JP2008096743A - Positive resist composition for liquid immersion lithography and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition for liquid immersion lithography capable of suppressing substance elution in liquid immersion lithography and having excellent lithography characteristics, and a resist pattern forming method. <P>SOLUTION: The positive resist composition for liquid immersion lithography comprises a resin component (A) of which the alkali solubility increases under the action of an acid, an acid generator component (B) which generates an acid upon exposure to light and an acid propagator component (G). The resist pattern forming method includes the step of forming a resist film on a substrate using the positive resist composition for liquid immersion lithography; subjecting the resist film to liquid immersion lithography; and developing the resist film to form a resist pattern. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a positive resist composition for immersion exposure and a method for forming a resist pattern used for immersion exposure (immersion lithography).

  Lithography is often used to manufacture fine structures in various electronic devices such as semiconductor devices and liquid crystal devices. However, with the miniaturization of device structures, it is required to make finer resist patterns in the lithography process. At present, it is possible to form a fine resist pattern with a line width of about 90 nm in a state-of-the-art region using, for example, an ArF excimer laser by a lithography method. Required.

In order to achieve such a fine pattern formation, the development of an exposure apparatus and a corresponding resist is the first.
As the resist, a chemically amplified resist containing an acid generator that generates an acid upon irradiation with radiation and a base resin whose alkali solubility is changed by the action of the acid generated from the acid generator has attracted attention. Development is underway. According to the chemically amplified resist, not only high resolution is achieved, but also the catalytic reaction and chain reaction of the acid generated by radiation irradiation can be used, the quantum yield is 1 or more, and high sensitivity can be achieved. .
In a positive chemically amplified resist, a resin having an acid dissociable, dissolution inhibiting group is mainly used. As the acid dissociable, dissolution inhibiting group, for example, an acetal group such as an ethoxyethyl group, a tertiary alkyl group such as a tert-butyl group, a tert-butoxycarbonyl group, and a tert-butoxycarbonylmethyl group are known. Further, as a structural unit having an acid dissociable, dissolution inhibiting group in a resin component of a conventional ArF resist composition, as shown in Patent Document 1 below, a tertiary ester compound of (meth) acrylic acid, for example, 2-alkyl A structural unit derived from 2-adamantyl (meth) acrylate or the like is generally used. “(Meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

On the other hand, in an exposure apparatus, it is common to shorten the wavelength of the light source used, increase the numerical aperture (NA) of the lens (to increase the NA), or the like. For example, in general, the g-line with a main spectrum of a mercury lamp of 436 nm is used at a resist resolution of about 0.5 μm, and the i-line with a main spectrum of a mercury lamp of 365 nm is used at about 0.5 to 0.30 μm. 248 nm KrF excimer laser light is used at about 0.30 to 0.15 μm, and 193 nm ArF excimer laser light is used at about 0.15 μm or less. For further miniaturization, the use of F ₂ excimer laser (157 nm), Ar ₂ excimer laser (126 nm), EUV (extreme ultraviolet; 13.5 nm), EB (electron beam), X-ray, etc. has been studied. Yes.
However, shortening the wavelength of the light source requires an expensive new exposure apparatus. Further, when the NA is increased, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus is reduced even if the resolution is increased.

  Under such circumstances, a method called immersion exposure (immersion lithography) has been reported (for example, see Non-Patent Documents 1 to 3). This method uses a solvent (liquid) having a refractive index larger than the refractive index of air at the time of exposure between a lens and a resist film on the wafer, which is conventionally filled with an inert gas such as air or nitrogen. It is a method including a step of performing exposure (immersion exposure) in a state filled with an immersion medium.

According to such immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when a light source having a shorter wavelength or a high NA lens is used can be achieved, and the focus can be reduced. It is said that there is no decrease in depth. Moreover, immersion exposure can be performed using an existing exposure apparatus. Therefore, immersion exposure is expected to be able to form a resist pattern with low cost, high resolution, and excellent depth of focus, and in the manufacture of semiconductor devices that require a large capital investment. In particular, in terms of lithography characteristics such as resolution, the semiconductor industry is attracting a great deal of attention. Currently, water is mainly studied as an immersion medium.
JP-A-10-161313 Journal of Vacuum Science & Technology B (USA), 1999, Vol. 17, No. 6, pp. 3306-3309. Journal of Vacuum Science & Technology B (USA), 2001, Vol. 19, No. 6, pp. 2353-2356. Proceedings of SPIE (USA), 2002, 4691, pages 459-465.

However, there are still many unknown points in immersion exposure, and it is actually difficult to form a fine pattern at a level where it can actually be used. For example, in immersion exposure, as described above, the immersion medium comes into contact with the resist film and the lens during immersion exposure. For this reason, the resist film changes in quality due to elution of substances contained in the resist into the immersion medium, and the performance of the resist film deteriorates, or the refractive index of the immersion medium locally changes or dissolves due to the eluted substance. It is conceivable that the substance adversely affects the lithography characteristics due to contamination of the lens surface. That is, problems such as deterioration in sensitivity, a resulting resist pattern having a T-top shape, and surface roughness and swelling of the resist pattern are expected.
As a means for solving such a problem, for example, it is conceivable to reduce the affinity of the resist film for the immersion medium. For example, as an immersion medium, an aqueous solvent such as water is currently being studied. Therefore, reducing the hydrophilicity of the resist film surface, that is, increasing the hydrophobicity (water repellency) causes the above-mentioned problem. It is estimated that it is effective for improvement.

However, in order to increase the hydrophobicity of the resist film, it is necessary to change the composition of the resist, and the change in the resist composition is usually accompanied by deterioration of lithography characteristics. Therefore, even if the hydrophobicity of the resist film is increased for use in immersion exposure, it is difficult to form a fine pattern on the resist film at a practically usable level.
The present invention has been made in view of the above circumstances, and provides a positive resist composition for immersion exposure and a method for forming a resist pattern, which can suppress substance elution during immersion exposure and have excellent lithography properties. With the goal.

In order to achieve the above object, the present invention employs the following configuration.
That is, the first aspect of the present invention includes a resin component (A) whose alkali solubility is increased by the action of an acid, an acid generator component (B) that generates an acid upon exposure, and an acid multiplier component (G). A positive resist composition for immersion exposure.

  The second aspect of the present invention includes a step of forming a resist film on a substrate using the positive resist composition for immersion exposure according to the first aspect, a step of immersion exposure of the resist film, and the resist. A resist pattern forming method including a step of developing a film to form a resist pattern.

In the present specification and claims, “structural unit” means a monomer unit constituting a polymer (resin).
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
“Lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.
“Exposure” is a concept that encompasses not only light irradiation but also whole irradiation of radiation such as electron beam irradiation.

  ADVANTAGE OF THE INVENTION According to this invention, the elution of the substance at the time of immersion exposure can be suppressed, and the positive resist composition for immersion exposure which was excellent also in the lithography characteristic, and the resist pattern formation method can be provided.

≪Positive resist composition for immersion exposure≫
The positive resist composition for immersion exposure of the present invention comprises a resin component (A) whose alkali solubility is increased by the action of an acid (hereinafter referred to as component (A)), and an acid generator component which generates an acid upon exposure. (B) (hereinafter referred to as component (B)) and acid proliferator component (G) (hereinafter referred to as component (G)).
In such a positive resist composition for immersion exposure, the component (A) is insoluble in alkali before exposure, and when an acid is generated from the component (B) by exposure, the action of the acid causes the alkali of the component (A). Solubility increases. Therefore, in the formation of the resist pattern, when selective exposure is performed on the resist film obtained using the positive resist composition for immersion exposure, the exposed portion turns into alkali-soluble, while the unexposed portion becomes alkaline. Since it remains insoluble and does not change, a resist pattern can be formed by alkali development.
In the positive resist composition for immersion exposure according to the present invention, in addition to the components (A), (B) and (G), preferably a nitrogen-containing organic compound (D) (hereinafter, ( D) component)).
Hereinafter, each component will be described.

<(A) component>
In the present invention, the component (A) is not particularly limited, and those conventionally proposed as base resins for positive chemically amplified resists can be used, such as polyhydroxystyrene resins, acrylic resins, and the like. Examples include acid ester resins.
In the present invention, among them, the component (A) preferably has a structural unit derived from an acrylate ester.
A resin having such a structural unit is particularly highly transparent to an ArF excimer laser, and can be suitably used in lithography using an ArF excimer laser.
In the component (A), the proportion of the structural unit derived from the acrylate ester is preferably 20 mol% or more, and 50 mol% or more with respect to the total of all the structural units constituting the component (A). More preferably, 80 mol% or more is more preferable, and 100 mol% may be sufficient.

Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include a halogen atom, a lower alkyl group, and a halogenated lower alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
The α-position (α-position carbon atom) of a structural unit derived from an acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
In the acrylate ester, as the lower alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, Examples include lower linear or branched alkyl groups such as isopentyl group and neopentyl group.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group, and a hydrogen atom, a fluorine atom, a lower alkyl group or a fluorine atom. A lower alkyl group is more preferable, and a hydrogen atom or a methyl group is most preferable in terms of industrial availability.

The positive resist composition for immersion exposure of the present invention preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group as the component (A).
In addition to the structural unit (a1), the component (A) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
In addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a2), the component (A) is an acrylic containing a polar group-containing aliphatic hydrocarbon group. It is preferable to have a structural unit (a3) derived from an acid ester.

・ Structural unit (a1)
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A) insoluble in alkali before dissociation, and changes the entire component (A) to alkali soluble after dissociation. If it is a thing, the thing proposed until now as an acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resists can be used. Generally, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.

Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity.
“Aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-amyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Specific examples of the aliphatic cyclic group include, for example, a monocycloalkane, a bicycloalkane, a tricycloalkane, which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group, Examples thereof include a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as tetracycloalkane. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in a structural unit represented by the following general formula (a1 ″), an aliphatic cyclic group such as an adamantyl group, such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—); And a group having a branched alkylene group having a tertiary carbon atom bonded thereto.

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１５、Ｒ^１６はそれぞれ独立してアルキル基を示す。］

[Wherein, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

In the general formula (a1 ″), the halogen atom, lower alkyl group or halogenated lower alkyl group of R is a halogen atom, lower alkyl group or halogenated lower alkyl group which may be bonded to the α-position of the acrylate ester. It is the same.
R ¹⁵ and R ¹⁶ each independently represent an alkyl group, and the alkyl group may be linear or branched, and preferably has 1 to 5 carbon atoms.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級アルキル基または脂肪族環式基を表す。］

[Wherein, R ^{1 ′} and R ^{2 ′} each independently represent a hydrogen atom or a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

In the above formula, n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the lower alkyl group for R ^{1 ′} and R ^{2 ′} include the same lower alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, at least one of R ^{1 ′} and R ^{2 ′} is preferably a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

[Wherein, R ^{1 ′} , n and Y are the same as described above. ]

Examples of the lower alkyl group for Y include the same lower alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状または分岐鎖状のアルキル基または水素原子であり、Ｒ^１９は直鎖状、分岐鎖状または環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represent a linear or branched alkyl group or a hydrogen atom, and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include groups excluding hydrogen atoms. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of R ¹⁷ And may be combined.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２はアルキレン基または脂肪族環式基を示す。］

[Wherein, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents an alkylene group or an aliphatic cyclic group. ]

In the general formula (a1-0-1), the halogen atom, lower alkyl group or halogenated lower alkyl group of R is a halogen atom, lower alkyl group or halogenated lower group which may be bonded to the α-position of the acrylate ester. It is the same as the alkyl group.
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. A tertiary alkyl ester type acid dissociable, dissolution inhibiting group is preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Y ² is preferably an alkylene group having 1 to 4 carbon atoms or a divalent aliphatic cyclic group, except that a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. The same as described for the “aliphatic cyclic group” can be used.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［上記式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；ｍは０または１を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５の低級アルキル基を表す。］

[In the above formula, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; M represents 0 or 1; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

R ¹ ′ and R ² ′ are preferably at least one hydrogen atom, more preferably a hydrogen atom. n is preferably 0 or 1.

X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group exemplified in X ¹ above.
Examples of the aliphatic cyclic group for Y include the same groups as those exemplified above in the description of “aliphatic cyclic group”.

  Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by the general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) or (a1-1-35) to (a1- It is more preferable to use at least one selected from structural units represented by 1-41).
Furthermore, as the structural unit (a1), in particular, those represented by the following general formula (a1-1-01) including the structural units of the formulas (a1-1-1) to (a1-1-4) The following general formula (a1-1-02) including the structural units of formulas (a1-1-35) to (a1-1-41) is also preferable.

（式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１１は低級アルキル基を示す。）

(In the formula, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group.)

（式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜３の整数を表す。）

(In the formula, R represents a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² represents a lower alkyl group, and h represents an integer of 1 to 3.)

In general formula (a1-1-01), R is the same as defined above. The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably a methyl group.

In general formula (a1-1-02), R is the same as defined above. The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 or 2, and most preferably 2.

  In the component (A), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 50 mol%, based on all structural units constituting the component (A). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a2)
The component (A) preferably has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the lactone cyclic group of the structural unit (a2) is used for forming a resist film, the lactone cyclic group increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

  More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、ハロゲン原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ’は水素原子、低級アルキル基、または炭素数１〜５のアルコキシ基であり、ｍは０または１の整数であり、Ａは炭素数１〜５のアルキレン基または酸素原子である。］

[Wherein, R is a hydrogen atom, a halogen atom, a lower alkyl group or a halogenated lower alkyl group, R ′ is a hydrogen atom, a lower alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m is 0 or 1 is an integer, and A is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Specific examples of the alkylene group having 1 to 5 carbon atoms of A include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

  Among these, it is preferable to use at least one selected from general formulas (a2-1) to (a2-5), and at least one selected from general formulas (a2-1) to (a2-3). It is preferable to use more than one species. Specifically, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3) -2), at least one selected from (a2-3-9) and (a2-3-10) is preferably used.

In the component (A), as the structural unit (a2), one type of structural unit may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a2) in the component (A) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, based on the total of all structural units constituting the component (A). 50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a3)
The component (A) preferably has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. By having the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a polycyclic aliphatic hydrocarbon group (polycyclic group). . As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which one or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. Specific examples include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the following formula (a3-2), the following formula ( The structural unit represented by a3-3) is preferred.

（式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(Wherein R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3-position of the adamantyl group is particularly preferred.

  In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all the structural units constituting the component (A). More preferred is ˜25 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) is sufficiently obtained, and by setting the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a4)
The component (A) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3) described above. For ArF excimer laser, for KrF excimer laser (preferably ArF excimer laser) A number of conventionally known resins can be used for resist resins such as
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used for the resin component of the resist composition.
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

（式中、Ｒは前記と同じである。）

(In the formula, R is as defined above.)

  When the structural unit (a4) is contained in the component (A), the structural unit (a4) is contained in an amount of 1 to 30 mol%, preferably 10 to 10% of the total of all the structural units constituting the component (A). It is preferable to contain 20 mol%.

  In the present invention, the component (A) is preferably a resin (polymer) having the structural unit (a1), and in addition to the structural unit (a1), the structural unit (a2) and / or the structural unit (a3). It is more preferable that the resin (copolymer) has a). Examples of the resin include resins composed of the structural units (a1), (a2) and (a3), resins composed of the structural units (a1), (a2), (a3) and (a4). .

In the component (A), as the resin, one type may be used alone, or two or more types may be used in combination.
In the present invention, as the resin, those containing the following combination of structural units are particularly preferable.

［式中、Ｒは前記と同じであり、Ｒ^２０は低級アルキル基である。］

[Wherein, R is the same as defined above, and R ²⁰ represents a lower alkyl group. ]

In formula (A1-11), the lower alkyl group for R ^{20 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably a methyl group.

The component (A) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
In addition, the component (A) is used in combination with a chain transfer agent such as, for example, HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH at the time of the polymerization. A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a resin having a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective for.

The weight average molecular weight (Mw) of the component (A) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and most preferably 5000 to 20000. preferable. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  As the onium salt acid generator, for example, an acid generator represented by the following general formula (b-0) can be preferably used.

[Wherein, R ⁵¹ represents a linear, branched or cyclic alkyl group, or a linear, branched or cyclic fluorinated alkyl group; R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, linear or A branched alkyl group, a linear or branched halogenated alkyl group, or a linear or branched alkoxy group; R ⁵³ is an aryl group which may have a substituent; u '' Is an integer of 1 to 3. ]

In General Formula (b-0), R ⁵¹ represents a linear, branched, or cyclic alkyl group, or a linear, branched, or cyclic fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. The fluorination rate of the fluorinated alkyl group (ratio of the number of substituted fluorine atoms to the total number of hydrogen atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%, and particularly Those in which all hydrogen atoms are substituted with fluorine atoms are preferred because the strength of the acid is increased.
R ⁵¹ is most preferably a linear alkyl group or a fluorinated alkyl group.

R ⁵² represents a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group, a linear or branched alkyl halide group, or a linear or branched alkoxy group.
In R ⁵² , examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom, and a fluorine atom is preferable.
In R ⁵² , the alkyl group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
In R ⁵² , the halogenated alkyl group is a group in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms. Examples of the alkyl group herein are the same as the “alkyl group” in R ⁵² . Examples of the halogen atom to be substituted include the same as those described above for the “halogen atom”. In the halogenated alkyl group, it is desirable that 50 to 100% of the total number of hydrogen atoms are substituted with halogen atoms, and it is more preferable that all are substituted.
In R ⁵² , the alkoxy group is linear or branched, and the carbon number thereof is preferably 1 to 5, particularly 1 to 4, and more preferably 1 to 3.
Among these, R ⁵² is preferably a hydrogen atom.

R ⁵³ is an aryl group which may have a substituent, and examples of the structure of the basic ring (matrix ring) excluding the substituent include a naphthyl group, a phenyl group, an anthracenyl group, and the like. From the viewpoint of absorption of exposure light such as ArF excimer laser, a phenyl group is desirable.
Examples of the substituent include a hydroxyl group and a lower alkyl group (straight or branched chain, preferably having 5 or less carbon atoms, particularly preferably a methyl group).
As the aryl group for R ^53, an aryl group having no substituent is more preferable.
u ″ is an integer of 1 to 3, preferably 2 or 3, and particularly preferably 3.

  Preferable examples of the acid generator represented by the general formula (b-0) include the following.

  The acid generator represented by general formula (b-0) can be used alone or in combination of two or more.

  In addition, as another onium salt-based acid generator represented by the general formula (b-0), for example, a compound represented by the following general formula (b-1) or (b-2) is also preferable. Used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；Ｒ^４”は、直鎖、分岐または環状のアルキル基またはフッ素化アルキル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; R ⁴ ″ represents a linear, branched or cyclic alkyl group or fluorinated group. Represents an alkyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. At least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
The alkoxy group that may be substituted with a hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, a straight, include alkyl groups such as branched or cyclic. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group, respectively.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and 6 carbon atoms. Most preferably, it is -10.
The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. It is preferable because the strength of the acid is increased.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
As the alkyl group for R ⁵ ″ to R ⁶ ″, the same as the alkyl groups for R ¹ ″ to R ³ ″ can be used.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

  Specific examples of the onium salt acid generators represented by the formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or the same Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate. In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Preferably it is C3.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ³¹ , a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms which has no substituent.

As the organic group for R ³² , a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ’’は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3. ]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more, and still more preferably 90% or more.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracyl group, or a phenanthryl group. And heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen, sulfur, and nitrogen atoms. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group, and most preferably a partially fluorinated alkyl group.
The fluorinated alkyl group in R ³⁵ preferably has 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more fluorinated. This is preferable because the strength of the acid is increased. Most preferred is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 85 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

  Of the above exemplified compounds, the following four compounds are preferred.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

As the component (B), one type of these acid generators may be used alone, or two or more types may be used in combination.
In the present invention, it is particularly preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B).
The content of the component (B) in the positive resist composition for immersion exposure according to the present invention is 0.5 to 30 parts by mass, preferably 1 to 15 parts by mass with respect to 100 parts by mass of the component (A). . By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<(G) component>
The positive resist composition for immersion exposure of the present invention contains an acid multiplier component (G). By containing the said (G) component, the effect that the substance elution at the time of immersion exposure can be suppressed and it is excellent also in a lithography characteristic is acquired.
In the positive resist composition for immersion exposure according to the present invention, an acid is generated from the component (B) by exposure. The (G) component is decomposed by the acid to generate a free acid, and the (G) component is further decomposed by the free acid to generate a free acid. In this way, the (G) component is chain-decomposed by exposure to generate a large number of free acid molecules.

As the component (G), as described above, it can be decomposed by the action of an acid generated from the component (B) by exposure and newly generate an acid by itself to proliferate the acid in an autocatalytic manner. For example, a compound having a bridged carbocyclic skeleton structure is preferable.
Here, the “compound having a bridged carbocyclic skeleton structure” refers to a compound having a structure (hereinafter sometimes simply referred to as “bridged carbocycle”) formed by a bridge bond between a plurality of carbocycles in the molecule. Show.
The compound having the bridged carbocyclic skeleton structure has a bridging bond, whereby the molecule is stiffened and the thermal stability of the compound is improved.
The number of carbocycles is preferably 2-6, more preferably 2-3.
In the bridged carbocycle, part or all of the hydrogen atoms may be substituted with an alkyl group, an alkoxy group or the like. As the said alkyl group, C1-C6 is preferable, 1-3 are more preferable, and a methyl group, an ethyl group, a propyl group etc. are mentioned specifically ,. As the said alkoxy group, C1-C6 is preferable, 1-3 are more preferable, and a methoxy group, an ethoxy group, etc. are mentioned specifically ,. The bridged carbocycle may have an unsaturated bond such as a double bond.

  In the present invention, the bridged carbocycle has a hydroxyl group and a sulfonate group represented by the following general formula (Gs) on the carbon atom adjacent to the carbon atom to which the hydroxyl group is bonded. Particularly preferred.

［式中、Ｒ^０は脂肪族基、芳香族基又は複素環式基を示す。］

[Wherein, R ⁰ represents an aliphatic group, an aromatic group or a heterocyclic group. ]

In the formula (Gs), R ⁰ represents an aliphatic group, an aromatic group, or a heterocyclic group.
In R ⁰ , examples of the aliphatic group include a chain or cyclic alkyl group or alkenyl group, and the number of carbon atoms is preferably 1 to 12, and more preferably 1 to 8.
The aromatic group may be a monocyclic group or a polycyclic group, and specific examples thereof include an aryl group.
The heterocyclic group may be a monocyclic group or a polycyclic group, and examples thereof include those derived from various conventionally known heterocyclic compounds.
The aliphatic group, aromatic group and heterocyclic group may have a substituent, and examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an amino group, and a substituted amino group. It is done.
Specific examples of the aliphatic group and the aromatic group include, for example, methyl group, ethyl group, propyl group, butyl group, acyl group, hexyl group, vinyl group, propylene group, allyl group, cyclohexyl group, cyclooctyl group, A bicyclo hydrocarbon group, a tricyclo hydrocarbon group, a phenyl group, a tolyl group, a benzyl group, a phenethyl group, a naphthyl group, a naphthylmethyl group, or a substituted product thereof can be exemplified.
Examples of the heterocyclic group include various heterocyclic compounds, for example, five-membered ring compounds containing one hetero atom such as furan, thiophene, pyrrole, benzofuran, thionaphthene, indole, carbazole, or condensed ring compounds thereof; oxazole, thiazole 5-membered ring compounds containing two heteroatoms such as pyrazole, or condensed ring compounds thereof; 6-membered ring compounds containing one heteroatom such as pyran, pyron, coumarin, pyridine, quinoline, isoquinoline, acridine, etc. or condensed ring compounds thereof And various derivatives derived from six-membered ring compounds containing two heteroatoms such as pyridazine, pyrimidine, pyrazine, and phthalidine, or condensed ring compounds thereof.

In the present invention, when the component (G) has a hydroxyl group and a sulfonate group represented by the general formula (Gs) on the bridged carbocycle, the component (G) ) Decomposed by the action of an acid generated from the component to newly generate an acid (R ⁰ SO ₃ H). Thus, by exposure, one acid increases in one reaction, and as the reaction proceeds, the reaction accelerates and the component (G) decomposes in a chain.
In such a case, the strength of the acid generated is preferably 3 or less, particularly preferably 2 or less, as the acid dissociation constant (pKa). If pKa is 3 or less, the generated acid itself is more likely to induce autolysis. Conversely, if the acid is weaker than this, it is difficult to cause autolysis.
Examples of the acid (R ⁰ SO ₃ H) released by the above reaction include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic acid, Cyclohexanesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, 2,2,2-trifluoroethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, p-bromobenzenesulfonic acid, p-nitrobenzenesulfonic acid, 2- Examples thereof include thiophenesulfonic acid, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid and the like.

  More specifically, as the component (G), compounds represented by the following general formulas (G1) to (G4) (hereinafter, compounds corresponding to the respective general formulas are referred to as compounds (G1) to (G4). ).

［式中、Ｒ^１は水素原子、脂肪族基又は芳香族基を示し；Ｒ^２は脂肪族基、芳香族基又は複素環式基を示す。］

[Wherein, R ¹ represents a hydrogen atom, an aliphatic group or an aromatic group; R ² represents an aliphatic group, an aromatic group or a heterocyclic group. ]

In the general formulas (G1) to (G3), R ¹ represents a hydrogen atom, an aliphatic group, or an aromatic group.
In R ¹ , the aliphatic group and aromatic group are the same as the aliphatic group and aromatic group in R ⁰ . R ¹ is preferably an aliphatic group or an aromatic group, more preferably an aliphatic group, particularly preferably a lower alkyl group, and most preferably a methyl group.
In the general formulas (G1) to (G4), R ² represents an aliphatic group, an aromatic group, or a heterocyclic group, and examples thereof include the same as R ⁰ described above. R ² is preferably an aliphatic group or an aromatic group, more preferably an aromatic group, particularly preferably a phenyl group, and most preferably a phenyl group having a substituent (preferably one methyl group). preferable.

In the compounds (G1) to (G4), the compound (G1) has a crosslinking bond at the 1,3-position of the bicyclo compound, and the compound (G2) and the compound (G3) have a crosslinking bond at the 1,4-position of the bicyclo compound. And the compound (G4) has a crosslinking bond at positions 1 and 6 of the bicyclo compound (decalin).
Therefore, in the compounds (G1) to (G4), the conformational change of the cyclohexane ring is highly suppressed, and the ring structure exhibits rigidity.

  In the component (G), for example, the general formula (Gs) is bonded to a hydroxyl group and a carbon atom adjacent to the carbon atom to which the hydroxyl group is bonded on the bridged carbocycle such as the compounds (G1) to (G4). The compound having a sulfonate group represented by the above is easily synthesized by reacting a diol compound with a halide of sulfonic acid. This diol compound has two isomers, cis and trans. The cis isomer is more thermally stable and is preferably used. In addition, the compound can be stably stored as long as no acid is present.

  Preferred specific examples of the component (G) are listed below.

  As the component (G), among the above, the compound (G1) or the compound (G2) is preferable and the compound (G1) is more preferable because the effects of the present invention are good. Specifically, at least one selected from the chemical formulas (G1-1) to (G1-8) is preferably used, and the chemical formula (G1-5) is most preferable.

In this invention, (G) component may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the component (G) is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (A), and 0.5 to Most preferably, it is 5 parts by mass. When the content is at least the lower limit value, substance elution during immersion exposure is further suppressed. Further, the lithography characteristics are further improved. On the other hand, when the content is not more than the upper limit value, a balance with the component (B) can be achieved, and the pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

  In the positive resist composition for immersion exposure according to the present invention, the mixing ratio of the component (G) and the component (B) is preferably 9: 1 to 1: 9 in terms of molar ratio, More preferably, it is -5: 5, and it is especially preferable that it is 9: 1-7: 3. The effect of this invention improves more as the ratio of (G) component is more than the lower limit of the said range. On the other hand, when the proportion of the component (G) is not more than the upper limit of the above range, the balance with the component (B) is good, and the pattern is sufficiently formed.

<(D) component>
The positive resist composition for immersion exposure according to the present invention further includes a nitrogen-containing organic compound (D) (hereinafter referred to as the (D) component) as an optional component in order to improve the resist pattern shape, stability over time and the like. It is preferable to contain.
Since a wide variety of components (D) have already been proposed, any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity.
“Aliphatic cyclic group” means a monocyclic group or polycyclic group having no aromaticity.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine and tri-n-octylamine are particularly preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
(D) A component may be used independently and may be used in combination of 2 or more type.
In the present invention, it is particularly preferable to use a trialkylamine as the component (D).
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

<Optional component>
The positive resist composition for immersion exposure of the present invention includes an organic carboxylic acid and phosphorus oxo as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape and stability with time. At least one compound (E) selected from the group consisting of acids and derivatives thereof (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  The positive resist composition for immersion exposure according to the present invention may further contain a miscible additive as desired, for example, an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, A dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

The positive resist composition for immersion exposure of the present invention can be produced by dissolving a material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution, and any one of conventionally known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol A compound having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, or propylene glycol monoacetate, monomethyl ether, monoethyl ether of the polyhydric alcohol or the compound having an ester bond, A monoalkyl ether such as monopropyl ether or monobutyl ether or an ether bond such as monophenyl ether Derivatives of polyhydric alcohols such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred among these; cyclic ethers such as dioxane, methyl lactate, lactic acid Esters such as ethyl (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, di Aromatic organic solvents such as benzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, amylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is preferable. The mixing ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, but is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of component (S) used is not particularly limited, but it is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. -20% by mass, preferably 5-15% by mass.

The positive resist composition for immersion exposure according to the present invention has an effect that it can suppress substance elution during immersion exposure and is excellent in lithography characteristics.
Although the reason is not clear, the positive resist composition for immersion exposure of the present invention further contains an acid multiplier component (G) in addition to the resin component (A) and the acid generator component (B). Therefore, it is estimated that the effect of the present invention can be obtained. The component (G) is decomposed by the action of an acid generated from the component (B) upon exposure, and newly generates an acid itself to proliferate the acid in an autocatalytic manner. Thereby, it is possible to improve sensitivity, and it is considered that the lithography characteristics are improved. Moreover, the usage-amount of (B) component can be reduced by using the (G) component which generate | occur | produces an acid as mentioned above. Thereby, it is thought that the substance elution to the immersion solvent of the resist material at the time of immersion exposure can be suppressed more.

Furthermore, in the present invention, as described above, substance elution into the immersion solvent is suppressed. For this reason, it is possible to suppress the alteration of the resist film and the change in the refractive index of the immersion solvent. Therefore, by suppressing the change in the refractive index of the immersion solvent, the swell of the formed resist pattern and the line edge roughness (unevenness on the pattern side wall) are reduced, and the lithography properties such as the shape are improved. Further, the contamination of the lens of the exposure apparatus can be reduced, so that it is not necessary to take a protective measure against these, and the process and the exposure apparatus can be simplified.
In addition, according to the positive resist composition for immersion exposure of the present invention, a sensitization effect can be obtained. Also, according to the positive resist composition for immersion exposure of the present invention, a resist pattern with high resolution can be obtained. Can be formed.
Moreover, by using the positive resist composition for immersion exposure according to the present invention, it is possible to form a resist pattern having a good shape in which the generation of foreign matters and development defects is suppressed.

≪Resist pattern formation method≫
Next, a resist pattern forming method according to the second aspect of the present invention will be described.
The resist pattern forming method of the present invention includes a step of forming a resist film on a substrate using the positive resist composition for immersion exposure of the present invention, a step of immersing the resist film, and developing the resist film. And a step of forming a resist pattern.

A preferred example of the method for forming a resist pattern of the present invention is shown below.
First, a positive resist composition for immersion exposure according to the present invention is applied onto a substrate such as a silicon wafer using a spinner and the like, and then pre-baked (post-apply bake (PAB) treatment) to form a resist film. .
At this time, an organic or inorganic antireflection film may be provided between the substrate and the coating layer of the resist composition to form a two-layer laminate.
Further, an organic antireflection film can be further provided on the resist film to form a two-layer laminate, and further, a three-layer laminate in which an underlayer antireflection film is provided can be provided.
The antireflection film provided on the resist film is preferably soluble in an alkali developer.
The steps so far can be performed using a known method. The operating conditions and the like are preferably set as appropriate according to the composition and characteristics of the positive resist composition for immersion exposure to be used.

Next, liquid immersion lithography is selectively performed on the resist film obtained above through a desired mask pattern. At this time, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in this state.
The wavelength used for the exposure is not particularly limited, and can be performed using radiation such as an ArF excimer laser, a KrF excimer laser, or an F ₂ laser. The resist composition according to the present invention is effective for a KrF or ArF excimer laser, particularly an ArF excimer laser.

As described above, in the forming method of the present invention, during exposure, the immersion film is filled between the resist film and the lens at the lowest position of the exposure apparatus, and exposure (immersion exposure) is performed in that state.
The immersion medium used at this time is preferably a solvent having a refractive index larger than that of air and smaller than that of a resist film formed using a positive resist composition for immersion exposure. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.

Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).

  The positive resist composition for immersion exposure of the present invention is particularly resistant to adverse effects by water, and is excellent in sensitivity and resist pattern profile shape. Therefore, water is used as a solvent having a refractive index larger than that of air. Preferably used. Water is also preferable from the viewpoints of cost, safety, environmental problems, and versatility.

  Next, after the immersion exposure step is completed, post-exposure heating (post-exposure baking (PEB)) is performed, and subsequently, development processing is performed using an alkaline developer composed of an alkaline aqueous solution. And preferably, water rinsing is performed using pure water. In the water rinse, for example, water is dropped or sprayed on the surface of the substrate while rotating the substrate to wash away the developer on the substrate and the positive resist composition for immersion exposure dissolved by the developer. Then, drying is performed to obtain a resist pattern in which the resist film (the coating film of the positive resist composition for immersion exposure) is patterned into a shape corresponding to the mask pattern.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
<Resin component (A)>
In the following Examples 1 to 3 and Comparative Example 1, the resin (A) -1 used as the component (A) is copolymerized by a known dropping polymerization method using the following monomers (1) to (3). Obtained.

About the obtained resin (A) -1, GPC (gel permeation chromatography) measurement was performed, and when the mass average molecular weight (Mw) and dispersity (Mw / Mn) were calculated | required, Mw of resin (A) -1 was obtained. Was 10,000 and Mw / Mn was 2.0.
The structure of Resin (A) -1 is shown below.
In the formula, the number given to the lower right of () indicates the ratio (mol%; composition ratio) of each structural unit to the total of all the structural units constituting the resin.

(Examples 1 to 3, Comparative Example 1)
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition for immersion exposure.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(B) -1: Di (1-naphthyl) phenylsulfonium nonafluorobutanesulfonate.
(G) -1: a compound represented by the following chemical formula (G1-5).

(D) -1: tri-n-pentylamine.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

  The following evaluation was performed using the obtained positive resist composition for immersion exposure.

<Measurement of eluate>
Each of the positive resist compositions for immersion exposure in Examples 1 to 3 and Comparative Example 1 was applied on a silicon wafer having a diameter of 8 inches using a spinner, and pre-baked on a hot plate at 110 ° C. for 60 seconds. By drying, a resist film having a thickness of 150 nm was formed.
Next, on the resist film, one drop (50 μl) of pure water is dropped using VRC310S (manufactured by SSE Co., Ltd.), and the linear velocity is drawn so as to draw a circle from the center of the wafer at room temperature. Then, the droplet was moved (total contact area 221.56 cm ² of the resist film in contact with the droplet).
Thereafter, the droplets are collected and analyzed by an analyzer Agilent-HP1100 LC-MSD (manufactured by Agilent Technologies), and the cation part (PAG +) of the component (B) and the anion part (PAG−) of the component (B). ), And the elution amount (mol / cm ² ) of the anion part (GA−) and (D) component of the (G) component, respectively.

Moreover, using the positive resist compositions for immersion exposure in Examples 1 to 3 and Comparative Example 1, a resist film was formed in the same manner as described above, and an ArF exposure apparatus NSR-S302 was used for the resist film. Then, open frame exposure (exposure without a mask) was performed with an ArF excimer laser (193 nm).
Next, on the exposed resist film, the droplet is moved by the same operation as described above, and then analyzed in the same manner as described above, and the cation part (PAG +) of the component (B) and the anion of the component (B) The elution amount (mol / cm ² ) of the part (PAG-), the anion part (GA-) of the component (G) and the component (D) was determined. The above results are shown in Table 2.

  As is apparent from the results in Table 2, the positive resist compositions for immersion exposure of Examples 1 to 3 containing an acid proliferating agent into the immersion medium (water) before and after the exposure treatment. The total elution amount was less than 10% compared to the positive resist composition for immersion exposure of Comparative Example 1 containing no acid proliferating agent, and it was confirmed that the elution suppression effect was high. In particular, it was confirmed that the amount of elution of PAG- after exposure was smaller in Examples 1 to 3 than in Comparative Example 1.

In the measurement of the eluate, the elution amount before exposure is for evaluating the elution amount in the unexposed area when a resist pattern is formed by performing selective exposure, and the elution amount after exposure is determined by exposure. It is for evaluating the elution amount in the part.
Therefore, the positive resist compositions for immersion exposure according to Examples 1 to 3 according to the present invention are subjected to immersion exposure because there is little substance elution into the immersion medium (water) both before and after exposure. It was confirmed that the resist composition for immersion exposure used in the resist pattern forming method including the steps can be suitably used.

<Evaluation of lithography properties>
By applying an organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) onto an 8-inch silicon wafer using a spinner, baking on a hot plate at 205 ° C. for 60 seconds and drying. An organic antireflection film having a thickness of 77 nm was formed.
On the organic antireflection film, the positive resist compositions for immersion exposure of Examples 1 to 3 and Comparative Example 1 were respectively applied using a spinner, and prebaked (PAB) at 110 ° C. for 60 seconds on a hot plate. The resist film with a film thickness of 150 nm was formed by processing and drying.
Next, an ArF excimer laser (193 nm) was selectively irradiated through the mask pattern by an ArF exposure apparatus NSR-S302B (manufactured by Nikon; NA (numerical aperture) = 0.60, 2/3 annular illumination). .
Then, post-exposure heating (PEB) treatment was performed at 110 ° C. for 60 seconds, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 30 seconds, followed by pure water for 30 seconds. The sample was rinsed with water and shaken and dried.
As a result, in each of Examples 1 to 3 and Comparative Example 1, a line-and-space resist pattern (hereinafter referred to as an L / S pattern) having a line width of 120 nm and a pitch of 240 nm was formed.

(sensitivity)
The sensitivity (Eop, mJ / cm ² ) at which an L / S pattern having a line width of 120 nm and a pitch of 240 nm was formed was measured. The results are shown in Table 3.

(Resist pattern shape)
The L / S pattern thus obtained was observed with a scanning electron microscope (SEM). As a result, L obtained using the positive resist compositions for immersion exposure of Examples 1 to 3 and Comparative Example 1 were obtained. The / S pattern was confirmed to have a good shape.

  From the above results, it was confirmed that the positive resist compositions for immersion exposure of Examples 1 to 3 according to the present invention were as good as the comparative example 1 in the sensitization effect and the resist pattern shape. .

  Therefore, it was confirmed that the positive resist compositions for immersion exposure of Examples 1 to 3 according to the present invention can suppress substance elution during immersion exposure and have excellent lithography characteristics.

Claims (5)

  A positive for immersion exposure comprising a resin component (A) whose alkali solubility is increased by the action of an acid, an acid generator component (B) which generates an acid upon exposure, and an acid multiplier component (G) Type resist composition. The acid proliferator component (G) has the following general formula (G1)

[Wherein, R ¹ represents a hydrogen atom, an aliphatic group or an aromatic group; R ² represents an aliphatic group, an aromatic group or a heterocyclic group. A positive resist composition for immersion exposure according to claim 1, comprising a compound represented by the formula:   3. The positive resist composition for immersion exposure according to claim 1, wherein the amount of the acid multiplier component (G) used is 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin component (A). object.   The positive resist composition for immersion exposure according to any one of claims 1 to 3, further comprising a nitrogen-containing organic compound (D).   A step of forming a resist film on a substrate using the positive resist composition for immersion exposure according to any one of claims 1 to 4, a step of immersing the resist film, and developing the resist film A resist pattern forming method including a step of forming a resist pattern.