such as.
Rd ₁ represents a hydrogen atom or an alkyl group, and may form a ring structure with the bonded alkyl group or aryl group.
More preferred as the organic group for Rc ₁ is an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. When Rc ₁ has 5 or more carbon atoms, it is preferable that at least one carbon atom has a hydrogen atom, not all hydrogen atoms are substituted with fluorine atoms, and the number of hydrogen atoms is fluorine. More preferably than atoms. By not having a perfluoroalkyl group having 5 or more carbon atoms, ecotoxicity is reduced.
A particularly preferred embodiment of Rc ₁ is a group represented by the following general formula.

In the above general formula,
Rc ₆ is substituted with a perfluoroalkylene group having 4 or less carbon atoms, more preferably 2 to 4, more preferably 2 to 3, or 1 to 4 fluorine atoms and / or 1 to 3 fluoroalkyl groups. Represents a substituted phenylene group.
Ax represents a single bond or a divalent linking group (preferably —O—, —CO ₂ —, —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) —). Rd ₁ represents a hydrogen atom or an alkyl group, and may combine with Rc ₇ to form a ring structure.
Rc ₇ represents a hydrogen atom, a fluorine atom, an optionally substituted linear or branched alkyl group, an optionally substituted monocyclic or polycyclic cycloalkyl group, or an optionally substituted aryl group. The optionally substituted alkyl group, cycloalkyl group and aryl group preferably do not contain a fluorine atom as a substituent.

In general formulas (AN3) and (AN4),
Rc ₃ , Rc ₄ and Rc ₅ each independently represents an organic group.
Preferred examples of the organic group for Rc ₃ , Rc ₄ and Rc ₅ include the same organic groups as those for Rc ₁ .
Rc ₃ and Rc ₄ may combine to form a ring.
Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group, a cycloalkylene group, and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group. By combining Rc ₃ and Rc ₄ to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved, which is preferable.

In formula (ZI), the carbon number of the organic group as R _201, R ₂₀₂ and R ₂₀₃ is generally from 1 to 30, preferably 1 to 20.
It is also possible to form the two members ring structure of the R ₂₀₁ to R _203, an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

In addition, the compound which has two or more structures represented by general formula (Z1) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  Further preferred examples of the component (Z1) include compounds (ZI-1), (ZI-2), and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or R ₂₀₁
Some of to R ₂₀₃ is an aryl group with the remaining being an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.
Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, particularly preferably. They are a C1-C4 alkyl group and a C1-C4 alkoxy group. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, and particularly preferably a linear group. A branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group). The alkyl group as R ₂₀₁ to R ₂₀₃ is a straight-chain or branched 2-oxoalkyl group is preferably an alkoxycarbonyl methyl group.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cyclic 2-oxoalkyl group.
The 2-oxoalkyl group as R _{201 to} R ₂₀₃ may be linear, branched or cyclic, and preferably a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group Can be mentioned.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group.
Any two or more of R _1c to R _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be linear or branched, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Examples thereof include linear and branched alkyl groups (for example, methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).
Preferable examples of the cycloalkyl group as R _{1c to} R _7c include a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).
The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).
Preferably, any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of carbon numbers of R _{1c to} R _5c is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is preferably a cyclic 2-oxoalkyl group.
Examples of the linear, branched, or cyclic 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ₂₀₄ to R _207, a phenyl group, a naphthyl group, more preferably a phenyl group.
The alkyl group as R ₂₀₄ to R ₂₀₇ may be linear, it may be either branched, preferably a straight-chain or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (ZI).

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formulas (ZIV), (ZV), and (ZVI) can be further exemplified.

In the general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ represents an alkyl group, a cycloalkyl group, or an aryl group.
R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or an electron-withdrawing group. R ₂₀₉ is preferably an aryl group. R ₂₁₀ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Of the compounds that generate an acid upon irradiation with actinic rays or radiation, more preferred are compounds represented by general formulas (ZI) to (ZIII), and even more preferred are compounds represented by general formula (ZI). And particularly preferred are compounds represented by the general formulas (ZI-1) to (ZI-3).
Furthermore, the compound which generate | occur | produces the acid represented by the following general formula (AC1)-(AC3) by irradiation of actinic light or a radiation is preferable.

That is, as a particularly preferred embodiment of the acid generator, in the compound represented by the general formula (ZI), X ⁻ is an anion selected from the general formulas (AN1), (AN3), and (AN4). It is a certain compound.

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, examples of particularly preferable compounds are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more.
The content of the acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 7% by mass, based on the total solid content of the resist composition. %.

Solvent In the present invention, the above-described components are dissolved in a solvent to prepare a resist composition for immersion exposure.
Solvents that can be used when preparing the resist composition for immersion exposure by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, alkoxypropion Organic solvents such as alkyl acid, cyclic lactone (preferably having 4 to 10 carbon atoms), monoketone compound (preferably having 4 to 10 carbon atoms) which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, alkyl pyruvate, etc. be able to.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

  Examples of the monoketone compound that may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3- Methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methyl Preferred is cycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

Basic Compound The resist composition for immersion exposure according to the present invention preferably contains a basic compound in order to reduce a change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) to (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.
As the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group. Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group,
Examples thereof include an aralkyl group, an acyloxy group, and an aryloxy group. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.
It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

In the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group, the sulfonic acid ester group may be any of alkyl sulfonic acid ester, cycloalkyl group sulfonic acid ester, and aryl sulfonic acid ester. In the case of an alkyl sulfonate ester, the alkyl group has 1 to 20 carbon atoms. In the case of a cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms. In the case of an aryl sulfonate ester, the aryl group has 6 carbon atoms. ~ 12 are preferred. Alkyl sulfonic acid ester, cycloalkyl sulfonic acid ester, and aryl sulfonic acid ester may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid. An ester group is preferred.
It is preferable to have at least one oxyalkylene group between the sulfonate group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of the resist composition for immersion exposure, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

Surfactant The resist composition for immersion exposure of the present invention preferably further contains a surfactant, and is a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, fluorine-containing surfactant). It is more preferable to contain any one or two or more surfactants having both atoms and silicon atoms.

When the resist composition for immersion exposure of the present invention contains the above-mentioned surfactant, a resist pattern with good sensitivity and resolution, and less adhesion and development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. Can be given.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 58,244
The surfactant described in the specification of No. 51 can be mentioned, and the following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189 , F113, F110, F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  The amount of the surfactant used is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of the resist composition for immersion exposure (excluding the solvent).

Hydrophobic resin It is preferable to add a hydrophobic resin (HR) to the resist composition for immersion exposure according to the present invention. As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when used as a resist film is improved, and the followability of immersion water is improved. Can be made. As the hydrophobic resin (HR), any resin can be used as long as the receding contact angle on the surface can be improved by adding it, but a resin having at least one of a fluorine atom and a silicon atom is preferable. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film falls within the above range, but is 0.1 to 10% by mass based on the total solid content of the resist composition for immersion exposure. Preferably, it is 0.1-5 mass%. Hydrophobic resin (HR) is ubiquitous at the interface as described above, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule, and polar / nonpolar substances are mixed uniformly. There is no need to contribute.
The receding contact angle is the contact angle measured when the contact line at the droplet-substrate interface recedes, and is useful for simulating the ease of droplet movement in a dynamic state. It is generally known. In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. Generally, it can be measured using a contact angle measurement method called an expansion / contraction method.
In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the resist film becomes important, and the resist is required to have the capability of following the high-speed scanning of the exposure head without leaving droplets.

  The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.

The hydrophobic resin (HR) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.

  Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.
Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.
Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

Hereinafter, although the specific example of the repeating unit which has a fluorine atom is shown, this invention is not limited to this.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .
X ₂ represents —F or —CF ₃ .

The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.
Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group is used alone or in combination of two or more groups. A combination is mentioned.
n represents an integer of 1 to 5.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is given, this invention is not limited to this. In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .

Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

(X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) ) And a methylene group.
Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. Examples include repeating units in which an alkali-soluble group is bonded to the chain. Furthermore, a polymerization initiator or a chain transfer agent having an alkali-soluble group can be used at the time of polymerization to be introduced at the end of the polymer chain. Is also preferable.
The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having an alkali-soluble group (x) are shown below, but the present invention is not limited thereto.

(Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride group, an acid imide group, and the like, and preferably a lactone A group having a structure.
As the repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer, an alkali is added to the main chain of the resin, such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator having a repeating unit to which a group (y) that decomposes by the action of the developer and increases the solubility in an alkali developer is bonded, or a group (y) that increases the solubility in an alkali developer And a chain transfer agent used at the time of polymerization are preferably introduced at the end of the polymer chain.
The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having a lactone structure exemplified for the resin of the component (A).

  In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group listed for the resin of the component (A). . In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably 1 to 80 mol%, more preferably 10 to 10%, based on all repeating units in the polymer. 80 mol%, more preferably 20 to 60 mol%.

  The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (III).

In general formula (III):
R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.

In general formula (III), the alkyl group represented by R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.
When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  As for the hydrophobic resin (HR), it is preferable that the residual monomer and oligomer components are 0 to 10% by mass, more preferably, as in the resin of the component (B), there are few impurities such as metals. Is more preferably 0 to 5% by mass and 0 to 1% by mass. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  As the hydrophobic resin (HR), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is carried out using the same solvent as the solvent used in the resist composition for immersion exposure according to the present invention. Thereby, the generation of particles during storage can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

  Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of the repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

Carboxylic acid onium salt The resist composition for immersion exposure in the present invention may contain a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, as the carboxylic acid onium salt, an iodonium salt and a sulfonium salt are preferable. Furthermore, it is preferable that the carboxylate residue of the carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluoro-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass, based on the total solid content of the composition. %.

Dissolution-inhibiting compound having a molecular weight of 3000 or less that decomposes by the action of an acid to increase the solubility in an alkali developer. Dissolution-inhibiting compound having a molecular weight of 3000 or less that decomposes by the action of an acid to increase the solubility in an alkali developer. (Hereinafter, also referred to as “dissolution inhibitor compound”), such as a cholic acid derivative containing an acid-decomposable group described in ProceedingofSPIE, 2724,355 (1996), in order not to lower the permeability of 220 nm or less. An alicyclic or aliphatic compound containing an acid-decomposable group is preferred. Examples of the acid-decomposable group and alicyclic structure are the same as those described for the component (B) resin.

  When the resist composition for immersion exposure of the present invention is exposed with a KrF excimer laser or irradiated with an electron beam, it preferably contains a structure in which the phenolic hydroxyl group of the phenol compound is substituted with an acid-decomposable group. As a phenol compound, what contains 1-9 phenol frame | skeleton is preferable, More preferably, it contains 2-6 pieces.

  The molecular weight of the dissolution inhibiting compound in the present invention is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution inhibiting compound is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the solid content of the resist composition for immersion exposure.

  Specific examples of the dissolution inhibiting compound are shown below, but the present invention is not limited thereto.

Other Additives In the resist composition for immersion exposure according to the present invention, a dye, a plasticizer, a photosensitizer, a light absorber, and a compound (for example, a molecular weight) that promotes solubility in a developer as necessary. 1000 or less phenolic compounds, alicyclic or aliphatic compounds having a carboxyl group) and the like can be contained.

Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to, for example, the methods described in JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, etc. It can be easily synthesized by those skilled in the art.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

Pattern Formation Method The resist composition for immersion exposure of the present invention is preferably used at a film thickness of 30 to 250 nm, more preferably at a film thickness of 30 to 200 nm, from the viewpoint of improving resolution. . Such a film thickness can be obtained by setting the solid content concentration in the resist composition for immersion exposure to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid content concentration in the resist composition for immersion exposure is generally 1 to 10% by mass, more preferably 1 to 8.0% by mass, and still more preferably 1.0 to 6.0% by mass. .

  The resist composition for immersion exposure according to the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a resist composition for immersion exposure is coated on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by an appropriate coating method such as a spinner or a coater, and dried. A film is formed.
The resist film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far ultraviolet light having a wavelength of 200 nm, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc. ArF excimer laser, F ₂ Excimer laser, EUV (13 nm), and electron beam are preferable.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

In the development step, an alkaline developer is used as follows. Examples of the alkali developer for the resist composition for immersion exposure include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate and aqueous ammonia, ethylamine, n-propylamine and the like. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium Alkaline aqueous solutions such as quaternary ammonium salts such as hydroxide and cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.
As the rinsing liquid, pure water can be used, and an appropriate amount of a surfactant can be added.
In addition, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

  In the present invention, exposure (immersion exposure) is performed by filling a liquid (immersion liquid) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. Any immersion liquid can be used as long as it has a refractive index higher than that of air, but pure water is preferred.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist film. Is an ArF excimer laser (wavelength; 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-mentioned viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist film on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light, the optical image projected on the resist film is distorted. . Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

In order to prevent the resist film from coming into direct contact with the immersion liquid between the resist film and the immersion liquid of the resist composition for immersion exposure according to the present invention, an immersion liquid hardly soluble film (hereinafter referred to as “top coat”). May also be provided. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.
From the viewpoint of 193 nm transparency, the top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HR) is also suitable as a top coat. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist film is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist film development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist film.
The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the topcoat may be a poorly soluble and non-water-soluble medium in the solvent used for the resist composition for immersion exposure. preferable. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.

Synthesis example 1
Under a nitrogen stream, 30 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 9.9 g of 2-cyano-2,6-norbornylcarbolactone-5-methacrylate, 4.7 g of 3-hydroxyadamantyl-1-methacrylate, 1.7 g of cyclohexyl methacrylate, 5.5 of 1-ethylcyclohexyl methacrylate, 8 mol% of polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 5 hours to 55 g of cyclohexanone. After completion of the dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise to a mixed solution of 900 m of methanol / 100 ml of water over 20 minutes. The precipitated powder was collected by filtration and dried to obtain 16.5 g of Resin (1). The weight average molecular weight of the obtained resin (1) was 8300 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.84.

Synthesis example 2
Under a nitrogen stream, 20 g of cyclohexanone and 20 g of propylene glycol monomethyl ether acetate were placed in a three-necked flask and heated to 80 ° C. To this, 9.9 g of 2-cyano-2,6-norbornylcarbolactone-5-methacrylate, 2.5 g of 3,5-dihydroxyadamantyl-1-methacrylate, 8.4 g of 1-ethylcyclopentyl acrylate, polymerization initiator V A solution prepared by dissolving 6 mol% of -601 (manufactured by Wako Pure Chemical Industries, Ltd.) in 35 g of cyclohexanone and 35 g of propylene glycol methyl ether acetate was added dropwise over 6 hours. After completion of the dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise over 20 minutes to a mixture of methanol 900 m / water 100 ml. The precipitated powder was collected by filtration and dried, yielding 16.7 g of Resin (2). The weight average molecular weight of the obtained resin (2) was 11000 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.78.

Synthesis example 3
Under a nitrogen stream, 15 g of cyclohexanone, 10 g of propylene glycol monomethyl ether and 20 g of propylene glycol monomethyl ether acetate were placed in a three-necked flask and heated to 80 ° C. To this, 14.9 g of 2-cyano-2,6-norbornylcarbolactone-5-methacrylate, 3.9 g of 3,5-dihydroxyadamantyl-1-methacrylate, 10.9 g of 1-ethylcyclopentyl methacrylate, cyclohexyl methacrylate 2. A solution prepared by dissolving 52 g of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries) in 25 g of cyclohexanone, 20 g of propylene glycol monomethyl ether, and 40 g of propylene glycol methyl ether acetate was added dropwise over 6 hours. After completion of the dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise over 20 minutes to a mixture of methanol 900 m / water 100 ml. The precipitated powder was collected by filtration and dried, yielding 26.2 g of Resin (12). The weight average molecular weight of the obtained resin (12) was 9200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.65.

  It manufactured on the conditions similar to the synthesis example 1 except having changed the monomer about resin (3)-(6). It manufactured on the conditions similar to the synthesis example 2 except having changed the monomer about resin (7)-(11). It manufactured on the conditions similar to the synthesis example 3 except having changed the monomer about resin (13)-(14).

  Hereinafter, the structures of the resins (1) to (14) are shown.

  Table 2 below shows the composition ratio (molar ratio, corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion for the resins (1) to (14).

Comparative Synthesis Example 1
Except having changed the monomer, resin was manufactured on the conditions similar to the synthesis example 1, and 13.5 g of comparative resin (1 ') was obtained. The weight average molecular weight of the comparative resin (1 ′) was 7200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.80.

Comparative Synthesis Example 2
Except having changed the monomer, resin was manufactured on the conditions similar to the synthesis example 1, and 12.5 g of comparative resin (2 ') was obtained. The weight average molecular weight of the comparative resin (2 ′) was 8500 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.85.

  The structures of the comparative resins (1 ′) to (2 ′) are shown below.

  Table 3 below shows the composition ratio (molar ratio, corresponding to each repeating unit in order from the left), weight average molecular weight, and degree of dispersion for the comparative resins (1 ') to (2').

Examples 1-14 and Comparative Examples 1-2
<Resist preparation>
The components shown in Tables 4 to 5 below were dissolved in a solvent, and a solution having a solid content concentration of 7% by mass was prepared for each, and this was filtered through a polyethylene filter having a pore size of 0.1 μm to prepare a positive resist solution. . The prepared positive resist composition was evaluated by the following method, and the results are shown in Tables 4-5.

  [Image performance test]

(Exposure conditions)
This condition is to form a resist pattern by an immersion exposure method using pure water.
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied and baked at 120 ° C. for 60 seconds to form a 200 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.85). Ultra pure water was used as the immersion liquid. Thereafter, heating was performed at 110 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern.

  About the obtained resist pattern, the pattern collapse performance and pattern profile were observed using the scanning electron microscope (Hitachi S-4800).

[Pattern collapse evaluation]
The exposure amount that reproduces the 85 nm line and space pattern is the optimal exposure amount, and the denser pattern of line and space 1: 1 and the isolated pattern of line and space 1:10 have a finer mask size when exposed at the optimal exposure amount. The line width (nm) at which the pattern is resolved without falling is defined as the limit pattern falling line width. A smaller value indicates that a finer pattern is resolved without falling, and pattern falling is less likely to occur.

[Profile shape evaluation method]
An isolated pattern of 85 nm was observed. A rectangular pattern was indicated by ◯, a slightly tapered pattern was indicated by △, and a film loss was indicated by x.

[Elution]
The prepared positive resist composition was applied to an 8-inch silicon wafer and baked at 120 ° C. for 60 seconds to form a 150 nm resist film. After exposing the resist film to 20 mJ / cm ² on the whole surface with an exposure machine having a wavelength of 193 nm, 5 ml of pure water deionized using an ultrapure water production apparatus (Milli-Q Jr., manufactured by Millipore Japan) It was dripped in. Water was placed on the resist film for 50 seconds, the water was collected, and the acid elution concentration was quantified by LC-MS.
LC equipment; Waters 2695
MS equipment: esquire 3000plus manufactured by Bruker Daltonics
The detection intensity of an ion species having a molecular weight corresponding to an anion was measured with the LC-MS apparatus, and the amount of acid eluted was calculated.

The symbols in the table are as follows.
The acid generator corresponds to that exemplified above.

N-1: N, N-dibutylaniline N-2: N, N-dihexylaniline N-3: 2,6-diisopropylaniline N-4: tri-n-octylamine N-5: N, N-dihydroxyethyl Aniline N-6: 2,4,5-triphenylimidazole N-7: Tris (methoxyethoxyethyl) amine N-8: 2-phenylbenzimidazole N-9: 2- [2- {2- (2,2 -Dimethoxyphenoxyethoxy) ethyl} -bis (2-methoxyethyl)]-amine

W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-5: PF656 (manufactured by OMNOVA, fluorine-based)
W-6: PF6320 (manufactured by OMNOVA, fluorine-based)

SL-1: Cyclohexanone SL-2: Propylene glycol monomethyl ether acetate SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether SL-5: γ-butyrolactone SL-6: Propylene carbonate

  From Tables 4 to 5, it can be seen that the resist composition of the present invention has little resist pattern collapse and profile deterioration in immersion exposure, and elution into the immersion liquid is suppressed.

Claims (7)

(A) As a polymerization solvent, having a repeating unit represented by the following general formula (I) produced using a solvent selected from the group consisting of a chain ketone, a cyclic ketone, a chain ether and a cyclic ether A resist composition for immersion exposure, comprising: a resin that decomposes by the action of an acid and has increased solubility in an alkaline developer; and (B) a compound that generates an acid upon irradiation with an actinic ray or radiation. .

In general formula (I),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.   The resist composition for immersion exposure according to claim 1, wherein the polymerization solvent is a chain ketone or a cyclic ketone.   The resist composition for immersion exposure according to claim 1, wherein the polymerization solvent is a mixed solvent containing a cyclic ketone and a chain ketone.   The resist composition for immersion exposure according to claim 1, wherein the resin as the component (A) further has a repeating unit having a lactone group.   The resist composition for immersion exposure according to any one of claims 1 to 4, wherein the resin (A) further has a repeating unit having a hydroxyl group. A monomer containing a monomer represented by the following general formula (Im) is polymerized in a polymerization solvent containing a solvent selected from the group consisting of a chain ketone, a cyclic ketone, a chain ether and a cyclic ether. A method for producing a resin that decomposes by the action of an acid and increases the solubility in an alkaline developer.

In general formula (Im),
R ¹ represents a hydrogen atom, a halogen atom or an alkyl group.
R ² represents an alkyl group.
When there are a plurality of R ^{3 s} , each independently represents a halogen atom, an alkyl group, a cycloalkyl group, a cyano group or a hydroxyl group.
CA represents a cycloalkyl group having 5 or 6 carbon atoms.
A represents a single bond or a divalent linking group.
n represents 0 or a positive integer.   A pattern forming method comprising: forming a resist film using the resist composition according to claim 1; and subjecting the resist film to immersion exposure and development.